On Wed, Jun 17, 2009 at 06:03:25PM -0400, bfields wrote:
> On Tue, Jun 16, 2009 at 04:19:49AM +0300, Benny Halevy wrote:
> > From: Andy Adamson <andros@xxxxxxxxxx>
> >
> > Change from page based to memory based NFSv4.1 DRC.
> >
> > We need to allocate memory for the session DRC in the CREATE_SESSION operation
> > because of the guarantee to the client that the memory resource is available
> > for caching responses.
> >
> > In preparation to remove struct nfsd4_cache_entry, add static storage to
> > struct nfsd4_slot to hold up to NFSD_SLOT_CACH_SIZE of all encoded operation
> > data past the encoded sequence operation.
> >
> > Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
> > Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> > ---
> > fs/nfsd/nfs4state.c | 9 +++++++++
> > fs/nfsd/nfs4xdr.c | 1 +
> > include/linux/nfsd/state.h | 2 ++
> > include/linux/nfsd/xdr4.h | 1 +
> > 4 files changed, 13 insertions(+), 0 deletions(-)
> >
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index a6a7968..bf40c6b 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -1052,6 +1052,7 @@ nfsd4_copy_pages(struct page **topages, struct page **frompages, short count)
> > void
> > nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
> > {
> > + struct nfsd4_slot *slot = resp->cstate.slot;
> > struct nfsd4_cache_entry *entry = &resp->cstate.slot->sl_cache_entry;
> > struct svc_rqst *rqstp = resp->rqstp;
> > struct nfsd4_compoundargs *args = rqstp->rq_argp;
> > @@ -1076,10 +1077,14 @@ nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
> > if (nfsd4_not_cached(resp)) {
> > entry->ce_resused = 0;
> > entry->ce_rpchdrlen = 0;
> > + slot->sl_datalen = 0;
> > dprintk("%s Just cache SEQUENCE. ce_cachethis %d\n", __func__,
> > resp->cstate.slot->sl_cache_entry.ce_cachethis);
> > return;
> > }
> > + slot->sl_datalen = (char *)resp->p - (char *)resp->cstate.datap;
> > + memcpy(slot->sl_data, resp->cstate.datap, slot->sl_datalen);
>
> A response (e.g. a read) can span multiple pages, even if it's short.
> So this doesn't work.
(So: probably just write a function copy_xdr_to_buf(xdr_buf, n, p) (if
there isn't one already somewhere) that copies the first n bytes out of
an xdr buffer into a given destination buffer p.)
--b.
>
> --b.
>
> > +
> > entry->ce_resused = rqstp->rq_resused;
> > if (entry->ce_resused > NFSD_PAGES_PER_SLOT + 1)
> > entry->ce_resused = NFSD_PAGES_PER_SLOT + 1;
> > @@ -1127,6 +1132,7 @@ __be32
> > nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
> > struct nfsd4_sequence *seq)
> > {
> > + struct nfsd4_slot *slot = resp->cstate.slot;
> > struct nfsd4_cache_entry *entry = &resp->cstate.slot->sl_cache_entry;
> > __be32 status;
> >
> > @@ -1147,6 +1153,9 @@ nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
> > return nfs_ok;
> > }
> >
> > + /* The sequence operation has been encoded, cstate->datap set. */
> > + memcpy(resp->cstate.datap, slot->sl_data, slot->sl_datalen);
> > +
> > if (!nfsd41_copy_replay_data(resp, entry)) {
> > /*
> > * Not enough room to use the replay rpc header, send the
> > diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> > index c4eda89..7ab83cc 100644
> > --- a/fs/nfsd/nfs4xdr.c
> > +++ b/fs/nfsd/nfs4xdr.c
> > @@ -3072,6 +3072,7 @@ nfsd4_encode_sequence(struct nfsd4_compoundres *resp, int nfserr,
> > WRITE32(0);
> >
> > ADJUST_ARGS();
> > + resp->cstate.datap = p; /* DRC cache data pointer */
> > return 0;
> > }
> >
> > diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
> > index 1ebb05e..8d5daf7 100644
> > --- a/include/linux/nfsd/state.h
> > +++ b/include/linux/nfsd/state.h
> > @@ -113,6 +113,8 @@ struct nfsd4_cache_entry {
> > struct nfsd4_slot {
> > bool sl_inuse;
> > u32 sl_seqid;
> > + u32 sl_datalen;
> > + char sl_data[NFSD_SLOT_CACHE_SIZE];
> > struct nfsd4_cache_entry sl_cache_entry;
> > };
> >
> > diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
> > index 5e4beb0..5144c92 100644
> > --- a/include/linux/nfsd/xdr4.h
> > +++ b/include/linux/nfsd/xdr4.h
> > @@ -52,6 +52,7 @@ struct nfsd4_compound_state {
> > struct nfsd4_session *session;
> > struct nfsd4_slot *slot;
> > __be32 *statp;
> > + __be32 *datap;
> > size_t iovlen;
> > u32 minorversion;
> > u32 status;
> > --
> > 1.6.3
> >
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