FS-Cache: Increase reference of parent after registering, netfs success

If netfs exist, fscache should not increase the reference of parent's
usage and n_children, otherwise, never be decreased.

v2: thanks David's suggest,
 move increasing reference of parent if success
 use kmem_cache_free() freeing primary_index directly

v3: don't move "netfs->primary_index->parent = &fscache_fsdef_index;"

Cc: stable@vger.kernel.org # v2.6.30+
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 5 deletions

diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index 6d941f56faf4..458cc968d9a0 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -47,9 +47,6 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
         netfs->primary_index->netfs_data        = netfs;
         netfs->primary_index->flags             = 1 << FSCACHE_COOKIE_ENABLED;
 
-        atomic_inc(&netfs->primary_index->parent->usage);
-        atomic_inc(&netfs->primary_index->parent->n_children);
-
         spin_lock_init(&netfs->primary_index->lock);
         INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);
 
@@ -62,6 +59,9 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
                         goto already_registered;
         }
 
+        atomic_inc(&netfs->primary_index->parent->usage);
+        atomic_inc(&netfs->primary_index->parent->n_children);
+
         list_add(&netfs->link, &fscache_netfs_list);
         ret = 0;
 
@@ -71,8 +71,7 @@ already_registered:
         up_write(&fscache_addremove_sem);
 
         if (ret < 0) {
-                netfs->primary_index->parent = NULL;
-                __fscache_cookie_put(netfs->primary_index);
+                kmem_cache_free(fscache_cookie_jar, netfs->primary_index);
                 netfs->primary_index = NULL;
         }