ceph: unregister bdi before kill_anon_super releases device name

Unregister and destroy the bdi in put_super, after mount is r/o, but before
put_anon_super releases the device name.

For symmetry, bdi_destroy in destroy_client (we bdi_init in create_client).

Only set s_bdi if bdi_register succeeds, since we use it to decide whether
to bdi_unregister.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 16 insertions, 7 deletions

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index f888cf487b7c..110857ba9269 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -47,10 +47,20 @@ const char *ceph_file_part(const char *s, int len)
  */
 static void ceph_put_super(struct super_block *s)
 {
-        struct ceph_client *cl = ceph_client(s);
+        struct ceph_client *client = ceph_sb_to_client(s);
 
         dout("put_super\n");
-        ceph_mdsc_close_sessions(&cl->mdsc);
+        ceph_mdsc_close_sessions(&client->mdsc);
+
+        /*
+         * ensure we release the bdi before put_anon_super releases
+         * the device name.
+         */
+        if (s->s_bdi == &client->backing_dev_info) {
+                bdi_unregister(&client->backing_dev_info);
+                s->s_bdi = NULL;
+        }
+
         return;
 }
 
@@ -636,6 +646,8 @@ static void ceph_destroy_client(struct ceph_client *client)
         destroy_workqueue(client->pg_inv_wq);
         destroy_workqueue(client->trunc_wq);
 
+        bdi_destroy(&client->backing_dev_info);
+
         if (client->msgr)
                 ceph_messenger_destroy(client->msgr);
         mempool_destroy(client->wb_pagevec_pool);
@@ -876,14 +888,14 @@ static int ceph_register_bdi(struct super_block *sb, struct ceph_client *client)
 {
         int err;
 
-        sb->s_bdi = &client->backing_dev_info;
-
         /* set ra_pages based on rsize mount option? */
         if (client->mount_args->rsize >= PAGE_CACHE_SIZE)
                 client->backing_dev_info.ra_pages =
                         (client->mount_args->rsize + PAGE_CACHE_SIZE - 1)
                         >> PAGE_SHIFT;
         err = bdi_register_dev(&client->backing_dev_info, sb->s_dev);
+        if (!err)
+                sb->s_bdi = &client->backing_dev_info;
         return err;
 }
 
@@ -957,9 +969,6 @@ static void ceph_kill_sb(struct super_block *s)
         dout("kill_sb %p\n", s);
         ceph_mdsc_pre_umount(&client->mdsc);
         kill_anon_super(s);    /* will call put_super after sb is r/o */
-        if (s->s_bdi == &client->backing_dev_info)
-                bdi_unregister(&client->backing_dev_info);
-        bdi_destroy(&client->backing_dev_info);
         ceph_destroy_client(client);
 }