On 13.06.2016 17:32, Eric Blake wrote:
On 05/31/2016 03:15 AM, Denis V. Lunev wrote:
From: Pavel Butsykin <pbutsy...@virtuozzo.com>
This patch just adds the interface to the bdrv_co_pwritev_compressed,
which is currently not used but will be useful for safe implementation of the
bdrv_co_write_compressed callback in format drivers.
Signed-off-by: Pavel Butsykin <pbutsy...@virtuozzo.com>
Signed-off-by: Denis V. Lunev <d...@openvz.org>
CC: Jeff Cody <jc...@redhat.com>
CC: Markus Armbruster <arm...@redhat.com>
CC: Eric Blake <ebl...@redhat.com>
CC: John Snow <js...@redhat.com>
CC: Stefan Hajnoczi <stefa...@redhat.com>
CC: Kevin Wolf <kw...@redhat.com>
---
block/io.c | 78 +++++++++++++++++++++++++++++++++++++++++++----
include/block/block_int.h | 5 +++
qemu-img.c | 2 +-
3 files changed, 78 insertions(+), 7 deletions(-)
diff --git a/block/io.c b/block/io.c
index c5bb6ae..54cd9a4 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1779,8 +1779,8 @@ int bdrv_is_allocated_above(BlockDriverState *top,
return 0;
}
-int bdrv_pwrite_compressed(BlockDriverState *bs, int64_t offset,
- const void *buf, int count)
+int coroutine_fn bdrv_co_pwritev_compressed(BlockDriverState *bs,
+ int64_t offset, unsigned int bytes, QEMUIOVector *qiov)
Why the rename s/count/bytes/? Would it be better to get the name right
in 1/11?
It made like the bdrv_co_pwritev interface. For the
bdrv_pwrite_compressed() func also need rename s/count/bytes/ in 1/11.
{
BlockDriver *drv = bs->drv;
int ret;
@@ -1788,18 +1788,84 @@ int bdrv_pwrite_compressed(BlockDriverState *bs,
int64_t offset,
if (!drv) {
return -ENOMEDIUM;
}
- if (!drv->bdrv_write_compressed) {
+
+ if (!drv->bdrv_co_write_compressed) {
return -ENOTSUP;
This is a (temporary) regression - since none of the drivers have
.bdrv_co_write_compressed yet, you will always fail. Rather, the
transition period should support both interfaces at once...
}
- ret = bdrv_check_byte_request(bs, offset, count);
+
+ ret = bdrv_check_byte_request(bs, offset, bytes);
if (ret < 0) {
return ret;
}
assert(QLIST_EMPTY(&bs->dirty_bitmaps));
+ assert(qemu_in_coroutine());
+
+ return drv->bdrv_co_write_compressed(bs, offset >> BDRV_SECTOR_BITS,
+ bytes >> BDRV_SECTOR_BITS, qiov);
...and call into either the old or the new interface according to what
is present.
+int bdrv_pwrite_compressed(BlockDriverState *bs, int64_t offset,
+ const void *buf, int count)
+{
+ BdrvWriteCompressedCo data;
+ QEMUIOVector qiov;
+ BlockDriver *drv = bs->drv;
+ struct iovec iov = {
+ .iov_base = (void *)buf,
+ .iov_len = count,
+ };
+ qemu_iovec_init_external(&qiov, &iov, 1);
- return drv->bdrv_write_compressed(bs, offset >> BDRV_SECTOR_BITS, buf,
- count >> BDRV_SECTOR_BITS);
+ data = (BdrvWriteCompressedCo) {
+ .bs = bs,
+ .offset = offset,
+ .qiov = &qiov,
+ .ret = -EINPROGRESS,
+ };
+
+ if (!drv) {
+ return -ENOMEDIUM;
+ }
+
+ if (drv->bdrv_write_compressed) {
+ int ret = bdrv_check_byte_request(bs, offset, count);
+ if (ret < 0) {
+ return ret;
+ }
+ assert(QLIST_EMPTY(&bs->dirty_bitmaps));
+ return drv->bdrv_write_compressed(bs, offset >> BDRV_SECTOR_BITS, buf,
+ count >> BDRV_SECTOR_BITS);
+ }
Oh, you're catering to the old code up front, without a coroutine, and
only the new code gets coroutine treatment. Maybe it's okay after all.
Yes, it is made for a gradual transition from
drv->bdrv_write_compressed to drv->bdrv_co_write_compressed.
+
+ if (qemu_in_coroutine()) {
+ /* Fast-path if already in coroutine context */
+ bdrv_write_compressed_co_entry(&data);
+ } else {
+ AioContext *aio_context = bdrv_get_aio_context(bs);
+
+ Coroutine *co = qemu_coroutine_create(bdrv_write_compressed_co_entry);
+ qemu_coroutine_enter(co, &data);
+ while (data.ret == -EINPROGRESS) {
+ aio_poll(aio_context, true);
+ }
+ }
+ return data.ret;
}
int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 30a9717..ccba9c9 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -207,6 +207,9 @@ struct BlockDriver {
int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors);
+ int coroutine_fn (*bdrv_co_write_compressed)(BlockDriverState *bs,
Might be better to name this bdrv_co_pwrite_compressed if we want to
make it byte-based...
+ int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
...it seems odd that you have to add a new sector-based interface given
that you are trying to convert to byte-based.
When I sent this patch, Kevin had not yet converted the sector-based
interfaces to byte-based for format drivers :)
+
int (*bdrv_snapshot_create)(BlockDriverState *bs,
QEMUSnapshotInfo *sn_info);
int (*bdrv_snapshot_goto)(BlockDriverState *bs,
@@ -535,6 +538,8 @@ int coroutine_fn bdrv_co_preadv(BlockDriverState *bs,
int coroutine_fn bdrv_co_pwritev(BlockDriverState *bs,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);
+int coroutine_fn bdrv_co_pwritev_compressed(BlockDriverState *bs,
+ int64_t offset, unsigned int bytes, QEMUIOVector *qiov);
int get_tmp_filename(char *filename, int size);
BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
diff --git a/qemu-img.c b/qemu-img.c
index eb744d4..ab54027 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2024,7 +2024,7 @@ static int img_convert(int argc, char **argv)
const char *preallocation =
qemu_opt_get(opts, BLOCK_OPT_PREALLOC);
- if (!drv->bdrv_write_compressed) {
+ if (!drv->bdrv_write_compressed && !drv->bdrv_co_write_compressed) {
error_report("Compression not supported for this file format");
ret = -1;
goto out;