diff options
Diffstat (limited to 'block/qcow2-cluster.c')
| -rw-r--r-- | block/qcow2-cluster.c | 26 |
1 files changed, 12 insertions, 14 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 882f50a80b..81cf77d83c 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -697,12 +697,12 @@ err: * m->depends_on is set to NULL and the other fields in m are meaningless. * * If the cluster is newly allocated, m->nb_clusters is set to the number of - * contiguous clusters that have been allocated. This may be 0 if the request - * conflict with another write request in flight; in this case, m->depends_on - * is set and the remaining fields of m are meaningless. + * contiguous clusters that have been allocated. In this case, the other + * fields of m are valid and contain information about the first allocated + * cluster. * - * If m->nb_clusters is non-zero, the other fields of m are valid and contain - * information about the first allocated cluster. + * If the request conflicts with another write request in flight, the coroutine + * is queued and will be reentered when the dependency has completed. * * Return 0 on success and -errno in error cases */ @@ -721,6 +721,7 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, return ret; } +again: nb_clusters = size_to_clusters(s, n_end << 9); nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); @@ -792,12 +793,12 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, } if (nb_clusters == 0) { - /* Set dependency and wait for a callback */ - m->depends_on = old_alloc; - m->nb_clusters = 0; - *num = 0; - - goto out_wait_dependency; + /* Wait for the dependency to complete. We need to recheck + * the free/allocated clusters when we continue. */ + qemu_co_mutex_unlock(&s->lock); + qemu_co_queue_wait(&old_alloc->dependent_requests); + qemu_co_mutex_lock(&s->lock); + goto again; } } } @@ -834,9 +835,6 @@ out: return 0; -out_wait_dependency: - return qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); - fail: qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); fail_put: |