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.
--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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