nfsd4: separate splice and readv cases

The splice and readv cases are actually quite different--for example the
former case ignores the array of vectors we build up for the latter.

It is probably clearer to separate the two cases entirely.

There's some code duplication between the split out encoders, but this
is only temporary and will be fixed by a later patch.

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

1 files changed, 131 insertions, 42 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index f6a5cb722697..bad762b6cf10 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3069,41 +3069,84 @@ nfsd4_encode_open_downgrade(struct nfsd4_compoundres *resp, __be32 nfserr, struc
 	return nfserr;
 }
 
-static __be32
-nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
-		  struct nfsd4_read *read)
+static __be32 nfsd4_encode_splice_read(
+				struct nfsd4_compoundres *resp,
+				struct nfsd4_read *read,
+				struct file *file, unsigned long maxcount)
 {
-	u32 eof;
-	int v;
-	struct page *page;
-	unsigned long maxcount; 
 	struct xdr_stream *xdr = &resp->xdr;
-	int starting_len = xdr->buf->len;
+	u32 eof;
+	int starting_len = xdr->buf->len - 8;
 	int space_left;
-	long len;
+	__be32 nfserr;
+	__be32 tmp;
 	__be32 *p;
 
-	if (nfserr)
-		return nfserr;
-
-	p = xdr_reserve_space(xdr, 8); /* eof flag and byte count */
-	if (!p) {
-		WARN_ON_ONCE(resp->rqstp->rq_splice_ok);
+	/*
+	 * Don't inline pages unless we know there's room for eof,
+	 * count, and possible padding:
+	 */
+	if (xdr->end - xdr->p < 3)
 		return nfserr_resource;
+
+	nfserr = nfsd_splice_read(read->rd_rqstp, file,
+				  read->rd_offset, &maxcount);
+	if (nfserr) {
+		/*
+		 * nfsd_splice_actor may have already messed with the
+		 * page length; reset it so as not to confuse
+		 * xdr_truncate_encode:
+		 */
+		xdr->buf->page_len = 0;
+		return nfserr;
 	}
 
-	/* Make sure there will be room for padding if needed: */
-	if (xdr->end - xdr->p < 1)
-		return nfserr_resource;
+	eof = (read->rd_offset + maxcount >=
+	       read->rd_fhp->fh_dentry->d_inode->i_size);
 
-	if (resp->xdr.buf->page_len) {
-		WARN_ON_ONCE(resp->rqstp->rq_splice_ok);
-		return nfserr_resource;
+	tmp = htonl(eof);
+	write_bytes_to_xdr_buf(xdr->buf, starting_len    , &tmp, 4);
+	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 += (maxcount + PAGE_SIZE - 1) / PAGE_SIZE;
+	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);
 	}
 
-	maxcount = svc_max_payload(resp->rqstp);
-	if (maxcount > read->rd_length)
-		maxcount = read->rd_length;
+	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);
+
+	return 0;
+}
+
+static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
+				 struct nfsd4_read *read,
+				 struct file *file, unsigned long maxcount)
+{
+	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;
+	__be32 nfserr;
+	__be32 tmp;
+	__be32 *p;
 
 	len = maxcount;
 	v = 0;
@@ -3124,34 +3167,26 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
 	}
 	read->rd_vlen = v;
 
-	nfserr = nfsd_read_file(read->rd_rqstp, read->rd_fhp, read->rd_filp,
-			read->rd_offset, resp->rqstp->rq_vec, read->rd_vlen,
-			&maxcount);
-
-	if (nfserr) {
-		/*
-		 * nfsd_splice_actor may have already messed with the
-		 * page length; reset it so as not to confuse
-		 * xdr_truncate_encode:
-		 */
-		xdr->buf->page_len = 0;
-		xdr_truncate_encode(xdr, starting_len);
+	nfserr = nfsd_readv(file, read->rd_offset, resp->rqstp->rq_vec,
+			read->rd_vlen, &maxcount);
+	if (nfserr)
 		return nfserr;
-	}
+
 	eof = (read->rd_offset + maxcount >=
 	       read->rd_fhp->fh_dentry->d_inode->i_size);
 
-	WRITE32(eof);
-	WRITE32(maxcount);
-	WARN_ON_ONCE(resp->xdr.buf->head[0].iov_len != (char *)p
-				- (char *)resp->xdr.buf->head[0].iov_base);
+	tmp = htonl(eof);
+	write_bytes_to_xdr_buf(xdr->buf, starting_len    , &tmp, 4);
+	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 = p;
+	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);
@@ -3167,6 +3202,60 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
 	xdr->end = (__be32 *)((void *)xdr->end + space_left);
 
 	return 0;
+
+}
+
+static __be32
+nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
+		  struct nfsd4_read *read)
+{
+	unsigned long maxcount;
+	struct xdr_stream *xdr = &resp->xdr;
+	struct file *file = read->rd_filp;
+	int starting_len = xdr->buf->len;
+	struct raparms *ra;
+	__be32 *p;
+	__be32 err;
+
+	if (nfserr)
+		return nfserr;
+
+	p = xdr_reserve_space(xdr, 8); /* eof flag and byte count */
+	if (!p) {
+		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);
+		return nfserr_resource;
+	}
+
+	xdr_commit_encode(xdr);
+
+	maxcount = svc_max_payload(resp->rqstp);
+	if (maxcount > read->rd_length)
+		maxcount = read->rd_length;
+
+	if (!read->rd_filp) {
+		err = nfsd_get_tmp_read_open(resp->rqstp, read->rd_fhp,
+						&file, &ra);
+		if (err)
+			goto err_truncate;
+	}
+
+	if (file->f_op->splice_read && resp->rqstp->rq_splice_ok)
+		err = nfsd4_encode_splice_read(resp, read, file, maxcount);
+	else
+		err = nfsd4_encode_readv(resp, read, file, maxcount);
+
+	if (!read->rd_filp)
+		nfsd_put_tmp_read_open(file, ra);
+
+err_truncate:
+	if (err)
+		xdr_truncate_encode(xdr, starting_len);
+	return err;
 }
 
 static __be32