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block/iscsi: fix rounding in iscsi_allocationmap_set

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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 <pbonzini@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Message-Id: <1468831940-15556-2-git-send-email-pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Lieven 2016-07-18 10:52:19 +02:00 committed by Paolo Bonzini
parent e5dfc5e8e7
commit eb36b953e0
1 changed files with 5 additions and 3 deletions
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8
block/iscsi.c
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@ -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,