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 b39f35ebe8 ("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: b39f35ebe8 ("md: don't quiesce in mddev_suspend()")
Cc: stable@vger.kernel.org
Signed-off-by: Xiao Ni <xni@redhat.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20241106095124.74577-1-xni@redhat.com
Signed-off-by: Song Liu <song@kernel.org>
This commit is contained in:
Xiao Ni 2024-11-06 17:51:24 +08:00 committed by Song Liu
parent 4122fef16b
commit fa1944bbe6

View File

@ -7176,6 +7176,8 @@ raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
err = mddev_suspend_and_lock(mddev); err = mddev_suspend_and_lock(mddev);
if (err) if (err)
return err; return err;
raid5_quiesce(mddev, true);
conf = mddev->private; conf = mddev->private;
if (!conf) if (!conf)
err = -ENODEV; err = -ENODEV;
@ -7197,6 +7199,8 @@ raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
kfree(old_groups); kfree(old_groups);
} }
} }
raid5_quiesce(mddev, false);
mddev_unlock_and_resume(mddev); mddev_unlock_and_resume(mddev);
return err ?: len; return err ?: len;