Btrfs: fix deadlock in run_delalloc_nocow

[ Upstream commit e89166990f11c3f21e1649d760dd35f9e410321c ]

@cur_offset is not set back to what it should be (@cow_start) if
btrfs_next_leaf() returns something wrong, and the range [cow_start,
cur_offset) remains locked forever.

cc: <stable@vger.kernel.org>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1423231c7e4930b5b0859bff705aed4613f616bc..884e90e9622a179e5c4465592cee910af10b0e14 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1282,8 +1282,11 @@ next_slot:
                leaf = path->nodes[0];
                if (path->slots[0] >= btrfs_header_nritems(leaf)) {
                        ret = btrfs_next_leaf(root, path);
-                       if (ret < 0)
+                       if (ret < 0) {
+                               if (cow_start != (u64)-1)
+                                       cur_offset = cow_start;
                                goto error;
+                       }
                        if (ret > 0)
                                break;
                        leaf = path->nodes[0];