btrfs: kill magical embedded struct superblock

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

1 files changed, 23 insertions, 9 deletions

diff --git a/fs/super.c b/fs/super.c
index 444da9579068..263edeb9f0e9 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -693,7 +693,7 @@ static DEFINE_IDA(unnamed_dev_ida);
 static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
 static int unnamed_dev_start = 0; /* don't bother trying below it */
 
-int set_anon_super(struct super_block *s, void *data)
+int get_anon_bdev(dev_t *p)
 {
         int dev;
         int error;
@@ -720,24 +720,38 @@ int set_anon_super(struct super_block *s, void *data)
                 spin_unlock(&unnamed_dev_lock);
                 return -EMFILE;
         }
-        s->s_dev = MKDEV(0, dev & MINORMASK);
-        s->s_bdi = &noop_backing_dev_info;
+        *p = MKDEV(0, dev & MINORMASK);
         return 0;
 }
+EXPORT_SYMBOL(get_anon_bdev);
 
-EXPORT_SYMBOL(set_anon_super);
-
-void kill_anon_super(struct super_block *sb)
+void free_anon_bdev(dev_t dev)
 {
-        int slot = MINOR(sb->s_dev);
-
-        generic_shutdown_super(sb);
+        int slot = MINOR(dev);
         spin_lock(&unnamed_dev_lock);
         ida_remove(&unnamed_dev_ida, slot);
         if (slot < unnamed_dev_start)
                 unnamed_dev_start = slot;
         spin_unlock(&unnamed_dev_lock);
 }
+EXPORT_SYMBOL(free_anon_bdev);
+
+int set_anon_super(struct super_block *s, void *data)
+{
+        int error = get_anon_bdev(&s->s_dev);
+        if (!error)
+                s->s_bdi = &noop_backing_dev_info;
+        return error;
+}
+
+EXPORT_SYMBOL(set_anon_super);
+
+void kill_anon_super(struct super_block *sb)
+{
+        dev_t dev = sb->s_dev;
+        generic_shutdown_super(sb);
+        free_anon_bdev(dev);
+}
 
 EXPORT_SYMBOL(kill_anon_super);