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| author | Chris Mason <clm@fb.com> | 2015-10-13 14:06:48 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-10-27 09:45:56 +0900 |
| commit | 997badf1e03dfd39854094f7767e1a4cf5ed310b (patch) | |
| tree | 82937b81b859d0fe6352311fb5386243731f087e | |
| parent | 3408c1b1193ec14c555e21a41b452c1ed012ccec (diff) | |
| download | lwn-997badf1e03dfd39854094f7767e1a4cf5ed310b.tar.gz lwn-997badf1e03dfd39854094f7767e1a4cf5ed310b.zip | |
btrfs: fix use after free iterating extrefs
commit dc6c5fb3b514221f2e9d21ee626a9d95d3418dff upstream.
The code for btrfs inode-resolve has never worked properly for
files with enough hard links to trigger extrefs. It was trying to
get the leaf out of a path after freeing the path:
btrfs_release_path(path);
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, slot);
The fix here is to use the extent buffer we cloned just a little higher
up to avoid deadlocks caused by using the leaf in the path.
Signed-off-by: Chris Mason <clm@fb.com>
cc: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/btrfs/backref.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 6244f9cf8ae3..0529defbdf73 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1692,7 +1692,6 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, int found = 0; struct extent_buffer *eb; struct btrfs_inode_extref *extref; - struct extent_buffer *leaf; u32 item_size; u32 cur_offset; unsigned long ptr; @@ -1720,9 +1719,8 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); btrfs_release_path(path); - leaf = path->nodes[0]; - item_size = btrfs_item_size_nr(leaf, slot); - ptr = btrfs_item_ptr_offset(leaf, slot); + item_size = btrfs_item_size_nr(eb, slot); + ptr = btrfs_item_ptr_offset(eb, slot); cur_offset = 0; while (cur_offset < item_size) { @@ -1736,7 +1734,7 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, if (ret) break; - cur_offset += btrfs_inode_extref_name_len(leaf, extref); + cur_offset += btrfs_inode_extref_name_len(eb, extref); cur_offset += sizeof(*extref); } btrfs_tree_read_unlock_blocking(eb); |