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https://gitlab.com/qemu-project/qemu
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block/qcow2: refactor qcow2_co_preadv_part
Further patch will run partial requests of iterations of qcow2_co_preadv in parallel for performance reasons. To prepare for this, separate part which may be parallelized into separate function (qcow2_co_preadv_task). While being here, also separate encrypted clusters reading to own function, like it is done for compressed reading. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20190916175324.18478-4-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
parent
6e9b225f73
commit
88f468e546
1 changed files with 113 additions and 96 deletions
209
block/qcow2.c
209
block/qcow2.c
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@ -1972,17 +1972,117 @@ out:
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return ret;
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}
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static coroutine_fn int
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qcow2_co_preadv_encrypted(BlockDriverState *bs,
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uint64_t file_cluster_offset,
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uint64_t offset,
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uint64_t bytes,
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QEMUIOVector *qiov,
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uint64_t qiov_offset)
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{
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int ret;
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BDRVQcow2State *s = bs->opaque;
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uint8_t *buf;
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assert(bs->encrypted && s->crypto);
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assert(bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
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/*
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* For encrypted images, read everything into a temporary
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* contiguous buffer on which the AES functions can work.
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* Also, decryption in a separate buffer is better as it
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* prevents the guest from learning information about the
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* encrypted nature of the virtual disk.
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*/
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buf = qemu_try_blockalign(s->data_file->bs, bytes);
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if (buf == NULL) {
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return -ENOMEM;
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}
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BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
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ret = bdrv_co_pread(s->data_file,
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file_cluster_offset + offset_into_cluster(s, offset),
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bytes, buf, 0);
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if (ret < 0) {
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goto fail;
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}
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assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
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assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
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if (qcow2_co_decrypt(bs,
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file_cluster_offset + offset_into_cluster(s, offset),
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offset, buf, bytes) < 0)
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{
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ret = -EIO;
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goto fail;
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}
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qemu_iovec_from_buf(qiov, qiov_offset, buf, bytes);
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fail:
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qemu_vfree(buf);
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return ret;
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}
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static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs,
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QCow2ClusterType cluster_type,
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uint64_t file_cluster_offset,
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uint64_t offset, uint64_t bytes,
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QEMUIOVector *qiov,
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size_t qiov_offset)
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{
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BDRVQcow2State *s = bs->opaque;
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int offset_in_cluster = offset_into_cluster(s, offset);
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switch (cluster_type) {
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case QCOW2_CLUSTER_ZERO_PLAIN:
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case QCOW2_CLUSTER_ZERO_ALLOC:
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/* Both zero types are handled in qcow2_co_preadv_part */
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g_assert_not_reached();
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case QCOW2_CLUSTER_UNALLOCATED:
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assert(bs->backing); /* otherwise handled in qcow2_co_preadv_part */
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BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
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return bdrv_co_preadv_part(bs->backing, offset, bytes,
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qiov, qiov_offset, 0);
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case QCOW2_CLUSTER_COMPRESSED:
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return qcow2_co_preadv_compressed(bs, file_cluster_offset,
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offset, bytes, qiov, qiov_offset);
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case QCOW2_CLUSTER_NORMAL:
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if ((file_cluster_offset & 511) != 0) {
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return -EIO;
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}
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if (bs->encrypted) {
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return qcow2_co_preadv_encrypted(bs, file_cluster_offset,
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offset, bytes, qiov, qiov_offset);
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}
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BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
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return bdrv_co_preadv_part(s->data_file,
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file_cluster_offset + offset_in_cluster,
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bytes, qiov, qiov_offset, 0);
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default:
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g_assert_not_reached();
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}
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g_assert_not_reached();
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}
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static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs,
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uint64_t offset, uint64_t bytes,
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QEMUIOVector *qiov,
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size_t qiov_offset, int flags)
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{
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BDRVQcow2State *s = bs->opaque;
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int offset_in_cluster;
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int ret;
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unsigned int cur_bytes; /* number of bytes in current iteration */
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uint64_t cluster_offset = 0;
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uint8_t *cluster_data = NULL;
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while (bytes != 0) {
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@ -1997,112 +2097,29 @@ static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs,
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ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset);
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qemu_co_mutex_unlock(&s->lock);
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if (ret < 0) {
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goto fail;
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return ret;
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}
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offset_in_cluster = offset_into_cluster(s, offset);
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switch (ret) {
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case QCOW2_CLUSTER_UNALLOCATED:
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if (bs->backing) {
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BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
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ret = bdrv_co_preadv_part(bs->backing, offset, cur_bytes,
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qiov, qiov_offset, 0);
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if (ret < 0) {
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goto fail;
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}
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} else {
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/* Note: in this case, no need to wait */
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qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
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}
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break;
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case QCOW2_CLUSTER_ZERO_PLAIN:
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case QCOW2_CLUSTER_ZERO_ALLOC:
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if (ret == QCOW2_CLUSTER_ZERO_PLAIN ||
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ret == QCOW2_CLUSTER_ZERO_ALLOC ||
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(ret == QCOW2_CLUSTER_UNALLOCATED && !bs->backing))
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{
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qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
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break;
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case QCOW2_CLUSTER_COMPRESSED:
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ret = qcow2_co_preadv_compressed(bs, cluster_offset,
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offset, cur_bytes,
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qiov, qiov_offset);
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} else {
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ret = qcow2_co_preadv_task(bs, ret,
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cluster_offset, offset, cur_bytes,
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qiov, qiov_offset);
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if (ret < 0) {
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goto fail;
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return ret;
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}
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break;
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case QCOW2_CLUSTER_NORMAL:
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if ((cluster_offset & 511) != 0) {
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ret = -EIO;
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goto fail;
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}
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if (bs->encrypted) {
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assert(s->crypto);
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/*
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* For encrypted images, read everything into a temporary
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* contiguous buffer on which the AES functions can work.
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*/
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if (!cluster_data) {
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cluster_data =
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qemu_try_blockalign(s->data_file->bs,
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QCOW_MAX_CRYPT_CLUSTERS
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* s->cluster_size);
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if (cluster_data == NULL) {
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ret = -ENOMEM;
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goto fail;
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}
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}
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assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
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BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
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ret = bdrv_co_pread(s->data_file,
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cluster_offset + offset_in_cluster,
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cur_bytes, cluster_data, 0);
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if (ret < 0) {
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goto fail;
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}
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assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
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assert(QEMU_IS_ALIGNED(cur_bytes, BDRV_SECTOR_SIZE));
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if (qcow2_co_decrypt(bs, cluster_offset + offset_in_cluster,
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offset,
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cluster_data, cur_bytes) < 0) {
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ret = -EIO;
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goto fail;
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}
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qemu_iovec_from_buf(qiov, qiov_offset, cluster_data, cur_bytes);
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} else {
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BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
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ret = bdrv_co_preadv_part(s->data_file,
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cluster_offset + offset_in_cluster,
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cur_bytes, qiov, qiov_offset, 0);
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if (ret < 0) {
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goto fail;
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}
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}
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break;
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default:
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g_assert_not_reached();
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ret = -EIO;
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goto fail;
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}
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bytes -= cur_bytes;
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offset += cur_bytes;
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qiov_offset += cur_bytes;
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}
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ret = 0;
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fail:
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qemu_vfree(cluster_data);
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return ret;
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return 0;
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}
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/* Check if it's possible to merge a write request with the writing of
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