From 244483e64ee726cc89a1e05bed2be0ed37071403 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Thu, 2 Jun 2016 11:41:52 +0200 Subject: [PATCH] block: Byte-based bdrv_co_do_copy_on_readv() In a first step to convert the common I/O path to work on bytes rather than sectors, this converts the copy-on-read logic that is used by bdrv_aligned_preadv(). Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake Reviewed-by: Stefan Hajnoczi --- block/io.c | 63 ++++++++++++++++++++++++++----------------- block/mirror.c | 10 ++++--- include/block/block.h | 10 ++++--- trace-events | 2 +- 4 files changed, 52 insertions(+), 33 deletions(-) diff --git a/block/io.c b/block/io.c index 5b2017fedc..b6a2c800a1 100644 --- a/block/io.c +++ b/block/io.c @@ -404,12 +404,12 @@ static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) } /** - * Round a region to cluster boundaries + * Round a region to cluster boundaries (sector-based) */ -void bdrv_round_to_clusters(BlockDriverState *bs, - int64_t sector_num, int nb_sectors, - int64_t *cluster_sector_num, - int *cluster_nb_sectors) +void bdrv_round_sectors_to_clusters(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, + int64_t *cluster_sector_num, + int *cluster_nb_sectors) { BlockDriverInfo bdi; @@ -424,6 +424,26 @@ void bdrv_round_to_clusters(BlockDriverState *bs, } } +/** + * Round a region to cluster boundaries + */ +void bdrv_round_to_clusters(BlockDriverState *bs, + int64_t offset, unsigned int bytes, + int64_t *cluster_offset, + unsigned int *cluster_bytes) +{ + BlockDriverInfo bdi; + + if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) { + *cluster_offset = offset; + *cluster_bytes = bytes; + } else { + int64_t c = bdi.cluster_size; + *cluster_offset = QEMU_ALIGN_DOWN(offset, c); + *cluster_bytes = QEMU_ALIGN_UP(offset - *cluster_offset + bytes, c); + } +} + static int bdrv_get_cluster_size(BlockDriverState *bs) { BlockDriverInfo bdi; @@ -865,7 +885,7 @@ emulate_flags: } static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, - int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) + int64_t offset, unsigned int bytes, QEMUIOVector *qiov) { /* Perform I/O through a temporary buffer so that users who scribble over * their read buffer while the operation is in progress do not end up @@ -877,21 +897,20 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, BlockDriver *drv = bs->drv; struct iovec iov; QEMUIOVector bounce_qiov; - int64_t cluster_sector_num; - int cluster_nb_sectors; + int64_t cluster_offset; + unsigned int cluster_bytes; size_t skip_bytes; int ret; /* Cover entire cluster so no additional backing file I/O is required when * allocating cluster in the image file. */ - bdrv_round_to_clusters(bs, sector_num, nb_sectors, - &cluster_sector_num, &cluster_nb_sectors); + bdrv_round_to_clusters(bs, offset, bytes, &cluster_offset, &cluster_bytes); - trace_bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, - cluster_sector_num, cluster_nb_sectors); + trace_bdrv_co_do_copy_on_readv(bs, offset, bytes, + cluster_offset, cluster_bytes); - iov.iov_len = cluster_nb_sectors * BDRV_SECTOR_SIZE; + iov.iov_len = cluster_bytes; iov.iov_base = bounce_buffer = qemu_try_blockalign(bs, iov.iov_len); if (bounce_buffer == NULL) { ret = -ENOMEM; @@ -900,8 +919,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, qemu_iovec_init_external(&bounce_qiov, &iov, 1); - ret = bdrv_driver_preadv(bs, cluster_sector_num * BDRV_SECTOR_SIZE, - cluster_nb_sectors * BDRV_SECTOR_SIZE, + ret = bdrv_driver_preadv(bs, cluster_offset, cluster_bytes, &bounce_qiov, 0); if (ret < 0) { goto err; @@ -909,16 +927,12 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, if (drv->bdrv_co_pwrite_zeroes && buffer_is_zero(bounce_buffer, iov.iov_len)) { - ret = bdrv_co_do_pwrite_zeroes(bs, - cluster_sector_num * BDRV_SECTOR_SIZE, - cluster_nb_sectors * BDRV_SECTOR_SIZE, - 0); + ret = bdrv_co_do_pwrite_zeroes(bs, cluster_offset, cluster_bytes, 0); } else { /* 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_sector_num * BDRV_SECTOR_SIZE, - cluster_nb_sectors * BDRV_SECTOR_SIZE, + ret = bdrv_driver_pwritev(bs, cluster_offset, cluster_bytes, &bounce_qiov, 0); } @@ -930,9 +944,8 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, goto err; } - skip_bytes = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE; - qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes, - nb_sectors * BDRV_SECTOR_SIZE); + skip_bytes = offset - cluster_offset; + qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes, bytes); err: qemu_vfree(bounce_buffer); @@ -982,7 +995,7 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, } if (!ret || pnum != nb_sectors) { - ret = bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, qiov); + ret = bdrv_co_do_copy_on_readv(bs, offset, bytes, qiov); goto out; } } diff --git a/block/mirror.c b/block/mirror.c index 1f01f2488c..41848b2c8e 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -185,8 +185,9 @@ static int mirror_cow_align(MirrorBlockJob *s, need_cow |= !test_bit((*sector_num + *nb_sectors - 1) / chunk_sectors, s->cow_bitmap); if (need_cow) { - bdrv_round_to_clusters(blk_bs(s->target), *sector_num, *nb_sectors, - &align_sector_num, &align_nb_sectors); + bdrv_round_sectors_to_clusters(blk_bs(s->target), *sector_num, + *nb_sectors, &align_sector_num, + &align_nb_sectors); } if (align_nb_sectors > max_sectors) { @@ -384,8 +385,9 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) { int64_t target_sector_num; int target_nb_sectors; - bdrv_round_to_clusters(blk_bs(s->target), sector_num, io_sectors, - &target_sector_num, &target_nb_sectors); + bdrv_round_sectors_to_clusters(blk_bs(s->target), sector_num, + io_sectors, &target_sector_num, + &target_nb_sectors); if (target_sector_num == sector_num && target_nb_sectors == io_sectors) { mirror_method = ret & BDRV_BLOCK_ZERO ? diff --git a/include/block/block.h b/include/block/block.h index 8cabcddf6c..9c3a62cc0a 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -404,10 +404,14 @@ int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors); int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi); ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs); +void bdrv_round_sectors_to_clusters(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, + int64_t *cluster_sector_num, + int *cluster_nb_sectors); void bdrv_round_to_clusters(BlockDriverState *bs, - int64_t sector_num, int nb_sectors, - int64_t *cluster_sector_num, - int *cluster_nb_sectors); + int64_t offset, unsigned int bytes, + int64_t *cluster_offset, + unsigned int *cluster_bytes); const char *bdrv_get_encrypted_filename(BlockDriverState *bs); void bdrv_get_backing_filename(BlockDriverState *bs, diff --git a/trace-events b/trace-events index 720c644873..104b64fae1 100644 --- a/trace-events +++ b/trace-events @@ -73,7 +73,7 @@ bdrv_aio_writev(void *bs, int64_t sector_num, int nb_sectors, void *opaque) "bs bdrv_co_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d" bdrv_co_writev(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d" bdrv_co_pwrite_zeroes(void *bs, int64_t offset, int count, int flags) "bs %p offset %"PRId64" count %d flags %#x" -bdrv_co_do_copy_on_readv(void *bs, int64_t sector_num, int nb_sectors, int64_t cluster_sector_num, int cluster_nb_sectors) "bs %p sector_num %"PRId64" nb_sectors %d cluster_sector_num %"PRId64" cluster_nb_sectors %d" +bdrv_co_do_copy_on_readv(void *bs, int64_t offset, unsigned int bytes, int64_t cluster_offset, unsigned int cluster_bytes) "bs %p offset %"PRId64" bytes %u cluster_offset %"PRId64" cluster_bytes %u" # block/stream.c stream_one_iteration(void *s, int64_t sector_num, int nb_sectors, int is_allocated) "s %p sector_num %"PRId64" nb_sectors %d is_allocated %d"