From: Peter Lieven <pl@kamp.de>
Date: Wed, 27 Nov 2013 10:07:03 +0000 (+0100)
Subject: block/iscsi: set bdi->cluster_size
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1c0704a556dbb004a3b82791779760f418053951;p=qemu.git

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>
---

diff --git a/block/iscsi.c b/block/iscsi.c
index 93fee6d1df..75d6b875e4 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;
 }