Re: fstrim on raid1 LV with writemostly PV leads to system freeze
From: Kirill Kirilenko <hidden>
Date: 2023-09-25 23:59:08
Also in:
dm-devel
Possibly related (same subject, not in this thread)
- 2023-09-26 · Re: fstrim on raid1 LV with writemostly PV leads to system freeze · Kirill Kirilenko <hidden>
- 2023-09-26 · Re: fstrim on raid1 LV with writemostly PV leads to system freeze · Yu Kuai <hidden>
On 25.09.2023 05:58 +0300, Yu Kuai wrote:
quoted hunk ↗ jump to hunk
Roman and Kirill, can you test the following patch? Thanks, Kuaidiff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 4b30a1742162..4963f864ef99 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c@@ -1345,6 +1345,7 @@ static void raid1_write_request(struct mddev*mddev, struct bio *bio, int first_clone; int max_sectors; bool write_behind = false; + bool is_discard = (bio_op(bio) == REQ_OP_DISCARD); if (mddev_is_clustered(mddev) && md_cluster_ops->area_resyncing(mddev, WRITE,@@ -1405,7 +1406,7 @@ static void raid1_write_request(struct mddev*mddev, struct bio *bio, * write-mostly, which means we could allocate write behind * bio later. */ - if (rdev && test_bit(WriteMostly, &rdev->flags)) + if (!is_discard && rdev && test_bit(WriteMostly, &rdev->flags)) write_behind = true; if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
Thank you. I can confirm, that your patch eliminates freezes during 'fstrim' execution. Tested on kernel 6.5.0. Still 'fstrim' takes more than 2 minutes, but I believe it's normal to a file system with 1M+ inodes. Probably I'm wrong here, but to me this doesn't look like a solution, more like a masking the real problem. Even with TRIM operations split in 1MB pieces, I don't expect kernel to freeze.