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9P: introduction of a new cache=mmap model.
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1 /*
2  *  linux/fs/9p/v9fs.c
3  *
4  *  This file contains functions assisting in mapping VFS to 9P2000
5  *
6  *  Copyright (C) 2004-2008 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 version 2
11  *  as published by the Free Software Foundation.
12  *
13  *  This program is distributed in the hope that it will be useful,
14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *  GNU General Public License for more details.
17  *
18  *  You should have received a copy of the GNU General Public License
19  *  along with this program; if not, write to:
20  *  Free Software Foundation
21  *  51 Franklin Street, Fifth Floor
22  *  Boston, MA  02111-1301  USA
23  *
24  */
25
26 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27
28 #include <linux/module.h>
29 #include <linux/errno.h>
30 #include <linux/fs.h>
31 #include <linux/sched.h>
32 #include <linux/parser.h>
33 #include <linux/idr.h>
34 #include <linux/slab.h>
35 #include <net/9p/9p.h>
36 #include <net/9p/client.h>
37 #include <net/9p/transport.h>
38 #include "v9fs.h"
39 #include "v9fs_vfs.h"
40 #include "cache.h"
41
42 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
43 static LIST_HEAD(v9fs_sessionlist);
44 struct kmem_cache *v9fs_inode_cache;
45
46 /*
47  * Option Parsing (code inspired by NFS code)
48  *  NOTE: each transport will parse its own options
49  */
50
51 enum {
52         /* Options that take integer arguments */
53         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
54         /* String options */
55         Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
56         /* Options that take no arguments */
57         Opt_nodevmap,
58         /* Cache options */
59         Opt_cache_loose, Opt_fscache, Opt_mmap,
60         /* Access options */
61         Opt_access, Opt_posixacl,
62         /* Error token */
63         Opt_err
64 };
65
66 static const match_table_t tokens = {
67         {Opt_debug, "debug=%x"},
68         {Opt_dfltuid, "dfltuid=%u"},
69         {Opt_dfltgid, "dfltgid=%u"},
70         {Opt_afid, "afid=%u"},
71         {Opt_uname, "uname=%s"},
72         {Opt_remotename, "aname=%s"},
73         {Opt_nodevmap, "nodevmap"},
74         {Opt_cache, "cache=%s"},
75         {Opt_cache_loose, "loose"},
76         {Opt_fscache, "fscache"},
77         {Opt_mmap, "mmap"},
78         {Opt_cachetag, "cachetag=%s"},
79         {Opt_access, "access=%s"},
80         {Opt_posixacl, "posixacl"},
81         {Opt_err, NULL}
82 };
83
84 /* Interpret mount options for cache mode */
85 static int get_cache_mode(char *s)
86 {
87         int version = -EINVAL;
88
89         if (!strcmp(s, "loose")) {
90                 version = CACHE_LOOSE;
91                 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
92         } else if (!strcmp(s, "fscache")) {
93                 version = CACHE_FSCACHE;
94                 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
95         } else if (!strcmp(s, "mmap")) {
96                 version = CACHE_MMAP;
97                 p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
98         } else if (!strcmp(s, "none")) {
99                 version = CACHE_NONE;
100                 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
101         } else
102                 pr_info("Unknown Cache mode %s\n", s);
103         return version;
104 }
105
106 /**
107  * v9fs_parse_options - parse mount options into session structure
108  * @v9ses: existing v9fs session information
109  *
110  * Return 0 upon success, -ERRNO upon failure.
111  */
112
113 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
114 {
115         char *options, *tmp_options;
116         substring_t args[MAX_OPT_ARGS];
117         char *p;
118         int option = 0;
119         char *s, *e;
120         int ret = 0;
121
122         /* setup defaults */
123         v9ses->afid = ~0;
124         v9ses->debug = 0;
125         v9ses->cache = CACHE_NONE;
126 #ifdef CONFIG_9P_FSCACHE
127         v9ses->cachetag = NULL;
128 #endif
129
130         if (!opts)
131                 return 0;
132
133         tmp_options = kstrdup(opts, GFP_KERNEL);
134         if (!tmp_options) {
135                 ret = -ENOMEM;
136                 goto fail_option_alloc;
137         }
138         options = tmp_options;
139
140         while ((p = strsep(&options, ",")) != NULL) {
141                 int token, r;
142                 if (!*p)
143                         continue;
144                 token = match_token(p, tokens, args);
145                 switch (token) {
146                 case Opt_debug:
147                         r = match_int(&args[0], &option);
148                         if (r < 0) {
149                                 p9_debug(P9_DEBUG_ERROR,
150                                          "integer field, but no integer?\n");
151                                 ret = r;
152                                 continue;
153                         }
154                         v9ses->debug = option;
155 #ifdef CONFIG_NET_9P_DEBUG
156                         p9_debug_level = option;
157 #endif
158                         break;
159
160                 case Opt_dfltuid:
161                         r = match_int(&args[0], &option);
162                         if (r < 0) {
163                                 p9_debug(P9_DEBUG_ERROR,
164                                          "integer field, but no integer?\n");
165                                 ret = r;
166                                 continue;
167                         }
168                         v9ses->dfltuid = make_kuid(current_user_ns(), option);
169                         if (!uid_valid(v9ses->dfltuid)) {
170                                 p9_debug(P9_DEBUG_ERROR,
171                                          "uid field, but not a uid?\n");
172                                 ret = -EINVAL;
173                                 continue;
174                         }
175                         break;
176                 case Opt_dfltgid:
177                         r = match_int(&args[0], &option);
178                         if (r < 0) {
179                                 p9_debug(P9_DEBUG_ERROR,
180                                          "integer field, but no integer?\n");
181                                 ret = r;
182                                 continue;
183                         }
184                         v9ses->dfltgid = make_kgid(current_user_ns(), option);
185                         if (!gid_valid(v9ses->dfltgid)) {
186                                 p9_debug(P9_DEBUG_ERROR,
187                                          "gid field, but not a gid?\n");
188                                 ret = -EINVAL;
189                                 continue;
190                         }
191                         break;
192                 case Opt_afid:
193                         r = match_int(&args[0], &option);
194                         if (r < 0) {
195                                 p9_debug(P9_DEBUG_ERROR,
196                                          "integer field, but no integer?\n");
197                                 ret = r;
198                                 continue;
199                         }
200                         v9ses->afid = option;
201                         break;
202                 case Opt_uname:
203                         kfree(v9ses->uname);
204                         v9ses->uname = match_strdup(&args[0]);
205                         if (!v9ses->uname) {
206                                 ret = -ENOMEM;
207                                 goto free_and_return;
208                         }
209                         break;
210                 case Opt_remotename:
211                         kfree(v9ses->aname);
212                         v9ses->aname = match_strdup(&args[0]);
213                         if (!v9ses->aname) {
214                                 ret = -ENOMEM;
215                                 goto free_and_return;
216                         }
217                         break;
218                 case Opt_nodevmap:
219                         v9ses->nodev = 1;
220                         break;
221                 case Opt_cache_loose:
222                         v9ses->cache = CACHE_LOOSE;
223                         break;
224                 case Opt_fscache:
225                         v9ses->cache = CACHE_FSCACHE;
226                         break;
227                 case Opt_mmap:
228                         v9ses->cache = CACHE_MMAP;
229                         break;
230                 case Opt_cachetag:
231 #ifdef CONFIG_9P_FSCACHE
232                         v9ses->cachetag = match_strdup(&args[0]);
233 #endif
234                         break;
235                 case Opt_cache:
236                         s = match_strdup(&args[0]);
237                         if (!s) {
238                                 ret = -ENOMEM;
239                                 p9_debug(P9_DEBUG_ERROR,
240                                          "problem allocating copy of cache arg\n");
241                                 goto free_and_return;
242                         }
243                         ret = get_cache_mode(s);
244                         if (ret == -EINVAL) {
245                                 kfree(s);
246                                 goto free_and_return;
247                         }
248
249                         v9ses->cache = ret;
250                         kfree(s);
251                         break;
252
253                 case Opt_access:
254                         s = match_strdup(&args[0]);
255                         if (!s) {
256                                 ret = -ENOMEM;
257                                 p9_debug(P9_DEBUG_ERROR,
258                                          "problem allocating copy of access arg\n");
259                                 goto free_and_return;
260                         }
261
262                         v9ses->flags &= ~V9FS_ACCESS_MASK;
263                         if (strcmp(s, "user") == 0)
264                                 v9ses->flags |= V9FS_ACCESS_USER;
265                         else if (strcmp(s, "any") == 0)
266                                 v9ses->flags |= V9FS_ACCESS_ANY;
267                         else if (strcmp(s, "client") == 0) {
268                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
269                         } else {
270                                 uid_t uid;
271                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
272                                 uid = simple_strtoul(s, &e, 10);
273                                 if (*e != '\0') {
274                                         ret = -EINVAL;
275                                         pr_info("Unknown access argument %s\n",
276                                                 s);
277                                         kfree(s);
278                                         goto free_and_return;
279                                 }
280                                 v9ses->uid = make_kuid(current_user_ns(), uid);
281                                 if (!uid_valid(v9ses->uid)) {
282                                         ret = -EINVAL;
283                                         pr_info("Uknown uid %s\n", s);
284                                         kfree(s);
285                                         goto free_and_return;
286                                 }
287                         }
288
289                         kfree(s);
290                         break;
291
292                 case Opt_posixacl:
293 #ifdef CONFIG_9P_FS_POSIX_ACL
294                         v9ses->flags |= V9FS_POSIX_ACL;
295 #else
296                         p9_debug(P9_DEBUG_ERROR,
297                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
298 #endif
299                         break;
300
301                 default:
302                         continue;
303                 }
304         }
305
306 free_and_return:
307         kfree(tmp_options);
308 fail_option_alloc:
309         return ret;
310 }
311
312 /**
313  * v9fs_session_init - initialize session
314  * @v9ses: session information structure
315  * @dev_name: device being mounted
316  * @data: options
317  *
318  */
319
320 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
321                   const char *dev_name, char *data)
322 {
323         int retval = -EINVAL;
324         struct p9_fid *fid;
325         int rc;
326
327         v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
328         if (!v9ses->uname)
329                 return ERR_PTR(-ENOMEM);
330
331         v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
332         if (!v9ses->aname) {
333                 kfree(v9ses->uname);
334                 return ERR_PTR(-ENOMEM);
335         }
336         init_rwsem(&v9ses->rename_sem);
337
338         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
339         if (rc) {
340                 kfree(v9ses->aname);
341                 kfree(v9ses->uname);
342                 return ERR_PTR(rc);
343         }
344
345         spin_lock(&v9fs_sessionlist_lock);
346         list_add(&v9ses->slist, &v9fs_sessionlist);
347         spin_unlock(&v9fs_sessionlist_lock);
348
349         v9ses->uid = INVALID_UID;
350         v9ses->dfltuid = V9FS_DEFUID;
351         v9ses->dfltgid = V9FS_DEFGID;
352
353         v9ses->clnt = p9_client_create(dev_name, data);
354         if (IS_ERR(v9ses->clnt)) {
355                 retval = PTR_ERR(v9ses->clnt);
356                 v9ses->clnt = NULL;
357                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
358                 goto error;
359         }
360
361         v9ses->flags = V9FS_ACCESS_USER;
362
363         if (p9_is_proto_dotl(v9ses->clnt)) {
364                 v9ses->flags = V9FS_ACCESS_CLIENT;
365                 v9ses->flags |= V9FS_PROTO_2000L;
366         } else if (p9_is_proto_dotu(v9ses->clnt)) {
367                 v9ses->flags |= V9FS_PROTO_2000U;
368         }
369
370         rc = v9fs_parse_options(v9ses, data);
371         if (rc < 0) {
372                 retval = rc;
373                 goto error;
374         }
375
376         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
377
378         if (!v9fs_proto_dotl(v9ses) &&
379             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
380                 /*
381                  * We support ACCESS_CLIENT only for dotl.
382                  * Fall back to ACCESS_USER
383                  */
384                 v9ses->flags &= ~V9FS_ACCESS_MASK;
385                 v9ses->flags |= V9FS_ACCESS_USER;
386         }
387         /*FIXME !! */
388         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
389         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
390                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
391
392                 v9ses->flags &= ~V9FS_ACCESS_MASK;
393                 v9ses->flags |= V9FS_ACCESS_ANY;
394                 v9ses->uid = INVALID_UID;
395         }
396         if (!v9fs_proto_dotl(v9ses) ||
397                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
398                 /*
399                  * We support ACL checks on clinet only if the protocol is
400                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
401                  */
402                 v9ses->flags &= ~V9FS_ACL_MASK;
403         }
404
405         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
406                                                         v9ses->aname);
407         if (IS_ERR(fid)) {
408                 retval = PTR_ERR(fid);
409                 fid = NULL;
410                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
411                 goto error;
412         }
413
414         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
415                 fid->uid = v9ses->uid;
416         else
417                 fid->uid = INVALID_UID;
418
419 #ifdef CONFIG_9P_FSCACHE
420         /* register the session for caching */
421         v9fs_cache_session_get_cookie(v9ses);
422 #endif
423
424         return fid;
425
426 error:
427         bdi_destroy(&v9ses->bdi);
428         return ERR_PTR(retval);
429 }
430
431 /**
432  * v9fs_session_close - shutdown a session
433  * @v9ses: session information structure
434  *
435  */
436
437 void v9fs_session_close(struct v9fs_session_info *v9ses)
438 {
439         if (v9ses->clnt) {
440                 p9_client_destroy(v9ses->clnt);
441                 v9ses->clnt = NULL;
442         }
443
444 #ifdef CONFIG_9P_FSCACHE
445         if (v9ses->fscache) {
446                 v9fs_cache_session_put_cookie(v9ses);
447                 kfree(v9ses->cachetag);
448         }
449 #endif
450         kfree(v9ses->uname);
451         kfree(v9ses->aname);
452
453         bdi_destroy(&v9ses->bdi);
454
455         spin_lock(&v9fs_sessionlist_lock);
456         list_del(&v9ses->slist);
457         spin_unlock(&v9fs_sessionlist_lock);
458 }
459
460 /**
461  * v9fs_session_cancel - terminate a session
462  * @v9ses: session to terminate
463  *
464  * mark transport as disconnected and cancel all pending requests.
465  */
466
467 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
468         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
469         p9_client_disconnect(v9ses->clnt);
470 }
471
472 /**
473  * v9fs_session_begin_cancel - Begin terminate of a session
474  * @v9ses: session to terminate
475  *
476  * After this call we don't allow any request other than clunk.
477  */
478
479 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
480 {
481         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
482         p9_client_begin_disconnect(v9ses->clnt);
483 }
484
485 extern int v9fs_error_init(void);
486
487 static struct kobject *v9fs_kobj;
488
489 #ifdef CONFIG_9P_FSCACHE
490 /**
491  * caches_show - list caches associated with a session
492  *
493  * Returns the size of buffer written.
494  */
495
496 static ssize_t caches_show(struct kobject *kobj,
497                            struct kobj_attribute *attr,
498                            char *buf)
499 {
500         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
501         struct v9fs_session_info *v9ses;
502
503         spin_lock(&v9fs_sessionlist_lock);
504         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
505                 if (v9ses->cachetag) {
506                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
507                         if (n < 0) {
508                                 count = n;
509                                 break;
510                         }
511
512                         count += n;
513                         limit -= n;
514                 }
515         }
516
517         spin_unlock(&v9fs_sessionlist_lock);
518         return count;
519 }
520
521 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
522 #endif /* CONFIG_9P_FSCACHE */
523
524 static struct attribute *v9fs_attrs[] = {
525 #ifdef CONFIG_9P_FSCACHE
526         &v9fs_attr_cache.attr,
527 #endif
528         NULL,
529 };
530
531 static struct attribute_group v9fs_attr_group = {
532         .attrs = v9fs_attrs,
533 };
534
535 /**
536  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
537  *
538  */
539
540 static int v9fs_sysfs_init(void)
541 {
542         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
543         if (!v9fs_kobj)
544                 return -ENOMEM;
545
546         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
547                 kobject_put(v9fs_kobj);
548                 return -ENOMEM;
549         }
550
551         return 0;
552 }
553
554 /**
555  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
556  *
557  */
558
559 static void v9fs_sysfs_cleanup(void)
560 {
561         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
562         kobject_put(v9fs_kobj);
563 }
564
565 static void v9fs_inode_init_once(void *foo)
566 {
567         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
568 #ifdef CONFIG_9P_FSCACHE
569         v9inode->fscache = NULL;
570 #endif
571         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
572         inode_init_once(&v9inode->vfs_inode);
573 }
574
575 /**
576  * v9fs_init_inode_cache - initialize a cache for 9P
577  * Returns 0 on success.
578  */
579 static int v9fs_init_inode_cache(void)
580 {
581         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
582                                           sizeof(struct v9fs_inode),
583                                           0, (SLAB_RECLAIM_ACCOUNT|
584                                               SLAB_MEM_SPREAD),
585                                           v9fs_inode_init_once);
586         if (!v9fs_inode_cache)
587                 return -ENOMEM;
588
589         return 0;
590 }
591
592 /**
593  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
594  *
595  */
596 static void v9fs_destroy_inode_cache(void)
597 {
598         /*
599          * Make sure all delayed rcu free inodes are flushed before we
600          * destroy cache.
601          */
602         rcu_barrier();
603         kmem_cache_destroy(v9fs_inode_cache);
604 }
605
606 static int v9fs_cache_register(void)
607 {
608         int ret;
609         ret = v9fs_init_inode_cache();
610         if (ret < 0)
611                 return ret;
612 #ifdef CONFIG_9P_FSCACHE
613         ret = fscache_register_netfs(&v9fs_cache_netfs);
614         if (ret < 0)
615                 v9fs_destroy_inode_cache();
616 #endif
617         return ret;
618 }
619
620 static void v9fs_cache_unregister(void)
621 {
622         v9fs_destroy_inode_cache();
623 #ifdef CONFIG_9P_FSCACHE
624         fscache_unregister_netfs(&v9fs_cache_netfs);
625 #endif
626 }
627
628 /**
629  * init_v9fs - Initialize module
630  *
631  */
632
633 static int __init init_v9fs(void)
634 {
635         int err;
636         pr_info("Installing v9fs 9p2000 file system support\n");
637         /* TODO: Setup list of registered trasnport modules */
638
639         err = v9fs_cache_register();
640         if (err < 0) {
641                 pr_err("Failed to register v9fs for caching\n");
642                 return err;
643         }
644
645         err = v9fs_sysfs_init();
646         if (err < 0) {
647                 pr_err("Failed to register with sysfs\n");
648                 goto out_cache;
649         }
650         err = register_filesystem(&v9fs_fs_type);
651         if (err < 0) {
652                 pr_err("Failed to register filesystem\n");
653                 goto out_sysfs_cleanup;
654         }
655
656         return 0;
657
658 out_sysfs_cleanup:
659         v9fs_sysfs_cleanup();
660
661 out_cache:
662         v9fs_cache_unregister();
663
664         return err;
665 }
666
667 /**
668  * exit_v9fs - shutdown module
669  *
670  */
671
672 static void __exit exit_v9fs(void)
673 {
674         v9fs_sysfs_cleanup();
675         v9fs_cache_unregister();
676         unregister_filesystem(&v9fs_fs_type);
677 }
678
679 module_init(init_v9fs)
680 module_exit(exit_v9fs)
681
682 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
683 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
684 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
685 MODULE_LICENSE("GPL");