Commit 1c6dcbe5 authored by Anna Schumaker's avatar Anna Schumaker Committed by Trond Myklebust
Browse files

NFS: Implement SEEK 



The SEEK operation is used when an application makes an lseek call with
either the SEEK_HOLE or SEEK_DATA flags set.  I fall back on
nfs_file_llseek() if the server does not have SEEK support.

Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 4a3a0eba

fs/nfs/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ nfsv4-y := nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o nfs4super.o nfs4file.o 
nfsv4-$(CONFIG_NFS_USE_LEGACY_DNS) += cache_lib.o

nfsv4-$(CONFIG_SYSCTL)	+= nfs4sysctl.o

nfsv4-$(CONFIG_NFS_V4_1)	+= pnfs.o pnfs_dev.o

nfsv4-$(CONFIG_NFS_V4_2)	+= nfs42proc.o



obj-$(CONFIG_PNFS_FILE_LAYOUT) += filelayout/

obj-$(CONFIG_PNFS_OBJLAYOUT) += objlayout/

fs/nfs/inode.c

+2 −0
Original line number Diff line number Diff line
@@ -716,6 +716,7 @@ struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx) 
	kfree(new);

	return res;

}

EXPORT_SYMBOL_GPL(nfs_get_lock_context);



void nfs_put_lock_context(struct nfs_lock_context *l_ctx)

{
@@ -728,6 +729,7 @@ void nfs_put_lock_context(struct nfs_lock_context *l_ctx) 
	spin_unlock(&inode->i_lock);

	kfree(l_ctx);

}

EXPORT_SYMBOL_GPL(nfs_put_lock_context);



/**

 * nfs_close_context - Common close_context() routine NFSv2/v3

fs/nfs/nfs42.h

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+14 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2014 Anna Schumaker <Anna.Schumaker@Netapp.com>

 */



#ifndef __LINUX_FS_NFS_NFS4_2_H

#define __LINUX_FS_NFS_NFS4_2_H



/* nfs4.2proc.c */

loff_t nfs42_proc_llseek(struct file *, loff_t, int);



/* nfs4.2xdr.h */

extern struct rpc_procinfo nfs4_2_procedures[];



#endif /* __LINUX_FS_NFS_NFS4_2_H */

fs/nfs/nfs42proc.c

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+69 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2014 Anna Schumaker <Anna.Schumaker@Netapp.com>

 */

#include <linux/fs.h>

#include <linux/sunrpc/sched.h>

#include <linux/nfs.h>

#include <linux/nfs3.h>

#include <linux/nfs4.h>

#include <linux/nfs_xdr.h>

#include <linux/nfs_fs.h>

#include "nfs4_fs.h"

#include "nfs42.h"



static int nfs42_set_rw_stateid(nfs4_stateid *dst, struct file *file,

				fmode_t fmode)

{

	struct nfs_open_context *open;

	struct nfs_lock_context *lock;

	int ret;



	open = get_nfs_open_context(nfs_file_open_context(file));

	lock = nfs_get_lock_context(open);

	if (IS_ERR(lock)) {

		put_nfs_open_context(open);

		return PTR_ERR(lock);

	}



	ret = nfs4_set_rw_stateid(dst, open, lock, fmode);



	nfs_put_lock_context(lock);

	put_nfs_open_context(open);

	return ret;

}



loff_t nfs42_proc_llseek(struct file *filep, loff_t offset, int whence)

{

	struct inode *inode = file_inode(filep);

	struct nfs42_seek_args args = {

		.sa_fh		= NFS_FH(inode),

		.sa_offset	= offset,

		.sa_what	= (whence == SEEK_HOLE) ?

					NFS4_CONTENT_HOLE : NFS4_CONTENT_DATA,

	};

	struct nfs42_seek_res res;

	struct rpc_message msg = {

		.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SEEK],

		.rpc_argp = &args,

		.rpc_resp = &res,

	};

	struct nfs_server *server = NFS_SERVER(inode);

	int status;



	if (!(server->caps & NFS_CAP_SEEK))

		return -ENOTSUPP;



	status = nfs42_set_rw_stateid(&args.sa_stateid, filep, FMODE_READ);

	if (status)

		return status;



	nfs_wb_all(inode);

	status = nfs4_call_sync(server->client, server, &msg,

				&args.seq_args, &res.seq_res, 0);

	if (status == -ENOTSUPP)

		server->caps &= ~NFS_CAP_SEEK;

	if (status)

		return status;



	return vfs_setpos(filep, res.sr_offset, inode->i_sb->s_maxbytes);

}

fs/nfs/nfs42xdr.c

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+98 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2014 Anna Schumaker <Anna.Schumaker@Netapp.com>

 */

#ifndef __LINUX_FS_NFS_NFS4_2XDR_H

#define __LINUX_FS_NFS_NFS4_2XDR_H



#define encode_seek_maxsz		(op_encode_hdr_maxsz + \

					 encode_stateid_maxsz + \

					 2 /* offset */ + \

					 1 /* whence */)

#define decode_seek_maxsz		(op_decode_hdr_maxsz + \

					 1 /* eof */ + \

					 1 /* whence */ + \

					 2 /* offset */ + \

					 2 /* length */)



#define NFS4_enc_seek_sz		(compound_encode_hdr_maxsz + \

					 encode_putfh_maxsz + \

					 encode_seek_maxsz)

#define NFS4_dec_seek_sz		(compound_decode_hdr_maxsz + \

					 decode_putfh_maxsz + \

					 decode_seek_maxsz)





static void encode_seek(struct xdr_stream *xdr,

			struct nfs42_seek_args *args,

			struct compound_hdr *hdr)

{

	encode_op_hdr(xdr, OP_SEEK, decode_seek_maxsz, hdr);

	encode_nfs4_stateid(xdr, &args->sa_stateid);

	encode_uint64(xdr, args->sa_offset);

	encode_uint32(xdr, args->sa_what);

}



/*

 * Encode SEEK request

 */

static void nfs4_xdr_enc_seek(struct rpc_rqst *req,

			      struct xdr_stream *xdr,

			      struct nfs42_seek_args *args)

{

	struct compound_hdr hdr = {

		.minorversion = nfs4_xdr_minorversion(&args->seq_args),

	};



	encode_compound_hdr(xdr, req, &hdr);

	encode_sequence(xdr, &args->seq_args, &hdr);

	encode_putfh(xdr, args->sa_fh, &hdr);

	encode_seek(xdr, args, &hdr);

	encode_nops(&hdr);

}



static int decode_seek(struct xdr_stream *xdr, struct nfs42_seek_res *res)

{

	int status;

	__be32 *p;



	status = decode_op_hdr(xdr, OP_SEEK);

	if (status)

		return status;



	p = xdr_inline_decode(xdr, 4 + 8);

	if (unlikely(!p))

		goto out_overflow;



	res->sr_eof = be32_to_cpup(p++);

	p = xdr_decode_hyper(p, &res->sr_offset);

	return 0;



out_overflow:

	print_overflow_msg(__func__, xdr);

	return -EIO;

}



/*

 * Decode SEEK request

 */

static int nfs4_xdr_dec_seek(struct rpc_rqst *rqstp,

			     struct xdr_stream *xdr,

			     struct nfs42_seek_res *res)

{

	struct compound_hdr hdr;

	int status;



	status = decode_compound_hdr(xdr, &hdr);

	if (status)

		goto out;

	status = decode_sequence(xdr, &res->seq_res, rqstp);

	if (status)

		goto out;

	status = decode_putfh(xdr);

	if (status)

		goto out;

	status = decode_seek(xdr, res);

out:

	return status;

}

#endif /* __LINUX_FS_NFS_NFS4_2XDR_H */