519b21d8b15b69e4593ee9782a4a1821cc2974a9
[linux-2.6.git] / fs / 9p / v9fs.c
1 /*
2  *  linux/fs/9p/v9fs.c
3  *
4  *  This file contains functions assisting in mapping VFS to 9P2000
5  *
6  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License as published by
11  *  the Free Software Foundation; either version 2 of the License, or
12  *  (at your option) any later version.
13  *
14  *  This program is distributed in the hope that it will be useful,
15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  *  GNU General Public License for more details.
18  *
19  *  You should have received a copy of the GNU General Public License
20  *  along with this program; if not, write to:
21  *  Free Software Foundation
22  *  51 Franklin Street, Fifth Floor
23  *  Boston, MA  02111-1301  USA
24  *
25  */
26
27 #include <linux/config.h>
28 #include <linux/module.h>
29 #include <linux/errno.h>
30 #include <linux/fs.h>
31 #include <linux/parser.h>
32 #include <linux/idr.h>
33
34 #include "debug.h"
35 #include "v9fs.h"
36 #include "9p.h"
37 #include "v9fs_vfs.h"
38 #include "transport.h"
39 #include "mux.h"
40
41 /* TODO: sysfs or debugfs interface */
42 int v9fs_debug_level = 0;       /* feature-rific global debug level  */
43
44 /*
45   * Option Parsing (code inspired by NFS code)
46   *
47   */
48
49 enum {
50         /* Options that take integer arguments */
51         Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid, Opt_debug,
52         Opt_rfdno, Opt_wfdno,
53         /* String options */
54         Opt_name, Opt_remotename,
55         /* Options that take no arguments */
56         Opt_legacy, Opt_nodevmap, Opt_unix, Opt_tcp, Opt_fd,
57         /* Error token */
58         Opt_err
59 };
60
61 static match_table_t tokens = {
62         {Opt_port, "port=%u"},
63         {Opt_msize, "msize=%u"},
64         {Opt_uid, "uid=%u"},
65         {Opt_gid, "gid=%u"},
66         {Opt_afid, "afid=%u"},
67         {Opt_rfdno, "rfdno=%u"},
68         {Opt_wfdno, "wfdno=%u"},
69         {Opt_debug, "debug=%u"},
70         {Opt_name, "name=%s"},
71         {Opt_remotename, "aname=%s"},
72         {Opt_unix, "proto=unix"},
73         {Opt_tcp, "proto=tcp"},
74         {Opt_fd, "proto=fd"},
75         {Opt_tcp, "tcp"},
76         {Opt_unix, "unix"},
77         {Opt_fd, "fd"},
78         {Opt_legacy, "noextend"},
79         {Opt_nodevmap, "nodevmap"},
80         {Opt_err, NULL}
81 };
82
83 /*
84  *  Parse option string.
85  */
86
87 /**
88  * v9fs_parse_options - parse mount options into session structure
89  * @options: options string passed from mount
90  * @v9ses: existing v9fs session information
91  *
92  */
93
94 static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
95 {
96         char *p;
97         substring_t args[MAX_OPT_ARGS];
98         int option;
99         int ret;
100
101         /* setup defaults */
102         v9ses->port = V9FS_PORT;
103         v9ses->maxdata = 9000;
104         v9ses->proto = PROTO_TCP;
105         v9ses->extended = 1;
106         v9ses->afid = ~0;
107         v9ses->debug = 0;
108         v9ses->rfdno = ~0;
109         v9ses->wfdno = ~0;
110
111         if (!options)
112                 return;
113
114         while ((p = strsep(&options, ",")) != NULL) {
115                 int token;
116                 if (!*p)
117                         continue;
118                 token = match_token(p, tokens, args);
119                 if (token < Opt_name) {
120                         if ((ret = match_int(&args[0], &option)) < 0) {
121                                 dprintk(DEBUG_ERROR,
122                                         "integer field, but no integer?\n");
123                                 continue;
124                         }
125
126                 }
127                 switch (token) {
128                 case Opt_port:
129                         v9ses->port = option;
130                         break;
131                 case Opt_msize:
132                         v9ses->maxdata = option;
133                         break;
134                 case Opt_uid:
135                         v9ses->uid = option;
136                         break;
137                 case Opt_gid:
138                         v9ses->gid = option;
139                         break;
140                 case Opt_afid:
141                         v9ses->afid = option;
142                         break;
143                 case Opt_rfdno:
144                         v9ses->rfdno = option;
145                         break;
146                 case Opt_wfdno:
147                         v9ses->wfdno = option;
148                         break;
149                 case Opt_debug:
150                         v9ses->debug = option;
151                         break;
152                 case Opt_tcp:
153                         v9ses->proto = PROTO_TCP;
154                         break;
155                 case Opt_unix:
156                         v9ses->proto = PROTO_UNIX;
157                         break;
158                 case Opt_fd:
159                         v9ses->proto = PROTO_FD;
160                         break;
161                 case Opt_name:
162                         match_strcpy(v9ses->name, &args[0]);
163                         break;
164                 case Opt_remotename:
165                         match_strcpy(v9ses->remotename, &args[0]);
166                         break;
167                 case Opt_legacy:
168                         v9ses->extended = 0;
169                         break;
170                 case Opt_nodevmap:
171                         v9ses->nodev = 1;
172                         break;
173                 default:
174                         continue;
175                 }
176         }
177 }
178
179 /**
180  * v9fs_inode2v9ses - safely extract v9fs session info from super block
181  * @inode: inode to extract information from
182  *
183  * Paranoid function to extract v9ses information from superblock,
184  * if anything is missing it will report an error.
185  *
186  */
187
188 struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
189 {
190         return (inode->i_sb->s_fs_info);
191 }
192
193 /**
194  * v9fs_get_idpool - allocate numeric id from pool
195  * @p - pool to allocate from
196  *
197  * XXX - This seems to be an awful generic function, should it be in idr.c with
198  *            the lock included in struct idr?
199  */
200
201 int v9fs_get_idpool(struct v9fs_idpool *p)
202 {
203         int i = 0;
204         int error;
205
206 retry:
207         if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
208                 return 0;
209
210         if (down_interruptible(&p->lock) == -EINTR) {
211                 eprintk(KERN_WARNING, "Interrupted while locking\n");
212                 return -1;
213         }
214
215         /* no need to store exactly p, we just need something non-null */
216         error = idr_get_new(&p->pool, p, &i);
217         up(&p->lock);
218
219         if (error == -EAGAIN)
220                 goto retry;
221         else if (error)
222                 return -1;
223
224         return i;
225 }
226
227 /**
228  * v9fs_put_idpool - release numeric id from pool
229  * @p - pool to allocate from
230  *
231  * XXX - This seems to be an awful generic function, should it be in idr.c with
232  *            the lock included in struct idr?
233  */
234
235 void v9fs_put_idpool(int id, struct v9fs_idpool *p)
236 {
237         if (down_interruptible(&p->lock) == -EINTR) {
238                 eprintk(KERN_WARNING, "Interrupted while locking\n");
239                 return;
240         }
241         idr_remove(&p->pool, id);
242         up(&p->lock);
243 }
244
245 /**
246  * v9fs_check_idpool - check if the specified id is available
247  * @id - id to check
248  * @p - pool
249  */
250 int v9fs_check_idpool(int id, struct v9fs_idpool *p)
251 {
252         return idr_find(&p->pool, id) != NULL;
253 }
254
255 /**
256  * v9fs_session_init - initialize session
257  * @v9ses: session information structure
258  * @dev_name: device being mounted
259  * @data: options
260  *
261  */
262
263 int
264 v9fs_session_init(struct v9fs_session_info *v9ses,
265                   const char *dev_name, char *data)
266 {
267         struct v9fs_fcall *fcall = NULL;
268         struct v9fs_transport *trans_proto;
269         int n = 0;
270         int newfid = -1;
271         int retval = -EINVAL;
272
273         v9ses->name = __getname();
274         if (!v9ses->name)
275                 return -ENOMEM;
276
277         v9ses->remotename = __getname();
278         if (!v9ses->remotename) {
279                 __putname(v9ses->name);
280                 return -ENOMEM;
281         }
282
283         strcpy(v9ses->name, V9FS_DEFUSER);
284         strcpy(v9ses->remotename, V9FS_DEFANAME);
285
286         v9fs_parse_options(data, v9ses);
287
288         /* set global debug level */
289         v9fs_debug_level = v9ses->debug;
290
291         /* id pools that are session-dependent: FIDs and TIDs */
292         idr_init(&v9ses->fidpool.pool);
293         init_MUTEX(&v9ses->fidpool.lock);
294
295         switch (v9ses->proto) {
296         case PROTO_TCP:
297                 trans_proto = &v9fs_trans_tcp;
298                 break;
299         case PROTO_UNIX:
300                 trans_proto = &v9fs_trans_unix;
301                 *v9ses->remotename = 0;
302                 break;
303         case PROTO_FD:
304                 trans_proto = &v9fs_trans_fd;
305                 *v9ses->remotename = 0;
306                 break;
307         default:
308                 printk(KERN_ERR "v9fs: Bad mount protocol %d\n", v9ses->proto);
309                 retval = -ENOPROTOOPT;
310                 goto SessCleanUp;
311         };
312
313         v9ses->transport = kmalloc(sizeof(*v9ses->transport), GFP_KERNEL);
314         if (!v9ses->transport) {
315                 retval = -ENOMEM;
316                 goto SessCleanUp;
317         }
318
319         memmove(v9ses->transport, trans_proto, sizeof(*v9ses->transport));
320
321         if ((retval = v9ses->transport->init(v9ses, dev_name, data)) < 0) {
322                 eprintk(KERN_ERR, "problem initializing transport\n");
323                 goto SessCleanUp;
324         }
325
326         v9ses->inprogress = 0;
327         v9ses->shutdown = 0;
328         v9ses->session_hung = 0;
329
330         v9ses->mux = v9fs_mux_init(v9ses->transport, v9ses->maxdata + V9FS_IOHDRSZ,
331                 &v9ses->extended);
332
333         if (IS_ERR(v9ses->mux)) {
334                 retval = PTR_ERR(v9ses->mux);
335                 v9ses->mux = NULL;
336                 dprintk(DEBUG_ERROR, "problem initializing mux\n");
337                 goto SessCleanUp;
338         }
339
340         if (v9ses->afid == ~0) {
341                 if (v9ses->extended)
342                         retval =
343                             v9fs_t_version(v9ses, v9ses->maxdata, "9P2000.u",
344                                            &fcall);
345                 else
346                         retval = v9fs_t_version(v9ses, v9ses->maxdata, "9P2000",
347                                                 &fcall);
348
349                 if (retval < 0) {
350                         dprintk(DEBUG_ERROR, "v9fs_t_version failed\n");
351                         goto FreeFcall;
352                 }
353
354                 /* Really should check for 9P1 and report error */
355                 if (!v9fs_str_compare("9P2000.u", &fcall->params.rversion.version)) {
356                         dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
357                         v9ses->extended = 1;
358                 } else {
359                         dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
360                         v9ses->extended = 0;
361                 }
362
363                 n = fcall->params.rversion.msize;
364                 kfree(fcall);
365
366                 if (n < v9ses->maxdata)
367                         v9ses->maxdata = n;
368         }
369
370         newfid = v9fs_get_idpool(&v9ses->fidpool);
371         if (newfid < 0) {
372                 eprintk(KERN_WARNING, "couldn't allocate FID\n");
373                 retval = -ENOMEM;
374                 goto SessCleanUp;
375         }
376         /* it is a little bit ugly, but we have to prevent newfid */
377         /* being the same as afid, so if it is, get a new fid     */
378         if (v9ses->afid != ~0 && newfid == v9ses->afid) {
379                 newfid = v9fs_get_idpool(&v9ses->fidpool);
380                 if (newfid < 0) {
381                         eprintk(KERN_WARNING, "couldn't allocate FID\n");
382                         retval = -ENOMEM;
383                         goto SessCleanUp;
384                 }
385         }
386
387         if ((retval =
388              v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
389                            v9ses->afid, NULL))
390             < 0) {
391                 dprintk(DEBUG_ERROR, "cannot attach\n");
392                 goto SessCleanUp;
393         }
394
395         if (v9ses->afid != ~0) {
396                 if (v9fs_t_clunk(v9ses, v9ses->afid))
397                         dprintk(DEBUG_ERROR, "clunk failed\n");
398         }
399
400         return newfid;
401
402       FreeFcall:
403         kfree(fcall);
404
405       SessCleanUp:
406         v9fs_session_close(v9ses);
407         return retval;
408 }
409
410 /**
411  * v9fs_session_close - shutdown a session
412  * @v9ses: session information structure
413  *
414  */
415
416 void v9fs_session_close(struct v9fs_session_info *v9ses)
417 {
418         if (v9ses->mux) {
419                 v9fs_mux_destroy(v9ses->mux);
420                 v9ses->mux = NULL;
421         }
422
423         if (v9ses->transport) {
424                 v9ses->transport->close(v9ses->transport);
425                 kfree(v9ses->transport);
426                 v9ses->transport = NULL;
427         }
428
429         __putname(v9ses->name);
430         __putname(v9ses->remotename);
431 }
432
433 /**
434  * v9fs_session_cancel - mark transport as disconnected
435  *      and cancel all pending requests.
436  */
437 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
438         dprintk(DEBUG_ERROR, "cancel session %p\n", v9ses);
439         v9ses->transport->status = Disconnected;
440         v9fs_mux_cancel(v9ses->mux, -EIO);
441 }
442
443 extern int v9fs_error_init(void);
444
445 /**
446  * v9fs_init - Initialize module
447  *
448  */
449
450 static int __init init_v9fs(void)
451 {
452         v9fs_error_init();
453
454         printk(KERN_INFO "Installing v9fs 9P2000 file system support\n");
455
456         v9fs_mux_global_init();
457         return register_filesystem(&v9fs_fs_type);
458 }
459
460 /**
461  * v9fs_init - shutdown module
462  *
463  */
464
465 static void __exit exit_v9fs(void)
466 {
467         v9fs_mux_global_exit();
468         unregister_filesystem(&v9fs_fs_type);
469 }
470
471 module_init(init_v9fs)
472 module_exit(exit_v9fs)
473
474 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
475 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
476 MODULE_LICENSE("GPL");