block/backup-top.c | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-)
backup-top "supports" write-unchanged, by skipping CBW operation in
backup_top_co_pwritev. But it forgets to do the same in
backup_top_co_pwrite_zeroes, as well as declare support for
BDRV_REQ_WRITE_UNCHANGED.
Fix this, and, while being here, declare also support for flags
supported by source child.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
v2: restrict flags propagation like it is done in other filters [Eric]
move state variable initialization to the top
block/backup-top.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/block/backup-top.c b/block/backup-top.c
index 9aed2eb4c0..a4cec60859 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -48,11 +48,17 @@ static coroutine_fn int backup_top_co_preadv(
}
static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset,
- uint64_t bytes)
+ uint64_t bytes, BdrvRequestFlags flags)
{
BDRVBackupTopState *s = bs->opaque;
- uint64_t end = QEMU_ALIGN_UP(offset + bytes, s->bcs->cluster_size);
- uint64_t off = QEMU_ALIGN_DOWN(offset, s->bcs->cluster_size);
+ uint64_t off, end;
+
+ if (flags & BDRV_REQ_WRITE_UNCHANGED) {
+ return 0;
+ }
+
+ off = QEMU_ALIGN_DOWN(offset, s->bcs->cluster_size);
+ end = QEMU_ALIGN_UP(offset + bytes, s->bcs->cluster_size);
return block_copy(s->bcs, off, end - off, NULL);
}
@@ -60,7 +66,7 @@ static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset,
static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs,
int64_t offset, int bytes)
{
- int ret = backup_top_cbw(bs, offset, bytes);
+ int ret = backup_top_cbw(bs, offset, bytes, 0);
if (ret < 0) {
return ret;
}
@@ -71,7 +77,7 @@ static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs,
static int coroutine_fn backup_top_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int bytes, BdrvRequestFlags flags)
{
- int ret = backup_top_cbw(bs, offset, bytes);
+ int ret = backup_top_cbw(bs, offset, bytes, flags);
if (ret < 0) {
return ret;
}
@@ -84,11 +90,9 @@ static coroutine_fn int backup_top_co_pwritev(BlockDriverState *bs,
uint64_t bytes,
QEMUIOVector *qiov, int flags)
{
- if (!(flags & BDRV_REQ_WRITE_UNCHANGED)) {
- int ret = backup_top_cbw(bs, offset, bytes);
- if (ret < 0) {
- return ret;
- }
+ int ret = backup_top_cbw(bs, offset, bytes, flags);
+ if (ret < 0) {
+ return ret;
}
return bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags);
@@ -186,17 +190,21 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
Error **errp)
{
Error *local_err = NULL;
- BDRVBackupTopState *state;
BlockDriverState *top = bdrv_new_open_driver(&bdrv_backup_top_filter,
filter_node_name,
BDRV_O_RDWR, errp);
+ BDRVBackupTopState *state = top->opaque;
if (!top) {
return NULL;
}
top->total_sectors = source->total_sectors;
- state = top->opaque;
+ top->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
+ (BDRV_REQ_FUA & source->supported_write_flags);
+ top->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
+ ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
+ source->supported_zero_flags);
bdrv_ref(target);
state->target = bdrv_attach_child(top, target, "target", &child_file, errp);
--
2.21.0
On 2/3/20 7:42 AM, Vladimir Sementsov-Ogievskiy wrote: > backup-top "supports" write-unchanged, by skipping CBW operation in > backup_top_co_pwritev. But it forgets to do the same in > backup_top_co_pwrite_zeroes, as well as declare support for > BDRV_REQ_WRITE_UNCHANGED. > > Fix this, and, while being here, declare also support for flags > supported by source child. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- Reviewed-by: Eric Blake <eblake@redhat.com> -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org
03.02.2020 18:42, Eric Blake wrote: > On 2/3/20 7:42 AM, Vladimir Sementsov-Ogievskiy wrote: >> backup-top "supports" write-unchanged, by skipping CBW operation in >> backup_top_co_pwritev. But it forgets to do the same in >> backup_top_co_pwrite_zeroes, as well as declare support for >> BDRV_REQ_WRITE_UNCHANGED. >> >> Fix this, and, while being here, declare also support for flags >> supported by source child. >> >> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> >> --- > > Reviewed-by: Eric Blake <eblake@redhat.com> > Thanks! -- Best regards, Vladimir
On 03.02.20 14:42, Vladimir Sementsov-Ogievskiy wrote:
> backup-top "supports" write-unchanged, by skipping CBW operation in
> backup_top_co_pwritev. But it forgets to do the same in
> backup_top_co_pwrite_zeroes, as well as declare support for
> BDRV_REQ_WRITE_UNCHANGED.
>
> Fix this, and, while being here, declare also support for flags
> supported by source child.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>
> v2: restrict flags propagation like it is done in other filters [Eric]
> move state variable initialization to the top
>
> block/backup-top.c | 32 ++++++++++++++++++++------------
> 1 file changed, 20 insertions(+), 12 deletions(-)
>
> diff --git a/block/backup-top.c b/block/backup-top.c
> index 9aed2eb4c0..a4cec60859 100644
> --- a/block/backup-top.c
> +++ b/block/backup-top.c
[...]
> @@ -186,17 +190,21 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
> Error **errp)
> {
> Error *local_err = NULL;
> - BDRVBackupTopState *state;
> BlockDriverState *top = bdrv_new_open_driver(&bdrv_backup_top_filter,
> filter_node_name,
> BDRV_O_RDWR, errp);
> + BDRVBackupTopState *state = top->opaque;
>
> if (!top) {
> return NULL;
> }
If top can be NULL, then we shouldn’t dereference it before (with
state = top->opaque).
(Pulling up the initialization of @state is also unrelated to this
patch, I don’t exactly know why you’re doing it here.)
Max
06.02.2020 19:31, Max Reitz wrote:
> On 03.02.20 14:42, Vladimir Sementsov-Ogievskiy wrote:
>> backup-top "supports" write-unchanged, by skipping CBW operation in
>> backup_top_co_pwritev. But it forgets to do the same in
>> backup_top_co_pwrite_zeroes, as well as declare support for
>> BDRV_REQ_WRITE_UNCHANGED.
>>
>> Fix this, and, while being here, declare also support for flags
>> supported by source child.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>
>> v2: restrict flags propagation like it is done in other filters [Eric]
>> move state variable initialization to the top
>>
>> block/backup-top.c | 32 ++++++++++++++++++++------------
>> 1 file changed, 20 insertions(+), 12 deletions(-)
>>
>> diff --git a/block/backup-top.c b/block/backup-top.c
>> index 9aed2eb4c0..a4cec60859 100644
>> --- a/block/backup-top.c
>> +++ b/block/backup-top.c
>
>
> [...]
>
>> @@ -186,17 +190,21 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
>> Error **errp)
>> {
>> Error *local_err = NULL;
>> - BDRVBackupTopState *state;
>> BlockDriverState *top = bdrv_new_open_driver(&bdrv_backup_top_filter,
>> filter_node_name,
>> BDRV_O_RDWR, errp);
>> + BDRVBackupTopState *state = top->opaque;
>>
>> if (!top) {
>> return NULL;
>> }
>
> If top can be NULL, then we shouldn’t dereference it before (with
> state = top->opaque).
Oh yes.
>
> (Pulling up the initialization of @state is also unrelated to this
> patch, I don’t exactly know why you’re doing it here.)
>
I just though, that it is small good style enhancement, but it isn't :)
Let's keep state variable handling as it was.
--
Best regards,
Vladimir
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