alloc_super(): do ->s_umount initialization earlier

... so that failure exits could count on it having been
done.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/super.c b/fs/super.c
index d4e33e8f1e6fee3172e0e07e9d358587eea34bc4..7ff1349609e4874a35268876065490d77f5e01ab 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -191,6 +191,24 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
 
        INIT_LIST_HEAD(&s->s_mounts);
        s->s_user_ns = get_user_ns(user_ns);
+       init_rwsem(&s->s_umount);
+       lockdep_set_class(&s->s_umount, &type->s_umount_key);
+       /*
+        * 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);
 
        if (security_sb_alloc(s))
                goto fail;
@@ -218,25 +236,6 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
                goto fail;
        if (list_lru_init_memcg(&s->s_inode_lru))
                goto fail;
-
-       init_rwsem(&s->s_umount);
-       lockdep_set_class(&s->s_umount, &type->s_umount_key);
-       /*
-        * 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 = 1;
        atomic_set(&s->s_active, 1);
        mutex_init(&s->s_vfs_rename_mutex);