Commit 507df40e authored by Chuck Lever's avatar Chuck Lever
Browse files

NFSD: Hoist rq_vec preparation into nfsd_read() 



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: default avatarChuck Lever <chuck.lever@oracle.com>
parent ed4a567a

fs/nfsd/nfs3proc.c

+1 −13
Original line number Diff line number Diff line
@@ -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;

}

fs/nfsd/nfsproc.c

+1 −13
Original line number Diff line number Diff line
@@ -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)

fs/nfsd/vfs.c

+60 −8
Original line number Diff line number Diff line
@@ -1036,6 +1036,50 @@ __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
@@ -1161,14 +1205,24 @@ 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;
@@ -1183,12 +1237,10 @@ __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;

}

fs/nfsd/vfs.h

+6 −2
Original line number Diff line number Diff line
@@ -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 *,