[v2,2/7] btrfs-progs: Fix one-byte overlap bug in free_block_group_cache
diff mbox

Message ID 20170911063612.32114-3-quwenruo.btrfs@gmx.com
State New
Headers show

Commit Message

Qu Wenruo Sept. 11, 2017, 6:36 a.m. UTC
free_block_group_cache() calls clear_extent_bits() with wrong end, which
is one byte larger than the correct range.

This will cause the next adjacent cache state be split.
And due to the split, private pointer (which points to block group
cache) will be reset to NULL.

This is very hard to detect as this function only gets called in
cleanup_temp_chunks() which is just before mkfs finishes.
This bug only get exposed when reworking --rootdir option.

Signed-off-by: Qu Wenruo <quwenruo.btrfs@gmx.com>
---
 extent-tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch
diff mbox

diff --git a/extent-tree.c b/extent-tree.c
index eed56886..525a237e 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -3724,7 +3724,7 @@  static int free_block_group_cache(struct btrfs_trans_handle *trans,
 		btrfs_remove_free_space_cache(cache);
 		kfree(cache->free_space_ctl);
 	}
-	clear_extent_bits(&fs_info->block_group_cache, bytenr, bytenr + len,
+	clear_extent_bits(&fs_info->block_group_cache, bytenr, bytenr + len - 1,
 			  (unsigned int)-1);
 	ret = free_space_info(fs_info, flags, len, 0, NULL);
 	if (ret < 0)