diff options
| -rw-r--r-- | block/qcow2-cluster.c | 2 | ||||
| -rw-r--r-- | block/qcow2.c | 6 | ||||
| -rw-r--r-- | block/qcow2.h | 8 |
3 files changed, 15 insertions, 1 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 9d349d61c6..fd506b4cb3 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1067,7 +1067,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m) set_l2_entry(s, l2_slice, l2_index + i, offset | QCOW_OFLAG_COPIED); /* Update bitmap with the subclusters that were just written */ - if (has_subclusters(s)) { + if (has_subclusters(s) && !m->prealloc) { uint64_t l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + i); unsigned written_from = m->cow_start.offset; unsigned written_to = m->cow_end.offset + m->cow_end.nb_bytes ?: diff --git a/block/qcow2.c b/block/qcow2.c index 54c9b7c119..7c03d41170 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2096,6 +2096,7 @@ static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs, QCowL2Meta *next; if (link_l2) { + assert(!l2meta->prealloc); ret = qcow2_alloc_cluster_link_l2(bs, l2meta); if (ret) { goto out; @@ -3130,6 +3131,7 @@ static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset, while (meta) { QCowL2Meta *next = meta->next; + meta->prealloc = true; ret = qcow2_alloc_cluster_link_l2(bs, meta); if (ret < 0) { @@ -4217,6 +4219,7 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, int64_t clusters_allocated; int64_t old_file_size, last_cluster, new_file_size; uint64_t nb_new_data_clusters, nb_new_l2_tables; + bool subclusters_need_allocation = false; /* With a data file, preallocation means just allocating the metadata * and forwarding the truncate request to the data file */ @@ -4298,6 +4301,8 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, BDRV_REQ_ZERO_WRITE, NULL); if (ret >= 0) { flags &= ~BDRV_REQ_ZERO_WRITE; + /* Ensure that we read zeroes and not backing file data */ + subclusters_need_allocation = true; } } else { ret = -1; @@ -4336,6 +4341,7 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, .offset = nb_clusters << s->cluster_bits, .nb_bytes = 0, }, + .prealloc = !subclusters_need_allocation, }; qemu_co_queue_init(&allocation.dependent_requests); diff --git a/block/qcow2.h b/block/qcow2.h index 4ef4ae4ab0..f3499e53bf 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -464,6 +464,14 @@ typedef struct QCowL2Meta bool skip_cow; /** + * Indicates that this is not a normal write request but a preallocation. + * If the image has extended L2 entries this means that no new individual + * subclusters will be marked as allocated in the L2 bitmap (but any + * existing contents of that bitmap will be kept). + */ + bool prealloc; + + /** * The I/O vector with the data from the actual guest write request. * If non-NULL, this is meant to be merged together with the data * from @cow_start and @cow_end into one single write operation. |