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-cluster.c b/drivers/md/md-cluster.c
index d85a6ca..03e521a 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -12,11 +12,13 @@
#include <linux/module.h>
#include <linux/dlm.h>
#include <linux/sched.h>
+#include <linux/raid/md_p.h>
#include "md.h"
#include "bitmap.h"
#include "md-cluster.h"
#define LVB_SIZE 64
+#define NEW_DEV_TIMEOUT 5000
struct dlm_lock_resource {
dlm_lockspace_t *ls;
@@ -56,19 +58,25 @@
struct dlm_lock_resource *ack_lockres;
struct dlm_lock_resource *message_lockres;
struct dlm_lock_resource *token_lockres;
+ struct dlm_lock_resource *no_new_dev_lockres;
struct md_thread *recv_thread;
+ struct completion newdisk_completion;
};
enum msg_type {
METADATA_UPDATED = 0,
RESYNCING,
+ NEWDISK,
};
struct cluster_msg {
int type;
int slot;
+ /* TODO: Unionize this for smaller footprint */
sector_t low;
sector_t high;
+ char uuid[16];
+ int raid_slot;
};
static void sync_ast(void *arg)
@@ -358,13 +366,41 @@
spin_unlock_irq(&cinfo->suspend_lock);
}
+static void process_add_new_disk(struct mddev *mddev, struct cluster_msg *cmsg)
+{
+ char disk_uuid[64];
+ struct md_cluster_info *cinfo = mddev->cluster_info;
+ char event_name[] = "EVENT=ADD_DEVICE";
+ char raid_slot[16];
+ char *envp[] = {event_name, disk_uuid, raid_slot, NULL};
+ int len;
+
+ len = snprintf(disk_uuid, 64, "DEVICE_UUID=");
+ pretty_uuid(disk_uuid + len, cmsg->uuid);
+ snprintf(raid_slot, 16, "RAID_DISK=%d", cmsg->raid_slot);
+ pr_info("%s:%d Sending kobject change with %s and %s\n", __func__, __LINE__, disk_uuid, raid_slot);
+ init_completion(&cinfo->newdisk_completion);
+ kobject_uevent_env(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE, envp);
+ wait_for_completion_timeout(&cinfo->newdisk_completion,
+ NEW_DEV_TIMEOUT);
+}
+
+
+static void process_metadata_update(struct mddev *mddev, struct cluster_msg *msg)
+{
+ struct md_cluster_info *cinfo = mddev->cluster_info;
+
+ md_reload_sb(mddev);
+ dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
+}
+
static void process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)
{
switch (msg->type) {
case METADATA_UPDATED:
pr_info("%s: %d Received message: METADATA_UPDATE from %d\n",
__func__, __LINE__, msg->slot);
- md_reload_sb(mddev);
+ process_metadata_update(mddev, msg);
break;
case RESYNCING:
pr_info("%s: %d Received message: RESYNCING from %d\n",
@@ -372,6 +408,10 @@
process_suspend_info(mddev->cluster_info, msg->slot,
msg->low, msg->high);
break;
+ case NEWDISK:
+ pr_info("%s: %d Received message: NEWDISK from %d\n",
+ __func__, __LINE__, msg->slot);
+ process_add_new_disk(mddev, msg);
};
}
@@ -593,10 +633,18 @@
cinfo->ack_lockres = lockres_init(mddev, "ack", ack_bast, 0);
if (!cinfo->ack_lockres)
goto err;
+ cinfo->no_new_dev_lockres = lockres_init(mddev, "no-new-dev", NULL, 0);
+ if (!cinfo->no_new_dev_lockres)
+ goto err;
+
/* get sync CR lock on ACK. */
if (dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_CR))
pr_err("md-cluster: failed to get a sync CR lock on ACK!(%d)\n",
ret);
+ /* get sync CR lock on no-new-dev. */
+ if (dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR))
+ pr_err("md-cluster: failed to get a sync CR lock on no-new-dev!(%d)\n", ret);
+
pr_info("md-cluster: Joined cluster %s slot %d\n", str, cinfo->slot_number);
snprintf(str, 64, "bitmap%04d", cinfo->slot_number - 1);
@@ -621,6 +669,7 @@
lockres_free(cinfo->message_lockres);
lockres_free(cinfo->token_lockres);
lockres_free(cinfo->ack_lockres);
+ lockres_free(cinfo->no_new_dev_lockres);
lockres_free(cinfo->bitmap_lockres);
lockres_free(cinfo->sb_lock);
if (cinfo->lockspace)
@@ -642,6 +691,7 @@
lockres_free(cinfo->message_lockres);
lockres_free(cinfo->token_lockres);
lockres_free(cinfo->ack_lockres);
+ lockres_free(cinfo->no_new_dev_lockres);
lockres_free(cinfo->sb_lock);
lockres_free(cinfo->bitmap_lockres);
dlm_release_lockspace(cinfo->lockspace, 2);
@@ -742,6 +792,55 @@
return ret;
}
+static int add_new_disk_start(struct mddev *mddev, struct md_rdev *rdev)
+{
+ struct md_cluster_info *cinfo = mddev->cluster_info;
+ struct cluster_msg cmsg;
+ int ret = 0;
+ struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
+ char *uuid = sb->device_uuid;
+
+ memset(&cmsg, 0, sizeof(cmsg));
+ cmsg.type = cpu_to_le32(NEWDISK);
+ memcpy(cmsg.uuid, uuid, 16);
+ cmsg.raid_slot = rdev->desc_nr;
+ lock_comm(cinfo);
+ ret = __sendmsg(cinfo, &cmsg);
+ if (ret)
+ return ret;
+ cinfo->no_new_dev_lockres->flags |= DLM_LKF_NOQUEUE;
+ ret = dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_EX);
+ cinfo->no_new_dev_lockres->flags &= ~DLM_LKF_NOQUEUE;
+ /* Some node does not "see" the device */
+ if (ret == -EAGAIN)
+ ret = -ENOENT;
+ else
+ dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
+ return ret;
+}
+
+static int add_new_disk_finish(struct mddev *mddev)
+{
+ struct cluster_msg cmsg;
+ struct md_cluster_info *cinfo = mddev->cluster_info;
+ int ret;
+ /* Write sb and inform others */
+ md_update_sb(mddev, 1);
+ cmsg.type = METADATA_UPDATED;
+ ret = __sendmsg(cinfo, &cmsg);
+ unlock_comm(cinfo);
+ return ret;
+}
+
+static void new_disk_ack(struct mddev *mddev, bool ack)
+{
+ struct md_cluster_info *cinfo = mddev->cluster_info;
+
+ if (ack)
+ dlm_unlock_sync(cinfo->no_new_dev_lockres);
+ complete(&cinfo->newdisk_completion);
+}
+
static struct md_cluster_operations cluster_ops = {
.join = join,
.leave = leave,
@@ -753,6 +852,9 @@
.metadata_update_finish = metadata_update_finish,
.metadata_update_cancel = metadata_update_cancel,
.area_resyncing = area_resyncing,
+ .add_new_disk_start = add_new_disk_start,
+ .add_new_disk_finish = add_new_disk_finish,
+ .new_disk_ack = new_disk_ack,
};
static int __init cluster_init(void)