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>

1 files changed, 18 insertions, 19 deletions

diff --git a/fs/super.c b/fs/super.c
index d4e33e8f1e6f..7ff1349609e4 100644
--- 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);