FS-Cache: Check that there are no read ops when cookie relinquished

Check that the netfs isn't trying to relinquish a cookie that still has read
operations in progress upon it.  If there are, then give log a warning and BUG.

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

1 files changed, 8 insertions, 0 deletions

diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 990535071a8a..0666996adf80 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -452,6 +452,14 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
 
                 _debug("RELEASE OBJ%x", object->debug_id);
 
+                if (atomic_read(&object->n_reads)) {
+                        spin_unlock(&cookie->lock);
+                        printk(KERN_ERR "FS-Cache:"
+                               " Cookie '%s' still has %d outstanding reads\n",
+                               cookie->def->name, atomic_read(&object->n_reads));
+                        BUG();
+                }
+
                 /* detach each cache object from the object cookie */
                 spin_lock(&object->lock);
                 hlist_del_init(&object->cookie_link);