nfsd4: keep xdr buf length updated

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

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 109b5a8..ef3952a 100644 (file)
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1262,6 +1262,8 @@ static void svcxdr_init_encode(struct svc_rqst *rqstp,
        xdr->iov = head;
        xdr->p   = head->iov_base + head->iov_len;
        xdr->end = head->iov_base + PAGE_SIZE - 2 * RPC_MAX_AUTH_SIZE;
+       /* Tail and page_len should be zero at this point: */
+       buf->len = buf->head[0].iov_len;
 }
 
 /*

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 79b8e1e..57f6081 100644 (file)
--- 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);