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Commit 85dc4aac authored by Josef Bacik's avatar Josef Bacik Committed by Greg Kroah-Hartman
Browse files

btrfs: check the root node for uptodate before returning it 



commit 120de408e4b97504a2d9b5ca534b383de2c73d49 upstream.

Now that we clear the extent buffer uptodate if we fail to write it out
we need to check to see if our root node is uptodate before we search
down it.  Otherwise we could return stale data (or potentially corrupt
data that was caught by the write verification step) and think that the
path is OK to search down.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent eeec77bb

fs/btrfs/ctree.c

+15 −4
Original line number Diff line number Diff line
@@ -2658,12 +2658,9 @@ static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root, 
{

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct extent_buffer *b;

	int root_lock;

	int root_lock = 0;

	int level = 0;



	/* We try very hard to do read locks on the root */

	root_lock = BTRFS_READ_LOCK;



	if (p->search_commit_root) {

		/*

		 * The commit roots are read only so we always do read locks,
@@ -2701,6 +2698,9 @@ static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root, 
		goto out;

	}



	/* We try very hard to do read locks on the root */

	root_lock = BTRFS_READ_LOCK;



	/*

	 * If the level is set to maximum, we can skip trying to get the read

	 * lock.
@@ -2727,6 +2727,17 @@ static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root, 
	level = btrfs_header_level(b);



out:

	/*

	 * The root may have failed to write out at some point, and thus is no

	 * longer valid, return an error in this case.

	 */

	if (!extent_buffer_uptodate(b)) {

		if (root_lock)

			btrfs_tree_unlock_rw(b, root_lock);

		free_extent_buffer(b);

		return ERR_PTR(-EIO);

	}



	p->nodes[level] = b;

	if (!p->skip_locking)

		p->locks[level] = root_lock;