From: Boaz Harrosh Subject: Re: [PATCH, RFC] Don't do page stablization if !CONFIG_BLKDEV_INTEGRITY Date: Wed, 7 Mar 2012 20:37:54 -0800 Message-ID: <4F5837A2.8000306@panasas.com> References: <4F57FC14.5090207@panasas.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "Theodore Ts'o" , , To: "Martin K. Petersen" Return-path: In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On 03/07/2012 07:45 PM, Martin K. Petersen wrote: >>>>>> "Boaz" == Boaz Harrosh writes: > > Boaz> As I stated many times before, the device should have a property > Boaz> that says if it needs stable pages or not. The candidates for > Boaz> stable pages are: > > Boaz> - DIF/DIX enabled devices > Boaz> - RAID-1/4/5/6 devices > Boaz> - iscsi devices with data digest signature > Boaz> - Any other checksum enabled block device. > > Boaz> A fedora distro will have CONFIG_BLKDEV_INTEGRITY set then you are > Boaz> always out of luck, even with devices that can care less. > > Boaz> Please submit a proper patch, even a temporary mount option. But > Boaz> this is ABI. The best is to find where to export it as part of the > Boaz> device's properties sysfs dir. > > We could do something like this: > Yes, this one is perfect. Combined with Darrick's patch to actually inspect the flag at the filesystem level is the solution I want. When submitted I will also send a patch to set .needs_stable_pages in iscsi when needed. Thanks, Martin Boaz > diff --git a/block/blk-settings.c b/block/blk-settings.c > index 5680b91..442a0df 100644 > --- a/block/blk-settings.c > +++ b/block/blk-settings.c > @@ -125,6 +125,7 @@ void blk_set_default_limits(struct queue_limits *lim) > lim->io_opt = 0; > lim->misaligned = 0; > lim->cluster = 1; > + lim->needs_stable_pages = false; > } > EXPORT_SYMBOL(blk_set_default_limits); > > @@ -571,6 +572,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, > t->cluster &= b->cluster; > t->discard_zeroes_data &= b->discard_zeroes_data; > > + t->needs_stable_pages &= b->needs_stable_pages; > + > /* Physical block size a multiple of the logical block size? */ > if (t->physical_block_size & (t->logical_block_size - 1)) { > t->physical_block_size = t->logical_block_size; > diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c > index 5b85d91..d464aca 100644 > --- a/block/blk-sysfs.c > +++ b/block/blk-sysfs.c > @@ -161,6 +161,11 @@ static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *pag > return queue_var_show(queue_discard_zeroes_data(q), page); > } > > +static ssize_t queue_needs_stable_pages_show(struct request_queue *q, char *page) > +{ > + return queue_var_show(q->limits.needs_stable_pages, page); > +} > + > static ssize_t queue_write_same_max_show(struct request_queue *q, char *page) > { > return sprintf(page, "%llu\n", > @@ -364,6 +369,11 @@ static struct queue_sysfs_entry queue_discard_zeroes_data_entry = { > .show = queue_discard_zeroes_data_show, > }; > > +static struct queue_sysfs_entry queue_needs_stable_pages_entry = { > + .attr = {.name = "needs_stable_pages", .mode = S_IRUGO }, > + .show = queue_needs_stable_pages_show, > +}; > + > static struct queue_sysfs_entry queue_write_same_max_entry = { > .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO }, > .show = queue_write_same_max_show, > @@ -416,6 +426,7 @@ static struct attribute *default_attrs[] = { > &queue_discard_granularity_entry.attr, > &queue_discard_max_entry.attr, > &queue_discard_zeroes_data_entry.attr, > + &queue_needs_stable_pages_entry.attr, > &queue_write_same_max_entry.attr, > &queue_nonrot_entry.attr, > &queue_nomerges_entry.attr, > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 26eff46..146bed4 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -1752,10 +1752,11 @@ static void sd_read_protection_type(struct scsi_disk *sdkp, unsigned char *buffe > return; > } > > - if (scsi_host_dif_capable(sdp->host, type)) > + if (scsi_host_dif_capable(sdp->host, type)) { > sd_printk(KERN_NOTICE, sdkp, > "Enabling DIF Type %u protection\n", type); > - else > + sdkp->disk->queue->limits.needs_stable_pages = true; > + } else > sd_printk(KERN_NOTICE, sdkp, > "Disabling DIF Type %u protection\n", type); > } > diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c > index 0cb39ff..9dc330c 100644 > --- a/drivers/scsi/sd_dif.c > +++ b/drivers/scsi/sd_dif.c > @@ -338,6 +338,8 @@ void sd_dif_config_host(struct scsi_disk *sdkp) > sd_printk(KERN_NOTICE, sdkp, > "Enabling DIX %s protection\n", disk->integrity->name); > > + disk->queue->limits.needs_stable_pages = true; > + > /* Signal to block layer that we support sector tagging */ > if (dif && type && sdkp->ATO) { > if (type == SD_DIF_TYPE3_PROTECTION) > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index 92956b7..a5a33db 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -266,6 +266,8 @@ struct queue_limits { > unsigned char discard_misaligned; > unsigned char cluster; > unsigned char discard_zeroes_data; > + > + bool needs_stable_pages; > }; > > struct request_queue {