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Commit 1aee41f6 authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues
Browse files

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: default avatarLidong Zhong <lzhong@suse.com>
Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
parent 7d49ffcf

drivers/md/md-cluster.c

+103 −1
Original line number Diff line number Diff line
@@ -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 @@ static int join(struct mddev *mddev, int nodes) 
	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 @@ static int area_resyncing(struct mddev *mddev, sector_t lo, sector_t hi) 
	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)

drivers/md/md-cluster.h

+4 −0
Original line number Diff line number Diff line
@@ -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 */

drivers/md/md.c

+49 −3
Original line number Diff line number Diff line
@@ -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 @@ static void md_update_sb(struct mddev *mddev, int force_change) 
		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;

drivers/md/md.h

+5 −0
Original line number Diff line number Diff line
@@ -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,

drivers/md/raid1.c

+1 −0
Original line number Diff line number Diff line
@@ -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)) {