From bde8237d8360c8fd87d5dcb6fd15d0e5a9abef92 Mon Sep 17 00:00:00 2001 From: Xiao Ni Date: Wed, 12 Mar 2025 22:51:00 +0900 Subject: [PATCH] md/raid5: Wait sync io to finish before changing group cnt BugLink: https://bugs.launchpad.net/bugs/2102118 commit fa1944bbe6220eb929e2c02e5e8706b908565711 upstream. 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 b39f35ebe86d ("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: b39f35ebe86d ("md: don't quiesce in mddev_suspend()") Cc: stable@vger.kernel.org Signed-off-by: Xiao Ni Reviewed-by: Yu Kuai Link: https://lore.kernel.org/r/20241106095124.74577-1-xni@redhat.com Signed-off-by: Song Liu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/md/raid5.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index c7b7a4a9bbce..79b4c62ad696 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -7189,6 +7189,8 @@ 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; @@ -7210,6 +7212,8 @@ 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;