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Commit ecbe2402 authored by Chris Mason's avatar Chris Mason
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Btrfs: Keep fs_mutex during reads done by snapshot deletion 



There was an optimization to drop the fs_mutex when doing snapshot deletion
reads, but this can lead to false positives on checksumming errors.  Keep
the lock for now.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 140dfd00

fs/btrfs/extent-tree.c

+4 −3
Original line number Diff line number Diff line
@@ -2046,11 +2046,12 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans, 
		if (!next || !btrfs_buffer_uptodate(next)) {

			free_extent_buffer(next);

			reada_walk_down(root, cur, path->slots[*level]);

			mutex_unlock(&root->fs_info->fs_mutex);

			next = read_tree_block(root, bytenr, blocksize);

			mutex_lock(&root->fs_info->fs_mutex);



			/* we dropped the lock, check one more time */

			/* we used to drop the lock above, keep the

			 * code to double check so that we won't forget

			 * when we drop the lock again in the future

			 */

			ret = lookup_extent_ref(trans, root, bytenr,

						blocksize, &refs);

			BUG_ON(ret);