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[PATCH v10 25/34] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2
From: |
Alberto Garcia |
Subject: |
[PATCH v10 25/34] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2() |
Date: |
Fri, 3 Jul 2020 17:58:11 +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>
Reviewed-by: Max Reitz <mreitz@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 ea025dc531..5bdbb65e7b 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1062,6 +1062,24 @@ 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 v10 02/34] qcow2: Convert qcow2_get_cluster_offset() into qcow2_get_host_offset(), (continued)
- [PATCH v10 02/34] qcow2: Convert qcow2_get_cluster_offset() into qcow2_get_host_offset(), Alberto Garcia, 2020/07/03
- [PATCH v10 04/34] qcow2: Split cluster_needs_cow() out of count_cow_clusters(), Alberto Garcia, 2020/07/03
- [PATCH v10 11/34] qcow2: Add offset_into_subcluster() and size_to_subclusters(), Alberto Garcia, 2020/07/03
- [PATCH v10 12/34] qcow2: Add l2_entry_size(), Alberto Garcia, 2020/07/03
- [PATCH v10 10/34] qcow2: Add offset_to_sc_index(), Alberto Garcia, 2020/07/03
- [PATCH v10 16/34] qcow2: Add qcow2_cluster_is_allocated(), Alberto Garcia, 2020/07/03
- [PATCH v10 15/34] qcow2: Add qcow2_get_subcluster_range_type(), Alberto Garcia, 2020/07/03
- [PATCH v10 21/34] qcow2: Add subcluster support to qcow2_get_host_offset(), Alberto Garcia, 2020/07/03
- [PATCH v10 25/34] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2(),
Alberto Garcia <=
- [PATCH v10 18/34] qcow2: Replace QCOW2_CLUSTER_* with QCOW2_SUBCLUSTER_*, Alberto Garcia, 2020/07/03
- [PATCH v10 14/34] qcow2: Add QCow2SubclusterType and qcow2_get_subcluster_type(), Alberto Garcia, 2020/07/03
- [PATCH v10 28/34] qcow2: Add subcluster support to qcow2_co_pwrite_zeroes(), Alberto Garcia, 2020/07/03
- [PATCH v10 33/34] qcow2: Assert that expand_zero_clusters_in_l1() does not support subclusters, Alberto Garcia, 2020/07/03
- [PATCH v10 19/34] qcow2: Handle QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC, Alberto Garcia, 2020/07/03
- [PATCH v10 20/34] qcow2: Add subcluster support to calculate_l2_meta(), Alberto Garcia, 2020/07/03
- [PATCH v10 23/34] qcow2: Add subcluster support to discard_in_l2_slice(), Alberto Garcia, 2020/07/03
- [PATCH v10 26/34] qcow2: Clear the L2 bitmap when allocating a compressed cluster, Alberto Garcia, 2020/07/03
- [PATCH v10 22/34] qcow2: Add subcluster support to zero_in_l2_slice(), Alberto Garcia, 2020/07/03