From: "Martin K. Petersen" Subject: Re: [PATCH, RFC] Don't do page stablization if !CONFIG_BLKDEV_INTEGRITY Date: Wed, 07 Mar 2012 22:45:06 -0500 Message-ID: References: <4F57FC14.5090207@panasas.com> Mime-Version: 1.0 Content-Type: text/plain Cc: "Theodore Ts'o" , , To: Boaz Harrosh Return-path: Received: from rcsinet15.oracle.com ([148.87.113.117]:51457 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754748Ab2CHDpO (ORCPT ); Wed, 7 Mar 2012 22:45:14 -0500 In-Reply-To: <4F57FC14.5090207@panasas.com> (Boaz Harrosh's message of "Wed, 7 Mar 2012 16:23:48 -0800") Sender: linux-ext4-owner@vger.kernel.org List-ID: >>>>> "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: 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 {