dm raid: fix stripe adding reshape deadlock (644e2537) · Commits · 戴 / test

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:

Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by:

Mike Snitzer <snitzer@redhat.com>

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

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