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Commit 0bb0c105 authored by Song Liu's avatar Song Liu Committed by Shaohua Li
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md/raid5: use consistency_policy to remove journal feature 



When journal device of an array fails, the array is forced into read-only
mode. To make the array normal without adding another journal device, we
need to remove journal _feature_ from the array.

This patch allows remove journal _feature_ from an array, For journal
existing journal should be either missing or faulty.

To remove journal feature, it is necessary to remove the journal device
first:

  mdadm --fail /dev/md0 /dev/sdb
  mdadm: set /dev/sdb faulty in /dev/md0
  mdadm --remove /dev/md0 /dev/sdb
  mdadm: hot removed /dev/sdb from /dev/md0

Then the journal feature can be removed by echoing into the sysfs file:

 cat /sys/block/md0/md/consistency_policy
 journal

 echo resync > /sys/block/md0/md/consistency_policy
 cat /sys/block/md0/md/consistency_policy
 resync

Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 1ad45a9b

drivers/md/raid5.c

+36 −10
Original line number Diff line number Diff line
@@ -8292,17 +8292,41 @@ static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf) 
	}



	if (strncmp(buf, "ppl", 3) == 0 && !raid5_has_ppl(conf)) {

		/* ppl only works with RAID 5 */

		if (conf->level == 5) {

			mddev_suspend(mddev);

			set_bit(MD_HAS_PPL, &mddev->flags);

			err = log_init(conf, NULL);

			if (!err)

				raid5_reset_stripe_cache(mddev);

			mddev_resume(mddev);

	} else if (strncmp(buf, "resync", 6) == 0 && raid5_has_ppl(conf)) {

		} else

			err = -EINVAL;

	} else if (strncmp(buf, "resync", 6) == 0) {

		if (raid5_has_ppl(conf)) {

			mddev_suspend(mddev);

			log_exit(conf);

			raid5_reset_stripe_cache(mddev);

			mddev_resume(mddev);

		} else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&

			   r5l_log_disk_error(conf)) {

			bool journal_dev_exists = false;

			struct md_rdev *rdev;



			rdev_for_each(rdev, mddev)

				if (test_bit(Journal, &rdev->flags)) {

					journal_dev_exists = true;

					break;

				}



			if (!journal_dev_exists) {

				mddev_suspend(mddev);

				clear_bit(MD_HAS_JOURNAL, &mddev->flags);

				mddev_resume(mddev);

			} else  /* need remove journal device first */

				err = -EBUSY;

		} else

			err = -EINVAL;

	} else {

		err = -EINVAL;

	}
@@ -8337,6 +8361,7 @@ static struct md_personality raid6_personality = 
	.quiesce	= raid5_quiesce,

	.takeover	= raid6_takeover,

	.congested	= raid5_congested,

	.change_consistency_policy = raid5_change_consistency_policy,

};

static struct md_personality raid5_personality =

{
@@ -8385,6 +8410,7 @@ static struct md_personality raid4_personality = 
	.quiesce	= raid5_quiesce,

	.takeover	= raid4_takeover,

	.congested	= raid5_congested,

	.change_consistency_policy = raid5_change_consistency_policy,

};



static int __init raid5_init(void)