FS-Cache: Make cookie relinquishment wait for outstanding reads

Make fscache_relinquish_cookie() log a warning and wait if there are any
outstanding reads left on the cookie it was given.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c
index 30afdfa7aec7..c857ab824d6e 100644
--- a/fs/fscache/operation.c
+++ b/fs/fscache/operation.c
@@ -340,8 +340,14 @@ void fscache_put_operation(struct fscache_operation *op)
 
         object = op->object;
 
-        if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags))
-                atomic_dec(&object->n_reads);
+        if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags)) {
+                if (atomic_dec_and_test(&object->n_reads)) {
+                        clear_bit(FSCACHE_COOKIE_WAITING_ON_READS,
+                                  &object->cookie->flags);
+                        wake_up_bit(&object->cookie->flags,
+                                    FSCACHE_COOKIE_WAITING_ON_READS);
+                }
+        }
 
         /* now... we may get called with the object spinlock held, so we
          * complete the cleanup here only if we can immediately acquire the