| Message ID | 1440629555.2196.92.camel@HansenPartnership.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 08/27/2015 12:52 AM, James Bottomley wrote: > On Wed, 2015-08-26 at 08:40 +0200, Hannes Reinecke wrote: >> On 08/26/2015 06:53 AM, Anatol Pomozov wrote: >>> Hi >>> >>> On Sun, Aug 23, 2015 at 11:15 PM, Hannes Reinecke <hare@suse.de> wrote: >>>>> I looked at this commit and it actually adds SMR support to SCSI >>>>> layer. Reverting ATA_DEV_ZAC means going back to zones-unaware >>>>> algorithms. It is suboptimal but still much better than IO failures >>>>> and "BTRFS: lost page write due to I/O error on /dev/sdc" errors I see >>>>> at my computer. >>>>> >>>>> If this SMR support is considered as non-stable, can we at least get a >>>>> kernel boot (or config) option that disables ZAC? >>>>> >>>> Again: Has anybody actually _tested_ that reverting this patch fixes >>>> this issue? >>> >>> Yes I tested it. >>> >>> This error happens only under heavy load with a lot of read/writes >>> (like btrfs rebalance). >>> >>> With current Linux-4.1.6 'btrfs balance' fails after ~10 minutes after >>> start. I reverted ZAC related changes and then ran rebalancing. The >>> operation finished successfully after 3 hours of running. >>> >> Can you be a bit more specific about the 'ZAC related changes'? >> There have been several patches, and we really would need to know >> which one was the offending one. >> Can you try to bisect things here? > > OK, let's stop shooting the messenger here. There are multiple reports > of this problem. The pattern seems to be some type of error causes > everything to die. > > There looks to be an obvious bug in > 9162c6579bf90b3f5ddb7e3a6c6fa946c1b4cbeb in that there's no > ATA_DEV_ZAC_UNSUP class which means that any attempt to disable the > device pushes it up to ATA_DEV_NONE. I'm not sure ... don't have time > to follow the code ... but doesn't this interfere with the speed > dropping routines which seems to disable then re-enable the device? > Does adding ATA_DEV_ZAC_UNSUP fix this problem? patch (compile tested > only) below. > > James > > --- > > diff --git a/drivers/ata/libata-transport.c b/drivers/ata/libata-transport.c > index d6c37bc..fa83320 100644 > --- a/drivers/ata/libata-transport.c > +++ b/drivers/ata/libata-transport.c > @@ -144,6 +144,7 @@ static struct { > { ATA_DEV_SEMB, "semb" }, > { ATA_DEV_SEMB_UNSUP, "semb" }, > { ATA_DEV_ZAC, "zac" }, > + { ATA_DEV_ZAC_UNSUP, "zac" }, > { ATA_DEV_NONE, "none" } > }; > ata_bitfield_name_search(class, ata_class_names) > diff --git a/include/linux/libata.h b/include/linux/libata.h > index 36ce37b..49c5b98 100644 > --- a/include/linux/libata.h > +++ b/include/linux/libata.h > @@ -191,7 +191,8 @@ enum { > ATA_DEV_SEMB = 7, /* SEMB */ > ATA_DEV_SEMB_UNSUP = 8, /* SEMB (unsupported) */ > ATA_DEV_ZAC = 9, /* ZAC device */ > - ATA_DEV_NONE = 10, /* no device */ > + ATA_DEV_ZAC_UNSUP = 10, /* ZAC (unsupported) */ > + ATA_DEV_NONE = 11, /* no device */ > > /* struct ata_link flags */ > ATA_LFLAG_NO_HRST = (1 << 1), /* avoid hardreset */ > @@ -1517,7 +1518,8 @@ static inline unsigned int ata_class_enabled(unsigned int class) > static inline unsigned int ata_class_disabled(unsigned int class) > { > return class == ATA_DEV_ATA_UNSUP || class == ATA_DEV_ATAPI_UNSUP || > - class == ATA_DEV_PMP_UNSUP || class == ATA_DEV_SEMB_UNSUP; > + class == ATA_DEV_PMP_UNSUP || class == ATA_DEV_SEMB_UNSUP || > + class == ATA_DEV_ZAC_UNSUP; > } > > static inline unsigned int ata_class_absent(unsigned int class) > > Yes, you are correct. Even if this does not fix up this particular issue it looks like a valid fix. Reviewed-by: Hannes Reinecke <hare@suse.de> Cheers, Hannes
diff --git a/drivers/ata/libata-transport.c b/drivers/ata/libata-transport.c index d6c37bc..fa83320 100644 --- a/drivers/ata/libata-transport.c +++ b/drivers/ata/libata-transport.c @@ -144,6 +144,7 @@ static struct { { ATA_DEV_SEMB, "semb" }, { ATA_DEV_SEMB_UNSUP, "semb" }, { ATA_DEV_ZAC, "zac" }, + { ATA_DEV_ZAC_UNSUP, "zac" }, { ATA_DEV_NONE, "none" } }; ata_bitfield_name_search(class, ata_class_names) diff --git a/include/linux/libata.h b/include/linux/libata.h index 36ce37b..49c5b98 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -191,7 +191,8 @@ enum { ATA_DEV_SEMB = 7, /* SEMB */ ATA_DEV_SEMB_UNSUP = 8, /* SEMB (unsupported) */ ATA_DEV_ZAC = 9, /* ZAC device */ - ATA_DEV_NONE = 10, /* no device */ + ATA_DEV_ZAC_UNSUP = 10, /* ZAC (unsupported) */ + ATA_DEV_NONE = 11, /* no device */ /* struct ata_link flags */ ATA_LFLAG_NO_HRST = (1 << 1), /* avoid hardreset */ @@ -1517,7 +1518,8 @@ static inline unsigned int ata_class_enabled(unsigned int class) static inline unsigned int ata_class_disabled(unsigned int class) { return class == ATA_DEV_ATA_UNSUP || class == ATA_DEV_ATAPI_UNSUP || - class == ATA_DEV_PMP_UNSUP || class == ATA_DEV_SEMB_UNSUP; + class == ATA_DEV_PMP_UNSUP || class == ATA_DEV_SEMB_UNSUP || + class == ATA_DEV_ZAC_UNSUP; } static inline unsigned int ata_class_absent(unsigned int class)