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[PATCH 3/7] qcow2: zeroize the entire cluster when there're no non-zero
From: |
Andrey Drobyshev |
Subject: |
[PATCH 3/7] qcow2: zeroize the entire cluster when there're no non-zero subclusters |
Date: |
Sat, 21 Oct 2023 00:56:18 +0300 |
When zeroizing the last non-zero subclusters within single cluster, it
makes sense to go zeroize the entire cluster and go down zero_in_l2_slice()
path right away. That way we'd also update the corresponding refcount
table.
Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
---
block/qcow2-cluster.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 8801856b93..7c6fa5524c 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -2145,7 +2145,7 @@ zero_in_l2_slice(BlockDriverState *bs, uint64_t offset,
static int coroutine_fn GRAPH_RDLOCK
zero_l2_subclusters(BlockDriverState *bs, uint64_t offset,
- unsigned nb_subclusters)
+ unsigned nb_subclusters, int flags)
{
BDRVQcow2State *s = bs->opaque;
uint64_t new_l2_bitmap;
@@ -2161,6 +2161,17 @@ zero_l2_subclusters(BlockDriverState *bs, uint64_t
offset,
new_l2_bitmap |= QCOW_OFLAG_SUB_ZERO_RANGE(sc, sc + nb_subclusters);
new_l2_bitmap &= ~QCOW_OFLAG_SUB_ALLOC_RANGE(sc, sc + nb_subclusters);
+ /*
+ * If there're no non-zero subclusters left, we might as well zeroize
+ * the entire cluster. That way we'd also update the refcount table.
+ */
+ if ((new_l2_bitmap & QCOW_L2_BITMAP_ALL_ZEROES) ==
+ QCOW_L2_BITMAP_ALL_ZEROES) {
+ qcow2_cache_put(s->l2_table_cache, (void **) &scri.l2_slice);
+ return zero_in_l2_slice(bs, QEMU_ALIGN_DOWN(offset, s->cluster_size),
+ 1, flags);
+ }
+
if (new_l2_bitmap != scri.l2_bitmap) {
set_l2_bitmap(s, scri.l2_slice, scri.l2_index, new_l2_bitmap);
qcow2_cache_entry_mark_dirty(s->l2_table_cache, scri.l2_slice);
@@ -2221,7 +2232,7 @@ int coroutine_fn
qcow2_subcluster_zeroize(BlockDriverState *bs, uint64_t offset,
if (head) {
ret = zero_l2_subclusters(bs, offset - head,
- size_to_subclusters(s, head));
+ size_to_subclusters(s, head), flags);
if (ret < 0) {
goto fail;
}
@@ -2242,7 +2253,8 @@ int coroutine_fn
qcow2_subcluster_zeroize(BlockDriverState *bs, uint64_t offset,
}
if (tail) {
- ret = zero_l2_subclusters(bs, end_offset, size_to_subclusters(s,
tail));
+ ret = zero_l2_subclusters(bs, end_offset,
+ size_to_subclusters(s, tail), flags);
if (ret < 0) {
goto fail;
}
--
2.39.3
- [PATCH 0/7] qcow2: make subclusters discardable, Andrey Drobyshev, 2023/10/20
- [PATCH 3/7] qcow2: zeroize the entire cluster when there're no non-zero subclusters,
Andrey Drobyshev <=
- [PATCH 5/7] qcow2: zero_l2_subclusters: fall through to discard operation when requested, Andrey Drobyshev, 2023/10/20
- [PATCH 7/7] iotests/271: check disk usage on subcluster-based discard/unmap, Andrey Drobyshev, 2023/10/20
- [PATCH 2/7] qcow2: add get_sc_range_info() helper for working with subcluster ranges, Andrey Drobyshev, 2023/10/20
- [PATCH 6/7] iotests/common.rc: add disk_usage function, Andrey Drobyshev, 2023/10/20
- [PATCH 4/7] qcow2: make subclusters discardable, Andrey Drobyshev, 2023/10/20