| Message ID | 20240801125148.251986-1-yukuai1@huaweicloud.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [-next] md: wake up mdmon after setting badblocks | expand |
| Context | Check | Description |
|---|---|---|
| mdraidci/vmtest-md-6_11-PR | success | PR summary |
| mdraidci/vmtest-md-6_11-VM_Test-0 | success | Logs for build-kernel |
On Thu, 1 Aug 2024 20:51:48 +0800 Yu Kuai <yukuai1@huaweicloud.com> wrote: > From: Yu Kuai <yukuai3@huawei.com> > > For external super_block, mdmon rely on "mddev->sysfs_state" to update > super_block. However, rdev_set_badblocks() will set sb_flags without > waking up mdmon, which might cauing IO hang due to suepr_block can't be > updated. > > This problem is found by code review. > > Signed-off-by: Yu Kuai <yukuai3@huawei.com> > --- > drivers/md/md.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/md/md.c b/drivers/md/md.c > index 23cc77d51676..06d6ee8cd543 100644 > --- a/drivers/md/md.c > +++ b/drivers/md/md.c > @@ -9831,10 +9831,12 @@ int rdev_set_badblocks(struct md_rdev *rdev, sector_t > s, int sectors, /* Make sure they get written out promptly */ > if (test_bit(ExternalBbl, &rdev->flags)) > sysfs_notify_dirent_safe(rdev->sysfs_unack_badblocks); > - sysfs_notify_dirent_safe(rdev->sysfs_state); > set_mask_bits(&mddev->sb_flags, 0, > BIT(MD_SB_CHANGE_CLEAN) | > BIT(MD_SB_CHANGE_PENDING)); md_wakeup_thread(rdev->mddev->thread); > + > + sysfs_notify_dirent_safe(rdev->sysfs_state); > + sysfs_notify_dirent_safe(mddev->sysfs_state); > return 1; > } else > return 0; Hey Kuai, Later, I realized that mdmon is attached to various fds: Here a mdmon code: add_fd(&rfds, &maxfd, a->info.state_fd); #mddev->sysfs_state add_fd(&rfds, &maxfd, a->action_fd); #mddev->sysfs_action add_fd(&rfds, &maxfd, a->sync_completed_fd); #mddev->resync_position for (mdi = a->info.devs ; mdi ; mdi = mdi->next) { #for each rdev add_fd(&rfds, &maxfd, mdi->state_fd); #rdev->sysfs_state add_fd(&rfds, &maxfd, mdi->bb_fd); #rdev->sysfs_badblocks add_fd(&rfds, &maxfd, mdi->ubb_fd); #rdev->sysfs_unack_badblocks } Notification in rdev->sysfs_state is fine. The problem was somewhere else (mdmon blocked on "rdev remove"). And It will be fixed by moving rdev remove to managemon because it is blocking action now. https://github.com/md-raid-utilities/mdadm/pull/66 I think it is fine to move this down after set_mask_bits, but we don't have to repeat notification to mddev->state. Thanks, Mariusz
Hi, 在 2024/08/05 17:40, Mariusz Tkaczyk 写道: > On Thu, 1 Aug 2024 20:51:48 +0800 > Yu Kuai <yukuai1@huaweicloud.com> wrote: > >> From: Yu Kuai <yukuai3@huawei.com> >> >> For external super_block, mdmon rely on "mddev->sysfs_state" to update >> super_block. However, rdev_set_badblocks() will set sb_flags without >> waking up mdmon, which might cauing IO hang due to suepr_block can't be >> updated. >> >> This problem is found by code review. >> >> Signed-off-by: Yu Kuai <yukuai3@huawei.com> >> --- >> drivers/md/md.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/md/md.c b/drivers/md/md.c >> index 23cc77d51676..06d6ee8cd543 100644 >> --- a/drivers/md/md.c >> +++ b/drivers/md/md.c >> @@ -9831,10 +9831,12 @@ int rdev_set_badblocks(struct md_rdev *rdev, sector_t >> s, int sectors, /* Make sure they get written out promptly */ >> if (test_bit(ExternalBbl, &rdev->flags)) >> sysfs_notify_dirent_safe(rdev->sysfs_unack_badblocks); >> - sysfs_notify_dirent_safe(rdev->sysfs_state); >> set_mask_bits(&mddev->sb_flags, 0, >> BIT(MD_SB_CHANGE_CLEAN) | >> BIT(MD_SB_CHANGE_PENDING)); md_wakeup_thread(rdev->mddev->thread); >> + >> + sysfs_notify_dirent_safe(rdev->sysfs_state); >> + sysfs_notify_dirent_safe(mddev->sysfs_state); >> return 1; >> } else >> return 0; > > > Hey Kuai, > Later, I realized that mdmon is attached to various fds: > > Here a mdmon code: > > add_fd(&rfds, &maxfd, a->info.state_fd); #mddev->sysfs_state > add_fd(&rfds, &maxfd, a->action_fd); #mddev->sysfs_action > add_fd(&rfds, &maxfd, a->sync_completed_fd); #mddev->resync_position > > > for (mdi = a->info.devs ; mdi ; mdi = mdi->next) { #for each rdev > add_fd(&rfds, &maxfd, mdi->state_fd); #rdev->sysfs_state > add_fd(&rfds, &maxfd, mdi->bb_fd); #rdev->sysfs_badblocks > add_fd(&rfds, &maxfd, mdi->ubb_fd); > #rdev->sysfs_unack_badblocks } Ok, so I was wrong that mdmon rely on "mddev->sysfs_state". > > Notification in rdev->sysfs_state is fine. The problem was somewhere else > (mdmon blocked on "rdev remove"). And It will be fixed by moving rdev remove to > managemon because it is blocking action now. > > https://github.com/md-raid-utilities/mdadm/pull/66 > > I think it is fine to move this down after set_mask_bits, but we don't > have to repeat notification to mddev->state. Yes, I'll send a v2 patch to move down "rdev->sysfs_state". Thanks, Kuai > > Thanks, > Mariusz > > . >
diff --git a/drivers/md/md.c b/drivers/md/md.c index 23cc77d51676..06d6ee8cd543 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9831,10 +9831,12 @@ int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors, /* Make sure they get written out promptly */ if (test_bit(ExternalBbl, &rdev->flags)) sysfs_notify_dirent_safe(rdev->sysfs_unack_badblocks); - sysfs_notify_dirent_safe(rdev->sysfs_state); set_mask_bits(&mddev->sb_flags, 0, BIT(MD_SB_CHANGE_CLEAN) | BIT(MD_SB_CHANGE_PENDING)); md_wakeup_thread(rdev->mddev->thread); + + sysfs_notify_dirent_safe(rdev->sysfs_state); + sysfs_notify_dirent_safe(mddev->sysfs_state); return 1; } else return 0;