Merge branch 'master' into next

1 files changed, 22 insertions, 4 deletions

diff --git a/fs/super.c b/fs/super.c
index 645e5403f2a0..6ce501447ada 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -82,7 +82,22 @@ static struct super_block *alloc_super(struct file_system_type *type)
 		 * lock ordering than usbfs:
 		 */
 		lockdep_set_class(&s->s_lock, &type->s_lock_key);
-		down_write(&s->s_umount);
+		/*
+		 * sget() can have s_umount recursion.
+		 *
+		 * When it cannot find a suitable sb, it allocates a new
+		 * one (this one), and tries again to find a suitable old
+		 * one.
+		 *
+		 * In case that succeeds, it will acquire the s_umount
+		 * lock of the old one. Since these are clearly distrinct
+		 * locks, and this object isn't exposed yet, there's no
+		 * risk of deadlocks.
+		 *
+		 * Annotate this by putting this lock in a different
+		 * subclass.
+		 */
+		down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING);
 		s->s_count = S_BIAS;
 		atomic_set(&s->s_active, 1);
 		mutex_init(&s->s_vfs_rename_mutex);
@@ -301,7 +316,7 @@ void generic_shutdown_super(struct super_block *sb)
 		/*
 		 * wait for asynchronous fs operations to finish before going further
 		 */
-		async_synchronize_full_special(&sb->s_async_list);
+		async_synchronize_full_domain(&sb->s_async_list);
 
 		/* bad name - it should be evict_inodes() */
 		invalidate_inodes(sb);
@@ -356,8 +371,10 @@ retry:
 				continue;
 			if (!grab_super(old))
 				goto retry;
-			if (s)
+			if (s) {
+				up_write(&s->s_umount);
 				destroy_super(s);
+			}
 			return old;
 		}
 	}
@@ -372,6 +389,7 @@ retry:
 	err = set(s, data);
 	if (err) {
 		spin_unlock(&sb_lock);
+		up_write(&s->s_umount);
 		destroy_super(s);
 		return ERR_PTR(err);
 	}
@@ -470,7 +488,7 @@ restart:
 		sb->s_count++;
 		spin_unlock(&sb_lock);
 		down_read(&sb->s_umount);
-		async_synchronize_full_special(&sb->s_async_list);
+		async_synchronize_full_domain(&sb->s_async_list);
 		if (sb->s_root && (wait || sb->s_dirt))
 			sb->s_op->sync_fs(sb, wait);
 		up_read(&sb->s_umount);