1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * V9FS definitions.
4  *
5  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
6  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
7  */
8 #ifndef FS_9P_V9FS_H
9 #define FS_9P_V9FS_H
10 
11 #include <linux/backing-dev.h>
12 
13 /**
14  * enum p9_session_flags - option flags for each 9P session
15  * @V9FS_PROTO_2000U: whether or not to use 9P2000.u extensions
16  * @V9FS_PROTO_2000L: whether or not to use 9P2000.l extensions
17  * @V9FS_ACCESS_SINGLE: only the mounting user can access the hierarchy
18  * @V9FS_ACCESS_USER: a new attach will be issued for every user (default)
19  * @V9FS_ACCESS_CLIENT: Just like user, but access check is performed on client.
20  * @V9FS_ACCESS_ANY: use a single attach for all users
21  * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
22  * @V9FS_POSIX_ACL: POSIX ACLs are enforced
23  *
24  * Session flags reflect options selected by users at mount time
25  */
26 #define	V9FS_ACCESS_ANY (V9FS_ACCESS_SINGLE | \
27 			 V9FS_ACCESS_USER |   \
28 			 V9FS_ACCESS_CLIENT)
29 #define V9FS_ACCESS_MASK V9FS_ACCESS_ANY
30 #define V9FS_ACL_MASK V9FS_POSIX_ACL
31 
32 enum p9_session_flags {
33 	V9FS_PROTO_2000U	= 0x01,
34 	V9FS_PROTO_2000L	= 0x02,
35 	V9FS_ACCESS_SINGLE	= 0x04,
36 	V9FS_ACCESS_USER	= 0x08,
37 	V9FS_ACCESS_CLIENT	= 0x10,
38 	V9FS_POSIX_ACL		= 0x20
39 };
40 
41 /* possible values of ->cache */
42 /**
43  * enum p9_cache_modes - user specified cache preferences
44  * @CACHE_NONE: do not cache data, dentries, or directory contents (default)
45  * @CACHE_LOOSE: cache data, dentries, and directory contents w/no consistency
46  *
47  * eventually support loose, tight, time, session, default always none
48  */
49 
50 enum p9_cache_modes {
51 	CACHE_NONE,
52 	CACHE_MMAP,
53 	CACHE_LOOSE,
54 	CACHE_FSCACHE,
55 	nr__p9_cache_modes
56 };
57 
58 /**
59  * struct v9fs_session_info - per-instance session information
60  * @flags: session options of type &p9_session_flags
61  * @nodev: set to 1 to disable device mapping
62  * @debug: debug level
63  * @afid: authentication handle
64  * @cache: cache mode of type &p9_cache_modes
65  * @cachetag: the tag of the cache associated with this session
66  * @fscache: session cookie associated with FS-Cache
67  * @uname: string user name to mount hierarchy as
68  * @aname: mount specifier for remote hierarchy
69  * @maxdata: maximum data to be sent/recvd per protocol message
70  * @dfltuid: default numeric userid to mount hierarchy as
71  * @dfltgid: default numeric groupid to mount hierarchy as
72  * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
73  * @clnt: reference to 9P network client instantiated for this session
74  * @slist: reference to list of registered 9p sessions
75  *
76  * This structure holds state for each session instance established during
77  * a sys_mount() .
78  *
79  * Bugs: there seems to be a lot of state which could be condensed and/or
80  * removed.
81  */
82 
83 struct v9fs_session_info {
84 	/* options */
85 	unsigned char flags;
86 	unsigned char nodev;
87 	unsigned short debug;
88 	unsigned int afid;
89 	unsigned int cache;
90 #ifdef CONFIG_9P_FSCACHE
91 	char *cachetag;
92 	struct fscache_cookie *fscache;
93 #endif
94 
95 	char *uname;		/* user name to mount as */
96 	char *aname;		/* name of remote hierarchy being mounted */
97 	unsigned int maxdata;	/* max data for client interface */
98 	kuid_t dfltuid;		/* default uid/muid for legacy support */
99 	kgid_t dfltgid;		/* default gid for legacy support */
100 	kuid_t uid;		/* if ACCESS_SINGLE, the uid that has access */
101 	struct p9_client *clnt;	/* 9p client */
102 	struct list_head slist; /* list of sessions registered with v9fs */
103 	struct rw_semaphore rename_sem;
104 	long session_lock_timeout; /* retry interval for blocking locks */
105 };
106 
107 /* cache_validity flags */
108 #define V9FS_INO_INVALID_ATTR 0x01
109 
110 struct v9fs_inode {
111 #ifdef CONFIG_9P_FSCACHE
112 	struct mutex fscache_lock;
113 	struct fscache_cookie *fscache;
114 #endif
115 	struct p9_qid qid;
116 	unsigned int cache_validity;
117 	struct p9_fid *writeback_fid;
118 	struct mutex v_mutex;
119 	struct inode vfs_inode;
120 };
121 
V9FS_I(const struct inode * inode)122 static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
123 {
124 	return container_of(inode, struct v9fs_inode, vfs_inode);
125 }
126 
v9fs_inode_cookie(struct v9fs_inode * v9inode)127 static inline struct fscache_cookie *v9fs_inode_cookie(struct v9fs_inode *v9inode)
128 {
129 #ifdef CONFIG_9P_FSCACHE
130 	return v9inode->fscache;
131 #else
132 	return NULL;
133 #endif
134 }
135 
136 extern int v9fs_show_options(struct seq_file *m, struct dentry *root);
137 
138 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
139 				 const char *dev_name, char *data);
140 extern void v9fs_session_close(struct v9fs_session_info *v9ses);
141 extern void v9fs_session_cancel(struct v9fs_session_info *v9ses);
142 extern void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
143 extern struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
144 				      unsigned int flags);
145 extern int v9fs_vfs_unlink(struct inode *i, struct dentry *d);
146 extern int v9fs_vfs_rmdir(struct inode *i, struct dentry *d);
147 extern int v9fs_vfs_rename(struct user_namespace *mnt_userns,
148 			   struct inode *old_dir, struct dentry *old_dentry,
149 			   struct inode *new_dir, struct dentry *new_dentry,
150 			   unsigned int flags);
151 extern struct inode *v9fs_inode_from_fid(struct v9fs_session_info *v9ses,
152 					 struct p9_fid *fid,
153 					 struct super_block *sb, int new);
154 extern const struct inode_operations v9fs_dir_inode_operations_dotl;
155 extern const struct inode_operations v9fs_file_inode_operations_dotl;
156 extern const struct inode_operations v9fs_symlink_inode_operations_dotl;
157 extern struct inode *v9fs_inode_from_fid_dotl(struct v9fs_session_info *v9ses,
158 					      struct p9_fid *fid,
159 					      struct super_block *sb, int new);
160 
161 /* other default globals */
162 #define V9FS_PORT	564
163 #define V9FS_DEFUSER	"nobody"
164 #define V9FS_DEFANAME	""
165 #define V9FS_DEFUID	KUIDT_INIT(-2)
166 #define V9FS_DEFGID	KGIDT_INIT(-2)
167 
v9fs_inode2v9ses(struct inode * inode)168 static inline struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
169 {
170 	return inode->i_sb->s_fs_info;
171 }
172 
v9fs_dentry2v9ses(struct dentry * dentry)173 static inline struct v9fs_session_info *v9fs_dentry2v9ses(struct dentry *dentry)
174 {
175 	return dentry->d_sb->s_fs_info;
176 }
177 
v9fs_proto_dotu(struct v9fs_session_info * v9ses)178 static inline int v9fs_proto_dotu(struct v9fs_session_info *v9ses)
179 {
180 	return v9ses->flags & V9FS_PROTO_2000U;
181 }
182 
v9fs_proto_dotl(struct v9fs_session_info * v9ses)183 static inline int v9fs_proto_dotl(struct v9fs_session_info *v9ses)
184 {
185 	return v9ses->flags & V9FS_PROTO_2000L;
186 }
187 
188 /**
189  * v9fs_get_inode_from_fid - Helper routine to populate an inode by
190  * issuing a attribute request
191  * @v9ses: session information
192  * @fid: fid to issue attribute request for
193  * @sb: superblock on which to create inode
194  *
195  */
196 static inline struct inode *
v9fs_get_inode_from_fid(struct v9fs_session_info * v9ses,struct p9_fid * fid,struct super_block * sb)197 v9fs_get_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
198 			struct super_block *sb)
199 {
200 	if (v9fs_proto_dotl(v9ses))
201 		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 0);
202 	else
203 		return v9fs_inode_from_fid(v9ses, fid, sb, 0);
204 }
205 
206 /**
207  * v9fs_get_new_inode_from_fid - Helper routine to populate an inode by
208  * issuing a attribute request
209  * @v9ses: session information
210  * @fid: fid to issue attribute request for
211  * @sb: superblock on which to create inode
212  *
213  */
214 static inline struct inode *
v9fs_get_new_inode_from_fid(struct v9fs_session_info * v9ses,struct p9_fid * fid,struct super_block * sb)215 v9fs_get_new_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
216 			    struct super_block *sb)
217 {
218 	if (v9fs_proto_dotl(v9ses))
219 		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 1);
220 	else
221 		return v9fs_inode_from_fid(v9ses, fid, sb, 1);
222 }
223 
224 #endif
225