[PATCH v5 07/19] NFSD: De-duplicate the svc_fill_write_vector() call sites

cel
2025-05-09T19:04:02Z

All three call sites do the same thing.

I'm struggling with this a bit, however. struct xdr_buf is an XDR
layer object and unmarshaling a WRITE payload is clearly a task
intended to be done by the proc and xdr functions, not by VFS. This
feels vaguely like a layering violation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/nfsd/nfs3proc.c | 5 +---
fs/nfsd/nfs4proc.c | 8 ++----
fs/nfsd/nfsproc.c | 9 +++----
fs/nfsd/vfs.c | 52 +++++++++++++++++++++++++++++---------
fs/nfsd/vfs.h | 10 ++++----
include/linux/sunrpc/svc.h | 2 +-
net/sunrpc/svc.c | 4 +--
7 files changed, 54 insertions(+), 36 deletions(-)

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 8902fae8c62d..12e1eef810e7 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -220,7 +220,6 @@ nfsd3_proc_write(struct svc_rqst *rqstp)
struct nfsd3_writeargs *argp = rqstp->rq_argp;
struct nfsd3_writeres *resp = rqstp->rq_resp;
unsigned long cnt = argp->len;
- unsigned int nvecs;

dprintk("nfsd: WRITE(3) %s %d bytes at %Lu%s\n",
SVCFH_fmt(&argp->fh),
@@ -235,10 +234,8 @@ nfsd3_proc_write(struct svc_rqst *rqstp)

fh_copy(&resp->fh, &argp->fh);
resp->committed = argp->stable;
- nvecs = svc_fill_write_vector(rqstp, &argp->payload);
-
resp->status = nfsd_write(rqstp, &resp->fh, argp->offset,
- rqstp->rq_vec, nvecs, &cnt,
+ &argp->payload, &cnt,
resp->committed, resp->verf);
resp->count = cnt;
resp->status = nfsd3_map_status(resp->status);
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 2b16ee1ae461..ffd8b1d499df 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1216,7 +1216,6 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
struct nfsd_file *nf = NULL;
__be32 status = nfs_ok;
unsigned long cnt;
- int nvecs;

if (write->wr_offset > (u64)OFFSET_MAX ||
write->wr_offset + write->wr_buflen > (u64)OFFSET_MAX)
@@ -1231,12 +1230,9 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
return status;

write->wr_how_written = write->wr_stable_how;
-
- nvecs = svc_fill_write_vector(rqstp, &write->wr_payload);
-
status = nfsd_vfs_write(rqstp, &cstate->current_fh, nf,
- write->wr_offset, rqstp->rq_vec, nvecs, &cnt,
- write->wr_how_written,
+ write->wr_offset, &write->wr_payload,
+ &cnt, write->wr_how_written,
(__be32 *)write->wr_verifier.data);
nfsd_file_put(nf);

diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 7c573d792252..65cbe04184f3 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -251,17 +251,14 @@ nfsd_proc_write(struct svc_rqst *rqstp)
struct nfsd_writeargs *argp = rqstp->rq_argp;
struct nfsd_attrstat *resp = rqstp->rq_resp;
unsigned long cnt = argp->len;
- unsigned int nvecs;

dprintk("nfsd: WRITE %s %u bytes at %d\n",
SVCFH_fmt(&argp->fh),
argp->len, argp->offset);

- nvecs = svc_fill_write_vector(rqstp, &argp->payload);
-
- resp->status = nfsd_write(rqstp, fh_copy(&resp->fh, &argp->fh),
- argp->offset, rqstp->rq_vec, nvecs,
- &cnt, NFS_DATA_SYNC, NULL);
+ fh_copy(&resp->fh, &argp->fh);
+ resp->status = nfsd_write(rqstp, &resp->fh, argp->offset,
+ &argp->payload, &cnt, NFS_DATA_SYNC, NULL);
if (resp->status == nfs_ok)
resp->status = fh_getattr(&resp->fh, &resp->stat);
else if (resp->status == nfserr_jukebox)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 7cfd26dec5a8..43ecc5ae0c3f 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1143,11 +1143,27 @@ static int wait_for_concurrent_writes(struct file *file)
return err;
}

+/**
+ * nfsd_vfs_write - write data to an already-open file
+ * @rqstp: RPC execution context
+ * @fhp: File handle of file to write into
+ * @nf: An open file matching @fhp
+ * @offset: Byte offset of start
+ * @payload: xdr_buf containing the write payload
+ * @cnt: IN: number of bytes to write, OUT: number of bytes actually written
+ * @stable: An NFS stable_how value
+ * @verf: NFS WRITE verifier
+ *
+ * Upon return, caller must invoke fh_put on @fhp.
+ *
+ * Return values:
+ * An nfsstat value in network byte order.
+ */
__be32
-nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
- loff_t offset, struct kvec *vec, int vlen,
- unsigned long *cnt, int stable,
- __be32 *verf)
+nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp,
+ struct nfsd_file *nf, loff_t offset,
+ const struct xdr_buf *payload, unsigned long *cnt,
+ int stable, __be32 *verf)
{
struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
struct file *file = nf->nf_file;
@@ -1162,6 +1178,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
unsigned int pflags = current->flags;
rwf_t flags = 0;
bool restore_flags = false;
+ unsigned int nvecs;

trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);

@@ -1189,7 +1206,8 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
if (stable && !fhp->fh_use_wgather)
flags |= RWF_SYNC;

- iov_iter_kvec(&iter, ITER_SOURCE, vec, vlen, *cnt);
+ nvecs = svc_fill_write_vector(rqstp, payload);
+ iov_iter_kvec(&iter, ITER_SOURCE, rqstp->rq_vec, nvecs, *cnt);
since = READ_ONCE(file->f_wb_err);
if (verf)
nfsd_copy_write_verifier(verf, nn);
@@ -1289,14 +1307,24 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
return err;
}

-/*
- * Write data to a file.
- * The stable flag requests synchronous writes.
- * N.B. After this call fhp needs an fh_put
+/**
+ * nfsd_write - open a file and write data to it
+ * @rqstp: RPC execution context
+ * @fhp: File handle of file to write into; nfsd_write() may modify it
+ * @offset: Byte offset of start
+ * @payload: xdr_buf containing the write payload
+ * @cnt: IN: number of bytes to write, OUT: number of bytes actually written
+ * @stable: An NFS stable_how value
+ * @verf: NFS WRITE verifier
+ *
+ * Upon return, caller must invoke fh_put on @fhp.
+ *
+ * Return values:
+ * An nfsstat value in network byte order.
*/
__be32
nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
- struct kvec *vec, int vlen, unsigned long *cnt, int stable,
+ const struct xdr_buf *payload, unsigned long *cnt, int stable,
__be32 *verf)
{
struct nfsd_file *nf;
@@ -1308,8 +1336,8 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
if (err)
goto out;

- err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec,
- vlen, cnt, stable, verf);
+ err = nfsd_vfs_write(rqstp, fhp, nf, offset, payload, cnt,
+ stable, verf);
nfsd_file_put(nf);
out:
trace_nfsd_write_done(rqstp, fhp, offset, *cnt);
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index f9b09b842856..eff04959606f 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -128,13 +128,13 @@ bool nfsd_read_splice_ok(struct svc_rqst *rqstp);
__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
loff_t offset, unsigned long *count,
u32 *eof);
-__be32 nfsd_write(struct svc_rqst *, struct svc_fh *, loff_t,
- struct kvec *, int, unsigned long *,
- int stable, __be32 *verf);
+__be32 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp,
+ loff_t offset, const struct xdr_buf *payload,
+ unsigned long *cnt, int stable, __be32 *verf);
__be32 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct nfsd_file *nf, loff_t offset,
- struct kvec *vec, int vlen, unsigned long *cnt,
- int stable, __be32 *verf);
+ const struct xdr_buf *payload,
+ unsigned long *cnt, int stable, __be32 *verf);
__be32 nfsd_readlink(struct svc_rqst *, struct svc_fh *,
char *, int *);
__be32 nfsd_symlink(struct svc_rqst *, struct svc_fh *,
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 538bea716c6b..dec636345ee2 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -471,7 +471,7 @@ 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 xdr_buf *payload);
+ const 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 2c1c4aa93f43..a8861a80bc04 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1727,10 +1727,10 @@ EXPORT_SYMBOL_GPL(svc_encode_result_payload);
* Fills in rqstp::rq_vec, and returns the number of elements.
*/
unsigned int svc_fill_write_vector(struct svc_rqst *rqstp,
- struct xdr_buf *payload)
+ const struct xdr_buf *payload)
{
+ const struct kvec *first = payload->head;
struct page **pages = payload->pages;
- struct kvec *first = payload->head;
struct kvec *vec = rqstp->rq_vec;
size_t total = payload->len;
unsigned int i;
--
2.49.0