nfsd4: keep xdr buf length updated

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

1 files changed, 13 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 79b8e1ef0f39..57f60810b745 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3046,6 +3046,7 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
         if (nfserr) {
                 xdr->p -= 2;
                 xdr->iov->iov_len -= 8;
+                xdr->buf->len -= 8;
                 return nfserr;
         }
         eof = (read->rd_offset + maxcount >=
@@ -3053,9 +3054,10 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
 
         WRITE32(eof);
         WRITE32(maxcount);
-        resp->xdr.buf->head[0].iov_len = (char *)p
-                                - (char *)resp->xdr.buf->head[0].iov_base;
+        WARN_ON_ONCE(resp->xdr.buf->head[0].iov_len != (char *)p
+                                - (char *)resp->xdr.buf->head[0].iov_base);
         resp->xdr.buf->page_len = maxcount;
+        xdr->buf->len += maxcount;
         xdr->iov = xdr->buf->tail;
 
         /* Use rest of head for padding and remaining ops: */
@@ -3066,6 +3068,7 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
                 WRITE32(0);
                 resp->xdr.buf->tail[0].iov_base += maxcount&3;
                 resp->xdr.buf->tail[0].iov_len = 4 - (maxcount&3);
+                xdr->buf->len -= (maxcount&3);
         }
         return 0;
 }
@@ -3102,6 +3105,7 @@ nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd
         if (nfserr) {
                 xdr->p--;
                 xdr->iov->iov_len -= 4;
+                xdr->buf->len -= 4;
                 return nfserr;
         }
 
@@ -3109,6 +3113,7 @@ nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd
         resp->xdr.buf->head[0].iov_len = (char *)p
                                 - (char *)resp->xdr.buf->head[0].iov_base;
         resp->xdr.buf->page_len = maxcount;
+        xdr->buf->len += maxcount;
         xdr->iov = xdr->buf->tail;
 
         /* Use rest of head for padding and remaining ops: */
@@ -3189,6 +3194,7 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
         *p++ = htonl(readdir->common.err == nfserr_eof);
         resp->xdr.buf->page_len = ((char *)p) -
                 (char*)page_address(*(resp->rqstp->rq_next_page-1));
+        xdr->buf->len += xdr->buf->page_len;
 
         xdr->iov = xdr->buf->tail;
 
@@ -3204,6 +3210,7 @@ err_no_verf:
         xdr->p = savep;
         xdr->iov->iov_len = ((char *)resp->xdr.p)
                                 - (char *)resp->xdr.buf->head[0].iov_base;
+        xdr->buf->len = xdr->iov->iov_len;
         return nfserr;
 }
 
@@ -3789,6 +3796,10 @@ nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compo
          * All that remains is to write the tag and operation count...
          */
         struct nfsd4_compound_state *cs = &resp->cstate;
+        struct xdr_buf *buf = resp->xdr.buf;
+
+        WARN_ON_ONCE(buf->len != buf->head[0].iov_len + buf->page_len +
+                                 buf->tail[0].iov_len);
 
         p = resp->tagp;
         *p++ = htonl(resp->taglen);