block/iscsi: set bdi->cluster_size

this patch aims to set bdi->cluster_size to the internal page size
of the iscsi target so that enabled callers can align requests
properly.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Peter Lieven 2013-11-27 11:07:03 +01:00 committed by Stefan Hajnoczi
parent 049b09825f
commit 1c0704a556
1 changed files with 7 additions and 0 deletions

View File

@ -1580,6 +1580,13 @@ static int iscsi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
IscsiLun *iscsilun = bs->opaque;
bdi->unallocated_blocks_are_zero = !!iscsilun->lbprz;
bdi->can_write_zeroes_with_unmap = iscsilun->lbprz && iscsilun->lbp.lbpws;
/* Guess the internal cluster (page) size of the iscsi target by the means
* of opt_unmap_gran. Transfer the unmap granularity only if it has a
* reasonable size for bdi->cluster_size */
if (iscsilun->bl.opt_unmap_gran * iscsilun->block_size >= 64 * 1024 &&
iscsilun->bl.opt_unmap_gran * iscsilun->block_size <= 16 * 1024 * 1024) {
bdi->cluster_size = iscsilun->bl.opt_unmap_gran * iscsilun->block_size;
}
return 0;
}