4.19-stable review patch. If anyone has any objections, please let me know.
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From: David Sterba dsterba@suse.com
[ Upstream commit 6fbc6f4ac1f4907da4fc674251527e7dc79ffbf6 ]
The may_destroy_subvol() looks up a root by a key, allowing to do an inexact search when key->offset is -1. It's never expected to find such item, as it would break the allowed range of a root id.
Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/inode.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 7f675862ffb0e..15ebebed40056 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4296,7 +4296,14 @@ static noinline int may_destroy_subvol(struct btrfs_root *root) ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0); if (ret < 0) goto out; - BUG_ON(ret == 0); + if (ret == 0) { + /* + * Key with offset -1 found, there would have to exist a root + * with such id, but this is out of valid range. + */ + ret = -EUCLEAN; + goto out; + }
ret = 0; if (path->slots[0] > 0) {