nfsd: Fix NFSv4 READ on RDMA when using readv
commit 412055398b9e67e07347a936fc4a6adddabe9cf4 upstream.
svcrdma expects that the payload falls precisely into the xdr_buf
page vector. This does not seem to be the case for
nfsd4_encode_readv().
This code is called only when fops->splice_read is missing or when
RQ_SPLICE_OK is clear, so it's not a noticeable problem in many
common cases.
Add new transport method: ->xpo_read_payload so that when a READ
payload does not fit exactly in rq_res's page vector, the XDR
encoder can inform the RPC transport exactly where that payload is,
without the payload's XDR pad.
That way, when a Write chunk is present, the transport knows what
byte range in the Reply message is supposed to be matched with the
chunk.
Note that the Linux NFS server implementation of NFS/RDMA can
currently handle only one Write chunk per RPC-over-RDMA message.
This simplifies the implementation of this fix.
Fixes: b04209806384 ("nfsd4: allow exotic read compounds")
Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=198053
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Timo Rothenpieler <timo@rothenpieler.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 533d0fc..d6f2445 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3530,17 +3530,17 @@
u32 zzz = 0;
int pad;
+ /*
+ * svcrdma requires every READ payload to start somewhere
+ * in xdr->pages.
+ */
+ if (xdr->iov == xdr->buf->head) {
+ xdr->iov = NULL;
+ xdr->end = xdr->p;
+ }
+
len = maxcount;
v = 0;
-
- thislen = min_t(long, len, ((void *)xdr->end - (void *)xdr->p));
- p = xdr_reserve_space(xdr, (thislen+3)&~3);
- WARN_ON_ONCE(!p);
- resp->rqstp->rq_vec[v].iov_base = p;
- resp->rqstp->rq_vec[v].iov_len = thislen;
- v++;
- len -= thislen;
-
while (len) {
thislen = min_t(long, len, PAGE_SIZE);
p = xdr_reserve_space(xdr, (thislen+3)&~3);
@@ -3559,6 +3559,8 @@
read->rd_length = maxcount;
if (nfserr)
return nfserr;
+ if (svc_encode_read_payload(resp->rqstp, starting_len + 8, maxcount))
+ return nfserr_io;
xdr_truncate_encode(xdr, starting_len + 8 + ((maxcount+3)&~3));
tmp = htonl(eof);
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 1afe38e..82665ff 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -517,6 +517,9 @@
void svc_reserve(struct svc_rqst *rqstp, int space);
struct svc_pool * svc_pool_for_cpu(struct svc_serv *serv, int cpu);
char * svc_print_addr(struct svc_rqst *, char *, size_t);
+int svc_encode_read_payload(struct svc_rqst *rqstp,
+ unsigned int offset,
+ unsigned int length);
unsigned int svc_fill_write_vector(struct svc_rqst *rqstp,
struct page **pages,
struct kvec *first, size_t total);
diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index fddad9f..26f282e 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -137,6 +137,8 @@
unsigned int rc_page_count;
unsigned int rc_hdr_count;
u32 rc_inv_rkey;
+ unsigned int rc_read_payload_offset;
+ unsigned int rc_read_payload_length;
struct page *rc_pages[RPCSVC_MAXPAGES];
};
@@ -171,7 +173,9 @@
struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *head, __be32 *p);
extern int svc_rdma_send_write_chunk(struct svcxprt_rdma *rdma,
- __be32 *wr_ch, struct xdr_buf *xdr);
+ __be32 *wr_ch, struct xdr_buf *xdr,
+ unsigned int offset,
+ unsigned long length);
extern int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma,
__be32 *rp_ch, bool writelist,
struct xdr_buf *xdr);
@@ -190,6 +194,8 @@
struct svc_rdma_send_ctxt *ctxt,
struct xdr_buf *xdr, __be32 *wr_lst);
extern int svc_rdma_sendto(struct svc_rqst *);
+extern int svc_rdma_read_payload(struct svc_rqst *rqstp, unsigned int offset,
+ unsigned int length);
/* svc_rdma_transport.c */
extern int svc_rdma_create_listen(struct svc_serv *, int, struct sockaddr *);
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index ea6f46b..9e1e046 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -21,6 +21,8 @@
int (*xpo_has_wspace)(struct svc_xprt *);
int (*xpo_recvfrom)(struct svc_rqst *);
int (*xpo_sendto)(struct svc_rqst *);
+ int (*xpo_read_payload)(struct svc_rqst *, unsigned int,
+ unsigned int);
void (*xpo_release_rqst)(struct svc_rqst *);
void (*xpo_detach)(struct svc_xprt *);
void (*xpo_free)(struct svc_xprt *);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index d11b705..f0dcb6d 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1635,6 +1635,22 @@
EXPORT_SYMBOL_GPL(svc_max_payload);
/**
+ * svc_encode_read_payload - mark a range of bytes as a READ payload
+ * @rqstp: svc_rqst to operate on
+ * @offset: payload's byte offset in rqstp->rq_res
+ * @length: size of payload, in bytes
+ *
+ * Returns zero on success, or a negative errno if a permanent
+ * error occurred.
+ */
+int svc_encode_read_payload(struct svc_rqst *rqstp, unsigned int offset,
+ unsigned int length)
+{
+ return rqstp->rq_xprt->xpt_ops->xpo_read_payload(rqstp, offset, length);
+}
+EXPORT_SYMBOL_GPL(svc_encode_read_payload);
+
+/**
* svc_fill_write_vector - Construct data argument for VFS write call
* @rqstp: svc_rqst to operate on
* @pages: list of pages containing data payload
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 4260924..d52abde 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -279,6 +279,12 @@
return len;
}
+static int svc_sock_read_payload(struct svc_rqst *rqstp, unsigned int offset,
+ unsigned int length)
+{
+ return 0;
+}
+
/*
* Report socket names for nfsdfs
*/
@@ -655,6 +661,7 @@
.xpo_create = svc_udp_create,
.xpo_recvfrom = svc_udp_recvfrom,
.xpo_sendto = svc_udp_sendto,
+ .xpo_read_payload = svc_sock_read_payload,
.xpo_release_rqst = svc_release_udp_skb,
.xpo_detach = svc_sock_detach,
.xpo_free = svc_sock_free,
@@ -1175,6 +1182,7 @@
.xpo_create = svc_tcp_create,
.xpo_recvfrom = svc_tcp_recvfrom,
.xpo_sendto = svc_tcp_sendto,
+ .xpo_read_payload = svc_sock_read_payload,
.xpo_release_rqst = svc_release_skb,
.xpo_detach = svc_tcp_sock_detach,
.xpo_free = svc_sock_free,
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index b8ee91f..0ce4e75 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -193,6 +193,7 @@
out:
ctxt->rc_page_count = 0;
+ ctxt->rc_read_payload_length = 0;
return ctxt;
out_empty:
diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
index a59912e..066af6b 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
@@ -481,18 +481,19 @@
vec->iov_len);
}
-/* Send an xdr_buf's page list by itself. A Write chunk is
- * just the page list. a Reply chunk is the head, page list,
- * and tail. This function is shared between the two types
- * of chunk.
+/* Send an xdr_buf's page list by itself. A Write chunk is just
+ * the page list. A Reply chunk is @xdr's head, page list, and
+ * tail. This function is shared between the two types of chunk.
*/
static int svc_rdma_send_xdr_pagelist(struct svc_rdma_write_info *info,
- struct xdr_buf *xdr)
+ struct xdr_buf *xdr,
+ unsigned int offset,
+ unsigned long length)
{
info->wi_xdr = xdr;
- info->wi_next_off = 0;
+ info->wi_next_off = offset - xdr->head[0].iov_len;
return svc_rdma_build_writes(info, svc_rdma_pagelist_to_sg,
- xdr->page_len);
+ length);
}
/**
@@ -500,6 +501,8 @@
* @rdma: controlling RDMA transport
* @wr_ch: Write chunk provided by client
* @xdr: xdr_buf containing the data payload
+ * @offset: payload's byte offset in @xdr
+ * @length: size of payload, in bytes
*
* Returns a non-negative number of bytes the chunk consumed, or
* %-E2BIG if the payload was larger than the Write chunk,
@@ -509,19 +512,20 @@
* %-EIO if rdma_rw initialization failed (DMA mapping, etc).
*/
int svc_rdma_send_write_chunk(struct svcxprt_rdma *rdma, __be32 *wr_ch,
- struct xdr_buf *xdr)
+ struct xdr_buf *xdr,
+ unsigned int offset, unsigned long length)
{
struct svc_rdma_write_info *info;
int ret;
- if (!xdr->page_len)
+ if (!length)
return 0;
info = svc_rdma_write_info_alloc(rdma, wr_ch);
if (!info)
return -ENOMEM;
- ret = svc_rdma_send_xdr_pagelist(info, xdr);
+ ret = svc_rdma_send_xdr_pagelist(info, xdr, offset, length);
if (ret < 0)
goto out_err;
@@ -530,7 +534,7 @@
goto out_err;
trace_svcrdma_encode_write(xdr->page_len);
- return xdr->page_len;
+ return length;
out_err:
svc_rdma_write_info_free(info);
@@ -570,7 +574,9 @@
* client did not provide Write chunks.
*/
if (!writelist && xdr->page_len) {
- ret = svc_rdma_send_xdr_pagelist(info, xdr);
+ ret = svc_rdma_send_xdr_pagelist(info, xdr,
+ xdr->head[0].iov_len,
+ xdr->page_len);
if (ret < 0)
goto out_err;
consumed += xdr->page_len;
diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 93ff796..217106c 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -856,7 +856,18 @@
if (wr_lst) {
/* XXX: Presume the client sent only one Write chunk */
- ret = svc_rdma_send_write_chunk(rdma, wr_lst, xdr);
+ unsigned long offset;
+ unsigned int length;
+
+ if (rctxt->rc_read_payload_length) {
+ offset = rctxt->rc_read_payload_offset;
+ length = rctxt->rc_read_payload_length;
+ } else {
+ offset = xdr->head[0].iov_len;
+ length = xdr->page_len;
+ }
+ ret = svc_rdma_send_write_chunk(rdma, wr_lst, xdr, offset,
+ length);
if (ret < 0)
goto err2;
svc_rdma_xdr_encode_write_list(rdma_resp, wr_lst, ret);
@@ -891,3 +902,30 @@
set_bit(XPT_CLOSE, &xprt->xpt_flags);
return -ENOTCONN;
}
+
+/**
+ * svc_rdma_read_payload - special processing for a READ payload
+ * @rqstp: svc_rqst to operate on
+ * @offset: payload's byte offset in @xdr
+ * @length: size of payload, in bytes
+ *
+ * Returns zero on success.
+ *
+ * For the moment, just record the xdr_buf location of the READ
+ * payload. svc_rdma_sendto will use that location later when
+ * we actually send the payload.
+ */
+int svc_rdma_read_payload(struct svc_rqst *rqstp, unsigned int offset,
+ unsigned int length)
+{
+ struct svc_rdma_recv_ctxt *rctxt = rqstp->rq_xprt_ctxt;
+
+ /* XXX: Just one READ payload slot for now, since our
+ * transport implementation currently supports only one
+ * Write chunk.
+ */
+ rctxt->rc_read_payload_offset = offset;
+ rctxt->rc_read_payload_length = length;
+
+ return 0;
+}
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 889220f..89a1267 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -81,6 +81,7 @@
.xpo_create = svc_rdma_create,
.xpo_recvfrom = svc_rdma_recvfrom,
.xpo_sendto = svc_rdma_sendto,
+ .xpo_read_payload = svc_rdma_read_payload,
.xpo_release_rqst = svc_rdma_release_rqst,
.xpo_detach = svc_rdma_detach,
.xpo_free = svc_rdma_free,
