xref: /openbmc/linux/fs/9p/v9fs.h (revision 3ddc8b84)
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 #include <linux/netfs.h>
13 
14 /**
15  * enum p9_session_flags - option flags for each 9P session
16  * @V9FS_PROTO_2000U: whether or not to use 9P2000.u extensions
17  * @V9FS_PROTO_2000L: whether or not to use 9P2000.l extensions
18  * @V9FS_ACCESS_SINGLE: only the mounting user can access the hierarchy
19  * @V9FS_ACCESS_USER: a new attach will be issued for every user (default)
20  * @V9FS_ACCESS_CLIENT: Just like user, but access check is performed on client.
21  * @V9FS_ACCESS_ANY: use a single attach for all users
22  * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
23  * @V9FS_POSIX_ACL: POSIX ACLs are enforced
24  *
25  * Session flags reflect options selected by users at mount time
26  */
27 #define	V9FS_ACCESS_ANY (V9FS_ACCESS_SINGLE | \
28 			 V9FS_ACCESS_USER |   \
29 			 V9FS_ACCESS_CLIENT)
30 #define V9FS_ACCESS_MASK V9FS_ACCESS_ANY
31 #define V9FS_ACL_MASK V9FS_POSIX_ACL
32 
33 enum p9_session_flags {
34 	V9FS_PROTO_2000U    = 0x01,
35 	V9FS_PROTO_2000L    = 0x02,
36 	V9FS_ACCESS_SINGLE  = 0x04,
37 	V9FS_ACCESS_USER    = 0x08,
38 	V9FS_ACCESS_CLIENT  = 0x10,
39 	V9FS_POSIX_ACL      = 0x20,
40 	V9FS_NO_XATTR       = 0x40,
41 	V9FS_IGNORE_QV      = 0x80, /* ignore qid.version for cache hints */
42 	V9FS_DIRECT_IO      = 0x100,
43 	V9FS_SYNC           = 0x200
44 };
45 
46 /**
47  * enum p9_cache_shortcuts - human readable cache preferences
48  * @CACHE_SC_NONE: disable all caches
49  * @CACHE_SC_READAHEAD: only provide caching for readahead
50  * @CACHE_SC_MMAP: provide caching to enable mmap
51  * @CACHE_SC_LOOSE: non-coherent caching for files and meta data
52  * @CACHE_SC_FSCACHE: persistent non-coherent caching for files and meta-data
53  *
54  */
55 
56 enum p9_cache_shortcuts {
57 	CACHE_SC_NONE       = 0b00000000,
58 	CACHE_SC_READAHEAD  = 0b00000001,
59 	CACHE_SC_MMAP       = 0b00000101,
60 	CACHE_SC_LOOSE      = 0b00001111,
61 	CACHE_SC_FSCACHE    = 0b10001111,
62 };
63 
64 /**
65  * enum p9_cache_bits - possible values of ->cache
66  * @CACHE_NONE: caches disabled
67  * @CACHE_FILE: file caching (open to close)
68  * @CACHE_META: meta-data and directory caching
69  * @CACHE_WRITEBACK: write-back caching for files
70  * @CACHE_LOOSE: don't check cache consistency
71  * @CACHE_FSCACHE: local persistent caches
72  *
73  */
74 
75 enum p9_cache_bits {
76 	CACHE_NONE          = 0b00000000,
77 	CACHE_FILE          = 0b00000001,
78 	CACHE_META          = 0b00000010,
79 	CACHE_WRITEBACK     = 0b00000100,
80 	CACHE_LOOSE         = 0b00001000,
81 	CACHE_FSCACHE       = 0b10000000,
82 };
83 
84 /**
85  * struct v9fs_session_info - per-instance session information
86  * @flags: session options of type &p9_session_flags
87  * @nodev: set to 1 to disable device mapping
88  * @debug: debug level
89  * @afid: authentication handle
90  * @cache: cache mode of type &p9_cache_bits
91  * @cachetag: the tag of the cache associated with this session
92  * @fscache: session cookie associated with FS-Cache
93  * @uname: string user name to mount hierarchy as
94  * @aname: mount specifier for remote hierarchy
95  * @maxdata: maximum data to be sent/recvd per protocol message
96  * @dfltuid: default numeric userid to mount hierarchy as
97  * @dfltgid: default numeric groupid to mount hierarchy as
98  * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
99  * @clnt: reference to 9P network client instantiated for this session
100  * @slist: reference to list of registered 9p sessions
101  *
102  * This structure holds state for each session instance established during
103  * a sys_mount() .
104  *
105  * Bugs: there seems to be a lot of state which could be condensed and/or
106  * removed.
107  */
108 
109 struct v9fs_session_info {
110 	/* options */
111 	unsigned int flags;
112 	unsigned char nodev;
113 	unsigned short debug;
114 	unsigned int afid;
115 	unsigned int cache;
116 #ifdef CONFIG_9P_FSCACHE
117 	char *cachetag;
118 	struct fscache_volume *fscache;
119 #endif
120 
121 	char *uname;		/* user name to mount as */
122 	char *aname;		/* name of remote hierarchy being mounted */
123 	unsigned int maxdata;	/* max data for client interface */
124 	kuid_t dfltuid;		/* default uid/muid for legacy support */
125 	kgid_t dfltgid;		/* default gid for legacy support */
126 	kuid_t uid;		/* if ACCESS_SINGLE, the uid that has access */
127 	struct p9_client *clnt;	/* 9p client */
128 	struct list_head slist; /* list of sessions registered with v9fs */
129 	struct rw_semaphore rename_sem;
130 	long session_lock_timeout; /* retry interval for blocking locks */
131 };
132 
133 /* cache_validity flags */
134 #define V9FS_INO_INVALID_ATTR 0x01
135 
136 struct v9fs_inode {
137 	struct netfs_inode netfs; /* Netfslib context and vfs inode */
138 	struct p9_qid qid;
139 	unsigned int cache_validity;
140 	struct mutex v_mutex;
141 };
142 
143 static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
144 {
145 	return container_of(inode, struct v9fs_inode, netfs.inode);
146 }
147 
148 static inline struct fscache_cookie *v9fs_inode_cookie(struct v9fs_inode *v9inode)
149 {
150 #ifdef CONFIG_9P_FSCACHE
151 	return netfs_i_cookie(&v9inode->netfs);
152 #else
153 	return NULL;
154 #endif
155 }
156 
157 static inline struct fscache_volume *v9fs_session_cache(struct v9fs_session_info *v9ses)
158 {
159 #ifdef CONFIG_9P_FSCACHE
160 	return v9ses->fscache;
161 #else
162 	return NULL;
163 #endif
164 }
165 
166 
167 extern int v9fs_show_options(struct seq_file *m, struct dentry *root);
168 
169 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
170 				 const char *dev_name, char *data);
171 extern void v9fs_session_close(struct v9fs_session_info *v9ses);
172 extern void v9fs_session_cancel(struct v9fs_session_info *v9ses);
173 extern void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
174 extern struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
175 				      unsigned int flags);
176 extern int v9fs_vfs_unlink(struct inode *i, struct dentry *d);
177 extern int v9fs_vfs_rmdir(struct inode *i, struct dentry *d);
178 extern int v9fs_vfs_rename(struct mnt_idmap *idmap,
179 			   struct inode *old_dir, struct dentry *old_dentry,
180 			   struct inode *new_dir, struct dentry *new_dentry,
181 			   unsigned int flags);
182 extern struct inode *v9fs_inode_from_fid(struct v9fs_session_info *v9ses,
183 					 struct p9_fid *fid,
184 					 struct super_block *sb, int new);
185 extern const struct inode_operations v9fs_dir_inode_operations_dotl;
186 extern const struct inode_operations v9fs_file_inode_operations_dotl;
187 extern const struct inode_operations v9fs_symlink_inode_operations_dotl;
188 extern const struct netfs_request_ops v9fs_req_ops;
189 extern struct inode *v9fs_inode_from_fid_dotl(struct v9fs_session_info *v9ses,
190 					      struct p9_fid *fid,
191 					      struct super_block *sb, int new);
192 
193 /* other default globals */
194 #define V9FS_PORT	564
195 #define V9FS_DEFUSER	"nobody"
196 #define V9FS_DEFANAME	""
197 #define V9FS_DEFUID	KUIDT_INIT(-2)
198 #define V9FS_DEFGID	KGIDT_INIT(-2)
199 
200 static inline struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
201 {
202 	return inode->i_sb->s_fs_info;
203 }
204 
205 static inline struct v9fs_session_info *v9fs_dentry2v9ses(struct dentry *dentry)
206 {
207 	return dentry->d_sb->s_fs_info;
208 }
209 
210 static inline int v9fs_proto_dotu(struct v9fs_session_info *v9ses)
211 {
212 	return v9ses->flags & V9FS_PROTO_2000U;
213 }
214 
215 static inline int v9fs_proto_dotl(struct v9fs_session_info *v9ses)
216 {
217 	return v9ses->flags & V9FS_PROTO_2000L;
218 }
219 
220 /**
221  * v9fs_get_inode_from_fid - Helper routine to populate an inode by
222  * issuing a attribute request
223  * @v9ses: session information
224  * @fid: fid to issue attribute request for
225  * @sb: superblock on which to create inode
226  *
227  */
228 static inline struct inode *
229 v9fs_get_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
230 			struct super_block *sb)
231 {
232 	if (v9fs_proto_dotl(v9ses))
233 		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 0);
234 	else
235 		return v9fs_inode_from_fid(v9ses, fid, sb, 0);
236 }
237 
238 /**
239  * v9fs_get_new_inode_from_fid - Helper routine to populate an inode by
240  * issuing a attribute request
241  * @v9ses: session information
242  * @fid: fid to issue attribute request for
243  * @sb: superblock on which to create inode
244  *
245  */
246 static inline struct inode *
247 v9fs_get_new_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
248 			    struct super_block *sb)
249 {
250 	if (v9fs_proto_dotl(v9ses))
251 		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 1);
252 	else
253 		return v9fs_inode_from_fid(v9ses, fid, sb, 1);
254 }
255 
256 #endif
257