From: Kevin Wolf <kw...@redhat.com>
This makes handle_alloc() and handle_copied() return byte-granularity
host offsets instead of returning always the cluster start. This is
required so that qcow2_alloc_cluster_offset() can stop aligning
everything to cluster boundaries.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
block/qcow2-cluster.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 239a997..4f43d41 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -817,7 +817,9 @@ static int handle_dependencies(BlockDriverState *bs,
uint64_t guest_offset,
* *host_offset is not zero, only physically contiguous clusters beginning at
* this host offset are counted.
*
- * Note that guest_offset may not be cluster aligned.
+ * Note that guest_offset may not be cluster aligned. In this case, the
+ * returned *host_offset points to exact byte referenced by guest_offset and
+ * therefore isn't cluster aligned as well.
*
* Returns:
* 0: if no allocated clusters are available at the given offset.
@@ -845,6 +847,9 @@ static int handle_copied(BlockDriverState *bs, uint64_t
guest_offset,
trace_qcow2_handle_copied(qemu_coroutine_self(), guest_offset,
*host_offset,
*bytes);
+ assert(*host_offset == 0 || offset_into_cluster(s, guest_offset)
+ == offset_into_cluster(s, *host_offset));
+
/*
* Calculate the number of clusters to look for. We stop at L2 table
* boundaries to keep things simple.
@@ -903,7 +908,8 @@ out:
/* Only return a host offset if we actually made progress. Otherwise we
* would make requirements for handle_alloc() that it can't fulfill */
if (ret) {
- *host_offset = cluster_offset & L2E_OFFSET_MASK;
+ *host_offset = (cluster_offset & L2E_OFFSET_MASK)
+ + offset_into_cluster(s, guest_offset);
}
return ret;
@@ -961,7 +967,9 @@ static int do_alloc_cluster_offset(BlockDriverState *bs,
uint64_t guest_offset,
* copy on write. If *host_offset is non-zero, clusters are only allocated if
* the new allocation can match the specified host offset.
*
- * Note that guest_offset may not be cluster aligned.
+ * Note that guest_offset may not be cluster aligned. In this case, the
+ * returned *host_offset points to exact byte referenced by guest_offset and
+ * therefore isn't cluster aligned as well.
*
* Returns:
* 0: if no clusters could be allocated. *bytes is set to 0,
@@ -1026,7 +1034,7 @@ static int handle_alloc(BlockDriverState *bs, uint64_t
guest_offset,
}
/* Allocate, if necessary at a given offset in the image file */
- alloc_cluster_offset = *host_offset;
+ alloc_cluster_offset = start_of_cluster(s, *host_offset);
ret = do_alloc_cluster_offset(bs, guest_offset, &alloc_cluster_offset,
&nb_clusters);
if (ret < 0) {
@@ -1062,12 +1070,10 @@ static int handle_alloc(BlockDriverState *bs, uint64_t
guest_offset,
>> BDRV_SECTOR_BITS;
int nb_sectors = MIN(requested_sectors, avail_sectors);
- *host_offset = alloc_cluster_offset;
-
*m = g_malloc0(sizeof(**m));
**m = (QCowL2Meta) {
- .alloc_offset = *host_offset,
+ .alloc_offset = alloc_cluster_offset,
.offset = start_of_cluster(s, guest_offset),
.nb_clusters = nb_clusters,
.nb_available = nb_sectors,
@@ -1084,6 +1090,7 @@ static int handle_alloc(BlockDriverState *bs, uint64_t
guest_offset,
qemu_co_queue_init(&(*m)->dependent_requests);
QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight);
+ *host_offset = alloc_cluster_offset + offset_into_cluster(s, guest_offset);
*bytes = MIN(*bytes, (nb_sectors * BDRV_SECTOR_SIZE)
- offset_into_cluster(s, guest_offset));
assert(*bytes != 0);
@@ -1186,7 +1193,7 @@ again:
nb_clusters -= keep_clusters;
if (!*host_offset) {
- *host_offset = cluster_offset;
+ *host_offset = start_of_cluster(s, cluster_offset);
}
} else if (cur_bytes == 0) {
keep_clusters = 0;
@@ -1228,7 +1235,7 @@ again:
}
if (!*host_offset) {
- *host_offset = cluster_offset;
+ *host_offset = start_of_cluster(s, cluster_offset);
}
nb_clusters = size_to_clusters(s, cur_bytes + offset_into_cluster(s,
offset));
--
1.8.1.4
