Hi Bruce-
As we discussed, here are a couple of minor improvements for the
xdr_stream_subsegment() API added when the NFSv4 XDR functions were
recently overhauled. Notably, the second patch changes the NFSv2 and
NFSv3 decoders to work like the NFSv4 one.
---
Chuck Lever (2):
SUNRPC: xdr_stream_subsegment() must handle non-zero page_bases
NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment()
fs/nfsd/nfs3proc.c | 3 +--
fs/nfsd/nfs3xdr.c | 12 ++----------
fs/nfsd/nfs4proc.c | 3 +--
fs/nfsd/nfsproc.c | 3 +--
fs/nfsd/nfsxdr.c | 9 +--------
fs/nfsd/xdr.h | 2 +-
fs/nfsd/xdr3.h | 2 +-
include/linux/sunrpc/svc.h | 3 +--
net/sunrpc/svc.c | 11 ++++++-----
net/sunrpc/xdr.c | 32 +++++++++++++++++---------------
10 files changed, 32 insertions(+), 48 deletions(-)
--
Chuck Lever
Refactor.
Now that the NFSv2 and NFSv3 XDR decoders have been converted to
use xdr_streams, the WRITE decoder functions can use
xdr_stream_subsegment() to extract the WRITE payload into its own
xdr_buf, just as the NFSv4 WRITE XDR decoder currently does.
That makes it possible to pass the first kvec, pages array + length,
page_base, and total payload length via a single function parameter.
The payload's page_base is not yet assigned or used, but will be in
subsequent patches.
Signed-off-by: Chuck Lever <[email protected]>
---
fs/nfsd/nfs3proc.c | 3 +--
fs/nfsd/nfs3xdr.c | 12 ++----------
fs/nfsd/nfs4proc.c | 3 +--
fs/nfsd/nfsproc.c | 3 +--
fs/nfsd/nfsxdr.c | 9 +--------
fs/nfsd/xdr.h | 2 +-
fs/nfsd/xdr3.h | 2 +-
include/linux/sunrpc/svc.h | 3 +--
net/sunrpc/svc.c | 11 ++++++-----
9 files changed, 15 insertions(+), 33 deletions(-)
diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 17715a6c7a40..4418517f6f12 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -201,8 +201,7 @@ nfsd3_proc_write(struct svc_rqst *rqstp)
fh_copy(&resp->fh, &argp->fh);
resp->committed = argp->stable;
- nvecs = svc_fill_write_vector(rqstp, rqstp->rq_arg.pages,
- &argp->first, cnt);
+ nvecs = svc_fill_write_vector(rqstp, &argp->payload);
if (!nvecs) {
resp->status = nfserr_io;
goto out;
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 0a5ebc52e6a9..91d4e2b8b854 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -621,9 +621,6 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct nfsd3_writeargs *args = rqstp->rq_argp;
u32 max_blocksize = svc_max_payload(rqstp);
- struct kvec *head = rqstp->rq_arg.head;
- struct kvec *tail = rqstp->rq_arg.tail;
- size_t remaining;
if (!svcxdr_decode_nfs_fh3(xdr, &args->fh))
return 0;
@@ -641,17 +638,12 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
/* request sanity */
if (args->count != args->len)
return 0;
- remaining = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len;
- remaining -= xdr_stream_pos(xdr);
- if (remaining < xdr_align_size(args->len))
- return 0;
if (args->count > max_blocksize) {
args->count = max_blocksize;
args->len = max_blocksize;
}
-
- args->first.iov_base = xdr->p;
- args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
+ if (!xdr_stream_subsegment(xdr, &args->payload, args->count))
+ return 0;
return 1;
}
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 486c5dba4b65..55c9551fa74e 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1033,8 +1033,7 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
write->wr_how_written = write->wr_stable_how;
- nvecs = svc_fill_write_vector(rqstp, write->wr_payload.pages,
- write->wr_payload.head, write->wr_buflen);
+ nvecs = svc_fill_write_vector(rqstp, &write->wr_payload);
WARN_ON_ONCE(nvecs > ARRAY_SIZE(rqstp->rq_vec));
status = nfsd_vfs_write(rqstp, &cstate->current_fh, nf,
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 90fcd6178823..eea5b59b6a6c 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -234,8 +234,7 @@ nfsd_proc_write(struct svc_rqst *rqstp)
SVCFH_fmt(&argp->fh),
argp->len, argp->offset);
- nvecs = svc_fill_write_vector(rqstp, rqstp->rq_arg.pages,
- &argp->first, cnt);
+ nvecs = svc_fill_write_vector(rqstp, &argp->payload);
if (!nvecs) {
resp->status = nfserr_io;
goto out;
diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index a06c05fe3b42..26a42f87c240 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -325,10 +325,7 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
{
struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct nfsd_writeargs *args = rqstp->rq_argp;
- struct kvec *head = rqstp->rq_arg.head;
- struct kvec *tail = rqstp->rq_arg.tail;
u32 beginoffset, totalcount;
- size_t remaining;
if (!svcxdr_decode_fhandle(xdr, &args->fh))
return 0;
@@ -346,12 +343,8 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
return 0;
if (args->len > NFSSVC_MAXBLKSIZE_V2)
return 0;
- remaining = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len;
- remaining -= xdr_stream_pos(xdr);
- if (remaining < xdr_align_size(args->len))
+ if (!xdr_stream_subsegment(xdr, &args->payload, args->len))
return 0;
- args->first.iov_base = xdr->p;
- args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
return 1;
}
diff --git a/fs/nfsd/xdr.h b/fs/nfsd/xdr.h
index f45b4bc93f52..80fd6d7f3404 100644
--- a/fs/nfsd/xdr.h
+++ b/fs/nfsd/xdr.h
@@ -33,7 +33,7 @@ struct nfsd_writeargs {
svc_fh fh;
__u32 offset;
int len;
- struct kvec first;
+ struct xdr_buf payload;
};
struct nfsd_createargs {
diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h
index 933008382bbe..712c117300cb 100644
--- a/fs/nfsd/xdr3.h
+++ b/fs/nfsd/xdr3.h
@@ -40,7 +40,7 @@ struct nfsd3_writeargs {
__u32 count;
int stable;
__u32 len;
- struct kvec first;
+ struct xdr_buf payload;
};
struct nfsd3_createargs {
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 064c96157d1f..6263410c948a 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -532,8 +532,7 @@ int svc_encode_result_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);
+ struct xdr_buf *payload);
char *svc_fill_symlink_pathname(struct svc_rqst *rqstp,
struct kvec *first, void *p,
size_t total);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index a3bbe5ce4570..08ca797bb8a4 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1676,16 +1676,17 @@ EXPORT_SYMBOL_GPL(svc_encode_result_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
- * @first: buffer containing first section of write payload
- * @total: total number of bytes of write payload
+ * @payload: xdr_buf containing only the write data payload
*
* Fills in rqstp::rq_vec, and returns the number of elements.
*/
-unsigned int svc_fill_write_vector(struct svc_rqst *rqstp, struct page **pages,
- struct kvec *first, size_t total)
+unsigned int svc_fill_write_vector(struct svc_rqst *rqstp,
+ struct xdr_buf *payload)
{
+ struct page **pages = payload->pages;
+ struct kvec *first = payload->head;
struct kvec *vec = rqstp->rq_vec;
+ size_t total = payload->len;
unsigned int i;
/* Some types of transport can present the write payload
xdr_stream_subsegment() was introduced in commit c1346a1216ab
("NFSD: Replace the internals of the READ_BUF() macro").
There are two call sites for xdr_stream_subsegment(). One is
nfsd4_decode_write(), and the other is nfsd4_decode_setxattr().
Currently neither of these call sites calls this API when
xdr_buf::page_base is a non-zero value.
However, I'm about to add a case where page_base will sometimes not
be zero when nfsd4_decode_write() invokes this API. Replace the
logic in xdr_stream_subsegment() that advances to the next data item
in the xdr_stream with something more generic in order to handle
this new use case.
Signed-off-by: Chuck Lever <[email protected]>
---
net/sunrpc/xdr.c | 32 +++++++++++++++++---------------
1 file changed, 17 insertions(+), 15 deletions(-)
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index ca10ba2626f2..df194cc07035 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -1633,7 +1633,7 @@ EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
* Sets up @subbuf to represent a portion of @xdr. The portion
* starts at the current offset in @xdr, and extends for a length
* of @nbytes. If this is successful, @xdr is advanced to the next
- * position following that portion.
+ * XDR data item following that portion.
*
* Return values:
* %true: @subbuf has been initialized, and @xdr has been advanced.
@@ -1642,29 +1642,31 @@ EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
unsigned int nbytes)
{
- unsigned int remaining, offset, len;
+ unsigned int start = xdr_stream_pos(xdr);
+ unsigned int remaining, len;
- if (xdr_buf_subsegment(xdr->buf, subbuf, xdr_stream_pos(xdr), nbytes))
+ /* Extract @subbuf and bounds-check the fn arguments */
+ if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
return false;
- if (subbuf->head[0].iov_len)
- if (!__xdr_inline_decode(xdr, subbuf->head[0].iov_len))
- return false;
-
- remaining = subbuf->page_len;
- offset = subbuf->page_base;
- while (remaining) {
- len = min_t(unsigned int, remaining, PAGE_SIZE) - offset;
-
+ /* Advance @xdr by @nbytes */
+ for (remaining = nbytes; remaining;) {
if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
return false;
- if (!__xdr_inline_decode(xdr, len))
- return false;
+ len = (char *)xdr->end - (char *)xdr->p;
+ if (remaining <= len) {
+ xdr->p = (__be32 *)((char *)xdr->p +
+ (remaining + xdr_pad_size(nbytes)));
+ break;
+ }
+
+ xdr->p = (__be32 *)((char *)xdr->p + len);
+ xdr->end = xdr->p;
remaining -= len;
- offset = 0;
}
+ xdr_stream_set_pos(xdr, start + nbytes);
return true;
}
EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
On Thu, Sep 30, 2021 at 05:06:09PM -0400, Chuck Lever wrote:
> As we discussed, here are a couple of minor improvements for the
> xdr_stream_subsegment() API added when the NFSv4 XDR functions were
> recently overhauled. Notably, the second patch changes the NFSv2 and
> NFSv3 decoders to work like the NFSv4 one.
Looks good to me; applying.
--b.
>
> ---
>
> Chuck Lever (2):
> SUNRPC: xdr_stream_subsegment() must handle non-zero page_bases
> NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment()
>
>
> fs/nfsd/nfs3proc.c | 3 +--
> fs/nfsd/nfs3xdr.c | 12 ++----------
> fs/nfsd/nfs4proc.c | 3 +--
> fs/nfsd/nfsproc.c | 3 +--
> fs/nfsd/nfsxdr.c | 9 +--------
> fs/nfsd/xdr.h | 2 +-
> fs/nfsd/xdr3.h | 2 +-
> include/linux/sunrpc/svc.h | 3 +--
> net/sunrpc/svc.c | 11 ++++++-----
> net/sunrpc/xdr.c | 32 +++++++++++++++++---------------
> 10 files changed, 32 insertions(+), 48 deletions(-)
>
> --
> Chuck Lever