From mboxrd@z Thu Jan 1 00:00:00 1970 From: "heming.zhao@suse.com" Subject: Re: [PATCH v4 1/2] md-cluster: fix safemode_delay value when converting to clustered bitmap Date: Tue, 21 Jul 2020 00:03:06 +0800 Message-ID: References: <1595156920-31427-1-git-send-email-heming.zhao@suse.com> <1595156920-31427-2-git-send-email-heming.zhao@suse.com> <87k0yzw0km.fsf@notabene.neil.brown.name> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <87k0yzw0km.fsf@notabene.neil.brown.name> Content-Language: en-US Sender: linux-raid-owner@vger.kernel.org To: NeilBrown , linux-raid@vger.kernel.org Cc: neilb@suse.com List-Id: linux-raid.ids On 7/20/20 7:24 AM, NeilBrown wrote: > On Sun, Jul 19 2020, Zhao Heming wrote: > >> When array convert to clustered bitmap, the safe_mode_delay doesn't clean and vice versa. >> the /sys/block/mdX/md/safe_mode_delay keep original value after changing bitmap type. >> in safe_delay_store(), the code forbids setting mddev->safemode_delay when array is clustered. >> So in cluster-md env, the expected safemode_delay value should be 0. >> >> reproduction steps: >> ``` >> node1 # mdadm --zero-superblock /dev/sd{b,c,d} >> node1 # mdadm -C /dev/md0 -b internal -e 1.2 -n 2 -l mirror /dev/sdb /dev/sdc >> node1 # cat /sys/block/md0/md/safe_mode_delay >> 0.204 >> node1 # mdadm -G /dev/md0 -b none >> node1 # mdadm --grow /dev/md0 --bitmap=clustered >> node1 # cat /sys/block/md0/md/safe_mode_delay >> 0.204 <== doesn't change, should ZERO for cluster-md >> >> node1 # mdadm --zero-superblock /dev/sd{b,c,d} >> node1 # mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sdb /dev/sdc >> node1 # cat /sys/block/md0/md/safe_mode_delay >> 0.000 >> node1 # mdadm -G /dev/md0 -b none >> node1 # cat /sys/block/md0/md/safe_mode_delay >> 0.000 <== doesn't change, should default value >> ``` >> >> md_setup_cluster() is a good place for setting, but md_cluster_stop is >> good for clean job when md_setup_cluster return err. >> >> see below flow: >> (user space) >> mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda /dev/sdb >> mdadm --grow /dev/md0 -b none >> (kernel space) >> SET_ARRAY_INFO >> update_array_info >> + mddev->bitmap_info.nodes = 0; >> + md_cluster_ops->leave(mddev) >> + md_bitmap_destroy >> md_bitmap_free //won't trigger md_cluster_stop() because above set 0. >> >> Signed-off-by: Zhao Heming >> --- >> drivers/md/md.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/md/md.c b/drivers/md/md.c >> index f567f536b529..e20f1d5a5261 100644 >> --- a/drivers/md/md.c >> +++ b/drivers/md/md.c >> @@ -101,6 +101,8 @@ static void mddev_detach(struct mddev *mddev); >> * count by 2 for every hour elapsed between read errors. >> */ >> #define MD_DEFAULT_MAX_CORRECTED_READ_ERRORS 20 >> +/* Default safemode delay: 200 msec */ >> +#define DEFAULT_SAFEMODE_DELAY ((200 * HZ)/1000 +1) >> /* >> * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit' >> * is 1000 KB/sec, so the extra system load does not show up that much. >> @@ -5982,7 +5984,7 @@ int md_run(struct mddev *mddev) >> if (mddev_is_clustered(mddev)) >> mddev->safemode_delay = 0; >> else >> - mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */ >> + mddev->safemode_delay = DEFAULT_SAFEMODE_DELAY; >> mddev->in_sync = 1; >> smp_wmb(); >> spin_lock(&mddev->lock); >> @@ -7361,6 +7363,7 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info) >> >> mddev->bitmap_info.nodes = 0; >> md_cluster_ops->leave(mddev); >> + mddev->safemode_delay = DEFAULT_SAFEMODE_DELAY; >> } >> mddev_suspend(mddev); >> md_bitmap_destroy(mddev); >> @@ -8366,6 +8369,7 @@ int md_setup_cluster(struct mddev *mddev, int nodes) >> } >> spin_unlock(&pers_lock); >> >> + mddev->safemode_delay = 0; >> return md_cluster_ops->join(mddev, nodes); > > I still don't think you should change safemode_delay here until after > ->join succeeds. > > NeilBrown you are right, it makes a gap to set delay to zero before join(). I will following your comments. > >> } >> >> @@ -8375,6 +8379,7 @@ void md_cluster_stop(struct mddev *mddev) >> return; >> md_cluster_ops->leave(mddev); >> module_put(md_cluster_mod); >> + mddev->safemode_delay = DEFAULT_SAFEMODE_DELAY; >> } >> >> static int is_mddev_idle(struct mddev *mddev, int init) >> -- >> 2.25.0