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 <pbonz...@redhat.com>
Signed-off-by: Peter Lieven <p...@kamp.de>
---
block/iscsi.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/block/iscsi.c b/block/iscsi.c
index 93fee6d..75d6b87 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -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;
}
--
1.7.9.5
