xref: /openbmc/linux/fs/9p/v9fs.h (revision 9cfc5c90)
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 };
71 
72 /**
73  * struct v9fs_session_info - per-instance session information
74  * @flags: session options of type &p9_session_flags
75  * @nodev: set to 1 to disable device mapping
76  * @debug: debug level
77  * @afid: authentication handle
78  * @cache: cache mode of type &p9_cache_modes
79  * @cachetag: the tag of the cache associated with this session
80  * @fscache: session cookie associated with FS-Cache
81  * @uname: string user name to mount hierarchy as
82  * @aname: mount specifier for remote hierarchy
83  * @maxdata: maximum data to be sent/recvd per protocol message
84  * @dfltuid: default numeric userid to mount hierarchy as
85  * @dfltgid: default numeric groupid to mount hierarchy as
86  * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
87  * @clnt: reference to 9P network client instantiated for this session
88  * @slist: reference to list of registered 9p sessions
89  *
90  * This structure holds state for each session instance established during
91  * a sys_mount() .
92  *
93  * Bugs: there seems to be a lot of state which could be condensed and/or
94  * removed.
95  */
96 
97 struct v9fs_session_info {
98 	/* options */
99 	unsigned char flags;
100 	unsigned char nodev;
101 	unsigned short debug;
102 	unsigned int afid;
103 	unsigned int cache;
104 #ifdef CONFIG_9P_FSCACHE
105 	char *cachetag;
106 	struct fscache_cookie *fscache;
107 #endif
108 
109 	char *uname;		/* user name to mount as */
110 	char *aname;		/* name of remote hierarchy being mounted */
111 	unsigned int maxdata;	/* max data for client interface */
112 	kuid_t dfltuid;		/* default uid/muid for legacy support */
113 	kgid_t dfltgid;		/* default gid for legacy support */
114 	kuid_t uid;		/* if ACCESS_SINGLE, the uid that has access */
115 	struct p9_client *clnt;	/* 9p client */
116 	struct list_head slist; /* list of sessions registered with v9fs */
117 	struct backing_dev_info bdi;
118 	struct rw_semaphore rename_sem;
119 };
120 
121 /* cache_validity flags */
122 #define V9FS_INO_INVALID_ATTR 0x01
123 
124 struct v9fs_inode {
125 #ifdef CONFIG_9P_FSCACHE
126 	spinlock_t fscache_lock;
127 	struct fscache_cookie *fscache;
128 #endif
129 	struct p9_qid qid;
130 	unsigned int cache_validity;
131 	struct p9_fid *writeback_fid;
132 	struct mutex v_mutex;
133 	struct inode vfs_inode;
134 };
135 
136 static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
137 {
138 	return container_of(inode, struct v9fs_inode, vfs_inode);
139 }
140 
141 struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
142 									char *);
143 extern void v9fs_session_close(struct v9fs_session_info *v9ses);
144 extern void v9fs_session_cancel(struct v9fs_session_info *v9ses);
145 extern void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
146 extern struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
147 			unsigned int flags);
148 extern int v9fs_vfs_unlink(struct inode *i, struct dentry *d);
149 extern int v9fs_vfs_rmdir(struct inode *i, struct dentry *d);
150 extern int v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
151 			struct inode *new_dir, struct dentry *new_dentry);
152 extern struct inode *v9fs_inode_from_fid(struct v9fs_session_info *v9ses,
153 					 struct p9_fid *fid,
154 					 struct super_block *sb, int new);
155 extern const struct inode_operations v9fs_dir_inode_operations_dotl;
156 extern const struct inode_operations v9fs_file_inode_operations_dotl;
157 extern const struct inode_operations v9fs_symlink_inode_operations_dotl;
158 extern struct inode *v9fs_inode_from_fid_dotl(struct v9fs_session_info *v9ses,
159 					      struct p9_fid *fid,
160 					      struct super_block *sb, int new);
161 
162 /* other default globals */
163 #define V9FS_PORT	564
164 #define V9FS_DEFUSER	"nobody"
165 #define V9FS_DEFANAME	""
166 #define V9FS_DEFUID	KUIDT_INIT(-2)
167 #define V9FS_DEFGID	KGIDT_INIT(-2)
168 
169 static inline struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
170 {
171 	return (inode->i_sb->s_fs_info);
172 }
173 
174 static inline struct v9fs_session_info *v9fs_dentry2v9ses(struct dentry *dentry)
175 {
176 	return dentry->d_sb->s_fs_info;
177 }
178 
179 static inline int v9fs_proto_dotu(struct v9fs_session_info *v9ses)
180 {
181 	return v9ses->flags & V9FS_PROTO_2000U;
182 }
183 
184 static inline int v9fs_proto_dotl(struct v9fs_session_info *v9ses)
185 {
186 	return v9ses->flags & V9FS_PROTO_2000L;
187 }
188 
189 /**
190  * v9fs_get_inode_from_fid - Helper routine to populate an inode by
191  * issuing a attribute request
192  * @v9ses: session information
193  * @fid: fid to issue attribute request for
194  * @sb: superblock on which to create inode
195  *
196  */
197 static inline struct inode *
198 v9fs_get_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
199 			struct super_block *sb)
200 {
201 	if (v9fs_proto_dotl(v9ses))
202 		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 0);
203 	else
204 		return v9fs_inode_from_fid(v9ses, fid, sb, 0);
205 }
206 
207 /**
208  * v9fs_get_new_inode_from_fid - Helper routine to populate an inode by
209  * issuing a attribute request
210  * @v9ses: session information
211  * @fid: fid to issue attribute request for
212  * @sb: superblock on which to create inode
213  *
214  */
215 static inline struct inode *
216 v9fs_get_new_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
217 			    struct super_block *sb)
218 {
219 	if (v9fs_proto_dotl(v9ses))
220 		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 1);
221 	else
222 		return v9fs_inode_from_fid(v9ses, fid, sb, 1);
223 }
224 
225 #endif
226