>Use local variable to bdrv_pwrite_sync L1 table,
>needless to make conversion of cached L1 table between
>big-endian and host style.
>
>Signed-off-by: Zhang Haoyu <zhan...@sangfor.com>
>Reviewed-by: Max Reitz <mre...@redhat.com>
>---
>v2 -> v3:
> - replace g_try_malloc0 with qemu_try_blockalign
> - copy the latest local L1 table back to s->l1_table
> after successfully bdrv_pwrite_sync L1 table
>
>v1 -> v2:
> - remove the superflous assignment, l1_table = NULL;
> - replace 512 with BDRV_SECTOR_SIZE, and align_offset with ROUND_UP
> - remove needless check of if (l1_table) before g_free(l1_table)
>
> block/qcow2-refcount.c | 25 +++++++++----------------
> 1 file changed, 9 insertions(+), 16 deletions(-)
>
>diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
>index 2bcaaf9..bceadce 100644
>--- a/block/qcow2-refcount.c
>+++ b/block/qcow2-refcount.c
>@@ -881,14 +881,17 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
> {
> BDRVQcowState *s = bs->opaque;
> uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2;
>- bool l1_allocated = false;
> int64_t old_offset, old_l2_offset;
> int i, j, l1_modified = 0, nb_csectors, refcount;
> int ret;
>
> l2_table = NULL;
>- l1_table = NULL;
> l1_size2 = l1_size * sizeof(uint64_t);
>+ l1_table = qemu_try_blockalign(bs->file, l1_size2);
>+ if (l1_size2 && l1_table == NULL) {
>+ ret = -ENOMEM;
>+ goto fail;
>+ }
>
> s->cache_discards = true;
>
>@@ -896,13 +899,6 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
> * l1_table_offset when it is the current s->l1_table_offset! Be careful
> * when changing this! */
> if (l1_table_offset != s->l1_table_offset) {
>- l1_table = g_try_malloc0(align_offset(l1_size2, 512));
>- if (l1_size2 && l1_table == NULL) {
>- ret = -ENOMEM;
>- goto fail;
>- }
>- l1_allocated = true;
>-
> ret = bdrv_pread(bs->file, l1_table_offset, l1_table, l1_size2);
> if (ret < 0) {
> goto fail;
>@@ -912,8 +908,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
> be64_to_cpus(&l1_table[i]);
> } else {
> assert(l1_size == s->l1_size);
>- l1_table = s->l1_table;
>- l1_allocated = false;
>+ memcpy(l1_table, s->l1_table, l1_size2);
> }
>
> for(i = 0; i < l1_size; i++) {
>@@ -1055,13 +1050,11 @@ fail:
> }
>
> ret = bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table, l1_size2);
>-
>- for (i = 0; i < l1_size; i++) {
>- be64_to_cpus(&l1_table[i]);
>+ if (ret == 0) {
>+ memcpy(s->l1_table, l1_table, l1_size2);
I made a mistake, big-endian l1 table was copied back to s->l1_table.
> }
> }
>- if (l1_allocated)
>- g_free(l1_table);
>+ g_free(l1_table);
> return ret;
> }
>
>--
>1.7.12.4