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>

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 3887da0..c67bc90 100644 (file)
--- 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 d9055b5..37febe1 100644 (file)
--- 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);
 }

diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 72014c9..f89ec4b 100644 (file)
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -242,8 +242,7 @@ extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf,
 extern void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
                           struct page **pages, struct rpc_rqst *rqst);
 extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);
-extern int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec,
-               size_t nbytes);
+extern int xdr_reserve_space_vec(struct xdr_stream *xdr, size_t nbytes);
 extern void __xdr_commit_encode(struct xdr_stream *xdr);
 extern void xdr_truncate_encode(struct xdr_stream *xdr, size_t len);
 extern void xdr_truncate_decode(struct xdr_stream *xdr, size_t len);

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 36835b2..2a22e78 100644 (file)
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -1070,22 +1070,22 @@ __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
 }
 EXPORT_SYMBOL_GPL(xdr_reserve_space);
 
-
 /**
  * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
  * @xdr: pointer to xdr_stream
- * @vec: pointer to a kvec array
  * @nbytes: number of bytes to reserve
  *
- * Reserves enough buffer space to encode 'nbytes' of data and stores the
- * pointers in 'vec'. The size argument passed to xdr_reserve_space() is
- * determined based on the number of bytes remaining in the current page to
- * avoid invalidating iov_base pointers when xdr_commit_encode() is called.
+ * The size argument passed to xdr_reserve_space() is determined based
+ * on the number of bytes remaining in the current page to avoid
+ * invalidating iov_base pointers when xdr_commit_encode() is called.
+ *
+ * Return values:
+ *   %0: success
+ *   %-EMSGSIZE: not enough space is available in @xdr
  */
-int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes)
+int xdr_reserve_space_vec(struct xdr_stream *xdr, size_t nbytes)
 {
-       int thislen;
-       int v = 0;
+       size_t thislen;
        __be32 *p;
 
        /*
@@ -1097,21 +1097,19 @@ int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbyte
                xdr->end = xdr->p;
        }
 
+       /* XXX: Let's find a way to make this more efficient */
        while (nbytes) {
                thislen = xdr->buf->page_len % PAGE_SIZE;
                thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
 
                p = xdr_reserve_space(xdr, thislen);
                if (!p)
-                       return -EIO;
+                       return -EMSGSIZE;
 
-               vec[v].iov_base = p;
-               vec[v].iov_len = thislen;
-               v++;
                nbytes -= thislen;
        }
 
-       return v;
+       return 0;
 }
 EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);