Commit 09539f9e authored May 12, 2023 by Yu Kuai Committed by Greg Kroah-Hartman Jul 27, 2023

md: fix data corruption for raid456 when reshape restart while grow up



[ Upstream commit 873f50ece41aad5c4f788a340960c53774b5526e ]

Currently, if reshape is interrupted, echo "reshape" to sync_action will
restart reshape from scratch, for example:

echo frozen > sync_action
echo reshape > sync_action

This will corrupt data before reshape_position if the array is growing,
fix the problem by continue reshape from reshape_position.

Reported-by: Peter Neuwirth <reddunur@online.de>
Link: https://lore.kernel.org/linux-raid/e2f96772-bfbc-f43b-6da1-f520e5164536@online.de/


Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230512015610.821290-3-yukuai1@huaweicloud.com


Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 4181c30a

drivers/md/md.c

+12 −2

Original line number	Diff line number	Diff line
		@@ -4743,11 +4743,21 @@ action_store(struct mddev mddev, const char page, size_t len)
		return -EINVAL;
		err = mddev_lock(mddev);
		if (!err) {
		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
		err = -EBUSY;
		else {
		} else if (mddev->reshape_position == MaxSector \|\|
		mddev->pers->check_reshape == NULL \|\|
		mddev->pers->check_reshape(mddev)) {
		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
		err = mddev->pers->start_reshape(mddev);
		} else {
		/*
		* If reshape is still in progress, and
		* md_check_recovery() can continue to reshape,
		* don't restart reshape because data can be
		* corrupted for raid456.
		*/
		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
		}
		mddev_unlock(mddev);
		}