When running qcow2 over sheepdog, we might meet following problem
qemu-system-x86_64: shrinking is not supported
And cause IO errors to Guest. This is because we abuse bs->total_sectors, which
is manipulated by generic block layer and race with sheepdog code.
We should directly check if offset > vdi_size to dynamically enlarge the volume
instead of 'offset > bs->total_sectors', which will cause problem when following
case happens:
vdi_size > offset > bs->total_sectors
# then trigger sd_truncate() to shrink the volume wrongly.
Cc: qemu-devel@nongnu.org
Cc: Kevin Wolf <kw...@redhat.com>
Cc: Stefan Hajnoczi <stefa...@redhat.com>
Reported-by: Hadrien KOHL <hadrien.k...@gmail.com>
Signed-off-by: Liu Yuan <namei.u...@gmail.com>
---
block/sheepdog.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/block/sheepdog.c b/block/sheepdog.c
index d1c812d..ba451a9 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -2048,13 +2048,14 @@ static coroutine_fn int sd_co_writev(BlockDriverState
*bs, int64_t sector_num,
{
SheepdogAIOCB *acb;
int ret;
+ int64_t offset = (sector_num + nb_sectors) * BDRV_SECTOR_SIZE;
+ BDRVSheepdogState *s = bs->opaque;
- if (bs->growable && sector_num + nb_sectors > bs->total_sectors) {
- ret = sd_truncate(bs, (sector_num + nb_sectors) * BDRV_SECTOR_SIZE);
+ if (bs->growable && offset > s->inode.vdi_size) {
+ ret = sd_truncate(bs, offset);
if (ret < 0) {
return ret;
}
- bs->total_sectors = sector_num + nb_sectors;
}
acb = sd_aio_setup(bs, qiov, sector_num, nb_sectors);
--
1.7.9.5
