1 files changed, 18 insertions, 3 deletions

diff --git a/fs/super.c b/fs/super.c
index 645e5403f2a0..8349ed6b1412 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);
@@ -470,7 +485,7 @@ 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);