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qemu-kvm/SOURCES/kvm-dirty-bitmap-make-it-po...

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From 4122c0993f5b6de8db0227f5751e1f49e0b4354c Mon Sep 17 00:00:00 2001
From: John Snow <jsnow@redhat.com>
Date: Tue, 20 Nov 2018 18:18:13 +0000
Subject: [PATCH 19/35] dirty-bitmap: make it possible to restore bitmap after
merge
RH-Author: John Snow <jsnow@redhat.com>
Message-id: <20181120181828.15132-10-jsnow@redhat.com>
Patchwork-id: 83057
O-Subject: [RHEL8/rhel qemu-kvm PATCH 09/24] dirty-bitmap: make it possible to restore bitmap after merge
Bugzilla: 1518989
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Add backup parameter to bdrv_merge_dirty_bitmap() to be used then with
bdrv_restore_dirty_bitmap() if it needed to restore the bitmap after
merge operation.
This is needed to implement bitmap merge transaction action in further
commit.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
(cherry picked from commit fa000f2f9fd96a75a0a33d50ead247fce11da92a)
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
block/dirty-bitmap.c | 17 ++++++++++++++---
blockdev.c | 2 +-
include/block/dirty-bitmap.h | 2 +-
include/qemu/hbitmap.h | 25 ++++++++++++++++---------
util/hbitmap.c | 11 ++++++++---
5 files changed, 40 insertions(+), 17 deletions(-)
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 017ee9d..8ac933c 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -314,7 +314,7 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BlockDriverState *bs,
return NULL;
}
- if (!hbitmap_merge(parent->bitmap, successor->bitmap)) {
+ if (!hbitmap_merge(parent->bitmap, successor->bitmap, parent->bitmap)) {
error_setg(errp, "Merging of parent and successor bitmap failed");
return NULL;
}
@@ -791,8 +791,10 @@ int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset)
}
void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
- Error **errp)
+ HBitmap **backup, Error **errp)
{
+ bool ret;
+
/* only bitmaps from one bds are supported */
assert(dest->mutex == src->mutex);
@@ -810,11 +812,20 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
goto out;
}
- if (!hbitmap_merge(dest->bitmap, src->bitmap)) {
+ if (!hbitmap_can_merge(dest->bitmap, src->bitmap)) {
error_setg(errp, "Bitmaps are incompatible and can't be merged");
goto out;
}
+ if (backup) {
+ *backup = dest->bitmap;
+ dest->bitmap = hbitmap_alloc(dest->size, hbitmap_granularity(*backup));
+ ret = hbitmap_merge(*backup, src->bitmap, dest->bitmap);
+ } else {
+ ret = hbitmap_merge(dest->bitmap, src->bitmap, dest->bitmap);
+ }
+ assert(ret);
+
out:
qemu_mutex_unlock(dest->mutex);
}
diff --git a/blockdev.c b/blockdev.c
index 2d86465..a10fbbd 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3077,7 +3077,7 @@ void qmp_x_block_dirty_bitmap_merge(const char *node, const char *dst_name,
return;
}
- bdrv_merge_dirty_bitmap(dst, src, errp);
+ bdrv_merge_dirty_bitmap(dst, src, NULL, errp);
}
BlockDirtyBitmapSha256 *qmp_x_debug_block_dirty_bitmap_sha256(const char *node,
diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index 259bd27..201ff7f 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -71,7 +71,7 @@ void bdrv_dirty_bitmap_set_persistance(BdrvDirtyBitmap *bitmap,
bool persistent);
void bdrv_dirty_bitmap_set_qmp_locked(BdrvDirtyBitmap *bitmap, bool qmp_locked);
void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
- Error **errp);
+ HBitmap **backup, Error **errp);
/* Functions that require manual locking. */
void bdrv_dirty_bitmap_lock(BdrvDirtyBitmap *bitmap);
diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index ddca52c..a7cb780 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -73,16 +73,23 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size);
/**
* hbitmap_merge:
- * @a: The bitmap to store the result in.
- * @b: The bitmap to merge into @a.
- * @return true if the merge was successful,
- * false if it was not attempted.
- *
- * Merge two bitmaps together.
- * A := A (BITOR) B.
- * B is left unmodified.
+ *
+ * Store result of merging @a and @b into @result.
+ * @result is allowed to be equal to @a or @b.
+ *
+ * Return true if the merge was successful,
+ * false if it was not attempted.
+ */
+bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result);
+
+/**
+ * hbitmap_can_merge:
+ *
+ * hbitmap_can_merge(a, b) && hbitmap_can_merge(a, result) is sufficient and
+ * necessary for hbitmap_merge will not fail.
+ *
*/
-bool hbitmap_merge(HBitmap *a, const HBitmap *b);
+bool hbitmap_can_merge(const HBitmap *a, const HBitmap *b);
/**
* hbitmap_empty:
diff --git a/util/hbitmap.c b/util/hbitmap.c
index bcd3040..d5aca51 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -723,6 +723,10 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size)
}
}
+bool hbitmap_can_merge(const HBitmap *a, const HBitmap *b)
+{
+ return (a->size == b->size) && (a->granularity == b->granularity);
+}
/**
* Given HBitmaps A and B, let A := A (BITOR) B.
@@ -731,14 +735,15 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size)
* @return true if the merge was successful,
* false if it was not attempted.
*/
-bool hbitmap_merge(HBitmap *a, const HBitmap *b)
+bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
{
int i;
uint64_t j;
- if ((a->size != b->size) || (a->granularity != b->granularity)) {
+ if (!hbitmap_can_merge(a, b) || !hbitmap_can_merge(a, result)) {
return false;
}
+ assert(hbitmap_can_merge(b, result));
if (hbitmap_count(b) == 0) {
return true;
@@ -750,7 +755,7 @@ bool hbitmap_merge(HBitmap *a, const HBitmap *b)
*/
for (i = HBITMAP_LEVELS - 1; i >= 0; i--) {
for (j = 0; j < a->sizes[i]; j++) {
- a->levels[i][j] |= b->levels[i][j];
+ result->levels[i][j] = a->levels[i][j] | b->levels[i][j];
}
}
--
1.8.3.1
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