NFSD: Hoist rq_vec preparation into nfsd_read() [step two]

Now that the preparation of an rq_vec has been removed from the
generic read path, nfsd_splice_read() no longer needs to reset
rq_next_page.

nfsd4_encode_read() calls nfsd_splice_read() directly. As far as I
can ascertain, resetting rq_next_page for NFSv4 splice reads is
unnecessary because rq_next_page is already set correctly.

Moreover, resetting it might even be incorrect if previous
operations in the COMPOUND have already consumed at least a page of
the send buffer. I would expect that the result would be encoding
the READ payload over previously-encoded results.

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

2 files changed, 17 insertions, 6 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 3887da048232..c67bc904c7b7 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -4103,13 +4103,13 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
 	__be32 zero = xdr_zero;
 	__be32 nfserr;
 
-	read->rd_vlen = xdr_reserve_space_vec(xdr, resp->rqstp->rq_vec, maxcount);
-	if (read->rd_vlen < 0)
+	if (xdr_reserve_space_vec(xdr, maxcount) < 0)
 		return nfserr_resource;
 
-	nfserr = nfsd_readv(resp->rqstp, read->rd_fhp, file, read->rd_offset,
-			    resp->rqstp->rq_vec, read->rd_vlen, &maxcount,
-			    &read->rd_eof);
+	nfserr = nfsd_iter_read(resp->rqstp, read->rd_fhp, file,
+				read->rd_offset, &maxcount,
+				xdr->buf->page_len & ~PAGE_MASK,
+				&read->rd_eof);
 	read->rd_length = maxcount;
 	if (nfserr)
 		return nfserr;
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index d9055b5c496b..37febe1ff039 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1003,6 +1003,18 @@ static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	}
 }
 
+/**
+ * nfsd_splice_read - Perform a VFS read using a splice pipe
+ * @rqstp: RPC transaction context
+ * @fhp: file handle of file to be read
+ * @file: opened struct file of file to be read
+ * @offset: starting byte offset
+ * @count: IN: requested number of bytes; OUT: number of bytes read
+ * @eof: OUT: set non-zero if operation reached the end of the file
+ *
+ * Returns nfs_ok on success, otherwise an nfserr stat value is
+ * returned.
+ */
 __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
 			struct file *file, loff_t offset, unsigned long *count,
 			u32 *eof)
@@ -1016,7 +1028,6 @@ __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	ssize_t host_err;
 
 	trace_nfsd_read_splice(rqstp, fhp, offset, *count);
-	rqstp->rq_next_page = rqstp->rq_respages + 1;
 	host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
 	return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
 }