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 #ifndef FS_9P_V9FS_H
24 #define FS_9P_V9FS_H
25 
26 #include <linux/backing-dev.h>
27 
28 /**
29  * enum p9_session_flags - option flags for each 9P session
30  * @V9FS_PROTO_2000U: whether or not to use 9P2000.u extensions
31  * @V9FS_PROTO_2000L: whether or not to use 9P2000.l extensions
32  * @V9FS_ACCESS_SINGLE: only the mounting user can access the hierarchy
33  * @V9FS_ACCESS_USER: a new attach will be issued for every user (default)
34  * @V9FS_ACCESS_CLIENT: Just like user, but access check is performed on client.
35  * @V9FS_ACCESS_ANY: use a single attach for all users
36  * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
37  * @V9FS_POSIX_ACL: POSIX ACLs are enforced
38  *
39  * Session flags reflect options selected by users at mount time
40  */
41 #define	V9FS_ACCESS_ANY (V9FS_ACCESS_SINGLE | \
42 			 V9FS_ACCESS_USER |   \
43 			 V9FS_ACCESS_CLIENT)
44 #define V9FS_ACCESS_MASK V9FS_ACCESS_ANY
45 #define V9FS_ACL_MASK V9FS_POSIX_ACL
46 
47 enum p9_session_flags {
48 	V9FS_PROTO_2000U	= 0x01,
49 	V9FS_PROTO_2000L	= 0x02,
50 	V9FS_ACCESS_SINGLE	= 0x04,
51 	V9FS_ACCESS_USER	= 0x08,
52 	V9FS_ACCESS_CLIENT	= 0x10,
53 	V9FS_POSIX_ACL		= 0x20
54 };
55 
56 /* possible values of ->cache */
57 /**
58  * enum p9_cache_modes - user specified cache preferences
59  * @CACHE_NONE: do not cache data, dentries, or directory contents (default)
60  * @CACHE_LOOSE: cache data, dentries, and directory contents w/no consistency
61  *
62  * eventually support loose, tight, time, session, default always none
63  */
64 
65 enum p9_cache_modes {
66 	CACHE_NONE,
67 	CACHE_MMAP,
68 	CACHE_LOOSE,
69 	CACHE_FSCACHE,
70 	nr__p9_cache_modes
71 };
72 
73 /**
74  * struct v9fs_session_info - per-instance session information
75  * @flags: session options of type &p9_session_flags
76  * @nodev: set to 1 to disable device mapping
77  * @debug: debug level
78  * @afid: authentication handle
79  * @cache: cache mode of type &p9_cache_modes
80  * @cachetag: the tag of the cache associated with this session
81  * @fscache: session cookie associated with FS-Cache
82  * @uname: string user name to mount hierarchy as
83  * @aname: mount specifier for remote hierarchy
84  * @maxdata: maximum data to be sent/recvd per protocol message
85  * @dfltuid: default numeric userid to mount hierarchy as
86  * @dfltgid: default numeric groupid to mount hierarchy as
87  * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
88  * @clnt: reference to 9P network client instantiated for this session
89  * @slist: reference to list of registered 9p sessions
90  *
91  * This structure holds state for each session instance established during
92  * a sys_mount() .
93  *
94  * Bugs: there seems to be a lot of state which could be condensed and/or
95  * removed.
96  */
97 
98 struct v9fs_session_info {
99 	/* options */
100 	unsigned char flags;
101 	unsigned char nodev;
102 	unsigned short debug;
103 	unsigned int afid;
104 	unsigned int cache;
105 #ifdef CONFIG_9P_FSCACHE
106 	char *cachetag;
107 	struct fscache_cookie *fscache;
108 #endif
109 
110 	char *uname;		/* user name to mount as */
111 	char *aname;		/* name of remote hierarchy being mounted */
112 	unsigned int maxdata;	/* max data for client interface */
113 	kuid_t dfltuid;		/* default uid/muid for legacy support */
114 	kgid_t dfltgid;		/* default gid for legacy support */
115 	kuid_t uid;		/* if ACCESS_SINGLE, the uid that has access */
116 	struct p9_client *clnt;	/* 9p client */
117 	struct list_head slist; /* list of sessions registered with v9fs */
118 	struct rw_semaphore rename_sem;
119 	long session_lock_timeout; /* retry interval for blocking locks */
120 };
121 
122 /* cache_validity flags */
123 #define V9FS_INO_INVALID_ATTR 0x01
124 
125 struct v9fs_inode {
126 #ifdef CONFIG_9P_FSCACHE
127 	struct mutex fscache_lock;
128 	struct fscache_cookie *fscache;
129 #endif
130 	struct p9_qid qid;
131 	unsigned int cache_validity;
132 	struct p9_fid *writeback_fid;
133 	struct mutex v_mutex;
134 	struct inode vfs_inode;
135 };
136 
V9FS_I(const struct inode * inode)137 static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
138 {
139 	return container_of(inode, struct v9fs_inode, vfs_inode);
140 }
141 
142 extern int v9fs_show_options(struct seq_file *m, struct dentry *root);
143 
144 struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
145 									char *);
146 extern void v9fs_session_close(struct v9fs_session_info *v9ses);
147 extern void v9fs_session_cancel(struct v9fs_session_info *v9ses);
148 extern void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
149 extern struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
150 			unsigned int flags);
151 extern int v9fs_vfs_unlink(struct inode *i, struct dentry *d);
152 extern int v9fs_vfs_rmdir(struct inode *i, struct dentry *d);
153 extern int v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
154 			   struct inode *new_dir, struct dentry *new_dentry,
155 			   unsigned int flags);
156 extern struct inode *v9fs_inode_from_fid(struct v9fs_session_info *v9ses,
157 					 struct p9_fid *fid,
158 					 struct super_block *sb, int new);
159 extern const struct inode_operations v9fs_dir_inode_operations_dotl;
160 extern const struct inode_operations v9fs_file_inode_operations_dotl;
161 extern const struct inode_operations v9fs_symlink_inode_operations_dotl;
162 extern struct inode *v9fs_inode_from_fid_dotl(struct v9fs_session_info *v9ses,
163 					      struct p9_fid *fid,
164 					      struct super_block *sb, int new);
165 
166 /* other default globals */
167 #define V9FS_PORT	564
168 #define V9FS_DEFUSER	"nobody"
169 #define V9FS_DEFANAME	""
170 #define V9FS_DEFUID	KUIDT_INIT(-2)
171 #define V9FS_DEFGID	KGIDT_INIT(-2)
172 
v9fs_inode2v9ses(struct inode * inode)173 static inline struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
174 {
175 	return (inode->i_sb->s_fs_info);
176 }
177 
v9fs_dentry2v9ses(struct dentry * dentry)178 static inline struct v9fs_session_info *v9fs_dentry2v9ses(struct dentry *dentry)
179 {
180 	return dentry->d_sb->s_fs_info;
181 }
182 
v9fs_proto_dotu(struct v9fs_session_info * v9ses)183 static inline int v9fs_proto_dotu(struct v9fs_session_info *v9ses)
184 {
185 	return v9ses->flags & V9FS_PROTO_2000U;
186 }
187 
v9fs_proto_dotl(struct v9fs_session_info * v9ses)188 static inline int v9fs_proto_dotl(struct v9fs_session_info *v9ses)
189 {
190 	return v9ses->flags & V9FS_PROTO_2000L;
191 }
192 
193 /**
194  * v9fs_get_inode_from_fid - Helper routine to populate an inode by
195  * issuing a attribute request
196  * @v9ses: session information
197  * @fid: fid to issue attribute request for
198  * @sb: superblock on which to create inode
199  *
200  */
201 static inline struct inode *
v9fs_get_inode_from_fid(struct v9fs_session_info * v9ses,struct p9_fid * fid,struct super_block * sb)202 v9fs_get_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
203 			struct super_block *sb)
204 {
205 	if (v9fs_proto_dotl(v9ses))
206 		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 0);
207 	else
208 		return v9fs_inode_from_fid(v9ses, fid, sb, 0);
209 }
210 
211 /**
212  * v9fs_get_new_inode_from_fid - Helper routine to populate an inode by
213  * issuing a attribute request
214  * @v9ses: session information
215  * @fid: fid to issue attribute request for
216  * @sb: superblock on which to create inode
217  *
218  */
219 static inline struct inode *
v9fs_get_new_inode_from_fid(struct v9fs_session_info * v9ses,struct p9_fid * fid,struct super_block * sb)220 v9fs_get_new_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
221 			    struct super_block *sb)
222 {
223 	if (v9fs_proto_dotl(v9ses))
224 		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 1);
225 	else
226 		return v9fs_inode_from_fid(v9ses, fid, sb, 1);
227 }
228 
229 #endif
230