Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux...

[linux-imx.git] / fs / btrfs / inode.c

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6d1b93c8aafb8a4d7b832cab8585ebf1ac1ced42..021694c081814828272ff03a8b9e1f64732a46cc 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2166,16 +2166,23 @@ static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
                if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
                        continue;
 
-               extent_offset = btrfs_file_extent_offset(leaf, extent);
-               if (key.offset - extent_offset != offset)
+               /*
+                * 'offset' refers to the exact key.offset,
+                * NOT the 'offset' field in btrfs_extent_data_ref, ie.
+                * (key.offset - extent_offset).
+                */
+               if (key.offset != offset)
                        continue;
 
+               extent_offset = btrfs_file_extent_offset(leaf, extent);
                num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
+
                if (extent_offset >= old->extent_offset + old->offset +
                    old->len || extent_offset + num_bytes <=
                    old->extent_offset + old->offset)
                        continue;
 
+               ret = 0;
                break;
        }
 
@@ -2187,7 +2194,7 @@ static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
 
        backref->root_id = root_id;
        backref->inum = inum;
-       backref->file_pos = offset + extent_offset;
+       backref->file_pos = offset;
        backref->num_bytes = num_bytes;
        backref->extent_offset = extent_offset;
        backref->generation = btrfs_file_extent_generation(leaf, extent);
@@ -2210,7 +2217,8 @@ static noinline bool record_extent_backrefs(struct btrfs_path *path,
        new->path = path;
 
        list_for_each_entry_safe(old, tmp, &new->head, list) {
-               ret = iterate_inodes_from_logical(old->bytenr, fs_info,
+               ret = iterate_inodes_from_logical(old->bytenr +
+                                                 old->extent_offset, fs_info,
                                                  path, record_one_backref,
                                                  old);
                BUG_ON(ret < 0 && ret != -ENOENT);
@@ -4391,9 +4399,6 @@ static int btrfs_setsize(struct inode *inode, struct iattr *attr)
        int mask = attr->ia_valid;
        int ret;
 
-       if (newsize == oldsize)
-               return 0;
-
        /*
         * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
         * special case where we need to update the times despite not having
@@ -5165,14 +5170,31 @@ next:
        }
 
        /* Reached end of directory/root. Bump pos past the last item. */
-       if (key_type == BTRFS_DIR_INDEX_KEY)
-               /*
-                * 32-bit glibc will use getdents64, but then strtol -
-                * so the last number we can serve is this.
-                */
-               ctx->pos = 0x7fffffff;
-       else
-               ctx->pos++;
+       ctx->pos++;
+
+       /*
+        * Stop new entries from being returned after we return the last
+        * entry.
+        *
+        * New directory entries are assigned a strictly increasing
+        * offset.  This means that new entries created during readdir
+        * are *guaranteed* to be seen in the future by that readdir.
+        * This has broken buggy programs which operate on names as
+        * they're returned by readdir.  Until we re-use freed offsets
+        * we have this hack to stop new entries from being returned
+        * under the assumption that they'll never reach this huge
+        * offset.
+        *
+        * This is being careful not to overflow 32bit loff_t unless the
+        * last entry requires it because doing so has broken 32bit apps
+        * in the past.
+        */
+       if (key_type == BTRFS_DIR_INDEX_KEY) {
+               if (ctx->pos >= INT_MAX)
+                       ctx->pos = LLONG_MAX;
+               else
+                       ctx->pos = INT_MAX;
+       }
 nopos:
        ret = 0;
 err: