1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * 9P Client Definitions
4 *
5 * Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
6 * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
7 */
8
9 #ifndef NET_9P_CLIENT_H
10 #define NET_9P_CLIENT_H
11
12 #include <linux/utsname.h>
13 #include <linux/idr.h>
14 #include <linux/tracepoint-defs.h>
15
16 /* Number of requests per row */
17 #define P9_ROW_MAXTAG 255
18
19 /** enum p9_proto_versions - 9P protocol versions
20 * @p9_proto_legacy: 9P Legacy mode, pre-9P2000.u
21 * @p9_proto_2000u: 9P2000.u extension
22 * @p9_proto_2000L: 9P2000.L extension
23 */
24
25 enum p9_proto_versions {
26 p9_proto_legacy,
27 p9_proto_2000u,
28 p9_proto_2000L,
29 };
30
31
32 /**
33 * enum p9_trans_status - different states of underlying transports
34 * @Connected: transport is connected and healthy
35 * @Disconnected: transport has been disconnected
36 * @Hung: transport is connected by wedged
37 *
38 * This enumeration details the various states a transport
39 * instatiation can be in.
40 */
41
42 enum p9_trans_status {
43 Connected,
44 BeginDisconnect,
45 Disconnected,
46 Hung,
47 };
48
49 /**
50 * enum p9_req_status_t - status of a request
51 * @REQ_STATUS_ALLOC: request has been allocated but not sent
52 * @REQ_STATUS_UNSENT: request waiting to be sent
53 * @REQ_STATUS_SENT: request sent to server
54 * @REQ_STATUS_RCVD: response received from server
55 * @REQ_STATUS_FLSHD: request has been flushed
56 * @REQ_STATUS_ERROR: request encountered an error on the client side
57 */
58
59 enum p9_req_status_t {
60 REQ_STATUS_ALLOC,
61 REQ_STATUS_UNSENT,
62 REQ_STATUS_SENT,
63 REQ_STATUS_RCVD,
64 REQ_STATUS_FLSHD,
65 REQ_STATUS_ERROR,
66 };
67
68 /**
69 * struct p9_req_t - request slots
70 * @status: status of this request slot
71 * @t_err: transport error
72 * @wq: wait_queue for the client to block on for this request
73 * @tc: the request fcall structure
74 * @rc: the response fcall structure
75 * @req_list: link for higher level objects to chain requests
76 */
77 struct p9_req_t {
78 int status;
79 int t_err;
80 refcount_t refcount;
81 wait_queue_head_t wq;
82 struct p9_fcall tc;
83 struct p9_fcall rc;
84 struct list_head req_list;
85 };
86
87 /**
88 * struct p9_client - per client instance state
89 * @lock: protect @fids and @reqs
90 * @msize: maximum data size negotiated by protocol
91 * @proto_version: 9P protocol version to use
92 * @trans_mod: module API instantiated with this client
93 * @status: connection state
94 * @trans: tranport instance state and API
95 * @fids: All active FID handles
96 * @reqs: All active requests.
97 * @name: node name used as client id
98 *
99 * The client structure is used to keep track of various per-client
100 * state that has been instantiated.
101 */
102 struct p9_client {
103 spinlock_t lock;
104 unsigned int msize;
105 unsigned char proto_version;
106 struct p9_trans_module *trans_mod;
107 enum p9_trans_status status;
108 void *trans;
109 struct kmem_cache *fcall_cache;
110
111 union {
112 struct {
113 int rfd;
114 int wfd;
115 } fd;
116 struct {
117 u16 port;
118 bool privport;
119
120 } tcp;
121 } trans_opts;
122
123 struct idr fids;
124 struct idr reqs;
125
126 char name[__NEW_UTS_LEN + 1];
127 };
128
129 /**
130 * struct p9_fid - file system entity handle
131 * @clnt: back pointer to instantiating &p9_client
132 * @fid: numeric identifier for this handle
133 * @mode: current mode of this fid (enum?)
134 * @qid: the &p9_qid server identifier this handle points to
135 * @iounit: the server reported maximum transaction size for this file
136 * @uid: the numeric uid of the local user who owns this handle
137 * @rdir: readdir accounting structure (allocated on demand)
138 * @dlist: per-dentry fid tracking
139 *
140 * TODO: This needs lots of explanation.
141 */
142 enum fid_source {
143 FID_FROM_OTHER,
144 FID_FROM_INODE,
145 FID_FROM_DENTRY,
146 };
147
148 struct p9_fid {
149 struct p9_client *clnt;
150 u32 fid;
151 refcount_t count;
152 int mode;
153 struct p9_qid qid;
154 u32 iounit;
155 kuid_t uid;
156
157 void *rdir;
158
159 struct hlist_node dlist; /* list of all fids attached to a dentry */
160 struct hlist_node ilist;
161 };
162
163 /**
164 * struct p9_dirent - directory entry structure
165 * @qid: The p9 server qid for this dirent
166 * @d_off: offset to the next dirent
167 * @d_type: type of file
168 * @d_name: file name
169 */
170
171 struct p9_dirent {
172 struct p9_qid qid;
173 u64 d_off;
174 unsigned char d_type;
175 char d_name[256];
176 };
177
178 struct iov_iter;
179
180 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt);
181 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb);
182 int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid,
183 const char *name);
184 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
185 struct p9_fid *newdirfid, const char *new_name);
186 struct p9_client *p9_client_create(const char *dev_name, char *options);
187 void p9_client_destroy(struct p9_client *clnt);
188 void p9_client_disconnect(struct p9_client *clnt);
189 void p9_client_begin_disconnect(struct p9_client *clnt);
190 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
191 const char *uname, kuid_t n_uname, const char *aname);
192 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
193 const unsigned char * const *wnames, int clone);
194 int p9_client_open(struct p9_fid *fid, int mode);
195 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
196 char *extension);
197 int p9_client_link(struct p9_fid *fid, struct p9_fid *oldfid, const char *newname);
198 int p9_client_symlink(struct p9_fid *fid, const char *name, const char *symname,
199 kgid_t gid, struct p9_qid *qid);
200 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
201 kgid_t gid, struct p9_qid *qid);
202 int p9_client_clunk(struct p9_fid *fid);
203 int p9_client_fsync(struct p9_fid *fid, int datasync);
204 int p9_client_remove(struct p9_fid *fid);
205 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags);
206 int p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err);
207 int p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
208 int *err);
209 int p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err);
210 struct netfs_io_subrequest;
211 void p9_client_write_subreq(struct netfs_io_subrequest *subreq);
212 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
213 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
214 struct p9_dirent *dirent);
215 struct p9_wstat *p9_client_stat(struct p9_fid *fid);
216 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
217 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
218
219 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
220 u64 request_mask);
221
222 int p9_client_mknod_dotl(struct p9_fid *oldfid, const char *name, int mode,
223 dev_t rdev, kgid_t gid, struct p9_qid *qid);
224 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
225 kgid_t gid, struct p9_qid *qid);
226 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
227 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
228 void p9_fcall_fini(struct p9_fcall *fc);
229 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag);
230
231 static inline void p9_req_get(struct p9_req_t *r)
232 {
233 refcount_inc(&r->refcount);
234 }
235
236 static inline int p9_req_try_get(struct p9_req_t *r)
237 {
238 return refcount_inc_not_zero(&r->refcount);
239 }
240
241 int p9_req_put(struct p9_client *c, struct p9_req_t *r);
242
243 /* We cannot have the real tracepoints in header files,
244 * use a wrapper function */
245 DECLARE_TRACEPOINT(9p_fid_ref);
246 void do_trace_9p_fid_get(struct p9_fid *fid);
247 void do_trace_9p_fid_put(struct p9_fid *fid);
248
249 /* fid reference counting helpers:
250 * - fids used for any length of time should always be referenced through
251 * p9_fid_get(), and released with p9_fid_put()
252 * - v9fs_fid_lookup() or similar will automatically call get for you
253 * and also require a put
254 * - the *_fid_add() helpers will stash the fid in the inode,
255 * at which point it is the responsibility of evict_inode()
256 * to call the put
257 * - the last put will automatically send a clunk to the server
258 */
259 static inline struct p9_fid *p9_fid_get(struct p9_fid *fid)
260 {
261 if (tracepoint_enabled(9p_fid_ref))
262 do_trace_9p_fid_get(fid);
263
264 refcount_inc(&fid->count);
265
266 return fid;
267 }
268
269 static inline int p9_fid_put(struct p9_fid *fid)
270 {
271 if (!fid || IS_ERR(fid))
272 return 0;
273
274 if (tracepoint_enabled(9p_fid_ref))
275 do_trace_9p_fid_put(fid);
276
277 if (!refcount_dec_and_test(&fid->count))
278 return 0;
279
280 return p9_client_clunk(fid);
281 }
282
283 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
284
285 int p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
286 int16_t *tag, int rewind);
287 int p9stat_read(struct p9_client *clnt, char *buf, int len,
288 struct p9_wstat *st);
289 void p9stat_free(struct p9_wstat *stbuf);
290
291 int p9_is_proto_dotu(struct p9_client *clnt);
292 int p9_is_proto_dotl(struct p9_client *clnt);
293 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
294 const char *attr_name, u64 *attr_size);
295 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
296 u64 attr_size, int flags);
297 int p9_client_readlink(struct p9_fid *fid, char **target);
298
299 int p9_client_init(void);
300 void p9_client_exit(void);
301
302 #endif /* NET_9P_CLIENT_H */
303
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