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Re: [PATCH v2 4/6] block: support compressed write for copy-on-read
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
Re: [PATCH v2 4/6] block: support compressed write for copy-on-read |
Date: |
Thu, 3 Oct 2019 14:37:27 +0000 |
02.10.2019 17:22, Andrey Shinkevich wrote:
> Support the data compression during block-stream job over a backup
> backing chain implemented in the following patch 'block-stream:
> add compress option'.
>
> Signed-off-by: Anton Nefedov <address@hidden>
> Signed-off-by: Denis V. Lunev <address@hidden>
> Signed-off-by: Andrey Shinkevich <address@hidden>
> ---
> block/io.c | 21 ++++++++++++++++-----
> block/trace-events | 2 +-
> 2 files changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/block/io.c b/block/io.c
> index f8c3596..a7cd24f 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -1264,12 +1264,13 @@ static int coroutine_fn
> bdrv_co_do_copy_on_readv(BdrvChild *child,
> * allocating cluster in the image file. Note that this value may
> exceed
> * BDRV_REQUEST_MAX_BYTES (even when the original read did not), which
> * is one reason we loop rather than doing it all at once.
> + * Also, this is crucial for compressed copy-on-read.
> */
> bdrv_round_to_clusters(bs, offset, bytes, &cluster_offset,
> &cluster_bytes);
> skip_bytes = offset - cluster_offset;
>
> trace_bdrv_co_do_copy_on_readv(bs, offset, bytes,
> - cluster_offset, cluster_bytes);
> + cluster_offset, cluster_bytes, flags);
>
> while (cluster_bytes) {
> int64_t pnum;
> @@ -1328,9 +1329,15 @@ static int coroutine_fn
> bdrv_co_do_copy_on_readv(BdrvChild *child,
> /* This does not change the data on the disk, it is not
> * necessary to flush even in cache=writethrough mode.
> */
> - ret = bdrv_driver_pwritev(bs, cluster_offset, pnum,
> - &local_qiov, 0,
> - BDRV_REQ_WRITE_UNCHANGED);
> + if (flags & BDRV_REQ_WRITE_COMPRESSED) {
> + ret = bdrv_driver_pwritev_compressed(bs, cluster_offset,
> + pnum, &local_qiov,
> + qiov_offset);
qiov_offset is wrong: you should use 0 together with local_qiov, as local_qiov
is buffer with
data to be written.
> + } else {
> + ret = bdrv_driver_pwritev(bs, cluster_offset, pnum,
> + &local_qiov, 0,
> + BDRV_REQ_WRITE_UNCHANGED);
> + }
> }
>
> if (ret < 0) {
> @@ -1396,7 +1403,11 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild
> *child,
> * to pass through to drivers. For now, there aren't any
> * passthrough flags. */
> assert(!(flags & ~(BDRV_REQ_NO_SERIALISING | BDRV_REQ_COPY_ON_READ |
> - BDRV_REQ_PREFETCH)));
> + BDRV_REQ_PREFETCH | BDRV_REQ_WRITE_COMPRESSED)));
> +
> + /* write compressed only makes sense with copy on read */
> + assert(!(flags & BDRV_REQ_WRITE_COMPRESSED) ||
> + (flags & BDRV_REQ_COPY_ON_READ));
>
> /* Handle Copy on Read and associated serialisation */
> if (flags & BDRV_REQ_COPY_ON_READ) {
> diff --git a/block/trace-events b/block/trace-events
> index 3aa27e6..f444548 100644
> --- a/block/trace-events
> +++ b/block/trace-events
> @@ -14,7 +14,7 @@ blk_root_detach(void *child, void *blk, void *bs) "child %p
> blk %p bs %p"
> bdrv_co_preadv(void *bs, int64_t offset, int64_t nbytes, unsigned int
> flags) "bs %p offset %"PRId64" nbytes %"PRId64" flags 0x%x"
> bdrv_co_pwritev(void *bs, int64_t offset, int64_t nbytes, unsigned int
> flags) "bs %p offset %"PRId64" nbytes %"PRId64" flags 0x%x"
> bdrv_co_pwrite_zeroes(void *bs, int64_t offset, int count, int flags) "bs
> %p offset %"PRId64" count %d flags 0x%x"
> -bdrv_co_do_copy_on_readv(void *bs, int64_t offset, unsigned int bytes,
> int64_t cluster_offset, int64_t cluster_bytes) "bs %p offset %"PRId64" bytes
> %u cluster_offset %"PRId64" cluster_bytes %"PRId64
> +bdrv_co_do_copy_on_readv(void *bs, int64_t offset, unsigned int bytes,
> int64_t cluster_offset, int64_t cluster_bytes, int flags) "bs %p offset
> %"PRId64" bytes %u cluster_offset %"PRId64" cluster_bytes %"PRId64" flags
> 0x%x"
> bdrv_co_copy_range_from(void *src, uint64_t src_offset, void *dst, uint64_t
> dst_offset, uint64_t bytes, int read_flags, int write_flags) "src %p offset
> %"PRIu64" dst %p offset %"PRIu64" bytes %"PRIu64" rw flags 0x%x 0x%x"
> bdrv_co_copy_range_to(void *src, uint64_t src_offset, void *dst, uint64_t
> dst_offset, uint64_t bytes, int read_flags, int write_flags) "src %p offset
> %"PRIu64" dst %p offset %"PRIu64" bytes %"PRIu64" rw flags 0x%x 0x%x"
>
>
--
Best regards,
Vladimir
- [PATCH v2 0/6] qcow2: advanced compression options, Andrey Shinkevich, 2019/10/02
- [PATCH v2 4/6] block: support compressed write for copy-on-read, Andrey Shinkevich, 2019/10/02
- Re: [PATCH v2 4/6] block: support compressed write for copy-on-read,
Vladimir Sementsov-Ogievskiy <=
- [PATCH v2 1/6] qcow2: Allow writing compressed data to multiple clusters, Andrey Shinkevich, 2019/10/02
- [PATCH v2 2/6] tests/qemu-iotests: add case of writing compressed data to multiple clusters, Andrey Shinkevich, 2019/10/02
- [PATCH v2 3/6] qemu-nbd: add compression flag support, Andrey Shinkevich, 2019/10/02
- [PATCH v2 5/6] block-stream: add compress option, Andrey Shinkevich, 2019/10/02