Commit 1da45e0c authored by Peter Lieven's avatar Peter Lieven Committed by Paolo Bonzini

block/iscsi: avoid data corruption with cache=writeback

nb_cls_shrunk in iscsi_allocmap_update can become -1 if the
request starts and ends within the same cluster. This results
in passing -1 to bitmap_set and bitmap_clear and they don't
handle negative values properly. In the end this leads to data
corruption.

Fixes: e1123a3b
Cc: qemu-stable@nongnu.org
Signed-off-by: 's avatarPeter Lieven <pl@kamp.de>
Message-Id: <1484579832-18589-1-git-send-email-pl@kamp.de>
Reviewed-by: 's avatarFam Zheng <famz@redhat.com>
Signed-off-by: 's avatarPaolo Bonzini <pbonzini@redhat.com>
parent b8bab8eb
......@@ -499,14 +499,18 @@ iscsi_allocmap_update(IscsiLun *iscsilun, int64_t sector_num,
if (allocated) {
bitmap_set(iscsilun->allocmap, cl_num_expanded, nb_cls_expanded);
} else {
bitmap_clear(iscsilun->allocmap, cl_num_shrunk, nb_cls_shrunk);
if (nb_cls_shrunk > 0) {
bitmap_clear(iscsilun->allocmap, cl_num_shrunk, nb_cls_shrunk);
}
}
if (iscsilun->allocmap_valid == NULL) {
return;
}
if (valid) {
bitmap_set(iscsilun->allocmap_valid, cl_num_shrunk, nb_cls_shrunk);
if (nb_cls_shrunk > 0) {
bitmap_set(iscsilun->allocmap_valid, cl_num_shrunk, nb_cls_shrunk);
}
} else {
bitmap_clear(iscsilun->allocmap_valid, cl_num_expanded,
nb_cls_expanded);
......
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