Btrfs: fix inode cache waiters hanging on path allocation failure

If the caching thread fails to allocate a path, it returns without waking
up any cache waiters, leaving them hang forever. Fix this by following the
same approach as when we fail to start the caching thread: print an error
message, disable inode caching and make the wakers fallback to non-caching
mode behaviour (calling btrfs_find_free_objectid()).

Fixes: 581bb050941b4f ("Btrfs: Cache free inode numbers in memory")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index c242ae434355..c692c8b6e371 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -42,8 +42,10 @@ static int caching_kthread(void *data)
                 return 0;
 
         path = btrfs_alloc_path();
-        if (!path)
+        if (!path) {
+                fail_caching_thread(root);
                 return -ENOMEM;
+        }
 
         /* Since the commit root is read-only, we can safely skip locking. */
         path->skip_locking = 1;