RE: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
-Original Message- From: James Bottomley [mailto:jbottom...@parallels.com] Sent: Monday, July 28, 2014 1:03 PM To: KY Srinivasan Cc: linux-ker...@vger.kernel.org; h...@infradead.org; sits...@gmail.com; de...@linuxdriverproject.org; a...@canonical.com; martin.peter...@oracle.com; linux-scsi@vger.kernel.org; oher...@suse.com; gre...@linuxfoundation.org; jasow...@redhat.com Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests On Mon, 2014-07-28 at 19:05 +, KY Srinivasan wrote: -Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Monday, July 28, 2014 12:03 PM To: KY Srinivasan Cc: Martin K. Petersen; Sitsofe Wheeler; Christoph Hellwig; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests KY == KY Srinivasan k...@microsoft.com writes: KY, KY At the time thin-provisioning was defined, the discovery KY information was first proposed in READ CAPACITY 16 command. And then KY moved into the new dedicated VPD page - B2h. You can see the KY information reported in this VPD page is richer than READ KY CAPACITY KY 16 command. As this transition happened during we added the KY feature, Windows uses the newer method that based on VPD page KY B2h. It looks Linux tries to use both new and old method which is weird to me. The READ CAPACITY(16) response is not optional. Ok; that settles the issue then. I will attempt to get it fixed on Windows. Like Martin says, this isn't optional either/or; it's mandatory to support the RC 16 bits. If you don't want to get into playing the messenger between us and the windows guys on SCSI standards, we'd be happy to communicate directly, either by email or a phone meeting. We will fix this bug in the next release of Windows; we are also looking at backporting the fix to prior versions of Windows. Thanks, K. Y
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
KY == KY Srinivasan k...@microsoft.com writes: KY We will fix this bug in the next release of Windows; we are also KY looking at backporting the fix to prior versions of Windows. Excellent. Thanks for looking into this! -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
-Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Saturday, July 26, 2014 12:25 PM To: KY Srinivasan Cc: Martin K. Petersen; Sitsofe Wheeler; Christoph Hellwig; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests KY == KY Srinivasan k...@microsoft.com writes: Great! I'd just like to have a reasonable level of confidence in what's happening down the stack before I entertain turning something on that's not being properly advertised. KY As I look at the output of inquiry between Linux on Hyper-V and KY native Linux, is not specifying conformance level the main issue? The main problem for this particular use case (aside from the issue we've already addressed) is that the passthrough device (SATA SSD) has LBPME=0 in the READ CAPACITY(16) response. The LBP VPD is correctly provided with LBPU flag set but because LBPME is reported as disabled we will not attempt to issue UNMAP commands to the device. Had a chance to chat with the Windows sscsi folks. Here is their response: At the time thin-provisioning was defined, the discovery information was first proposed in READ CAPACITY 16 command. And then moved into the new dedicated VPD page - B2h. You can see the information reported in this VPD page is richer than READ CAPACITY 16 command. As this transition happened during we added the feature, Windows uses the newer method that based on VPD page B2h. It looks Linux tries to use both new and old method which is weird to me. Would it make sense for us to work around this issue for Linux on Hyper-V (just use the VPD page instead of looking at the output of READ CAPACITY)? Regards, K. Y -- Martin K. PetersenOracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
KY == KY Srinivasan k...@microsoft.com writes: KY, KY At the time thin-provisioning was defined, the discovery KY information was first proposed in READ CAPACITY 16 command. And then KY moved into the new dedicated VPD page - B2h. You can see the KY information reported in this VPD page is richer than READ CAPACITY KY 16 command. As this transition happened during we added the feature, KY Windows uses the newer method that based on VPD page B2h. It looks KY Linux tries to use both new and old method which is weird to me. The READ CAPACITY(16) response is not optional. SBC3r36 section 4.7.3.3 Thin provisioned logical unit: The device server in a thin provisioned logical unit shall set: a) the LBPME bit to one in the READ CAPACITY (16) parameter data (see 5.16.2); and b) the PROVISIONING TYPE field to 010b (i.e., thin provisioned) in the Logical Block Provisioning VPD page (see 6.6.4). That's a shall. The LBP VPD elaborates on the provisioning type, commands preference, etc. But it's all gated by LBPME=1 in the READ CAPACITY(16) response. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
-Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Monday, July 28, 2014 12:03 PM To: KY Srinivasan Cc: Martin K. Petersen; Sitsofe Wheeler; Christoph Hellwig; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests KY == KY Srinivasan k...@microsoft.com writes: KY, KY At the time thin-provisioning was defined, the discovery KY information was first proposed in READ CAPACITY 16 command. And then KY moved into the new dedicated VPD page - B2h. You can see the KY information reported in this VPD page is richer than READ CAPACITY KY 16 command. As this transition happened during we added the feature, KY Windows uses the newer method that based on VPD page B2h. It looks KY Linux tries to use both new and old method which is weird to me. The READ CAPACITY(16) response is not optional. Ok; that settles the issue then. I will attempt to get it fixed on Windows. K. Y -- Martin K. PetersenOracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
On Mon, 2014-07-28 at 19:05 +, KY Srinivasan wrote: -Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Monday, July 28, 2014 12:03 PM To: KY Srinivasan Cc: Martin K. Petersen; Sitsofe Wheeler; Christoph Hellwig; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests KY == KY Srinivasan k...@microsoft.com writes: KY, KY At the time thin-provisioning was defined, the discovery KY information was first proposed in READ CAPACITY 16 command. And then KY moved into the new dedicated VPD page - B2h. You can see the KY information reported in this VPD page is richer than READ CAPACITY KY 16 command. As this transition happened during we added the feature, KY Windows uses the newer method that based on VPD page B2h. It looks KY Linux tries to use both new and old method which is weird to me. The READ CAPACITY(16) response is not optional. Ok; that settles the issue then. I will attempt to get it fixed on Windows. Like Martin says, this isn't optional either/or; it's mandatory to support the RC 16 bits. If you don't want to get into playing the messenger between us and the windows guys on SCSI standards, we'd be happy to communicate directly, either by email or a phone meeting. James
RE: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
-Original Message-
From: James Bottomley [mailto:jbottom...@parallels.com]
Sent: Monday, July 28, 2014 1:03 PM
To: KY Srinivasan
Cc: linux-ker...@vger.kernel.org; h...@infradead.org; sits...@gmail.com;
de...@linuxdriverproject.org; a...@canonical.com;
martin.peter...@oracle.com; linux-scsi@vger.kernel.org;
oher...@suse.com; gre...@linuxfoundation.org; jasow...@redhat.com
Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
On Mon, 2014-07-28 at 19:05 +, KY Srinivasan wrote:
-Original Message-
From: Martin K. Petersen [mailto:martin.peter...@oracle.com]
Sent: Monday, July 28, 2014 12:03 PM
To: KY Srinivasan
Cc: Martin K. Petersen; Sitsofe Wheeler; Christoph Hellwig;
gre...@linuxfoundation.org; linux-ker...@vger.kernel.org;
de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com;
jasow...@redhat.com; jbottom...@parallels.com; linux-
s...@vger.kernel.org
Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks
tests
KY == KY Srinivasan k...@microsoft.com writes:
KY,
KY At the time thin-provisioning was defined, the discovery
KY information was first proposed in READ CAPACITY 16 command. And
then
KY moved into the new dedicated VPD page - B2h. You can see the
KY information reported in this VPD page is richer than READ
KY CAPACITY
KY 16 command. As this transition happened during we added the
KY feature, Windows uses the newer method that based on VPD page
KY B2h. It looks Linux tries to use both new and old method which is
weird to me.
The READ CAPACITY(16) response is not optional.
Ok; that settles the issue then. I will attempt to get it fixed on Windows.
Like Martin says, this isn't optional either/or; it's mandatory to support
the RC
16 bits. If you don't want to get into playing the messenger between us and
the windows guys on SCSI standards, we'd be happy to communicate
directly, either by email or a phone meeting.
Thanks James. I will take up your offer if needed.
Regards,
K. Y
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RE: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
-Original Message- From: James Bottomley [mailto:jbottom...@parallels.com] Sent: Friday, July 25, 2014 10:10 AM To: KY Srinivasan Cc: linux-ker...@vger.kernel.org; h...@infradead.org; sits...@gmail.com; de...@linuxdriverproject.org; a...@canonical.com; martin.peter...@oracle.com; linux-scsi@vger.kernel.org; oher...@suse.com; gre...@linuxfoundation.org; jasow...@redhat.com Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests On Fri, 2014-07-25 at 16:47 +, KY Srinivasan wrote: -Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Thursday, July 24, 2014 8:54 AM To: Sitsofe Wheeler Cc: Martin K. Petersen; Christoph Hellwig; KY Srinivasan; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests Sitsofe == Sitsofe Wheeler sits...@gmail.com writes: Sitsofe So we can see it is really a SATA device that announces Sitsofe discard correctly and supports discard through WRITE_SAME(16). No, that's the SATA device that announces support for DSM TRIM, and as a result the Linux SATL reports support for WRITE SAME(16) w. the UNMAP bit set and LBPME. Sitsofe It is the act of passing it through Hyper-V that turned it Sitsofe into a SCSI device that supports UNMAP (but not Sitsofe WRITE_SAME(16)), doesn't announce its SCSI conformance Sitsofe number and doesn't correctly announce which features it Sitsofe supports. Surely in this case it's reasonable to quirk our way around the problem? No. That's an issue in Hyper-V that'll you'll have to take up with Microsoft. I don't know what their passthrough limitations are for SCSI- ATA translation. Maybe K. Y. has some insight into this? For the pass through case, the host validates the request and passes the request to the device. However, not all scsi commands are passed through even though the device it is being passed through may support the command. WRITE_SAME is one such command. Consequently, in the EVPD page, we will set state indicating that WRITE_SAME is not supported (even if the device supports it). I think you haven't appreciated the problem: He's passing a SATA SSD via the SCSI hyper-v interface. That means that the windows host is doing SCSI- ATA translation. The problem is that the Windows translation layer (SATL) looks to be incomplete and it's not correctly translating the IDENTIFY bit that corresponds to TRIM to the correct VPD pages so consequently, Linux won't send UNMAP commands to the device (to be translated back to TRIM). We already know this is a bug in the Windows SATL which needs fixing (if you could report it and get a fix, that would be great) and that we're not going to be able to work around this automatically in Linux because the proposed patch would have us unconditionally try UNMAP for all Hyper-V devices. The current proposed fix is to enable UNMAP manually via sysfs in the guest boot scripts, but obviously that means that Hyper-V guests with direct pass through of SSDs need operator intervention to turn on TRIM. James, Thanks for the clarification. I am talking to the folks in MSFT that develop the native scsi stack on Windows. Hyper-V's back-end driver is not involved in SATL. I will keep you guys posted. Regards, K. Y James
RE: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
-Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Friday, July 25, 2014 9:57 AM To: KY Srinivasan Cc: Martin K. Petersen; Sitsofe Wheeler; Christoph Hellwig; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests KY == KY Srinivasan k...@microsoft.com writes: KY For the pass through case, the host validates the request and passes KY the request to the device. However, not all scsi commands are KY passed through even though the device it is being passed through may KY support the command. WRITE_SAME is one such command. Consequently, KY in the EVPD page, we will set state indicating that WRITE_SAME is KY not supported (even if the device supports it). The LBP VPD page flags UNMAP as being supported. Do you actually support UNMAP to DSM TRIM SCSI-ATA translation? Martin, I have been told by the Windows folks that this is done. I am trying to get additional details. K. Y One challenge in that department is that a single UNMAP command may turn into many, many, many DSM TRIM commands on the underlying SATA device. That's why we went with WRITE SAME for the internal Linux SATL, capping the maximum number of blocks to what we can fit in a single DSM TRIM command. -- Martin K. PetersenOracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
KY == KY Srinivasan k...@microsoft.com writes: The LBP VPD page flags UNMAP as being supported. Do you actually support UNMAP to DSM TRIM SCSI-ATA translation? KY I have been told by the Windows folks that this is done. I am trying KY to get additional details. Great! I'd just like to have a reasonable level of confidence in what's happening down the stack before I entertain turning something on that's not being properly advertised. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
-Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Saturday, July 26, 2014 9:55 AM To: KY Srinivasan Cc: Martin K. Petersen; Sitsofe Wheeler; Christoph Hellwig; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests KY == KY Srinivasan k...@microsoft.com writes: The LBP VPD page flags UNMAP as being supported. Do you actually support UNMAP to DSM TRIM SCSI-ATA translation? KY I have been told by the Windows folks that this is done. I am trying KY to get additional details. Great! I'd just like to have a reasonable level of confidence in what's happening down the stack before I entertain turning something on that's not being properly advertised. As I look at the output of inquiry between Linux on Hyper-V and native Linux, is not specifying conformance level the main issue? K. Y -- Martin K. PetersenOracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
-Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Saturday, July 26, 2014 12:25 PM To: KY Srinivasan Cc: Martin K. Petersen; Sitsofe Wheeler; Christoph Hellwig; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests KY == KY Srinivasan k...@microsoft.com writes: Great! I'd just like to have a reasonable level of confidence in what's happening down the stack before I entertain turning something on that's not being properly advertised. KY As I look at the output of inquiry between Linux on Hyper-V and KY native Linux, is not specifying conformance level the main issue? The main problem for this particular use case (aside from the issue we've already addressed) is that the passthrough device (SATA SSD) has LBPME=0 in the READ CAPACITY(16) response. The LBP VPD is correctly provided with LBPU flag set but because LBPME is reported as disabled we will not attempt to issue UNMAP commands to the device. Oh; ok. I missed the read_capacity response. Thanks, K. Y -- Martin K. PetersenOracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
-Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Thursday, July 24, 2014 8:54 AM To: Sitsofe Wheeler Cc: Martin K. Petersen; Christoph Hellwig; KY Srinivasan; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests Sitsofe == Sitsofe Wheeler sits...@gmail.com writes: Sitsofe So we can see it is really a SATA device that announces discard Sitsofe correctly and supports discard through WRITE_SAME(16). No, that's the SATA device that announces support for DSM TRIM, and as a result the Linux SATL reports support for WRITE SAME(16) w. the UNMAP bit set and LBPME. Sitsofe It is the act of passing it through Hyper-V that turned it into Sitsofe a SCSI device that supports UNMAP (but not WRITE_SAME(16)), Sitsofe doesn't announce its SCSI conformance number and doesn't Sitsofe correctly announce which features it supports. Surely in this Sitsofe case it's reasonable to quirk our way around the problem? No. That's an issue in Hyper-V that'll you'll have to take up with Microsoft. I don't know what their passthrough limitations are for SCSI-ATA translation. Maybe K. Y. has some insight into this? For the pass through case, the host validates the request and passes the request to the device. However, not all scsi commands are passed through even though the device it is being passed through may support the command. WRITE_SAME is one such command. Consequently, in the EVPD page, we will set state indicating that WRITE_SAME is not supported (even if the device supports it). Hope this helps. K. Y There must be a reason why the VPD page was added and yet the device not flagged as LBPME=1. Many vendors do not support UNMAP/WRITE SAME to DSM TRIM translation. Additionally, many vendors explicitly only whitelist drives that are known to be working correctly. Your drive is an ADATA and therefore very likely to be blacklisted by default by a vendor SATL. -- Martin K. PetersenOracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
KY == KY Srinivasan k...@microsoft.com writes: KY For the pass through case, the host validates the request and passes KY the request to the device. However, not all scsi commands are KY passed through even though the device it is being passed through may KY support the command. WRITE_SAME is one such command. Consequently, KY in the EVPD page, we will set state indicating that WRITE_SAME is KY not supported (even if the device supports it). The LBP VPD page flags UNMAP as being supported. Do you actually support UNMAP to DSM TRIM SCSI-ATA translation? One challenge in that department is that a single UNMAP command may turn into many, many, many DSM TRIM commands on the underlying SATA device. That's why we went with WRITE SAME for the internal Linux SATL, capping the maximum number of blocks to what we can fit in a single DSM TRIM command. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
On Fri, 2014-07-25 at 16:47 +, KY Srinivasan wrote: -Original Message- From: Martin K. Petersen [mailto:martin.peter...@oracle.com] Sent: Thursday, July 24, 2014 8:54 AM To: Sitsofe Wheeler Cc: Martin K. Petersen; Christoph Hellwig; KY Srinivasan; gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com; a...@canonical.com; jasow...@redhat.com; jbottom...@parallels.com; linux- s...@vger.kernel.org Subject: Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests Sitsofe == Sitsofe Wheeler sits...@gmail.com writes: Sitsofe So we can see it is really a SATA device that announces discard Sitsofe correctly and supports discard through WRITE_SAME(16). No, that's the SATA device that announces support for DSM TRIM, and as a result the Linux SATL reports support for WRITE SAME(16) w. the UNMAP bit set and LBPME. Sitsofe It is the act of passing it through Hyper-V that turned it into Sitsofe a SCSI device that supports UNMAP (but not WRITE_SAME(16)), Sitsofe doesn't announce its SCSI conformance number and doesn't Sitsofe correctly announce which features it supports. Surely in this Sitsofe case it's reasonable to quirk our way around the problem? No. That's an issue in Hyper-V that'll you'll have to take up with Microsoft. I don't know what their passthrough limitations are for SCSI-ATA translation. Maybe K. Y. has some insight into this? For the pass through case, the host validates the request and passes the request to the device. However, not all scsi commands are passed through even though the device it is being passed through may support the command. WRITE_SAME is one such command. Consequently, in the EVPD page, we will set state indicating that WRITE_SAME is not supported (even if the device supports it). I think you haven't appreciated the problem: He's passing a SATA SSD via the SCSI hyper-v interface. That means that the windows host is doing SCSI-ATA translation. The problem is that the Windows translation layer (SATL) looks to be incomplete and it's not correctly translating the IDENTIFY bit that corresponds to TRIM to the correct VPD pages so consequently, Linux won't send UNMAP commands to the device (to be translated back to TRIM). We already know this is a bug in the Windows SATL which needs fixing (if you could report it and get a fix, that would be great) and that we're not going to be able to work around this automatically in Linux because the proposed patch would have us unconditionally try UNMAP for all Hyper-V devices. The current proposed fix is to enable UNMAP manually via sysfs in the guest boot scripts, but obviously that means that Hyper-V guests with direct pass through of SSDs need operator intervention to turn on TRIM. James
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
Sitsofe == Sitsofe Wheeler sits...@gmail.com writes: Sitsofe Fix incorrectly named variable. Some block devices (such as Sitsofe Hyper-V passthrough SSDs) support logical block provisioning Sitsofe (e.g. via UNMAP) but don't set lbpme thus disabling discard. The fix for an SSD that is known to support LBP but which does not claim support for it is to use: echo unmap /sys/class/scsi_disk/foo/provisioning_mode I'm very much against short-circuiting the LBP logic in a passthrough driver because then we might end up in the exact situation we were trying to avoid with this patch series. Namely sending down commands unsupported by the target device. This kind of thing really needs to be a sysadmin decision and can be handled with a udev rule. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
On Thu, Jul 24, 2014 at 09:54:24AM -0400, Martin K. Petersen wrote: I'm very much against short-circuiting the LBP logic in a passthrough driver because then we might end up in the exact situation we were trying to avoid with this patch series. Namely sending down commands unsupported by the target device. This kind of thing really needs to be a sysadmin decision and can be handled with a udev rule. I agree - I'd like to pull in KY's simple fix as soon as I get a second review for it. -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
On Thu, Jul 24, 2014 at 08:34:19AM -0700, Christoph Hellwig wrote: I agree - I'd like to pull in KY's simple fix as soon as I get a second review for it. Ok, looks like I just got that from Hannes. Let's see if there's more to be done for the pass through case, but I'd rather wait for the next window for that. -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
On Thu, Jul 24, 2014 at 09:54:24AM -0400, Martin K. Petersen wrote: Sitsofe == Sitsofe Wheeler sits...@gmail.com writes: Sitsofe Fix incorrectly named variable. Some block devices (such as Sitsofe Hyper-V passthrough SSDs) support logical block provisioning Sitsofe (e.g. via UNMAP) but don't set lbpme thus disabling discard. The fix for an SSD that is known to support LBP but which does not claim support for it is to use: echo unmap /sys/class/scsi_disk/foo/provisioning_mode I'm very much against short-circuiting the LBP logic in a passthrough driver because then we might end up in the exact situation we were trying to avoid with this patch series. Namely sending down commands unsupported by the target device. This kind of thing really needs to be a sysadmin decision and can be handled with a udev rule. The problem is that the SSD _does_ claim to support it. Here are the results of booting Linux directly on the host hardware and looking at the device directly with a 3.10.35 kernel: root@sysresccd /root % uname -a Linux sysresccd 3.10.35-std420-amd64 #2 SMP Wed Apr 2 18:31:51 UTC 2014 x86_64 Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz GenuineIntel GNU/Linux root@sysresccd /root % sg_vpd -p lbpv /dev/sdb root@sysresccd /root % sg_inq /dev/sdb standard INQUIRY: PQual=0 Device_type=0 RMB=0 version=0x05 [SPC-3] [AERC=0] [TrmTsk=0] NormACA=0 HiSUP=0 Resp_data_format=2 SCCS=0 ACC=0 TPGS=0 3PC=0 Protect=0 [BQue=0] EncServ=0 MultiP=0 [MChngr=0] [ACKREQQ=0] Addr16=0 [RelAdr=0] WBus16=0 Sync=0 Linked=0 [TranDis=0] CmdQue=0 [SPI: Clocking=0x0 QAS=0 IUS=0] length=96 (0x60) Peripheral device type: disk Vendor identification: ATA Product identification: ADATA SSD S510 1 Product revision level: 5.2. Unit serial number: 0320511550032076 root@sysresccd /root % sg_readcap -l /dev/sdb Read Capacity results: Protection: prot_en=0, p_type=0, p_i_exponent=0 Logical block provisioning: lbpme=1, lbprz=0 Last logical block address=234441647 (0xdf94baf), Number of logical blocks=234441648 Logical block length=512 bytes Logical blocks per physical block exponent=0 Lowest aligned logical block address=0 Hence: Device size: 120034123776 bytes, 114473.5 MiB, 120.03 GB Logical block provisioning VPD page (SBC): Unmap command supported (LBPU): 0 Write same (16) with unmap bit supported (LBWS): 1 Write same (10) with unmap bit supported (LBWS10): 0 Logical block provisioning read zeros (LBPRZ): 0 Anchored LBAs supported (ANC_SUP): 0 Threshold exponent: 0 Descriptor present (DP): 0 Provisioning type: 0 root@sysresccd /root % sg_vpd -p bl /dev/sdb Block limits VPD page (SBC): Write same no zero (WSNZ): 0 Maximum compare and write length: 0 blocks Optimal transfer length granularity: 1 blocks Maximum transfer length: 0 blocks Optimal transfer length: 0 blocks Maximum prefetch length: 0 blocks Maximum unmap LBA count: 0 Maximum unmap block descriptor count: 0 Optimal unmap granularity: 1 Unmap granularity alignment valid: 0 Unmap granularity alignment: 0 Maximum write same length: 0x3fffc0 blocks root@sysresccd /root % grep . /sys/block/sdb/device/scsi_disk/1:0:0:0/* /sys/block/sdb/device/scsi_disk/1:0:0:0/allow_restart:1 /sys/block/sdb/device/scsi_disk/1:0:0:0/app_tag_own:0 /sys/block/sdb/device/scsi_disk/1:0:0:0/cache_type:write back grep: /sys/block/sdb/device/scsi_disk/1:0:0:0/device: Is a directory /sys/block/sdb/device/scsi_disk/1:0:0:0/FUA:0 /sys/block/sdb/device/scsi_disk/1:0:0:0/manage_start_stop:1 /sys/block/sdb/device/scsi_disk/1:0:0:0/max_medium_access_timeouts:2 /sys/block/sdb/device/scsi_disk/1:0:0:0/max_write_same_blocks:0 grep: /sys/block/sdb/device/scsi_disk/1:0:0:0/power: Is a directory /sys/block/sdb/device/scsi_disk/1:0:0:0/protection_mode:none /sys/block/sdb/device/scsi_disk/1:0:0:0/protection_type:0 /sys/block/sdb/device/scsi_disk/1:0:0:0/provisioning_mode:writesame_16 grep: /sys/block/sdb/device/scsi_disk/1:0:0:0/subsystem: Is a directory /sys/block/sdb/device/scsi_disk/1:0:0:0/thin_provisioning:1 So we can see it is really a SATA device that announces discard correctly and supports discard through WRITE_SAME(16). It is the act of passing it through Hyper-V that turned it into a SCSI device that supports UNMAP (but not WRITE_SAME(16)), doesn't announce its SCSI conformance number and doesn't correctly announce which features it supports. Surely in this case it's reasonable to quirk our way around the problem? -- Sitsofe | http://sucs.org/~sits/ -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
Sitsofe == Sitsofe Wheeler sits...@gmail.com writes: Sitsofe So we can see it is really a SATA device that announces discard Sitsofe correctly and supports discard through WRITE_SAME(16). No, that's the SATA device that announces support for DSM TRIM, and as a result the Linux SATL reports support for WRITE SAME(16) w. the UNMAP bit set and LBPME. Sitsofe It is the act of passing it through Hyper-V that turned it into Sitsofe a SCSI device that supports UNMAP (but not WRITE_SAME(16)), Sitsofe doesn't announce its SCSI conformance number and doesn't Sitsofe correctly announce which features it supports. Surely in this Sitsofe case it's reasonable to quirk our way around the problem? No. That's an issue in Hyper-V that'll you'll have to take up with Microsoft. I don't know what their passthrough limitations are for SCSI-ATA translation. Maybe K. Y. has some insight into this? There must be a reason why the VPD page was added and yet the device not flagged as LBPME=1. Many vendors do not support UNMAP/WRITE SAME to DSM TRIM translation. Additionally, many vendors explicitly only whitelist drives that are known to be working correctly. Your drive is an ADATA and therefore very likely to be blacklisted by default by a vendor SATL. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 3/3] [SCSI] Make LBP quirk skip lbpme checks tests
On Thu, Jul 24, 2014 at 08:35:13AM -0700, Christoph Hellwig wrote: On Thu, Jul 24, 2014 at 08:34:19AM -0700, Christoph Hellwig wrote: I agree - I'd like to pull in KY's simple fix as soon as I get a second review for it. Ok, looks like I just got that from Hannes. Let's see if there's more to be done for the pass through case, but I'd rather wait for the next window for that. There's nothing Linux can do for today's Hyper-V passthrough wrt to automatically turning on discard on my SATA SSD. Martin explained that vendors often disable UNMAP/WRITE SAME to DSM TRIM translation on purpose and/or have explicit device whitelists/blacklists for those devices they want to support. It could be that Microsoft are doing something similar (although it might be interesting to know how a Windows 2012 guest on Hyper-V handles things). -- Sitsofe | http://sucs.org/~sits/ -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
