On 5/12/2018 4:25 PM, Vladimir Sementsov-Ogievskiy wrote:
> 03.12.2018 13:14, Anton Nefedov wrote:
>> Current write_zeroes implementation is good enough to satisfy this flag too
>>
>> Signed-off-by: Anton Nefedov <anton.nefe...@virtuozzo.com>
>> ---
>> block/file-posix.c | 8 +++++++-
>> 1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/block/file-posix.c b/block/file-posix.c
>> index 07bbdab953..b0b7ab0159 100644
>> --- a/block/file-posix.c
>> +++ b/block/file-posix.c
>> @@ -603,6 +603,7 @@ static int raw_open_common(BlockDriverState *bs, QDict
>> *options,
>> } else {
>> s->discard_zeroes = true;
>> s->has_fallocate = true;
>> + bs->supported_zero_flags = BDRV_REQ_ALLOCATE;
>> }
>> } else {
>> if (!(S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode))) {
>> @@ -646,10 +647,11 @@ static int raw_open_common(BlockDriverState *bs, QDict
>> *options,
>> #ifdef CONFIG_XFS
>> if (platform_test_xfs_fd(s->fd)) {
>> s->is_xfs = true;
>> + bs->supported_zero_flags = BDRV_REQ_ALLOCATE;
>
> why we should handle xfs separately? is there a case with xfs, not handled by
> previous generic if ()?
>
The driver supports ALLOCATE either when it's XFS, or when fallocate is
available. Currently there is no test for fallocate, it's just implied
it's supported until ENOTSUP returned.
I think it's safer (for possible future changes) to set it twice even
though you're right and first condition currently covers the XFS
condition too.
>> }
>> #endif
>>
>> - bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
>> + bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP;
>> ret = 0;
>> fail:
>> if (filename && (bdrv_flags & BDRV_O_TEMPORARY)) {
>> @@ -1520,6 +1522,10 @@ static ssize_t
>> handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
>> }
>> s->has_fallocate = false;
>> }
>> +
>> + if (!s->has_fallocate) {
>> + aiocb->bs->supported_zero_flags &= ~BDRV_REQ_ALLOCATE;
>> + }
>> #endif
>>
>> return -ENOTSUP;
>>
>
>
