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linux-next/include/linux/nfs_mount.h
Trond Myklebust 75180df2ed NFS: Add the mount option "nosharecache"
Prior to David Howell's mount changes in 2.6.18, users who mounted
different directories which happened to be from the same filesystem on the
server would get different super blocks, and hence could choose different
mount options. As long as there were no hard linked files that crossed from
one subtree to another, this was quite safe.
Post the changes, if the two directories are on the same filesystem (have
the same 'fsid'), they will share the same super block, and hence the same
mount options.

Add a flag to allow users to elect not to share the NFS super block with
another mount point, even if the fsids are the same. This will allow
users to set different mount options for the two different super blocks, as
was previously possible. It is still up to the user to ensure that there
are no cache coherency issues when doing this, however the default
behaviour will be to share super blocks whenever two paths result in
the same fsid.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:48 -04:00

69 lines
2.0 KiB
C

#ifndef _LINUX_NFS_MOUNT_H
#define _LINUX_NFS_MOUNT_H
/*
* linux/include/linux/nfs_mount.h
*
* Copyright (C) 1992 Rick Sladkey
*
* structure passed from user-space to kernel-space during an nfs mount
*/
#include <linux/in.h>
#include <linux/nfs.h>
#include <linux/nfs2.h>
#include <linux/nfs3.h>
/*
* WARNING! Do not delete or change the order of these fields. If
* a new field is required then add it to the end. The version field
* tracks which fields are present. This will ensure some measure of
* mount-to-kernel version compatibility. Some of these aren't used yet
* but here they are anyway.
*/
#define NFS_MOUNT_VERSION 6
#define NFS_MAX_CONTEXT_LEN 256
struct nfs_mount_data {
int version; /* 1 */
int fd; /* 1 */
struct nfs2_fh old_root; /* 1 */
int flags; /* 1 */
int rsize; /* 1 */
int wsize; /* 1 */
int timeo; /* 1 */
int retrans; /* 1 */
int acregmin; /* 1 */
int acregmax; /* 1 */
int acdirmin; /* 1 */
int acdirmax; /* 1 */
struct sockaddr_in addr; /* 1 */
char hostname[NFS_MAXNAMLEN + 1]; /* 1 */
int namlen; /* 2 */
unsigned int bsize; /* 3 */
struct nfs3_fh root; /* 4 */
int pseudoflavor; /* 5 */
char context[NFS_MAX_CONTEXT_LEN + 1]; /* 6 */
};
/* bits in the flags field */
#define NFS_MOUNT_SOFT 0x0001 /* 1 */
#define NFS_MOUNT_INTR 0x0002 /* 1 */
#define NFS_MOUNT_SECURE 0x0004 /* 1 */
#define NFS_MOUNT_POSIX 0x0008 /* 1 */
#define NFS_MOUNT_NOCTO 0x0010 /* 1 */
#define NFS_MOUNT_NOAC 0x0020 /* 1 */
#define NFS_MOUNT_TCP 0x0040 /* 2 */
#define NFS_MOUNT_VER3 0x0080 /* 3 */
#define NFS_MOUNT_KERBEROS 0x0100 /* 3 */
#define NFS_MOUNT_NONLM 0x0200 /* 3 */
#define NFS_MOUNT_BROKEN_SUID 0x0400 /* 4 */
#define NFS_MOUNT_NOACL 0x0800 /* 4 */
#define NFS_MOUNT_STRICTLOCK 0x1000 /* reserved for NFSv4 */
#define NFS_MOUNT_SECFLAVOUR 0x2000 /* 5 */
#define NFS_MOUNT_NORDIRPLUS 0x4000 /* 5 */
#define NFS_MOUNT_UNSHARED 0x8000 /* 5 */
#define NFS_MOUNT_FLAGMASK 0xFFFF
#endif