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Re: [Qemu-devel] [PATCH 1/2] ISCSI: Set number of blocks to 0 for blank
From: |
ronnie sahlberg |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] ISCSI: Set number of blocks to 0 for blank CDROM devices |
Date: |
Sun, 19 Aug 2012 08:06:08 +1000 |
On Sun, Aug 19, 2012 at 7:57 AM, Paolo Bonzini <address@hidden> wrote:
> Il 17/08/2012 04:36, Ronnie Sahlberg ha scritto:
>> The number of blocks of the device is used to compute the device size
>> in bdrv_getlength()/iscsi_getlength().
>> For MMC devices, the ReturnedLogicalBlockAddress in the READCAPACITY10
>> has a special meaning when it is 0.
>> In this case it does not mean that LBA 0 is the last accessible LBA,
>> and thus the device has 1 readable block, but instead it means that the
>> disc is blank and there are no readable blocks.
>>
>> This change ensures that when the iSCSI LUN is loaded with a blank
>> DVD-R disk or similar that bdrv_getlength() will return the correct
>> size of the device as 0 bytes.
>>
>> Signed-off-by: Ronnie Sahlberg <address@hidden>
>> ---
>> block/iscsi.c | 7 ++++++-
>> 1 files changed, 6 insertions(+), 1 deletions(-)
>>
>> diff --git a/block/iscsi.c b/block/iscsi.c
>> index bb9cf82..fb420ea 100644
>> --- a/block/iscsi.c
>> +++ b/block/iscsi.c
>> @@ -717,7 +717,12 @@ iscsi_readcapacity10_cb(struct iscsi_context *iscsi,
>> int status,
>> }
>>
>> itask->iscsilun->block_size = rc10->block_size;
>> - itask->iscsilun->num_blocks = rc10->lba + 1;
>> + if (rc10->lba == 0) {
>> + /* blank disk loaded */
>> + itask->iscsilun->num_blocks = 0;
>> + } else {
>> + itask->iscsilun->num_blocks = rc10->lba + 1;
>> + }
>> itask->bs->total_sectors = itask->iscsilun->num_blocks *
>> itask->iscsilun->block_size /
>> BDRV_SECTOR_SIZE ;
>>
>>
>
> Thanks, applied to SCSI branch. We'll see whether this hits 1.2.
This patch only matters for the use case of having empty/blank media
loaded into an iscsi cdrom.
I doubt being able to "burn" data to an iscsi drive is very important or urgent,
so it is fine with me to delay until post 1.2
regards
ronnie sahlberg
- [Qemu-devel] [PATCH] Two trivial patches for iSCSI and blank DVDs, Ronnie Sahlberg, 2012/08/16
- [Qemu-devel] [PATCH 1/2] ISCSI: Set number of blocks to 0 for blank CDROM devices, Ronnie Sahlberg, 2012/08/16
- [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, Ronnie Sahlberg, 2012/08/16
- Re: [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, Blue Swirl, 2012/08/18
- Re: [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, Paolo Bonzini, 2012/08/18
- Re: [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, ronnie sahlberg, 2012/08/18
- Re: [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, ronnie sahlberg, 2012/08/18
- Re: [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, Paolo Bonzini, 2012/08/18
- Re: [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, ronnie sahlberg, 2012/08/18
- Re: [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, Paolo Bonzini, 2012/08/18
- Re: [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, Paolo Bonzini, 2012/08/18
- Re: [Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks, ronnie sahlberg, 2012/08/18