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From: Andy Grover <agrover@redhat.com>
To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Sagi Grimberg <sagig@mellanox.com>,
	"Nicholas A. Bellinger" <nab@daterainc.com>,
	target-devel <target-devel@vger.kernel.org>,
	linux-scsi <linux-scsi@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.de>,
	Or Gerlitz <ogerlitz@mellanox.com>
Subject: Re: [PATCH 07/14] target/sbc: Add P_TYPE + PROT_EN bits to READ_CAPACITY_16
Date: Fri, 10 Jan 2014 11:50:50 -0800	[thread overview]
Message-ID: <52D04F1A.2000808@redhat.com> (raw)
In-Reply-To: <1389334891.5567.373.camel@haakon3.risingtidesystems.com>

On 01/09/2014 10:21 PM, Nicholas A. Bellinger wrote:
>> What about FORMAT_UNIT emulation?
>
> Would certainly be useful to have..
>
>> The backstore protection configuration is done at the target side via
>> configfs/targetcli, if you publish DIF support in
>> INQUERY_EVPD/READ_CAPACITY you need to accept protection information format?
>
> Mmmm, these two bits bits are following what scsi_debug is currently
> exposing minus FORMAT_UNIT support..?
>
> MKP..?

Yes, don't you need FORMAT UNIT because protection information is going 
to mean the pi-enabled lun will need to report less blocks? The ramdisk 
backstore changes in this series allocate extra space for PI info, but 
my understanding was that especially for emulation with block and fileio 
backstores, everything needs to go in the same amount of space.

Furthermore, if we want PI info stored along with the blocks, then block 
and fileio backstore formats are no longer going to be 1:1 -- requiring 
offset calculations, non-aligned read-modify-write, and all that 
unpleasantness to be handled?

I've looked at the patchset and the code looks good to me, so I guess 
I'm trying to understand the scope of future work needed on the 
backstore side for this support to be functional.

Regards -- Andy


  reply	other threads:[~2014-01-10 19:51 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-08 20:15 [PATCH 00/14] target: Initial support for DIF Type1+Type3 emulation Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 01/14] target: Add DIF related base definitions Nicholas A. Bellinger
2014-01-09 10:58   ` Sagi Grimberg
2014-01-08 20:15 ` [PATCH 02/14] target: Add DIF CHECK_CONDITION ASC/ASCQ exception cases Nicholas A. Bellinger
2014-01-09 10:43   ` Sagi Grimberg
2014-01-10  6:53     ` Nicholas A. Bellinger
2014-01-14  7:44       ` Sagi Grimberg
2014-01-14  8:53         ` Nicholas A. Bellinger
2014-01-14 10:56           ` Sagi Grimberg
2014-01-08 20:15 ` [PATCH 03/14] target/sbc: Add sbc_check_prot + update sbc_parse_cdb for DIF Nicholas A. Bellinger
2014-01-09 14:58   ` Sagi Grimberg
2014-01-10  7:04     ` Nicholas A. Bellinger
2014-01-12 11:59       ` Sagi Grimberg
2014-01-13 19:23         ` Nicholas A. Bellinger
2014-01-10 20:30   ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 04/14] target/sbc: Add DIF TYPE1+TYPE3 read/write verify emulation Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 05/14] target/spc: Add protection bit to standard INQUIRY output Nicholas A. Bellinger
2014-01-10 20:34   ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 06/14] target/spc: Add protection related bits to INQUIRY EVPD=0x86 Nicholas A. Bellinger
2014-01-10 20:35   ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 07/14] target/sbc: Add P_TYPE + PROT_EN bits to READ_CAPACITY_16 Nicholas A. Bellinger
2014-01-09 10:24   ` Sagi Grimberg
2014-01-10  6:21     ` Nicholas A. Bellinger
2014-01-10 19:50       ` Andy Grover [this message]
2014-01-10 20:15         ` Nicholas A. Bellinger
2014-01-10 20:46         ` Martin K. Petersen
2014-01-12 11:49           ` Sagi Grimberg
2014-01-10 20:40       ` Martin K. Petersen
2014-01-10 20:39     ` Martin K. Petersen
2014-01-12 12:13       ` Sagi Grimberg
2014-01-12 12:33         ` Martin K. Petersen
2014-01-12 12:47           ` Sagi Grimberg
2014-01-12 12:53             ` Martin K. Petersen
2014-01-12 16:37         ` Douglas Gilbert
2014-01-12 17:21           ` Martin K. Petersen
2014-01-12 18:53             ` Douglas Gilbert
2014-01-13 16:33               ` Sagi Grimberg
2014-01-12 12:13       ` Sagi Grimberg
2014-01-10 20:37   ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 08/14] target/spc: Expose ATO bit in control mode page Nicholas A. Bellinger
2014-01-10 20:57   ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 09/14] target/configfs: Expose protection device attributes Nicholas A. Bellinger
2014-01-09 11:01   ` Sagi Grimberg
2014-01-10  7:00     ` Nicholas A. Bellinger
2014-01-12 11:56       ` Sagi Grimberg
2014-01-10 21:01   ` Martin K. Petersen
2014-01-12 12:18     ` Sagi Grimberg
2014-01-12 12:43       ` Martin K. Petersen
2014-01-12 12:52         ` Sagi Grimberg
2014-01-13 18:30     ` Nicholas A. Bellinger
2014-01-13 18:52       ` James Bottomley
2014-01-13 19:27         ` Nicholas A. Bellinger
2014-01-13 19:43           ` James Bottomley
2014-01-13 20:19           ` Martin K. Petersen
2014-01-13 20:24             ` James Bottomley
2014-01-13 20:30               ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 10/14] target: Add protection SGLs to target_submit_cmd_map_sgls Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 11/14] target/rd: Refactor rd_build_device_space + rd_release_device_space Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 12/14] target/rd: Add support for protection SGL setup + release Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 13/14] target/rd: Add DIF protection into rd_execute_rw Nicholas A. Bellinger
2014-01-09 10:32   ` Sagi Grimberg
2014-01-10  6:52     ` Nicholas A. Bellinger
2014-01-12 11:53       ` Sagi Grimberg
2014-01-13 19:22         ` Nicholas A. Bellinger
2014-01-10 21:06     ` Martin K. Petersen
2014-01-12 12:23       ` Sagi Grimberg
2014-01-08 20:15 ` [PATCH 14/14] tcm_loop: Enable DIF/DIX modes in SCSI host LLD Nicholas A. Bellinger
2014-01-10 21:09   ` Martin K. Petersen
2014-01-13 18:45     ` Nicholas A. Bellinger
2014-01-13 20:08       ` Martin K. Petersen
2014-01-10  2:00 ` [PATCH 00/14] target: Initial support for DIF Type1+Type3 emulation Martin K. Petersen
2014-01-10  5:57   ` Nicholas A. Bellinger
2014-01-15 18:03 ` sagi grimberg
2014-01-15 21:55   ` Nicholas A. Bellinger
2014-01-16  1:42     ` Martin K. Petersen
2014-01-16  2:32       ` Nicholas A. Bellinger
2014-01-16  3:04         ` Martin K. Petersen
2014-01-16  7:45       ` sagi grimberg

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