From: Kevin Wolf <kw...@redhat.com>
Instead of expecting a single l2meta, have a list of them. This allows
to still have a single I/O request for the guest data, even though
multiple l2meta may be needed in order to describe both a COW overwrite
and a new cluster allocation (typical sequential write case).
Signed-off-by: Kevin Wolf <kw...@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
block/qcow2-cluster.c | 3 +++
block/qcow2.c | 14 +++++++++++---
block/qcow2.h | 3 +++
3 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 78e7db9..6dc7f7f 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1069,10 +1069,13 @@ static int handle_alloc(BlockDriverState *bs, uint64_t
guest_offset,
int alloc_n_start = offset_into_cluster(s, guest_offset)
>> BDRV_SECTOR_BITS;
int nb_sectors = MIN(requested_sectors, avail_sectors);
+ QCowL2Meta *old_m = *m;
*m = g_malloc0(sizeof(**m));
**m = (QCowL2Meta) {
+ .next = old_m,
+
.alloc_offset = alloc_cluster_offset,
.offset = start_of_cluster(s, guest_offset),
.nb_clusters = nb_clusters,
diff --git a/block/qcow2.c b/block/qcow2.c
index 3f7edf5..7e7d775 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -858,7 +858,9 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState
*bs,
goto fail;
}
- if (l2meta != NULL) {
+ while (l2meta != NULL) {
+ QCowL2Meta *next;
+
ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
if (ret < 0) {
goto fail;
@@ -871,8 +873,9 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState
*bs,
qemu_co_queue_restart_all(&l2meta->dependent_requests);
+ next = l2meta->next;
g_free(l2meta);
- l2meta = NULL;
+ l2meta = next;
}
remaining_sectors -= cur_nr_sectors;
@@ -885,12 +888,17 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState
*bs,
fail:
qemu_co_mutex_unlock(&s->lock);
- if (l2meta != NULL) {
+ while (l2meta != NULL) {
+ QCowL2Meta *next;
+
if (l2meta->nb_clusters != 0) {
QLIST_REMOVE(l2meta, next_in_flight);
}
qemu_co_queue_restart_all(&l2meta->dependent_requests);
+
+ next = l2meta->next;
g_free(l2meta);
+ l2meta = next;
}
qemu_iovec_destroy(&hd_qiov);
diff --git a/block/qcow2.h b/block/qcow2.h
index 32806bd..bf8db2a 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -250,6 +250,9 @@ typedef struct QCowL2Meta
*/
Qcow2COWRegion cow_end;
+ /** Pointer to next L2Meta of the same write request */
+ struct QCowL2Meta *next;
+
QLIST_ENTRY(QCowL2Meta) next_in_flight;
} QCowL2Meta;
--
1.8.1.4
