On Mon, Sep 02 2019, Yufen Yu wrote: > On 2019/9/2 15:34, NeilBrown wrote: >> On Mon, Sep 02 2019, Yufen Yu wrote: >> >>> When active disk in raid1 array less than one, we need to return >>> fail to run. >> Seems reasonable, but how can this happen? >> As we never fail the last device in a RAID1, there should always >> appear to be one that is working. >> >> Have you had a situation where this in actually needed? > > There is a situation we found in follow patch. > https://marc.info/?l=linux-raid&m=156740736305042&w=2 Ahhh - thanks. Multiple cascading failures there, but is certainly could happen. As I said, I think the patch make sense. IT might be a good idea to add the reproduced from the linked email to the patch description. You can also add Reviewed-by: NeilBrown <neilb@xxxxxxx> Thanks, NeilBrown > > Though we can fix that situation, I am not sure whether other situation > can also cause the active disk less than one. > > Thanks > Yufen > >> >> Thanks, >> NeilBrown >> >>> Signed-off-by: Yufen Yu <yuyufen@xxxxxxxxxx> >>> --- >>> drivers/md/raid1.c | 13 ++++++++++++- >>> 1 file changed, 12 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c >>> index 34e26834ad28..2a554464d6a4 100644 >>> --- a/drivers/md/raid1.c >>> +++ b/drivers/md/raid1.c >>> @@ -3127,6 +3127,13 @@ static int raid1_run(struct mddev *mddev) >>> !test_bit(In_sync, &conf->mirrors[i].rdev->flags) || >>> test_bit(Faulty, &conf->mirrors[i].rdev->flags)) >>> mddev->degraded++; >>> + /* >>> + * RAID1 needs at least one disk in active >>> + */ >>> + if (conf->raid_disks - mddev->degraded < 1) { >>> + ret = -EINVAL; >>> + goto abort; >>> + } >>> >>> if (conf->raid_disks - mddev->degraded == 1) >>> mddev->recovery_cp = MaxSector; >>> @@ -3160,8 +3167,12 @@ static int raid1_run(struct mddev *mddev) >>> ret = md_integrity_register(mddev); >>> if (ret) { >>> md_unregister_thread(&mddev->thread); >>> - raid1_free(mddev, conf); >>> + goto abort; >>> } >>> + return 0; >>> + >>> +abort: >>> + raid1_free(mddev, conf); >>> return ret; >>> } >>> >>> -- >>> 2.17.2
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