NFS: Clean up nfs_sb_active/nfs_sb_deactive

Instead of causing umount requests to block on server->active_wq while the
asynchronous sillyrename deletes are executing, we can use the sb->s_active
counter to obtain a reference to the super_block, and then release that
reference in nfs_async_unlink_release().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 8 insertions, 16 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index e9b20173fef3..e527fab40419 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -209,7 +209,6 @@ static int nfs_get_sb(struct file_system_type *, int, const char *, void *, stru
 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
                 int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 static void nfs_kill_super(struct super_block *);
-static void nfs_put_super(struct super_block *);
 static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
 
 static struct file_system_type nfs_fs_type = {
@@ -232,7 +231,6 @@ static const struct super_operations nfs_sops = {
         .alloc_inode    = nfs_alloc_inode,
         .destroy_inode  = nfs_destroy_inode,
         .write_inode    = nfs_write_inode,
-        .put_super      = nfs_put_super,
         .statfs         = nfs_statfs,
         .clear_inode    = nfs_clear_inode,
         .umount_begin   = nfs_umount_begin,
@@ -337,26 +335,20 @@ void __exit unregister_nfs_fs(void)
         unregister_filesystem(&nfs_fs_type);
 }
 
-void nfs_sb_active(struct nfs_server *server)
+void nfs_sb_active(struct super_block *sb)
 {
-        atomic_inc(&server->active);
-}
+        struct nfs_server *server = NFS_SB(sb);
 
-void nfs_sb_deactive(struct nfs_server *server)
-{
-        if (atomic_dec_and_test(&server->active))
-                wake_up(&server->active_wq);
+        if (atomic_inc_return(&server->active) == 1)
+                atomic_inc(&sb->s_active);
 }
 
-static void nfs_put_super(struct super_block *sb)
+void nfs_sb_deactive(struct super_block *sb)
 {
         struct nfs_server *server = NFS_SB(sb);
-        /*
-         * Make sure there are no outstanding ops to this server.
-         * If so, wait for them to finish before allowing the
-         * unmount to continue.
-         */
-        wait_event(server->active_wq, atomic_read(&server->active) == 0);
+
+        if (atomic_dec_and_test(&server->active))
+                deactivate_super(sb);
 }
 
 /*