NFSD: Count bytes instead of pages in the NFSv2 READDIR encoder

Clean up: Counting the bytes used by each returned directory entry
seems less brittle to me than trying to measure consumed pages after
the fact.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfsproc.c

@@ -578,14 +578,12 @@ nfsd_proc_readdir(struct svc_rqst *rqstp)
 	struct nfsd_readdirargs *argp = rqstp->rq_argp;
 	struct nfsd_readdirres *resp = rqstp->rq_resp;
 	loff_t		offset;
-	__be32		*buffer;
 
 	dprintk("nfsd: READDIR  %s %d bytes at %d\n",
 		SVCFH_fmt(&argp->fh),		
 		argp->count, argp->cookie);
 
 	nfsd_init_dirlist_pages(rqstp, resp, argp->count);
-	buffer = resp->buffer;
 
 	resp->offset = NULL;
 	resp->common.err = nfs_ok;
@@ -593,8 +591,6 @@ nfsd_proc_readdir(struct svc_rqst *rqstp)
 	offset = argp->cookie;
 	resp->status = nfsd_readdir(rqstp, &argp->fh, &offset,
 				    &resp->common, nfssvc_encode_entry);
-
-	resp->count = resp->buffer - buffer;
 	nfssvc_encode_nfscookie(resp, offset);
 
 	fh_put(&argp->fh);

fs/nfsd/nfsxdr.c

@@ -584,7 +584,7 @@ nfssvc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
 	p = resp->buffer;
 	*p++ = 0;			/* no more entries */
 	*p++ = htonl((resp->common.err == nfserr_eof));
-	rqstp->rq_res.page_len = (((unsigned long)p-1) & ~PAGE_MASK)+1;
+	rqstp->rq_res.page_len = resp->count << 2;
 
 	return 1;
 }
@@ -667,6 +667,7 @@ nfssvc_encode_entry(void *ccdv, const char *name,
 	cd->offset = p;			/* remember pointer */
 	*p++ = htonl(~0U);		/* offset of next entry */
 
+	cd->count += p - cd->buffer;
 	cd->buflen = buflen;
 	cd->buffer = p;
 	cd->common.err = nfs_ok;