[PATCH 09/12] btrfs: support btrfs dev scan for spare device

[Anand Jain <anand.jain@oracle.com>]

When the user or system calls the BTRFS_IOC_SCAN_DEV,
ioctl this patch will make sure it is added to the device
list and set it as spare.

This operation will be same when BTRFS_IOC_DEVICES_READY
as well since BTRFS_IOC_DEVICES_READY ioctl has been doing
that by legacy.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 fs/btrfs/volumes.c | 4 ++++
 fs/btrfs/volumes.h | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a662701d4f22..26ae4fd39ce7 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -604,6 +604,10 @@ static noinline int device_list_add(const char *path,
 		if (IS_ERR(fs_devices))
 			return PTR_ERR(fs_devices);
 
+		if (btrfs_super_incompat_flags(disk_super) &
+				BTRFS_FEATURE_INCOMPAT_SPARE_DEV)
+			fs_devices->spare = 1;
+
 		list_add(&fs_devices->list, &fs_uuids);
 
 		device = NULL;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index ccc716b3c419..6b3b730c2727 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -276,6 +276,8 @@ struct btrfs_fs_devices {
 	struct kobject fsid_kobj;
 	struct kobject *device_dir_kobj;
 	struct completion kobj_unregister;
+
+	int spare;
 };
 
 #define BTRFS_BIO_INLINE_CSUM_SIZE	64
-- 
2.7.0