NFSD: Count bytes instead of pages in the NFSv3 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/nfs3proc.c

@@ -462,10 +462,7 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
 {
 	struct nfsd3_readdirargs *argp = rqstp->rq_argp;
 	struct nfsd3_readdirres  *resp = rqstp->rq_resp;
-	int		count = 0;
 	loff_t		offset;
-	struct page	**p;
-	caddr_t		page_addr = NULL;
 
 	dprintk("nfsd: READDIR(3)  %s %d bytes at %d\n",
 				SVCFH_fmt(&argp->fh),
@@ -476,6 +473,7 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
 	/* Read directory and encode entries on the fly */
 	fh_copy(&resp->fh, &argp->fh);
 
+	resp->count = 0;
 	resp->common.err = nfs_ok;
 	resp->rqstp = rqstp;
 	offset = argp->cookie;
@@ -483,18 +481,6 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
 	resp->status = nfsd_readdir(rqstp, &resp->fh, &offset,
 				    &resp->common, nfs3svc_encode_entry);
 	memcpy(resp->verf, argp->verf, 8);
-	count = 0;
-	for (p = rqstp->rq_respages + 1; p < rqstp->rq_next_page; p++) {
-		page_addr = page_address(*p);
-
-		if (((caddr_t)resp->buffer >= page_addr) &&
-		    ((caddr_t)resp->buffer < page_addr + PAGE_SIZE)) {
-			count += (caddr_t)resp->buffer - page_addr;
-			break;
-		}
-		count += PAGE_SIZE;
-	}
-	resp->count = count >> 2;
 	nfs3svc_encode_cookie3(resp, offset);
 
 	return rpc_success;
@@ -509,10 +495,7 @@ nfsd3_proc_readdirplus(struct svc_rqst *rqstp)
 {
 	struct nfsd3_readdirargs *argp = rqstp->rq_argp;
 	struct nfsd3_readdirres  *resp = rqstp->rq_resp;
-	int	count = 0;
 	loff_t	offset;
-	struct page **p;
-	caddr_t	page_addr = NULL;
 
 	dprintk("nfsd: READDIR+(3) %s %d bytes at %d\n",
 				SVCFH_fmt(&argp->fh),
@@ -523,6 +506,7 @@ nfsd3_proc_readdirplus(struct svc_rqst *rqstp)
 	/* Read directory and encode entries on the fly */
 	fh_copy(&resp->fh, &argp->fh);
 
+	resp->count = 0;
 	resp->common.err = nfs_ok;
 	resp->rqstp = rqstp;
 	offset = argp->cookie;
@@ -539,17 +523,6 @@ nfsd3_proc_readdirplus(struct svc_rqst *rqstp)
 	resp->status = nfsd_readdir(rqstp, &resp->fh, &offset,
 				    &resp->common, nfs3svc_encode_entry_plus);
 	memcpy(resp->verf, argp->verf, 8);
-	for (p = rqstp->rq_respages + 1; p < rqstp->rq_next_page; p++) {
-		page_addr = page_address(*p);
-
-		if (((caddr_t)resp->buffer >= page_addr) &&
-		    ((caddr_t)resp->buffer < page_addr + PAGE_SIZE)) {
-			count += (caddr_t)resp->buffer - page_addr;
-			break;
-		}
-		count += PAGE_SIZE;
-	}
-	resp->count = count >> 2;
 	nfs3svc_encode_cookie3(resp, offset);
 
 out:

fs/nfsd/nfs3xdr.c

@@ -1364,6 +1364,7 @@ encode_entry(struct readdir_cd *ccd, const char *name, int namlen,
 		return -EINVAL;
 	}
 
+	cd->count += num_entry_words;
 	cd->buflen -= num_entry_words;
 	cd->buffer = p;
 	cd->common.err = nfs_ok;