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[RFC,v2,19/26] qcow2: Fix offset calculation in handle_dependencies()

Message ID 299818a13e48bb30ba27bd3afcd3d888c8e053a7.1572125022.git.berto@igalia.com
State New
Headers show
Series Add subcluster allocation to qcow2 | expand

Commit Message

Alberto Garcia Oct. 26, 2019, 9:25 p.m. UTC 
l2meta_cow_start() and l2meta_cow_end() are not necessarily
cluster-aligned if the image has subclusters, so update the
calculation of old_start and old_end to guarantee that no two requests
try to write on the same cluster.

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 block/qcow2-cluster.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
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Patch

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 62f2a9fcc0..fb6cf8df17 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1262,8 +1262,8 @@  static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset,
 
         uint64_t start = guest_offset;
         uint64_t end = start + bytes;
-        uint64_t old_start = l2meta_cow_start(old_alloc);
-        uint64_t old_end = l2meta_cow_end(old_alloc);
+        uint64_t old_start = start_of_cluster(s, l2meta_cow_start(old_alloc));
+        uint64_t old_end = ROUND_UP(l2meta_cow_end(old_alloc), s->cluster_size);
 
         if (end <= old_start || start >= old_end) {
             /* No intersection */