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[PATCH v5 24/31] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2(
From: |
Alberto Garcia |
Subject: |
[PATCH v5 24/31] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2() |
Date: |
Tue, 5 May 2020 19:38:24 +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 <address@hidden>
---
block/qcow2-cluster.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 2283a308d0..4544a40aa0 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1000,6 +1000,24 @@ 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);
+ l2_bitmap &= ~QCOW_OFLAG_SUB_ZERO_RANGE(first_sc, last_sc);
+ set_l2_bitmap(s, l2_slice, l2_index + i, l2_bitmap);
+ }
}
--
2.20.1
- [PATCH v5 11/31] qcow2: Add offset_into_subcluster() and size_to_subclusters(), (continued)
- [PATCH v5 11/31] qcow2: Add offset_into_subcluster() and size_to_subclusters(), Alberto Garcia, 2020/05/05
- [PATCH v5 03/31] qcow2: Add calculate_l2_meta(), Alberto Garcia, 2020/05/05
- [PATCH v5 22/31] qcow2: Add subcluster support to discard_in_l2_slice(), Alberto Garcia, 2020/05/05
- [PATCH v5 18/31] qcow2: Handle QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC, Alberto Garcia, 2020/05/05
- [PATCH v5 01/31] qcow2: Make Qcow2AioTask store the full host offset, Alberto Garcia, 2020/05/05
- [PATCH v5 02/31] qcow2: Convert qcow2_get_cluster_offset() into qcow2_get_host_offset(), Alberto Garcia, 2020/05/05
- [PATCH v5 09/31] qcow2: Add subcluster-related fields to BDRVQcow2State, Alberto Garcia, 2020/05/05
- [PATCH v5 12/31] qcow2: Add l2_entry_size(), Alberto Garcia, 2020/05/05
- [PATCH v5 24/31] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2(),
Alberto Garcia <=
- [PATCH v5 06/31] qcow2: Add get_l2_entry() and set_l2_entry(), Alberto Garcia, 2020/05/05
- [PATCH v5 21/31] qcow2: Add subcluster support to zero_in_l2_slice(), Alberto Garcia, 2020/05/05
- [PATCH v5 27/31] qcow2: Add subcluster support to qcow2_co_pwrite_zeroes(), Alberto Garcia, 2020/05/05
- [PATCH v5 30/31] qcow2: Add subcluster support to qcow2_measure(), Alberto Garcia, 2020/05/05
- [PATCH v5 29/31] qcow2: Assert that expand_zero_clusters_in_l1() does not support subclusters, Alberto Garcia, 2020/05/05
- [PATCH v5 19/31] qcow2: Add subcluster support to calculate_l2_meta(), Alberto Garcia, 2020/05/05