From eb36b953e0ebf4129b188a241fbc367062ac2e06 Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Mon, 18 Jul 2016 10:52:19 +0200 Subject: [PATCH] block/iscsi: fix rounding in iscsi_allocationmap_set when setting clusters as alloacted the boundaries have to be expanded. As Paolo pointed out the calculation of the number of clusters is wrong: Suppose cluster_sectors is 2, sector_num = 1, nb_sectors = 6: In the "mark allocated" case, you want to set 0..8, i.e. cluster_num=0, nb_clusters=4. 0--.--2--.--4--.--6--.--8 <--|_________________|--> (<--> = expanded) Instead you are setting nb_clusters=3, so that 6..8 is not marked. 0--.--2--.--4--.--6--.--8 <--|______________|!!! (! = wrong) Cc: qemu-stable@nongnu.org Reported-by: Paolo Bonzini Signed-off-by: Peter Lieven Message-Id: <1468831940-15556-2-git-send-email-pl@kamp.de> Signed-off-by: Paolo Bonzini --- block/iscsi.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/block/iscsi.c b/block/iscsi.c index cf1e9e7f66..22330e1fe0 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -432,12 +432,14 @@ static unsigned long *iscsi_allocationmap_init(IscsiLun *iscsilun) static void iscsi_allocationmap_set(IscsiLun *iscsilun, int64_t sector_num, int nb_sectors) { + int64_t cluster_num, nb_clusters; if (iscsilun->allocationmap == NULL) { return; } - bitmap_set(iscsilun->allocationmap, - sector_num / iscsilun->cluster_sectors, - DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); + cluster_num = sector_num / iscsilun->cluster_sectors; + nb_clusters = DIV_ROUND_UP(sector_num + nb_sectors, + iscsilun->cluster_sectors) - cluster_num; + bitmap_set(iscsilun->allocationmap, cluster_num, nb_clusters); } static void iscsi_allocationmap_clear(IscsiLun *iscsilun, int64_t sector_num,