fs/xfs/xfs_dquot.c

   1 /*
   2  * Copyright (c) 2000-2003 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_bit.h"
  21 #include "xfs_log.h"
  22 #include "xfs_trans.h"
  23 #include "xfs_sb.h"
  24 #include "xfs_ag.h"
  25 #include "xfs_alloc.h"
  26 #include "xfs_quota.h"
  27 #include "xfs_mount.h"
  28 #include "xfs_bmap_btree.h"
  29 #include "xfs_inode.h"
  30 #include "xfs_bmap.h"
  31 #include "xfs_rtalloc.h"
  32 #include "xfs_error.h"
  33 #include "xfs_itable.h"
  34 #include "xfs_attr.h"
  35 #include "xfs_buf_item.h"
  36 #include "xfs_trans_space.h"
  37 #include "xfs_trans_priv.h"
  38 #include "xfs_qm.h"
  39 #include "xfs_cksum.h"
  40 #include "xfs_trace.h"
  41
  42 /*
  43  * Lock order:
  44  *
  45  * ip->i_lock
  46  *   qi->qi_tree_lock
  47  *     dquot->q_qlock (xfs_dqlock() and friends)
  48  *       dquot->q_flush (xfs_dqflock() and friends)
  49  *       qi->qi_lru_lock
  50  *
  51  * If two dquots need to be locked the order is user before group/project,
  52  * otherwise by the lowest id first, see xfs_dqlock2.
  53  */
  54
  55 #ifdef DEBUG
  56 xfs_buftarg_t *xfs_dqerror_target;
  57 int xfs_do_dqerror;
  58 int xfs_dqreq_num;
  59 int xfs_dqerror_mod = 33;
  60 #endif
  61
  62 struct kmem_zone                *xfs_qm_dqtrxzone;
  63 static struct kmem_zone         *xfs_qm_dqzone;
  64
  65 static struct lock_class_key xfs_dquot_other_class;
  66
  67 /*
  68  * This is called to free all the memory associated with a dquot
  69  */
  70 void
  71 xfs_qm_dqdestroy(
  72         xfs_dquot_t     *dqp)
  73 {
  74         ASSERT(list_empty(&dqp->q_lru));
  75
  76         mutex_destroy(&dqp->q_qlock);
  77         kmem_zone_free(xfs_qm_dqzone, dqp);
  78
  79         XFS_STATS_DEC(xs_qm_dquot);
  80 }
  81
  82 /*
  83  * If default limits are in force, push them into the dquot now.
  84  * We overwrite the dquot limits only if they are zero and this
  85  * is not the root dquot.
  86  */
  87 void
  88 xfs_qm_adjust_dqlimits(
  89         struct xfs_mount        *mp,
  90         struct xfs_dquot        *dq)
  91 {
  92         struct xfs_quotainfo    *q = mp->m_quotainfo;
  93         struct xfs_disk_dquot   *d = &dq->q_core;
  94         int                     prealloc = 0;
  95
  96         ASSERT(d->d_id);
  97
  98         if (q->qi_bsoftlimit && !d->d_blk_softlimit) {
  99                 d->d_blk_softlimit = cpu_to_be64(q->qi_bsoftlimit);
 100                 prealloc = 1;
 101         }
 102         if (q->qi_bhardlimit && !d->d_blk_hardlimit) {
 103                 d->d_blk_hardlimit = cpu_to_be64(q->qi_bhardlimit);
 104                 prealloc = 1;
 105         }
 106         if (q->qi_isoftlimit && !d->d_ino_softlimit)
 107                 d->d_ino_softlimit = cpu_to_be64(q->qi_isoftlimit);
 108         if (q->qi_ihardlimit && !d->d_ino_hardlimit)
 109                 d->d_ino_hardlimit = cpu_to_be64(q->qi_ihardlimit);
 110         if (q->qi_rtbsoftlimit && !d->d_rtb_softlimit)
 111                 d->d_rtb_softlimit = cpu_to_be64(q->qi_rtbsoftlimit);
 112         if (q->qi_rtbhardlimit && !d->d_rtb_hardlimit)
 113                 d->d_rtb_hardlimit = cpu_to_be64(q->qi_rtbhardlimit);
 114
 115         if (prealloc)
 116                 xfs_dquot_set_prealloc_limits(dq);
 117 }
 118
 119 /*
 120  * Check the limits and timers of a dquot and start or reset timers
 121  * if necessary.
 122  * This gets called even when quota enforcement is OFF, which makes our
 123  * life a little less complicated. (We just don't reject any quota
 124  * reservations in that case, when enforcement is off).
 125  * We also return 0 as the values of the timers in Q_GETQUOTA calls, when
 126  * enforcement's off.
 127  * In contrast, warnings are a little different in that they don't
 128  * 'automatically' get started when limits get exceeded.  They do
 129  * get reset to zero, however, when we find the count to be under
 130  * the soft limit (they are only ever set non-zero via userspace).
 131  */
 132 void
 133 xfs_qm_adjust_dqtimers(
 134         xfs_mount_t             *mp,
 135         xfs_disk_dquot_t        *d)
 136 {
 137         ASSERT(d->d_id);
 138
 139 #ifdef DEBUG
 140         if (d->d_blk_hardlimit)
 141                 ASSERT(be64_to_cpu(d->d_blk_softlimit) <=
 142                        be64_to_cpu(d->d_blk_hardlimit));
 143         if (d->d_ino_hardlimit)
 144                 ASSERT(be64_to_cpu(d->d_ino_softlimit) <=
 145                        be64_to_cpu(d->d_ino_hardlimit));
 146         if (d->d_rtb_hardlimit)
 147                 ASSERT(be64_to_cpu(d->d_rtb_softlimit) <=
 148                        be64_to_cpu(d->d_rtb_hardlimit));
 149 #endif
 150
 151         if (!d->d_btimer) {
 152                 if ((d->d_blk_softlimit &&
 153                      (be64_to_cpu(d->d_bcount) >
 154                       be64_to_cpu(d->d_blk_softlimit))) ||
 155                     (d->d_blk_hardlimit &&
 156                      (be64_to_cpu(d->d_bcount) >
 157                       be64_to_cpu(d->d_blk_hardlimit)))) {
 158                         d->d_btimer = cpu_to_be32(get_seconds() +
 159                                         mp->m_quotainfo->qi_btimelimit);
 160                 } else {
 161                         d->d_bwarns = 0;
 162                 }
 163         } else {
 164                 if ((!d->d_blk_softlimit ||
 165                      (be64_to_cpu(d->d_bcount) <=
 166                       be64_to_cpu(d->d_blk_softlimit))) &&
 167                     (!d->d_blk_hardlimit ||
 168                     (be64_to_cpu(d->d_bcount) <=
 169                      be64_to_cpu(d->d_blk_hardlimit)))) {
 170                         d->d_btimer = 0;
 171                 }
 172         }
 173
 174         if (!d->d_itimer) {
 175                 if ((d->d_ino_softlimit &&
 176                      (be64_to_cpu(d->d_icount) >
 177                       be64_to_cpu(d->d_ino_softlimit))) ||
 178                     (d->d_ino_hardlimit &&
 179                      (be64_to_cpu(d->d_icount) >
 180                       be64_to_cpu(d->d_ino_hardlimit)))) {
 181                         d->d_itimer = cpu_to_be32(get_seconds() +
 182                                         mp->m_quotainfo->qi_itimelimit);
 183                 } else {
 184                         d->d_iwarns = 0;
 185                 }
 186         } else {
 187                 if ((!d->d_ino_softlimit ||
 188                      (be64_to_cpu(d->d_icount) <=
 189                       be64_to_cpu(d->d_ino_softlimit)))  &&
 190                     (!d->d_ino_hardlimit ||
 191                      (be64_to_cpu(d->d_icount) <=
 192                       be64_to_cpu(d->d_ino_hardlimit)))) {
 193                         d->d_itimer = 0;
 194                 }
 195         }
 196
 197         if (!d->d_rtbtimer) {
 198                 if ((d->d_rtb_softlimit &&
 199                      (be64_to_cpu(d->d_rtbcount) >
 200                       be64_to_cpu(d->d_rtb_softlimit))) ||
 201                     (d->d_rtb_hardlimit &&
 202                      (be64_to_cpu(d->d_rtbcount) >
 203                       be64_to_cpu(d->d_rtb_hardlimit)))) {
 204                         d->d_rtbtimer = cpu_to_be32(get_seconds() +
 205                                         mp->m_quotainfo->qi_rtbtimelimit);
 206                 } else {
 207                         d->d_rtbwarns = 0;
 208                 }
 209         } else {
 210                 if ((!d->d_rtb_softlimit ||
 211                      (be64_to_cpu(d->d_rtbcount) <=
 212                       be64_to_cpu(d->d_rtb_softlimit))) &&
 213                     (!d->d_rtb_hardlimit ||
 214                      (be64_to_cpu(d->d_rtbcount) <=
 215                       be64_to_cpu(d->d_rtb_hardlimit)))) {
 216                         d->d_rtbtimer = 0;
 217                 }
 218         }
 219 }
 220
 221 /*
 222  * initialize a buffer full of dquots and log the whole thing
 223  */
 224 STATIC void
 225 xfs_qm_init_dquot_blk(
 226         xfs_trans_t     *tp,
 227         xfs_mount_t     *mp,
 228         xfs_dqid_t      id,
 229         uint            type,
 230         xfs_buf_t       *bp)
 231 {
 232         struct xfs_quotainfo    *q = mp->m_quotainfo;
 233         xfs_dqblk_t     *d;
 234         int             curid, i;
 235
 236         ASSERT(tp);
 237         ASSERT(xfs_buf_islocked(bp));
 238
 239         d = bp->b_addr;
 240
 241         /*
 242          * ID of the first dquot in the block - id's are zero based.
 243          */
 244         curid = id - (id % q->qi_dqperchunk);
 245         ASSERT(curid >= 0);
 246         memset(d, 0, BBTOB(q->qi_dqchunklen));
 247         for (i = 0; i < q->qi_dqperchunk; i++, d++, curid++) {
 248                 d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
 249                 d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
 250                 d->dd_diskdq.d_id = cpu_to_be32(curid);
 251                 d->dd_diskdq.d_flags = type;
 252                 if (xfs_sb_version_hascrc(&mp->m_sb)) {
 253                         uuid_copy(&d->dd_uuid, &mp->m_sb.sb_uuid);
 254                         xfs_update_cksum((char *)d, sizeof(struct xfs_dqblk),
 255                                          XFS_DQUOT_CRC_OFF);
 256                 }
 257         }
 258
 259         xfs_trans_dquot_buf(tp, bp,
 260                             (type & XFS_DQ_USER ? XFS_BLF_UDQUOT_BUF :
 261                             ((type & XFS_DQ_PROJ) ? XFS_BLF_PDQUOT_BUF :
 262                              XFS_BLF_GDQUOT_BUF)));
 263         xfs_trans_log_buf(tp, bp, 0, BBTOB(q->qi_dqchunklen) - 1);
 264 }
 265
 266 /*
 267  * Initialize the dynamic speculative preallocation thresholds. The lo/hi
 268  * watermarks correspond to the soft and hard limits by default. If a soft limit
 269  * is not specified, we use 95% of the hard limit.
 270  */
 271 void
 272 xfs_dquot_set_prealloc_limits(struct xfs_dquot *dqp)
 273 {
 274         __uint64_t space;
 275
 276         dqp->q_prealloc_hi_wmark = be64_to_cpu(dqp->q_core.d_blk_hardlimit);
 277         dqp->q_prealloc_lo_wmark = be64_to_cpu(dqp->q_core.d_blk_softlimit);
 278         if (!dqp->q_prealloc_lo_wmark) {
 279                 dqp->q_prealloc_lo_wmark = dqp->q_prealloc_hi_wmark;
 280                 do_div(dqp->q_prealloc_lo_wmark, 100);
 281                 dqp->q_prealloc_lo_wmark *= 95;
 282         }
 283
 284         space = dqp->q_prealloc_hi_wmark;
 285
 286         do_div(space, 100);
 287         dqp->q_low_space[XFS_QLOWSP_1_PCNT] = space;
 288         dqp->q_low_space[XFS_QLOWSP_3_PCNT] = space * 3;
 289         dqp->q_low_space[XFS_QLOWSP_5_PCNT] = space * 5;
 290 }
 291
 292 STATIC bool
 293 xfs_dquot_buf_verify_crc(
 294         struct xfs_mount        *mp,
 295         struct xfs_buf          *bp)
 296 {
 297         struct xfs_dqblk        *d = (struct xfs_dqblk *)bp->b_addr;
 298         int                     ndquots;
 299         int                     i;
 300
 301         if (!xfs_sb_version_hascrc(&mp->m_sb))
 302                 return true;
 303
 304         /*
 305          * if we are in log recovery, the quota subsystem has not been
 306          * initialised so we have no quotainfo structure. In that case, we need
 307          * to manually calculate the number of dquots in the buffer.
 308          */
 309         if (mp->m_quotainfo)
 310                 ndquots = mp->m_quotainfo->qi_dqperchunk;
 311         else
 312                 ndquots = xfs_qm_calc_dquots_per_chunk(mp,
 313                                         XFS_BB_TO_FSB(mp, bp->b_length));
 314
 315         for (i = 0; i < ndquots; i++, d++) {
 316                 if (!xfs_verify_cksum((char *)d, sizeof(struct xfs_dqblk),
 317                                  XFS_DQUOT_CRC_OFF))
 318                         return false;
 319                 if (!uuid_equal(&d->dd_uuid, &mp->m_sb.sb_uuid))
 320                         return false;
 321         }
 322         return true;
 323 }
 324
 325 STATIC bool
 326 xfs_dquot_buf_verify(
 327         struct xfs_mount        *mp,
 328         struct xfs_buf          *bp)
 329 {
 330         struct xfs_dqblk        *d = (struct xfs_dqblk *)bp->b_addr;
 331         xfs_dqid_t              id = 0;
 332         int                     ndquots;
 333         int                     i;
 334
 335         /*
 336          * if we are in log recovery, the quota subsystem has not been
 337          * initialised so we have no quotainfo structure. In that case, we need
 338          * to manually calculate the number of dquots in the buffer.
 339          */
 340         if (mp->m_quotainfo)
 341                 ndquots = mp->m_quotainfo->qi_dqperchunk;
 342         else
 343                 ndquots = xfs_qm_calc_dquots_per_chunk(mp, bp->b_length);
 344
 345         /*
 346          * On the first read of the buffer, verify that each dquot is valid.
 347          * We don't know what the id of the dquot is supposed to be, just that
 348          * they should be increasing monotonically within the buffer. If the
 349          * first id is corrupt, then it will fail on the second dquot in the
 350          * buffer so corruptions could point to the wrong dquot in this case.
 351          */
 352         for (i = 0; i < ndquots; i++) {
 353                 struct xfs_disk_dquot   *ddq;
 354                 int                     error;
 355
 356                 ddq = &d[i].dd_diskdq;
 357
 358                 if (i == 0)
 359                         id = be32_to_cpu(ddq->d_id);
 360
 361                 error = xfs_qm_dqcheck(mp, ddq, id + i, 0, XFS_QMOPT_DOWARN,
 362                                        "xfs_dquot_buf_verify");
 363                 if (error)
 364                         return false;
 365         }
 366         return true;
 367 }
 368
 369 static void
 370 xfs_dquot_buf_read_verify(
 371         struct xfs_buf  *bp)
 372 {
 373         struct xfs_mount        *mp = bp->b_target->bt_mount;
 374
 375         if (!xfs_dquot_buf_verify_crc(mp, bp) || !xfs_dquot_buf_verify(mp, bp)) {
 376                 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
 377                 xfs_buf_ioerror(bp, EFSCORRUPTED);
 378         }
 379 }
 380
 381 /*
 382  * we don't calculate the CRC here as that is done when the dquot is flushed to
 383  * the buffer after the update is done. This ensures that the dquot in the
 384  * buffer always has an up-to-date CRC value.
 385  */
 386 void
 387 xfs_dquot_buf_write_verify(
 388         struct xfs_buf  *bp)
 389 {
 390         struct xfs_mount        *mp = bp->b_target->bt_mount;
 391
 392         if (!xfs_dquot_buf_verify(mp, bp)) {
 393                 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
 394                 xfs_buf_ioerror(bp, EFSCORRUPTED);
 395                 return;
 396         }
 397 }
 398
 399 const struct xfs_buf_ops xfs_dquot_buf_ops = {
 400         .verify_read = xfs_dquot_buf_read_verify,
 401         .verify_write = xfs_dquot_buf_write_verify,
 402 };
 403
 404 /*
 405  * Allocate a block and fill it with dquots.
 406  * This is called when the bmapi finds a hole.
 407  */
 408 STATIC int
 409 xfs_qm_dqalloc(
 410         xfs_trans_t     **tpp,
 411         xfs_mount_t     *mp,
 412         xfs_dquot_t     *dqp,
 413         xfs_inode_t     *quotip,
 414         xfs_fileoff_t   offset_fsb,
 415         xfs_buf_t       **O_bpp)
 416 {
 417         xfs_fsblock_t   firstblock;
 418         xfs_bmap_free_t flist;
 419         xfs_bmbt_irec_t map;
 420         int             nmaps, error, committed;
 421         xfs_buf_t       *bp;
 422         xfs_trans_t     *tp = *tpp;
 423
 424         ASSERT(tp != NULL);
 425
 426         trace_xfs_dqalloc(dqp);
 427
 428         /*
 429          * Initialize the bmap freelist prior to calling bmapi code.
 430          */
 431         xfs_bmap_init(&flist, &firstblock);
 432         xfs_ilock(quotip, XFS_ILOCK_EXCL);
 433         /*
 434          * Return if this type of quotas is turned off while we didn't
 435          * have an inode lock
 436          */
 437         if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
 438                 xfs_iunlock(quotip, XFS_ILOCK_EXCL);
 439                 return (ESRCH);
 440         }
 441
 442         xfs_trans_ijoin(tp, quotip, XFS_ILOCK_EXCL);
 443         nmaps = 1;
 444         error = xfs_bmapi_write(tp, quotip, offset_fsb,
 445                                 XFS_DQUOT_CLUSTER_SIZE_FSB, XFS_BMAPI_METADATA,
 446                                 &firstblock, XFS_QM_DQALLOC_SPACE_RES(mp),
 447                                 &map, &nmaps, &flist);
 448         if (error)
 449                 goto error0;
 450         ASSERT(map.br_blockcount == XFS_DQUOT_CLUSTER_SIZE_FSB);
 451         ASSERT(nmaps == 1);
 452         ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
 453                (map.br_startblock != HOLESTARTBLOCK));
 454
 455         /*
 456          * Keep track of the blkno to save a lookup later
 457          */
 458         dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
 459
 460         /* now we can just get the buffer (there's nothing to read yet) */
 461         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
 462                                dqp->q_blkno,
 463                                mp->m_quotainfo->qi_dqchunklen,
 464                                0);
 465
 466         error = xfs_buf_geterror(bp);
 467         if (error)
 468                 goto error1;
 469         bp->b_ops = &xfs_dquot_buf_ops;
 470
 471         /*
 472          * Make a chunk of dquots out of this buffer and log
 473          * the entire thing.
 474          */
 475         xfs_qm_init_dquot_blk(tp, mp, be32_to_cpu(dqp->q_core.d_id),
 476                               dqp->dq_flags & XFS_DQ_ALLTYPES, bp);
 477
 478         /*
 479          * xfs_bmap_finish() may commit the current transaction and
 480          * start a second transaction if the freelist is not empty.
 481          *
 482          * Since we still want to modify this buffer, we need to
 483          * ensure that the buffer is not released on commit of
 484          * the first transaction and ensure the buffer is added to the
 485          * second transaction.
 486          *
 487          * If there is only one transaction then don't stop the buffer
 488          * from being released when it commits later on.
 489          */
 490
 491         xfs_trans_bhold(tp, bp);
 492
 493         if ((error = xfs_bmap_finish(tpp, &flist, &committed))) {
 494                 goto error1;
 495         }
 496
 497         if (committed) {
 498                 tp = *tpp;
 499                 xfs_trans_bjoin(tp, bp);
 500         } else {
 501                 xfs_trans_bhold_release(tp, bp);
 502         }
 503
 504         *O_bpp = bp;
 505         return 0;
 506
 507       error1:
 508         xfs_bmap_cancel(&flist);
 509       error0:
 510         xfs_iunlock(quotip, XFS_ILOCK_EXCL);
 511
 512         return (error);
 513 }
 514 STATIC int
 515 xfs_qm_dqrepair(
 516         struct xfs_mount        *mp,
 517         struct xfs_trans        *tp,
 518         struct xfs_dquot        *dqp,
 519         xfs_dqid_t              firstid,
 520         struct xfs_buf          **bpp)
 521 {
 522         int                     error;
 523         struct xfs_disk_dquot   *ddq;
 524         struct xfs_dqblk        *d;
 525         int                     i;
 526
 527         /*
 528          * Read the buffer without verification so we get the corrupted
 529          * buffer returned to us. make sure we verify it on write, though.
 530          */
 531         error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, dqp->q_blkno,
 532                                    mp->m_quotainfo->qi_dqchunklen,
 533                                    0, bpp, NULL);
 534
 535         if (error) {
 536                 ASSERT(*bpp == NULL);
 537                 return XFS_ERROR(error);
 538         }
 539         (*bpp)->b_ops = &xfs_dquot_buf_ops;
 540
 541         ASSERT(xfs_buf_islocked(*bpp));
 542         d = (struct xfs_dqblk *)(*bpp)->b_addr;
 543
 544         /* Do the actual repair of dquots in this buffer */
 545         for (i = 0; i < mp->m_quotainfo->qi_dqperchunk; i++) {
 546                 ddq = &d[i].dd_diskdq;
 547                 error = xfs_qm_dqcheck(mp, ddq, firstid + i,
 548                                        dqp->dq_flags & XFS_DQ_ALLTYPES,
 549                                        XFS_QMOPT_DQREPAIR, "xfs_qm_dqrepair");
 550                 if (error) {
 551                         /* repair failed, we're screwed */
 552                         xfs_trans_brelse(tp, *bpp);
 553                         return XFS_ERROR(EIO);
 554                 }
 555         }
 556
 557         return 0;
 558 }
 559
 560 /*
 561  * Maps a dquot to the buffer containing its on-disk version.
 562  * This returns a ptr to the buffer containing the on-disk dquot
 563  * in the bpp param, and a ptr to the on-disk dquot within that buffer
 564  */
 565 STATIC int
 566 xfs_qm_dqtobp(
 567         xfs_trans_t             **tpp,
 568         xfs_dquot_t             *dqp,
 569         xfs_disk_dquot_t        **O_ddpp,
 570         xfs_buf_t               **O_bpp,
 571         uint                    flags)
 572 {
 573         struct xfs_bmbt_irec    map;
 574         int                     nmaps = 1, error;
 575         struct xfs_buf          *bp;
 576         struct xfs_inode        *quotip = xfs_dq_to_quota_inode(dqp);
 577         struct xfs_mount        *mp = dqp->q_mount;
 578         xfs_dqid_t              id = be32_to_cpu(dqp->q_core.d_id);
 579         struct xfs_trans        *tp = (tpp ? *tpp : NULL);
 580
 581         dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;
 582
 583         xfs_ilock(quotip, XFS_ILOCK_SHARED);
 584         if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
 585                 /*
 586                  * Return if this type of quotas is turned off while we
 587                  * didn't have the quota inode lock.
 588                  */
 589                 xfs_iunlock(quotip, XFS_ILOCK_SHARED);
 590                 return ESRCH;
 591         }
 592
 593         /*
 594          * Find the block map; no allocations yet
 595          */
 596         error = xfs_bmapi_read(quotip, dqp->q_fileoffset,
 597                                XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);
 598
 599         xfs_iunlock(quotip, XFS_ILOCK_SHARED);
 600         if (error)
 601                 return error;
 602
 603         ASSERT(nmaps == 1);
 604         ASSERT(map.br_blockcount == 1);
 605
 606         /*
 607          * Offset of dquot in the (fixed sized) dquot chunk.
 608          */
 609         dqp->q_bufoffset = (id % mp->m_quotainfo->qi_dqperchunk) *
 610                 sizeof(xfs_dqblk_t);
 611
 612         ASSERT(map.br_startblock != DELAYSTARTBLOCK);
 613         if (map.br_startblock == HOLESTARTBLOCK) {
 614                 /*
 615                  * We don't allocate unless we're asked to
 616                  */
 617                 if (!(flags & XFS_QMOPT_DQALLOC))
 618                         return ENOENT;
 619
 620                 ASSERT(tp);
 621                 error = xfs_qm_dqalloc(tpp, mp, dqp, quotip,
 622                                         dqp->q_fileoffset, &bp);
 623                 if (error)
 624                         return error;
 625                 tp = *tpp;
 626         } else {
 627                 trace_xfs_dqtobp_read(dqp);
 628
 629                 /*
 630                  * store the blkno etc so that we don't have to do the
 631                  * mapping all the time
 632                  */
 633                 dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
 634
 635                 error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 636                                            dqp->q_blkno,
 637                                            mp->m_quotainfo->qi_dqchunklen,
 638                                            0, &bp, &xfs_dquot_buf_ops);
 639
 640                 if (error == EFSCORRUPTED && (flags & XFS_QMOPT_DQREPAIR)) {
 641                         xfs_dqid_t firstid = (xfs_dqid_t)map.br_startoff *
 642                                                 mp->m_quotainfo->qi_dqperchunk;
 643                         ASSERT(bp == NULL);
 644                         error = xfs_qm_dqrepair(mp, tp, dqp, firstid, &bp);
 645                 }
 646
 647                 if (error) {
 648                         ASSERT(bp == NULL);
 649                         return XFS_ERROR(error);
 650                 }
 651         }
 652
 653         ASSERT(xfs_buf_islocked(bp));
 654         *O_bpp = bp;
 655         *O_ddpp = bp->b_addr + dqp->q_bufoffset;
 656
 657         return (0);
 658 }
 659
 660
 661 /*
 662  * Read in the ondisk dquot using dqtobp() then copy it to an incore version,
 663  * and release the buffer immediately.
 664  *
 665  * If XFS_QMOPT_DQALLOC is set, allocate a dquot on disk if it needed.
 666  */
 667 int
 668 xfs_qm_dqread(
 669         struct xfs_mount        *mp,
 670         xfs_dqid_t              id,
 671         uint                    type,
 672         uint                    flags,
 673         struct xfs_dquot        **O_dqpp)
 674 {
 675         struct xfs_dquot        *dqp;
 676         struct xfs_disk_dquot   *ddqp;
 677         struct xfs_buf          *bp;
 678         struct xfs_trans        *tp = NULL;
 679         int                     error;
 680         int                     cancelflags = 0;
 681
 682
 683         dqp = kmem_zone_zalloc(xfs_qm_dqzone, KM_SLEEP);
 684
 685         dqp->dq_flags = type;
 686         dqp->q_core.d_id = cpu_to_be32(id);
 687         dqp->q_mount = mp;
 688         INIT_LIST_HEAD(&dqp->q_lru);
 689         mutex_init(&dqp->q_qlock);
 690         init_waitqueue_head(&dqp->q_pinwait);
 691
 692         /*
 693          * Because we want to use a counting completion, complete
 694          * the flush completion once to allow a single access to
 695          * the flush completion without blocking.
 696          */
 697         init_completion(&dqp->q_flush);
 698         complete(&dqp->q_flush);
 699
 700         /*
 701          * Make sure group quotas have a different lock class than user
 702          * quotas.
 703          */
 704         if (!(type & XFS_DQ_USER))
 705                 lockdep_set_class(&dqp->q_qlock, &xfs_dquot_other_class);
 706
 707         XFS_STATS_INC(xs_qm_dquot);
 708
 709         trace_xfs_dqread(dqp);
 710
 711         if (flags & XFS_QMOPT_DQALLOC) {
 712                 tp = xfs_trans_alloc(mp, XFS_TRANS_QM_DQALLOC);
 713                 error = xfs_trans_reserve(tp, XFS_QM_DQALLOC_SPACE_RES(mp),
 714                                           XFS_QM_DQALLOC_LOG_RES(mp), 0,
 715                                           XFS_TRANS_PERM_LOG_RES,
 716                                           XFS_WRITE_LOG_COUNT);
 717                 if (error)
 718                         goto error1;
 719                 cancelflags = XFS_TRANS_RELEASE_LOG_RES;
 720         }
 721
 722         /*
 723          * get a pointer to the on-disk dquot and the buffer containing it
 724          * dqp already knows its own type (GROUP/USER).
 725          */
 726         error = xfs_qm_dqtobp(&tp, dqp, &ddqp, &bp, flags);
 727         if (error) {
 728                 /*
 729                  * This can happen if quotas got turned off (ESRCH),
 730                  * or if the dquot didn't exist on disk and we ask to
 731                  * allocate (ENOENT).
 732                  */
 733                 trace_xfs_dqread_fail(dqp);
 734                 cancelflags |= XFS_TRANS_ABORT;
 735                 goto error1;
 736         }
 737
 738         /* copy everything from disk dquot to the incore dquot */
 739         memcpy(&dqp->q_core, ddqp, sizeof(xfs_disk_dquot_t));
 740         xfs_qm_dquot_logitem_init(dqp);
 741
 742         /*
 743          * Reservation counters are defined as reservation plus current usage
 744          * to avoid having to add every time.
 745          */
 746         dqp->q_res_bcount = be64_to_cpu(ddqp->d_bcount);
 747         dqp->q_res_icount = be64_to_cpu(ddqp->d_icount);
 748         dqp->q_res_rtbcount = be64_to_cpu(ddqp->d_rtbcount);
 749
 750         /* initialize the dquot speculative prealloc thresholds */
 751         xfs_dquot_set_prealloc_limits(dqp);
 752
 753         /* Mark the buf so that this will stay incore a little longer */
 754         xfs_buf_set_ref(bp, XFS_DQUOT_REF);
 755
 756         /*
 757          * We got the buffer with a xfs_trans_read_buf() (in dqtobp())
 758          * So we need to release with xfs_trans_brelse().
 759          * The strategy here is identical to that of inodes; we lock
 760          * the dquot in xfs_qm_dqget() before making it accessible to
 761          * others. This is because dquots, like inodes, need a good level of
 762          * concurrency, and we don't want to take locks on the entire buffers
 763          * for dquot accesses.
 764          * Note also that the dquot buffer may even be dirty at this point, if
 765          * this particular dquot was repaired. We still aren't afraid to
 766          * brelse it because we have the changes incore.
 767          */
 768         ASSERT(xfs_buf_islocked(bp));
 769         xfs_trans_brelse(tp, bp);
 770
 771         if (tp) {
 772                 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 773                 if (error)
 774                         goto error0;
 775         }
 776
 777         *O_dqpp = dqp;
 778         return error;
 779
 780 error1:
 781         if (tp)
 782                 xfs_trans_cancel(tp, cancelflags);
 783 error0:
 784         xfs_qm_dqdestroy(dqp);
 785         *O_dqpp = NULL;
 786         return error;
 787 }
 788
 789 /*
 790  * Given the file system, inode OR id, and type (UDQUOT/GDQUOT), return a
 791  * a locked dquot, doing an allocation (if requested) as needed.
 792  * When both an inode and an id are given, the inode's id takes precedence.
 793  * That is, if the id changes while we don't hold the ilock inside this
 794  * function, the new dquot is returned, not necessarily the one requested
 795  * in the id argument.
 796  */
 797 int
 798 xfs_qm_dqget(
 799         xfs_mount_t     *mp,
 800         xfs_inode_t     *ip,      /* locked inode (optional) */
 801         xfs_dqid_t      id,       /* uid/projid/gid depending on type */
 802         uint            type,     /* XFS_DQ_USER/XFS_DQ_PROJ/XFS_DQ_GROUP */
 803         uint            flags,    /* DQALLOC, DQSUSER, DQREPAIR, DOWARN */
 804         xfs_dquot_t     **O_dqpp) /* OUT : locked incore dquot */
 805 {
 806         struct xfs_quotainfo    *qi = mp->m_quotainfo;
 807         struct radix_tree_root *tree = xfs_dquot_tree(qi, type);
 808         struct xfs_dquot        *dqp;
 809         int                     error;
 810
 811         ASSERT(XFS_IS_QUOTA_RUNNING(mp));
 812         if ((! XFS_IS_UQUOTA_ON(mp) && type == XFS_DQ_USER) ||
 813             (! XFS_IS_PQUOTA_ON(mp) && type == XFS_DQ_PROJ) ||
 814             (! XFS_IS_GQUOTA_ON(mp) && type == XFS_DQ_GROUP)) {
 815                 return (ESRCH);
 816         }
 817
 818 #ifdef DEBUG
 819         if (xfs_do_dqerror) {
 820                 if ((xfs_dqerror_target == mp->m_ddev_targp) &&
 821                     (xfs_dqreq_num++ % xfs_dqerror_mod) == 0) {
 822                         xfs_debug(mp, "Returning error in dqget");
 823                         return (EIO);
 824                 }
 825         }
 826
 827         ASSERT(type == XFS_DQ_USER ||
 828                type == XFS_DQ_PROJ ||
 829                type == XFS_DQ_GROUP);
 830         if (ip) {
 831                 ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 832                 ASSERT(xfs_inode_dquot(ip, type) == NULL);
 833         }
 834 #endif
 835
 836 restart:
 837         mutex_lock(&qi->qi_tree_lock);
 838         dqp = radix_tree_lookup(tree, id);
 839         if (dqp) {
 840                 xfs_dqlock(dqp);
 841                 if (dqp->dq_flags & XFS_DQ_FREEING) {
 842                         xfs_dqunlock(dqp);
 843                         mutex_unlock(&qi->qi_tree_lock);
 844                         trace_xfs_dqget_freeing(dqp);
 845                         delay(1);
 846                         goto restart;
 847                 }
 848
 849                 dqp->q_nrefs++;
 850                 mutex_unlock(&qi->qi_tree_lock);
 851
 852                 trace_xfs_dqget_hit(dqp);
 853                 XFS_STATS_INC(xs_qm_dqcachehits);
 854                 *O_dqpp = dqp;
 855                 return 0;
 856         }
 857         mutex_unlock(&qi->qi_tree_lock);
 858         XFS_STATS_INC(xs_qm_dqcachemisses);
 859
 860         /*
 861          * Dquot cache miss. We don't want to keep the inode lock across
 862          * a (potential) disk read. Also we don't want to deal with the lock
 863          * ordering between quotainode and this inode. OTOH, dropping the inode
 864          * lock here means dealing with a chown that can happen before
 865          * we re-acquire the lock.
 866          */
 867         if (ip)
 868                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
 869
 870         error = xfs_qm_dqread(mp, id, type, flags, &dqp);
 871
 872         if (ip)
 873                 xfs_ilock(ip, XFS_ILOCK_EXCL);
 874
 875         if (error)
 876                 return error;
 877
 878         if (ip) {
 879                 /*
 880                  * A dquot could be attached to this inode by now, since
 881                  * we had dropped the ilock.
 882                  */
 883                 if (xfs_this_quota_on(mp, type)) {
 884                         struct xfs_dquot        *dqp1;
 885
 886                         dqp1 = xfs_inode_dquot(ip, type);
 887                         if (dqp1) {
 888                                 xfs_qm_dqdestroy(dqp);
 889                                 dqp = dqp1;
 890                                 xfs_dqlock(dqp);
 891                                 goto dqret;
 892                         }
 893                 } else {
 894                         /* inode stays locked on return */
 895                         xfs_qm_dqdestroy(dqp);
 896                         return XFS_ERROR(ESRCH);
 897                 }
 898         }
 899
 900         mutex_lock(&qi->qi_tree_lock);
 901         error = -radix_tree_insert(tree, id, dqp);
 902         if (unlikely(error)) {
 903                 WARN_ON(error != EEXIST);
 904
 905                 /*
 906                  * Duplicate found. Just throw away the new dquot and start
 907                  * over.
 908                  */
 909                 mutex_unlock(&qi->qi_tree_lock);
 910                 trace_xfs_dqget_dup(dqp);
 911                 xfs_qm_dqdestroy(dqp);
 912                 XFS_STATS_INC(xs_qm_dquot_dups);
 913                 goto restart;
 914         }
 915
 916         /*
 917          * We return a locked dquot to the caller, with a reference taken
 918          */
 919         xfs_dqlock(dqp);
 920         dqp->q_nrefs = 1;
 921
 922         qi->qi_dquots++;
 923         mutex_unlock(&qi->qi_tree_lock);
 924
 925  dqret:
 926         ASSERT((ip == NULL) || xfs_isilocked(ip, XFS_ILOCK_EXCL));
 927         trace_xfs_dqget_miss(dqp);
 928         *O_dqpp = dqp;
 929         return (0);
 930 }
 931
 932
 933 STATIC void
 934 xfs_qm_dqput_final(
 935         struct xfs_dquot        *dqp)
 936 {
 937         struct xfs_quotainfo    *qi = dqp->q_mount->m_quotainfo;
 938         struct xfs_dquot        *gdqp;
 939         struct xfs_dquot        *pdqp;
 940
 941         trace_xfs_dqput_free(dqp);
 942
 943         mutex_lock(&qi->qi_lru_lock);
 944         if (list_empty(&dqp->q_lru)) {
 945                 list_add_tail(&dqp->q_lru, &qi->qi_lru_list);
 946                 qi->qi_lru_count++;
 947                 XFS_STATS_INC(xs_qm_dquot_unused);
 948         }
 949         mutex_unlock(&qi->qi_lru_lock);
 950
 951         /*
 952          * If we just added a udquot to the freelist, then we want to release
 953          * the gdquot/pdquot reference that it (probably) has. Otherwise it'll
 954          * keep the gdquot/pdquot from getting reclaimed.
 955          */
 956         gdqp = dqp->q_gdquot;
 957         if (gdqp) {
 958                 xfs_dqlock(gdqp);
 959                 dqp->q_gdquot = NULL;
 960         }
 961
 962         pdqp = dqp->q_pdquot;
 963         if (pdqp) {
 964                 xfs_dqlock(pdqp);
 965                 dqp->q_pdquot = NULL;
 966         }
 967         xfs_dqunlock(dqp);
 968
 969         /*
 970          * If we had a group/project quota hint, release it now.
 971          */
 972         if (gdqp)
 973                 xfs_qm_dqput(gdqp);
 974         if (pdqp)
 975                 xfs_qm_dqput(pdqp);
 976 }
 977
 978 /*
 979  * Release a reference to the dquot (decrement ref-count) and unlock it.
 980  *
 981  * If there is a group quota attached to this dquot, carefully release that
 982  * too without tripping over deadlocks'n'stuff.
 983  */
 984 void
 985 xfs_qm_dqput(
 986         struct xfs_dquot        *dqp)
 987 {
 988         ASSERT(dqp->q_nrefs > 0);
 989         ASSERT(XFS_DQ_IS_LOCKED(dqp));
 990
 991         trace_xfs_dqput(dqp);
 992
 993         if (--dqp->q_nrefs > 0)
 994                 xfs_dqunlock(dqp);
 995         else
 996                 xfs_qm_dqput_final(dqp);
 997 }
 998
 999 /*
1000  * Release a dquot. Flush it if dirty, then dqput() it.
1001  * dquot must not be locked.
1002  */
1003 void
1004 xfs_qm_dqrele(
1005         xfs_dquot_t     *dqp)
1006 {
1007         if (!dqp)
1008                 return;
1009
1010         trace_xfs_dqrele(dqp);
1011
1012         xfs_dqlock(dqp);
1013         /*
1014          * We don't care to flush it if the dquot is dirty here.
1015          * That will create stutters that we want to avoid.
1016          * Instead we do a delayed write when we try to reclaim
1017          * a dirty dquot. Also xfs_sync will take part of the burden...
1018          */
1019         xfs_qm_dqput(dqp);
1020 }
1021
1022 /*
1023  * This is the dquot flushing I/O completion routine.  It is called
1024  * from interrupt level when the buffer containing the dquot is
1025  * flushed to disk.  It is responsible for removing the dquot logitem
1026  * from the AIL if it has not been re-logged, and unlocking the dquot's
1027  * flush lock. This behavior is very similar to that of inodes..
1028  */
1029 STATIC void
1030 xfs_qm_dqflush_done(
1031         struct xfs_buf          *bp,
1032         struct xfs_log_item     *lip)
1033 {
1034         xfs_dq_logitem_t        *qip = (struct xfs_dq_logitem *)lip;
1035         xfs_dquot_t             *dqp = qip->qli_dquot;
1036         struct xfs_ail          *ailp = lip->li_ailp;
1037
1038         /*
1039          * We only want to pull the item from the AIL if its
1040          * location in the log has not changed since we started the flush.
1041          * Thus, we only bother if the dquot's lsn has
1042          * not changed. First we check the lsn outside the lock
1043          * since it's cheaper, and then we recheck while
1044          * holding the lock before removing the dquot from the AIL.
1045          */
1046         if ((lip->li_flags & XFS_LI_IN_AIL) &&
1047             lip->li_lsn == qip->qli_flush_lsn) {
1048
1049                 /* xfs_trans_ail_delete() drops the AIL lock. */
1050                 spin_lock(&ailp->xa_lock);
1051                 if (lip->li_lsn == qip->qli_flush_lsn)
1052                         xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
1053                 else
1054                         spin_unlock(&ailp->xa_lock);
1055         }
1056
1057         /*
1058          * Release the dq's flush lock since we're done with it.
1059          */
1060         xfs_dqfunlock(dqp);
1061 }
1062
1063 /*
1064  * Write a modified dquot to disk.
1065  * The dquot must be locked and the flush lock too taken by caller.
1066  * The flush lock will not be unlocked until the dquot reaches the disk,
1067  * but the dquot is free to be unlocked and modified by the caller
1068  * in the interim. Dquot is still locked on return. This behavior is
1069  * identical to that of inodes.
1070  */
1071 int
1072 xfs_qm_dqflush(
1073         struct xfs_dquot        *dqp,
1074         struct xfs_buf          **bpp)
1075 {
1076         struct xfs_mount        *mp = dqp->q_mount;
1077         struct xfs_buf          *bp;
1078         struct xfs_disk_dquot   *ddqp;
1079         int                     error;
1080
1081         ASSERT(XFS_DQ_IS_LOCKED(dqp));
1082         ASSERT(!completion_done(&dqp->q_flush));
1083
1084         trace_xfs_dqflush(dqp);
1085
1086         *bpp = NULL;
1087
1088         xfs_qm_dqunpin_wait(dqp);
1089
1090         /*
1091          * This may have been unpinned because the filesystem is shutting
1092          * down forcibly. If that's the case we must not write this dquot
1093          * to disk, because the log record didn't make it to disk.
1094          *
1095          * We also have to remove the log item from the AIL in this case,
1096          * as we wait for an emptry AIL as part of the unmount process.
1097          */
1098         if (XFS_FORCED_SHUTDOWN(mp)) {
1099                 struct xfs_log_item     *lip = &dqp->q_logitem.qli_item;
1100                 dqp->dq_flags &= ~XFS_DQ_DIRTY;
1101
1102                 spin_lock(&mp->m_ail->xa_lock);
1103                 if (lip->li_flags & XFS_LI_IN_AIL)
1104                         xfs_trans_ail_delete(mp->m_ail, lip,
1105                                              SHUTDOWN_CORRUPT_INCORE);
1106                 else
1107                         spin_unlock(&mp->m_ail->xa_lock);
1108                 error = XFS_ERROR(EIO);
1109                 goto out_unlock;
1110         }
1111
1112         /*
1113          * Get the buffer containing the on-disk dquot
1114          */
1115         error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, dqp->q_blkno,
1116                                    mp->m_quotainfo->qi_dqchunklen, 0, &bp, NULL);
1117         if (error)
1118                 goto out_unlock;
1119
1120         /*
1121          * Calculate the location of the dquot inside the buffer.
1122          */
1123         ddqp = bp->b_addr + dqp->q_bufoffset;
1124
1125         /*
1126          * A simple sanity check in case we got a corrupted dquot..
1127          */
1128         error = xfs_qm_dqcheck(mp, &dqp->q_core, be32_to_cpu(ddqp->d_id), 0,
1129                            XFS_QMOPT_DOWARN, "dqflush (incore copy)");
1130         if (error) {
1131                 xfs_buf_relse(bp);
1132                 xfs_dqfunlock(dqp);
1133                 xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
1134                 return XFS_ERROR(EIO);
1135         }
1136
1137         /* This is the only portion of data that needs to persist */
1138         memcpy(ddqp, &dqp->q_core, sizeof(xfs_disk_dquot_t));
1139
1140         /*
1141          * Clear the dirty field and remember the flush lsn for later use.
1142          */
1143         dqp->dq_flags &= ~XFS_DQ_DIRTY;
1144
1145         xfs_trans_ail_copy_lsn(mp->m_ail, &dqp->q_logitem.qli_flush_lsn,
1146                                         &dqp->q_logitem.qli_item.li_lsn);
1147
1148         /*
1149          * copy the lsn into the on-disk dquot now while we have the in memory
1150          * dquot here. This can't be done later in the write verifier as we
1151          * can't get access to the log item at that point in time.
1152          *
1153          * We also calculate the CRC here so that the on-disk dquot in the
1154          * buffer always has a valid CRC. This ensures there is no possibility
1155          * of a dquot without an up-to-date CRC getting to disk.
1156          */
1157         if (xfs_sb_version_hascrc(&mp->m_sb)) {
1158                 struct xfs_dqblk *dqb = (struct xfs_dqblk *)ddqp;
1159
1160                 dqb->dd_lsn = cpu_to_be64(dqp->q_logitem.qli_item.li_lsn);
1161                 xfs_update_cksum((char *)dqb, sizeof(struct xfs_dqblk),
1162                                  XFS_DQUOT_CRC_OFF);
1163         }
1164
1165         /*
1166          * Attach an iodone routine so that we can remove this dquot from the
1167          * AIL and release the flush lock once the dquot is synced to disk.
1168          */
1169         xfs_buf_attach_iodone(bp, xfs_qm_dqflush_done,
1170                                   &dqp->q_logitem.qli_item);
1171
1172         /*
1173          * If the buffer is pinned then push on the log so we won't
1174          * get stuck waiting in the write for too long.
1175          */
1176         if (xfs_buf_ispinned(bp)) {
1177                 trace_xfs_dqflush_force(dqp);
1178                 xfs_log_force(mp, 0);
1179         }
1180
1181         trace_xfs_dqflush_done(dqp);
1182         *bpp = bp;
1183         return 0;
1184
1185 out_unlock:
1186         xfs_dqfunlock(dqp);
1187         return XFS_ERROR(EIO);
1188 }
1189
1190 /*
1191  * Lock two xfs_dquot structures.
1192  *
1193  * To avoid deadlocks we always lock the quota structure with
1194  * the lowerd id first.
1195  */
1196 void
1197 xfs_dqlock2(
1198         xfs_dquot_t     *d1,
1199         xfs_dquot_t     *d2)
1200 {
1201         if (d1 && d2) {
1202                 ASSERT(d1 != d2);
1203                 if (be32_to_cpu(d1->q_core.d_id) >
1204                     be32_to_cpu(d2->q_core.d_id)) {
1205                         mutex_lock(&d2->q_qlock);
1206                         mutex_lock_nested(&d1->q_qlock, XFS_QLOCK_NESTED);
1207                 } else {
1208                         mutex_lock(&d1->q_qlock);
1209                         mutex_lock_nested(&d2->q_qlock, XFS_QLOCK_NESTED);
1210                 }
1211         } else if (d1) {
1212                 mutex_lock(&d1->q_qlock);
1213         } else if (d2) {
1214                 mutex_lock(&d2->q_qlock);
1215         }
1216 }
1217
1218 int __init
1219 xfs_qm_init(void)
1220 {
1221         xfs_qm_dqzone =
1222                 kmem_zone_init(sizeof(struct xfs_dquot), "xfs_dquot");
1223         if (!xfs_qm_dqzone)
1224                 goto out;
1225
1226         xfs_qm_dqtrxzone =
1227                 kmem_zone_init(sizeof(struct xfs_dquot_acct), "xfs_dqtrx");
1228         if (!xfs_qm_dqtrxzone)
1229                 goto out_free_dqzone;
1230
1231         return 0;
1232
1233 out_free_dqzone:
1234         kmem_zone_destroy(xfs_qm_dqzone);
1235 out:
1236         return -ENOMEM;
1237 }
1238
1239 void
1240 xfs_qm_exit(void)
1241 {
1242         kmem_zone_destroy(xfs_qm_dqtrxzone);
1243         kmem_zone_destroy(xfs_qm_dqzone);
1244 }