From 9c4269d54b8bcc1939641009a2ea9b24d887fd58 Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Fri, 10 Jul 2020 18:12:43 +0200 Subject: [PATCH] qcow2: Make Qcow2AioTask store the full host offset The file_cluster_offset field of Qcow2AioTask stores a cluster-aligned host offset. In practice this is not very useful because all users(*) of this structure need the final host offset into the cluster, which they calculate using host_offset = file_cluster_offset + offset_into_cluster(s, offset) There is no reason why Qcow2AioTask cannot store host_offset directly and that is what this patch does. (*) compressed clusters are the exception: in this case what file_cluster_offset was storing was the full compressed cluster descriptor (offset + size). This does not change with this patch but it is documented now. Signed-off-by: Alberto Garcia Reviewed-by: Eric Blake Reviewed-by: Max Reitz Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <07c4b15c644dcf06c9459f98846ac1c4ea96e26f.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz --- block/qcow2.c | 69 ++++++++++++++++++++++++++---------------------------- block/trace-events | 2 +- 2 files changed, 34 insertions(+), 37 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 6ad6bdc166..5ab1f45fe2 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -74,7 +74,7 @@ typedef struct { static int coroutine_fn qcow2_co_preadv_compressed(BlockDriverState *bs, - uint64_t file_cluster_offset, + uint64_t cluster_descriptor, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, @@ -2113,7 +2113,7 @@ out: static coroutine_fn int qcow2_co_preadv_encrypted(BlockDriverState *bs, - uint64_t file_cluster_offset, + uint64_t host_offset, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, @@ -2140,16 +2140,12 @@ qcow2_co_preadv_encrypted(BlockDriverState *bs, } BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); - ret = bdrv_co_pread(s->data_file, - file_cluster_offset + offset_into_cluster(s, offset), - bytes, buf, 0); + ret = bdrv_co_pread(s->data_file, host_offset, bytes, buf, 0); if (ret < 0) { goto fail; } - if (qcow2_co_decrypt(bs, - file_cluster_offset + offset_into_cluster(s, offset), - offset, buf, bytes) < 0) + if (qcow2_co_decrypt(bs, host_offset, offset, buf, bytes) < 0) { ret = -EIO; goto fail; @@ -2167,7 +2163,7 @@ typedef struct Qcow2AioTask { BlockDriverState *bs; QCow2ClusterType cluster_type; /* only for read */ - uint64_t file_cluster_offset; + uint64_t host_offset; /* or full descriptor in compressed clusters */ uint64_t offset; uint64_t bytes; QEMUIOVector *qiov; @@ -2180,7 +2176,7 @@ static coroutine_fn int qcow2_add_task(BlockDriverState *bs, AioTaskPool *pool, AioTaskFunc func, QCow2ClusterType cluster_type, - uint64_t file_cluster_offset, + uint64_t host_offset, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, @@ -2195,7 +2191,7 @@ static coroutine_fn int qcow2_add_task(BlockDriverState *bs, .bs = bs, .cluster_type = cluster_type, .qiov = qiov, - .file_cluster_offset = file_cluster_offset, + .host_offset = host_offset, .offset = offset, .bytes = bytes, .qiov_offset = qiov_offset, @@ -2204,7 +2200,7 @@ static coroutine_fn int qcow2_add_task(BlockDriverState *bs, trace_qcow2_add_task(qemu_coroutine_self(), bs, pool, func == qcow2_co_preadv_task_entry ? "read" : "write", - cluster_type, file_cluster_offset, offset, bytes, + cluster_type, host_offset, offset, bytes, qiov, qiov_offset); if (!pool) { @@ -2218,13 +2214,12 @@ static coroutine_fn int qcow2_add_task(BlockDriverState *bs, static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs, QCow2ClusterType cluster_type, - uint64_t file_cluster_offset, + uint64_t host_offset, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, size_t qiov_offset) { BDRVQcow2State *s = bs->opaque; - int offset_in_cluster = offset_into_cluster(s, offset); switch (cluster_type) { case QCOW2_CLUSTER_ZERO_PLAIN: @@ -2240,19 +2235,17 @@ static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs, qiov, qiov_offset, 0); case QCOW2_CLUSTER_COMPRESSED: - return qcow2_co_preadv_compressed(bs, file_cluster_offset, + return qcow2_co_preadv_compressed(bs, host_offset, offset, bytes, qiov, qiov_offset); case QCOW2_CLUSTER_NORMAL: - assert(offset_into_cluster(s, file_cluster_offset) == 0); if (bs->encrypted) { - return qcow2_co_preadv_encrypted(bs, file_cluster_offset, + return qcow2_co_preadv_encrypted(bs, host_offset, offset, bytes, qiov, qiov_offset); } BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); - return bdrv_co_preadv_part(s->data_file, - file_cluster_offset + offset_in_cluster, + return bdrv_co_preadv_part(s->data_file, host_offset, bytes, qiov, qiov_offset, 0); default: @@ -2268,7 +2261,7 @@ static coroutine_fn int qcow2_co_preadv_task_entry(AioTask *task) assert(!t->l2meta); - return qcow2_co_preadv_task(t->bs, t->cluster_type, t->file_cluster_offset, + return qcow2_co_preadv_task(t->bs, t->cluster_type, t->host_offset, t->offset, t->bytes, t->qiov, t->qiov_offset); } @@ -2304,11 +2297,20 @@ static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs, { qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes); } else { + /* + * For compressed clusters the variable cluster_offset + * does not actually store the offset but the full + * descriptor. We need to leave it unchanged because + * that's what qcow2_co_preadv_compressed() expects. + */ + uint64_t host_offset = (ret == QCOW2_CLUSTER_COMPRESSED) ? + cluster_offset : + cluster_offset + offset_into_cluster(s, offset); if (!aio && cur_bytes != bytes) { aio = aio_task_pool_new(QCOW2_MAX_WORKERS); } ret = qcow2_add_task(bs, aio, qcow2_co_preadv_task_entry, ret, - cluster_offset, offset, cur_bytes, + host_offset, offset, cur_bytes, qiov, qiov_offset, NULL); if (ret < 0) { goto out; @@ -2459,7 +2461,7 @@ static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta) * not use it somehow after qcow2_co_pwritev_task() call */ static coroutine_fn int qcow2_co_pwritev_task(BlockDriverState *bs, - uint64_t file_cluster_offset, + uint64_t host_offset, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, uint64_t qiov_offset, @@ -2468,7 +2470,6 @@ static coroutine_fn int qcow2_co_pwritev_task(BlockDriverState *bs, int ret; BDRVQcow2State *s = bs->opaque; void *crypt_buf = NULL; - int offset_in_cluster = offset_into_cluster(s, offset); QEMUIOVector encrypted_qiov; if (bs->encrypted) { @@ -2481,9 +2482,7 @@ static coroutine_fn int qcow2_co_pwritev_task(BlockDriverState *bs, } qemu_iovec_to_buf(qiov, qiov_offset, crypt_buf, bytes); - if (qcow2_co_encrypt(bs, file_cluster_offset + offset_in_cluster, - offset, crypt_buf, bytes) < 0) - { + if (qcow2_co_encrypt(bs, host_offset, offset, crypt_buf, bytes) < 0) { ret = -EIO; goto out_unlocked; } @@ -2507,10 +2506,8 @@ static coroutine_fn int qcow2_co_pwritev_task(BlockDriverState *bs, */ if (!merge_cow(offset, bytes, qiov, qiov_offset, l2meta)) { BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); - trace_qcow2_writev_data(qemu_coroutine_self(), - file_cluster_offset + offset_in_cluster); - ret = bdrv_co_pwritev_part(s->data_file, - file_cluster_offset + offset_in_cluster, + trace_qcow2_writev_data(qemu_coroutine_self(), host_offset); + ret = bdrv_co_pwritev_part(s->data_file, host_offset, bytes, qiov, qiov_offset, 0); if (ret < 0) { goto out_unlocked; @@ -2540,7 +2537,7 @@ static coroutine_fn int qcow2_co_pwritev_task_entry(AioTask *task) assert(!t->cluster_type); - return qcow2_co_pwritev_task(t->bs, t->file_cluster_offset, + return qcow2_co_pwritev_task(t->bs, t->host_offset, t->offset, t->bytes, t->qiov, t->qiov_offset, t->l2meta); } @@ -2595,8 +2592,8 @@ static coroutine_fn int qcow2_co_pwritev_part( aio = aio_task_pool_new(QCOW2_MAX_WORKERS); } ret = qcow2_add_task(bs, aio, qcow2_co_pwritev_task_entry, 0, - cluster_offset, offset, cur_bytes, - qiov, qiov_offset, l2meta); + cluster_offset + offset_in_cluster, offset, + cur_bytes, qiov, qiov_offset, l2meta); l2meta = NULL; /* l2meta is consumed by qcow2_co_pwritev_task() */ if (ret < 0) { goto fail_nometa; @@ -4562,7 +4559,7 @@ qcow2_co_pwritev_compressed_part(BlockDriverState *bs, static int coroutine_fn qcow2_co_preadv_compressed(BlockDriverState *bs, - uint64_t file_cluster_offset, + uint64_t cluster_descriptor, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, @@ -4574,8 +4571,8 @@ qcow2_co_preadv_compressed(BlockDriverState *bs, uint8_t *buf, *out_buf; int offset_in_cluster = offset_into_cluster(s, offset); - coffset = file_cluster_offset & s->cluster_offset_mask; - nb_csectors = ((file_cluster_offset >> s->csize_shift) & s->csize_mask) + 1; + coffset = cluster_descriptor & s->cluster_offset_mask; + nb_csectors = ((cluster_descriptor >> s->csize_shift) & s->csize_mask) + 1; csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE - (coffset & ~QCOW2_COMPRESSED_SECTOR_MASK); diff --git a/block/trace-events b/block/trace-events index 9158335061..e1c79a910d 100644 --- a/block/trace-events +++ b/block/trace-events @@ -77,7 +77,7 @@ luring_io_uring_submit(void *s, int ret) "LuringState %p ret %d" luring_resubmit_short_read(void *s, void *luringcb, int nread) "LuringState %p luringcb %p nread %d" # qcow2.c -qcow2_add_task(void *co, void *bs, void *pool, const char *action, int cluster_type, uint64_t file_cluster_offset, uint64_t offset, uint64_t bytes, void *qiov, size_t qiov_offset) "co %p bs %p pool %p: %s: cluster_type %d file_cluster_offset %" PRIu64 " offset %" PRIu64 " bytes %" PRIu64 " qiov %p qiov_offset %zu" +qcow2_add_task(void *co, void *bs, void *pool, const char *action, int cluster_type, uint64_t host_offset, uint64_t offset, uint64_t bytes, void *qiov, size_t qiov_offset) "co %p bs %p pool %p: %s: cluster_type %d file_cluster_offset %" PRIu64 " offset %" PRIu64 " bytes %" PRIu64 " qiov %p qiov_offset %zu" qcow2_writev_start_req(void *co, int64_t offset, int bytes) "co %p offset 0x%" PRIx64 " bytes %d" qcow2_writev_done_req(void *co, int ret) "co %p ret %d" qcow2_writev_start_part(void *co) "co %p" -- 2.11.0