diff options
| -rw-r--r-- | block/qcow2-cluster.c | 83 | ||||
| -rw-r--r-- | block/qcow2.h | 29 |
2 files changed, 76 insertions, 36 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index d17a37c..94b7f13 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -615,13 +615,41 @@ uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, return cluster_offset; } +static int perform_cow(BlockDriverState *bs, QCowL2Meta *m, Qcow2COWRegion *r) +{ + BDRVQcowState *s = bs->opaque; + int ret; + + if (r->nb_sectors == 0) { + return 0; + } + + qemu_co_mutex_unlock(&s->lock); + ret = copy_sectors(bs, m->offset / BDRV_SECTOR_SIZE, m->alloc_offset, + r->offset / BDRV_SECTOR_SIZE, + r->offset / BDRV_SECTOR_SIZE + r->nb_sectors); + qemu_co_mutex_lock(&s->lock); + + if (ret < 0) { + return ret; + } + + /* + * Before we update the L2 table to actually point to the new cluster, we + * need to be sure that the refcounts have been increased and COW was + * handled. + */ + qcow2_cache_depends_on_flush(s->l2_table_cache); + + return 0; +} + int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m) { BDRVQcowState *s = bs->opaque; int i, j = 0, l2_index, ret; - uint64_t *old_cluster, start_sect, *l2_table; + uint64_t *old_cluster, *l2_table; uint64_t cluster_offset = m->alloc_offset; - bool cow = false; trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters); @@ -631,36 +659,17 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m) old_cluster = g_malloc(m->nb_clusters * sizeof(uint64_t)); /* copy content of unmodified sectors */ - start_sect = m->offset >> 9; - if (m->n_start) { - cow = true; - qemu_co_mutex_unlock(&s->lock); - ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start); - qemu_co_mutex_lock(&s->lock); - if (ret < 0) - goto err; + ret = perform_cow(bs, m, &m->cow_start); + if (ret < 0) { + goto err; } - if (m->nb_available & (s->cluster_sectors - 1)) { - cow = true; - qemu_co_mutex_unlock(&s->lock); - ret = copy_sectors(bs, start_sect, cluster_offset, m->nb_available, - align_offset(m->nb_available, s->cluster_sectors)); - qemu_co_mutex_lock(&s->lock); - if (ret < 0) - goto err; + ret = perform_cow(bs, m, &m->cow_end); + if (ret < 0) { + goto err; } - /* - * Update L2 table. - * - * Before we update the L2 table to actually point to the new cluster, we - * need to be sure that the refcounts have been increased and COW was - * handled. - */ - if (cow) { - qcow2_cache_depends_on_flush(s->l2_table_cache); - } + /* Update L2 table. */ if (qcow2_need_accurate_refcounts(s)) { qcow2_cache_set_dependency(bs, s->l2_table_cache, @@ -957,19 +966,33 @@ again: * * avail_sectors: Number of sectors from the start of the first * newly allocated to the end of the last newly allocated cluster. + * + * nb_sectors: The number of sectors from the start of the first + * newly allocated cluster to the end of the aread that the write + * request actually writes to (excluding COW at the end) */ int requested_sectors = n_end - keep_clusters * s->cluster_sectors; int avail_sectors = nb_clusters << (s->cluster_bits - BDRV_SECTOR_BITS); + int alloc_n_start = keep_clusters == 0 ? n_start : 0; + int nb_sectors = MIN(requested_sectors, avail_sectors); *m = (QCowL2Meta) { .cluster_offset = keep_clusters == 0 ? alloc_cluster_offset : cluster_offset, .alloc_offset = alloc_cluster_offset, .offset = alloc_offset & ~(s->cluster_size - 1), - .n_start = keep_clusters == 0 ? n_start : 0, .nb_clusters = nb_clusters, - .nb_available = MIN(requested_sectors, avail_sectors), + .nb_available = nb_sectors, + + .cow_start = { + .offset = 0, + .nb_sectors = alloc_n_start, + }, + .cow_end = { + .offset = nb_sectors * BDRV_SECTOR_SIZE, + .nb_sectors = avail_sectors - nb_sectors, + }, }; qemu_co_queue_init(&m->dependent_requests); QLIST_INSERT_HEAD(&s->cluster_allocs, m, next_in_flight); diff --git a/block/qcow2.h b/block/qcow2.h index 2a406a7..1106b33 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -196,6 +196,17 @@ typedef struct QCowCreateState { struct QCowAIOCB; +typedef struct Qcow2COWRegion { + /** + * Offset of the COW region in bytes from the start of the first cluster + * touched by the request. + */ + uint64_t offset; + + /** Number of sectors to copy */ + int nb_sectors; +} Qcow2COWRegion; + /* XXX This could be private for qcow2-cluster.c */ typedef struct QCowL2Meta { @@ -209,12 +220,6 @@ typedef struct QCowL2Meta uint64_t alloc_offset; /** - * Number of sectors between the start of the first allocated cluster and - * the area that the guest actually writes to. - */ - int n_start; - - /** * Number of sectors from the start of the first allocated cluster to * the end of the (possibly shortened) request */ @@ -229,6 +234,18 @@ typedef struct QCowL2Meta */ CoQueue dependent_requests; + /** + * The COW Region between the start of the first allocated cluster and the + * area the guest actually writes to. + */ + Qcow2COWRegion cow_start; + + /** + * The COW Region between the area the guest actually writes to and the + * end of the last allocated cluster. + */ + Qcow2COWRegion cow_end; + QLIST_ENTRY(QCowL2Meta) next_in_flight; } QCowL2Meta; |