Commit 47525e59 authored May 22, 2012 by Jonathan Brassow Committed by NeilBrown May 22, 2012

DM RAID: Set recovery flags on resume



Properly initialize MD recovery flags when resuming device-mapper devices.

When a device-mapper device is suspended, all I/O must stop.  This is done by
calling 'md_stop_writes' and 'mddev_suspend'.  These calls in-turn manipulate
the recovery flags - including setting 'MD_RECOVERY_FROZEN'.  The DM device
may have been suspended while recovery was not yet complete, so the process
needs to pick-up where it left off.  Since 'mddev_resume' does not unset
'MD_RECOVERY_FROZEN' and set 'MD_RECOVERY_NEEDED', we must do it ourselves.
'MD_RECOVERY_NEEDED' can safely be set in 'mddev_resume', but 'MD_RECOVERY_FROZEN'
must be set outside of 'mddev_resume' due to how MD handles RAID reshaping.
(e.g.  It is possible for a user to delay reshaping a RAID5->RAID6 by purposefully
setting 'MD_RECOVERY_FROZEN'.  Clearing it in 'mddev_resume' would override the
desired behavior.)

Because 'mddev_resume' already unconditionally calls 'md_wakeup_thread(mddev->thread)'
there is no need to make this call from 'raid_resume' since it calls 'mddev_resume'.

Also clean up where  level_store calls mddev_resume() - it current
duplicates some of the funcitons of that call. - NB

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

parent 30b67645

drivers/md/dm-raid.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1252,9 +1252,9 @@ static void raid_resume(struct dm_target *ti)
		if (!rs->bitmap_loaded) {
		bitmap_load(&rs->md);
		rs->bitmap_loaded = 1;
		} else
		md_wakeup_thread(rs->md.thread);
		}

		clear_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
		mddev_resume(&rs->md);
		}

drivers/md/md.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -402,6 +402,7 @@ void mddev_resume(struct mddev *mddev)
		wake_up(&mddev->sb_wait);
		mddev->pers->quiesce(mddev, 0);

		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
		md_wakeup_thread(mddev->thread);
		md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
		}
		@@ -3673,10 +3674,8 @@ level_store(struct mddev mddev, const char buf, size_t len)
		del_timer_sync(&mddev->safemode_timer);
		}
		pers->run(mddev);
		mddev_resume(mddev);
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
		md_wakeup_thread(mddev->thread);
		mddev_resume(mddev);
		sysfs_notify(&mddev->kobj, NULL, "level");
		md_new_event(mddev);
		return rv;

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