From: Chuck Lever <chuck.lever@xxxxxxxxxx>
Accrue the following benefits:
a) Deduplicate this common bit of code.
b) Don't prepare rq_vec for NFSv2 and NFSv3 spliced reads, which
don't use rq_vec. This is already the case for
nfsd4_encode_read().
c) Eventually, converting NFSD's read path to use a bvec iterator
will be simpler.
In the next patch, nfsd_iter_read() will replace nfsd_readv() for
all NFS versions.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfsd/nfs3proc.c | 14 +----------
fs/nfsd/nfsproc.c | 14 +----------
fs/nfsd/vfs.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++------
fs/nfsd/vfs.h | 8 +++++-
4 files changed, 68 insertions(+), 36 deletions(-)
diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index e6bb8eeb5bc2..fc8d5b7db9f8 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -151,8 +151,6 @@ nfsd3_proc_read(struct svc_rqst *rqstp)
{
struct nfsd3_readargs *argp = rqstp->rq_argp;
struct nfsd3_readres *resp = rqstp->rq_resp;
- unsigned int len;
- int v;
dprintk("nfsd: READ(3) %s %lu bytes at %Lu\n",
SVCFH_fmt(&argp->fh),
@@ -166,17 +164,7 @@ nfsd3_proc_read(struct svc_rqst *rqstp)
if (argp->offset + argp->count > (u64)OFFSET_MAX)
argp->count = (u64)OFFSET_MAX - argp->offset;
- v = 0;
- len = argp->count;
resp->pages = rqstp->rq_next_page;
- while (len > 0) {
- struct page *page = *(rqstp->rq_next_page++);
-
- rqstp->rq_vec[v].iov_base = page_address(page);
- rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
- len -= rqstp->rq_vec[v].iov_len;
- v++;
- }
/* Obtain buffer pointer for payload.
* 1 (status) + 22 (post_op_attr) + 1 (count) + 1 (eof)
@@ -187,7 +175,7 @@ nfsd3_proc_read(struct svc_rqst *rqstp)
fh_copy(&resp->fh, &argp->fh);
resp->status = nfsd_read(rqstp, &resp->fh, argp->offset,
- rqstp->rq_vec, v, &resp->count, &resp->eof);
+ &resp->count, &resp->eof);
return rpc_success;
}
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index c37195572fd0..a7315928a760 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -176,9 +176,7 @@ nfsd_proc_read(struct svc_rqst *rqstp)
{
struct nfsd_readargs *argp = rqstp->rq_argp;
struct nfsd_readres *resp = rqstp->rq_resp;
- unsigned int len;
u32 eof;
- int v;
dprintk("nfsd: READ %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh),
@@ -187,17 +185,7 @@ nfsd_proc_read(struct svc_rqst *rqstp)
argp->count = min_t(u32, argp->count, NFSSVC_MAXBLKSIZE_V2);
argp->count = min_t(u32, argp->count, rqstp->rq_res.buflen);
- v = 0;
- len = argp->count;
resp->pages = rqstp->rq_next_page;
- while (len > 0) {
- struct page *page = *(rqstp->rq_next_page++);
-
- rqstp->rq_vec[v].iov_base = page_address(page);
- rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
- len -= rqstp->rq_vec[v].iov_len;
- v++;
- }
/* Obtain buffer pointer for payload. 19 is 1 word for
* status, 17 words for fattr, and 1 word for the byte count.
@@ -207,7 +195,7 @@ nfsd_proc_read(struct svc_rqst *rqstp)
resp->count = argp->count;
fh_copy(&resp->fh, &argp->fh);
resp->status = nfsd_read(rqstp, &resp->fh, argp->offset,
- rqstp->rq_vec, v, &resp->count, &eof);
+ &resp->count, &eof);
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 c4ef24c5ffd0..054d58d01299 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1028,6 +1028,50 @@ __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
}
+/**
+ * nfsd_iter_read - Perform a VFS read using an iterator
+ * @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
+ * @base: offset in first page of read buffer
+ * @eof: OUT: set non-zero if operation reached the end of the file
+ *
+ * Some filesystems or situations cannot use nfsd_splice_read. This
+ * function is the slightly less-performant fallback for those cases.
+ *
+ * Returns nfs_ok on success, otherwise an nfserr stat value is
+ * returned.
+ */
+__be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
+ struct file *file, loff_t offset, unsigned long *count,
+ unsigned int base, u32 *eof)
+{
+ unsigned long v, total;
+ struct iov_iter iter;
+ loff_t ppos = offset;
+ struct page *page;
+ ssize_t host_err;
+
+ v = 0;
+ total = *count;
+ while (total) {
+ page = *(rqstp->rq_next_page++);
+ rqstp->rq_vec[v].iov_base = page_address(page) + base;
+ rqstp->rq_vec[v].iov_len = min_t(size_t, total, PAGE_SIZE - base);
+ total -= rqstp->rq_vec[v].iov_len;
+ ++v;
+ base = 0;
+ }
+ WARN_ON_ONCE(v > ARRAY_SIZE(rqstp->rq_vec));
+
+ trace_nfsd_read_vector(rqstp, fhp, offset, *count);
+ iov_iter_kvec(&iter, ITER_DEST, rqstp->rq_vec, v, *count);
+ host_err = vfs_iter_read(file, &iter, &ppos, 0);
+ return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
+}
+
/*
* Gathered writes: If another process is currently writing to the file,
* there's a high chance this is another nfsd (triggered by a bulk write
@@ -1153,14 +1197,24 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
return nfserr;
}
-/*
- * Read data from a file. count must contain the requested read count
- * on entry. On return, *count contains the number of bytes actually read.
+/**
+ * nfsd_read - Read data from a file
+ * @rqstp: RPC transaction context
+ * @fhp: file handle 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
+ *
+ * The caller must verify that there is enough space in @rqstp.rq_res
+ * to perform this operation.
+ *
* N.B. After this call fhp needs an fh_put
+ *
+ * Returns nfs_ok on success, otherwise an nfserr stat value is
+ * returned.
*/
__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
- loff_t offset, struct kvec *vec, int vlen, unsigned long *count,
- u32 *eof)
+ loff_t offset, unsigned long *count, u32 *eof)
{
struct nfsd_file *nf;
struct file *file;
@@ -1175,12 +1229,10 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
else
- err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof);
+ err = nfsd_iter_read(rqstp, fhp, file, offset, count, 0, eof);
nfsd_file_put(nf);
-
trace_nfsd_read_done(rqstp, fhp, offset, *count);
-
return err;
}
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index 43fb57a301d3..6381a2890b0b 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -115,8 +115,12 @@ __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct kvec *vec, int vlen,
unsigned long *count,
u32 *eof);
-__be32 nfsd_read(struct svc_rqst *, struct svc_fh *,
- loff_t, struct kvec *, int, unsigned long *,
+__be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
+ struct file *file, loff_t offset,
+ unsigned long *count, unsigned int base,
+ u32 *eof);
+__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 *,
