diff options
author | Max Reitz <mreitz@redhat.com> | 2015-02-06 09:39:16 -0500 |
---|---|---|
committer | Kevin Wolf <kwolf@redhat.com> | 2015-02-06 17:24:22 +0100 |
commit | 8c44dfbc62a50a8bc4113f199b8662861f757591 (patch) | |
tree | 9377fcba318699096b9e3e1a7e8a97ff5bde98b9 /block/qcow2-refcount.c | |
parent | 8e8cb375e0964b4ed099cb8563029028db26a834 (diff) |
qcow2: Rewrite qcow2_alloc_bytes()
qcow2_alloc_bytes() is a function with insufficient error handling and
an unnecessary goto. This patch rewrites it.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/qcow2-refcount.c')
-rw-r--r-- | block/qcow2-refcount.c | 78 |
1 files changed, 39 insertions, 39 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 9afdb40b40..9b80ca79ea 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -759,54 +759,54 @@ int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) { BDRVQcowState *s = bs->opaque; - int64_t offset, cluster_offset; - int free_in_cluster; + int64_t offset; + size_t free_in_cluster; + int ret; BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); assert(size > 0 && size <= s->cluster_size); - if (s->free_byte_offset == 0) { - offset = qcow2_alloc_clusters(bs, s->cluster_size); - if (offset < 0) { - return offset; + assert(!s->free_byte_offset || offset_into_cluster(s, s->free_byte_offset)); + + offset = s->free_byte_offset; + + if (offset) { + int refcount = qcow2_get_refcount(bs, offset >> s->cluster_bits); + if (refcount < 0) { + return refcount; } - s->free_byte_offset = offset; - } - redo: - free_in_cluster = s->cluster_size - - offset_into_cluster(s, s->free_byte_offset); - if (size <= free_in_cluster) { - /* enough space in current cluster */ - offset = s->free_byte_offset; - s->free_byte_offset += size; - free_in_cluster -= size; - if (free_in_cluster == 0) - s->free_byte_offset = 0; - if (offset_into_cluster(s, offset) != 0) - qcow2_update_cluster_refcount(bs, offset >> s->cluster_bits, 1, - QCOW2_DISCARD_NEVER); - } else { - offset = qcow2_alloc_clusters(bs, s->cluster_size); - if (offset < 0) { - return offset; + + if (refcount == 0xffff) { + offset = 0; } - cluster_offset = start_of_cluster(s, s->free_byte_offset); - if ((cluster_offset + s->cluster_size) == offset) { - /* we are lucky: contiguous data */ - offset = s->free_byte_offset; - qcow2_update_cluster_refcount(bs, offset >> s->cluster_bits, 1, - QCOW2_DISCARD_NEVER); - s->free_byte_offset += size; - } else { - s->free_byte_offset = offset; - goto redo; + } + + free_in_cluster = s->cluster_size - offset_into_cluster(s, offset); + if (!offset || free_in_cluster < size) { + int64_t new_cluster = alloc_clusters_noref(bs, s->cluster_size); + if (new_cluster < 0) { + return new_cluster; + } + + if (!offset || ROUND_UP(offset, s->cluster_size) != new_cluster) { + offset = new_cluster; } } - /* The cluster refcount was incremented, either by qcow2_alloc_clusters() - * or explicitly by qcow2_update_cluster_refcount(). Refcount blocks must - * be flushed before the caller's L2 table updates. - */ + assert(offset); + ret = update_refcount(bs, offset, size, 1, QCOW2_DISCARD_NEVER); + if (ret < 0) { + return ret; + } + + /* The cluster refcount was incremented; refcount blocks must be flushed + * before the caller's L2 table updates. */ qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); + + s->free_byte_offset = offset + size; + if (!offset_into_cluster(s, s->free_byte_offset)) { + s->free_byte_offset = 0; + } + return offset; } |