Merge master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / 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 #include "conv.h"
41
42 /* TODO: sysfs or debugfs interface */
43 int v9fs_debug_level = 0;       /* feature-rific global debug level  */
44
45 /*
46   * Option Parsing (code inspired by NFS code)
47   *
48   */
49
50 enum {
51         /* Options that take integer arguments */
52         Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid, Opt_debug,
53         Opt_rfdno, Opt_wfdno,
54         /* String options */
55         Opt_name, Opt_remotename,
56         /* Options that take no arguments */
57         Opt_legacy, Opt_nodevmap, Opt_unix, Opt_tcp, Opt_fd,
58         /* Error token */
59         Opt_err
60 };
61
62 static match_table_t tokens = {
63         {Opt_port, "port=%u"},
64         {Opt_msize, "msize=%u"},
65         {Opt_uid, "uid=%u"},
66         {Opt_gid, "gid=%u"},
67         {Opt_afid, "afid=%u"},
68         {Opt_rfdno, "rfdno=%u"},
69         {Opt_wfdno, "wfdno=%u"},
70         {Opt_debug, "debug=%u"},
71         {Opt_name, "name=%s"},
72         {Opt_remotename, "aname=%s"},
73         {Opt_unix, "proto=unix"},
74         {Opt_tcp, "proto=tcp"},
75         {Opt_fd, "proto=fd"},
76         {Opt_tcp, "tcp"},
77         {Opt_unix, "unix"},
78         {Opt_fd, "fd"},
79         {Opt_legacy, "noextend"},
80         {Opt_nodevmap, "nodevmap"},
81         {Opt_err, NULL}
82 };
83
84 /*
85  *  Parse option string.
86  */
87
88 /**
89  * v9fs_parse_options - parse mount options into session structure
90  * @options: options string passed from mount
91  * @v9ses: existing v9fs session information
92  *
93  */
94
95 static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
96 {
97         char *p;
98         substring_t args[MAX_OPT_ARGS];
99         int option;
100         int ret;
101
102         /* setup defaults */
103         v9ses->port = V9FS_PORT;
104         v9ses->maxdata = 9000;
105         v9ses->proto = PROTO_TCP;
106         v9ses->extended = 1;
107         v9ses->afid = ~0;
108         v9ses->debug = 0;
109         v9ses->rfdno = ~0;
110         v9ses->wfdno = ~0;
111
112         if (!options)
113                 return;
114
115         while ((p = strsep(&options, ",")) != NULL) {
116                 int token;
117                 if (!*p)
118                         continue;
119                 token = match_token(p, tokens, args);
120                 if (token < Opt_name) {
121                         if ((ret = match_int(&args[0], &option)) < 0) {
122                                 dprintk(DEBUG_ERROR,
123                                         "integer field, but no integer?\n");
124                                 continue;
125                         }
126
127                 }
128                 switch (token) {
129                 case Opt_port:
130                         v9ses->port = option;
131                         break;
132                 case Opt_msize:
133                         v9ses->maxdata = option;
134                         break;
135                 case Opt_uid:
136                         v9ses->uid = option;
137                         break;
138                 case Opt_gid:
139                         v9ses->gid = option;
140                         break;
141                 case Opt_afid:
142                         v9ses->afid = option;
143                         break;
144                 case Opt_rfdno:
145                         v9ses->rfdno = option;
146                         break;
147                 case Opt_wfdno:
148                         v9ses->wfdno = option;
149                         break;
150                 case Opt_debug:
151                         v9ses->debug = option;
152                         break;
153                 case Opt_tcp:
154                         v9ses->proto = PROTO_TCP;
155                         break;
156                 case Opt_unix:
157                         v9ses->proto = PROTO_UNIX;
158                         break;
159                 case Opt_fd:
160                         v9ses->proto = PROTO_FD;
161                         break;
162                 case Opt_name:
163                         match_strcpy(v9ses->name, &args[0]);
164                         break;
165                 case Opt_remotename:
166                         match_strcpy(v9ses->remotename, &args[0]);
167                         break;
168                 case Opt_legacy:
169                         v9ses->extended = 0;
170                         break;
171                 case Opt_nodevmap:
172                         v9ses->nodev = 1;
173                         break;
174                 default:
175                         continue;
176                 }
177         }
178 }
179
180 /**
181  * v9fs_inode2v9ses - safely extract v9fs session info from super block
182  * @inode: inode to extract information from
183  *
184  * Paranoid function to extract v9ses information from superblock,
185  * if anything is missing it will report an error.
186  *
187  */
188
189 struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
190 {
191         return (inode->i_sb->s_fs_info);
192 }
193
194 /**
195  * v9fs_get_idpool - allocate numeric id from pool
196  * @p - pool to allocate from
197  *
198  * XXX - This seems to be an awful generic function, should it be in idr.c with
199  *            the lock included in struct idr?
200  */
201
202 int v9fs_get_idpool(struct v9fs_idpool *p)
203 {
204         int i = 0;
205         int error;
206
207 retry:
208         if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
209                 return 0;
210
211         if (down_interruptible(&p->lock) == -EINTR) {
212                 eprintk(KERN_WARNING, "Interrupted while locking\n");
213                 return -1;
214         }
215
216         error = idr_get_new(&p->pool, NULL, &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_session_init - initialize session
247  * @v9ses: session information structure
248  * @dev_name: device being mounted
249  * @data: options
250  *
251  */
252
253 int
254 v9fs_session_init(struct v9fs_session_info *v9ses,
255                   const char *dev_name, char *data)
256 {
257         struct v9fs_fcall *fcall = NULL;
258         struct v9fs_transport *trans_proto;
259         int n = 0;
260         int newfid = -1;
261         int retval = -EINVAL;
262
263         v9ses->name = __getname();
264         if (!v9ses->name)
265                 return -ENOMEM;
266
267         v9ses->remotename = __getname();
268         if (!v9ses->remotename) {
269                 putname(v9ses->name);
270                 return -ENOMEM;
271         }
272
273         strcpy(v9ses->name, V9FS_DEFUSER);
274         strcpy(v9ses->remotename, V9FS_DEFANAME);
275
276         v9fs_parse_options(data, v9ses);
277
278         /* set global debug level */
279         v9fs_debug_level = v9ses->debug;
280
281         /* id pools that are session-dependent: FIDs and TIDs */
282         idr_init(&v9ses->fidpool.pool);
283         init_MUTEX(&v9ses->fidpool.lock);
284         idr_init(&v9ses->tidpool.pool);
285         init_MUTEX(&v9ses->tidpool.lock);
286
287
288         switch (v9ses->proto) {
289         case PROTO_TCP:
290                 trans_proto = &v9fs_trans_tcp;
291                 break;
292         case PROTO_UNIX:
293                 trans_proto = &v9fs_trans_unix;
294                 *v9ses->remotename = 0;
295                 break;
296         case PROTO_FD:
297                 trans_proto = &v9fs_trans_fd;
298                 *v9ses->remotename = 0;
299                 break;
300         default:
301                 printk(KERN_ERR "v9fs: Bad mount protocol %d\n", v9ses->proto);
302                 retval = -ENOPROTOOPT;
303                 goto SessCleanUp;
304         };
305
306         v9ses->transport = trans_proto;
307
308         if ((retval = v9ses->transport->init(v9ses, dev_name, data)) < 0) {
309                 eprintk(KERN_ERR, "problem initializing transport\n");
310                 goto SessCleanUp;
311         }
312
313         v9ses->inprogress = 0;
314         v9ses->shutdown = 0;
315         v9ses->session_hung = 0;
316
317         if ((retval = v9fs_mux_init(v9ses, dev_name)) < 0) {
318                 dprintk(DEBUG_ERROR, "problem initializing mux\n");
319                 goto SessCleanUp;
320         }
321
322         if (v9ses->afid == ~0) {
323                 if (v9ses->extended)
324                         retval =
325                             v9fs_t_version(v9ses, v9ses->maxdata, "9P2000.u",
326                                            &fcall);
327                 else
328                         retval = v9fs_t_version(v9ses, v9ses->maxdata, "9P2000",
329                                                 &fcall);
330
331                 if (retval < 0) {
332                         dprintk(DEBUG_ERROR, "v9fs_t_version failed\n");
333                         goto FreeFcall;
334                 }
335
336                 /* Really should check for 9P1 and report error */
337                 if (!strcmp(fcall->params.rversion.version, "9P2000.u")) {
338                         dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
339                         v9ses->extended = 1;
340                 } else {
341                         dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
342                         v9ses->extended = 0;
343                 }
344
345                 n = fcall->params.rversion.msize;
346                 kfree(fcall);
347
348                 if (n < v9ses->maxdata)
349                         v9ses->maxdata = n;
350         }
351
352         newfid = v9fs_get_idpool(&v9ses->fidpool);
353         if (newfid < 0) {
354                 eprintk(KERN_WARNING, "couldn't allocate FID\n");
355                 retval = -ENOMEM;
356                 goto SessCleanUp;
357         }
358         /* it is a little bit ugly, but we have to prevent newfid */
359         /* being the same as afid, so if it is, get a new fid     */
360         if (v9ses->afid != ~0 && newfid == v9ses->afid) {
361                 newfid = v9fs_get_idpool(&v9ses->fidpool);
362                 if (newfid < 0) {
363                         eprintk(KERN_WARNING, "couldn't allocate FID\n");
364                         retval = -ENOMEM;
365                         goto SessCleanUp;
366                 }
367         }
368
369         if ((retval =
370              v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
371                            v9ses->afid, NULL))
372             < 0) {
373                 dprintk(DEBUG_ERROR, "cannot attach\n");
374                 goto SessCleanUp;
375         }
376
377         if (v9ses->afid != ~0) {
378                 if (v9fs_t_clunk(v9ses, v9ses->afid, NULL))
379                         dprintk(DEBUG_ERROR, "clunk failed\n");
380         }
381
382         return newfid;
383
384       FreeFcall:
385         kfree(fcall);
386
387       SessCleanUp:
388         v9fs_session_close(v9ses);
389         return retval;
390 }
391
392 /**
393  * v9fs_session_close - shutdown a session
394  * @v9ses: session information structure
395  *
396  */
397
398 void v9fs_session_close(struct v9fs_session_info *v9ses)
399 {
400         if (v9ses->recvproc) {
401                 send_sig(SIGKILL, v9ses->recvproc, 1);
402                 wait_for_completion(&v9ses->proccmpl);
403         }
404
405         if (v9ses->transport)
406                 v9ses->transport->close(v9ses->transport);
407
408         putname(v9ses->name);
409         putname(v9ses->remotename);
410 }
411
412 /**
413  * v9fs_session_cancel - mark transport as disconnected
414  *      and cancel all pending requests.
415  */
416 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
417         v9ses->transport->status = Disconnected;
418         v9fs_mux_cancel_requests(v9ses, -EIO);
419 }
420
421 extern int v9fs_error_init(void);
422
423 /**
424  * v9fs_init - Initialize module
425  *
426  */
427
428 static int __init init_v9fs(void)
429 {
430         v9fs_error_init();
431
432         printk(KERN_INFO "Installing v9fs 9P2000 file system support\n");
433
434         return register_filesystem(&v9fs_fs_type);
435 }
436
437 /**
438  * v9fs_init - shutdown module
439  *
440  */
441
442 static void __exit exit_v9fs(void)
443 {
444         unregister_filesystem(&v9fs_fs_type);
445 }
446
447 module_init(init_v9fs)
448 module_exit(exit_v9fs)
449
450 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
451 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
452 MODULE_LICENSE("GPL");