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qcow2: Allocate l2meta only for cluster allocations

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Even for writes to already allocated clusters, an l2meta is allocated,
though it stays effectively unused. After this patch, only allocating
requests still have one. Each l2meta now describes an in-flight request
that writes to clusters that are not yet hooked up in the L2 table.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf committed 2012-12-13 15:37:59 +01:00
1 parent 060bee8943
commit f50f88b9fe
3 files changed
+31 -31
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block/qcow2.c
+17 -15
View File
@@ -787,8 +787,7 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
while (remaining_sectors != 0) {
l2meta = g_malloc0(sizeof(*l2meta));
qemu_co_queue_init(&l2meta->dependent_requests);
l2meta = NULL;
trace_qcow2_writev_start_part(qemu_coroutine_self());
index_in_cluster = sector_num & (s->cluster_sectors - 1);
@@ -799,7 +798,7 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
}
ret = qcow2_alloc_cluster_offset(bs, sector_num << 9,
index_in_cluster, n_end, &cur_nr_sectors, &cluster_offset, l2meta);
index_in_cluster, n_end, &cur_nr_sectors, &cluster_offset, &l2meta);
if (ret < 0) {
goto fail;
}
@@ -845,14 +844,16 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
goto fail;
}
ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
if (ret < 0) {
goto fail;
}
if (l2meta != NULL) {
ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
if (ret < 0) {
goto fail;
}
run_dependent_requests(s, l2meta);
g_free(l2meta);
l2meta = NULL;
run_dependent_requests(s, l2meta);
g_free(l2meta);
l2meta = NULL;
}
remaining_sectors -= cur_nr_sectors;
sector_num += cur_nr_sectors;
@@ -1134,11 +1135,10 @@ static int preallocate(BlockDriverState *bs)
uint64_t host_offset = 0;
int num;
int ret;
QCowL2Meta meta;
QCowL2Meta *meta;
nb_sectors = bdrv_getlength(bs) >> 9;
offset = 0;
qemu_co_queue_init(&meta.dependent_requests);
while (nb_sectors) {
num = MIN(nb_sectors, INT_MAX >> 9);
@@ -1148,15 +1148,17 @@ static int preallocate(BlockDriverState *bs)
return ret;
}
ret = qcow2_alloc_cluster_link_l2(bs, &meta);
ret = qcow2_alloc_cluster_link_l2(bs, meta);
if (ret < 0) {
qcow2_free_any_clusters(bs, meta.alloc_offset, meta.nb_clusters);
qcow2_free_any_clusters(bs, meta->alloc_offset, meta->nb_clusters);
return ret;
}
/* There are no dependent requests, but we need to remove our request
* from the list of in-flight requests */
run_dependent_requests(bs->opaque, &meta);
if (meta != NULL) {
run_dependent_requests(bs->opaque, meta);
}
/* TODO Preallocate data if requested */