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>

3 files changed, 16 insertions, 16 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index b06f9a00ff8d..8e22ea485f99 100644
--- 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 d3a576dbd99b..a90a1e86614a 100644
--- 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 ea5ad5db655b..ee9ffdc8a0cb 100644
--- 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;