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[Qemu-devel] [RFC PATCH v2 15/23] qcow2: Allow requests with multiple l2
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [RFC PATCH v2 15/23] qcow2: Allow requests with multiple l2metas |
Date: |
Wed, 13 Feb 2013 14:22:05 +0100 |
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 <address@hidden>
---
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 9e6b746..645ea25 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1057,12 +1057,15 @@ 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;
*host_offset = alloc_cluster_offset;
*m = g_malloc0(sizeof(**m));
**m = (QCowL2Meta) {
+ .next = old_m,
+
.alloc_offset = *host_offset,
.offset = start_of_cluster(s, guest_offset),
.nb_clusters = nb_clusters,
diff --git a/block/qcow2.c b/block/qcow2.c
index 971dd42..345487e 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -824,7 +824,9 @@ 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;
@@ -837,8 +839,9 @@ 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;
@@ -851,12 +854,17 @@ 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 bfdf71d..9b16538 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -246,6 +246,9 @@ 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;
--
1.7.6.5
- Re: [Qemu-devel] [RFC PATCH v2 03/23] qcow2: Change handle_dependency to byte granularity, (continued)
[Qemu-devel] [RFC PATCH v2 05/23] qcow2: Factor out handle_alloc(), Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 04/23] qcow2: Decouple cluster allocation from cluster reuse code, Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 09/23] qcow2: Clean up handle_alloc(), Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 08/23] qcow2: Finalise interface of handle_alloc(), Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 07/23] qcow2: handle_alloc(): Get rid of keep_clusters parameter, Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 12/23] qcow2: handle_copied(): Get rid of keep_clusters parameter, Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 11/23] qcow2: handle_copied(): Get rid of nb_clusters parameter, Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 06/23] qcow2: handle_alloc(): Get rid of nb_clusters parameter, Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 15/23] qcow2: Allow requests with multiple l2metas,
Kevin Wolf <=
[Qemu-devel] [RFC PATCH v2 10/23] qcow2: Factor out handle_copied(), Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 13/23] qcow2: handle_copied(): Implement non-zero host_offset, Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 16/23] qcow2: Reading from areas not in L2 tables yet, Kevin Wolf, 2013/02/13
[Qemu-devel] [RFC PATCH v2 18/23] qcow2: Delay the COW, Kevin Wolf, 2013/02/13