| Message ID | 1463503863-19009-3-git-send-email-kwolf@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 05/17/2016 10:51 AM, Kevin Wolf wrote: > In order to correctly check whether a given cluster is read as zero, we > don't only need to check whether bdrv_get_block_status_above() sets > BDRV_BLOCK_ZERO, but also if all sectors for the whole cluster have the > same status. > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > block/qcow2.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > Reviewed-by: Eric Blake <eblake@redhat.com>
On 05/17/2016 07:51 PM, Kevin Wolf wrote: > In order to correctly check whether a given cluster is read as zero, we > don't only need to check whether bdrv_get_block_status_above() sets > BDRV_BLOCK_ZERO, but also if all sectors for the whole cluster have the > same status. > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > block/qcow2.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/block/qcow2.c b/block/qcow2.c > index a6012dc..c197ff3 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -2412,7 +2412,7 @@ static bool is_zero_cluster(BlockDriverState *bs, int64_t start) > BlockDriverState *file; > int64_t res = bdrv_get_block_status_above(bs, NULL, start, > s->cluster_sectors, &nr, &file); > - return res >= 0 && (res & BDRV_BLOCK_ZERO); > + return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == s->cluster_sectors; > } > > static bool is_zero_cluster_top_locked(BlockDriverState *bs, int64_t start) > @@ -2423,6 +2423,7 @@ static bool is_zero_cluster_top_locked(BlockDriverState *bs, int64_t start) > int ret; > > ret = qcow2_get_cluster_offset(bs, start << BDRV_SECTOR_BITS, &nr, &off); > + assert(nr == s->cluster_sectors); > return ret == QCOW2_CLUSTER_UNALLOCATED || ret == QCOW2_CLUSTER_ZERO; > } > Reviewed-by: Denis V. Lunev <den@openvz.org> I have had this kludge in the revision one and I have lost them in revision 3 :(
diff --git a/block/qcow2.c b/block/qcow2.c index a6012dc..c197ff3 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2412,7 +2412,7 @@ static bool is_zero_cluster(BlockDriverState *bs, int64_t start) BlockDriverState *file; int64_t res = bdrv_get_block_status_above(bs, NULL, start, s->cluster_sectors, &nr, &file); - return res >= 0 && (res & BDRV_BLOCK_ZERO); + return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == s->cluster_sectors; } static bool is_zero_cluster_top_locked(BlockDriverState *bs, int64_t start) @@ -2423,6 +2423,7 @@ static bool is_zero_cluster_top_locked(BlockDriverState *bs, int64_t start) int ret; ret = qcow2_get_cluster_offset(bs, start << BDRV_SECTOR_BITS, &nr, &off); + assert(nr == s->cluster_sectors); return ret == QCOW2_CLUSTER_UNALLOCATED || ret == QCOW2_CLUSTER_ZERO; }
In order to correctly check whether a given cluster is read as zero, we don't only need to check whether bdrv_get_block_status_above() sets BDRV_BLOCK_ZERO, but also if all sectors for the whole cluster have the same status. Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/qcow2.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)