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block: define .*_part io handlers in BlockDriver
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Add handlers supporting qiov_offset parameter:
    bdrv_co_preadv_part
    bdrv_co_pwritev_part
    bdrv_co_pwritev_compressed_part
This is used to reduce need of defining local_qiovs and hd_qiovs in all
corners of block layer code. The following patches will increase usage
of this new API part by part.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-5-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-5-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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@stefanhaRH
Vladimir Sementsov-Ogievskiy authored and stefanhaRH committed Aug 27, 2019
1 parent 7a3f542 commit ac850bf
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Showing 4 changed files with 95 additions and 22 deletions.
2 changes: 1 addition & 1 deletion block/backup.c
View file
Expand Up @@ -674,7 +674,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
return NULL;
}

if (compress && target->drv->bdrv_co_pwritev_compressed == NULL) {
if (compress && !block_driver_can_compress(target->drv)) {
error_setg(errp, "Compression is not supported for this drive %s",
bdrv_get_device_name(target));
return NULL;
Expand Down
96 changes: 77 additions & 19 deletions block/io.c
View file
Expand Up @@ -146,7 +146,8 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)

/* Default alignment based on whether driver has byte interface */
bs->bl.request_alignment = (drv->bdrv_co_preadv ||
drv->bdrv_aio_preadv) ? 1 : 512;
drv->bdrv_aio_preadv ||
drv->bdrv_co_preadv_part) ? 1 : 512;

/* Take some limits from the children as a default */
if (bs->file) {
Expand Down Expand Up @@ -1044,11 +1045,14 @@ static void bdrv_co_io_em_complete(void *opaque, int ret)

static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
QEMUIOVector *qiov,
size_t qiov_offset, int flags)
{
BlockDriver *drv = bs->drv;
int64_t sector_num;
unsigned int nb_sectors;
QEMUIOVector local_qiov;
int ret;

assert(!(flags & ~BDRV_REQ_MASK));
assert(!(flags & BDRV_REQ_NO_FALLBACK));
Expand All @@ -1057,8 +1061,19 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
return -ENOMEDIUM;
}

if (drv->bdrv_co_preadv_part) {
return drv->bdrv_co_preadv_part(bs, offset, bytes, qiov, qiov_offset,
flags);
}

if (qiov_offset > 0 || bytes != qiov->size) {
qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
qiov = &local_qiov;
}

if (drv->bdrv_co_preadv) {
return drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags);
ret = drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags);
goto out;
}

if (drv->bdrv_aio_preadv) {
Expand All @@ -1070,10 +1085,12 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
acb = drv->bdrv_aio_preadv(bs, offset, bytes, qiov, flags,
bdrv_co_io_em_complete, &co);
if (acb == NULL) {
return -EIO;
ret = -EIO;
goto out;
} else {
qemu_coroutine_yield();
return co.ret;
ret = co.ret;
goto out;
}
}

Expand All @@ -1085,16 +1102,25 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
assert(bytes <= BDRV_REQUEST_MAX_BYTES);
assert(drv->bdrv_co_readv);

return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);

out:
if (qiov == &local_qiov) {
qemu_iovec_destroy(&local_qiov);
}

return ret;
}

static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
QEMUIOVector *qiov,
size_t qiov_offset, int flags)
{
BlockDriver *drv = bs->drv;
int64_t sector_num;
unsigned int nb_sectors;
QEMUIOVector local_qiov;
int ret;

assert(!(flags & ~BDRV_REQ_MASK));
Expand All @@ -1104,6 +1130,18 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
return -ENOMEDIUM;
}

if (drv->bdrv_co_pwritev_part) {
ret = drv->bdrv_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset,
flags & bs->supported_write_flags);
flags &= ~bs->supported_write_flags;
goto emulate_flags;
}

if (qiov_offset > 0 || bytes != qiov->size) {
qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
qiov = &local_qiov;
}

if (drv->bdrv_co_pwritev) {
ret = drv->bdrv_co_pwritev(bs, offset, bytes, qiov,
flags & bs->supported_write_flags);
Expand Down Expand Up @@ -1147,24 +1185,44 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
ret = bdrv_co_flush(bs);
}

if (qiov == &local_qiov) {
qemu_iovec_destroy(&local_qiov);
}

return ret;
}

static int coroutine_fn
bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov)
uint64_t bytes, QEMUIOVector *qiov,
size_t qiov_offset)
{
BlockDriver *drv = bs->drv;
QEMUIOVector local_qiov;
int ret;

if (!drv) {
return -ENOMEDIUM;
}

if (!drv->bdrv_co_pwritev_compressed) {
if (!block_driver_can_compress(drv)) {
return -ENOTSUP;
}

return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov);
if (drv->bdrv_co_pwritev_compressed_part) {
return drv->bdrv_co_pwritev_compressed_part(bs, offset, bytes,
qiov, qiov_offset);
}

if (qiov_offset == 0) {
return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov);
}

qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
ret = drv->bdrv_co_pwritev_compressed(bs, offset, bytes, &local_qiov);
qemu_iovec_destroy(&local_qiov);

return ret;
}

static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
Expand Down Expand Up @@ -1249,7 +1307,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);

ret = bdrv_driver_preadv(bs, cluster_offset, pnum,
&local_qiov, 0);
&local_qiov, 0, 0);
if (ret < 0) {
goto err;
}
Expand All @@ -1267,7 +1325,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
* necessary to flush even in cache=writethrough mode.
*/
ret = bdrv_driver_pwritev(bs, cluster_offset, pnum,
&local_qiov,
&local_qiov, 0,
BDRV_REQ_WRITE_UNCHANGED);
}

Expand All @@ -1289,7 +1347,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
qemu_iovec_init(&local_qiov, qiov->niov);
qemu_iovec_concat(&local_qiov, qiov, progress, pnum - skip_bytes);
ret = bdrv_driver_preadv(bs, offset + progress, local_qiov.size,
&local_qiov, 0);
&local_qiov, 0, 0);
qemu_iovec_destroy(&local_qiov);
if (ret < 0) {
goto err;
Expand Down Expand Up @@ -1380,7 +1438,7 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,

max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
if (bytes <= max_bytes && bytes <= max_transfer) {
ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0);
ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0, 0);
goto out;
}

Expand All @@ -1396,7 +1454,7 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);

ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
num, &local_qiov, 0);
num, &local_qiov, 0, 0);
max_bytes -= num;
qemu_iovec_destroy(&local_qiov);
} else {
Expand Down Expand Up @@ -1701,7 +1759,7 @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
}
qemu_iovec_init_buf(&qiov, buf, num);

ret = bdrv_driver_pwritev(bs, offset, num, &qiov, write_flags);
ret = bdrv_driver_pwritev(bs, offset, num, &qiov, 0, write_flags);

/* Keep bounce buffer around if it is big enough for all
* all future requests.
Expand Down Expand Up @@ -1857,10 +1915,10 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO);
ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags);
} else if (flags & BDRV_REQ_WRITE_COMPRESSED) {
ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, qiov);
ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, qiov, 0);
} else if (bytes <= max_transfer) {
bdrv_debug_event(bs, BLKDBG_PWRITEV);
ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, flags);
ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, 0, flags);
} else {
bdrv_debug_event(bs, BLKDBG_PWRITEV);
while (bytes_remaining) {
Expand All @@ -1879,7 +1937,7 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);

ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining,
num, &local_qiov, local_flags);
num, &local_qiov, 0, local_flags);
qemu_iovec_destroy(&local_qiov);
if (ret < 0) {
break;
Expand Down
15 changes: 15 additions & 0 deletions include/block/block_int.h
View file
Expand Up @@ -210,6 +210,9 @@ struct BlockDriver {
*/
int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);
int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset, int flags);
int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags);
/**
Expand All @@ -229,6 +232,9 @@ struct BlockDriver {
*/
int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);
int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset, int flags);

/*
* Efficiently zero a region of the disk image. Typically an image format
Expand Down Expand Up @@ -339,6 +345,9 @@ struct BlockDriver {

int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov);
int coroutine_fn (*bdrv_co_pwritev_compressed_part)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov,
size_t qiov_offset);

int (*bdrv_snapshot_create)(BlockDriverState *bs,
QEMUSnapshotInfo *sn_info);
Expand Down Expand Up @@ -570,6 +579,12 @@ struct BlockDriver {
const char *const *strong_runtime_opts;
};

static inline bool block_driver_can_compress(BlockDriver *drv)
{
return drv->bdrv_co_pwritev_compressed ||
drv->bdrv_co_pwritev_compressed_part;
}

typedef struct BlockLimits {
/* Alignment requirement, in bytes, for offset/length of I/O
* requests. Must be a power of 2 less than INT_MAX; defaults to
Expand Down
4 changes: 2 additions & 2 deletions qemu-img.c
View file
Expand Up @@ -2388,7 +2388,7 @@ static int img_convert(int argc, char **argv)
const char *preallocation =
qemu_opt_get(opts, BLOCK_OPT_PREALLOC);

if (drv && !drv->bdrv_co_pwritev_compressed) {
if (drv && !block_driver_can_compress(drv)) {
error_report("Compression not supported for this file format");
ret = -1;
goto out;
Expand Down Expand Up @@ -2459,7 +2459,7 @@ static int img_convert(int argc, char **argv)
}
out_bs = blk_bs(s.target);

if (s.compressed && !out_bs->drv->bdrv_co_pwritev_compressed) {
if (s.compressed && !block_driver_can_compress(out_bs->drv)) {
error_report("Compression not supported for this file format");
ret = -1;
goto out;
Expand Down

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