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/* SPDX-License-Identifier: GPL-2.0-only */
* V9FS definitions.
* Copyright (C) 2004-2008 by Eric Van Hensbergen <>
* Copyright (C) 2002 by Ron Minnich <>
#ifndef FS_9P_V9FS_H
#define FS_9P_V9FS_H
#include <linux/backing-dev.h>
#include <linux/netfs.h>
* enum p9_session_flags - option flags for each 9P session
* @V9FS_PROTO_2000U: whether or not to use 9P2000.u extensions
* @V9FS_PROTO_2000L: whether or not to use 9P2000.l extensions
* @V9FS_ACCESS_SINGLE: only the mounting user can access the hierarchy
* @V9FS_ACCESS_USER: a new attach will be issued for every user (default)
* @V9FS_ACCESS_CLIENT: Just like user, but access check is performed on client.
* @V9FS_ACCESS_ANY: use a single attach for all users
* @V9FS_ACCESS_MASK: bit mask of different ACCESS options
* @V9FS_POSIX_ACL: POSIX ACLs are enforced
* Session flags reflect options selected by users at mount time
enum p9_session_flags {
V9FS_PROTO_2000U = 0x01,
V9FS_PROTO_2000L = 0x02,
V9FS_POSIX_ACL = 0x20,
V9FS_NO_XATTR = 0x40,
V9FS_IGNORE_QV = 0x80, /* ignore qid.version for cache hints */
V9FS_DIRECT_IO = 0x100,
V9FS_SYNC = 0x200
* enum p9_cache_shortcuts - human readable cache preferences
* @CACHE_SC_NONE: disable all caches
* @CACHE_SC_READAHEAD: only provide caching for readahead
* @CACHE_SC_MMAP: provide caching to enable mmap
* @CACHE_SC_LOOSE: non-coherent caching for files and meta data
* @CACHE_SC_FSCACHE: persistent non-coherent caching for files and meta-data
enum p9_cache_shortcuts {
CACHE_SC_NONE = 0b00000000,
CACHE_SC_READAHEAD = 0b00000001,
CACHE_SC_MMAP = 0b00000101,
CACHE_SC_LOOSE = 0b00001111,
CACHE_SC_FSCACHE = 0b10001111,
* enum p9_cache_bits - possible values of ->cache
* @CACHE_NONE: caches disabled
* @CACHE_FILE: file caching (open to close)
* @CACHE_META: meta-data and directory caching
* @CACHE_WRITEBACK: write-back caching for files
* @CACHE_LOOSE: don't check cache consistency
* @CACHE_FSCACHE: local persistent caches
enum p9_cache_bits {
CACHE_NONE = 0b00000000,
CACHE_FILE = 0b00000001,
CACHE_META = 0b00000010,
CACHE_WRITEBACK = 0b00000100,
CACHE_LOOSE = 0b00001000,
CACHE_FSCACHE = 0b10000000,
* struct v9fs_session_info - per-instance session information
* @flags: session options of type &p9_session_flags
* @nodev: set to 1 to disable device mapping
* @debug: debug level
* @afid: authentication handle
* @cache: cache mode of type &p9_cache_bits
* @cachetag: the tag of the cache associated with this session
* @fscache: session cookie associated with FS-Cache
* @uname: string user name to mount hierarchy as
* @aname: mount specifier for remote hierarchy
* @maxdata: maximum data to be sent/recvd per protocol message
* @dfltuid: default numeric userid to mount hierarchy as
* @dfltgid: default numeric groupid to mount hierarchy as
* @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
* @clnt: reference to 9P network client instantiated for this session
* @slist: reference to list of registered 9p sessions
* This structure holds state for each session instance established during
* a sys_mount() .
* Bugs: there seems to be a lot of state which could be condensed and/or
* removed.
struct v9fs_session_info {
/* options */
unsigned int flags;
unsigned char nodev;
unsigned short debug;
unsigned int afid;
unsigned int cache;
char *cachetag;
struct fscache_volume *fscache;
char *uname; /* user name to mount as */
char *aname; /* name of remote hierarchy being mounted */
unsigned int maxdata; /* max data for client interface */
kuid_t dfltuid; /* default uid/muid for legacy support */
kgid_t dfltgid; /* default gid for legacy support */
kuid_t uid; /* if ACCESS_SINGLE, the uid that has access */
struct p9_client *clnt; /* 9p client */
struct list_head slist; /* list of sessions registered with v9fs */
struct rw_semaphore rename_sem;
long session_lock_timeout; /* retry interval for blocking locks */
/* cache_validity flags */
#define V9FS_INO_INVALID_ATTR 0x01
struct v9fs_inode {
struct netfs_inode netfs; /* Netfslib context and vfs inode */
struct p9_qid qid;
unsigned int cache_validity;
struct mutex v_mutex;
static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
return container_of(inode, struct v9fs_inode, netfs.inode);
static inline struct fscache_cookie *v9fs_inode_cookie(struct v9fs_inode *v9inode)
return netfs_i_cookie(&v9inode->netfs);
return NULL;
static inline struct fscache_volume *v9fs_session_cache(struct v9fs_session_info *v9ses)
return v9ses->fscache;
return NULL;
extern int v9fs_show_options(struct seq_file *m, struct dentry *root);
struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
const char *dev_name, char *data);
extern void v9fs_session_close(struct v9fs_session_info *v9ses);
extern void v9fs_session_cancel(struct v9fs_session_info *v9ses);
extern void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
extern struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags);
extern int v9fs_vfs_unlink(struct inode *i, struct dentry *d);
extern int v9fs_vfs_rmdir(struct inode *i, struct dentry *d);
extern int v9fs_vfs_rename(struct mnt_idmap *idmap,
struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags);
extern struct inode *v9fs_fid_iget(struct super_block *sb, struct p9_fid *fid);
extern const struct inode_operations v9fs_dir_inode_operations_dotl;
extern const struct inode_operations v9fs_file_inode_operations_dotl;
extern const struct inode_operations v9fs_symlink_inode_operations_dotl;
extern const struct netfs_request_ops v9fs_req_ops;
extern struct inode *v9fs_fid_iget_dotl(struct super_block *sb,
struct p9_fid *fid);
/* other default globals */
#define V9FS_PORT 564
#define V9FS_DEFUSER "nobody"
#define V9FS_DEFANAME ""
static inline struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
return inode->i_sb->s_fs_info;
static inline struct v9fs_session_info *v9fs_dentry2v9ses(struct dentry *dentry)
return dentry->d_sb->s_fs_info;
static inline int v9fs_proto_dotu(struct v9fs_session_info *v9ses)
return v9ses->flags & V9FS_PROTO_2000U;
static inline int v9fs_proto_dotl(struct v9fs_session_info *v9ses)
return v9ses->flags & V9FS_PROTO_2000L;
* v9fs_get_inode_from_fid - Helper routine to populate an inode by
* issuing a attribute request
* @v9ses: session information
* @fid: fid to issue attribute request for
* @sb: superblock on which to create inode
static inline struct inode *
v9fs_get_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
struct super_block *sb)
if (v9fs_proto_dotl(v9ses))
return v9fs_fid_iget_dotl(sb, fid);
return v9fs_fid_iget(sb, fid);