fs: unlock the superblock during iterate_supers_type

This function takes super_lock in shared mode, so it should release the
same lock.

Cc: [email protected] # v6.16-rc1
Fixes: af7551c ("super: remove pointless s_root checks")
Signed-off-by: "Darrick J. Wong" <[email protected]>
Link: https://lore.kernel.org/20250611164044.GF6138@frogsfrogsfrogs
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

Author: Darrick J. Wong

fs/super.c

@@ -964,8 +964,10 @@ void iterate_supers_type(struct file_system_type *type,
 		spin_unlock(&sb_lock);
 
 		locked = super_lock_shared(sb);
-		if (locked)
+		if (locked) {
 			f(sb, arg);
+			super_unlock_shared(sb);
+		}
 
 		spin_lock(&sb_lock);
 		if (p)