Add new disk to clustered array
Algorithm:
1. Node 1 issues mdadm --manage /dev/mdX --add /dev/sdYY which issues
ioctl(ADD_NEW_DISC with disc.state set to MD_DISK_CLUSTER_ADD)
2. Node 1 sends NEWDISK with uuid and slot number
3. Other nodes issue kobject_uevent_env with uuid and slot number
(Steps 4,5 could be a udev rule)
4. In userspace, the node searches for the disk, perhaps
using blkid -t SUB_UUID=""
5. Other nodes issue either of the following depending on whether the disk
was found:
ioctl(ADD_NEW_DISK with disc.state set to MD_DISK_CANDIDATE and
disc.number set to slot number)
ioctl(CLUSTERED_DISK_NACK)
6. Other nodes drop lock on no-new-devs (CR) if device is found
7. Node 1 attempts EX lock on no-new-devs
8. If node 1 gets the lock, it sends METADATA_UPDATED after unmarking the disk
as SpareLocal
9. If not (get no-new-dev lock), it fails the operation and sends METADATA_UPDATED
10. Other nodes understand if the device is added or not by reading the superblock again after receiving the METADATA_UPDATED message.
Signed-off-by: Lidong Zhong <lzhong@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
diff --git a/drivers/md/md.h b/drivers/md/md.h
index bfebcfd..6dc0ce0 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -171,6 +171,10 @@
* a want_replacement device with same
* raid_disk number.
*/
+ Candidate, /* For clustered environments only:
+ * This device is seen locally but not
+ * by the whole cluster
+ */
};
#define BB_LEN_MASK (0x00000000000001FFULL)
@@ -666,6 +670,7 @@
extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
extern void md_reload_sb(struct mddev *mddev);
+extern void md_update_sb(struct mddev *mddev, int force);
static inline int mddev_check_plugged(struct mddev *mddev)
{
return !!blk_check_plugged(md_unplug, mddev,