nfsd4: allow exotic read compounds

I'm not sure why a client would want to stuff multiple reads in a
single compound rpc, but it's legal for them to do it, and we should
really support it.

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

diff --git a/Documentation/filesystems/nfs/nfs41-server.txt b/Documentation/filesystems/nfs/nfs41-server.txt
index b930ad0..c49cd7e 100644 (file)
--- a/Documentation/filesystems/nfs/nfs41-server.txt
+++ b/Documentation/filesystems/nfs/nfs41-server.txt
@@ -176,7 +176,5 @@ Nonstandard compound limitations:
   ca_maxrequestsize request and a ca_maxresponsesize reply, so we may
   fail to live up to the promise we made in CREATE_SESSION fore channel
   negotiation.
-* No more than one read-like operation allowed per compound; encoding
-  replies that cross page boundaries (except for read data) not handled.
 
 See also http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues.

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 92f071b..480f12c 100644 (file)
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3139,28 +3139,34 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
        struct xdr_stream *xdr = &resp->xdr;
        u32 eof;
        int v;
-       struct page *page;
        int starting_len = xdr->buf->len - 8;
-       int space_left;
        long len;
+       int thislen;
        __be32 nfserr;
        __be32 tmp;
        __be32 *p;
+       u32 zzz = 0;
+       int pad;
 
        len = maxcount;
        v = 0;
-       while (len) {
-               int thislen;
 
-               page = *(resp->rqstp->rq_next_page);
-               if (!page) { /* ran out of pages */
-                       maxcount -= len;
-                       break;
-               }
+       thislen = (void *)xdr->end - (void *)xdr->p;
+       if (len < thislen)
+               thislen = len;
+       p = xdr_reserve_space(xdr, (thislen+3)&~3);
+       WARN_ON_ONCE(!p);
+       resp->rqstp->rq_vec[v].iov_base = p;
+       resp->rqstp->rq_vec[v].iov_len = thislen;
+       v++;
+       len -= thislen;
+
+       while (len) {
                thislen = min_t(long, len, PAGE_SIZE);
-               resp->rqstp->rq_vec[v].iov_base = page_address(page);
+               p = xdr_reserve_space(xdr, (thislen+3)&~3);
+               WARN_ON_ONCE(!p);
+               resp->rqstp->rq_vec[v].iov_base = p;
                resp->rqstp->rq_vec[v].iov_len = thislen;
-               resp->rqstp->rq_next_page++;
                v++;
                len -= thislen;
        }
@@ -3170,6 +3176,7 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
                        read->rd_vlen, &maxcount);
        if (nfserr)
                return nfserr;
+       xdr_truncate_encode(xdr, starting_len + 8 + ((maxcount+3)&~3));
 
        eof = (read->rd_offset + maxcount >=
               read->rd_fhp->fh_dentry->d_inode->i_size);
@@ -3179,27 +3186,9 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
        tmp = htonl(maxcount);
        write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp, 4);
 
-       resp->xdr.buf->page_len = maxcount;
-       xdr->buf->len += maxcount;
-       xdr->page_ptr += v;
-       xdr->iov = xdr->buf->tail;
-
-       /* Use rest of head for padding and remaining ops: */
-       resp->xdr.buf->tail[0].iov_base = xdr->p;
-       resp->xdr.buf->tail[0].iov_len = 0;
-       if (maxcount&3) {
-               p = xdr_reserve_space(xdr, 4);
-               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);
-       }
-
-       space_left = min_t(int, (void *)xdr->end - (void *)xdr->p,
-                               xdr->buf->buflen - xdr->buf->len);
-       xdr->buf->buflen = xdr->buf->len + space_left;
-       xdr->end = (__be32 *)((void *)xdr->end + space_left);
-
+       pad = (maxcount&3) ? 4 - (maxcount&3) : 0;
+       write_bytes_to_xdr_buf(xdr->buf, starting_len + 8 + maxcount,
+                                                               &zzz, pad);
        return 0;
 
 }
@@ -3224,15 +3213,15 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
                WARN_ON_ONCE(resp->rqstp->rq_splice_ok);
                return nfserr_resource;
        }
-
-       if (resp->xdr.buf->page_len) {
-               WARN_ON_ONCE(resp->rqstp->rq_splice_ok);
+       if (resp->xdr.buf->page_len && resp->rqstp->rq_splice_ok) {
+               WARN_ON_ONCE(1);
                return nfserr_resource;
        }
-
        xdr_commit_encode(xdr);
 
        maxcount = svc_max_payload(resp->rqstp);
+       if (maxcount > xdr->buf->buflen - xdr->buf->len)
+               maxcount = xdr->buf->buflen - xdr->buf->len;
        if (maxcount > read->rd_length)
                maxcount = read->rd_length;