[sheepdog] [PATCH v2 1/2] sheepdog: fix vdi object update after live snapshot
Liu Yuan
namei.unix at gmail.com
Wed Jun 4 08:24:05 CEST 2014
On Tue, Jun 03, 2014 at 11:58:21PM +0900, Hitoshi Mitake wrote:
> 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) {
Seems it is not very obvious and to be honest I still don't get the catch why it
is buggy. Could you please describe it in the commit log why this line is
problematic and we have to use ->create to fix it.
Thanks
Yuan
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