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20209d8d73
pve-qemu-qoup/debian/patches/pve/0048-block-copy-before-write-create-block_copy-bitmap-in-.patch
Thomas Lamprecht 20209d8d73 implement support for backup fleecing 
Excerpt from Fiona's v3 cover-letter [0]:

When a backup for a VM is started, QEMU will install a
"copy-before-write" filter in its block layer. This filter ensures
that upon new guest writes, old data still needed for the backup is
sent to the backup target first. The guest write blocks until this
operation is finished so guest IO to not-yet-backed-up sectors will be
limited by the speed of the backup target.

With backup fleecing, such old data is cached in a fleecing image
rather than sent directly to the backup target. This can help guest IO
performance and even prevent hangs in certain scenarios, at the cost
of requiring more storage space.

With this series it will be possible to enable backup-fleecing via
e.g. `vzdump 123 --fleecing enabled=1,storage=local-lvm` with fleecing
images created on the storage `local-lvm`. The fleecing storage should
be a fast local storage which supports thin-provisioning and discard.
If the storage supports qcow2, that is used as the fleecing image
format. If the underlying file system does not support discard, with
qcow2 and preallocation=off, at least already allocated parts of the
image can be re-used later.

Fleecing images are created by qemu-server via pve-storage and
attached to QEMU before the backup starts, and cleaned up after the
backup finished or failed. The naming schema for fleecing images is
'vm-ID-fleece-N(.FORMAT)'. The allocated images are recorded in the
guest configuration, so that even after a hard failure, clean-up can
be re-attempted. While not too bad, it's a non-trivial amount of code
and I'm not 100% sure about the cost-benefit, so sending those as RFC.

The fleecing image needs to be the exact same size as the source, but
luckily, an explicit size can be specified when attaching a raw image
to QEMU so there are no size issues when using storages that have
coarser allocation/round up. For qcow2, it seems that virtual size can
be nearly arbitrary (i.e. modulo 512 byte granularity) during
allocation.

[0]: https://lists.proxmox.com/pipermail/pve-devel/2024-April/062815.html

Originally-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
2024-04-11 20:05:02 +02:00

374 lines
9.3 KiB
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Raw Blame History

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Date: Thu, 11 Apr 2024 11:29:24 +0200
Subject: [PATCH] block/copy-before-write: create block_copy bitmap in filter
node
Currently block_copy creates copy_bitmap in source node. But that is in
bad relation with .independent_close=true of copy-before-write filter:
source node may be detached and removed before .bdrv_close() handler
called, which should call block_copy_state_free(), which in turn should
remove copy_bitmap.
That's all not ideal: it would be better if internal bitmap of
block-copy object is not attached to any node. But that is not possible
now.
The simplest solution is just create copy_bitmap in filter node, where
anyway two other bitmaps are created.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
block/block-copy.c | 3 +-
block/copy-before-write.c | 2 +-
include/block/block-copy.h | 1 +
tests/qemu-iotests/257.out | 112 ++++++++++++++++++-------------------
4 files changed, 60 insertions(+), 58 deletions(-)
diff --git a/block/block-copy.c b/block/block-copy.c
index e13d7bc6b6..b61685f1a2 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -346,6 +346,7 @@ static int64_t block_copy_calculate_cluster_size(BlockDriverState *target,
}
BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
+ BlockDriverState *copy_bitmap_bs,
const BdrvDirtyBitmap *bitmap,
Error **errp)
{
@@ -360,7 +361,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
return NULL;
}
- copy_bitmap = bdrv_create_dirty_bitmap(source->bs, cluster_size, NULL,
+ copy_bitmap = bdrv_create_dirty_bitmap(copy_bitmap_bs, cluster_size, NULL,
errp);
if (!copy_bitmap) {
return NULL;
diff --git a/block/copy-before-write.c b/block/copy-before-write.c
index 0a219c2b75..d3b95bd600 100644
--- a/block/copy-before-write.c
+++ b/block/copy-before-write.c
@@ -470,7 +470,7 @@ static int cbw_open(BlockDriverState *bs, QDict *options, int flags,
((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
bs->file->bs->supported_zero_flags);
- s->bcs = block_copy_state_new(bs->file, s->target, bitmap, errp);
+ s->bcs = block_copy_state_new(bs->file, s->target, bs, bitmap, errp);
if (!s->bcs) {
error_prepend(errp, "Cannot create block-copy-state: ");
ret = -EINVAL;
diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index 0700953ab8..8b41643bfa 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -25,6 +25,7 @@ typedef struct BlockCopyState BlockCopyState;
typedef struct BlockCopyCallState BlockCopyCallState;
BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
+ BlockDriverState *copy_bitmap_bs,
const BdrvDirtyBitmap *bitmap,
Error **errp);
diff --git a/tests/qemu-iotests/257.out b/tests/qemu-iotests/257.out
index aa76131ca9..c33dd7f3a9 100644
--- a/tests/qemu-iotests/257.out
+++ b/tests/qemu-iotests/257.out
@@ -120,16 +120,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -596,16 +596,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -865,16 +865,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -1341,16 +1341,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -1610,16 +1610,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -2086,16 +2086,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -2355,16 +2355,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -2831,16 +2831,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -3100,16 +3100,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -3576,16 +3576,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -3845,16 +3845,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -4321,16 +4321,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -4590,16 +4590,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
@@ -5066,16 +5066,16 @@ write -P0x67 0x3fe0000 0x20000
"granularity": 65536,
"persistent": false,
"recording": false
- }
- ],
- "drive0": [
+ },
{
"busy": false,
"count": 0,
"granularity": 65536,
"persistent": false,
"recording": false
- },
+ }
+ ],
+ "drive0": [
{
"busy": false,
"count": 458752,
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