diff options
| author |   Jan Schmidt <list.btrfs@jan-o-sch.net> | 2013-04-13 13:19:55 +0000 |
|---|---|---|
| committer |   Josef Bacik <jbacik@fusionio.com> | 2013-05-06 15:54:48 -0400 |
| commit | 47fb091fb787420cd195e66f162737401cce023f (patch) | |
| tree | 0214d77b462613aa605d3107633bec7445d53d57 /fs/btrfs/ctree.c | |
| parent | Btrfs: fix accessing the root pointer in tree mod log functions (diff) | |
| download | linux-dev-47fb091fb787420cd195e66f162737401cce023f.tar.xz linux-dev-47fb091fb787420cd195e66f162737401cce023f.zip | |
Btrfs: fix unlock after free on rewinded tree blocks
When tree_mod_log_rewind decides to make a copy of the current tree buffer
for its modifications, it subsequently freed the buffer before unlocking it.
Obviously, those operations are required in reverse order.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Diffstat (limited to 'fs/btrfs/ctree.c')
| -rw-r--r-- | fs/btrfs/ctree.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index d7e0576038fb..c3c3d37f9c58 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1191,6 +1191,13 @@ __tree_mod_log_rewind(struct extent_buffer *eb, u64 time_seq, btrfs_set_header_nritems(eb, n); } +/* + * Called with eb read locked. If the buffer cannot be rewinded, the same buffer + * is returned. If rewind operations happen, a fresh buffer is returned. The + * returned buffer is always read-locked. If the returned buffer is not the + * input buffer, the lock on the input buffer is released and the input buffer + * is freed (its refcount is decremented). + */ static struct extent_buffer * tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb, u64 time_seq) @@ -1224,8 +1231,11 @@ tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb, } extent_buffer_get(eb_rewin); + btrfs_tree_read_unlock(eb); free_extent_buffer(eb); + extent_buffer_get(eb_rewin); + btrfs_tree_read_lock(eb_rewin); __tree_mod_log_rewind(eb_rewin, time_seq, tm); WARN_ON(btrfs_header_nritems(eb_rewin) > BTRFS_NODEPTRS_PER_BLOCK(fs_info->tree_root)); @@ -2794,15 +2804,9 @@ again: btrfs_clear_path_blocking(p, b, BTRFS_READ_LOCK); } + b = tree_mod_log_rewind(root->fs_info, b, time_seq); p->locks[level] = BTRFS_READ_LOCK; p->nodes[level] = b; - b = tree_mod_log_rewind(root->fs_info, b, time_seq); - if (b != p->nodes[level]) { - btrfs_tree_unlock_rw(p->nodes[level], - p->locks[level]); - p->locks[level] = 0; - p->nodes[level] = b; - } } else { p->slots[level] = slot; unlock_up(p, level, lowest_unlock, 0, NULL); |