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authorKevin Wolf <kwolf@redhat.com>2012-03-20 15:12:58 +0100
committerKevin Wolf <kwolf@redhat.com>2012-04-20 15:57:30 +0200
commit621f058940ea9f1ef3d8774ef3203544f1228df1 (patch)
treebb1d8a76f9d7d737502e6daf68c143420454e3bc /block.c
parentab3a32ad5ea841c313e5f9c5f0d4ec02a8e9ddfc (diff)
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qcow2: Zero write support
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block.c')
-rw-r--r--block.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/block.c b/block.c
index 421cd1b..fe74ddd 100644
--- a/block.c
+++ b/block.c
@@ -80,6 +80,8 @@ static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
void *opaque,
bool is_write);
static void coroutine_fn bdrv_co_do_rw(void *opaque);
+static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors);
static bool bdrv_exceed_bps_limits(BlockDriverState *bs, int nb_sectors,
bool is_write, double elapsed_time, uint64_t *wait);
@@ -1708,8 +1710,8 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs,
if (drv->bdrv_co_write_zeroes &&
buffer_is_zero(bounce_buffer, iov.iov_len)) {
- ret = drv->bdrv_co_write_zeroes(bs, cluster_sector_num,
- cluster_nb_sectors);
+ ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num,
+ cluster_nb_sectors);
} else {
ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors,
&bounce_qiov);
@@ -1819,9 +1821,15 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
struct iovec iov;
int ret;
+ /* TODO Emulate only part of misaligned requests instead of letting block
+ * drivers return -ENOTSUP and emulate everything */
+
/* First try the efficient write zeroes operation */
if (drv->bdrv_co_write_zeroes) {
- return drv->bdrv_co_write_zeroes(bs, sector_num, nb_sectors);
+ ret = drv->bdrv_co_write_zeroes(bs, sector_num, nb_sectors);
+ if (ret != -ENOTSUP) {
+ return ret;
+ }
}
/* Fall back to bounce buffer if write zeroes is unsupported */