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 (file)
--- 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 md_cluster_info {
        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 @@ static void process_suspend_info(struct md_cluster_info *cinfo,
        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 @@ static void process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)
                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 @@ static int join(struct mddev *mddev, int nodes)
        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 @@ err:
        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 @@ static int leave(struct mddev *mddev)
        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 @@ out:
        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 @@ static struct md_cluster_operations cluster_ops = {
        .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)

diff --git a/drivers/md/md-cluster.h b/drivers/md/md-cluster.h
index 0378540..60d7e58 100644 (file)
--- a/drivers/md/md-cluster.h
+++ b/drivers/md/md-cluster.h
@@ -6,6 +6,7 @@
 #include "md.h"
 
 struct mddev;
+struct md_rdev;
 
 struct md_cluster_operations {
        int (*join)(struct mddev *mddev, int nodes);
@@ -18,6 +19,9 @@ struct md_cluster_operations {
        int (*metadata_update_finish)(struct mddev *mddev);
        int (*metadata_update_cancel)(struct mddev *mddev);
        int (*area_resyncing)(struct mddev *mddev, sector_t lo, sector_t hi);
+       int (*add_new_disk_start)(struct mddev *mddev, struct md_rdev *rdev);
+       int (*add_new_disk_finish)(struct mddev *mddev);
+       void (*new_disk_ack)(struct mddev *mddev, bool ack);
 };
 
 #endif /* _MD_CLUSTER_H */

diff --git a/drivers/md/md.c b/drivers/md/md.c
index fe04846..5703c2e 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2210,7 +2210,7 @@ static void sync_sbs(struct mddev *mddev, int nospares)
        }
 }
 
-static void md_update_sb(struct mddev *mddev, int force_change)
+void md_update_sb(struct mddev *mddev, int force_change)
 {
        struct md_rdev *rdev;
        int sync_req;
@@ -2371,6 +2371,7 @@ repeat:
                wake_up(&rdev->blocked_wait);
        }
 }
+EXPORT_SYMBOL(md_update_sb);
 
 /* words written to sysfs files may, or may not, be \n terminated.
  * We want to accept with case. For this we use cmd_match.
@@ -3151,7 +3152,7 @@ static void analyze_sbs(struct mddev *mddev)
                        kick_rdev_from_array(rdev);
                        continue;
                }
-               if (rdev != freshest)
+               if (rdev != freshest) {
                        if (super_types[mddev->major_version].
                            validate_super(mddev, rdev)) {
                                printk(KERN_WARNING "md: kicking non-fresh %s"
@@ -3160,6 +3161,15 @@ static void analyze_sbs(struct mddev *mddev)
                                kick_rdev_from_array(rdev);
                                continue;
                        }
+                       /* No device should have a Candidate flag
+                        * when reading devices
+                        */
+                       if (test_bit(Candidate, &rdev->flags)) {
+                               pr_info("md: kicking Cluster Candidate %s from array!\n",
+                                       bdevname(rdev->bdev, b));
+                               kick_rdev_from_array(rdev);
+                       }
+               }
                if (mddev->level == LEVEL_MULTIPATH) {
                        rdev->desc_nr = i++;
                        rdev->raid_disk = rdev->desc_nr;
@@ -5655,7 +5665,6 @@ static int get_array_info(struct mddev *mddev, void __user *arg)
                info.state |= (1<<MD_SB_BITMAP_PRESENT);
        if (mddev_is_clustered(mddev))
                info.state |= (1<<MD_SB_CLUSTERED);
-
        info.active_disks  = insync;
        info.working_disks = working;
        info.failed_disks  = failed;
@@ -5744,6 +5753,13 @@ static int add_new_disk(struct mddev *mddev, mdu_disk_info_t *info)
        struct md_rdev *rdev;
        dev_t dev = MKDEV(info->major,info->minor);
 
+       if (mddev_is_clustered(mddev) &&
+               !(info->state & ((1 << MD_DISK_CLUSTER_ADD) | (1 << MD_DISK_CANDIDATE)))) {
+               pr_err("%s: Cannot add to clustered mddev. Try --cluster-add\n",
+                              mdname(mddev));
+               return -EINVAL;
+       }
+
        if (info->major != MAJOR(dev) || info->minor != MINOR(dev))
                return -EOVERFLOW;
 
@@ -5830,6 +5846,25 @@ static int add_new_disk(struct mddev *mddev, mdu_disk_info_t *info)
                else
                        clear_bit(WriteMostly, &rdev->flags);
 
+               /*
+                * check whether the device shows up in other nodes
+                */
+               if (mddev_is_clustered(mddev)) {
+                       if (info->state & (1 << MD_DISK_CANDIDATE)) {
+                               /* Through --cluster-confirm */
+                               set_bit(Candidate, &rdev->flags);
+                               md_cluster_ops->new_disk_ack(mddev, true);
+                       } else if (info->state & (1 << MD_DISK_CLUSTER_ADD)) {
+                               /* --add initiated by this node */
+                               err = md_cluster_ops->add_new_disk_start(mddev, rdev);
+                               if (err) {
+                                       md_cluster_ops->add_new_disk_finish(mddev);
+                                       export_rdev(rdev);
+                                       return err;
+                               }
+                       }
+               }
+
                rdev->raid_disk = -1;
                err = bind_rdev_to_array(rdev, mddev);
                if (!err && !mddev->pers->hot_remove_disk) {
@@ -5855,6 +5890,9 @@ static int add_new_disk(struct mddev *mddev, mdu_disk_info_t *info)
                if (!err)
                        md_new_event(mddev);
                md_wakeup_thread(mddev->thread);
+               if (mddev_is_clustered(mddev) &&
+                               (info->state & (1 << MD_DISK_CLUSTER_ADD)))
+                       md_cluster_ops->add_new_disk_finish(mddev);
                return err;
        }
 
@@ -6456,6 +6494,7 @@ static inline bool md_ioctl_valid(unsigned int cmd)
        case SET_DISK_FAULTY:
        case STOP_ARRAY:
        case STOP_ARRAY_RO:
+       case CLUSTERED_DISK_NACK:
                return true;
        default:
                return false;
@@ -6728,6 +6767,13 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
                goto unlock;
        }
 
+       case CLUSTERED_DISK_NACK:
+               if (mddev_is_clustered(mddev))
+                       md_cluster_ops->new_disk_ack(mddev, false);
+               else
+                       err = -EINVAL;
+               goto unlock;
+
        case HOT_ADD_DISK:
                err = hot_add_disk(mddev, new_decode_dev(arg));
                goto unlock;

diff --git a/drivers/md/md.h b/drivers/md/md.h
index bfebcfd..6dc0ce0 100644 (file)
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -171,6 +171,10 @@ enum flag_bits {
                                 * 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 struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 
 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,

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index f70d741..53ed5d4 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1571,6 +1571,7 @@ static int raid1_spare_active(struct mddev *mddev)
                struct md_rdev *rdev = conf->mirrors[i].rdev;
                struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
                if (repl
+                   && !test_bit(Candidate, &repl->flags)
                    && repl->recovery_offset == MaxSector
                    && !test_bit(Faulty, &repl->flags)
                    && !test_and_set_bit(In_sync, &repl->flags)) {

diff --git a/include/uapi/linux/raid/md_p.h b/include/uapi/linux/raid/md_p.h
index 643489d..2ae6131 100644 (file)
--- a/include/uapi/linux/raid/md_p.h
+++ b/include/uapi/linux/raid/md_p.h
@@ -78,6 +78,12 @@
 #define MD_DISK_ACTIVE         1 /* disk is running or spare disk */
 #define MD_DISK_SYNC           2 /* disk is in sync with the raid set */
 #define MD_DISK_REMOVED                3 /* disk is in sync with the raid set */
+#define MD_DISK_CLUSTER_ADD     4 /* Initiate a disk add across the cluster
+                                  * For clustered enviroments only.
+                                  */
+#define MD_DISK_CANDIDATE      5 /* disk is added as spare (local) until confirmed
+                                  * For clustered enviroments only.
+                                  */
 
 #define        MD_DISK_WRITEMOSTLY     9 /* disk is "write-mostly" is RAID1 config.
                                   * read requests will only be sent here in

diff --git a/include/uapi/linux/raid/md_u.h b/include/uapi/linux/raid/md_u.h
index 74e7c60..1cb8aa6 100644 (file)
--- a/include/uapi/linux/raid/md_u.h
+++ b/include/uapi/linux/raid/md_u.h
@@ -62,6 +62,7 @@
 #define STOP_ARRAY             _IO (MD_MAJOR, 0x32)
 #define STOP_ARRAY_RO          _IO (MD_MAJOR, 0x33)
 #define RESTART_ARRAY_RW       _IO (MD_MAJOR, 0x34)
+#define CLUSTERED_DISK_NACK    _IO (MD_MAJOR, 0x35)
 
 /* 63 partitions with the alternate major number (mdp) */
 #define MdpMinorShift 6