implement support for backup fleecing

[pve-qemu.git] / debian / patches / pve / 0047-block-copy-before-write-support-unligned-snapshot-di.patch

diff --git a/debian/patches/pve/0047-block-copy-before-write-support-unligned-snapshot-di.patch b/debian/patches/pve/0047-block-copy-before-write-support-unligned-snapshot-di.patch
new file mode 100644 (file)
index 0000000..4656750
--- /dev/null
+++ b/debian/patches/pve/0047-block-copy-before-write-support-unligned-snapshot-di.patch
@@ -0,0 +1,48 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
+Date: Thu, 11 Apr 2024 11:29:23 +0200
+Subject: [PATCH] block/copy-before-write: support unligned snapshot-discard
+
+First thing that crashes on unligned access here is
+bdrv_reset_dirty_bitmap(). Correct way is to align-down the
+snapshot-discard request.
+
+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/copy-before-write.c | 16 +++++++++++++---
+ 1 file changed, 13 insertions(+), 3 deletions(-)
+
+diff --git a/block/copy-before-write.c b/block/copy-before-write.c
+index a2dddf6f57..0a219c2b75 100644
+--- a/block/copy-before-write.c
++++ b/block/copy-before-write.c
+@@ -325,14 +325,24 @@ static int coroutine_fn GRAPH_RDLOCK
+ cbw_co_pdiscard_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes)
+ {
+     BDRVCopyBeforeWriteState *s = bs->opaque;
++    uint32_t cluster_size = block_copy_cluster_size(s->bcs);
++    int64_t aligned_offset = QEMU_ALIGN_UP(offset, cluster_size);
++    int64_t aligned_end = QEMU_ALIGN_DOWN(offset + bytes, cluster_size);
++    int64_t aligned_bytes;
++
++    if (aligned_end <= aligned_offset) {
++        return 0;
++    }
++    aligned_bytes = aligned_end - aligned_offset;
+ 
+     WITH_QEMU_LOCK_GUARD(&s->lock) {
+-        bdrv_reset_dirty_bitmap(s->access_bitmap, offset, bytes);
++        bdrv_reset_dirty_bitmap(s->access_bitmap, aligned_offset,
++                                aligned_bytes);
+     }
+ 
+-    block_copy_reset(s->bcs, offset, bytes);
++    block_copy_reset(s->bcs, aligned_offset, aligned_bytes);
+ 
+-    return bdrv_co_pdiscard(s->target, offset, bytes);
++    return bdrv_co_pdiscard(s->target, aligned_offset, aligned_bytes);
+ }
+ 
+ static void cbw_refresh_filename(BlockDriverState *bs)