[PATCH 4/5] Btrfs: fix inode cache waiters hanging on path allocation failure

[fdmanana@kernel.org]

From: Filipe Manana <fdmanana@suse.com>

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")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/inode-map.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index 05b8c9927f29..4820e05ea6bd 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -41,8 +41,10 @@ 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;
-- 
2.11.0