fs/9p/v9fs.h

   1 /*
   2  * V9FS definitions.
   3  *
   4  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
   5  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2
   9  *  as published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to:
  18  *  Free Software Foundation
  19  *  51 Franklin Street, Fifth Floor
  20  *  Boston, MA  02111-1301  USA
  21  *
  22  */
  23 #include <linux/backing-dev.h>
  24
  25 /**
  26  * enum p9_session_flags - option flags for each 9P session
  27  * @V9FS_PROTO_2000U: whether or not to use 9P2000.u extensions
  28  * @V9FS_PROTO_2000L: whether or not to use 9P2000.l extensions
  29  * @V9FS_ACCESS_SINGLE: only the mounting user can access the hierarchy
  30  * @V9FS_ACCESS_USER: a new attach will be issued for every user (default)
  31  * @V9FS_ACCESS_ANY: use a single attach for all users
  32  * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
  33  *
  34  * Session flags reflect options selected by users at mount time
  35  */
  36 enum p9_session_flags {
  37         V9FS_PROTO_2000U        = 0x01,
  38         V9FS_PROTO_2000L        = 0x02,
  39         V9FS_ACCESS_SINGLE      = 0x04,
  40         V9FS_ACCESS_USER        = 0x08,
  41         V9FS_ACCESS_ANY         = 0x0C,
  42         V9FS_ACCESS_MASK        = 0x0C,
  43 };
  44
  45 /* possible values of ->cache */
  46 /**
  47  * enum p9_cache_modes - user specified cache preferences
  48  * @CACHE_NONE: do not cache data, dentries, or directory contents (default)
  49  * @CACHE_LOOSE: cache data, dentries, and directory contents w/no consistency
  50  *
  51  * eventually support loose, tight, time, session, default always none
  52  */
  53
  54 enum p9_cache_modes {
  55         CACHE_NONE,
  56         CACHE_LOOSE,
  57         CACHE_FSCACHE,
  58 };
  59
  60 /**
  61  * struct v9fs_session_info - per-instance session information
  62  * @flags: session options of type &p9_session_flags
  63  * @nodev: set to 1 to disable device mapping
  64  * @debug: debug level
  65  * @afid: authentication handle
  66  * @cache: cache mode of type &p9_cache_modes
  67  * @cachetag: the tag of the cache associated with this session
  68  * @fscache: session cookie associated with FS-Cache
  69  * @options: copy of options string given by user
  70  * @uname: string user name to mount hierarchy as
  71  * @aname: mount specifier for remote hierarchy
  72  * @maxdata: maximum data to be sent/recvd per protocol message
  73  * @dfltuid: default numeric userid to mount hierarchy as
  74  * @dfltgid: default numeric groupid to mount hierarchy as
  75  * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
  76  * @clnt: reference to 9P network client instantiated for this session
  77  * @slist: reference to list of registered 9p sessions
  78  *
  79  * This structure holds state for each session instance established during
  80  * a sys_mount() .
  81  *
  82  * Bugs: there seems to be a lot of state which could be condensed and/or
  83  * removed.
  84  */
  85
  86 struct v9fs_session_info {
  87         /* options */
  88         unsigned char flags;
  89         unsigned char nodev;
  90         unsigned short debug;
  91         unsigned int afid;
  92         unsigned int cache;
  93 #ifdef CONFIG_9P_FSCACHE
  94         char *cachetag;
  95         struct fscache_cookie *fscache;
  96 #endif
  97
  98         char *uname;            /* user name to mount as */
  99         char *aname;            /* name of remote hierarchy being mounted */
 100         unsigned int maxdata;   /* max data for client interface */
 101         unsigned int dfltuid;   /* default uid/muid for legacy support */
 102         unsigned int dfltgid;   /* default gid for legacy support */
 103         u32 uid;                /* if ACCESS_SINGLE, the uid that has access */
 104         struct p9_client *clnt; /* 9p client */
 105         struct list_head slist; /* list of sessions registered with v9fs */
 106         struct backing_dev_info bdi;
 107         struct rw_semaphore rename_sem;
 108 };
 109
 110 struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
 111                                                                         char *);
 112 void v9fs_session_close(struct v9fs_session_info *v9ses);
 113 void v9fs_session_cancel(struct v9fs_session_info *v9ses);
 114 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
 115
 116 #define V9FS_MAGIC 0x01021997
 117
 118 /* other default globals */
 119 #define V9FS_PORT       564
 120 #define V9FS_DEFUSER    "nobody"
 121 #define V9FS_DEFANAME   ""
 122 #define V9FS_DEFUID     (-2)
 123 #define V9FS_DEFGID     (-2)
 124
 125 static inline struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
 126 {
 127         return (inode->i_sb->s_fs_info);
 128 }
 129
 130 static inline int v9fs_proto_dotu(struct v9fs_session_info *v9ses)
 131 {
 132         return v9ses->flags & V9FS_PROTO_2000U;
 133 }
 134
 135 static inline int v9fs_proto_dotl(struct v9fs_session_info *v9ses)
 136 {
 137         return v9ses->flags & V9FS_PROTO_2000L;
 138 }