Hi, 在 2024/01/24 10:58, Xiao Ni 写道:
Hi all MD_RECOVERY_WAIT was introduced in d5d885fd5. From this patch, MD_RECOVERY_WAIT only has one usage during creating raid device. resync job needs to wait until pers->start finishes(The only place which is checked). If we remove it from md_do_sync, will it break the logic? Or we don't need this flag anymore? If so can we remove this flag? dm-raid uses this bit in patch 644e2537f (dm raid: fix stripe adding reshape deadlock). It's the reason why md_do_sync can't set MD_RECOVERY_DONE. Now we stop sync thread asynchronously, can we revert this patch?
I made some changes that will be sent for v2 that sync_thread is frozen from dm suspend to resume, so I think the flag can be removed, and I actually tried that, howver, dm-raid tests failed because ext4 is corrupted. Anyway, let's focus on dm-raid regression for now and we can try to remove this flag later. Thanks, Kuai
Best Regards Xiao On Sat, Jan 20, 2024 at 6:41 PM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:From: Yu Kuai <yukuai3@xxxxxxxxxx> stop_sync_thread() will interrupt md_do_sync(), and md_do_sync() must set MD_RECOVERY_DONE, so that follow up md_check_recovery() will unregister sync_thread, clear MD_RECOVERY_RUNNING and wake up stop_sync_thread(). Before this patch, if MD_RECOVERY_WAIT is set or the array is read-only, md_do_sync() will return without setting MD_RECOVERY_DONE, hence use stop_sync_thread() directly will hang because md_check_recovery() can't clear MD_RECOVERY_RUNNING, which is possible for dm-raid. Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> --- drivers/md/md.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 6906d023f1d6..ba45c7be3dbe 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8788,12 +8788,13 @@ void md_do_sync(struct md_thread *thread) int ret; /* just incase thread restarts... */ - if (test_bit(MD_RECOVERY_DONE, &mddev->recovery) || - test_bit(MD_RECOVERY_WAIT, &mddev->recovery)) + if (test_bit(MD_RECOVERY_DONE, &mddev->recovery)) return; - if (!md_is_rdwr(mddev)) {/* never try to sync a read-only array */ + + if (test_bit(MD_RECOVERY_WAIT, &mddev->recovery) || + !md_is_rdwr(mddev)) {/* never try to sync a read-only array */ set_bit(MD_RECOVERY_INTR, &mddev->recovery); - return; + goto out; } if (mddev_is_clustered(mddev)) { @@ -9171,6 +9172,7 @@ void md_do_sync(struct md_thread *thread) mddev->array_sectors); } +out: spin_lock(&mddev->lock); if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) { /* We completed so min/max setting can be forgotten if used. */ -- 2.39.2.
