nfsd4: convert 4.1 replay encoding

Limits on maxresp_sz mean that we only ever need to replay rpc's that
are contained entirely in the head.

The one exception is very small zero-copy reads.  That's an odd corner
case as clients wouldn't normally ask those to be cached.

in any case, this seems a little more robust.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index b06f9a0..8e22ea4 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1560,6 +1560,7 @@ out_err:
 void
 nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
 {
+       struct xdr_buf *buf = resp->xdr.buf;
        struct nfsd4_slot *slot = resp->cstate.slot;
        unsigned int base;
 
@@ -1573,11 +1574,9 @@ nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
                slot->sl_datalen = 0;
                return;
        }
-       slot->sl_datalen = (char *)resp->xdr.p - (char *)resp->cstate.datap;
-       base = (char *)resp->cstate.datap -
-                                       (char *)resp->xdr.buf->head[0].iov_base;
-       if (read_bytes_from_xdr_buf(resp->xdr.buf, base, slot->sl_data,
-                                   slot->sl_datalen))
+       base = resp->cstate.data_offset;
+       slot->sl_datalen = buf->len - base;
+       if (read_bytes_from_xdr_buf(buf, base, slot->sl_data, slot->sl_datalen))
                WARN("%s: sessions DRC could not cache compound\n", __func__);
        return;
 }
@@ -1618,7 +1617,8 @@ nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
                         struct nfsd4_sequence *seq)
 {
        struct nfsd4_slot *slot = resp->cstate.slot;
-       struct kvec *head = resp->xdr.iov;
+       struct xdr_stream *xdr = &resp->xdr;
+       __be32 *p;
        __be32 status;
 
        dprintk("--> %s slot %p\n", __func__, slot);
@@ -1627,16 +1627,16 @@ nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
        if (status)
                return status;
 
-       /* The sequence operation has been encoded, cstate->datap set. */
-       memcpy(resp->cstate.datap, slot->sl_data, slot->sl_datalen);
+       p = xdr_reserve_space(xdr, slot->sl_datalen);
+       if (!p) {
+               WARN_ON_ONCE(1);
+               return nfserr_serverfault;
+       }
+       xdr_encode_opaque_fixed(p, slot->sl_data, slot->sl_datalen);
+       xdr_commit_encode(xdr);
 
        resp->opcnt = slot->sl_opcnt;
-       resp->xdr.p = resp->cstate.datap + XDR_QUADLEN(slot->sl_datalen);
-       head->iov_len = (void *)resp->xdr.p - head->iov_base;
-       resp->xdr.buf->len = head->iov_len;
-       status = slot->sl_status;
-
-       return status;
+       return slot->sl_status;
 }
 
 /*

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index d3a576d..a90a1e8 100644 (file)
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3659,7 +3659,7 @@ nfsd4_encode_sequence(struct nfsd4_compoundres *resp, __be32 nfserr,
        WRITE32(seq->maxslots - 1); /* sr_target_highest_slotid */
        WRITE32(seq->status_flags);
 
-       resp->cstate.datap = p; /* DRC cache data pointer */
+       resp->cstate.data_offset = xdr->buf->len; /* DRC cache data pointer */
        return 0;
 }
 

diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index ea5ad5d..ee9ffdc 100644 (file)
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -58,7 +58,7 @@ struct nfsd4_compound_state {
        /* For sessions DRC */
        struct nfsd4_session    *session;
        struct nfsd4_slot       *slot;
-       __be32                  *datap;
+       int                     data_offset;
        size_t                  iovlen;
        u32                     minorversion;
        __be32                  status;