On 06.05.19 14:23, Stefano Garzarella wrote: > This patch adds the support of preallocation (off/full) for the RBD > block driver. > If available, we use rbd_writesame() to quickly fill the image when > full preallocation is required. > > Signed-off-by: Stefano Garzarella <sgarz...@redhat.com> > --- > v2: > - Use 4 KiB buffer for rbd_writesame() [Jason] > - Use "rbd_concurrent_management_ops" and "stripe_unit" to limit > concurrent ops to the backing cluster [Jason] > --- > block/rbd.c | 188 +++++++++++++++++++++++++++++++++++++++---- > qapi/block-core.json | 4 +- > 2 files changed, 175 insertions(+), 17 deletions(-)
This patch conflicts a bit with the rbd file growth patch, so that would
need to be resolved in a v3.
But still, that doesn’t prevent me from reviewing it as it is:
> diff --git a/block/rbd.c b/block/rbd.c
> index 0c549c9935..bc54395e1c 100644
> --- a/block/rbd.c
> +++ b/block/rbd.c
[...]
> @@ -331,6 +333,147 @@ static void qemu_rbd_memset(RADOSCB *rcb, int64_t offs)
[...]
> +static int qemu_rbd_do_truncate(rados_t cluster, rbd_image_t image,
> + int64_t offset, PreallocMode prealloc,
> + Error **errp)
> +{
[...]
> +#ifdef LIBRBD_SUPPORTS_WRITESAME
> + uint64_t stripe_unit, writesame_max_size;
> + int max_concurrent_ops;
> +
> + max_concurrent_ops = qemu_rbd_get_max_concurrent_ops(cluster);
> + ret = rbd_get_stripe_unit(image, &stripe_unit);
> + if (ret < 0) {
> + error_setg_errno(errp, -ret, "Failed to get stripe unit");
> + goto out;
> + }
> +
> + /*
> + * We limit the rbd_writesame() size to avoid to spawn more then
s/then/than/
> + * 'rbd_concurrent_management_ops' concurrent operations.
> + */
> + writesame_max_size = MIN(stripe_unit * max_concurrent_ops, INT_MAX);
> +#endif /* LIBRBD_SUPPORTS_WRITESAME */
> +
> + buf = g_malloc(buf_size);
> + /*
> + * Some versions of rbd_writesame() discards writes of buffers with
> + * all zeroes. In order to avoid this behaviour, we set the first
> byte
> + * to one.
> + */
> + buf[0] = 1;
But I guess you’ll need to rewrite it as zero later, or the
“bdrv_rbd.bdrv_has_zero_init = bdrv_has_zero_init_1” is no longer quite
true.
[...]
> @@ -449,6 +603,16 @@ static int coroutine_fn qemu_rbd_co_create_opts(const
> char *filename,
> BLOCK_OPT_CLUSTER_SIZE,
> 0);
> rbd_opts->has_cluster_size = (rbd_opts->cluster_size != 0);
>
> + prealloc = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
> + rbd_opts->preallocation = qapi_enum_parse(&PreallocMode_lookup, prealloc,
> + PREALLOC_MODE_OFF, &local_err);
You also need to set rbd_opts->has_preallocation to true.
> + g_free(prealloc);
> + if (local_err) {
> + ret = -EINVAL;
> + error_propagate(errp, local_err);
> + goto exit;
> + }
> +
> options = qdict_new();
> qemu_rbd_parse_filename(filename, options, &local_err);
> if (local_err) {
[...]
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 7ccbfff9d0..db25a4065b 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -4277,13 +4277,15 @@
> # point to a snapshot.
> # @size Size of the virtual disk in bytes
> # @cluster-size RBD object size
> +# @preallocation Preallocation mode (allowed values: off, full)
There should be a "(Since: 4.1)" note here.
Max
> #
> # Since: 2.12
> ##
> { 'struct': 'BlockdevCreateOptionsRbd',
> 'data': { 'location': 'BlockdevOptionsRbd',
> 'size': 'size',
> - '*cluster-size' : 'size' } }
> + '*cluster-size' : 'size',
> + '*preallocation': 'PreallocMode' } }
>
> ##
> # @BlockdevVmdkSubformat:
>
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