From: Jeff Mahoney <jeffm@suse.com>
Subject: btrfs: provide super_operations->inode_get_dev
References: bsc#927455
Patch-mainline: No, upstream wants a super_block per anon dev

In order to ensure that the per-subvolume anonymous dev_t gets published
to userspace, we need to provide the super_operations->get_inode_dev
operation.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
 fs/btrfs/super.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2264,6 +2264,11 @@ static int btrfs_show_devname(struct seq
 	return 0;
 }
 
+static dev_t btrfs_get_inode_dev(const struct inode *inode)
+{
+	return BTRFS_I(inode)->root->anon_dev;
+}
+
 static const struct super_operations btrfs_super_ops = {
 	.drop_inode	= btrfs_drop_inode,
 	.evict_inode	= btrfs_evict_inode,
@@ -2278,6 +2283,7 @@ static const struct super_operations btr
 	.remount_fs	= btrfs_remount,
 	.freeze_fs	= btrfs_freeze,
 	.unfreeze_fs	= btrfs_unfreeze,
+	.get_inode_dev	= btrfs_get_inode_dev,
 };
 
 static const struct file_operations btrfs_ctl_fops = {