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Commit 28c1b9fd authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues Committed by NeilBrown
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md-cluster: Call update_raid_disks() if another node --grow's raid_disks 



To incorporate --grow feature executed on one node, other nodes need to
acknowledge the change in number of disks. Call update_raid_disks()
to update internal data structures.

This leads to call check_reshape() -> md_allow_write() -> md_update_sb(),
this results in a deadlock. This is done so it can safely allocate memory
(which might trigger writeback which might write to raid1). This is
not required for md with a bitmap.

In the clustered case, we don't perform md_update_sb() in md_allow_write(),
but in do_md_run(). Also we disable safemode for clustered mode.

mddev->recovery_cp need not be set in check_sb_changes() because this
is required only when a node reads another node's bitmap. mddev->recovery_cp
(which is read from sb->resync_offset), is set only if mddev is in_sync.
Since we disabled safemode, in_sync is set to zero.
In a clustered environment, the MD may not be in sync because another
node could be writing to it. So make sure that in_sync is not set in
case of clustered node in __md_stop_writes().

Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.com>
parent 30661b49

drivers/md/md.c

+18 −7
Original line number Diff line number Diff line
@@ -2230,7 +2230,6 @@ static bool does_sb_need_changing(struct mddev *mddev) 
	/* Check if any mddev parameters have changed */

	if ((mddev->dev_sectors != le64_to_cpu(sb->size)) ||

	    (mddev->reshape_position != le64_to_cpu(sb->reshape_position)) ||

	    (mddev->recovery_cp != le64_to_cpu(sb->resync_offset)) ||

	    (mddev->layout != le64_to_cpu(sb->layout)) ||

	    (mddev->raid_disks != le32_to_cpu(sb->raid_disks)) ||

	    (mddev->chunk_sectors != le32_to_cpu(sb->chunksize)))
@@ -3314,6 +3313,11 @@ safe_delay_store(struct mddev *mddev, const char *cbuf, size_t len) 
{

	unsigned long msec;



	if (mddev_is_clustered(mddev)) {

		pr_info("md: Safemode is disabled for clustered mode\n");

		return -EINVAL;

	}



	if (strict_strtoul_scaled(cbuf, &msec, 3) < 0)

		return -EINVAL;

	if (msec == 0)
@@ -5224,6 +5228,9 @@ int md_run(struct mddev *mddev) 
	atomic_set(&mddev->max_corr_read_errors,

		   MD_DEFAULT_MAX_CORRECTED_READ_ERRORS);

	mddev->safemode = 0;

	if (mddev_is_clustered(mddev))

		mddev->safemode_delay = 0;

	else

		mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */

	mddev->in_sync = 1;

	smp_wmb();
@@ -5267,6 +5274,9 @@ static int do_md_run(struct mddev *mddev) 
		goto out;

	}



	if (mddev_is_clustered(mddev))

		md_allow_write(mddev);



	md_wakeup_thread(mddev->thread);

	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
@@ -5363,8 +5373,10 @@ static void __md_stop_writes(struct mddev *mddev) 
	md_super_wait(mddev);



	if (mddev->ro == 0 &&

	    (!mddev->in_sync || (mddev->flags & MD_UPDATE_SB_FLAGS))) {

	    ((!mddev->in_sync && !mddev_is_clustered(mddev)) ||

	     (mddev->flags & MD_UPDATE_SB_FLAGS))) {

		/* mark array as shutdown cleanly */

		if (!mddev_is_clustered(mddev))

			mddev->in_sync = 1;

		md_update_sb(mddev, 1);

	}
@@ -9007,9 +9019,8 @@ static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev) 
		}

	}



	/* recovery_cp changed */

	if (le64_to_cpu(sb->resync_offset) != mddev->recovery_cp)

		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);

	if (mddev->raid_disks != le32_to_cpu(sb->raid_disks))

		update_raid_disks(mddev, le32_to_cpu(sb->raid_disks));



	/* Finally set the event to be up to date */

	mddev->events = le64_to_cpu(sb->events);

drivers/md/raid1.c

+5 −3
Original line number Diff line number Diff line
@@ -3044,9 +3044,11 @@ static int raid1_reshape(struct mddev *mddev) 
		return -EINVAL;

	}



	if (!mddev_is_clustered(mddev)) {

		err = md_allow_write(mddev);

		if (err)

			return err;

	}



	raid_disks = mddev->raid_disks + mddev->delta_disks;