logfs: fix a leak in get_sb

a) switch ->put_device() to logfs_super *
b) actually call it on early failures in logfs_get_sb_device()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/logfs/dev_bdev.c

@@ -298,9 +298,9 @@ static int bdev_write_sb(struct super_block *sb, struct page *page)
 	return sync_request(page, bdev, WRITE);
 }
 
-static void bdev_put_device(struct super_block *sb)
+static void bdev_put_device(struct logfs_super *s)
 {
-	close_bdev_exclusive(logfs_super(sb)->s_bdev, FMODE_READ|FMODE_WRITE);
+	close_bdev_exclusive(s->s_bdev, FMODE_READ|FMODE_WRITE);
 }
 
 static int bdev_can_write_buf(struct super_block *sb, u64 ofs)

fs/logfs/dev_mtd.c

@@ -230,9 +230,9 @@ static void mtd_writeseg(struct super_block *sb, u64 ofs, size_t len)
 	__mtd_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT);
 }
 
-static void mtd_put_device(struct super_block *sb)
+static void mtd_put_device(struct logfs_super *s)
 {
-	put_mtd_device(logfs_super(sb)->s_mtd);
+	put_mtd_device(s->s_mtd);
 }
 
 static int mtd_can_write_buf(struct super_block *sb, u64 ofs)

fs/logfs/logfs.h

@@ -136,6 +136,7 @@ struct logfs_area_ops {
 	int	(*erase_segment)(struct logfs_area *area);
 };
 
+struct logfs_super;	/* forward */
 /**
  * struct logfs_device_ops - device access operations
  *
@@ -156,7 +157,7 @@ struct logfs_device_ops {
 			int ensure_write);
 	int (*can_write_buf)(struct super_block *sb, u64 ofs);
 	void (*sync)(struct super_block *sb);
-	void (*put_device)(struct super_block *sb);
+	void (*put_device)(struct logfs_super *s);
 };
 
 /**

fs/logfs/super.c

@@ -529,7 +529,7 @@ static void logfs_kill_sb(struct super_block *sb)
 	logfs_cleanup_rw(sb);
 	if (super->s_erase_page)
 		__free_page(super->s_erase_page);
-	super->s_devops->put_device(sb);
+	super->s_devops->put_device(super);
 	logfs_mempool_destroy(super->s_btree_pool);
 	logfs_mempool_destroy(super->s_alias_pool);
 	kfree(super);
@@ -586,8 +586,8 @@ int logfs_get_sb_device(struct logfs_super *super,
 	deactivate_locked_super(sb);
 	return err;
 err0:
+	super->s_devops->put_device(super);
 	kfree(super);
-	//devops->put_device(sb);
 	return err;
 }