btrfs: kill magical embedded struct superblock

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
(cherry picked from commit 0ee5dc676a5f8fadede608c7281dfedb1ae714ea)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 8b99c79ad1a7312331fde119768aade07459997b..a4612ce2878d8315dc899e09edac5307759804d3 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1224,7 +1224,7 @@ struct btrfs_root {
         * right now this just gets used so that a root has its own devid
         * for stat.  It may be used for more later
         */
-       struct super_block anon_super;
+       dev_t anon_dev;
 };
 
 struct btrfs_ioctl_defrag_range_args {

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 94ecac33cf2d924ab55cff813b774c04acd285a9..07b3ac662e193e6b3a19180c3c3c9bfccbeb8028 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1111,12 +1111,7 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
        init_completion(&root->kobj_unregister);
        root->defrag_running = 0;
        root->root_key.objectid = objectid;
-       root->anon_super.s_root = NULL;
-       root->anon_super.s_dev = 0;
-       INIT_LIST_HEAD(&root->anon_super.s_list);
-       INIT_LIST_HEAD(&root->anon_super.s_instances);
-       init_rwsem(&root->anon_super.s_umount);
-
+       root->anon_dev = 0;
        return 0;
 }
 
@@ -1345,7 +1340,7 @@ again:
        spin_lock_init(&root->cache_lock);
        init_waitqueue_head(&root->cache_wait);
 
-       ret = set_anon_super(&root->anon_super, NULL);
+       ret = get_anon_bdev(&root->anon_dev);
        if (ret)
                goto fail;
 
@@ -2432,10 +2427,8 @@ static void free_fs_root(struct btrfs_root *root)
 {
        iput(root->cache_inode);
        WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
-       if (root->anon_super.s_dev) {
-               down_write(&root->anon_super.s_umount);
-               kill_anon_super(&root->anon_super);
-       }
+       if (root->anon_dev)
+               free_anon_bdev(root->anon_dev);
        free_extent_buffer(root->node);
        free_extent_buffer(root->commit_root);
        kfree(root->free_ino_ctl);

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ba951764b0054f5fa123c5ac13dc1539aa293e10..fdd9e907f4ccede56453a438d3fff339149460f3 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6883,7 +6883,7 @@ static int btrfs_getattr(struct vfsmount *mnt,
 {
        struct inode *inode = dentry->d_inode;
        generic_fillattr(inode, stat);
-       stat->dev = BTRFS_I(inode)->root->anon_super.s_dev;
+       stat->dev = BTRFS_I(inode)->root->anon_dev;
        stat->blksize = PAGE_CACHE_SIZE;
        stat->blocks = (inode_get_bytes(inode) +
                        BTRFS_I(inode)->delalloc_bytes) >> 9;

diff --git a/fs/super.c b/fs/super.c
index ab3d672db0deae0a84a01bc1938cd967cc27e79f..61a1e47f1049d46ea58930dfbfb20864c0f5cd5b 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -657,7 +657,7 @@ 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;
@@ -684,24 +684,38 @@ 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);
 

diff --git a/include/linux/fs.h b/include/linux/fs.h
index b5b979247863718f10da2764b3eab280a3005e9f..73a8d1f46b3b4c30d100978b03dbff85badb2014 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1837,6 +1837,8 @@ void kill_litter_super(struct super_block *sb);
 void deactivate_super(struct super_block *sb);
 void deactivate_locked_super(struct super_block *sb);
 int set_anon_super(struct super_block *s, void *data);
+int get_anon_bdev(dev_t *);
+void free_anon_bdev(dev_t);
 struct super_block *sget(struct file_system_type *type,
                        int (*test)(struct super_block *,void *),
                        int (*set)(struct super_block *,void *),