diff options
Diffstat (limited to 'block/qcow2-cluster.c')
| -rw-r--r-- | block/qcow2-cluster.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index dec0af673f..d23d5b3aff 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -611,12 +611,12 @@ static int write_l2_entries(BDRVQcowState *s, uint64_t *l2_table, return 0; } -int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, uint64_t cluster_offset, - QCowL2Meta *m) +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_offset, *l2_table; + uint64_t cluster_offset = m->cluster_offset; if (m->nb_clusters == 0) return 0; @@ -677,16 +677,22 @@ err: /* * alloc_cluster_offset * - * For a given offset of the disk image, return cluster offset in - * qcow2 file. - * + * For a given offset of the disk image, return cluster offset in qcow2 file. * If the offset is not found, allocate a new cluster. * - * Return the cluster offset if successful, - * Return 0, otherwise. + * If the cluster was already allocated, m->nb_clusters is set to 0, + * 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. * + * If m->nb_clusters is non-zero, the other fields of m are valid and contain + * information about the first allocated cluster. + * + * Return 0 on success and -errno in error cases */ - uint64_t qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, int n_start, int n_end, @@ -700,7 +706,7 @@ uint64_t qcow2_alloc_cluster_offset(BlockDriverState *bs, ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index); if (ret < 0) { - return 0; + return ret; } nb_clusters = size_to_clusters(s, n_end << 9); @@ -717,6 +723,7 @@ uint64_t qcow2_alloc_cluster_offset(BlockDriverState *bs, cluster_offset &= ~QCOW_OFLAG_COPIED; m->nb_clusters = 0; + m->depends_on = NULL; goto out; } @@ -795,10 +802,11 @@ uint64_t qcow2_alloc_cluster_offset(BlockDriverState *bs, out: m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end); + m->cluster_offset = cluster_offset; *num = m->nb_available - n_start; - return cluster_offset; + return 0; } static int decompress_buffer(uint8_t *out_buf, int out_buf_size, |