Commit 135b9088 authored Aug 17, 2012 by Ronnie Sahlberg Committed by Paolo Bonzini Aug 28, 2012

iscsi: Set number of blocks to 0 for blank CDROM devices



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 <ronniesahlberg@gmail.com>

parent 0f1da449

block/iscsi.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -721,7 +721,12 @@ iscsi_readcapacity10_cb(struct iscsi_context *iscsi, int status,
		}

		itask->iscsilun->block_size = rc10->block_size;
		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 ;