diff options
| author |   Kevin Wolf <kwolf@redhat.com> | 2010-09-01 12:40:52 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2010-09-13 14:34:03 +0200 |
| commit | 2c25b8131631c39145fe1f5b7745943e0e0c0406 (patch) | |
| tree | 925bb1f2b8a3ae58f0389c3890962c648b926582 | |
| parent | 5a0d460c350c58362651458824618cf6b3de3710 (diff) | |
qcow2: Remove unnecessary flush after L2 write
When a new cluster was allocated, we only need a flush after the write to the
L2 table if it was a COW and we need to decrease the refcounts of the old
clusters.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 7ec5e6a4ca43494949465f9f9f3d9e4c7c620503)
| -rw-r--r-- | block/qcow2-cluster.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 166922f8b..f562b1602 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -655,7 +655,7 @@ static int write_l2_entries(BlockDriverState *bs, uint64_t *l2_table, int ret; BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); - ret = bdrv_pwrite_sync(bs->file, l2_offset + start_offset, + ret = bdrv_pwrite(bs->file, l2_offset + start_offset, &l2_table[l2_start_index], len); if (ret < 0) { return ret; @@ -718,9 +718,17 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m) goto err; } - for (i = 0; i < j; i++) - qcow2_free_any_clusters(bs, - be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1); + /* + * If this was a COW, we need to decrease the refcount of the old cluster. + * Also flush bs->file to get the right order for L2 and refcount update. + */ + if (j != 0) { + bdrv_flush(bs->file); + for (i = 0; i < j; i++) { + qcow2_free_any_clusters(bs, + be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1); + } + } ret = 0; err: |