On Tue, Dec 30, 2014 at 01:07:11PM +0300, Denis V. Lunev wrote:
> This is preparational commit for tweaks in Parallels image expansion.
> The idea is that enlarge via truncate by one data block is slow. It
> would be much better to use fallocate via bdrv_write_zeroes and
> expand by some significant amount at once.
>
> This patch just adds proper parameters into BDRVParallelsState and
> performs options parsing in parallels_open.
>
> Signed-off-by: Denis V. Lunev <d...@openvz.org>
> CC: Kevin Wolf <kw...@redhat.com>
> CC: Stefan Hajnoczi <stefa...@redhat.com>
> ---
> block/parallels.c | 72
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 72 insertions(+)
>
> diff --git a/block/parallels.c b/block/parallels.c
> index 18b9267..12a9cea 100644
> --- a/block/parallels.c
> +++ b/block/parallels.c
> @@ -30,6 +30,7 @@
> #include "qemu-common.h"
> #include "block/block_int.h"
> #include "qemu/module.h"
> +#include "qapi/util.h"
>
> /**************************************************************/
>
> @@ -54,6 +55,20 @@ typedef struct ParallelsHeader {
> char padding[12];
> } QEMU_PACKED ParallelsHeader;
>
> +
> +typedef enum ParallelsPreallocMode {
> + PRL_PREALLOC_MODE_FALLOCATE = 0,
> + PRL_PREALLOC_MODE_TRUNCATE = 1,
> + PRL_PREALLOC_MODE_MAX = 2,
> +} ParallelsPreallocMode;
> +
> +static const char *prealloc_mode_lookup[] = {
> + "falloc",
> + "truncate",
> + NULL,
There is already generic "preallocaton" option, BLOCK_OPT_PREALLOC,
which is handled by qcow2 and raw-posix. It means slightly different
thing: the *whole* image is preallocated using the method specified.
I think it would make sense to consolidate that option with this new
batched allocation in the generic block code. I guess qcow2 and
raw-posix would benefit from it, too.
At any rate I think it's a matter for a separate patchset.
Roman.
