[PATCH] v9fs: simplify fid mapping
[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=%x"},
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         struct v9fs_str *version;
273
274         v9ses->name = __getname();
275         if (!v9ses->name)
276                 return -ENOMEM;
277
278         v9ses->remotename = __getname();
279         if (!v9ses->remotename) {
280                 __putname(v9ses->name);
281                 return -ENOMEM;
282         }
283
284         strcpy(v9ses->name, V9FS_DEFUSER);
285         strcpy(v9ses->remotename, V9FS_DEFANAME);
286
287         v9fs_parse_options(data, v9ses);
288
289         /* set global debug level */
290         v9fs_debug_level = v9ses->debug;
291
292         /* id pools that are session-dependent: FIDs and TIDs */
293         idr_init(&v9ses->fidpool.pool);
294         init_MUTEX(&v9ses->fidpool.lock);
295
296         switch (v9ses->proto) {
297         case PROTO_TCP:
298                 trans_proto = &v9fs_trans_tcp;
299                 break;
300         case PROTO_UNIX:
301                 trans_proto = &v9fs_trans_unix;
302                 *v9ses->remotename = 0;
303                 break;
304         case PROTO_FD:
305                 trans_proto = &v9fs_trans_fd;
306                 *v9ses->remotename = 0;
307                 break;
308         default:
309                 printk(KERN_ERR "v9fs: Bad mount protocol %d\n", v9ses->proto);
310                 retval = -ENOPROTOOPT;
311                 goto SessCleanUp;
312         };
313
314         v9ses->transport = kmalloc(sizeof(*v9ses->transport), GFP_KERNEL);
315         if (!v9ses->transport) {
316                 retval = -ENOMEM;
317                 goto SessCleanUp;
318         }
319
320         memmove(v9ses->transport, trans_proto, sizeof(*v9ses->transport));
321
322         if ((retval = v9ses->transport->init(v9ses, dev_name, data)) < 0) {
323                 eprintk(KERN_ERR, "problem initializing transport\n");
324                 goto SessCleanUp;
325         }
326
327         v9ses->inprogress = 0;
328         v9ses->shutdown = 0;
329         v9ses->session_hung = 0;
330
331         v9ses->mux = v9fs_mux_init(v9ses->transport, v9ses->maxdata + V9FS_IOHDRSZ,
332                 &v9ses->extended);
333
334         if (IS_ERR(v9ses->mux)) {
335                 retval = PTR_ERR(v9ses->mux);
336                 v9ses->mux = NULL;
337                 dprintk(DEBUG_ERROR, "problem initializing mux\n");
338                 goto SessCleanUp;
339         }
340
341         if (v9ses->afid == ~0) {
342                 if (v9ses->extended)
343                         retval =
344                             v9fs_t_version(v9ses, v9ses->maxdata, "9P2000.u",
345                                            &fcall);
346                 else
347                         retval = v9fs_t_version(v9ses, v9ses->maxdata, "9P2000",
348                                                 &fcall);
349
350                 if (retval < 0) {
351                         dprintk(DEBUG_ERROR, "v9fs_t_version failed\n");
352                         goto FreeFcall;
353                 }
354
355                 version = &fcall->params.rversion.version;
356                 if (version->len==8 && !memcmp(version->str, "9P2000.u", 8)) {
357                         dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
358                         v9ses->extended = 1;
359                 } else if (version->len==6 && !memcmp(version->str, "9P2000", 6)) {
360                         dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
361                         v9ses->extended = 0;
362                 } else {
363                         retval = -EREMOTEIO;
364                         goto FreeFcall;
365                 }
366
367                 n = fcall->params.rversion.msize;
368                 kfree(fcall);
369
370                 if (n < v9ses->maxdata)
371                         v9ses->maxdata = n;
372         }
373
374         newfid = v9fs_get_idpool(&v9ses->fidpool);
375         if (newfid < 0) {
376                 eprintk(KERN_WARNING, "couldn't allocate FID\n");
377                 retval = -ENOMEM;
378                 goto SessCleanUp;
379         }
380         /* it is a little bit ugly, but we have to prevent newfid */
381         /* being the same as afid, so if it is, get a new fid     */
382         if (v9ses->afid != ~0 && newfid == v9ses->afid) {
383                 newfid = v9fs_get_idpool(&v9ses->fidpool);
384                 if (newfid < 0) {
385                         eprintk(KERN_WARNING, "couldn't allocate FID\n");
386                         retval = -ENOMEM;
387                         goto SessCleanUp;
388                 }
389         }
390
391         if ((retval =
392              v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
393                            v9ses->afid, NULL))
394             < 0) {
395                 dprintk(DEBUG_ERROR, "cannot attach\n");
396                 goto SessCleanUp;
397         }
398
399         if (v9ses->afid != ~0) {
400                 dprintk(DEBUG_ERROR, "afid not equal to ~0\n");
401                 if (v9fs_t_clunk(v9ses, v9ses->afid))
402                         dprintk(DEBUG_ERROR, "clunk failed\n");
403         }
404
405         return newfid;
406
407       FreeFcall:
408         kfree(fcall);
409
410       SessCleanUp:
411         v9fs_session_close(v9ses);
412         return retval;
413 }
414
415 /**
416  * v9fs_session_close - shutdown a session
417  * @v9ses: session information structure
418  *
419  */
420
421 void v9fs_session_close(struct v9fs_session_info *v9ses)
422 {
423         if (v9ses->mux) {
424                 v9fs_mux_destroy(v9ses->mux);
425                 v9ses->mux = NULL;
426         }
427
428         if (v9ses->transport) {
429                 v9ses->transport->close(v9ses->transport);
430                 kfree(v9ses->transport);
431                 v9ses->transport = NULL;
432         }
433
434         __putname(v9ses->name);
435         __putname(v9ses->remotename);
436 }
437
438 /**
439  * v9fs_session_cancel - mark transport as disconnected
440  *      and cancel all pending requests.
441  */
442 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
443         dprintk(DEBUG_ERROR, "cancel session %p\n", v9ses);
444         v9ses->transport->status = Disconnected;
445         v9fs_mux_cancel(v9ses->mux, -EIO);
446 }
447
448 extern int v9fs_error_init(void);
449
450 /**
451  * v9fs_init - Initialize module
452  *
453  */
454
455 static int __init init_v9fs(void)
456 {
457         int ret;
458
459         v9fs_error_init();
460
461         printk(KERN_INFO "Installing v9fs 9P2000 file system support\n");
462
463         ret = v9fs_mux_global_init();
464         if (!ret)
465                 ret = register_filesystem(&v9fs_fs_type);
466
467         return ret;
468 }
469
470 /**
471  * v9fs_init - shutdown module
472  *
473  */
474
475 static void __exit exit_v9fs(void)
476 {
477         v9fs_mux_global_exit();
478         unregister_filesystem(&v9fs_fs_type);
479 }
480
481 module_init(init_v9fs)
482 module_exit(exit_v9fs)
483
484 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
485 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
486 MODULE_LICENSE("GPL");