Commit fa1944bb authored by Xiao Ni's avatar Xiao Ni Committed by Song Liu
Browse files

md/raid5: Wait sync io to finish before changing group cnt 



One customer reports a bug: raid5 is hung when changing thread cnt
while resync is running. The stripes are all in conf->handle_list
and new threads can't handle them.

Commit b39f35eb ("md: don't quiesce in mddev_suspend()") removes
pers->quiesce from mddev_suspend/resume. Before this patch, mddev_suspend
needs to wait for all ios including sync io to finish. Now it's used
to only wait normal io.

Fix this by calling raid5_quiesce from raid5_store_group_thread_cnt
directly to wait all sync requests to finish before changing the group
cnt.

Fixes: b39f35eb ("md: don't quiesce in mddev_suspend()")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarXiao Ni <xni@redhat.com>
Reviewed-by: default avatarYu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20241106095124.74577-1-xni@redhat.com


Signed-off-by: default avatarSong Liu <song@kernel.org>
parent 4122fef1

drivers/md/raid5.c

+4 −0
Original line number Diff line number Diff line
@@ -7176,6 +7176,8 @@ raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len) 
	err = mddev_suspend_and_lock(mddev);

	if (err)

		return err;

	raid5_quiesce(mddev, true);



	conf = mddev->private;

	if (!conf)

		err = -ENODEV;
@@ -7197,6 +7199,8 @@ raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len) 
			kfree(old_groups);

		}

	}



	raid5_quiesce(mddev, false);

	mddev_unlock_and_resume(mddev);



	return err ?: len;