[sheepdog] [PATCH v2 1/2] sheepdog: fix vdi object update after live snapshot

Hitoshi Mitake mitake.hitoshi at gmail.com
Tue Jun 3 16:58:21 CEST 2014


On Tue, Jun 3, 2014 at 9:41 PM, Liu Yuan <namei.unix at gmail.com> wrote:
> On Tue, Jun 03, 2014 at 01:54:21PM +0900, Hitoshi Mitake wrote:
>> sheepdog driver should decide a write request is COW or not based on
>> inode object which is active when the write request is issued.
>>
>> Cc: Kevin Wolf <kwolf at redhat.com>
>> Cc: Stefan Hajnoczi <stefanha at redhat.com>
>> Cc: Liu Yuan <namei.unix at gmail.com>
>> Cc: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
>> Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
>> ---
>>  block/sheepdog.c |   40 +++++++++++++++++++++++-----------------
>>  1 files changed, 23 insertions(+), 17 deletions(-)
>>
>> diff --git a/block/sheepdog.c b/block/sheepdog.c
>> index 4ecbf5f..637e57f 100644
>> --- a/block/sheepdog.c
>> +++ b/block/sheepdog.c
>> @@ -282,6 +282,7 @@ typedef struct AIOReq {
>>      unsigned int data_len;
>>      uint8_t flags;
>>      uint32_t id;
>> +    bool create;
>>
>>      QLIST_ENTRY(AIOReq) aio_siblings;
>>  } AIOReq;
>> @@ -404,7 +405,7 @@ static const char * sd_strerror(int err)
>>
>>  static inline AIOReq *alloc_aio_req(BDRVSheepdogState *s, SheepdogAIOCB *acb,
>>                                      uint64_t oid, unsigned int data_len,
>> -                                    uint64_t offset, uint8_t flags,
>> +                                    uint64_t offset, uint8_t flags, bool create,
>>                                      uint64_t base_oid, unsigned int iov_offset)
>>  {
>>      AIOReq *aio_req;
>> @@ -418,6 +419,7 @@ static inline AIOReq *alloc_aio_req(BDRVSheepdogState *s, SheepdogAIOCB *acb,
>>      aio_req->data_len = data_len;
>>      aio_req->flags = flags;
>>      aio_req->id = s->aioreq_seq_num++;
>> +    aio_req->create = create;
>>
>>      acb->nr_pending++;
>>      return aio_req;
>> @@ -664,8 +666,8 @@ static int do_req(int sockfd, SheepdogReq *hdr, void *data,
>>  }
>>
>>  static void coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
>> -                           struct iovec *iov, int niov, bool create,
>> -                           enum AIOCBState aiocb_type);
>> +                                         struct iovec *iov, int niov,
>> +                                         enum AIOCBState aiocb_type);
>>  static void coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req);
>>  static int reload_inode(BDRVSheepdogState *s, uint32_t snapid, const char *tag);
>>  static int get_sheep_fd(BDRVSheepdogState *s, Error **errp);
>> @@ -698,7 +700,7 @@ static void coroutine_fn send_pending_req(BDRVSheepdogState *s, uint64_t oid)
>>          /* move aio_req from pending list to inflight one */
>>          QLIST_REMOVE(aio_req, aio_siblings);
>>          QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
>> -        add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov, false,
>> +        add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
>>                          acb->aiocb_type);
>>      }
>>  }
>> @@ -797,7 +799,7 @@ static void coroutine_fn aio_read_response(void *opaque)
>>          }
>>          idx = data_oid_to_idx(aio_req->oid);
>>
>> -        if (s->inode.data_vdi_id[idx] != s->inode.vdi_id) {
>> +        if (aio_req->create) {
>>              /*
>>               * If the object is newly created one, we need to update
>>               * the vdi object (metadata object).  min_dirty_data_idx
>> @@ -1117,8 +1119,8 @@ out:
>>  }
>>
>>  static void coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
>> -                           struct iovec *iov, int niov, bool create,
>> -                           enum AIOCBState aiocb_type)
>> +                                         struct iovec *iov, int niov,
>> +                                         enum AIOCBState aiocb_type)
>>  {
>>      int nr_copies = s->inode.nr_copies;
>>      SheepdogObjReq hdr;
>> @@ -1129,6 +1131,7 @@ static void coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
>>      uint64_t offset = aio_req->offset;
>>      uint8_t flags = aio_req->flags;
>>      uint64_t old_oid = aio_req->base_oid;
>> +    bool create = aio_req->create;
>>
>>      if (!nr_copies) {
>>          error_report("bug");
>> @@ -1315,6 +1318,7 @@ static bool check_simultaneous_create(BDRVSheepdogState *s, AIOReq *aio_req)
>>              DPRINTF("simultaneous create to %" PRIx64 "\n", aio_req->oid);
>>              aio_req->flags = 0;
>>              aio_req->base_oid = 0;
>> +            aio_req->create = false;
>>              QLIST_REMOVE(aio_req, aio_siblings);
>>              QLIST_INSERT_HEAD(&s->pending_aio_head, aio_req, aio_siblings);
>>              return true;
>> @@ -1327,7 +1331,8 @@ static bool check_simultaneous_create(BDRVSheepdogState *s, AIOReq *aio_req)
>>  static void coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req)
>>  {
>>      SheepdogAIOCB *acb = aio_req->aiocb;
>> -    bool create = false;
>> +
>> +    aio_req->create = false;
>>
>>      /* check whether this request becomes a CoW one */
>>      if (acb->aiocb_type == AIOCB_WRITE_UDATA && is_data_obj(aio_req->oid)) {
>> @@ -1345,17 +1350,17 @@ static void coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req)
>>              aio_req->base_oid = vid_to_data_oid(s->inode.data_vdi_id[idx], idx);
>>              aio_req->flags |= SD_FLAG_CMD_COW;
>>          }
>> -        create = true;
>> +        aio_req->create = true;
>>      }
>>  out:
>>      if (is_data_obj(aio_req->oid)) {
>> -        add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov, create,
>> +        add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
>>                          acb->aiocb_type);
>>      } else {
>>          struct iovec iov;
>>          iov.iov_base = &s->inode;
>>          iov.iov_len = sizeof(s->inode);
>> -        add_aio_request(s, aio_req, &iov, 1, false, AIOCB_WRITE_UDATA);
>> +        add_aio_request(s, aio_req, &iov, 1, AIOCB_WRITE_UDATA);
>>      }
>>  }
>>
>> @@ -1849,9 +1854,9 @@ static void coroutine_fn sd_write_done(SheepdogAIOCB *acb)
>>          iov.iov_base = &s->inode;
>>          iov.iov_len = sizeof(s->inode);
>>          aio_req = alloc_aio_req(s, acb, vid_to_vdi_oid(s->inode.vdi_id),
>> -                                data_len, offset, 0, 0, offset);
>> +                                data_len, offset, 0, false, 0, offset);
>>          QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
>> -        add_aio_request(s, aio_req, &iov, 1, false, AIOCB_WRITE_UDATA);
>> +        add_aio_request(s, aio_req, &iov, 1, AIOCB_WRITE_UDATA);
>>
>>          acb->aio_done_func = sd_finish_aiocb;
>>          acb->aiocb_type = AIOCB_WRITE_UDATA;
>> @@ -2049,7 +2054,8 @@ static int coroutine_fn sd_co_rw_vector(void *p)
>>              DPRINTF("new oid %" PRIx64 "\n", oid);
>>          }
>>
>> -        aio_req = alloc_aio_req(s, acb, oid, len, offset, flags, old_oid, done);
>> +        aio_req = alloc_aio_req(s, acb, oid, len, offset, flags, create,
>> +                                old_oid, done);
>>          QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
>>
>>          if (create) {
>> @@ -2058,7 +2064,7 @@ static int coroutine_fn sd_co_rw_vector(void *p)
>>              }
>>          }
>>
>> -        add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov, create,
>> +        add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
>>                          acb->aiocb_type);
>>      done:
>>          offset = 0;
>> @@ -2138,9 +2144,9 @@ static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
>>      acb->aio_done_func = sd_finish_aiocb;
>>
>>      aio_req = alloc_aio_req(s, acb, vid_to_vdi_oid(s->inode.vdi_id),
>> -                            0, 0, 0, 0, 0);
>> +                            0, 0, 0, false, 0, 0);
>>      QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
>> -    add_aio_request(s, aio_req, NULL, 0, false, acb->aiocb_type);
>> +    add_aio_request(s, aio_req, NULL, 0, acb->aiocb_type);
>>
>>      qemu_coroutine_yield();
>>      return acb->ret;
>> --
>> 1.7.1
>>
>
> Which line is the problem and which line fixes it? Seems not easy to find it out.
> I just saw some restructuring of 'create' field.
>

The below line in aio_read_response() is the problem:

> @@ -797,7 +799,7 @@ static void coroutine_fn aio_read_response(void *opaque)
>          }
>          idx = data_oid_to_idx(aio_req->oid);
>
> -        if (s->inode.data_vdi_id[idx] != s->inode.vdi_id) {

Thanks,
Hitoshi



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