Re: [Qemu-devel] [RFC v5] RBD: Add support readv,writev for rbd

[Jaze Lee]

2017-02-16 22:14 GMT+08:00 Jason Dillaman <address@hidden>:
> On Thu, Feb 16, 2017 at 4:00 AM,  <address@hidden> wrote:
>> From: tianqing <address@hidden>
>>
>> Rbd can do readv and writev directly, so wo do not need to transform
>> iov to buf or vice versa any more.
>>
>> Signed-off-by: tianqing <address@hidden>
>> ---
>>  block/rbd.c | 49 ++++++++++++++++++++++++++++++++++++++++++-------
>>  1 file changed, 42 insertions(+), 7 deletions(-)
>>
>> diff --git a/block/rbd.c b/block/rbd.c
>> index a57b3e3..75ae1d6 100644
>> --- a/block/rbd.c
>> +++ b/block/rbd.c
>> @@ -47,7 +47,7 @@
>>   */
>>
>>  /* rbd_aio_discard added in 0.1.2 */
>> -#if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(0, 1, 2)
>> +#if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(12, 0, 0)
>>  #define LIBRBD_SUPPORTS_DISCARD
>>  #else
>>  #undef LIBRBD_SUPPORTS_DISCARD
>
> Do not change this -- discard support is available in very old
> versions of librbd not just the future Luminous release.

Ok. Thanks a lot.



>
>> @@ -73,7 +73,12 @@ typedef struct RBDAIOCB {
>>      BlockAIOCB common;
>>      int64_t ret;
>>      QEMUIOVector *qiov;
>> +/* Note:
>> + * The LIBRBD_SUPPORTS_IOVEC is defined in librbd.h.
>> + */
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>>      char *bounce;
>> +#endif
>>      RBDAIOCmd cmd;
>>      int error;
>>      struct BDRVRBDState *s;
>> @@ -83,7 +88,9 @@ typedef struct RADOSCB {
>>      RBDAIOCB *acb;
>>      struct BDRVRBDState *s;
>>      int64_t size;
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>>      char *buf;
>> +#endif
>>      int64_t ret;
>>  } RADOSCB;
>>
>> @@ -426,11 +433,21 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb)
>>          }
>>      } else {
>>          if (r < 0) {
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>>              memset(rcb->buf, 0, rcb->size);
>> +#else
>> +            iov_memset(acb->qiov->iov, acb->qiov->niov, 0, 0, 
>> acb->qiov->size);
>> +#endif
>>              acb->ret = r;
>>              acb->error = 1;
>>          } else if (r < rcb->size) {
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>>              memset(rcb->buf + r, 0, rcb->size - r);
>> +#else
>> +            iov_memset(acb->qiov->iov, acb->qiov->niov,
>> +                       r, 0, acb->qiov->size - r);
>> +#endif
>> +
>>              if (!acb->error) {
>>                  acb->ret = rcb->size;
>>              }
>> @@ -441,10 +458,12 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb)
>>
>>      g_free(rcb);
>>
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>>      if (acb->cmd == RBD_AIO_READ) {
>>          qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
>>      }
>>      qemu_vfree(acb->bounce);
>> +#endif
>>      acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
>>
>>      qemu_aio_unref(acb);
>> @@ -655,8 +674,10 @@ static BlockAIOCB *rbd_start_aio(BlockDriverState *bs,
>>      RBDAIOCB *acb;
>>      RADOSCB *rcb = NULL;
>>      rbd_completion_t c;
>> -    char *buf;
>>      int r;
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>> +    char *buf = NULL;
>> +#endif
>>
>>      BDRVRBDState *s = bs->opaque;
>>
>> @@ -664,6 +685,8 @@ static BlockAIOCB *rbd_start_aio(BlockDriverState *bs,
>>      acb->cmd = cmd;
>>      acb->qiov = qiov;
>>      assert(!qiov || qiov->size == size);
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>> +
>>      if (cmd == RBD_AIO_DISCARD || cmd == RBD_AIO_FLUSH) {
>>          acb->bounce = NULL;
>>      } else {
>> @@ -672,19 +695,21 @@ static BlockAIOCB *rbd_start_aio(BlockDriverState *bs,
>>              goto failed;
>>          }
>>      }
>> -    acb->ret = 0;
>> -    acb->error = 0;
>> -    acb->s = s;
>> -
>>      if (cmd == RBD_AIO_WRITE) {
>>          qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size);
>>      }
>> -
>>      buf = acb->bounce;
>> +#endif
>> +    acb->ret = 0;
>> +    acb->error = 0;
>> +    acb->s = s;
>>
>>      rcb = g_new(RADOSCB, 1);
>> +
>>      rcb->acb = acb;
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>>      rcb->buf = buf;
>> +#endif
>>      rcb->s = acb->s;
>>      rcb->size = size;
>>      r = rbd_aio_create_completion(rcb, (rbd_callback_t) rbd_finish_aiocb, 
>> &c);
>> @@ -694,10 +719,18 @@ static BlockAIOCB *rbd_start_aio(BlockDriverState *bs,
>>
>>      switch (cmd) {
>>      case RBD_AIO_WRITE:
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>>          r = rbd_aio_write(s->image, off, size, buf, c);
>> +#else
>> +        r = rbd_aio_writev(s->image, qiov->iov, qiov->niov, off, c);
>> +#endif
>>          break;
>>      case RBD_AIO_READ:
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>>          r = rbd_aio_read(s->image, off, size, buf, c);
>> +#else
>> +        r = rbd_aio_readv(s->image, qiov->iov, qiov->niov, off, c);
>> +#endif
>>          break;
>>      case RBD_AIO_DISCARD:
>>          r = rbd_aio_discard_wrapper(s->image, off, size, c);
>> @@ -719,7 +752,9 @@ failed_completion:
>>      rbd_aio_release(c);
>>  failed:
>>      g_free(rcb);
>> +#ifndef LIBRBD_SUPPORTS_IOVEC
>>      qemu_vfree(acb->bounce);
>> +#endif
>>      qemu_aio_unref(acb);
>>      return NULL;
>>  }
>> --
>> 2.10.2
>>
>
>
>
> --
> Jason



-- 
谦谦君子