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Commit 644e2537 authored by Heinz Mauelshagen's avatar Heinz Mauelshagen Committed by Mike Snitzer
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dm raid: fix stripe adding reshape deadlock 



When initiating a stripe adding reshape, a deadlock between
md_stop_writes() waiting for the sync thread to stop and the running
sync thread waiting for inactive stripes occurs (this frequently happens
on single-core but rarely on multi-core systems).

Fix this deadlock by setting MD_RECOVERY_WAIT to have the main MD
resynchronization thread worker (md_do_sync()) bail out when initiating
the reshape via constructor arguments.

Signed-off-by: default avatarHeinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 38b0bd0c

drivers/md/dm-raid.c

+3 −8
Original line number Diff line number Diff line
@@ -3869,14 +3869,13 @@ static int rs_start_reshape(struct raid_set *rs) 
	struct mddev *mddev = &rs->md;

	struct md_personality *pers = mddev->pers;



	/* Don't allow the sync thread to work until the table gets reloaded. */

	set_bit(MD_RECOVERY_WAIT, &mddev->recovery);



	r = rs_setup_reshape(rs);

	if (r)

		return r;



	/* Need to be resumed to be able to start reshape, recovery is frozen until raid_resume() though */

	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))

		mddev_resume(mddev);



	/*

	 * Check any reshape constraints enforced by the personalility

	 *
@@ -3900,10 +3899,6 @@ static int rs_start_reshape(struct raid_set *rs) 
		}

	}



	/* Suspend because a resume will happen in raid_resume() */

	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);

	mddev_suspend(mddev);



	/*

	 * Now reshape got set up, update superblocks to

	 * reflect the fact so that a table reload will