[PATCH] btrfs: handle add/remove of sysfs links when devices are added/removed

[Jeff Mahoney <jeffm@suse.com>]

btrfs currently publishes device membership via sysfs based on the devices
present when the file system is mounted. That publishing is not updated
when devices are added or removed while mounted.

This patch handles those events.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
 fs/btrfs/volumes.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1704,6 +1704,9 @@ int btrfs_rm_device(struct btrfs_root *r
 
 	ret = 0;
 
+	sysfs_remove_link(root->fs_info->device_dir_kobj,
+			  part_to_dev(bdev->bd_part)->kobj.name);
+
 	/* Notify udev that device has changed */
 	if (bdev)
 		btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
@@ -2038,6 +2041,12 @@ int btrfs_init_new_device(struct btrfs_r
 		goto error;
 	}
 
+	ret = sysfs_create_link(root->fs_info->device_dir_kobj,
+				&part_to_dev(bdev->bd_part)->kobj,
+				part_to_dev(bdev->bd_part)->kobj.name);
+	if (ret)
+		goto error;
+
 	lock_chunks(root);
 
 	q = bdev_get_queue(bdev);
@@ -2152,6 +2161,8 @@ error_trans:
 	unlock_chunks(root);
 	btrfs_end_transaction(trans, root);
 	rcu_string_free(device->name);
+	sysfs_remove_link(root->fs_info->device_dir_kobj,
+			  part_to_dev(bdev->bd_part)->kobj.name);
 	kfree(device);
 error:
 	blkdev_put(bdev, FMODE_EXCL);

-- 
Jeff Mahoney
SUSE Labs