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: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index c226656..cf283b0 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2046,11 +2046,12 @@
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);