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[Qemu-devel] [PATCH 6/6] qcow2: merge is_zero_cluster helpers into qcow2
From: |
Denis V. Lunev |
Subject: |
[Qemu-devel] [PATCH 6/6] qcow2: merge is_zero_cluster helpers into qcow2_co_write_zeroes |
Date: |
Sat, 14 May 2016 15:01:13 +0300 |
They are used once only. This makes code more compact.
The patch also improves comments in the code.
Signed-off-by: Denis V. Lunev <address@hidden>
CC: Kevin Wolf <address@hidden>
---
block/qcow2.c | 39 +++++++++++++++------------------------
1 file changed, 15 insertions(+), 24 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 05beb64..feaf146 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2405,27 +2405,6 @@ finish:
}
-static bool is_zero_cluster(BlockDriverState *bs, int64_t start)
-{
- BDRVQcow2State *s = bs->opaque;
- int nr;
- BlockDriverState *file;
- int64_t res = bdrv_get_block_status_above(bs, NULL, start,
- s->cluster_sectors, &nr, &file);
- return res >= 0 && (res & BDRV_BLOCK_ZERO);
-}
-
-static bool is_zero_cluster_top_locked(BlockDriverState *bs, int64_t start)
-{
- BDRVQcow2State *s = bs->opaque;
- int nr = s->cluster_sectors;
- uint64_t off;
- int ret;
-
- ret = qcow2_get_cluster_offset(bs, start << BDRV_SECTOR_BITS, &nr, &off);
- return ret == QCOW2_CLUSTER_UNALLOCATED || ret == QCOW2_CLUSTER_ZERO;
-}
-
static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
{
@@ -2439,20 +2418,32 @@ static coroutine_fn int
qcow2_co_write_zeroes(BlockDriverState *bs,
nb_sectors);
if (head != 0 || tail != 0) {
- int64_t cl_start = sector_num - head;
+ BlockDriverState *file;
+ uint64_t off;
+ int nr;
+
+ int64_t cl_start = sector_num - head, res;
assert(cl_start + s->cluster_sectors >= sector_num + nb_sectors);
sector_num = cl_start;
nb_sectors = s->cluster_sectors;
- if (!is_zero_cluster(bs, sector_num)) {
+ /* check that the cluster is zeroed taking into account entire
+ backing chain */
+ nr = s->cluster_sectors;
+ res = bdrv_get_block_status_above(bs, NULL, cl_start,
+ s->cluster_sectors, &nr, &file);
+ if (res < 0 || !(res & BDRV_BLOCK_ZERO)) {
return -ENOTSUP;
}
qemu_co_mutex_lock(&s->lock);
/* We can have new write after previous check */
- if (!is_zero_cluster_top_locked(bs, sector_num)) {
+ nr = s->cluster_sectors;
+ ret = qcow2_get_cluster_offset(bs, cl_start << BDRV_SECTOR_BITS,
+ &nr, &off);
+ if (ret != QCOW2_CLUSTER_UNALLOCATED && ret != QCOW2_CLUSTER_ZERO) {
qemu_co_mutex_unlock(&s->lock);
return -ENOTSUP;
}
--
2.5.0
- [Qemu-devel] [PATCH 0/6] qcow2_co_write_zeroes and related improvements, Denis V. Lunev, 2016/05/14
- [Qemu-devel] [PATCH 1/6] qemu-io: enable tracing in qemu-io, Denis V. Lunev, 2016/05/14
- [Qemu-devel] [PATCH 2/6] block: split write_zeroes always, Denis V. Lunev, 2016/05/14
- [Qemu-devel] [PATCH 3/6] qcow2: simplify logic in qcow2_co_write_zeroes, Denis V. Lunev, 2016/05/14
- [Qemu-devel] [PATCH 6/6] qcow2: merge is_zero_cluster helpers into qcow2_co_write_zeroes,
Denis V. Lunev <=
- [Qemu-devel] [PATCH 5/6] qcow2: fix condition in is_zero_cluster, Denis V. Lunev, 2016/05/14
- [Qemu-devel] [PATCH 4/6] qcow2: add tracepoints for qcow2_co_write_zeroes, Denis V. Lunev, 2016/05/14