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>

1 files changed, 25 insertions, 36 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 92f071b44f75..480f12c4e590 100644
--- 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;