fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include <linux/raid/pq.h>
  29 #include <asm/div64.h>
  30 #include "compat.h"
  31 #include "ctree.h"
  32 #include "extent_map.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "print-tree.h"
  36 #include "volumes.h"
  37 #include "raid56.h"
  38 #include "async-thread.h"
  39 #include "check-integrity.h"
  40 #include "rcu-string.h"
  41 #include "math.h"
  42 #include "dev-replace.h"
  43
  44 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  45                                 struct btrfs_root *root,
  46                                 struct btrfs_device *device);
  47 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  48 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
  49 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
  50
  51 static DEFINE_MUTEX(uuid_mutex);
  52 static LIST_HEAD(fs_uuids);
  53
  54 static void lock_chunks(struct btrfs_root *root)
  55 {
  56         mutex_lock(&root->fs_info->chunk_mutex);
  57 }
  58
  59 static void unlock_chunks(struct btrfs_root *root)
  60 {
  61         mutex_unlock(&root->fs_info->chunk_mutex);
  62 }
  63
  64 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  65 {
  66         struct btrfs_device *device;
  67         WARN_ON(fs_devices->opened);
  68         while (!list_empty(&fs_devices->devices)) {
  69                 device = list_entry(fs_devices->devices.next,
  70                                     struct btrfs_device, dev_list);
  71                 list_del(&device->dev_list);
  72                 rcu_string_free(device->name);
  73                 kfree(device);
  74         }
  75         kfree(fs_devices);
  76 }
  77
  78 static void btrfs_kobject_uevent(struct block_device *bdev,
  79                                  enum kobject_action action)
  80 {
  81         int ret;
  82
  83         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
  84         if (ret)
  85                 pr_warn("Sending event '%d' to kobject: '%s' (%p): failed\n",
  86                         action,
  87                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
  88                         &disk_to_dev(bdev->bd_disk)->kobj);
  89 }
  90
  91 void btrfs_cleanup_fs_uuids(void)
  92 {
  93         struct btrfs_fs_devices *fs_devices;
  94
  95         while (!list_empty(&fs_uuids)) {
  96                 fs_devices = list_entry(fs_uuids.next,
  97                                         struct btrfs_fs_devices, list);
  98                 list_del(&fs_devices->list);
  99                 free_fs_devices(fs_devices);
 100         }
 101 }
 102
 103 static noinline struct btrfs_device *__find_device(struct list_head *head,
 104                                                    u64 devid, u8 *uuid)
 105 {
 106         struct btrfs_device *dev;
 107
 108         list_for_each_entry(dev, head, dev_list) {
 109                 if (dev->devid == devid &&
 110                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 111                         return dev;
 112                 }
 113         }
 114         return NULL;
 115 }
 116
 117 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 118 {
 119         struct btrfs_fs_devices *fs_devices;
 120
 121         list_for_each_entry(fs_devices, &fs_uuids, list) {
 122                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 123                         return fs_devices;
 124         }
 125         return NULL;
 126 }
 127
 128 static int
 129 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 130                       int flush, struct block_device **bdev,
 131                       struct buffer_head **bh)
 132 {
 133         int ret;
 134
 135         *bdev = blkdev_get_by_path(device_path, flags, holder);
 136
 137         if (IS_ERR(*bdev)) {
 138                 ret = PTR_ERR(*bdev);
 139                 printk(KERN_INFO "btrfs: open %s failed\n", device_path);
 140                 goto error;
 141         }
 142
 143         if (flush)
 144                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 145         ret = set_blocksize(*bdev, 4096);
 146         if (ret) {
 147                 blkdev_put(*bdev, flags);
 148                 goto error;
 149         }
 150         invalidate_bdev(*bdev);
 151         *bh = btrfs_read_dev_super(*bdev);
 152         if (!*bh) {
 153                 ret = -EINVAL;
 154                 blkdev_put(*bdev, flags);
 155                 goto error;
 156         }
 157
 158         return 0;
 159
 160 error:
 161         *bdev = NULL;
 162         *bh = NULL;
 163         return ret;
 164 }
 165
 166 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 167                         struct bio *head, struct bio *tail)
 168 {
 169
 170         struct bio *old_head;
 171
 172         old_head = pending_bios->head;
 173         pending_bios->head = head;
 174         if (pending_bios->tail)
 175                 tail->bi_next = old_head;
 176         else
 177                 pending_bios->tail = tail;
 178 }
 179
 180 /*
 181  * we try to collect pending bios for a device so we don't get a large
 182  * number of procs sending bios down to the same device.  This greatly
 183  * improves the schedulers ability to collect and merge the bios.
 184  *
 185  * But, it also turns into a long list of bios to process and that is sure
 186  * to eventually make the worker thread block.  The solution here is to
 187  * make some progress and then put this work struct back at the end of
 188  * the list if the block device is congested.  This way, multiple devices
 189  * can make progress from a single worker thread.
 190  */
 191 static noinline void run_scheduled_bios(struct btrfs_device *device)
 192 {
 193         struct bio *pending;
 194         struct backing_dev_info *bdi;
 195         struct btrfs_fs_info *fs_info;
 196         struct btrfs_pending_bios *pending_bios;
 197         struct bio *tail;
 198         struct bio *cur;
 199         int again = 0;
 200         unsigned long num_run;
 201         unsigned long batch_run = 0;
 202         unsigned long limit;
 203         unsigned long last_waited = 0;
 204         int force_reg = 0;
 205         int sync_pending = 0;
 206         struct blk_plug plug;
 207
 208         /*
 209          * this function runs all the bios we've collected for
 210          * a particular device.  We don't want to wander off to
 211          * another device without first sending all of these down.
 212          * So, setup a plug here and finish it off before we return
 213          */
 214         blk_start_plug(&plug);
 215
 216         bdi = blk_get_backing_dev_info(device->bdev);
 217         fs_info = device->dev_root->fs_info;
 218         limit = btrfs_async_submit_limit(fs_info);
 219         limit = limit * 2 / 3;
 220
 221 loop:
 222         spin_lock(&device->io_lock);
 223
 224 loop_lock:
 225         num_run = 0;
 226
 227         /* take all the bios off the list at once and process them
 228          * later on (without the lock held).  But, remember the
 229          * tail and other pointers so the bios can be properly reinserted
 230          * into the list if we hit congestion
 231          */
 232         if (!force_reg && device->pending_sync_bios.head) {
 233                 pending_bios = &device->pending_sync_bios;
 234                 force_reg = 1;
 235         } else {
 236                 pending_bios = &device->pending_bios;
 237                 force_reg = 0;
 238         }
 239
 240         pending = pending_bios->head;
 241         tail = pending_bios->tail;
 242         WARN_ON(pending && !tail);
 243
 244         /*
 245          * if pending was null this time around, no bios need processing
 246          * at all and we can stop.  Otherwise it'll loop back up again
 247          * and do an additional check so no bios are missed.
 248          *
 249          * device->running_pending is used to synchronize with the
 250          * schedule_bio code.
 251          */
 252         if (device->pending_sync_bios.head == NULL &&
 253             device->pending_bios.head == NULL) {
 254                 again = 0;
 255                 device->running_pending = 0;
 256         } else {
 257                 again = 1;
 258                 device->running_pending = 1;
 259         }
 260
 261         pending_bios->head = NULL;
 262         pending_bios->tail = NULL;
 263
 264         spin_unlock(&device->io_lock);
 265
 266         while (pending) {
 267
 268                 rmb();
 269                 /* we want to work on both lists, but do more bios on the
 270                  * sync list than the regular list
 271                  */
 272                 if ((num_run > 32 &&
 273                     pending_bios != &device->pending_sync_bios &&
 274                     device->pending_sync_bios.head) ||
 275                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 276                     device->pending_bios.head)) {
 277                         spin_lock(&device->io_lock);
 278                         requeue_list(pending_bios, pending, tail);
 279                         goto loop_lock;
 280                 }
 281
 282                 cur = pending;
 283                 pending = pending->bi_next;
 284                 cur->bi_next = NULL;
 285
 286                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 287                     waitqueue_active(&fs_info->async_submit_wait))
 288                         wake_up(&fs_info->async_submit_wait);
 289
 290                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 291
 292                 /*
 293                  * if we're doing the sync list, record that our
 294                  * plug has some sync requests on it
 295                  *
 296                  * If we're doing the regular list and there are
 297                  * sync requests sitting around, unplug before
 298                  * we add more
 299                  */
 300                 if (pending_bios == &device->pending_sync_bios) {
 301                         sync_pending = 1;
 302                 } else if (sync_pending) {
 303                         blk_finish_plug(&plug);
 304                         blk_start_plug(&plug);
 305                         sync_pending = 0;
 306                 }
 307
 308                 btrfsic_submit_bio(cur->bi_rw, cur);
 309                 num_run++;
 310                 batch_run++;
 311                 if (need_resched())
 312                         cond_resched();
 313
 314                 /*
 315                  * we made progress, there is more work to do and the bdi
 316                  * is now congested.  Back off and let other work structs
 317                  * run instead
 318                  */
 319                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 320                     fs_info->fs_devices->open_devices > 1) {
 321                         struct io_context *ioc;
 322
 323                         ioc = current->io_context;
 324
 325                         /*
 326                          * the main goal here is that we don't want to
 327                          * block if we're going to be able to submit
 328                          * more requests without blocking.
 329                          *
 330                          * This code does two great things, it pokes into
 331                          * the elevator code from a filesystem _and_
 332                          * it makes assumptions about how batching works.
 333                          */
 334                         if (ioc && ioc->nr_batch_requests > 0 &&
 335                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 336                             (last_waited == 0 ||
 337                              ioc->last_waited == last_waited)) {
 338                                 /*
 339                                  * we want to go through our batch of
 340                                  * requests and stop.  So, we copy out
 341                                  * the ioc->last_waited time and test
 342                                  * against it before looping
 343                                  */
 344                                 last_waited = ioc->last_waited;
 345                                 if (need_resched())
 346                                         cond_resched();
 347                                 continue;
 348                         }
 349                         spin_lock(&device->io_lock);
 350                         requeue_list(pending_bios, pending, tail);
 351                         device->running_pending = 1;
 352
 353                         spin_unlock(&device->io_lock);
 354                         btrfs_requeue_work(&device->work);
 355                         goto done;
 356                 }
 357                 /* unplug every 64 requests just for good measure */
 358                 if (batch_run % 64 == 0) {
 359                         blk_finish_plug(&plug);
 360                         blk_start_plug(&plug);
 361                         sync_pending = 0;
 362                 }
 363         }
 364
 365         cond_resched();
 366         if (again)
 367                 goto loop;
 368
 369         spin_lock(&device->io_lock);
 370         if (device->pending_bios.head || device->pending_sync_bios.head)
 371                 goto loop_lock;
 372         spin_unlock(&device->io_lock);
 373
 374 done:
 375         blk_finish_plug(&plug);
 376 }
 377
 378 static void pending_bios_fn(struct btrfs_work *work)
 379 {
 380         struct btrfs_device *device;
 381
 382         device = container_of(work, struct btrfs_device, work);
 383         run_scheduled_bios(device);
 384 }
 385
 386 static noinline int device_list_add(const char *path,
 387                            struct btrfs_super_block *disk_super,
 388                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 389 {
 390         struct btrfs_device *device;
 391         struct btrfs_fs_devices *fs_devices;
 392         struct rcu_string *name;
 393         u64 found_transid = btrfs_super_generation(disk_super);
 394
 395         fs_devices = find_fsid(disk_super->fsid);
 396         if (!fs_devices) {
 397                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 398                 if (!fs_devices)
 399                         return -ENOMEM;
 400                 INIT_LIST_HEAD(&fs_devices->devices);
 401                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 402                 list_add(&fs_devices->list, &fs_uuids);
 403                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 404                 fs_devices->latest_devid = devid;
 405                 fs_devices->latest_trans = found_transid;
 406                 mutex_init(&fs_devices->device_list_mutex);
 407                 device = NULL;
 408         } else {
 409                 device = __find_device(&fs_devices->devices, devid,
 410                                        disk_super->dev_item.uuid);
 411         }
 412         if (!device) {
 413                 if (fs_devices->opened)
 414                         return -EBUSY;
 415
 416                 device = kzalloc(sizeof(*device), GFP_NOFS);
 417                 if (!device) {
 418                         /* we can safely leave the fs_devices entry around */
 419                         return -ENOMEM;
 420                 }
 421                 device->devid = devid;
 422                 device->dev_stats_valid = 0;
 423                 device->work.func = pending_bios_fn;
 424                 memcpy(device->uuid, disk_super->dev_item.uuid,
 425                        BTRFS_UUID_SIZE);
 426                 spin_lock_init(&device->io_lock);
 427
 428                 name = rcu_string_strdup(path, GFP_NOFS);
 429                 if (!name) {
 430                         kfree(device);
 431                         return -ENOMEM;
 432                 }
 433                 rcu_assign_pointer(device->name, name);
 434                 INIT_LIST_HEAD(&device->dev_alloc_list);
 435
 436                 /* init readahead state */
 437                 spin_lock_init(&device->reada_lock);
 438                 device->reada_curr_zone = NULL;
 439                 atomic_set(&device->reada_in_flight, 0);
 440                 device->reada_next = 0;
 441                 INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 442                 INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
 443
 444                 mutex_lock(&fs_devices->device_list_mutex);
 445                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 446                 mutex_unlock(&fs_devices->device_list_mutex);
 447
 448                 device->fs_devices = fs_devices;
 449                 fs_devices->num_devices++;
 450         } else if (!device->name || strcmp(device->name->str, path)) {
 451                 name = rcu_string_strdup(path, GFP_NOFS);
 452                 if (!name)
 453                         return -ENOMEM;
 454                 rcu_string_free(device->name);
 455                 rcu_assign_pointer(device->name, name);
 456                 if (device->missing) {
 457                         fs_devices->missing_devices--;
 458                         device->missing = 0;
 459                 }
 460         }
 461
 462         if (found_transid > fs_devices->latest_trans) {
 463                 fs_devices->latest_devid = devid;
 464                 fs_devices->latest_trans = found_transid;
 465         }
 466         *fs_devices_ret = fs_devices;
 467         return 0;
 468 }
 469
 470 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 471 {
 472         struct btrfs_fs_devices *fs_devices;
 473         struct btrfs_device *device;
 474         struct btrfs_device *orig_dev;
 475
 476         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 477         if (!fs_devices)
 478                 return ERR_PTR(-ENOMEM);
 479
 480         INIT_LIST_HEAD(&fs_devices->devices);
 481         INIT_LIST_HEAD(&fs_devices->alloc_list);
 482         INIT_LIST_HEAD(&fs_devices->list);
 483         mutex_init(&fs_devices->device_list_mutex);
 484         fs_devices->latest_devid = orig->latest_devid;
 485         fs_devices->latest_trans = orig->latest_trans;
 486         fs_devices->total_devices = orig->total_devices;
 487         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 488
 489         /* We have held the volume lock, it is safe to get the devices. */
 490         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 491                 struct rcu_string *name;
 492
 493                 device = kzalloc(sizeof(*device), GFP_NOFS);
 494                 if (!device)
 495                         goto error;
 496
 497                 /*
 498                  * This is ok to do without rcu read locked because we hold the
 499                  * uuid mutex so nothing we touch in here is going to disappear.
 500                  */
 501                 name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 502                 if (!name) {
 503                         kfree(device);
 504                         goto error;
 505                 }
 506                 rcu_assign_pointer(device->name, name);
 507
 508                 device->devid = orig_dev->devid;
 509                 device->work.func = pending_bios_fn;
 510                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 511                 spin_lock_init(&device->io_lock);
 512                 INIT_LIST_HEAD(&device->dev_list);
 513                 INIT_LIST_HEAD(&device->dev_alloc_list);
 514
 515                 list_add(&device->dev_list, &fs_devices->devices);
 516                 device->fs_devices = fs_devices;
 517                 fs_devices->num_devices++;
 518         }
 519         return fs_devices;
 520 error:
 521         free_fs_devices(fs_devices);
 522         return ERR_PTR(-ENOMEM);
 523 }
 524
 525 void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
 526                                struct btrfs_fs_devices *fs_devices, int step)
 527 {
 528         struct btrfs_device *device, *next;
 529
 530         struct block_device *latest_bdev = NULL;
 531         u64 latest_devid = 0;
 532         u64 latest_transid = 0;
 533
 534         mutex_lock(&uuid_mutex);
 535 again:
 536         /* This is the initialized path, it is safe to release the devices. */
 537         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 538                 if (device->in_fs_metadata) {
 539                         if (!device->is_tgtdev_for_dev_replace &&
 540                             (!latest_transid ||
 541                              device->generation > latest_transid)) {
 542                                 latest_devid = device->devid;
 543                                 latest_transid = device->generation;
 544                                 latest_bdev = device->bdev;
 545                         }
 546                         continue;
 547                 }
 548
 549                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 550                         /*
 551                          * In the first step, keep the device which has
 552                          * the correct fsid and the devid that is used
 553                          * for the dev_replace procedure.
 554                          * In the second step, the dev_replace state is
 555                          * read from the device tree and it is known
 556                          * whether the procedure is really active or
 557                          * not, which means whether this device is
 558                          * used or whether it should be removed.
 559                          */
 560                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 561                                 continue;
 562                         }
 563                 }
 564                 if (device->bdev) {
 565                         blkdev_put(device->bdev, device->mode);
 566                         device->bdev = NULL;
 567                         fs_devices->open_devices--;
 568                 }
 569                 if (device->writeable) {
 570                         list_del_init(&device->dev_alloc_list);
 571                         device->writeable = 0;
 572                         if (!device->is_tgtdev_for_dev_replace)
 573                                 fs_devices->rw_devices--;
 574                 }
 575                 list_del_init(&device->dev_list);
 576                 fs_devices->num_devices--;
 577                 rcu_string_free(device->name);
 578                 kfree(device);
 579         }
 580
 581         if (fs_devices->seed) {
 582                 fs_devices = fs_devices->seed;
 583                 goto again;
 584         }
 585
 586         fs_devices->latest_bdev = latest_bdev;
 587         fs_devices->latest_devid = latest_devid;
 588         fs_devices->latest_trans = latest_transid;
 589
 590         mutex_unlock(&uuid_mutex);
 591 }
 592
 593 static void __free_device(struct work_struct *work)
 594 {
 595         struct btrfs_device *device;
 596
 597         device = container_of(work, struct btrfs_device, rcu_work);
 598
 599         if (device->bdev)
 600                 blkdev_put(device->bdev, device->mode);
 601
 602         rcu_string_free(device->name);
 603         kfree(device);
 604 }
 605
 606 static void free_device(struct rcu_head *head)
 607 {
 608         struct btrfs_device *device;
 609
 610         device = container_of(head, struct btrfs_device, rcu);
 611
 612         INIT_WORK(&device->rcu_work, __free_device);
 613         schedule_work(&device->rcu_work);
 614 }
 615
 616 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 617 {
 618         struct btrfs_device *device;
 619
 620         if (--fs_devices->opened > 0)
 621                 return 0;
 622
 623         mutex_lock(&fs_devices->device_list_mutex);
 624         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 625                 struct btrfs_device *new_device;
 626                 struct rcu_string *name;
 627
 628                 if (device->bdev)
 629                         fs_devices->open_devices--;
 630
 631                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 632                         list_del_init(&device->dev_alloc_list);
 633                         fs_devices->rw_devices--;
 634                 }
 635
 636                 if (device->can_discard)
 637                         fs_devices->num_can_discard--;
 638
 639                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 640                 BUG_ON(!new_device); /* -ENOMEM */
 641                 memcpy(new_device, device, sizeof(*new_device));
 642
 643                 /* Safe because we are under uuid_mutex */
 644                 if (device->name) {
 645                         name = rcu_string_strdup(device->name->str, GFP_NOFS);
 646                         BUG_ON(device->name && !name); /* -ENOMEM */
 647                         rcu_assign_pointer(new_device->name, name);
 648                 }
 649                 new_device->bdev = NULL;
 650                 new_device->writeable = 0;
 651                 new_device->in_fs_metadata = 0;
 652                 new_device->can_discard = 0;
 653                 spin_lock_init(&new_device->io_lock);
 654                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
 655
 656                 call_rcu(&device->rcu, free_device);
 657         }
 658         mutex_unlock(&fs_devices->device_list_mutex);
 659
 660         WARN_ON(fs_devices->open_devices);
 661         WARN_ON(fs_devices->rw_devices);
 662         fs_devices->opened = 0;
 663         fs_devices->seeding = 0;
 664
 665         return 0;
 666 }
 667
 668 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 669 {
 670         struct btrfs_fs_devices *seed_devices = NULL;
 671         int ret;
 672
 673         mutex_lock(&uuid_mutex);
 674         ret = __btrfs_close_devices(fs_devices);
 675         if (!fs_devices->opened) {
 676                 seed_devices = fs_devices->seed;
 677                 fs_devices->seed = NULL;
 678         }
 679         mutex_unlock(&uuid_mutex);
 680
 681         while (seed_devices) {
 682                 fs_devices = seed_devices;
 683                 seed_devices = fs_devices->seed;
 684                 __btrfs_close_devices(fs_devices);
 685                 free_fs_devices(fs_devices);
 686         }
 687         return ret;
 688 }
 689
 690 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 691                                 fmode_t flags, void *holder)
 692 {
 693         struct request_queue *q;
 694         struct block_device *bdev;
 695         struct list_head *head = &fs_devices->devices;
 696         struct btrfs_device *device;
 697         struct block_device *latest_bdev = NULL;
 698         struct buffer_head *bh;
 699         struct btrfs_super_block *disk_super;
 700         u64 latest_devid = 0;
 701         u64 latest_transid = 0;
 702         u64 devid;
 703         int seeding = 1;
 704         int ret = 0;
 705
 706         flags |= FMODE_EXCL;
 707
 708         list_for_each_entry(device, head, dev_list) {
 709                 if (device->bdev)
 710                         continue;
 711                 if (!device->name)
 712                         continue;
 713
 714                 ret = btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 715                                             &bdev, &bh);
 716                 if (ret)
 717                         continue;
 718
 719                 disk_super = (struct btrfs_super_block *)bh->b_data;
 720                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 721                 if (devid != device->devid)
 722                         goto error_brelse;
 723
 724                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 725                            BTRFS_UUID_SIZE))
 726                         goto error_brelse;
 727
 728                 device->generation = btrfs_super_generation(disk_super);
 729                 if (!latest_transid || device->generation > latest_transid) {
 730                         latest_devid = devid;
 731                         latest_transid = device->generation;
 732                         latest_bdev = bdev;
 733                 }
 734
 735                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 736                         device->writeable = 0;
 737                 } else {
 738                         device->writeable = !bdev_read_only(bdev);
 739                         seeding = 0;
 740                 }
 741
 742                 q = bdev_get_queue(bdev);
 743                 if (blk_queue_discard(q)) {
 744                         device->can_discard = 1;
 745                         fs_devices->num_can_discard++;
 746                 }
 747
 748                 device->bdev = bdev;
 749                 device->in_fs_metadata = 0;
 750                 device->mode = flags;
 751
 752                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 753                         fs_devices->rotating = 1;
 754
 755                 fs_devices->open_devices++;
 756                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 757                         fs_devices->rw_devices++;
 758                         list_add(&device->dev_alloc_list,
 759                                  &fs_devices->alloc_list);
 760                 }
 761                 brelse(bh);
 762                 continue;
 763
 764 error_brelse:
 765                 brelse(bh);
 766                 blkdev_put(bdev, flags);
 767                 continue;
 768         }
 769         if (fs_devices->open_devices == 0) {
 770                 ret = -EINVAL;
 771                 goto out;
 772         }
 773         fs_devices->seeding = seeding;
 774         fs_devices->opened = 1;
 775         fs_devices->latest_bdev = latest_bdev;
 776         fs_devices->latest_devid = latest_devid;
 777         fs_devices->latest_trans = latest_transid;
 778         fs_devices->total_rw_bytes = 0;
 779 out:
 780         return ret;
 781 }
 782
 783 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 784                        fmode_t flags, void *holder)
 785 {
 786         int ret;
 787
 788         mutex_lock(&uuid_mutex);
 789         if (fs_devices->opened) {
 790                 fs_devices->opened++;
 791                 ret = 0;
 792         } else {
 793                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 794         }
 795         mutex_unlock(&uuid_mutex);
 796         return ret;
 797 }
 798
 799 /*
 800  * Look for a btrfs signature on a device. This may be called out of the mount path
 801  * and we are not allowed to call set_blocksize during the scan. The superblock
 802  * is read via pagecache
 803  */
 804 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 805                           struct btrfs_fs_devices **fs_devices_ret)
 806 {
 807         struct btrfs_super_block *disk_super;
 808         struct block_device *bdev;
 809         struct page *page;
 810         void *p;
 811         int ret = -EINVAL;
 812         u64 devid;
 813         u64 transid;
 814         u64 total_devices;
 815         u64 bytenr;
 816         pgoff_t index;
 817
 818         /*
 819          * we would like to check all the supers, but that would make
 820          * a btrfs mount succeed after a mkfs from a different FS.
 821          * So, we need to add a special mount option to scan for
 822          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
 823          */
 824         bytenr = btrfs_sb_offset(0);
 825         flags |= FMODE_EXCL;
 826         mutex_lock(&uuid_mutex);
 827
 828         bdev = blkdev_get_by_path(path, flags, holder);
 829
 830         if (IS_ERR(bdev)) {
 831                 ret = PTR_ERR(bdev);
 832                 goto error;
 833         }
 834
 835         /* make sure our super fits in the device */
 836         if (bytenr + PAGE_CACHE_SIZE >= i_size_read(bdev->bd_inode))
 837                 goto error_bdev_put;
 838
 839         /* make sure our super fits in the page */
 840         if (sizeof(*disk_super) > PAGE_CACHE_SIZE)
 841                 goto error_bdev_put;
 842
 843         /* make sure our super doesn't straddle pages on disk */
 844         index = bytenr >> PAGE_CACHE_SHIFT;
 845         if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_CACHE_SHIFT != index)
 846                 goto error_bdev_put;
 847
 848         /* pull in the page with our super */
 849         page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
 850                                    index, GFP_NOFS);
 851
 852         if (IS_ERR_OR_NULL(page))
 853                 goto error_bdev_put;
 854
 855         p = kmap(page);
 856
 857         /* align our pointer to the offset of the super block */
 858         disk_super = p + (bytenr & ~PAGE_CACHE_MASK);
 859
 860         if (btrfs_super_bytenr(disk_super) != bytenr ||
 861             disk_super->magic != cpu_to_le64(BTRFS_MAGIC))
 862                 goto error_unmap;
 863
 864         devid = btrfs_stack_device_id(&disk_super->dev_item);
 865         transid = btrfs_super_generation(disk_super);
 866         total_devices = btrfs_super_num_devices(disk_super);
 867
 868         if (disk_super->label[0]) {
 869                 if (disk_super->label[BTRFS_LABEL_SIZE - 1])
 870                         disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
 871                 printk(KERN_INFO "device label %s ", disk_super->label);
 872         } else {
 873                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
 874         }
 875
 876         printk(KERN_CONT "devid %llu transid %llu %s\n",
 877                (unsigned long long)devid, (unsigned long long)transid, path);
 878
 879         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 880         if (!ret && fs_devices_ret)
 881                 (*fs_devices_ret)->total_devices = total_devices;
 882
 883 error_unmap:
 884         kunmap(page);
 885         page_cache_release(page);
 886
 887 error_bdev_put:
 888         blkdev_put(bdev, flags);
 889 error:
 890         mutex_unlock(&uuid_mutex);
 891         return ret;
 892 }
 893
 894 /* helper to account the used device space in the range */
 895 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 896                                    u64 end, u64 *length)
 897 {
 898         struct btrfs_key key;
 899         struct btrfs_root *root = device->dev_root;
 900         struct btrfs_dev_extent *dev_extent;
 901         struct btrfs_path *path;
 902         u64 extent_end;
 903         int ret;
 904         int slot;
 905         struct extent_buffer *l;
 906
 907         *length = 0;
 908
 909         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
 910                 return 0;
 911
 912         path = btrfs_alloc_path();
 913         if (!path)
 914                 return -ENOMEM;
 915         path->reada = 2;
 916
 917         key.objectid = device->devid;
 918         key.offset = start;
 919         key.type = BTRFS_DEV_EXTENT_KEY;
 920
 921         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 922         if (ret < 0)
 923                 goto out;
 924         if (ret > 0) {
 925                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 926                 if (ret < 0)
 927                         goto out;
 928         }
 929
 930         while (1) {
 931                 l = path->nodes[0];
 932                 slot = path->slots[0];
 933                 if (slot >= btrfs_header_nritems(l)) {
 934                         ret = btrfs_next_leaf(root, path);
 935                         if (ret == 0)
 936                                 continue;
 937                         if (ret < 0)
 938                                 goto out;
 939
 940                         break;
 941                 }
 942                 btrfs_item_key_to_cpu(l, &key, slot);
 943
 944                 if (key.objectid < device->devid)
 945                         goto next;
 946
 947                 if (key.objectid > device->devid)
 948                         break;
 949
 950                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 951                         goto next;
 952
 953                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 954                 extent_end = key.offset + btrfs_dev_extent_length(l,
 955                                                                   dev_extent);
 956                 if (key.offset <= start && extent_end > end) {
 957                         *length = end - start + 1;
 958                         break;
 959                 } else if (key.offset <= start && extent_end > start)
 960                         *length += extent_end - start;
 961                 else if (key.offset > start && extent_end <= end)
 962                         *length += extent_end - key.offset;
 963                 else if (key.offset > start && key.offset <= end) {
 964                         *length += end - key.offset + 1;
 965                         break;
 966                 } else if (key.offset > end)
 967                         break;
 968
 969 next:
 970                 path->slots[0]++;
 971         }
 972         ret = 0;
 973 out:
 974         btrfs_free_path(path);
 975         return ret;
 976 }
 977
 978 /*
 979  * find_free_dev_extent - find free space in the specified device
 980  * @device:     the device which we search the free space in
 981  * @num_bytes:  the size of the free space that we need
 982  * @start:      store the start of the free space.
 983  * @len:        the size of the free space. that we find, or the size of the max
 984  *              free space if we don't find suitable free space
 985  *
 986  * this uses a pretty simple search, the expectation is that it is
 987  * called very infrequently and that a given device has a small number
 988  * of extents
 989  *
 990  * @start is used to store the start of the free space if we find. But if we
 991  * don't find suitable free space, it will be used to store the start position
 992  * of the max free space.
 993  *
 994  * @len is used to store the size of the free space that we find.
 995  * But if we don't find suitable free space, it is used to store the size of
 996  * the max free space.
 997  */
 998 int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 999                          u64 *start, u64 *len)
1000 {
1001         struct btrfs_key key;
1002         struct btrfs_root *root = device->dev_root;
1003         struct btrfs_dev_extent *dev_extent;
1004         struct btrfs_path *path;
1005         u64 hole_size;
1006         u64 max_hole_start;
1007         u64 max_hole_size;
1008         u64 extent_end;
1009         u64 search_start;
1010         u64 search_end = device->total_bytes;
1011         int ret;
1012         int slot;
1013         struct extent_buffer *l;
1014
1015         /* FIXME use last free of some kind */
1016
1017         /* we don't want to overwrite the superblock on the drive,
1018          * so we make sure to start at an offset of at least 1MB
1019          */
1020         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
1021
1022         max_hole_start = search_start;
1023         max_hole_size = 0;
1024         hole_size = 0;
1025
1026         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
1027                 ret = -ENOSPC;
1028                 goto error;
1029         }
1030
1031         path = btrfs_alloc_path();
1032         if (!path) {
1033                 ret = -ENOMEM;
1034                 goto error;
1035         }
1036         path->reada = 2;
1037
1038         key.objectid = device->devid;
1039         key.offset = search_start;
1040         key.type = BTRFS_DEV_EXTENT_KEY;
1041
1042         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1043         if (ret < 0)
1044                 goto out;
1045         if (ret > 0) {
1046                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1047                 if (ret < 0)
1048                         goto out;
1049         }
1050
1051         while (1) {
1052                 l = path->nodes[0];
1053                 slot = path->slots[0];
1054                 if (slot >= btrfs_header_nritems(l)) {
1055                         ret = btrfs_next_leaf(root, path);
1056                         if (ret == 0)
1057                                 continue;
1058                         if (ret < 0)
1059                                 goto out;
1060
1061                         break;
1062                 }
1063                 btrfs_item_key_to_cpu(l, &key, slot);
1064
1065                 if (key.objectid < device->devid)
1066                         goto next;
1067
1068                 if (key.objectid > device->devid)
1069                         break;
1070
1071                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
1072                         goto next;
1073
1074                 if (key.offset > search_start) {
1075                         hole_size = key.offset - search_start;
1076
1077                         if (hole_size > max_hole_size) {
1078                                 max_hole_start = search_start;
1079                                 max_hole_size = hole_size;
1080                         }
1081
1082                         /*
1083                          * If this free space is greater than which we need,
1084                          * it must be the max free space that we have found
1085                          * until now, so max_hole_start must point to the start
1086                          * of this free space and the length of this free space
1087                          * is stored in max_hole_size. Thus, we return
1088                          * max_hole_start and max_hole_size and go back to the
1089                          * caller.
1090                          */
1091                         if (hole_size >= num_bytes) {
1092                                 ret = 0;
1093                                 goto out;
1094                         }
1095                 }
1096
1097                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1098                 extent_end = key.offset + btrfs_dev_extent_length(l,
1099                                                                   dev_extent);
1100                 if (extent_end > search_start)
1101                         search_start = extent_end;
1102 next:
1103                 path->slots[0]++;
1104                 cond_resched();
1105         }
1106
1107         /*
1108          * At this point, search_start should be the end of
1109          * allocated dev extents, and when shrinking the device,
1110          * search_end may be smaller than search_start.
1111          */
1112         if (search_end > search_start)
1113                 hole_size = search_end - search_start;
1114
1115         if (hole_size > max_hole_size) {
1116                 max_hole_start = search_start;
1117                 max_hole_size = hole_size;
1118         }
1119
1120         /* See above. */
1121         if (hole_size < num_bytes)
1122                 ret = -ENOSPC;
1123         else
1124                 ret = 0;
1125
1126 out:
1127         btrfs_free_path(path);
1128 error:
1129         *start = max_hole_start;
1130         if (len)
1131                 *len = max_hole_size;
1132         return ret;
1133 }
1134
1135 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1136                           struct btrfs_device *device,
1137                           u64 start)
1138 {
1139         int ret;
1140         struct btrfs_path *path;
1141         struct btrfs_root *root = device->dev_root;
1142         struct btrfs_key key;
1143         struct btrfs_key found_key;
1144         struct extent_buffer *leaf = NULL;
1145         struct btrfs_dev_extent *extent = NULL;
1146
1147         path = btrfs_alloc_path();
1148         if (!path)
1149                 return -ENOMEM;
1150
1151         key.objectid = device->devid;
1152         key.offset = start;
1153         key.type = BTRFS_DEV_EXTENT_KEY;
1154 again:
1155         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1156         if (ret > 0) {
1157                 ret = btrfs_previous_item(root, path, key.objectid,
1158                                           BTRFS_DEV_EXTENT_KEY);
1159                 if (ret)
1160                         goto out;
1161                 leaf = path->nodes[0];
1162                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1163                 extent = btrfs_item_ptr(leaf, path->slots[0],
1164                                         struct btrfs_dev_extent);
1165                 BUG_ON(found_key.offset > start || found_key.offset +
1166                        btrfs_dev_extent_length(leaf, extent) < start);
1167                 key = found_key;
1168                 btrfs_release_path(path);
1169                 goto again;
1170         } else if (ret == 0) {
1171                 leaf = path->nodes[0];
1172                 extent = btrfs_item_ptr(leaf, path->slots[0],
1173                                         struct btrfs_dev_extent);
1174         } else {
1175                 btrfs_error(root->fs_info, ret, "Slot search failed");
1176                 goto out;
1177         }
1178
1179         if (device->bytes_used > 0) {
1180                 u64 len = btrfs_dev_extent_length(leaf, extent);
1181                 device->bytes_used -= len;
1182                 spin_lock(&root->fs_info->free_chunk_lock);
1183                 root->fs_info->free_chunk_space += len;
1184                 spin_unlock(&root->fs_info->free_chunk_lock);
1185         }
1186         ret = btrfs_del_item(trans, root, path);
1187         if (ret) {
1188                 btrfs_error(root->fs_info, ret,
1189                             "Failed to remove dev extent item");
1190         }
1191 out:
1192         btrfs_free_path(path);
1193         return ret;
1194 }
1195
1196 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1197                            struct btrfs_device *device,
1198                            u64 chunk_tree, u64 chunk_objectid,
1199                            u64 chunk_offset, u64 start, u64 num_bytes)
1200 {
1201         int ret;
1202         struct btrfs_path *path;
1203         struct btrfs_root *root = device->dev_root;
1204         struct btrfs_dev_extent *extent;
1205         struct extent_buffer *leaf;
1206         struct btrfs_key key;
1207
1208         WARN_ON(!device->in_fs_metadata);
1209         WARN_ON(device->is_tgtdev_for_dev_replace);
1210         path = btrfs_alloc_path();
1211         if (!path)
1212                 return -ENOMEM;
1213
1214         key.objectid = device->devid;
1215         key.offset = start;
1216         key.type = BTRFS_DEV_EXTENT_KEY;
1217         ret = btrfs_insert_empty_item(trans, root, path, &key,
1218                                       sizeof(*extent));
1219         if (ret)
1220                 goto out;
1221
1222         leaf = path->nodes[0];
1223         extent = btrfs_item_ptr(leaf, path->slots[0],
1224                                 struct btrfs_dev_extent);
1225         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1226         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1227         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1228
1229         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1230                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1231                     BTRFS_UUID_SIZE);
1232
1233         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1234         btrfs_mark_buffer_dirty(leaf);
1235 out:
1236         btrfs_free_path(path);
1237         return ret;
1238 }
1239
1240 static noinline int find_next_chunk(struct btrfs_root *root,
1241                                     u64 objectid, u64 *offset)
1242 {
1243         struct btrfs_path *path;
1244         int ret;
1245         struct btrfs_key key;
1246         struct btrfs_chunk *chunk;
1247         struct btrfs_key found_key;
1248
1249         path = btrfs_alloc_path();
1250         if (!path)
1251                 return -ENOMEM;
1252
1253         key.objectid = objectid;
1254         key.offset = (u64)-1;
1255         key.type = BTRFS_CHUNK_ITEM_KEY;
1256
1257         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1258         if (ret < 0)
1259                 goto error;
1260
1261         BUG_ON(ret == 0); /* Corruption */
1262
1263         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1264         if (ret) {
1265                 *offset = 0;
1266         } else {
1267                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1268                                       path->slots[0]);
1269                 if (found_key.objectid != objectid)
1270                         *offset = 0;
1271                 else {
1272                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1273                                                struct btrfs_chunk);
1274                         *offset = found_key.offset +
1275                                 btrfs_chunk_length(path->nodes[0], chunk);
1276                 }
1277         }
1278         ret = 0;
1279 error:
1280         btrfs_free_path(path);
1281         return ret;
1282 }
1283
1284 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1285 {
1286         int ret;
1287         struct btrfs_key key;
1288         struct btrfs_key found_key;
1289         struct btrfs_path *path;
1290
1291         root = root->fs_info->chunk_root;
1292
1293         path = btrfs_alloc_path();
1294         if (!path)
1295                 return -ENOMEM;
1296
1297         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1298         key.type = BTRFS_DEV_ITEM_KEY;
1299         key.offset = (u64)-1;
1300
1301         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1302         if (ret < 0)
1303                 goto error;
1304
1305         BUG_ON(ret == 0); /* Corruption */
1306
1307         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1308                                   BTRFS_DEV_ITEM_KEY);
1309         if (ret) {
1310                 *objectid = 1;
1311         } else {
1312                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1313                                       path->slots[0]);
1314                 *objectid = found_key.offset + 1;
1315         }
1316         ret = 0;
1317 error:
1318         btrfs_free_path(path);
1319         return ret;
1320 }
1321
1322 /*
1323  * the device information is stored in the chunk root
1324  * the btrfs_device struct should be fully filled in
1325  */
1326 int btrfs_add_device(struct btrfs_trans_handle *trans,
1327                      struct btrfs_root *root,
1328                      struct btrfs_device *device)
1329 {
1330         int ret;
1331         struct btrfs_path *path;
1332         struct btrfs_dev_item *dev_item;
1333         struct extent_buffer *leaf;
1334         struct btrfs_key key;
1335         unsigned long ptr;
1336
1337         root = root->fs_info->chunk_root;
1338
1339         path = btrfs_alloc_path();
1340         if (!path)
1341                 return -ENOMEM;
1342
1343         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1344         key.type = BTRFS_DEV_ITEM_KEY;
1345         key.offset = device->devid;
1346
1347         ret = btrfs_insert_empty_item(trans, root, path, &key,
1348                                       sizeof(*dev_item));
1349         if (ret)
1350                 goto out;
1351
1352         leaf = path->nodes[0];
1353         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1354
1355         btrfs_set_device_id(leaf, dev_item, device->devid);
1356         btrfs_set_device_generation(leaf, dev_item, 0);
1357         btrfs_set_device_type(leaf, dev_item, device->type);
1358         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1359         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1360         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1361         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1362         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1363         btrfs_set_device_group(leaf, dev_item, 0);
1364         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1365         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1366         btrfs_set_device_start_offset(leaf, dev_item, 0);
1367
1368         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1369         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1370         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1371         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1372         btrfs_mark_buffer_dirty(leaf);
1373
1374         ret = 0;
1375 out:
1376         btrfs_free_path(path);
1377         return ret;
1378 }
1379
1380 static int btrfs_rm_dev_item(struct btrfs_root *root,
1381                              struct btrfs_device *device)
1382 {
1383         int ret;
1384         struct btrfs_path *path;
1385         struct btrfs_key key;
1386         struct btrfs_trans_handle *trans;
1387
1388         root = root->fs_info->chunk_root;
1389
1390         path = btrfs_alloc_path();
1391         if (!path)
1392                 return -ENOMEM;
1393
1394         trans = btrfs_start_transaction(root, 0);
1395         if (IS_ERR(trans)) {
1396                 btrfs_free_path(path);
1397                 return PTR_ERR(trans);
1398         }
1399         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1400         key.type = BTRFS_DEV_ITEM_KEY;
1401         key.offset = device->devid;
1402         lock_chunks(root);
1403
1404         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1405         if (ret < 0)
1406                 goto out;
1407
1408         if (ret > 0) {
1409                 ret = -ENOENT;
1410                 goto out;
1411         }
1412
1413         ret = btrfs_del_item(trans, root, path);
1414         if (ret)
1415                 goto out;
1416 out:
1417         btrfs_free_path(path);
1418         unlock_chunks(root);
1419         btrfs_commit_transaction(trans, root);
1420         return ret;
1421 }
1422
1423 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1424 {
1425         struct btrfs_device *device;
1426         struct btrfs_device *next_device;
1427         struct block_device *bdev;
1428         struct buffer_head *bh = NULL;
1429         struct btrfs_super_block *disk_super;
1430         struct btrfs_fs_devices *cur_devices;
1431         u64 all_avail;
1432         u64 devid;
1433         u64 num_devices;
1434         u8 *dev_uuid;
1435         unsigned seq;
1436         int ret = 0;
1437         bool clear_super = false;
1438
1439         mutex_lock(&uuid_mutex);
1440
1441         do {
1442                 seq = read_seqbegin(&root->fs_info->profiles_lock);
1443
1444                 all_avail = root->fs_info->avail_data_alloc_bits |
1445                             root->fs_info->avail_system_alloc_bits |
1446                             root->fs_info->avail_metadata_alloc_bits;
1447         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
1448
1449         num_devices = root->fs_info->fs_devices->num_devices;
1450         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1451         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1452                 WARN_ON(num_devices < 1);
1453                 num_devices--;
1454         }
1455         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1456
1457         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1458                 printk(KERN_ERR "btrfs: unable to go below four devices "
1459                        "on raid10\n");
1460                 ret = -EINVAL;
1461                 goto out;
1462         }
1463
1464         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1465                 printk(KERN_ERR "btrfs: unable to go below two "
1466                        "devices on raid1\n");
1467                 ret = -EINVAL;
1468                 goto out;
1469         }
1470
1471         if ((all_avail & BTRFS_BLOCK_GROUP_RAID5) &&
1472             root->fs_info->fs_devices->rw_devices <= 2) {
1473                 printk(KERN_ERR "btrfs: unable to go below two "
1474                        "devices on raid5\n");
1475                 ret = -EINVAL;
1476                 goto out;
1477         }
1478         if ((all_avail & BTRFS_BLOCK_GROUP_RAID6) &&
1479             root->fs_info->fs_devices->rw_devices <= 3) {
1480                 printk(KERN_ERR "btrfs: unable to go below three "
1481                        "devices on raid6\n");
1482                 ret = -EINVAL;
1483                 goto out;
1484         }
1485
1486         if (strcmp(device_path, "missing") == 0) {
1487                 struct list_head *devices;
1488                 struct btrfs_device *tmp;
1489
1490                 device = NULL;
1491                 devices = &root->fs_info->fs_devices->devices;
1492                 /*
1493                  * It is safe to read the devices since the volume_mutex
1494                  * is held.
1495                  */
1496                 list_for_each_entry(tmp, devices, dev_list) {
1497                         if (tmp->in_fs_metadata &&
1498                             !tmp->is_tgtdev_for_dev_replace &&
1499                             !tmp->bdev) {
1500                                 device = tmp;
1501                                 break;
1502                         }
1503                 }
1504                 bdev = NULL;
1505                 bh = NULL;
1506                 disk_super = NULL;
1507                 if (!device) {
1508                         printk(KERN_ERR "btrfs: no missing devices found to "
1509                                "remove\n");
1510                         goto out;
1511                 }
1512         } else {
1513                 ret = btrfs_get_bdev_and_sb(device_path,
1514                                             FMODE_WRITE | FMODE_EXCL,
1515                                             root->fs_info->bdev_holder, 0,
1516                                             &bdev, &bh);
1517                 if (ret)
1518                         goto out;
1519                 disk_super = (struct btrfs_super_block *)bh->b_data;
1520                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1521                 dev_uuid = disk_super->dev_item.uuid;
1522                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1523                                            disk_super->fsid);
1524                 if (!device) {
1525                         ret = -ENOENT;
1526                         goto error_brelse;
1527                 }
1528         }
1529
1530         if (device->is_tgtdev_for_dev_replace) {
1531                 pr_err("btrfs: unable to remove the dev_replace target dev\n");
1532                 ret = -EINVAL;
1533                 goto error_brelse;
1534         }
1535
1536         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1537                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1538                        "device\n");
1539                 ret = -EINVAL;
1540                 goto error_brelse;
1541         }
1542
1543         if (device->writeable) {
1544                 lock_chunks(root);
1545                 list_del_init(&device->dev_alloc_list);
1546                 unlock_chunks(root);
1547                 root->fs_info->fs_devices->rw_devices--;
1548                 clear_super = true;
1549         }
1550
1551         ret = btrfs_shrink_device(device, 0);
1552         if (ret)
1553                 goto error_undo;
1554
1555         /*
1556          * TODO: the superblock still includes this device in its num_devices
1557          * counter although write_all_supers() is not locked out. This
1558          * could give a filesystem state which requires a degraded mount.
1559          */
1560         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1561         if (ret)
1562                 goto error_undo;
1563
1564         spin_lock(&root->fs_info->free_chunk_lock);
1565         root->fs_info->free_chunk_space = device->total_bytes -
1566                 device->bytes_used;
1567         spin_unlock(&root->fs_info->free_chunk_lock);
1568
1569         device->in_fs_metadata = 0;
1570         btrfs_scrub_cancel_dev(root->fs_info, device);
1571
1572         /*
1573          * the device list mutex makes sure that we don't change
1574          * the device list while someone else is writing out all
1575          * the device supers.
1576          */
1577
1578         cur_devices = device->fs_devices;
1579         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1580         list_del_rcu(&device->dev_list);
1581
1582         device->fs_devices->num_devices--;
1583         device->fs_devices->total_devices--;
1584
1585         if (device->missing)
1586                 root->fs_info->fs_devices->missing_devices--;
1587
1588         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1589                                  struct btrfs_device, dev_list);
1590         if (device->bdev == root->fs_info->sb->s_bdev)
1591                 root->fs_info->sb->s_bdev = next_device->bdev;
1592         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1593                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1594
1595         if (device->bdev)
1596                 device->fs_devices->open_devices--;
1597
1598         call_rcu(&device->rcu, free_device);
1599         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1600
1601         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1602         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1603
1604         if (cur_devices->open_devices == 0) {
1605                 struct btrfs_fs_devices *fs_devices;
1606                 fs_devices = root->fs_info->fs_devices;
1607                 while (fs_devices) {
1608                         if (fs_devices->seed == cur_devices)
1609                                 break;
1610                         fs_devices = fs_devices->seed;
1611                 }
1612                 fs_devices->seed = cur_devices->seed;
1613                 cur_devices->seed = NULL;
1614                 lock_chunks(root);
1615                 __btrfs_close_devices(cur_devices);
1616                 unlock_chunks(root);
1617                 free_fs_devices(cur_devices);
1618         }
1619
1620         root->fs_info->num_tolerated_disk_barrier_failures =
1621                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1622
1623         /*
1624          * at this point, the device is zero sized.  We want to
1625          * remove it from the devices list and zero out the old super
1626          */
1627         if (clear_super && disk_super) {
1628                 /* make sure this device isn't detected as part of
1629                  * the FS anymore
1630                  */
1631                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1632                 set_buffer_dirty(bh);
1633                 sync_dirty_buffer(bh);
1634         }
1635
1636         ret = 0;
1637
1638         /* Notify udev that device has changed */
1639         if (bdev)
1640                 btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1641
1642 error_brelse:
1643         brelse(bh);
1644         if (bdev)
1645                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1646 out:
1647         mutex_unlock(&uuid_mutex);
1648         return ret;
1649 error_undo:
1650         if (device->writeable) {
1651                 lock_chunks(root);
1652                 list_add(&device->dev_alloc_list,
1653                          &root->fs_info->fs_devices->alloc_list);
1654                 unlock_chunks(root);
1655                 root->fs_info->fs_devices->rw_devices++;
1656         }
1657         goto error_brelse;
1658 }
1659
1660 void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
1661                                  struct btrfs_device *srcdev)
1662 {
1663         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1664         list_del_rcu(&srcdev->dev_list);
1665         list_del_rcu(&srcdev->dev_alloc_list);
1666         fs_info->fs_devices->num_devices--;
1667         if (srcdev->missing) {
1668                 fs_info->fs_devices->missing_devices--;
1669                 fs_info->fs_devices->rw_devices++;
1670         }
1671         if (srcdev->can_discard)
1672                 fs_info->fs_devices->num_can_discard--;
1673         if (srcdev->bdev)
1674                 fs_info->fs_devices->open_devices--;
1675
1676         call_rcu(&srcdev->rcu, free_device);
1677 }
1678
1679 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
1680                                       struct btrfs_device *tgtdev)
1681 {
1682         struct btrfs_device *next_device;
1683
1684         WARN_ON(!tgtdev);
1685         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1686         if (tgtdev->bdev) {
1687                 btrfs_scratch_superblock(tgtdev);
1688                 fs_info->fs_devices->open_devices--;
1689         }
1690         fs_info->fs_devices->num_devices--;
1691         if (tgtdev->can_discard)
1692                 fs_info->fs_devices->num_can_discard++;
1693
1694         next_device = list_entry(fs_info->fs_devices->devices.next,
1695                                  struct btrfs_device, dev_list);
1696         if (tgtdev->bdev == fs_info->sb->s_bdev)
1697                 fs_info->sb->s_bdev = next_device->bdev;
1698         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
1699                 fs_info->fs_devices->latest_bdev = next_device->bdev;
1700         list_del_rcu(&tgtdev->dev_list);
1701
1702         call_rcu(&tgtdev->rcu, free_device);
1703
1704         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1705 }
1706
1707 int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
1708                               struct btrfs_device **device)
1709 {
1710         int ret = 0;
1711         struct btrfs_super_block *disk_super;
1712         u64 devid;
1713         u8 *dev_uuid;
1714         struct block_device *bdev;
1715         struct buffer_head *bh;
1716
1717         *device = NULL;
1718         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
1719                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
1720         if (ret)
1721                 return ret;
1722         disk_super = (struct btrfs_super_block *)bh->b_data;
1723         devid = btrfs_stack_device_id(&disk_super->dev_item);
1724         dev_uuid = disk_super->dev_item.uuid;
1725         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1726                                     disk_super->fsid);
1727         brelse(bh);
1728         if (!*device)
1729                 ret = -ENOENT;
1730         blkdev_put(bdev, FMODE_READ);
1731         return ret;
1732 }
1733
1734 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
1735                                          char *device_path,
1736                                          struct btrfs_device **device)
1737 {
1738         *device = NULL;
1739         if (strcmp(device_path, "missing") == 0) {
1740                 struct list_head *devices;
1741                 struct btrfs_device *tmp;
1742
1743                 devices = &root->fs_info->fs_devices->devices;
1744                 /*
1745                  * It is safe to read the devices since the volume_mutex
1746                  * is held by the caller.
1747                  */
1748                 list_for_each_entry(tmp, devices, dev_list) {
1749                         if (tmp->in_fs_metadata && !tmp->bdev) {
1750                                 *device = tmp;
1751                                 break;
1752                         }
1753                 }
1754
1755                 if (!*device) {
1756                         pr_err("btrfs: no missing device found\n");
1757                         return -ENOENT;
1758                 }
1759
1760                 return 0;
1761         } else {
1762                 return btrfs_find_device_by_path(root, device_path, device);
1763         }
1764 }
1765
1766 /*
1767  * does all the dirty work required for changing file system's UUID.
1768  */
1769 static int btrfs_prepare_sprout(struct btrfs_root *root)
1770 {
1771         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1772         struct btrfs_fs_devices *old_devices;
1773         struct btrfs_fs_devices *seed_devices;
1774         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1775         struct btrfs_device *device;
1776         u64 super_flags;
1777
1778         BUG_ON(!mutex_is_locked(&uuid_mutex));
1779         if (!fs_devices->seeding)
1780                 return -EINVAL;
1781
1782         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1783         if (!seed_devices)
1784                 return -ENOMEM;
1785
1786         old_devices = clone_fs_devices(fs_devices);
1787         if (IS_ERR(old_devices)) {
1788                 kfree(seed_devices);
1789                 return PTR_ERR(old_devices);
1790         }
1791
1792         list_add(&old_devices->list, &fs_uuids);
1793
1794         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1795         seed_devices->opened = 1;
1796         INIT_LIST_HEAD(&seed_devices->devices);
1797         INIT_LIST_HEAD(&seed_devices->alloc_list);
1798         mutex_init(&seed_devices->device_list_mutex);
1799
1800         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1801         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1802                               synchronize_rcu);
1803         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1804
1805         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1806         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1807                 device->fs_devices = seed_devices;
1808         }
1809
1810         fs_devices->seeding = 0;
1811         fs_devices->num_devices = 0;
1812         fs_devices->open_devices = 0;
1813         fs_devices->total_devices = 0;
1814         fs_devices->seed = seed_devices;
1815
1816         generate_random_uuid(fs_devices->fsid);
1817         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1818         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1819         super_flags = btrfs_super_flags(disk_super) &
1820                       ~BTRFS_SUPER_FLAG_SEEDING;
1821         btrfs_set_super_flags(disk_super, super_flags);
1822
1823         return 0;
1824 }
1825
1826 /*
1827  * strore the expected generation for seed devices in device items.
1828  */
1829 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1830                                struct btrfs_root *root)
1831 {
1832         struct btrfs_path *path;
1833         struct extent_buffer *leaf;
1834         struct btrfs_dev_item *dev_item;
1835         struct btrfs_device *device;
1836         struct btrfs_key key;
1837         u8 fs_uuid[BTRFS_UUID_SIZE];
1838         u8 dev_uuid[BTRFS_UUID_SIZE];
1839         u64 devid;
1840         int ret;
1841
1842         path = btrfs_alloc_path();
1843         if (!path)
1844                 return -ENOMEM;
1845
1846         root = root->fs_info->chunk_root;
1847         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1848         key.offset = 0;
1849         key.type = BTRFS_DEV_ITEM_KEY;
1850
1851         while (1) {
1852                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1853                 if (ret < 0)
1854                         goto error;
1855
1856                 leaf = path->nodes[0];
1857 next_slot:
1858                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1859                         ret = btrfs_next_leaf(root, path);
1860                         if (ret > 0)
1861                                 break;
1862                         if (ret < 0)
1863                                 goto error;
1864                         leaf = path->nodes[0];
1865                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1866                         btrfs_release_path(path);
1867                         continue;
1868                 }
1869
1870                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1871                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1872                     key.type != BTRFS_DEV_ITEM_KEY)
1873                         break;
1874
1875                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1876                                           struct btrfs_dev_item);
1877                 devid = btrfs_device_id(leaf, dev_item);
1878                 read_extent_buffer(leaf, dev_uuid,
1879                                    (unsigned long)btrfs_device_uuid(dev_item),
1880                                    BTRFS_UUID_SIZE);
1881                 read_extent_buffer(leaf, fs_uuid,
1882                                    (unsigned long)btrfs_device_fsid(dev_item),
1883                                    BTRFS_UUID_SIZE);
1884                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1885                                            fs_uuid);
1886                 BUG_ON(!device); /* Logic error */
1887
1888                 if (device->fs_devices->seeding) {
1889                         btrfs_set_device_generation(leaf, dev_item,
1890                                                     device->generation);
1891                         btrfs_mark_buffer_dirty(leaf);
1892                 }
1893
1894                 path->slots[0]++;
1895                 goto next_slot;
1896         }
1897         ret = 0;
1898 error:
1899         btrfs_free_path(path);
1900         return ret;
1901 }
1902
1903 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1904 {
1905         struct request_queue *q;
1906         struct btrfs_trans_handle *trans;
1907         struct btrfs_device *device;
1908         struct block_device *bdev;
1909         struct list_head *devices;
1910         struct super_block *sb = root->fs_info->sb;
1911         struct rcu_string *name;
1912         u64 total_bytes;
1913         int seeding_dev = 0;
1914         int ret = 0;
1915
1916         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1917                 return -EROFS;
1918
1919         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1920                                   root->fs_info->bdev_holder);
1921         if (IS_ERR(bdev))
1922                 return PTR_ERR(bdev);
1923
1924         if (root->fs_info->fs_devices->seeding) {
1925                 seeding_dev = 1;
1926                 down_write(&sb->s_umount);
1927                 mutex_lock(&uuid_mutex);
1928         }
1929
1930         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1931
1932         devices = &root->fs_info->fs_devices->devices;
1933
1934         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1935         list_for_each_entry(device, devices, dev_list) {
1936                 if (device->bdev == bdev) {
1937                         ret = -EEXIST;
1938                         mutex_unlock(
1939                                 &root->fs_info->fs_devices->device_list_mutex);
1940                         goto error;
1941                 }
1942         }
1943         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1944
1945         device = kzalloc(sizeof(*device), GFP_NOFS);
1946         if (!device) {
1947                 /* we can safely leave the fs_devices entry around */
1948                 ret = -ENOMEM;
1949                 goto error;
1950         }
1951
1952         name = rcu_string_strdup(device_path, GFP_NOFS);
1953         if (!name) {
1954                 kfree(device);
1955                 ret = -ENOMEM;
1956                 goto error;
1957         }
1958         rcu_assign_pointer(device->name, name);
1959
1960         ret = find_next_devid(root, &device->devid);
1961         if (ret) {
1962                 rcu_string_free(device->name);
1963                 kfree(device);
1964                 goto error;
1965         }
1966
1967         trans = btrfs_start_transaction(root, 0);
1968         if (IS_ERR(trans)) {
1969                 rcu_string_free(device->name);
1970                 kfree(device);
1971                 ret = PTR_ERR(trans);
1972                 goto error;
1973         }
1974
1975         lock_chunks(root);
1976
1977         q = bdev_get_queue(bdev);
1978         if (blk_queue_discard(q))
1979                 device->can_discard = 1;
1980         device->writeable = 1;
1981         device->work.func = pending_bios_fn;
1982         generate_random_uuid(device->uuid);
1983         spin_lock_init(&device->io_lock);
1984         device->generation = trans->transid;
1985         device->io_width = root->sectorsize;
1986         device->io_align = root->sectorsize;
1987         device->sector_size = root->sectorsize;
1988         device->total_bytes = i_size_read(bdev->bd_inode);
1989         device->disk_total_bytes = device->total_bytes;
1990         device->dev_root = root->fs_info->dev_root;
1991         device->bdev = bdev;
1992         device->in_fs_metadata = 1;
1993         device->is_tgtdev_for_dev_replace = 0;
1994         device->mode = FMODE_EXCL;
1995         set_blocksize(device->bdev, 4096);
1996
1997         if (seeding_dev) {
1998                 sb->s_flags &= ~MS_RDONLY;
1999                 ret = btrfs_prepare_sprout(root);
2000                 BUG_ON(ret); /* -ENOMEM */
2001         }
2002
2003         device->fs_devices = root->fs_info->fs_devices;
2004
2005         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2006         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
2007         list_add(&device->dev_alloc_list,
2008                  &root->fs_info->fs_devices->alloc_list);
2009         root->fs_info->fs_devices->num_devices++;
2010         root->fs_info->fs_devices->open_devices++;
2011         root->fs_info->fs_devices->rw_devices++;
2012         root->fs_info->fs_devices->total_devices++;
2013         if (device->can_discard)
2014                 root->fs_info->fs_devices->num_can_discard++;
2015         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
2016
2017         spin_lock(&root->fs_info->free_chunk_lock);
2018         root->fs_info->free_chunk_space += device->total_bytes;
2019         spin_unlock(&root->fs_info->free_chunk_lock);
2020
2021         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
2022                 root->fs_info->fs_devices->rotating = 1;
2023
2024         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
2025         btrfs_set_super_total_bytes(root->fs_info->super_copy,
2026                                     total_bytes + device->total_bytes);
2027
2028         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
2029         btrfs_set_super_num_devices(root->fs_info->super_copy,
2030                                     total_bytes + 1);
2031         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2032
2033         if (seeding_dev) {
2034                 ret = init_first_rw_device(trans, root, device);
2035                 if (ret) {
2036                         btrfs_abort_transaction(trans, root, ret);
2037                         goto error_trans;
2038                 }
2039                 ret = btrfs_finish_sprout(trans, root);
2040                 if (ret) {
2041                         btrfs_abort_transaction(trans, root, ret);
2042                         goto error_trans;
2043                 }
2044         } else {
2045                 ret = btrfs_add_device(trans, root, device);
2046                 if (ret) {
2047                         btrfs_abort_transaction(trans, root, ret);
2048                         goto error_trans;
2049                 }
2050         }
2051
2052         /*
2053          * we've got more storage, clear any full flags on the space
2054          * infos
2055          */
2056         btrfs_clear_space_info_full(root->fs_info);
2057
2058         unlock_chunks(root);
2059         root->fs_info->num_tolerated_disk_barrier_failures =
2060                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
2061         ret = btrfs_commit_transaction(trans, root);
2062
2063         if (seeding_dev) {
2064                 mutex_unlock(&uuid_mutex);
2065                 up_write(&sb->s_umount);
2066
2067                 if (ret) /* transaction commit */
2068                         return ret;
2069
2070                 ret = btrfs_relocate_sys_chunks(root);
2071                 if (ret < 0)
2072                         btrfs_error(root->fs_info, ret,
2073                                     "Failed to relocate sys chunks after "
2074                                     "device initialization. This can be fixed "
2075                                     "using the \"btrfs balance\" command.");
2076                 trans = btrfs_attach_transaction(root);
2077                 if (IS_ERR(trans)) {
2078                         if (PTR_ERR(trans) == -ENOENT)
2079                                 return 0;
2080                         return PTR_ERR(trans);
2081                 }
2082                 ret = btrfs_commit_transaction(trans, root);
2083         }
2084
2085         return ret;
2086
2087 error_trans:
2088         unlock_chunks(root);
2089         btrfs_end_transaction(trans, root);
2090         rcu_string_free(device->name);
2091         kfree(device);
2092 error:
2093         blkdev_put(bdev, FMODE_EXCL);
2094         if (seeding_dev) {
2095                 mutex_unlock(&uuid_mutex);
2096                 up_write(&sb->s_umount);
2097         }
2098         return ret;
2099 }
2100
2101 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2102                                   struct btrfs_device **device_out)
2103 {
2104         struct request_queue *q;
2105         struct btrfs_device *device;
2106         struct block_device *bdev;
2107         struct btrfs_fs_info *fs_info = root->fs_info;
2108         struct list_head *devices;
2109         struct rcu_string *name;
2110         int ret = 0;
2111
2112         *device_out = NULL;
2113         if (fs_info->fs_devices->seeding)
2114                 return -EINVAL;
2115
2116         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2117                                   fs_info->bdev_holder);
2118         if (IS_ERR(bdev))
2119                 return PTR_ERR(bdev);
2120
2121         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2122
2123         devices = &fs_info->fs_devices->devices;
2124         list_for_each_entry(device, devices, dev_list) {
2125                 if (device->bdev == bdev) {
2126                         ret = -EEXIST;
2127                         goto error;
2128                 }
2129         }
2130
2131         device = kzalloc(sizeof(*device), GFP_NOFS);
2132         if (!device) {
2133                 ret = -ENOMEM;
2134                 goto error;
2135         }
2136
2137         name = rcu_string_strdup(device_path, GFP_NOFS);
2138         if (!name) {
2139                 kfree(device);
2140                 ret = -ENOMEM;
2141                 goto error;
2142         }
2143         rcu_assign_pointer(device->name, name);
2144
2145         q = bdev_get_queue(bdev);
2146         if (blk_queue_discard(q))
2147                 device->can_discard = 1;
2148         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2149         device->writeable = 1;
2150         device->work.func = pending_bios_fn;
2151         generate_random_uuid(device->uuid);
2152         device->devid = BTRFS_DEV_REPLACE_DEVID;
2153         spin_lock_init(&device->io_lock);
2154         device->generation = 0;
2155         device->io_width = root->sectorsize;
2156         device->io_align = root->sectorsize;
2157         device->sector_size = root->sectorsize;
2158         device->total_bytes = i_size_read(bdev->bd_inode);
2159         device->disk_total_bytes = device->total_bytes;
2160         device->dev_root = fs_info->dev_root;
2161         device->bdev = bdev;
2162         device->in_fs_metadata = 1;
2163         device->is_tgtdev_for_dev_replace = 1;
2164         device->mode = FMODE_EXCL;
2165         set_blocksize(device->bdev, 4096);
2166         device->fs_devices = fs_info->fs_devices;
2167         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2168         fs_info->fs_devices->num_devices++;
2169         fs_info->fs_devices->open_devices++;
2170         if (device->can_discard)
2171                 fs_info->fs_devices->num_can_discard++;
2172         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2173
2174         *device_out = device;
2175         return ret;
2176
2177 error:
2178         blkdev_put(bdev, FMODE_EXCL);
2179         return ret;
2180 }
2181
2182 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2183                                               struct btrfs_device *tgtdev)
2184 {
2185         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2186         tgtdev->io_width = fs_info->dev_root->sectorsize;
2187         tgtdev->io_align = fs_info->dev_root->sectorsize;
2188         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2189         tgtdev->dev_root = fs_info->dev_root;
2190         tgtdev->in_fs_metadata = 1;
2191 }
2192
2193 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2194                                         struct btrfs_device *device)
2195 {
2196         int ret;
2197         struct btrfs_path *path;
2198         struct btrfs_root *root;
2199         struct btrfs_dev_item *dev_item;
2200         struct extent_buffer *leaf;
2201         struct btrfs_key key;
2202
2203         root = device->dev_root->fs_info->chunk_root;
2204
2205         path = btrfs_alloc_path();
2206         if (!path)
2207                 return -ENOMEM;
2208
2209         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2210         key.type = BTRFS_DEV_ITEM_KEY;
2211         key.offset = device->devid;
2212
2213         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2214         if (ret < 0)
2215                 goto out;
2216
2217         if (ret > 0) {
2218                 ret = -ENOENT;
2219                 goto out;
2220         }
2221
2222         leaf = path->nodes[0];
2223         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2224
2225         btrfs_set_device_id(leaf, dev_item, device->devid);
2226         btrfs_set_device_type(leaf, dev_item, device->type);
2227         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2228         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2229         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2230         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
2231         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
2232         btrfs_mark_buffer_dirty(leaf);
2233
2234 out:
2235         btrfs_free_path(path);
2236         return ret;
2237 }
2238
2239 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
2240                       struct btrfs_device *device, u64 new_size)
2241 {
2242         struct btrfs_super_block *super_copy =
2243                 device->dev_root->fs_info->super_copy;
2244         u64 old_total = btrfs_super_total_bytes(super_copy);
2245         u64 diff = new_size - device->total_bytes;
2246
2247         if (!device->writeable)
2248                 return -EACCES;
2249         if (new_size <= device->total_bytes ||
2250             device->is_tgtdev_for_dev_replace)
2251                 return -EINVAL;
2252
2253         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2254         device->fs_devices->total_rw_bytes += diff;
2255
2256         device->total_bytes = new_size;
2257         device->disk_total_bytes = new_size;
2258         btrfs_clear_space_info_full(device->dev_root->fs_info);
2259
2260         return btrfs_update_device(trans, device);
2261 }
2262
2263 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2264                       struct btrfs_device *device, u64 new_size)
2265 {
2266         int ret;
2267         lock_chunks(device->dev_root);
2268         ret = __btrfs_grow_device(trans, device, new_size);
2269         unlock_chunks(device->dev_root);
2270         return ret;
2271 }
2272
2273 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2274                             struct btrfs_root *root,
2275                             u64 chunk_tree, u64 chunk_objectid,
2276                             u64 chunk_offset)
2277 {
2278         int ret;
2279         struct btrfs_path *path;
2280         struct btrfs_key key;
2281
2282         root = root->fs_info->chunk_root;
2283         path = btrfs_alloc_path();
2284         if (!path)
2285                 return -ENOMEM;
2286
2287         key.objectid = chunk_objectid;
2288         key.offset = chunk_offset;
2289         key.type = BTRFS_CHUNK_ITEM_KEY;
2290
2291         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2292         if (ret < 0)
2293                 goto out;
2294         else if (ret > 0) { /* Logic error or corruption */
2295                 btrfs_error(root->fs_info, -ENOENT,
2296                             "Failed lookup while freeing chunk.");
2297                 ret = -ENOENT;
2298                 goto out;
2299         }
2300
2301         ret = btrfs_del_item(trans, root, path);
2302         if (ret < 0)
2303                 btrfs_error(root->fs_info, ret,
2304                             "Failed to delete chunk item.");
2305 out:
2306         btrfs_free_path(path);
2307         return ret;
2308 }
2309
2310 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2311                         chunk_offset)
2312 {
2313         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2314         struct btrfs_disk_key *disk_key;
2315         struct btrfs_chunk *chunk;
2316         u8 *ptr;
2317         int ret = 0;
2318         u32 num_stripes;
2319         u32 array_size;
2320         u32 len = 0;
2321         u32 cur;
2322         struct btrfs_key key;
2323
2324         array_size = btrfs_super_sys_array_size(super_copy);
2325
2326         ptr = super_copy->sys_chunk_array;
2327         cur = 0;
2328
2329         while (cur < array_size) {
2330                 disk_key = (struct btrfs_disk_key *)ptr;
2331                 btrfs_disk_key_to_cpu(&key, disk_key);
2332
2333                 len = sizeof(*disk_key);
2334
2335                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2336                         chunk = (struct btrfs_chunk *)(ptr + len);
2337                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2338                         len += btrfs_chunk_item_size(num_stripes);
2339                 } else {
2340                         ret = -EIO;
2341                         break;
2342                 }
2343                 if (key.objectid == chunk_objectid &&
2344                     key.offset == chunk_offset) {
2345                         memmove(ptr, ptr + len, array_size - (cur + len));
2346                         array_size -= len;
2347                         btrfs_set_super_sys_array_size(super_copy, array_size);
2348                 } else {
2349                         ptr += len;
2350                         cur += len;
2351                 }
2352         }
2353         return ret;
2354 }
2355
2356 static int btrfs_relocate_chunk(struct btrfs_root *root,
2357                          u64 chunk_tree, u64 chunk_objectid,
2358                          u64 chunk_offset)
2359 {
2360         struct extent_map_tree *em_tree;
2361         struct btrfs_root *extent_root;
2362         struct btrfs_trans_handle *trans;
2363         struct extent_map *em;
2364         struct map_lookup *map;
2365         int ret;
2366         int i;
2367
2368         root = root->fs_info->chunk_root;
2369         extent_root = root->fs_info->extent_root;
2370         em_tree = &root->fs_info->mapping_tree.map_tree;
2371
2372         ret = btrfs_can_relocate(extent_root, chunk_offset);
2373         if (ret)
2374                 return -ENOSPC;
2375
2376         /* step one, relocate all the extents inside this chunk */
2377         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2378         if (ret)
2379                 return ret;
2380
2381         trans = btrfs_start_transaction(root, 0);
2382         if (IS_ERR(trans)) {
2383                 ret = PTR_ERR(trans);
2384                 btrfs_std_error(root->fs_info, ret);
2385                 return ret;
2386         }
2387
2388         lock_chunks(root);
2389
2390         /*
2391          * step two, delete the device extents and the
2392          * chunk tree entries
2393          */
2394         read_lock(&em_tree->lock);
2395         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2396         read_unlock(&em_tree->lock);
2397
2398         BUG_ON(!em || em->start > chunk_offset ||
2399                em->start + em->len < chunk_offset);
2400         map = (struct map_lookup *)em->bdev;
2401
2402         for (i = 0; i < map->num_stripes; i++) {
2403                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2404                                             map->stripes[i].physical);
2405                 BUG_ON(ret);
2406
2407                 if (map->stripes[i].dev) {
2408                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2409                         BUG_ON(ret);
2410                 }
2411         }
2412         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2413                                chunk_offset);
2414
2415         BUG_ON(ret);
2416
2417         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2418
2419         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2420                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2421                 BUG_ON(ret);
2422         }
2423
2424         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2425         BUG_ON(ret);
2426
2427         write_lock(&em_tree->lock);
2428         remove_extent_mapping(em_tree, em);
2429         write_unlock(&em_tree->lock);
2430
2431         kfree(map);
2432         em->bdev = NULL;
2433
2434         /* once for the tree */
2435         free_extent_map(em);
2436         /* once for us */
2437         free_extent_map(em);
2438
2439         unlock_chunks(root);
2440         btrfs_end_transaction(trans, root);
2441         return 0;
2442 }
2443
2444 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2445 {
2446         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2447         struct btrfs_path *path;
2448         struct extent_buffer *leaf;
2449         struct btrfs_chunk *chunk;
2450         struct btrfs_key key;
2451         struct btrfs_key found_key;
2452         u64 chunk_tree = chunk_root->root_key.objectid;
2453         u64 chunk_type;
2454         bool retried = false;
2455         int failed = 0;
2456         int ret;
2457
2458         path = btrfs_alloc_path();
2459         if (!path)
2460                 return -ENOMEM;
2461
2462 again:
2463         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2464         key.offset = (u64)-1;
2465         key.type = BTRFS_CHUNK_ITEM_KEY;
2466
2467         while (1) {
2468                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2469                 if (ret < 0)
2470                         goto error;
2471                 BUG_ON(ret == 0); /* Corruption */
2472
2473                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2474                                           key.type);
2475                 if (ret < 0)
2476                         goto error;
2477                 if (ret > 0)
2478                         break;
2479
2480                 leaf = path->nodes[0];
2481                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2482
2483                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2484                                        struct btrfs_chunk);
2485                 chunk_type = btrfs_chunk_type(leaf, chunk);
2486                 btrfs_release_path(path);
2487
2488                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2489                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2490                                                    found_key.objectid,
2491                                                    found_key.offset);
2492                         if (ret == -ENOSPC)
2493                                 failed++;
2494                         else if (ret)
2495                                 BUG();
2496                 }
2497
2498                 if (found_key.offset == 0)
2499                         break;
2500                 key.offset = found_key.offset - 1;
2501         }
2502         ret = 0;
2503         if (failed && !retried) {
2504                 failed = 0;
2505                 retried = true;
2506                 goto again;
2507         } else if (failed && retried) {
2508                 WARN_ON(1);
2509                 ret = -ENOSPC;
2510         }
2511 error:
2512         btrfs_free_path(path);
2513         return ret;
2514 }
2515
2516 static int insert_balance_item(struct btrfs_root *root,
2517                                struct btrfs_balance_control *bctl)
2518 {
2519         struct btrfs_trans_handle *trans;
2520         struct btrfs_balance_item *item;
2521         struct btrfs_disk_balance_args disk_bargs;
2522         struct btrfs_path *path;
2523         struct extent_buffer *leaf;
2524         struct btrfs_key key;
2525         int ret, err;
2526
2527         path = btrfs_alloc_path();
2528         if (!path)
2529                 return -ENOMEM;
2530
2531         trans = btrfs_start_transaction(root, 0);
2532         if (IS_ERR(trans)) {
2533                 btrfs_free_path(path);
2534                 return PTR_ERR(trans);
2535         }
2536
2537         key.objectid = BTRFS_BALANCE_OBJECTID;
2538         key.type = BTRFS_BALANCE_ITEM_KEY;
2539         key.offset = 0;
2540
2541         ret = btrfs_insert_empty_item(trans, root, path, &key,
2542                                       sizeof(*item));
2543         if (ret)
2544                 goto out;
2545
2546         leaf = path->nodes[0];
2547         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2548
2549         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2550
2551         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2552         btrfs_set_balance_data(leaf, item, &disk_bargs);
2553         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2554         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2555         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2556         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2557
2558         btrfs_set_balance_flags(leaf, item, bctl->flags);
2559
2560         btrfs_mark_buffer_dirty(leaf);
2561 out:
2562         btrfs_free_path(path);
2563         err = btrfs_commit_transaction(trans, root);
2564         if (err && !ret)
2565                 ret = err;
2566         return ret;
2567 }
2568
2569 static int del_balance_item(struct btrfs_root *root)
2570 {
2571         struct btrfs_trans_handle *trans;
2572         struct btrfs_path *path;
2573         struct btrfs_key key;
2574         int ret, err;
2575
2576         path = btrfs_alloc_path();
2577         if (!path)
2578                 return -ENOMEM;
2579
2580         trans = btrfs_start_transaction(root, 0);
2581         if (IS_ERR(trans)) {
2582                 btrfs_free_path(path);
2583                 return PTR_ERR(trans);
2584         }
2585
2586         key.objectid = BTRFS_BALANCE_OBJECTID;
2587         key.type = BTRFS_BALANCE_ITEM_KEY;
2588         key.offset = 0;
2589
2590         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2591         if (ret < 0)
2592                 goto out;
2593         if (ret > 0) {
2594                 ret = -ENOENT;
2595                 goto out;
2596         }
2597
2598         ret = btrfs_del_item(trans, root, path);
2599 out:
2600         btrfs_free_path(path);
2601         err = btrfs_commit_transaction(trans, root);
2602         if (err && !ret)
2603                 ret = err;
2604         return ret;
2605 }
2606
2607 /*
2608  * This is a heuristic used to reduce the number of chunks balanced on
2609  * resume after balance was interrupted.
2610  */
2611 static void update_balance_args(struct btrfs_balance_control *bctl)
2612 {
2613         /*
2614          * Turn on soft mode for chunk types that were being converted.
2615          */
2616         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2617                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2618         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2619                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2620         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2621                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2622
2623         /*
2624          * Turn on usage filter if is not already used.  The idea is
2625          * that chunks that we have already balanced should be
2626          * reasonably full.  Don't do it for chunks that are being
2627          * converted - that will keep us from relocating unconverted
2628          * (albeit full) chunks.
2629          */
2630         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2631             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2632                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2633                 bctl->data.usage = 90;
2634         }
2635         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2636             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2637                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2638                 bctl->sys.usage = 90;
2639         }
2640         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2641             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2642                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2643                 bctl->meta.usage = 90;
2644         }
2645 }
2646
2647 /*
2648  * Should be called with both balance and volume mutexes held to
2649  * serialize other volume operations (add_dev/rm_dev/resize) with
2650  * restriper.  Same goes for unset_balance_control.
2651  */
2652 static void set_balance_control(struct btrfs_balance_control *bctl)
2653 {
2654         struct btrfs_fs_info *fs_info = bctl->fs_info;
2655
2656         BUG_ON(fs_info->balance_ctl);
2657
2658         spin_lock(&fs_info->balance_lock);
2659         fs_info->balance_ctl = bctl;
2660         spin_unlock(&fs_info->balance_lock);
2661 }
2662
2663 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2664 {
2665         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2666
2667         BUG_ON(!fs_info->balance_ctl);
2668
2669         spin_lock(&fs_info->balance_lock);
2670         fs_info->balance_ctl = NULL;
2671         spin_unlock(&fs_info->balance_lock);
2672
2673         kfree(bctl);
2674 }
2675
2676 /*
2677  * Balance filters.  Return 1 if chunk should be filtered out
2678  * (should not be balanced).
2679  */
2680 static int chunk_profiles_filter(u64 chunk_type,
2681                                  struct btrfs_balance_args *bargs)
2682 {
2683         chunk_type = chunk_to_extended(chunk_type) &
2684                                 BTRFS_EXTENDED_PROFILE_MASK;
2685
2686         if (bargs->profiles & chunk_type)
2687                 return 0;
2688
2689         return 1;
2690 }
2691
2692 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2693                               struct btrfs_balance_args *bargs)
2694 {
2695         struct btrfs_block_group_cache *cache;
2696         u64 chunk_used, user_thresh;
2697         int ret = 1;
2698
2699         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2700         chunk_used = btrfs_block_group_used(&cache->item);
2701
2702         if (bargs->usage == 0)
2703                 user_thresh = 1;
2704         else if (bargs->usage > 100)
2705                 user_thresh = cache->key.offset;
2706         else
2707                 user_thresh = div_factor_fine(cache->key.offset,
2708                                               bargs->usage);
2709
2710         if (chunk_used < user_thresh)
2711                 ret = 0;
2712
2713         btrfs_put_block_group(cache);
2714         return ret;
2715 }
2716
2717 static int chunk_devid_filter(struct extent_buffer *leaf,
2718                               struct btrfs_chunk *chunk,
2719                               struct btrfs_balance_args *bargs)
2720 {
2721         struct btrfs_stripe *stripe;
2722         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2723         int i;
2724
2725         for (i = 0; i < num_stripes; i++) {
2726                 stripe = btrfs_stripe_nr(chunk, i);
2727                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2728                         return 0;
2729         }
2730
2731         return 1;
2732 }
2733
2734 /* [pstart, pend) */
2735 static int chunk_drange_filter(struct extent_buffer *leaf,
2736                                struct btrfs_chunk *chunk,
2737                                u64 chunk_offset,
2738                                struct btrfs_balance_args *bargs)
2739 {
2740         struct btrfs_stripe *stripe;
2741         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2742         u64 stripe_offset;
2743         u64 stripe_length;
2744         int factor;
2745         int i;
2746
2747         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2748                 return 0;
2749
2750         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2751              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
2752                 factor = num_stripes / 2;
2753         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
2754                 factor = num_stripes - 1;
2755         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
2756                 factor = num_stripes - 2;
2757         } else {
2758                 factor = num_stripes;
2759         }
2760
2761         for (i = 0; i < num_stripes; i++) {
2762                 stripe = btrfs_stripe_nr(chunk, i);
2763                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2764                         continue;
2765
2766                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
2767                 stripe_length = btrfs_chunk_length(leaf, chunk);
2768                 do_div(stripe_length, factor);
2769
2770                 if (stripe_offset < bargs->pend &&
2771                     stripe_offset + stripe_length > bargs->pstart)
2772                         return 0;
2773         }
2774
2775         return 1;
2776 }
2777
2778 /* [vstart, vend) */
2779 static int chunk_vrange_filter(struct extent_buffer *leaf,
2780                                struct btrfs_chunk *chunk,
2781                                u64 chunk_offset,
2782                                struct btrfs_balance_args *bargs)
2783 {
2784         if (chunk_offset < bargs->vend &&
2785             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2786                 /* at least part of the chunk is inside this vrange */
2787                 return 0;
2788
2789         return 1;
2790 }
2791
2792 static int chunk_soft_convert_filter(u64 chunk_type,
2793                                      struct btrfs_balance_args *bargs)
2794 {
2795         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2796                 return 0;
2797
2798         chunk_type = chunk_to_extended(chunk_type) &
2799                                 BTRFS_EXTENDED_PROFILE_MASK;
2800
2801         if (bargs->target == chunk_type)
2802                 return 1;
2803
2804         return 0;
2805 }
2806
2807 static int should_balance_chunk(struct btrfs_root *root,
2808                                 struct extent_buffer *leaf,
2809                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2810 {
2811         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2812         struct btrfs_balance_args *bargs = NULL;
2813         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2814
2815         /* type filter */
2816         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2817               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2818                 return 0;
2819         }
2820
2821         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2822                 bargs = &bctl->data;
2823         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2824                 bargs = &bctl->sys;
2825         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2826                 bargs = &bctl->meta;
2827
2828         /* profiles filter */
2829         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2830             chunk_profiles_filter(chunk_type, bargs)) {
2831                 return 0;
2832         }
2833
2834         /* usage filter */
2835         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2836             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2837                 return 0;
2838         }
2839
2840         /* devid filter */
2841         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2842             chunk_devid_filter(leaf, chunk, bargs)) {
2843                 return 0;
2844         }
2845
2846         /* drange filter, makes sense only with devid filter */
2847         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2848             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2849                 return 0;
2850         }
2851
2852         /* vrange filter */
2853         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2854             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2855                 return 0;
2856         }
2857
2858         /* soft profile changing mode */
2859         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2860             chunk_soft_convert_filter(chunk_type, bargs)) {
2861                 return 0;
2862         }
2863
2864         return 1;
2865 }
2866
2867 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2868 {
2869         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2870         struct btrfs_root *chunk_root = fs_info->chunk_root;
2871         struct btrfs_root *dev_root = fs_info->dev_root;
2872         struct list_head *devices;
2873         struct btrfs_device *device;
2874         u64 old_size;
2875         u64 size_to_free;
2876         struct btrfs_chunk *chunk;
2877         struct btrfs_path *path;
2878         struct btrfs_key key;
2879         struct btrfs_key found_key;
2880         struct btrfs_trans_handle *trans;
2881         struct extent_buffer *leaf;
2882         int slot;
2883         int ret;
2884         int enospc_errors = 0;
2885         bool counting = true;
2886
2887         /* step one make some room on all the devices */
2888         devices = &fs_info->fs_devices->devices;
2889         list_for_each_entry(device, devices, dev_list) {
2890                 old_size = device->total_bytes;
2891                 size_to_free = div_factor(old_size, 1);
2892                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2893                 if (!device->writeable ||
2894                     device->total_bytes - device->bytes_used > size_to_free ||
2895                     device->is_tgtdev_for_dev_replace)
2896                         continue;
2897
2898                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2899                 if (ret == -ENOSPC)
2900                         break;
2901                 BUG_ON(ret);
2902
2903                 trans = btrfs_start_transaction(dev_root, 0);
2904                 BUG_ON(IS_ERR(trans));
2905
2906                 ret = btrfs_grow_device(trans, device, old_size);
2907                 BUG_ON(ret);
2908
2909                 btrfs_end_transaction(trans, dev_root);
2910         }
2911
2912         /* step two, relocate all the chunks */
2913         path = btrfs_alloc_path();
2914         if (!path) {
2915                 ret = -ENOMEM;
2916                 goto error;
2917         }
2918
2919         /* zero out stat counters */
2920         spin_lock(&fs_info->balance_lock);
2921         memset(&bctl->stat, 0, sizeof(bctl->stat));
2922         spin_unlock(&fs_info->balance_lock);
2923 again:
2924         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2925         key.offset = (u64)-1;
2926         key.type = BTRFS_CHUNK_ITEM_KEY;
2927
2928         while (1) {
2929                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2930                     atomic_read(&fs_info->balance_cancel_req)) {
2931                         ret = -ECANCELED;
2932                         goto error;
2933                 }
2934
2935                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2936                 if (ret < 0)
2937                         goto error;
2938
2939                 /*
2940                  * this shouldn't happen, it means the last relocate
2941                  * failed
2942                  */
2943                 if (ret == 0)
2944                         BUG(); /* FIXME break ? */
2945
2946                 ret = btrfs_previous_item(chunk_root, path, 0,
2947                                           BTRFS_CHUNK_ITEM_KEY);
2948                 if (ret) {
2949                         ret = 0;
2950                         break;
2951                 }
2952
2953                 leaf = path->nodes[0];
2954                 slot = path->slots[0];
2955                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2956
2957                 if (found_key.objectid != key.objectid)
2958                         break;
2959
2960                 /* chunk zero is special */
2961                 if (found_key.offset == 0)
2962                         break;
2963
2964                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2965
2966                 if (!counting) {
2967                         spin_lock(&fs_info->balance_lock);
2968                         bctl->stat.considered++;
2969                         spin_unlock(&fs_info->balance_lock);
2970                 }
2971
2972                 ret = should_balance_chunk(chunk_root, leaf, chunk,
2973                                            found_key.offset);
2974                 btrfs_release_path(path);
2975                 if (!ret)
2976                         goto loop;
2977
2978                 if (counting) {
2979                         spin_lock(&fs_info->balance_lock);
2980                         bctl->stat.expected++;
2981                         spin_unlock(&fs_info->balance_lock);
2982                         goto loop;
2983                 }
2984
2985                 ret = btrfs_relocate_chunk(chunk_root,
2986                                            chunk_root->root_key.objectid,
2987                                            found_key.objectid,
2988                                            found_key.offset);
2989                 if (ret && ret != -ENOSPC)
2990                         goto error;
2991                 if (ret == -ENOSPC) {
2992                         enospc_errors++;
2993                 } else {
2994                         spin_lock(&fs_info->balance_lock);
2995                         bctl->stat.completed++;
2996                         spin_unlock(&fs_info->balance_lock);
2997                 }
2998 loop:
2999                 key.offset = found_key.offset - 1;
3000         }
3001
3002         if (counting) {
3003                 btrfs_release_path(path);
3004                 counting = false;
3005                 goto again;
3006         }
3007 error:
3008         btrfs_free_path(path);
3009         if (enospc_errors) {
3010                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
3011                        enospc_errors);
3012                 if (!ret)
3013                         ret = -ENOSPC;
3014         }
3015
3016         return ret;
3017 }
3018
3019 /**
3020  * alloc_profile_is_valid - see if a given profile is valid and reduced
3021  * @flags: profile to validate
3022  * @extended: if true @flags is treated as an extended profile
3023  */
3024 static int alloc_profile_is_valid(u64 flags, int extended)
3025 {
3026         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
3027                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
3028
3029         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
3030
3031         /* 1) check that all other bits are zeroed */
3032         if (flags & ~mask)
3033                 return 0;
3034
3035         /* 2) see if profile is reduced */
3036         if (flags == 0)
3037                 return !extended; /* "0" is valid for usual profiles */
3038
3039         /* true if exactly one bit set */
3040         return (flags & (flags - 1)) == 0;
3041 }
3042
3043 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
3044 {
3045         /* cancel requested || normal exit path */
3046         return atomic_read(&fs_info->balance_cancel_req) ||
3047                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
3048                  atomic_read(&fs_info->balance_cancel_req) == 0);
3049 }
3050
3051 static void __cancel_balance(struct btrfs_fs_info *fs_info)
3052 {
3053         int ret;
3054
3055         unset_balance_control(fs_info);
3056         ret = del_balance_item(fs_info->tree_root);
3057         if (ret)
3058                 btrfs_std_error(fs_info, ret);
3059
3060         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3061 }
3062
3063 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
3064                                struct btrfs_ioctl_balance_args *bargs);
3065
3066 /*
3067  * Should be called with both balance and volume mutexes held
3068  */
3069 int btrfs_balance(struct btrfs_balance_control *bctl,
3070                   struct btrfs_ioctl_balance_args *bargs)
3071 {
3072         struct btrfs_fs_info *fs_info = bctl->fs_info;
3073         u64 allowed;
3074         int mixed = 0;
3075         int ret;
3076         u64 num_devices;
3077         unsigned seq;
3078
3079         if (btrfs_fs_closing(fs_info) ||
3080             atomic_read(&fs_info->balance_pause_req) ||
3081             atomic_read(&fs_info->balance_cancel_req)) {
3082                 ret = -EINVAL;
3083                 goto out;
3084         }
3085
3086         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
3087         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
3088                 mixed = 1;
3089
3090         /*
3091          * In case of mixed groups both data and meta should be picked,
3092          * and identical options should be given for both of them.
3093          */
3094         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3095         if (mixed && (bctl->flags & allowed)) {
3096                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3097                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3098                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3099                         printk(KERN_ERR "btrfs: with mixed groups data and "
3100                                "metadata balance options must be the same\n");
3101                         ret = -EINVAL;
3102                         goto out;
3103                 }
3104         }
3105
3106         num_devices = fs_info->fs_devices->num_devices;
3107         btrfs_dev_replace_lock(&fs_info->dev_replace);
3108         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3109                 BUG_ON(num_devices < 1);
3110                 num_devices--;
3111         }
3112         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3113         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3114         if (num_devices == 1)
3115                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3116         else if (num_devices < 4)
3117                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3118         else
3119                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
3120                                 BTRFS_BLOCK_GROUP_RAID10 |
3121                                 BTRFS_BLOCK_GROUP_RAID5 |
3122                                 BTRFS_BLOCK_GROUP_RAID6);
3123
3124         if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3125             (!alloc_profile_is_valid(bctl->data.target, 1) ||
3126              (bctl->data.target & ~allowed))) {
3127                 printk(KERN_ERR "btrfs: unable to start balance with target "
3128                        "data profile %llu\n",
3129                        (unsigned long long)bctl->data.target);
3130                 ret = -EINVAL;
3131                 goto out;
3132         }
3133         if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3134             (!alloc_profile_is_valid(bctl->meta.target, 1) ||
3135              (bctl->meta.target & ~allowed))) {
3136                 printk(KERN_ERR "btrfs: unable to start balance with target "
3137                        "metadata profile %llu\n",
3138                        (unsigned long long)bctl->meta.target);
3139                 ret = -EINVAL;
3140                 goto out;
3141         }
3142         if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3143             (!alloc_profile_is_valid(bctl->sys.target, 1) ||
3144              (bctl->sys.target & ~allowed))) {
3145                 printk(KERN_ERR "btrfs: unable to start balance with target "
3146                        "system profile %llu\n",
3147                        (unsigned long long)bctl->sys.target);
3148                 ret = -EINVAL;
3149                 goto out;
3150         }
3151
3152         /* allow dup'ed data chunks only in mixed mode */
3153         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3154             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3155                 printk(KERN_ERR "btrfs: dup for data is not allowed\n");
3156                 ret = -EINVAL;
3157                 goto out;
3158         }
3159
3160         /* allow to reduce meta or sys integrity only if force set */
3161         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3162                         BTRFS_BLOCK_GROUP_RAID10 |
3163                         BTRFS_BLOCK_GROUP_RAID5 |
3164                         BTRFS_BLOCK_GROUP_RAID6;
3165         do {
3166                 seq = read_seqbegin(&fs_info->profiles_lock);
3167
3168                 if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3169                      (fs_info->avail_system_alloc_bits & allowed) &&
3170                      !(bctl->sys.target & allowed)) ||
3171                     ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3172                      (fs_info->avail_metadata_alloc_bits & allowed) &&
3173                      !(bctl->meta.target & allowed))) {
3174                         if (bctl->flags & BTRFS_BALANCE_FORCE) {
3175                                 printk(KERN_INFO "btrfs: force reducing metadata "
3176                                        "integrity\n");
3177                         } else {
3178                                 printk(KERN_ERR "btrfs: balance will reduce metadata "
3179                                        "integrity, use force if you want this\n");
3180                                 ret = -EINVAL;
3181                                 goto out;
3182                         }
3183                 }
3184         } while (read_seqretry(&fs_info->profiles_lock, seq));
3185
3186         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3187                 int num_tolerated_disk_barrier_failures;
3188                 u64 target = bctl->sys.target;
3189
3190                 num_tolerated_disk_barrier_failures =
3191                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3192                 if (num_tolerated_disk_barrier_failures > 0 &&
3193                     (target &
3194                      (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3195                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
3196                         num_tolerated_disk_barrier_failures = 0;
3197                 else if (num_tolerated_disk_barrier_failures > 1 &&
3198                          (target &
3199                           (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
3200                         num_tolerated_disk_barrier_failures = 1;
3201
3202                 fs_info->num_tolerated_disk_barrier_failures =
3203                         num_tolerated_disk_barrier_failures;
3204         }
3205
3206         ret = insert_balance_item(fs_info->tree_root, bctl);
3207         if (ret && ret != -EEXIST)
3208                 goto out;
3209
3210         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3211                 BUG_ON(ret == -EEXIST);
3212                 set_balance_control(bctl);
3213         } else {
3214                 BUG_ON(ret != -EEXIST);
3215                 spin_lock(&fs_info->balance_lock);
3216                 update_balance_args(bctl);
3217                 spin_unlock(&fs_info->balance_lock);
3218         }
3219
3220         atomic_inc(&fs_info->balance_running);
3221         mutex_unlock(&fs_info->balance_mutex);
3222
3223         ret = __btrfs_balance(fs_info);
3224
3225         mutex_lock(&fs_info->balance_mutex);
3226         atomic_dec(&fs_info->balance_running);
3227
3228         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3229                 fs_info->num_tolerated_disk_barrier_failures =
3230                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3231         }
3232
3233         if (bargs) {
3234                 memset(bargs, 0, sizeof(*bargs));
3235                 update_ioctl_balance_args(fs_info, 0, bargs);
3236         }
3237
3238         wake_up(&fs_info->balance_wait_q);
3239
3240         return ret;
3241 out:
3242         if (bctl->flags & BTRFS_BALANCE_RESUME)
3243                 __cancel_balance(fs_info);
3244         else {
3245                 kfree(bctl);
3246                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3247         }
3248         return ret;
3249 }
3250
3251 static int balance_kthread(void *data)
3252 {
3253         struct btrfs_fs_info *fs_info = data;
3254         int ret = 0;
3255
3256         mutex_lock(&fs_info->volume_mutex);
3257         mutex_lock(&fs_info->balance_mutex);
3258
3259         if (fs_info->balance_ctl) {
3260                 printk(KERN_INFO "btrfs: continuing balance\n");
3261                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3262         }
3263
3264         mutex_unlock(&fs_info->balance_mutex);
3265         mutex_unlock(&fs_info->volume_mutex);
3266
3267         return ret;
3268 }
3269
3270 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3271 {
3272         struct task_struct *tsk;
3273
3274         spin_lock(&fs_info->balance_lock);
3275         if (!fs_info->balance_ctl) {
3276                 spin_unlock(&fs_info->balance_lock);
3277                 return 0;
3278         }
3279         spin_unlock(&fs_info->balance_lock);
3280
3281         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3282                 printk(KERN_INFO "btrfs: force skipping balance\n");
3283                 return 0;
3284         }
3285
3286         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3287         if (IS_ERR(tsk))
3288                 return PTR_ERR(tsk);
3289
3290         return 0;
3291 }
3292
3293 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3294 {
3295         struct btrfs_balance_control *bctl;
3296         struct btrfs_balance_item *item;
3297         struct btrfs_disk_balance_args disk_bargs;
3298         struct btrfs_path *path;
3299         struct extent_buffer *leaf;
3300         struct btrfs_key key;
3301         int ret;
3302
3303         path = btrfs_alloc_path();
3304         if (!path)
3305                 return -ENOMEM;
3306
3307         key.objectid = BTRFS_BALANCE_OBJECTID;
3308         key.type = BTRFS_BALANCE_ITEM_KEY;
3309         key.offset = 0;
3310
3311         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3312         if (ret < 0)
3313                 goto out;
3314         if (ret > 0) { /* ret = -ENOENT; */
3315                 ret = 0;
3316                 goto out;
3317         }
3318
3319         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3320         if (!bctl) {
3321                 ret = -ENOMEM;
3322                 goto out;
3323         }
3324
3325         leaf = path->nodes[0];
3326         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3327
3328         bctl->fs_info = fs_info;
3329         bctl->flags = btrfs_balance_flags(leaf, item);
3330         bctl->flags |= BTRFS_BALANCE_RESUME;
3331
3332         btrfs_balance_data(leaf, item, &disk_bargs);
3333         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3334         btrfs_balance_meta(leaf, item, &disk_bargs);
3335         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3336         btrfs_balance_sys(leaf, item, &disk_bargs);
3337         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3338
3339         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3340
3341         mutex_lock(&fs_info->volume_mutex);
3342         mutex_lock(&fs_info->balance_mutex);
3343
3344         set_balance_control(bctl);
3345
3346         mutex_unlock(&fs_info->balance_mutex);
3347         mutex_unlock(&fs_info->volume_mutex);
3348 out:
3349         btrfs_free_path(path);
3350         return ret;
3351 }
3352
3353 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3354 {
3355         int ret = 0;
3356
3357         mutex_lock(&fs_info->balance_mutex);
3358         if (!fs_info->balance_ctl) {
3359                 mutex_unlock(&fs_info->balance_mutex);
3360                 return -ENOTCONN;
3361         }
3362
3363         if (atomic_read(&fs_info->balance_running)) {
3364                 atomic_inc(&fs_info->balance_pause_req);
3365                 mutex_unlock(&fs_info->balance_mutex);
3366
3367                 wait_event(fs_info->balance_wait_q,
3368                            atomic_read(&fs_info->balance_running) == 0);
3369
3370                 mutex_lock(&fs_info->balance_mutex);
3371                 /* we are good with balance_ctl ripped off from under us */
3372                 BUG_ON(atomic_read(&fs_info->balance_running));
3373                 atomic_dec(&fs_info->balance_pause_req);
3374         } else {
3375                 ret = -ENOTCONN;
3376         }
3377
3378         mutex_unlock(&fs_info->balance_mutex);
3379         return ret;
3380 }
3381
3382 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3383 {
3384         mutex_lock(&fs_info->balance_mutex);
3385         if (!fs_info->balance_ctl) {
3386                 mutex_unlock(&fs_info->balance_mutex);
3387                 return -ENOTCONN;
3388         }
3389
3390         atomic_inc(&fs_info->balance_cancel_req);
3391         /*
3392          * if we are running just wait and return, balance item is
3393          * deleted in btrfs_balance in this case
3394          */
3395         if (atomic_read(&fs_info->balance_running)) {
3396                 mutex_unlock(&fs_info->balance_mutex);
3397                 wait_event(fs_info->balance_wait_q,
3398                            atomic_read(&fs_info->balance_running) == 0);
3399                 mutex_lock(&fs_info->balance_mutex);
3400         } else {
3401                 /* __cancel_balance needs volume_mutex */
3402                 mutex_unlock(&fs_info->balance_mutex);
3403                 mutex_lock(&fs_info->volume_mutex);
3404                 mutex_lock(&fs_info->balance_mutex);
3405
3406                 if (fs_info->balance_ctl)
3407                         __cancel_balance(fs_info);
3408
3409                 mutex_unlock(&fs_info->volume_mutex);
3410         }
3411
3412         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3413         atomic_dec(&fs_info->balance_cancel_req);
3414         mutex_unlock(&fs_info->balance_mutex);
3415         return 0;
3416 }
3417
3418 /*
3419  * shrinking a device means finding all of the device extents past
3420  * the new size, and then following the back refs to the chunks.
3421  * The chunk relocation code actually frees the device extent
3422  */
3423 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3424 {
3425         struct btrfs_trans_handle *trans;
3426         struct btrfs_root *root = device->dev_root;
3427         struct btrfs_dev_extent *dev_extent = NULL;
3428         struct btrfs_path *path;
3429         u64 length;
3430         u64 chunk_tree;
3431         u64 chunk_objectid;
3432         u64 chunk_offset;
3433         int ret;
3434         int slot;
3435         int failed = 0;
3436         bool retried = false;
3437         struct extent_buffer *l;
3438         struct btrfs_key key;
3439         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3440         u64 old_total = btrfs_super_total_bytes(super_copy);
3441         u64 old_size = device->total_bytes;
3442         u64 diff = device->total_bytes - new_size;
3443
3444         if (device->is_tgtdev_for_dev_replace)
3445                 return -EINVAL;
3446
3447         path = btrfs_alloc_path();
3448         if (!path)
3449                 return -ENOMEM;
3450
3451         path->reada = 2;
3452
3453         lock_chunks(root);
3454
3455         device->total_bytes = new_size;
3456         if (device->writeable) {
3457                 device->fs_devices->total_rw_bytes -= diff;
3458                 spin_lock(&root->fs_info->free_chunk_lock);
3459                 root->fs_info->free_chunk_space -= diff;
3460                 spin_unlock(&root->fs_info->free_chunk_lock);
3461         }
3462         unlock_chunks(root);
3463
3464 again:
3465         key.objectid = device->devid;
3466         key.offset = (u64)-1;
3467         key.type = BTRFS_DEV_EXTENT_KEY;
3468
3469         do {
3470                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3471                 if (ret < 0)
3472                         goto done;
3473
3474                 ret = btrfs_previous_item(root, path, 0, key.type);
3475                 if (ret < 0)
3476                         goto done;
3477                 if (ret) {
3478                         ret = 0;
3479                         btrfs_release_path(path);
3480                         break;
3481                 }
3482
3483                 l = path->nodes[0];
3484                 slot = path->slots[0];
3485                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
3486
3487                 if (key.objectid != device->devid) {
3488                         btrfs_release_path(path);
3489                         break;
3490                 }
3491
3492                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3493                 length = btrfs_dev_extent_length(l, dev_extent);
3494
3495                 if (key.offset + length <= new_size) {
3496                         btrfs_release_path(path);
3497                         break;
3498                 }
3499
3500                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
3501                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
3502                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3503                 btrfs_release_path(path);
3504
3505                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
3506                                            chunk_offset);
3507                 if (ret && ret != -ENOSPC)
3508                         goto done;
3509                 if (ret == -ENOSPC)
3510                         failed++;
3511         } while (key.offset-- > 0);
3512
3513         if (failed && !retried) {
3514                 failed = 0;
3515                 retried = true;
3516                 goto again;
3517         } else if (failed && retried) {
3518                 ret = -ENOSPC;
3519                 lock_chunks(root);
3520
3521                 device->total_bytes = old_size;
3522                 if (device->writeable)
3523                         device->fs_devices->total_rw_bytes += diff;
3524                 spin_lock(&root->fs_info->free_chunk_lock);
3525                 root->fs_info->free_chunk_space += diff;
3526                 spin_unlock(&root->fs_info->free_chunk_lock);
3527                 unlock_chunks(root);
3528                 goto done;
3529         }
3530
3531         /* Shrinking succeeded, else we would be at "done". */
3532         trans = btrfs_start_transaction(root, 0);
3533         if (IS_ERR(trans)) {
3534                 ret = PTR_ERR(trans);
3535                 goto done;
3536         }
3537
3538         lock_chunks(root);
3539
3540         device->disk_total_bytes = new_size;
3541         /* Now btrfs_update_device() will change the on-disk size. */
3542         ret = btrfs_update_device(trans, device);
3543         if (ret) {
3544                 unlock_chunks(root);
3545                 btrfs_end_transaction(trans, root);
3546                 goto done;
3547         }
3548         WARN_ON(diff > old_total);
3549         btrfs_set_super_total_bytes(super_copy, old_total - diff);
3550         unlock_chunks(root);
3551         btrfs_end_transaction(trans, root);
3552 done:
3553         btrfs_free_path(path);
3554         return ret;
3555 }
3556
3557 static int btrfs_add_system_chunk(struct btrfs_root *root,
3558                            struct btrfs_key *key,
3559                            struct btrfs_chunk *chunk, int item_size)
3560 {
3561         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3562         struct btrfs_disk_key disk_key;
3563         u32 array_size;
3564         u8 *ptr;
3565
3566         array_size = btrfs_super_sys_array_size(super_copy);
3567         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
3568                 return -EFBIG;
3569
3570         ptr = super_copy->sys_chunk_array + array_size;
3571         btrfs_cpu_key_to_disk(&disk_key, key);
3572         memcpy(ptr, &disk_key, sizeof(disk_key));
3573         ptr += sizeof(disk_key);
3574         memcpy(ptr, chunk, item_size);
3575         item_size += sizeof(disk_key);
3576         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
3577         return 0;
3578 }
3579
3580 /*
3581  * sort the devices in descending order by max_avail, total_avail
3582  */
3583 static int btrfs_cmp_device_info(const void *a, const void *b)
3584 {
3585         const struct btrfs_device_info *di_a = a;
3586         const struct btrfs_device_info *di_b = b;
3587
3588         if (di_a->max_avail > di_b->max_avail)
3589                 return -1;
3590         if (di_a->max_avail < di_b->max_avail)
3591                 return 1;
3592         if (di_a->total_avail > di_b->total_avail)
3593                 return -1;
3594         if (di_a->total_avail < di_b->total_avail)
3595                 return 1;
3596         return 0;
3597 }
3598
3599 struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
3600         [BTRFS_RAID_RAID10] = {
3601                 .sub_stripes    = 2,
3602                 .dev_stripes    = 1,
3603                 .devs_max       = 0,    /* 0 == as many as possible */
3604                 .devs_min       = 4,
3605                 .devs_increment = 2,
3606                 .ncopies        = 2,
3607         },
3608         [BTRFS_RAID_RAID1] = {
3609                 .sub_stripes    = 1,
3610                 .dev_stripes    = 1,
3611                 .devs_max       = 2,
3612                 .devs_min       = 2,
3613                 .devs_increment = 2,
3614                 .ncopies        = 2,
3615         },
3616         [BTRFS_RAID_DUP] = {
3617                 .sub_stripes    = 1,
3618                 .dev_stripes    = 2,
3619                 .devs_max       = 1,
3620                 .devs_min       = 1,
3621                 .devs_increment = 1,
3622                 .ncopies        = 2,
3623         },
3624         [BTRFS_RAID_RAID0] = {
3625                 .sub_stripes    = 1,
3626                 .dev_stripes    = 1,
3627                 .devs_max       = 0,
3628                 .devs_min       = 2,
3629                 .devs_increment = 1,
3630                 .ncopies        = 1,
3631         },
3632         [BTRFS_RAID_SINGLE] = {
3633                 .sub_stripes    = 1,
3634                 .dev_stripes    = 1,
3635                 .devs_max       = 1,
3636                 .devs_min       = 1,
3637                 .devs_increment = 1,
3638                 .ncopies        = 1,
3639         },
3640         [BTRFS_RAID_RAID5] = {
3641                 .sub_stripes    = 1,
3642                 .dev_stripes    = 1,
3643                 .devs_max       = 0,
3644                 .devs_min       = 2,
3645                 .devs_increment = 1,
3646                 .ncopies        = 2,
3647         },
3648         [BTRFS_RAID_RAID6] = {
3649                 .sub_stripes    = 1,
3650                 .dev_stripes    = 1,
3651                 .devs_max       = 0,
3652                 .devs_min       = 3,
3653                 .devs_increment = 1,
3654                 .ncopies        = 3,
3655         },
3656 };
3657
3658 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
3659 {
3660         /* TODO allow them to set a preferred stripe size */
3661         return 64 * 1024;
3662 }
3663
3664 static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
3665 {
3666         u64 features;
3667
3668         if (!(type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)))
3669                 return;
3670
3671         features = btrfs_super_incompat_flags(info->super_copy);
3672         if (features & BTRFS_FEATURE_INCOMPAT_RAID56)
3673                 return;
3674
3675         features |= BTRFS_FEATURE_INCOMPAT_RAID56;
3676         btrfs_set_super_incompat_flags(info->super_copy, features);
3677         printk(KERN_INFO "btrfs: setting RAID5/6 feature flag\n");
3678 }
3679
3680 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3681                                struct btrfs_root *extent_root,
3682                                struct map_lookup **map_ret,
3683                                u64 *num_bytes_out, u64 *stripe_size_out,
3684                                u64 start, u64 type)
3685 {
3686         struct btrfs_fs_info *info = extent_root->fs_info;
3687         struct btrfs_fs_devices *fs_devices = info->fs_devices;
3688         struct list_head *cur;
3689         struct map_lookup *map = NULL;
3690         struct extent_map_tree *em_tree;
3691         struct extent_map *em;
3692         struct btrfs_device_info *devices_info = NULL;
3693         u64 total_avail;
3694         int num_stripes;        /* total number of stripes to allocate */
3695         int data_stripes;       /* number of stripes that count for
3696                                    block group size */
3697         int sub_stripes;        /* sub_stripes info for map */
3698         int dev_stripes;        /* stripes per dev */
3699         int devs_max;           /* max devs to use */
3700         int devs_min;           /* min devs needed */
3701         int devs_increment;     /* ndevs has to be a multiple of this */
3702         int ncopies;            /* how many copies to data has */
3703         int ret;
3704         u64 max_stripe_size;
3705         u64 max_chunk_size;
3706         u64 stripe_size;
3707         u64 num_bytes;
3708         u64 raid_stripe_len = BTRFS_STRIPE_LEN;
3709         int ndevs;
3710         int i;
3711         int j;
3712         int index;
3713
3714         BUG_ON(!alloc_profile_is_valid(type, 0));
3715
3716         if (list_empty(&fs_devices->alloc_list))
3717                 return -ENOSPC;
3718
3719         index = __get_raid_index(type);
3720
3721         sub_stripes = btrfs_raid_array[index].sub_stripes;
3722         dev_stripes = btrfs_raid_array[index].dev_stripes;
3723         devs_max = btrfs_raid_array[index].devs_max;
3724         devs_min = btrfs_raid_array[index].devs_min;
3725         devs_increment = btrfs_raid_array[index].devs_increment;
3726         ncopies = btrfs_raid_array[index].ncopies;
3727
3728         if (type & BTRFS_BLOCK_GROUP_DATA) {
3729                 max_stripe_size = 1024 * 1024 * 1024;
3730                 max_chunk_size = 10 * max_stripe_size;
3731         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
3732                 /* for larger filesystems, use larger metadata chunks */
3733                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
3734                         max_stripe_size = 1024 * 1024 * 1024;
3735                 else
3736                         max_stripe_size = 256 * 1024 * 1024;
3737                 max_chunk_size = max_stripe_size;
3738         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
3739                 max_stripe_size = 32 * 1024 * 1024;
3740                 max_chunk_size = 2 * max_stripe_size;
3741         } else {
3742                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
3743                        type);
3744                 BUG_ON(1);
3745         }
3746
3747         /* we don't want a chunk larger than 10% of writeable space */
3748         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
3749                              max_chunk_size);
3750
3751         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
3752                                GFP_NOFS);
3753         if (!devices_info)
3754                 return -ENOMEM;
3755
3756         cur = fs_devices->alloc_list.next;
3757
3758         /*
3759          * in the first pass through the devices list, we gather information
3760          * about the available holes on each device.
3761          */
3762         ndevs = 0;
3763         while (cur != &fs_devices->alloc_list) {
3764                 struct btrfs_device *device;
3765                 u64 max_avail;
3766                 u64 dev_offset;
3767
3768                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
3769
3770                 cur = cur->next;
3771
3772                 if (!device->writeable) {
3773                         WARN(1, KERN_ERR
3774                                "btrfs: read-only device in alloc_list\n");
3775                         continue;
3776                 }
3777
3778                 if (!device->in_fs_metadata ||
3779                     device->is_tgtdev_for_dev_replace)
3780                         continue;
3781
3782                 if (device->total_bytes > device->bytes_used)
3783                         total_avail = device->total_bytes - device->bytes_used;
3784                 else
3785                         total_avail = 0;
3786
3787                 /* If there is no space on this device, skip it. */
3788                 if (total_avail == 0)
3789                         continue;
3790
3791                 ret = find_free_dev_extent(device,
3792                                            max_stripe_size * dev_stripes,
3793                                            &dev_offset, &max_avail);
3794                 if (ret && ret != -ENOSPC)
3795                         goto error;
3796
3797                 if (ret == 0)
3798                         max_avail = max_stripe_size * dev_stripes;
3799
3800                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
3801                         continue;
3802
3803                 if (ndevs == fs_devices->rw_devices) {
3804                         WARN(1, "%s: found more than %llu devices\n",
3805                              __func__, fs_devices->rw_devices);
3806                         break;
3807                 }
3808                 devices_info[ndevs].dev_offset = dev_offset;
3809                 devices_info[ndevs].max_avail = max_avail;
3810                 devices_info[ndevs].total_avail = total_avail;
3811                 devices_info[ndevs].dev = device;
3812                 ++ndevs;
3813         }
3814
3815         /*
3816          * now sort the devices by hole size / available space
3817          */
3818         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
3819              btrfs_cmp_device_info, NULL);
3820
3821         /* round down to number of usable stripes */
3822         ndevs -= ndevs % devs_increment;
3823
3824         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
3825                 ret = -ENOSPC;
3826                 goto error;
3827         }
3828
3829         if (devs_max && ndevs > devs_max)
3830                 ndevs = devs_max;
3831         /*
3832          * the primary goal is to maximize the number of stripes, so use as many
3833          * devices as possible, even if the stripes are not maximum sized.
3834          */
3835         stripe_size = devices_info[ndevs-1].max_avail;
3836         num_stripes = ndevs * dev_stripes;
3837
3838         /*
3839          * this will have to be fixed for RAID1 and RAID10 over
3840          * more drives
3841          */
3842         data_stripes = num_stripes / ncopies;
3843
3844         if (type & BTRFS_BLOCK_GROUP_RAID5) {
3845                 raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
3846                                  btrfs_super_stripesize(info->super_copy));
3847                 data_stripes = num_stripes - 1;
3848         }
3849         if (type & BTRFS_BLOCK_GROUP_RAID6) {
3850                 raid_stripe_len = find_raid56_stripe_len(ndevs - 2,
3851                                  btrfs_super_stripesize(info->super_copy));
3852                 data_stripes = num_stripes - 2;
3853         }
3854
3855         /*
3856          * Use the number of data stripes to figure out how big this chunk
3857          * is really going to be in terms of logical address space,
3858          * and compare that answer with the max chunk size
3859          */
3860         if (stripe_size * data_stripes > max_chunk_size) {
3861                 u64 mask = (1ULL << 24) - 1;
3862                 stripe_size = max_chunk_size;
3863                 do_div(stripe_size, data_stripes);
3864
3865                 /* bump the answer up to a 16MB boundary */
3866                 stripe_size = (stripe_size + mask) & ~mask;
3867
3868                 /* but don't go higher than the limits we found
3869                  * while searching for free extents
3870                  */
3871                 if (stripe_size > devices_info[ndevs-1].max_avail)
3872                         stripe_size = devices_info[ndevs-1].max_avail;
3873         }
3874
3875         do_div(stripe_size, dev_stripes);
3876
3877         /* align to BTRFS_STRIPE_LEN */
3878         do_div(stripe_size, raid_stripe_len);
3879         stripe_size *= raid_stripe_len;
3880
3881         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3882         if (!map) {
3883                 ret = -ENOMEM;
3884                 goto error;
3885         }
3886         map->num_stripes = num_stripes;
3887
3888         for (i = 0; i < ndevs; ++i) {
3889                 for (j = 0; j < dev_stripes; ++j) {
3890                         int s = i * dev_stripes + j;
3891                         map->stripes[s].dev = devices_info[i].dev;
3892                         map->stripes[s].physical = devices_info[i].dev_offset +
3893                                                    j * stripe_size;
3894                 }
3895         }
3896         map->sector_size = extent_root->sectorsize;
3897         map->stripe_len = raid_stripe_len;
3898         map->io_align = raid_stripe_len;
3899         map->io_width = raid_stripe_len;
3900         map->type = type;
3901         map->sub_stripes = sub_stripes;
3902
3903         *map_ret = map;
3904         num_bytes = stripe_size * data_stripes;
3905
3906         *stripe_size_out = stripe_size;
3907         *num_bytes_out = num_bytes;
3908
3909         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
3910
3911         em = alloc_extent_map();
3912         if (!em) {
3913                 ret = -ENOMEM;
3914                 goto error;
3915         }
3916         em->bdev = (struct block_device *)map;
3917         em->start = start;
3918         em->len = num_bytes;
3919         em->block_start = 0;
3920         em->block_len = em->len;
3921
3922         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
3923         write_lock(&em_tree->lock);
3924         ret = add_extent_mapping(em_tree, em);
3925         write_unlock(&em_tree->lock);
3926         if (ret) {
3927                 free_extent_map(em);
3928                 goto error;
3929         }
3930
3931         for (i = 0; i < map->num_stripes; ++i) {
3932                 struct btrfs_device *device;
3933                 u64 dev_offset;
3934
3935                 device = map->stripes[i].dev;
3936                 dev_offset = map->stripes[i].physical;
3937
3938                 ret = btrfs_alloc_dev_extent(trans, device,
3939                                 info->chunk_root->root_key.objectid,
3940                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3941                                 start, dev_offset, stripe_size);
3942                 if (ret)
3943                         goto error_dev_extent;
3944         }
3945
3946         ret = btrfs_make_block_group(trans, extent_root, 0, type,
3947                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3948                                      start, num_bytes);
3949         if (ret) {
3950                 i = map->num_stripes - 1;
3951                 goto error_dev_extent;
3952         }
3953
3954         free_extent_map(em);
3955         check_raid56_incompat_flag(extent_root->fs_info, type);
3956
3957         kfree(devices_info);
3958         return 0;
3959
3960 error_dev_extent:
3961         for (; i >= 0; i--) {
3962                 struct btrfs_device *device;
3963                 int err;
3964
3965                 device = map->stripes[i].dev;
3966                 err = btrfs_free_dev_extent(trans, device, start);
3967                 if (err) {
3968                         btrfs_abort_transaction(trans, extent_root, err);
3969                         break;
3970                 }
3971         }
3972         write_lock(&em_tree->lock);
3973         remove_extent_mapping(em_tree, em);
3974         write_unlock(&em_tree->lock);
3975
3976         /* One for our allocation */
3977         free_extent_map(em);
3978         /* One for the tree reference */
3979         free_extent_map(em);
3980 error:
3981         kfree(map);
3982         kfree(devices_info);
3983         return ret;
3984 }
3985
3986 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
3987                                 struct btrfs_root *extent_root,
3988                                 struct map_lookup *map, u64 chunk_offset,
3989                                 u64 chunk_size, u64 stripe_size)
3990 {
3991         u64 dev_offset;
3992         struct btrfs_key key;
3993         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3994         struct btrfs_device *device;
3995         struct btrfs_chunk *chunk;
3996         struct btrfs_stripe *stripe;
3997         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
3998         int index = 0;
3999         int ret;
4000
4001         chunk = kzalloc(item_size, GFP_NOFS);
4002         if (!chunk)
4003                 return -ENOMEM;
4004
4005         index = 0;
4006         while (index < map->num_stripes) {
4007                 device = map->stripes[index].dev;
4008                 device->bytes_used += stripe_size;
4009                 ret = btrfs_update_device(trans, device);
4010                 if (ret)
4011                         goto out_free;
4012                 index++;
4013         }
4014
4015         spin_lock(&extent_root->fs_info->free_chunk_lock);
4016         extent_root->fs_info->free_chunk_space -= (stripe_size *
4017                                                    map->num_stripes);
4018         spin_unlock(&extent_root->fs_info->free_chunk_lock);
4019
4020         index = 0;
4021         stripe = &chunk->stripe;
4022         while (index < map->num_stripes) {
4023                 device = map->stripes[index].dev;
4024                 dev_offset = map->stripes[index].physical;
4025
4026                 btrfs_set_stack_stripe_devid(stripe, device->devid);
4027                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
4028                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
4029                 stripe++;
4030                 index++;
4031         }
4032
4033         btrfs_set_stack_chunk_length(chunk, chunk_size);
4034         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
4035         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
4036         btrfs_set_stack_chunk_type(chunk, map->type);
4037         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
4038         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
4039         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
4040         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
4041         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
4042
4043         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
4044         key.type = BTRFS_CHUNK_ITEM_KEY;
4045         key.offset = chunk_offset;
4046
4047         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
4048
4049         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
4050                 /*
4051                  * TODO: Cleanup of inserted chunk root in case of
4052                  * failure.
4053                  */
4054                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
4055                                              item_size);
4056         }
4057
4058 out_free:
4059         kfree(chunk);
4060         return ret;
4061 }
4062
4063 /*
4064  * Chunk allocation falls into two parts. The first part does works
4065  * that make the new allocated chunk useable, but not do any operation
4066  * that modifies the chunk tree. The second part does the works that
4067  * require modifying the chunk tree. This division is important for the
4068  * bootstrap process of adding storage to a seed btrfs.
4069  */
4070 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4071                       struct btrfs_root *extent_root, u64 type)
4072 {
4073         u64 chunk_offset;
4074         u64 chunk_size;
4075         u64 stripe_size;
4076         struct map_lookup *map;
4077         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
4078         int ret;
4079
4080         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4081                               &chunk_offset);
4082         if (ret)
4083                 return ret;
4084
4085         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
4086                                   &stripe_size, chunk_offset, type);
4087         if (ret)
4088                 return ret;
4089
4090         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
4091                                    chunk_size, stripe_size);
4092         if (ret)
4093                 return ret;
4094         return 0;
4095 }
4096
4097 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
4098                                          struct btrfs_root *root,
4099                                          struct btrfs_device *device)
4100 {
4101         u64 chunk_offset;
4102         u64 sys_chunk_offset;
4103         u64 chunk_size;
4104         u64 sys_chunk_size;
4105         u64 stripe_size;
4106         u64 sys_stripe_size;
4107         u64 alloc_profile;
4108         struct map_lookup *map;
4109         struct map_lookup *sys_map;
4110         struct btrfs_fs_info *fs_info = root->fs_info;
4111         struct btrfs_root *extent_root = fs_info->extent_root;
4112         int ret;
4113
4114         ret = find_next_chunk(fs_info->chunk_root,
4115                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
4116         if (ret)
4117                 return ret;
4118
4119         alloc_profile = btrfs_get_alloc_profile(extent_root, 0);
4120         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
4121                                   &stripe_size, chunk_offset, alloc_profile);
4122         if (ret)
4123                 return ret;
4124
4125         sys_chunk_offset = chunk_offset + chunk_size;
4126
4127         alloc_profile = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
4128         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
4129                                   &sys_chunk_size, &sys_stripe_size,
4130                                   sys_chunk_offset, alloc_profile);
4131         if (ret) {
4132                 btrfs_abort_transaction(trans, root, ret);
4133                 goto out;
4134         }
4135
4136         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
4137         if (ret) {
4138                 btrfs_abort_transaction(trans, root, ret);
4139                 goto out;
4140         }
4141
4142         /*
4143          * Modifying chunk tree needs allocating new blocks from both
4144          * system block group and metadata block group. So we only can
4145          * do operations require modifying the chunk tree after both
4146          * block groups were created.
4147          */
4148         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
4149                                    chunk_size, stripe_size);
4150         if (ret) {
4151                 btrfs_abort_transaction(trans, root, ret);
4152                 goto out;
4153         }
4154
4155         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
4156                                    sys_chunk_offset, sys_chunk_size,
4157                                    sys_stripe_size);
4158         if (ret)
4159                 btrfs_abort_transaction(trans, root, ret);
4160
4161 out:
4162
4163         return ret;
4164 }
4165
4166 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
4167 {
4168         struct extent_map *em;
4169         struct map_lookup *map;
4170         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4171         int readonly = 0;
4172         int i;
4173
4174         read_lock(&map_tree->map_tree.lock);
4175         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
4176         read_unlock(&map_tree->map_tree.lock);
4177         if (!em)
4178                 return 1;
4179
4180         if (btrfs_test_opt(root, DEGRADED)) {
4181                 free_extent_map(em);
4182                 return 0;
4183         }
4184
4185         map = (struct map_lookup *)em->bdev;
4186         for (i = 0; i < map->num_stripes; i++) {
4187                 if (!map->stripes[i].dev->writeable) {
4188                         readonly = 1;
4189                         break;
4190                 }
4191         }
4192         free_extent_map(em);
4193         return readonly;
4194 }
4195
4196 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
4197 {
4198         extent_map_tree_init(&tree->map_tree);
4199 }
4200
4201 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
4202 {
4203         struct extent_map *em;
4204
4205         while (1) {
4206                 write_lock(&tree->map_tree.lock);
4207                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
4208                 if (em)
4209                         remove_extent_mapping(&tree->map_tree, em);
4210                 write_unlock(&tree->map_tree.lock);
4211                 if (!em)
4212                         break;
4213                 kfree(em->bdev);
4214                 /* once for us */
4215                 free_extent_map(em);
4216                 /* once for the tree */
4217                 free_extent_map(em);
4218         }
4219 }
4220
4221 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
4222 {
4223         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4224         struct extent_map *em;
4225         struct map_lookup *map;
4226         struct extent_map_tree *em_tree = &map_tree->map_tree;
4227         int ret;
4228
4229         read_lock(&em_tree->lock);
4230         em = lookup_extent_mapping(em_tree, logical, len);
4231         read_unlock(&em_tree->lock);
4232         BUG_ON(!em);
4233
4234         BUG_ON(em->start > logical || em->start + em->len < logical);
4235         map = (struct map_lookup *)em->bdev;
4236         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
4237                 ret = map->num_stripes;
4238         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4239                 ret = map->sub_stripes;
4240         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
4241                 ret = 2;
4242         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
4243                 ret = 3;
4244         else
4245                 ret = 1;
4246         free_extent_map(em);
4247
4248         btrfs_dev_replace_lock(&fs_info->dev_replace);
4249         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
4250                 ret++;
4251         btrfs_dev_replace_unlock(&fs_info->dev_replace);
4252
4253         return ret;
4254 }
4255
4256 unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
4257                                     struct btrfs_mapping_tree *map_tree,
4258                                     u64 logical)
4259 {
4260         struct extent_map *em;
4261         struct map_lookup *map;
4262         struct extent_map_tree *em_tree = &map_tree->map_tree;
4263         unsigned long len = root->sectorsize;
4264
4265         read_lock(&em_tree->lock);
4266         em = lookup_extent_mapping(em_tree, logical, len);
4267         read_unlock(&em_tree->lock);
4268         BUG_ON(!em);
4269
4270         BUG_ON(em->start > logical || em->start + em->len < logical);
4271         map = (struct map_lookup *)em->bdev;
4272         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4273                          BTRFS_BLOCK_GROUP_RAID6)) {
4274                 len = map->stripe_len * nr_data_stripes(map);
4275         }
4276         free_extent_map(em);
4277         return len;
4278 }
4279
4280 int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
4281                            u64 logical, u64 len, int mirror_num)
4282 {
4283         struct extent_map *em;
4284         struct map_lookup *map;
4285         struct extent_map_tree *em_tree = &map_tree->map_tree;
4286         int ret = 0;
4287
4288         read_lock(&em_tree->lock);
4289         em = lookup_extent_mapping(em_tree, logical, len);
4290         read_unlock(&em_tree->lock);
4291         BUG_ON(!em);
4292
4293         BUG_ON(em->start > logical || em->start + em->len < logical);
4294         map = (struct map_lookup *)em->bdev;
4295         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4296                          BTRFS_BLOCK_GROUP_RAID6))
4297                 ret = 1;
4298         free_extent_map(em);
4299         return ret;
4300 }
4301
4302 static int find_live_mirror(struct btrfs_fs_info *fs_info,
4303                             struct map_lookup *map, int first, int num,
4304                             int optimal, int dev_replace_is_ongoing)
4305 {
4306         int i;
4307         int tolerance;
4308         struct btrfs_device *srcdev;
4309
4310         if (dev_replace_is_ongoing &&
4311             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
4312              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
4313                 srcdev = fs_info->dev_replace.srcdev;
4314         else
4315                 srcdev = NULL;
4316
4317         /*
4318          * try to avoid the drive that is the source drive for a
4319          * dev-replace procedure, only choose it if no other non-missing
4320          * mirror is available
4321          */
4322         for (tolerance = 0; tolerance < 2; tolerance++) {
4323                 if (map->stripes[optimal].dev->bdev &&
4324                     (tolerance || map->stripes[optimal].dev != srcdev))
4325                         return optimal;
4326                 for (i = first; i < first + num; i++) {
4327                         if (map->stripes[i].dev->bdev &&
4328                             (tolerance || map->stripes[i].dev != srcdev))
4329                                 return i;
4330                 }
4331         }
4332
4333         /* we couldn't find one that doesn't fail.  Just return something
4334          * and the io error handling code will clean up eventually
4335          */
4336         return optimal;
4337 }
4338
4339 static inline int parity_smaller(u64 a, u64 b)
4340 {
4341         return a > b;
4342 }
4343
4344 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
4345 static void sort_parity_stripes(struct btrfs_bio *bbio, u64 *raid_map)
4346 {
4347         struct btrfs_bio_stripe s;
4348         int i;
4349         u64 l;
4350         int again = 1;
4351
4352         while (again) {
4353                 again = 0;
4354                 for (i = 0; i < bbio->num_stripes - 1; i++) {
4355                         if (parity_smaller(raid_map[i], raid_map[i+1])) {
4356                                 s = bbio->stripes[i];
4357                                 l = raid_map[i];
4358                                 bbio->stripes[i] = bbio->stripes[i+1];
4359                                 raid_map[i] = raid_map[i+1];
4360                                 bbio->stripes[i+1] = s;
4361                                 raid_map[i+1] = l;
4362                                 again = 1;
4363                         }
4364                 }
4365         }
4366 }
4367
4368 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4369                              u64 logical, u64 *length,
4370                              struct btrfs_bio **bbio_ret,
4371                              int mirror_num, u64 **raid_map_ret)
4372 {
4373         struct extent_map *em;
4374         struct map_lookup *map;
4375         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4376         struct extent_map_tree *em_tree = &map_tree->map_tree;
4377         u64 offset;
4378         u64 stripe_offset;
4379         u64 stripe_end_offset;
4380         u64 stripe_nr;
4381         u64 stripe_nr_orig;
4382         u64 stripe_nr_end;
4383         u64 stripe_len;
4384         u64 *raid_map = NULL;
4385         int stripe_index;
4386         int i;
4387         int ret = 0;
4388         int num_stripes;
4389         int max_errors = 0;
4390         struct btrfs_bio *bbio = NULL;
4391         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
4392         int dev_replace_is_ongoing = 0;
4393         int num_alloc_stripes;
4394         int patch_the_first_stripe_for_dev_replace = 0;
4395         u64 physical_to_patch_in_first_stripe = 0;
4396         u64 raid56_full_stripe_start = (u64)-1;
4397
4398         read_lock(&em_tree->lock);
4399         em = lookup_extent_mapping(em_tree, logical, *length);
4400         read_unlock(&em_tree->lock);
4401
4402         if (!em) {
4403                 printk(KERN_CRIT "btrfs: unable to find logical %llu len %llu\n",
4404                        (unsigned long long)logical,
4405                        (unsigned long long)*length);
4406                 BUG();
4407         }
4408
4409         BUG_ON(em->start > logical || em->start + em->len < logical);
4410         map = (struct map_lookup *)em->bdev;
4411         offset = logical - em->start;
4412
4413         if (mirror_num > map->num_stripes)
4414                 mirror_num = 0;
4415
4416         stripe_len = map->stripe_len;
4417         stripe_nr = offset;
4418         /*
4419          * stripe_nr counts the total number of stripes we have to stride
4420          * to get to this block
4421          */
4422         do_div(stripe_nr, stripe_len);
4423
4424         stripe_offset = stripe_nr * stripe_len;
4425         BUG_ON(offset < stripe_offset);
4426
4427         /* stripe_offset is the offset of this block in its stripe*/
4428         stripe_offset = offset - stripe_offset;
4429
4430         /* if we're here for raid56, we need to know the stripe aligned start */
4431         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) {
4432                 unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
4433                 raid56_full_stripe_start = offset;
4434
4435                 /* allow a write of a full stripe, but make sure we don't
4436                  * allow straddling of stripes
4437                  */
4438                 do_div(raid56_full_stripe_start, full_stripe_len);
4439                 raid56_full_stripe_start *= full_stripe_len;
4440         }
4441
4442         if (rw & REQ_DISCARD) {
4443                 /* we don't discard raid56 yet */
4444                 if (map->type &
4445                     (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) {
4446                         ret = -EOPNOTSUPP;
4447                         goto out;
4448                 }
4449                 *length = min_t(u64, em->len - offset, *length);
4450         } else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
4451                 u64 max_len;
4452                 /* For writes to RAID[56], allow a full stripeset across all disks.
4453                    For other RAID types and for RAID[56] reads, just allow a single
4454                    stripe (on a single disk). */
4455                 if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6) &&
4456                     (rw & REQ_WRITE)) {
4457                         max_len = stripe_len * nr_data_stripes(map) -
4458                                 (offset - raid56_full_stripe_start);
4459                 } else {
4460                         /* we limit the length of each bio to what fits in a stripe */
4461                         max_len = stripe_len - stripe_offset;
4462                 }
4463                 *length = min_t(u64, em->len - offset, max_len);
4464         } else {
4465                 *length = em->len - offset;
4466         }
4467
4468         /* This is for when we're called from btrfs_merge_bio_hook() and all
4469            it cares about is the length */
4470         if (!bbio_ret)
4471                 goto out;
4472
4473         btrfs_dev_replace_lock(dev_replace);
4474         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
4475         if (!dev_replace_is_ongoing)
4476                 btrfs_dev_replace_unlock(dev_replace);
4477
4478         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
4479             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
4480             dev_replace->tgtdev != NULL) {
4481                 /*
4482                  * in dev-replace case, for repair case (that's the only
4483                  * case where the mirror is selected explicitly when
4484                  * calling btrfs_map_block), blocks left of the left cursor
4485                  * can also be read from the target drive.
4486                  * For REQ_GET_READ_MIRRORS, the target drive is added as
4487                  * the last one to the array of stripes. For READ, it also
4488                  * needs to be supported using the same mirror number.
4489                  * If the requested block is not left of the left cursor,
4490                  * EIO is returned. This can happen because btrfs_num_copies()
4491                  * returns one more in the dev-replace case.
4492                  */
4493                 u64 tmp_length = *length;
4494                 struct btrfs_bio *tmp_bbio = NULL;
4495                 int tmp_num_stripes;
4496                 u64 srcdev_devid = dev_replace->srcdev->devid;
4497                 int index_srcdev = 0;
4498                 int found = 0;
4499                 u64 physical_of_found = 0;
4500
4501                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
4502                              logical, &tmp_length, &tmp_bbio, 0, NULL);
4503                 if (ret) {
4504                         WARN_ON(tmp_bbio != NULL);
4505                         goto out;
4506                 }
4507
4508                 tmp_num_stripes = tmp_bbio->num_stripes;
4509                 if (mirror_num > tmp_num_stripes) {
4510                         /*
4511                          * REQ_GET_READ_MIRRORS does not contain this
4512                          * mirror, that means that the requested area
4513                          * is not left of the left cursor
4514                          */
4515                         ret = -EIO;
4516                         kfree(tmp_bbio);
4517                         goto out;
4518                 }
4519
4520                 /*
4521                  * process the rest of the function using the mirror_num
4522                  * of the source drive. Therefore look it up first.
4523                  * At the end, patch the device pointer to the one of the
4524                  * target drive.
4525                  */
4526                 for (i = 0; i < tmp_num_stripes; i++) {
4527                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
4528                                 /*
4529                                  * In case of DUP, in order to keep it
4530                                  * simple, only add the mirror with the
4531                                  * lowest physical address
4532                                  */
4533                                 if (found &&
4534                                     physical_of_found <=
4535                                      tmp_bbio->stripes[i].physical)
4536                                         continue;
4537                                 index_srcdev = i;
4538                                 found = 1;
4539                                 physical_of_found =
4540                                         tmp_bbio->stripes[i].physical;
4541                         }
4542                 }
4543
4544                 if (found) {
4545                         mirror_num = index_srcdev + 1;
4546                         patch_the_first_stripe_for_dev_replace = 1;
4547                         physical_to_patch_in_first_stripe = physical_of_found;
4548                 } else {
4549                         WARN_ON(1);
4550                         ret = -EIO;
4551                         kfree(tmp_bbio);
4552                         goto out;
4553                 }
4554
4555                 kfree(tmp_bbio);
4556         } else if (mirror_num > map->num_stripes) {
4557                 mirror_num = 0;
4558         }
4559
4560         num_stripes = 1;
4561         stripe_index = 0;
4562         stripe_nr_orig = stripe_nr;
4563         stripe_nr_end = ALIGN(offset + *length, map->stripe_len);
4564         do_div(stripe_nr_end, map->stripe_len);
4565         stripe_end_offset = stripe_nr_end * map->stripe_len -
4566                             (offset + *length);
4567
4568         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4569                 if (rw & REQ_DISCARD)
4570                         num_stripes = min_t(u64, map->num_stripes,
4571                                             stripe_nr_end - stripe_nr_orig);
4572                 stripe_index = do_div(stripe_nr, map->num_stripes);
4573         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
4574                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
4575                         num_stripes = map->num_stripes;
4576                 else if (mirror_num)
4577                         stripe_index = mirror_num - 1;
4578                 else {
4579                         stripe_index = find_live_mirror(fs_info, map, 0,
4580                                             map->num_stripes,
4581                                             current->pid % map->num_stripes,
4582                                             dev_replace_is_ongoing);
4583                         mirror_num = stripe_index + 1;
4584                 }
4585
4586         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
4587                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
4588                         num_stripes = map->num_stripes;
4589                 } else if (mirror_num) {
4590                         stripe_index = mirror_num - 1;
4591                 } else {
4592                         mirror_num = 1;
4593                 }
4594
4595         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4596                 int factor = map->num_stripes / map->sub_stripes;
4597
4598                 stripe_index = do_div(stripe_nr, factor);
4599                 stripe_index *= map->sub_stripes;
4600
4601                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
4602                         num_stripes = map->sub_stripes;
4603                 else if (rw & REQ_DISCARD)
4604                         num_stripes = min_t(u64, map->sub_stripes *
4605                                             (stripe_nr_end - stripe_nr_orig),
4606                                             map->num_stripes);
4607                 else if (mirror_num)
4608                         stripe_index += mirror_num - 1;
4609                 else {
4610                         int old_stripe_index = stripe_index;
4611                         stripe_index = find_live_mirror(fs_info, map,
4612                                               stripe_index,
4613                                               map->sub_stripes, stripe_index +
4614                                               current->pid % map->sub_stripes,
4615                                               dev_replace_is_ongoing);
4616                         mirror_num = stripe_index - old_stripe_index + 1;
4617                 }
4618
4619         } else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4620                                 BTRFS_BLOCK_GROUP_RAID6)) {
4621                 u64 tmp;
4622
4623                 if (bbio_ret && ((rw & REQ_WRITE) || mirror_num > 1)
4624                     && raid_map_ret) {
4625                         int i, rot;
4626
4627                         /* push stripe_nr back to the start of the full stripe */
4628                         stripe_nr = raid56_full_stripe_start;
4629                         do_div(stripe_nr, stripe_len);
4630
4631                         stripe_index = do_div(stripe_nr, nr_data_stripes(map));
4632
4633                         /* RAID[56] write or recovery. Return all stripes */
4634                         num_stripes = map->num_stripes;
4635                         max_errors = nr_parity_stripes(map);
4636
4637                         raid_map = kmalloc(sizeof(u64) * num_stripes,
4638                                            GFP_NOFS);
4639                         if (!raid_map) {
4640                                 ret = -ENOMEM;
4641                                 goto out;
4642                         }
4643
4644                         /* Work out the disk rotation on this stripe-set */
4645                         tmp = stripe_nr;
4646                         rot = do_div(tmp, num_stripes);
4647
4648                         /* Fill in the logical address of each stripe */
4649                         tmp = stripe_nr * nr_data_stripes(map);
4650                         for (i = 0; i < nr_data_stripes(map); i++)
4651                                 raid_map[(i+rot) % num_stripes] =
4652                                         em->start + (tmp + i) * map->stripe_len;
4653
4654                         raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
4655                         if (map->type & BTRFS_BLOCK_GROUP_RAID6)
4656                                 raid_map[(i+rot+1) % num_stripes] =
4657                                         RAID6_Q_STRIPE;
4658
4659                         *length = map->stripe_len;
4660                         stripe_index = 0;
4661                         stripe_offset = 0;
4662                 } else {
4663                         /*
4664                          * Mirror #0 or #1 means the original data block.
4665                          * Mirror #2 is RAID5 parity block.
4666                          * Mirror #3 is RAID6 Q block.
4667                          */
4668                         stripe_index = do_div(stripe_nr, nr_data_stripes(map));
4669                         if (mirror_num > 1)
4670                                 stripe_index = nr_data_stripes(map) +
4671                                                 mirror_num - 2;
4672
4673                         /* We distribute the parity blocks across stripes */
4674                         tmp = stripe_nr + stripe_index;
4675                         stripe_index = do_div(tmp, map->num_stripes);
4676                 }
4677         } else {
4678                 /*
4679                  * after this do_div call, stripe_nr is the number of stripes
4680                  * on this device we have to walk to find the data, and
4681                  * stripe_index is the number of our device in the stripe array
4682                  */
4683                 stripe_index = do_div(stripe_nr, map->num_stripes);
4684                 mirror_num = stripe_index + 1;
4685         }
4686         BUG_ON(stripe_index >= map->num_stripes);
4687
4688         num_alloc_stripes = num_stripes;
4689         if (dev_replace_is_ongoing) {
4690                 if (rw & (REQ_WRITE | REQ_DISCARD))
4691                         num_alloc_stripes <<= 1;
4692                 if (rw & REQ_GET_READ_MIRRORS)
4693                         num_alloc_stripes++;
4694         }
4695         bbio = kzalloc(btrfs_bio_size(num_alloc_stripes), GFP_NOFS);
4696         if (!bbio) {
4697                 ret = -ENOMEM;
4698                 goto out;
4699         }
4700         atomic_set(&bbio->error, 0);
4701
4702         if (rw & REQ_DISCARD) {
4703                 int factor = 0;
4704                 int sub_stripes = 0;
4705                 u64 stripes_per_dev = 0;
4706                 u32 remaining_stripes = 0;
4707                 u32 last_stripe = 0;
4708
4709                 if (map->type &
4710                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
4711                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4712                                 sub_stripes = 1;
4713                         else
4714                                 sub_stripes = map->sub_stripes;
4715
4716                         factor = map->num_stripes / sub_stripes;
4717                         stripes_per_dev = div_u64_rem(stripe_nr_end -
4718                                                       stripe_nr_orig,
4719                                                       factor,
4720                                                       &remaining_stripes);
4721                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
4722                         last_stripe *= sub_stripes;
4723                 }
4724
4725                 for (i = 0; i < num_stripes; i++) {
4726                         bbio->stripes[i].physical =
4727                                 map->stripes[stripe_index].physical +
4728                                 stripe_offset + stripe_nr * map->stripe_len;
4729                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
4730
4731                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
4732                                          BTRFS_BLOCK_GROUP_RAID10)) {
4733                                 bbio->stripes[i].length = stripes_per_dev *
4734                                                           map->stripe_len;
4735
4736                                 if (i / sub_stripes < remaining_stripes)
4737                                         bbio->stripes[i].length +=
4738                                                 map->stripe_len;
4739
4740                                 /*
4741                                  * Special for the first stripe and
4742                                  * the last stripe:
4743                                  *
4744                                  * |-------|...|-------|
4745                                  *     |----------|
4746                                  *    off     end_off
4747                                  */
4748                                 if (i < sub_stripes)
4749                                         bbio->stripes[i].length -=
4750                                                 stripe_offset;
4751
4752                                 if (stripe_index >= last_stripe &&
4753                                     stripe_index <= (last_stripe +
4754                                                      sub_stripes - 1))
4755                                         bbio->stripes[i].length -=
4756                                                 stripe_end_offset;
4757
4758                                 if (i == sub_stripes - 1)
4759                                         stripe_offset = 0;
4760                         } else
4761                                 bbio->stripes[i].length = *length;
4762
4763                         stripe_index++;
4764                         if (stripe_index == map->num_stripes) {
4765                                 /* This could only happen for RAID0/10 */
4766                                 stripe_index = 0;
4767                                 stripe_nr++;
4768                         }
4769                 }
4770         } else {
4771                 for (i = 0; i < num_stripes; i++) {
4772                         bbio->stripes[i].physical =
4773                                 map->stripes[stripe_index].physical +
4774                                 stripe_offset +
4775                                 stripe_nr * map->stripe_len;
4776                         bbio->stripes[i].dev =
4777                                 map->stripes[stripe_index].dev;
4778                         stripe_index++;
4779                 }
4780         }
4781
4782         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) {
4783                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4784                                  BTRFS_BLOCK_GROUP_RAID10 |
4785                                  BTRFS_BLOCK_GROUP_RAID5 |
4786                                  BTRFS_BLOCK_GROUP_DUP)) {
4787                         max_errors = 1;
4788                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
4789                         max_errors = 2;
4790                 }
4791         }
4792
4793         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
4794             dev_replace->tgtdev != NULL) {
4795                 int index_where_to_add;
4796                 u64 srcdev_devid = dev_replace->srcdev->devid;
4797
4798                 /*
4799                  * duplicate the write operations while the dev replace
4800                  * procedure is running. Since the copying of the old disk
4801                  * to the new disk takes place at run time while the
4802                  * filesystem is mounted writable, the regular write
4803                  * operations to the old disk have to be duplicated to go
4804                  * to the new disk as well.
4805                  * Note that device->missing is handled by the caller, and
4806                  * that the write to the old disk is already set up in the
4807                  * stripes array.
4808                  */
4809                 index_where_to_add = num_stripes;
4810                 for (i = 0; i < num_stripes; i++) {
4811                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4812                                 /* write to new disk, too */
4813                                 struct btrfs_bio_stripe *new =
4814                                         bbio->stripes + index_where_to_add;
4815                                 struct btrfs_bio_stripe *old =
4816                                         bbio->stripes + i;
4817
4818                                 new->physical = old->physical;
4819                                 new->length = old->length;
4820                                 new->dev = dev_replace->tgtdev;
4821                                 index_where_to_add++;
4822                                 max_errors++;
4823                         }
4824                 }
4825                 num_stripes = index_where_to_add;
4826         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
4827                    dev_replace->tgtdev != NULL) {
4828                 u64 srcdev_devid = dev_replace->srcdev->devid;
4829                 int index_srcdev = 0;
4830                 int found = 0;
4831                 u64 physical_of_found = 0;
4832
4833                 /*
4834                  * During the dev-replace procedure, the target drive can
4835                  * also be used to read data in case it is needed to repair
4836                  * a corrupt block elsewhere. This is possible if the
4837                  * requested area is left of the left cursor. In this area,
4838                  * the target drive is a full copy of the source drive.
4839                  */
4840                 for (i = 0; i < num_stripes; i++) {
4841                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4842                                 /*
4843                                  * In case of DUP, in order to keep it
4844                                  * simple, only add the mirror with the
4845                                  * lowest physical address
4846                                  */
4847                                 if (found &&
4848                                     physical_of_found <=
4849                                      bbio->stripes[i].physical)
4850                                         continue;
4851                                 index_srcdev = i;
4852                                 found = 1;
4853                                 physical_of_found = bbio->stripes[i].physical;
4854                         }
4855                 }
4856                 if (found) {
4857                         u64 length = map->stripe_len;
4858
4859                         if (physical_of_found + length <=
4860                             dev_replace->cursor_left) {
4861                                 struct btrfs_bio_stripe *tgtdev_stripe =
4862                                         bbio->stripes + num_stripes;
4863
4864                                 tgtdev_stripe->physical = physical_of_found;
4865                                 tgtdev_stripe->length =
4866                                         bbio->stripes[index_srcdev].length;
4867                                 tgtdev_stripe->dev = dev_replace->tgtdev;
4868
4869                                 num_stripes++;
4870                         }
4871                 }
4872         }
4873
4874         *bbio_ret = bbio;
4875         bbio->num_stripes = num_stripes;
4876         bbio->max_errors = max_errors;
4877         bbio->mirror_num = mirror_num;
4878
4879         /*
4880          * this is the case that REQ_READ && dev_replace_is_ongoing &&
4881          * mirror_num == num_stripes + 1 && dev_replace target drive is
4882          * available as a mirror
4883          */
4884         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
4885                 WARN_ON(num_stripes > 1);
4886                 bbio->stripes[0].dev = dev_replace->tgtdev;
4887                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
4888                 bbio->mirror_num = map->num_stripes + 1;
4889         }
4890         if (raid_map) {
4891                 sort_parity_stripes(bbio, raid_map);
4892                 *raid_map_ret = raid_map;
4893         }
4894 out:
4895         if (dev_replace_is_ongoing)
4896                 btrfs_dev_replace_unlock(dev_replace);
4897         free_extent_map(em);
4898         return ret;
4899 }
4900
4901 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4902                       u64 logical, u64 *length,
4903                       struct btrfs_bio **bbio_ret, int mirror_num)
4904 {
4905         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
4906                                  mirror_num, NULL);
4907 }
4908
4909 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
4910                      u64 chunk_start, u64 physical, u64 devid,
4911                      u64 **logical, int *naddrs, int *stripe_len)
4912 {
4913         struct extent_map_tree *em_tree = &map_tree->map_tree;
4914         struct extent_map *em;
4915         struct map_lookup *map;
4916         u64 *buf;
4917         u64 bytenr;
4918         u64 length;
4919         u64 stripe_nr;
4920         u64 rmap_len;
4921         int i, j, nr = 0;
4922
4923         read_lock(&em_tree->lock);
4924         em = lookup_extent_mapping(em_tree, chunk_start, 1);
4925         read_unlock(&em_tree->lock);
4926
4927         BUG_ON(!em || em->start != chunk_start);
4928         map = (struct map_lookup *)em->bdev;
4929
4930         length = em->len;
4931         rmap_len = map->stripe_len;
4932
4933         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4934                 do_div(length, map->num_stripes / map->sub_stripes);
4935         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4936                 do_div(length, map->num_stripes);
4937         else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4938                               BTRFS_BLOCK_GROUP_RAID6)) {
4939                 do_div(length, nr_data_stripes(map));
4940                 rmap_len = map->stripe_len * nr_data_stripes(map);
4941         }
4942
4943         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
4944         BUG_ON(!buf); /* -ENOMEM */
4945
4946         for (i = 0; i < map->num_stripes; i++) {
4947                 if (devid && map->stripes[i].dev->devid != devid)
4948                         continue;
4949                 if (map->stripes[i].physical > physical ||
4950                     map->stripes[i].physical + length <= physical)
4951                         continue;
4952
4953                 stripe_nr = physical - map->stripes[i].physical;
4954                 do_div(stripe_nr, map->stripe_len);
4955
4956                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4957                         stripe_nr = stripe_nr * map->num_stripes + i;
4958                         do_div(stripe_nr, map->sub_stripes);
4959                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4960                         stripe_nr = stripe_nr * map->num_stripes + i;
4961                 } /* else if RAID[56], multiply by nr_data_stripes().
4962                    * Alternatively, just use rmap_len below instead of
4963                    * map->stripe_len */
4964
4965                 bytenr = chunk_start + stripe_nr * rmap_len;
4966                 WARN_ON(nr >= map->num_stripes);
4967                 for (j = 0; j < nr; j++) {
4968                         if (buf[j] == bytenr)
4969                                 break;
4970                 }
4971                 if (j == nr) {
4972                         WARN_ON(nr >= map->num_stripes);
4973                         buf[nr++] = bytenr;
4974                 }
4975         }
4976
4977         *logical = buf;
4978         *naddrs = nr;
4979         *stripe_len = rmap_len;
4980
4981         free_extent_map(em);
4982         return 0;
4983 }
4984
4985 static void *merge_stripe_index_into_bio_private(void *bi_private,
4986                                                  unsigned int stripe_index)
4987 {
4988         /*
4989          * with single, dup, RAID0, RAID1 and RAID10, stripe_index is
4990          * at most 1.
4991          * The alternative solution (instead of stealing bits from the
4992          * pointer) would be to allocate an intermediate structure
4993          * that contains the old private pointer plus the stripe_index.
4994          */
4995         BUG_ON((((uintptr_t)bi_private) & 3) != 0);
4996         BUG_ON(stripe_index > 3);
4997         return (void *)(((uintptr_t)bi_private) | stripe_index);
4998 }
4999
5000 static struct btrfs_bio *extract_bbio_from_bio_private(void *bi_private)
5001 {
5002         return (struct btrfs_bio *)(((uintptr_t)bi_private) & ~((uintptr_t)3));
5003 }
5004
5005 static unsigned int extract_stripe_index_from_bio_private(void *bi_private)
5006 {
5007         return (unsigned int)((uintptr_t)bi_private) & 3;
5008 }
5009
5010 static void btrfs_end_bio(struct bio *bio, int err)
5011 {
5012         struct btrfs_bio *bbio = extract_bbio_from_bio_private(bio->bi_private);
5013         int is_orig_bio = 0;
5014
5015         if (err) {
5016                 atomic_inc(&bbio->error);
5017                 if (err == -EIO || err == -EREMOTEIO) {
5018                         unsigned int stripe_index =
5019                                 extract_stripe_index_from_bio_private(
5020                                         bio->bi_private);
5021                         struct btrfs_device *dev;
5022
5023                         BUG_ON(stripe_index >= bbio->num_stripes);
5024                         dev = bbio->stripes[stripe_index].dev;
5025                         if (dev->bdev) {
5026                                 if (bio->bi_rw & WRITE)
5027                                         btrfs_dev_stat_inc(dev,
5028                                                 BTRFS_DEV_STAT_WRITE_ERRS);
5029                                 else
5030                                         btrfs_dev_stat_inc(dev,
5031                                                 BTRFS_DEV_STAT_READ_ERRS);
5032                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
5033                                         btrfs_dev_stat_inc(dev,
5034                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
5035                                 btrfs_dev_stat_print_on_error(dev);
5036                         }
5037                 }
5038         }
5039
5040         if (bio == bbio->orig_bio)
5041                 is_orig_bio = 1;
5042
5043         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5044                 if (!is_orig_bio) {
5045                         bio_put(bio);
5046                         bio = bbio->orig_bio;
5047                 }
5048                 bio->bi_private = bbio->private;
5049                 bio->bi_end_io = bbio->end_io;
5050                 bio->bi_bdev = (struct block_device *)
5051                                         (unsigned long)bbio->mirror_num;
5052                 /* only send an error to the higher layers if it is
5053                  * beyond the tolerance of the btrfs bio
5054                  */
5055                 if (atomic_read(&bbio->error) > bbio->max_errors) {
5056                         err = -EIO;
5057                 } else {
5058                         /*
5059                          * this bio is actually up to date, we didn't
5060                          * go over the max number of errors
5061                          */
5062                         set_bit(BIO_UPTODATE, &bio->bi_flags);
5063                         err = 0;
5064                 }
5065                 kfree(bbio);
5066
5067                 bio_endio(bio, err);
5068         } else if (!is_orig_bio) {
5069                 bio_put(bio);
5070         }
5071 }
5072
5073 struct async_sched {
5074         struct bio *bio;
5075         int rw;
5076         struct btrfs_fs_info *info;
5077         struct btrfs_work work;
5078 };
5079
5080 /*
5081  * see run_scheduled_bios for a description of why bios are collected for
5082  * async submit.
5083  *
5084  * This will add one bio to the pending list for a device and make sure
5085  * the work struct is scheduled.
5086  */
5087 noinline void btrfs_schedule_bio(struct btrfs_root *root,
5088                                  struct btrfs_device *device,
5089                                  int rw, struct bio *bio)
5090 {
5091         int should_queue = 1;
5092         struct btrfs_pending_bios *pending_bios;
5093
5094         if (device->missing || !device->bdev) {
5095                 bio_endio(bio, -EIO);
5096                 return;
5097         }
5098
5099         /* don't bother with additional async steps for reads, right now */
5100         if (!(rw & REQ_WRITE)) {
5101                 bio_get(bio);
5102                 btrfsic_submit_bio(rw, bio);
5103                 bio_put(bio);
5104                 return;
5105         }
5106
5107         /*
5108          * nr_async_bios allows us to reliably return congestion to the
5109          * higher layers.  Otherwise, the async bio makes it appear we have
5110          * made progress against dirty pages when we've really just put it
5111          * on a queue for later
5112          */
5113         atomic_inc(&root->fs_info->nr_async_bios);
5114         WARN_ON(bio->bi_next);
5115         bio->bi_next = NULL;
5116         bio->bi_rw |= rw;
5117
5118         spin_lock(&device->io_lock);
5119         if (bio->bi_rw & REQ_SYNC)
5120                 pending_bios = &device->pending_sync_bios;
5121         else
5122                 pending_bios = &device->pending_bios;
5123
5124         if (pending_bios->tail)
5125                 pending_bios->tail->bi_next = bio;
5126
5127         pending_bios->tail = bio;
5128         if (!pending_bios->head)
5129                 pending_bios->head = bio;
5130         if (device->running_pending)
5131                 should_queue = 0;
5132
5133         spin_unlock(&device->io_lock);
5134
5135         if (should_queue)
5136                 btrfs_queue_worker(&root->fs_info->submit_workers,
5137                                    &device->work);
5138 }
5139
5140 static int bio_size_ok(struct block_device *bdev, struct bio *bio,
5141                        sector_t sector)
5142 {
5143         struct bio_vec *prev;
5144         struct request_queue *q = bdev_get_queue(bdev);
5145         unsigned short max_sectors = queue_max_sectors(q);
5146         struct bvec_merge_data bvm = {
5147                 .bi_bdev = bdev,
5148                 .bi_sector = sector,
5149                 .bi_rw = bio->bi_rw,
5150         };
5151
5152         if (bio->bi_vcnt == 0) {
5153                 WARN_ON(1);
5154                 return 1;
5155         }
5156
5157         prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
5158         if ((bio->bi_size >> 9) > max_sectors)
5159                 return 0;
5160
5161         if (!q->merge_bvec_fn)
5162                 return 1;
5163
5164         bvm.bi_size = bio->bi_size - prev->bv_len;
5165         if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)
5166                 return 0;
5167         return 1;
5168 }
5169
5170 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
5171                               struct bio *bio, u64 physical, int dev_nr,
5172                               int rw, int async)
5173 {
5174         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
5175
5176         bio->bi_private = bbio;
5177         bio->bi_private = merge_stripe_index_into_bio_private(
5178                         bio->bi_private, (unsigned int)dev_nr);
5179         bio->bi_end_io = btrfs_end_bio;
5180         bio->bi_sector = physical >> 9;
5181 #ifdef DEBUG
5182         {
5183                 struct rcu_string *name;
5184
5185                 rcu_read_lock();
5186                 name = rcu_dereference(dev->name);
5187                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
5188                          "(%s id %llu), size=%u\n", rw,
5189                          (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
5190                          name->str, dev->devid, bio->bi_size);
5191                 rcu_read_unlock();
5192         }
5193 #endif
5194         bio->bi_bdev = dev->bdev;
5195         if (async)
5196                 btrfs_schedule_bio(root, dev, rw, bio);
5197         else
5198                 btrfsic_submit_bio(rw, bio);
5199 }
5200
5201 static int breakup_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
5202                               struct bio *first_bio, struct btrfs_device *dev,
5203                               int dev_nr, int rw, int async)
5204 {
5205         struct bio_vec *bvec = first_bio->bi_io_vec;
5206         struct bio *bio;
5207         int nr_vecs = bio_get_nr_vecs(dev->bdev);
5208         u64 physical = bbio->stripes[dev_nr].physical;
5209
5210 again:
5211         bio = btrfs_bio_alloc(dev->bdev, physical >> 9, nr_vecs, GFP_NOFS);
5212         if (!bio)
5213                 return -ENOMEM;
5214
5215         while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {
5216                 if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,
5217                                  bvec->bv_offset) < bvec->bv_len) {
5218                         u64 len = bio->bi_size;
5219
5220                         atomic_inc(&bbio->stripes_pending);
5221                         submit_stripe_bio(root, bbio, bio, physical, dev_nr,
5222                                           rw, async);
5223                         physical += len;
5224                         goto again;
5225                 }
5226                 bvec++;
5227         }
5228
5229         submit_stripe_bio(root, bbio, bio, physical, dev_nr, rw, async);
5230         return 0;
5231 }
5232
5233 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
5234 {
5235         atomic_inc(&bbio->error);
5236         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5237                 bio->bi_private = bbio->private;
5238                 bio->bi_end_io = bbio->end_io;
5239                 bio->bi_bdev = (struct block_device *)
5240                         (unsigned long)bbio->mirror_num;
5241                 bio->bi_sector = logical >> 9;
5242                 kfree(bbio);
5243                 bio_endio(bio, -EIO);
5244         }
5245 }
5246
5247 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
5248                   int mirror_num, int async_submit)
5249 {
5250         struct btrfs_device *dev;
5251         struct bio *first_bio = bio;
5252         u64 logical = (u64)bio->bi_sector << 9;
5253         u64 length = 0;
5254         u64 map_length;
5255         u64 *raid_map = NULL;
5256         int ret;
5257         int dev_nr = 0;
5258         int total_devs = 1;
5259         struct btrfs_bio *bbio = NULL;
5260
5261         length = bio->bi_size;
5262         map_length = length;
5263
5264         ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
5265                               mirror_num, &raid_map);
5266         if (ret) /* -ENOMEM */
5267                 return ret;
5268
5269         total_devs = bbio->num_stripes;
5270         bbio->orig_bio = first_bio;
5271         bbio->private = first_bio->bi_private;
5272         bbio->end_io = first_bio->bi_end_io;
5273         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
5274
5275         if (raid_map) {
5276                 /* In this case, map_length has been set to the length of
5277                    a single stripe; not the whole write */
5278                 if (rw & WRITE) {
5279                         return raid56_parity_write(root, bio, bbio,
5280                                                    raid_map, map_length);
5281                 } else {
5282                         return raid56_parity_recover(root, bio, bbio,
5283                                                      raid_map, map_length,
5284                                                      mirror_num);
5285                 }
5286         }
5287
5288         if (map_length < length) {
5289                 printk(KERN_CRIT "btrfs: mapping failed logical %llu bio len %llu "
5290                        "len %llu\n", (unsigned long long)logical,
5291                        (unsigned long long)length,
5292                        (unsigned long long)map_length);
5293                 BUG();
5294         }
5295
5296         while (dev_nr < total_devs) {
5297                 dev = bbio->stripes[dev_nr].dev;
5298                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
5299                         bbio_error(bbio, first_bio, logical);
5300                         dev_nr++;
5301                         continue;
5302                 }
5303
5304                 /*
5305                  * Check and see if we're ok with this bio based on it's size
5306                  * and offset with the given device.
5307                  */
5308                 if (!bio_size_ok(dev->bdev, first_bio,
5309                                  bbio->stripes[dev_nr].physical >> 9)) {
5310                         ret = breakup_stripe_bio(root, bbio, first_bio, dev,
5311                                                  dev_nr, rw, async_submit);
5312                         BUG_ON(ret);
5313                         dev_nr++;
5314                         continue;
5315                 }
5316
5317                 if (dev_nr < total_devs - 1) {
5318                         bio = bio_clone(first_bio, GFP_NOFS);
5319                         BUG_ON(!bio); /* -ENOMEM */
5320                 } else {
5321                         bio = first_bio;
5322                 }
5323
5324                 submit_stripe_bio(root, bbio, bio,
5325                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
5326                                   async_submit);
5327                 dev_nr++;
5328         }
5329         return 0;
5330 }
5331
5332 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
5333                                        u8 *uuid, u8 *fsid)
5334 {
5335         struct btrfs_device *device;
5336         struct btrfs_fs_devices *cur_devices;
5337
5338         cur_devices = fs_info->fs_devices;
5339         while (cur_devices) {
5340                 if (!fsid ||
5341                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
5342                         device = __find_device(&cur_devices->devices,
5343                                                devid, uuid);
5344                         if (device)
5345                                 return device;
5346                 }
5347                 cur_devices = cur_devices->seed;
5348         }
5349         return NULL;
5350 }
5351
5352 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
5353                                             u64 devid, u8 *dev_uuid)
5354 {
5355         struct btrfs_device *device;
5356         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
5357
5358         device = kzalloc(sizeof(*device), GFP_NOFS);
5359         if (!device)
5360                 return NULL;
5361         list_add(&device->dev_list,
5362                  &fs_devices->devices);
5363         device->dev_root = root->fs_info->dev_root;
5364         device->devid = devid;
5365         device->work.func = pending_bios_fn;
5366         device->fs_devices = fs_devices;
5367         device->missing = 1;
5368         fs_devices->num_devices++;
5369         fs_devices->missing_devices++;
5370         spin_lock_init(&device->io_lock);
5371         INIT_LIST_HEAD(&device->dev_alloc_list);
5372         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
5373         return device;
5374 }
5375
5376 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
5377                           struct extent_buffer *leaf,
5378                           struct btrfs_chunk *chunk)
5379 {
5380         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
5381         struct map_lookup *map;
5382         struct extent_map *em;
5383         u64 logical;
5384         u64 length;
5385         u64 devid;
5386         u8 uuid[BTRFS_UUID_SIZE];
5387         int num_stripes;
5388         int ret;
5389         int i;
5390
5391         logical = key->offset;
5392         length = btrfs_chunk_length(leaf, chunk);
5393
5394         read_lock(&map_tree->map_tree.lock);
5395         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
5396         read_unlock(&map_tree->map_tree.lock);
5397
5398         /* already mapped? */
5399         if (em && em->start <= logical && em->start + em->len > logical) {
5400                 free_extent_map(em);
5401                 return 0;
5402         } else if (em) {
5403                 free_extent_map(em);
5404         }
5405
5406         em = alloc_extent_map();
5407         if (!em)
5408                 return -ENOMEM;
5409         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
5410         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
5411         if (!map) {
5412                 free_extent_map(em);
5413                 return -ENOMEM;
5414         }
5415
5416         em->bdev = (struct block_device *)map;
5417         em->start = logical;
5418         em->len = length;
5419         em->orig_start = 0;
5420         em->block_start = 0;
5421         em->block_len = em->len;
5422
5423         map->num_stripes = num_stripes;
5424         map->io_width = btrfs_chunk_io_width(leaf, chunk);
5425         map->io_align = btrfs_chunk_io_align(leaf, chunk);
5426         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
5427         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
5428         map->type = btrfs_chunk_type(leaf, chunk);
5429         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
5430         for (i = 0; i < num_stripes; i++) {
5431                 map->stripes[i].physical =
5432                         btrfs_stripe_offset_nr(leaf, chunk, i);
5433                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
5434                 read_extent_buffer(leaf, uuid, (unsigned long)
5435                                    btrfs_stripe_dev_uuid_nr(chunk, i),
5436                                    BTRFS_UUID_SIZE);
5437                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
5438                                                         uuid, NULL);
5439                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
5440                         kfree(map);
5441                         free_extent_map(em);
5442                         return -EIO;
5443                 }
5444                 if (!map->stripes[i].dev) {
5445                         map->stripes[i].dev =
5446                                 add_missing_dev(root, devid, uuid);
5447                         if (!map->stripes[i].dev) {
5448                                 kfree(map);
5449                                 free_extent_map(em);
5450                                 return -EIO;
5451                         }
5452                 }
5453                 map->stripes[i].dev->in_fs_metadata = 1;
5454         }
5455
5456         write_lock(&map_tree->map_tree.lock);
5457         ret = add_extent_mapping(&map_tree->map_tree, em);
5458         write_unlock(&map_tree->map_tree.lock);
5459         BUG_ON(ret); /* Tree corruption */
5460         free_extent_map(em);
5461
5462         return 0;
5463 }
5464
5465 static void fill_device_from_item(struct extent_buffer *leaf,
5466                                  struct btrfs_dev_item *dev_item,
5467                                  struct btrfs_device *device)
5468 {
5469         unsigned long ptr;
5470
5471         device->devid = btrfs_device_id(leaf, dev_item);
5472         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
5473         device->total_bytes = device->disk_total_bytes;
5474         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
5475         device->type = btrfs_device_type(leaf, dev_item);
5476         device->io_align = btrfs_device_io_align(leaf, dev_item);
5477         device->io_width = btrfs_device_io_width(leaf, dev_item);
5478         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
5479         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
5480         device->is_tgtdev_for_dev_replace = 0;
5481
5482         ptr = (unsigned long)btrfs_device_uuid(dev_item);
5483         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
5484 }
5485
5486 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
5487 {
5488         struct btrfs_fs_devices *fs_devices;
5489         int ret;
5490
5491         BUG_ON(!mutex_is_locked(&uuid_mutex));
5492
5493         fs_devices = root->fs_info->fs_devices->seed;
5494         while (fs_devices) {
5495                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
5496                         ret = 0;
5497                         goto out;
5498                 }
5499                 fs_devices = fs_devices->seed;
5500         }
5501
5502         fs_devices = find_fsid(fsid);
5503         if (!fs_devices) {
5504                 ret = -ENOENT;
5505                 goto out;
5506         }
5507
5508         fs_devices = clone_fs_devices(fs_devices);
5509         if (IS_ERR(fs_devices)) {
5510                 ret = PTR_ERR(fs_devices);
5511                 goto out;
5512         }
5513
5514         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
5515                                    root->fs_info->bdev_holder);
5516         if (ret) {
5517                 free_fs_devices(fs_devices);
5518                 goto out;
5519         }
5520
5521         if (!fs_devices->seeding) {
5522                 __btrfs_close_devices(fs_devices);
5523                 free_fs_devices(fs_devices);
5524                 ret = -EINVAL;
5525                 goto out;
5526         }
5527
5528         fs_devices->seed = root->fs_info->fs_devices->seed;
5529         root->fs_info->fs_devices->seed = fs_devices;
5530 out:
5531         return ret;
5532 }
5533
5534 static int read_one_dev(struct btrfs_root *root,
5535                         struct extent_buffer *leaf,
5536                         struct btrfs_dev_item *dev_item)
5537 {
5538         struct btrfs_device *device;
5539         u64 devid;
5540         int ret;
5541         u8 fs_uuid[BTRFS_UUID_SIZE];
5542         u8 dev_uuid[BTRFS_UUID_SIZE];
5543
5544         devid = btrfs_device_id(leaf, dev_item);
5545         read_extent_buffer(leaf, dev_uuid,
5546                            (unsigned long)btrfs_device_uuid(dev_item),
5547                            BTRFS_UUID_SIZE);
5548         read_extent_buffer(leaf, fs_uuid,
5549                            (unsigned long)btrfs_device_fsid(dev_item),
5550                            BTRFS_UUID_SIZE);
5551
5552         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
5553                 ret = open_seed_devices(root, fs_uuid);
5554                 if (ret && !btrfs_test_opt(root, DEGRADED))
5555                         return ret;
5556         }
5557
5558         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
5559         if (!device || !device->bdev) {
5560                 if (!btrfs_test_opt(root, DEGRADED))
5561                         return -EIO;
5562
5563                 if (!device) {
5564                         printk(KERN_WARNING "warning devid %llu missing\n",
5565                                (unsigned long long)devid);
5566                         device = add_missing_dev(root, devid, dev_uuid);
5567                         if (!device)
5568                                 return -ENOMEM;
5569                 } else if (!device->missing) {
5570                         /*
5571                          * this happens when a device that was properly setup
5572                          * in the device info lists suddenly goes bad.
5573                          * device->bdev is NULL, and so we have to set
5574                          * device->missing to one here
5575                          */
5576                         root->fs_info->fs_devices->missing_devices++;
5577                         device->missing = 1;
5578                 }
5579         }
5580
5581         if (device->fs_devices != root->fs_info->fs_devices) {
5582                 BUG_ON(device->writeable);
5583                 if (device->generation !=
5584                     btrfs_device_generation(leaf, dev_item))
5585                         return -EINVAL;
5586         }
5587
5588         fill_device_from_item(leaf, dev_item, device);
5589         device->dev_root = root->fs_info->dev_root;
5590         device->in_fs_metadata = 1;
5591         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
5592                 device->fs_devices->total_rw_bytes += device->total_bytes;
5593                 spin_lock(&root->fs_info->free_chunk_lock);
5594                 root->fs_info->free_chunk_space += device->total_bytes -
5595                         device->bytes_used;
5596                 spin_unlock(&root->fs_info->free_chunk_lock);
5597         }
5598         ret = 0;
5599         return ret;
5600 }
5601
5602 int btrfs_read_sys_array(struct btrfs_root *root)
5603 {
5604         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
5605         struct extent_buffer *sb;
5606         struct btrfs_disk_key *disk_key;
5607         struct btrfs_chunk *chunk;
5608         u8 *ptr;
5609         unsigned long sb_ptr;
5610         int ret = 0;
5611         u32 num_stripes;
5612         u32 array_size;
5613         u32 len = 0;
5614         u32 cur;
5615         struct btrfs_key key;
5616
5617         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
5618                                           BTRFS_SUPER_INFO_SIZE);
5619         if (!sb)
5620                 return -ENOMEM;
5621         btrfs_set_buffer_uptodate(sb);
5622         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
5623         /*
5624          * The sb extent buffer is artifical and just used to read the system array.
5625          * btrfs_set_buffer_uptodate() call does not properly mark all it's
5626          * pages up-to-date when the page is larger: extent does not cover the
5627          * whole page and consequently check_page_uptodate does not find all
5628          * the page's extents up-to-date (the hole beyond sb),
5629          * write_extent_buffer then triggers a WARN_ON.
5630          *
5631          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
5632          * but sb spans only this function. Add an explicit SetPageUptodate call
5633          * to silence the warning eg. on PowerPC 64.
5634          */
5635         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
5636                 SetPageUptodate(sb->pages[0]);
5637
5638         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
5639         array_size = btrfs_super_sys_array_size(super_copy);
5640
5641         ptr = super_copy->sys_chunk_array;
5642         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
5643         cur = 0;
5644
5645         while (cur < array_size) {
5646                 disk_key = (struct btrfs_disk_key *)ptr;
5647                 btrfs_disk_key_to_cpu(&key, disk_key);
5648
5649                 len = sizeof(*disk_key); ptr += len;
5650                 sb_ptr += len;
5651                 cur += len;
5652
5653                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
5654                         chunk = (struct btrfs_chunk *)sb_ptr;
5655                         ret = read_one_chunk(root, &key, sb, chunk);
5656                         if (ret)
5657                                 break;
5658                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
5659                         len = btrfs_chunk_item_size(num_stripes);
5660                 } else {
5661                         ret = -EIO;
5662                         break;
5663                 }
5664                 ptr += len;
5665                 sb_ptr += len;
5666                 cur += len;
5667         }
5668         free_extent_buffer(sb);
5669         return ret;
5670 }
5671
5672 int btrfs_read_chunk_tree(struct btrfs_root *root)
5673 {
5674         struct btrfs_path *path;
5675         struct extent_buffer *leaf;
5676         struct btrfs_key key;
5677         struct btrfs_key found_key;
5678         int ret;
5679         int slot;
5680
5681         root = root->fs_info->chunk_root;
5682
5683         path = btrfs_alloc_path();
5684         if (!path)
5685                 return -ENOMEM;
5686
5687         mutex_lock(&uuid_mutex);
5688         lock_chunks(root);
5689
5690         /* first we search for all of the device items, and then we
5691          * read in all of the chunk items.  This way we can create chunk
5692          * mappings that reference all of the devices that are afound
5693          */
5694         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
5695         key.offset = 0;
5696         key.type = 0;
5697 again:
5698         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5699         if (ret < 0)
5700                 goto error;
5701         while (1) {
5702                 leaf = path->nodes[0];
5703                 slot = path->slots[0];
5704                 if (slot >= btrfs_header_nritems(leaf)) {
5705                         ret = btrfs_next_leaf(root, path);
5706                         if (ret == 0)
5707                                 continue;
5708                         if (ret < 0)
5709                                 goto error;
5710                         break;
5711                 }
5712                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5713                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5714                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
5715                                 break;
5716                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
5717                                 struct btrfs_dev_item *dev_item;
5718                                 dev_item = btrfs_item_ptr(leaf, slot,
5719                                                   struct btrfs_dev_item);
5720                                 ret = read_one_dev(root, leaf, dev_item);
5721                                 if (ret)
5722                                         goto error;
5723                         }
5724                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
5725                         struct btrfs_chunk *chunk;
5726                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
5727                         ret = read_one_chunk(root, &found_key, leaf, chunk);
5728                         if (ret)
5729                                 goto error;
5730                 }
5731                 path->slots[0]++;
5732         }
5733         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5734                 key.objectid = 0;
5735                 btrfs_release_path(path);
5736                 goto again;
5737         }
5738         ret = 0;
5739 error:
5740         unlock_chunks(root);
5741         mutex_unlock(&uuid_mutex);
5742
5743         btrfs_free_path(path);
5744         return ret;
5745 }
5746
5747 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
5748 {
5749         int i;
5750
5751         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5752                 btrfs_dev_stat_reset(dev, i);
5753 }
5754
5755 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
5756 {
5757         struct btrfs_key key;
5758         struct btrfs_key found_key;
5759         struct btrfs_root *dev_root = fs_info->dev_root;
5760         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5761         struct extent_buffer *eb;
5762         int slot;
5763         int ret = 0;
5764         struct btrfs_device *device;
5765         struct btrfs_path *path = NULL;
5766         int i;
5767
5768         path = btrfs_alloc_path();
5769         if (!path) {
5770                 ret = -ENOMEM;
5771                 goto out;
5772         }
5773
5774         mutex_lock(&fs_devices->device_list_mutex);
5775         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5776                 int item_size;
5777                 struct btrfs_dev_stats_item *ptr;
5778
5779                 key.objectid = 0;
5780                 key.type = BTRFS_DEV_STATS_KEY;
5781                 key.offset = device->devid;
5782                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
5783                 if (ret) {
5784                         __btrfs_reset_dev_stats(device);
5785                         device->dev_stats_valid = 1;
5786                         btrfs_release_path(path);
5787                         continue;
5788                 }
5789                 slot = path->slots[0];
5790                 eb = path->nodes[0];
5791                 btrfs_item_key_to_cpu(eb, &found_key, slot);
5792                 item_size = btrfs_item_size_nr(eb, slot);
5793
5794                 ptr = btrfs_item_ptr(eb, slot,
5795                                      struct btrfs_dev_stats_item);
5796
5797                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5798                         if (item_size >= (1 + i) * sizeof(__le64))
5799                                 btrfs_dev_stat_set(device, i,
5800                                         btrfs_dev_stats_value(eb, ptr, i));
5801                         else
5802                                 btrfs_dev_stat_reset(device, i);
5803                 }
5804
5805                 device->dev_stats_valid = 1;
5806                 btrfs_dev_stat_print_on_load(device);
5807                 btrfs_release_path(path);
5808         }
5809         mutex_unlock(&fs_devices->device_list_mutex);
5810
5811 out:
5812         btrfs_free_path(path);
5813         return ret < 0 ? ret : 0;
5814 }
5815
5816 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
5817                                 struct btrfs_root *dev_root,
5818                                 struct btrfs_device *device)
5819 {
5820         struct btrfs_path *path;
5821         struct btrfs_key key;
5822         struct extent_buffer *eb;
5823         struct btrfs_dev_stats_item *ptr;
5824         int ret;
5825         int i;
5826
5827         key.objectid = 0;
5828         key.type = BTRFS_DEV_STATS_KEY;
5829         key.offset = device->devid;
5830
5831         path = btrfs_alloc_path();
5832         BUG_ON(!path);
5833         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
5834         if (ret < 0) {
5835                 printk_in_rcu(KERN_WARNING "btrfs: error %d while searching for dev_stats item for device %s!\n",
5836                               ret, rcu_str_deref(device->name));
5837                 goto out;
5838         }
5839
5840         if (ret == 0 &&
5841             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
5842                 /* need to delete old one and insert a new one */
5843                 ret = btrfs_del_item(trans, dev_root, path);
5844                 if (ret != 0) {
5845                         printk_in_rcu(KERN_WARNING "btrfs: delete too small dev_stats item for device %s failed %d!\n",
5846                                       rcu_str_deref(device->name), ret);
5847                         goto out;
5848                 }
5849                 ret = 1;
5850         }
5851
5852         if (ret == 1) {
5853                 /* need to insert a new item */
5854                 btrfs_release_path(path);
5855                 ret = btrfs_insert_empty_item(trans, dev_root, path,
5856                                               &key, sizeof(*ptr));
5857                 if (ret < 0) {
5858                         printk_in_rcu(KERN_WARNING "btrfs: insert dev_stats item for device %s failed %d!\n",
5859                                       rcu_str_deref(device->name), ret);
5860                         goto out;
5861                 }
5862         }
5863
5864         eb = path->nodes[0];
5865         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
5866         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5867                 btrfs_set_dev_stats_value(eb, ptr, i,
5868                                           btrfs_dev_stat_read(device, i));
5869         btrfs_mark_buffer_dirty(eb);
5870
5871 out:
5872         btrfs_free_path(path);
5873         return ret;
5874 }
5875
5876 /*
5877  * called from commit_transaction. Writes all changed device stats to disk.
5878  */
5879 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
5880                         struct btrfs_fs_info *fs_info)
5881 {
5882         struct btrfs_root *dev_root = fs_info->dev_root;
5883         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5884         struct btrfs_device *device;
5885         int ret = 0;
5886
5887         mutex_lock(&fs_devices->device_list_mutex);
5888         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5889                 if (!device->dev_stats_valid || !device->dev_stats_dirty)
5890                         continue;
5891
5892                 ret = update_dev_stat_item(trans, dev_root, device);
5893                 if (!ret)
5894                         device->dev_stats_dirty = 0;
5895         }
5896         mutex_unlock(&fs_devices->device_list_mutex);
5897
5898         return ret;
5899 }
5900
5901 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
5902 {
5903         btrfs_dev_stat_inc(dev, index);
5904         btrfs_dev_stat_print_on_error(dev);
5905 }
5906
5907 void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
5908 {
5909         if (!dev->dev_stats_valid)
5910                 return;
5911         printk_ratelimited_in_rcu(KERN_ERR
5912                            "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5913                            rcu_str_deref(dev->name),
5914                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5915                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5916                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5917                            btrfs_dev_stat_read(dev,
5918                                                BTRFS_DEV_STAT_CORRUPTION_ERRS),
5919                            btrfs_dev_stat_read(dev,
5920                                                BTRFS_DEV_STAT_GENERATION_ERRS));
5921 }
5922
5923 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
5924 {
5925         int i;
5926
5927         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5928                 if (btrfs_dev_stat_read(dev, i) != 0)
5929                         break;
5930         if (i == BTRFS_DEV_STAT_VALUES_MAX)
5931                 return; /* all values == 0, suppress message */
5932
5933         printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5934                rcu_str_deref(dev->name),
5935                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5936                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5937                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5938                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
5939                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
5940 }
5941
5942 int btrfs_get_dev_stats(struct btrfs_root *root,
5943                         struct btrfs_ioctl_get_dev_stats *stats)
5944 {
5945         struct btrfs_device *dev;
5946         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
5947         int i;
5948
5949         mutex_lock(&fs_devices->device_list_mutex);
5950         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
5951         mutex_unlock(&fs_devices->device_list_mutex);
5952
5953         if (!dev) {
5954                 printk(KERN_WARNING
5955                        "btrfs: get dev_stats failed, device not found\n");
5956                 return -ENODEV;
5957         } else if (!dev->dev_stats_valid) {
5958                 printk(KERN_WARNING
5959                        "btrfs: get dev_stats failed, not yet valid\n");
5960                 return -ENODEV;
5961         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
5962                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5963                         if (stats->nr_items > i)
5964                                 stats->values[i] =
5965                                         btrfs_dev_stat_read_and_reset(dev, i);
5966                         else
5967                                 btrfs_dev_stat_reset(dev, i);
5968                 }
5969         } else {
5970                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5971                         if (stats->nr_items > i)
5972                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
5973         }
5974         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
5975                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
5976         return 0;
5977 }
5978
5979 int btrfs_scratch_superblock(struct btrfs_device *device)
5980 {
5981         struct buffer_head *bh;
5982         struct btrfs_super_block *disk_super;
5983
5984         bh = btrfs_read_dev_super(device->bdev);
5985         if (!bh)
5986                 return -EINVAL;
5987         disk_super = (struct btrfs_super_block *)bh->b_data;
5988
5989         memset(&disk_super->magic, 0, sizeof(disk_super->magic));
5990         set_buffer_dirty(bh);
5991         sync_dirty_buffer(bh);
5992         brelse(bh);
5993
5994         return 0;
5995 }