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[PATCH v9 25/34] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2(
From: |
Alberto Garcia |
Subject: |
[PATCH v9 25/34] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2() |
Date: |
Sun, 28 Jun 2020 13:02:34 +0200 |
The L2 bitmap needs to be updated after each write to indicate what
new subclusters are now allocated. This needs to happen even if the
cluster was already allocated and the L2 entry was otherwise valid.
In some cases however a write operation doesn't need change the L2
bitmap (because all affected subclusters were already allocated). This
is detected in calculate_l2_meta(), and qcow2_alloc_cluster_link_l2()
is never called in those cases.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
block/qcow2-cluster.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index edfc8ea91c..2276cee6d6 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1061,6 +1061,24 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs,
QCowL2Meta *m)
assert((offset & L2E_OFFSET_MASK) == offset);
set_l2_entry(s, l2_slice, l2_index + i, offset | QCOW_OFLAG_COPIED);
+
+ /* Update bitmap with the subclusters that were just written */
+ if (has_subclusters(s)) {
+ uint64_t l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + i);
+ unsigned written_from = m->cow_start.offset;
+ unsigned written_to = m->cow_end.offset + m->cow_end.nb_bytes ?:
+ m->nb_clusters << s->cluster_bits;
+ int first_sc, last_sc;
+ /* Narrow written_from and written_to down to the current cluster
*/
+ written_from = MAX(written_from, i << s->cluster_bits);
+ written_to = MIN(written_to, (i + 1) << s->cluster_bits);
+ assert(written_from < written_to);
+ first_sc = offset_to_sc_index(s, written_from);
+ last_sc = offset_to_sc_index(s, written_to - 1);
+ l2_bitmap |= QCOW_OFLAG_SUB_ALLOC_RANGE(first_sc, last_sc + 1);
+ l2_bitmap &= ~QCOW_OFLAG_SUB_ZERO_RANGE(first_sc, last_sc + 1);
+ set_l2_bitmap(s, l2_slice, l2_index + i, l2_bitmap);
+ }
}
--
2.20.1
- [PATCH v9 05/34] qcow2: Process QCOW2_CLUSTER_ZERO_ALLOC clusters in handle_copied(), (continued)
- [PATCH v9 05/34] qcow2: Process QCOW2_CLUSTER_ZERO_ALLOC clusters in handle_copied(), Alberto Garcia, 2020/06/28
- [PATCH v9 04/34] qcow2: Split cluster_needs_cow() out of count_cow_clusters(), Alberto Garcia, 2020/06/28
- [PATCH v9 13/34] qcow2: Update get/set_l2_entry() and add get/set_l2_bitmap(), Alberto Garcia, 2020/06/28
- [PATCH v9 24/34] qcow2: Add subcluster support to check_refcounts_l2(), Alberto Garcia, 2020/06/28
- [PATCH v9 19/34] qcow2: Handle QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC, Alberto Garcia, 2020/06/28
- [PATCH v9 09/34] qcow2: Add subcluster-related fields to BDRVQcow2State, Alberto Garcia, 2020/06/28
- [PATCH v9 16/34] qcow2: Add qcow2_cluster_is_allocated(), Alberto Garcia, 2020/06/28
- [PATCH v9 11/34] qcow2: Add offset_into_subcluster() and size_to_subclusters(), Alberto Garcia, 2020/06/28
- [PATCH v9 29/34] qcow2: Add subcluster support to qcow2_measure(), Alberto Garcia, 2020/06/28
- [PATCH v9 22/34] qcow2: Add subcluster support to zero_in_l2_slice(), Alberto Garcia, 2020/06/28
- [PATCH v9 25/34] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2(),
Alberto Garcia <=
- [PATCH v9 01/34] qcow2: Make Qcow2AioTask store the full host offset, Alberto Garcia, 2020/06/28
- [PATCH v9 33/34] qcow2: Assert that expand_zero_clusters_in_l1() does not support subclusters, Alberto Garcia, 2020/06/28
- [PATCH v9 15/34] qcow2: Add qcow2_get_subcluster_range_type(), Alberto Garcia, 2020/06/28
- [PATCH v9 23/34] qcow2: Add subcluster support to discard_in_l2_slice(), Alberto Garcia, 2020/06/28
- [PATCH v9 20/34] qcow2: Add subcluster support to calculate_l2_meta(), Alberto Garcia, 2020/06/28
- [PATCH v9 27/34] qcow2: Add subcluster support to handle_alloc_space(), Alberto Garcia, 2020/06/28
- [PATCH v9 30/34] qcow2: Add prealloc field to QCowL2Meta, Alberto Garcia, 2020/06/28
- [PATCH v9 32/34] qcow2: Allow preallocation and backing files if extended_l2 is set, Alberto Garcia, 2020/06/28
- [PATCH v9 18/34] qcow2: Replace QCOW2_CLUSTER_* with QCOW2_SUBCLUSTER_*, Alberto Garcia, 2020/06/28
- [PATCH v9 14/34] qcow2: Add QCow2SubclusterType and qcow2_get_subcluster_type(), Alberto Garcia, 2020/06/28