Re: [Qemu-devel] [PATCH] ISCSI: Add support for thin-provisioning via discard/UNMAP and bigger LUNs
Il 24/04/2012 08:29, Ronnie Sahlberg ha scritto: +itask-bs-total_sectors= rc16-returned_lba * + rc16-block_length / BDRV_SECTOR_SIZE ; Ronnie, does this need to be (rc16-returned_lba + 1) * ...? READ CAPACITY returns the highest valid LBA, not the size. Please send a patch to fix this up if that's the case. Paolo
Re: [Qemu-devel] [PATCH] ISCSI: Add support for thin-provisioning via discard/UNMAP and bigger LUNs
On Fri, May 4, 2012 at 6:06 PM, Paolo Bonzini pbonz...@redhat.com wrote: Il 24/04/2012 08:29, Ronnie Sahlberg ha scritto: + itask-bs-total_sectors = rc16-returned_lba * + rc16-block_length / BDRV_SECTOR_SIZE ; Ronnie, does this need to be (rc16-returned_lba + 1) * ...? READ CAPACITY returns the highest valid LBA, not the size. Please send a patch to fix this up if that's the case. Absolutely. A patch is on its way. This is probably the third time I have made the same mistake of RC10/16 returns the lba of last block, not the number of blocks. I think READCAPACITY is just not compatible with my brain here. regards ronnie sahlberg
Re: [Qemu-devel] [PATCH] ISCSI: Add support for thin-provisioning via discard/UNMAP and bigger LUNs
Il 24/04/2012 08:29, Ronnie Sahlberg ha scritto: Update the configure test for libiscsi support to detect version 1.3 or later. Version 1.3 of libiscsi provides both READCAPACITY16 as well as UNMAP commands. Update the iscsi block layer to use READCAPACITY16 to detect the size of the LUN instead of READCAPACITY10. This allows support for LUNs larger than 2TB. Update to implement bdrv_aio_discard() using the UNMAP command. This allows us to use thin-provisioned LUNs from TGTD and other iSCSI targets that support thin-provisioning. Looks good. Kevin, do you want me to take libiscsi patches via the SCSI tree? As an aside, I am not really sure of the utility of adding these utility functions directly in libiscsi, rather than making it a pure transport library. block/iscsi.c is going to grow as you add more functionality (e.g. WRITE SAME commands), and libiscsi will have to be updated each time in lockstep. I can see the value of basic read/write/flush and readcap10/16, but with unmap it's starting to be a bit more specific. Are there other clients of libiscsi that use these functions? Should they be placed into block/iscsi.c or a new block/iscsi-cdb.c instead? Paolo
Re: [Qemu-devel] [PATCH] ISCSI: Add support for thin-provisioning via discard/UNMAP and bigger LUNs
On Tue, Apr 24, 2012 at 4:46 PM, Paolo Bonzini pbonz...@redhat.com wrote: Il 24/04/2012 08:29, Ronnie Sahlberg ha scritto: Update the configure test for libiscsi support to detect version 1.3 or later. Version 1.3 of libiscsi provides both READCAPACITY16 as well as UNMAP commands. Update the iscsi block layer to use READCAPACITY16 to detect the size of the LUN instead of READCAPACITY10. This allows support for LUNs larger than 2TB. Update to implement bdrv_aio_discard() using the UNMAP command. This allows us to use thin-provisioned LUNs from TGTD and other iSCSI targets that support thin-provisioning. Looks good. Kevin, do you want me to take libiscsi patches via the SCSI tree? As an aside, I am not really sure of the utility of adding these utility functions directly in libiscsi, rather than making it a pure transport library. block/iscsi.c is going to grow as you add more functionality (e.g. WRITE SAME commands), and libiscsi will have to be updated each time in lockstep. I can see the value of basic read/write/flush and readcap10/16, but with unmap it's starting to be a bit more specific. Are there other clients of libiscsi that use these functions? Should they be placed into block/iscsi.c or a new block/iscsi-cdb.c instead? I see your point. I like to add scsi commands as I use them to libiscsi, since then I dont have to re-write the marshalling/unmarshalling code everytime in my small test and utility programs. For example when i want to write some one-off small tools to test something. But, yes. There is no real need to use them directly from qemu. So ignore this patch for now. I will redo UNMAP in the patch to instead use the generic scsi function inside libiscsi. That will serve the purpose to verify that the public API in libiscsi is sufficient for accessing the generic transport and secondly that will show a useful example on how to send CDB+data to and to receive data back from the generic function. This generic API would be what a future virt-scsi-libiscsi integration would use anyway. regards ronnie sahlberg
Re: [Qemu-devel] [PATCH] ISCSI: Add support for thin-provisioning via discard/UNMAP and bigger LUNs
Am 24.04.2012 08:46, schrieb Paolo Bonzini: Il 24/04/2012 08:29, Ronnie Sahlberg ha scritto: Update the configure test for libiscsi support to detect version 1.3 or later. Version 1.3 of libiscsi provides both READCAPACITY16 as well as UNMAP commands. Update the iscsi block layer to use READCAPACITY16 to detect the size of the LUN instead of READCAPACITY10. This allows support for LUNs larger than 2TB. Update to implement bdrv_aio_discard() using the UNMAP command. This allows us to use thin-provisioned LUNs from TGTD and other iSCSI targets that support thin-provisioning. Looks good. Kevin, do you want me to take libiscsi patches via the SCSI tree? Sure, if you like, go ahead. Feel free to update MAINTAINERS as well. As an aside, I am not really sure of the utility of adding these utility functions directly in libiscsi, rather than making it a pure transport library. block/iscsi.c is going to grow as you add more functionality (e.g. WRITE SAME commands), and libiscsi will have to be updated each time in lockstep. I can see the value of basic read/write/flush and readcap10/16, but with unmap it's starting to be a bit more specific. Are there other clients of libiscsi that use these functions? Should they be placed into block/iscsi.c or a new block/iscsi-cdb.c instead? I think I agree. For the more obscure commands, the qemu driver should probably build the CDB on its own and use a generic function. Kevin
Re: [Qemu-devel] [PATCH] ISCSI: Add support for thin-provisioning via discard/UNMAP and bigger LUNs
Il 24/04/2012 10:02, ronnie sahlberg ha scritto: So ignore this patch for now. I will redo UNMAP in the patch to instead use the generic scsi function inside libiscsi. That will serve the purpose to verify that the public API in libiscsi is sufficient for accessing the generic transport and secondly that will show a useful example on how to send CDB+data to and to receive data back from the generic function. This generic API would be what a future virt-scsi-libiscsi integration would use anyway. I will be on holiday from tomorrow to May 1, and I won't be able to send a pull request today. As I want to minimize the time I spend looking at qemu-devel, :) I'll take this patch as is, since the new libiscsi version is needed anyway for READ CAPACITY (16). You could write a follow-up patch to teach iscsi.c about WRITE SAME(10) and WRITE SAME(16) with the unmap bit set, and use generic CDB+data functions for those. Paolo
