Commit eb36b953 authored by Peter Lieven's avatar Peter Lieven Committed by Paolo Bonzini
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarPeter Lieven <pl@kamp.de>
Message-Id: <1468831940-15556-2-git-send-email-pl@kamp.de>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e5dfc5e8

block/iscsi.c

+5 −3
Original line number Diff line number Diff line
@@ -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,