1 /* AFS superblock handling
2 *
3 * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
4 *
5 * This software may be freely redistributed under the terms of the
6 * GNU General Public License.
7 *
8 * You should have received a copy of the GNU General Public License
9 * along with this program; if not, write to the Free Software
10 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
11 *
12 * Authors: David Howells <dhowells@redhat.com>
13 * David Woodhouse <dwmw2@infradead.org>
14 *
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/mount.h>
20 #include <linux/init.h>
21 #include <linux/slab.h>
22 #include <linux/fs.h>
23 #include <linux/pagemap.h>
24 #include <linux/parser.h>
25 #include <linux/statfs.h>
26 #include <linux/sched.h>
27 #include "internal.h"
28
29 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
30
31 static void afs_i_init_once(void *foo);
32 static struct dentry *afs_mount(struct file_system_type *fs_type,
33 int flags, const char *dev_name, void *data);
34 static void afs_kill_super(struct super_block *sb);
35 static struct inode *afs_alloc_inode(struct super_block *sb);
36 static void afs_destroy_inode(struct inode *inode);
37 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
38
39 struct file_system_type afs_fs_type = {
40 .owner = THIS_MODULE,
41 .name = "afs",
42 .mount = afs_mount,
43 .kill_sb = afs_kill_super,
44 .fs_flags = 0,
45 };
46
47 static const struct super_operations afs_super_ops = {
48 .statfs = afs_statfs,
49 .alloc_inode = afs_alloc_inode,
50 .drop_inode = afs_drop_inode,
51 .destroy_inode = afs_destroy_inode,
52 .evict_inode = afs_evict_inode,
53 .show_options = generic_show_options,
54 };
55
56 static struct kmem_cache *afs_inode_cachep;
57 static atomic_t afs_count_active_inodes;
58
59 enum {
60 afs_no_opt,
61 afs_opt_cell,
62 afs_opt_rwpath,
63 afs_opt_vol,
64 afs_opt_autocell,
65 };
66
67 static const match_table_t afs_options_list = {
68 { afs_opt_cell, "cell=%s" },
69 { afs_opt_rwpath, "rwpath" },
70 { afs_opt_vol, "vol=%s" },
71 { afs_opt_autocell, "autocell" },
72 { afs_no_opt, NULL },
73 };
74
75 /*
76 * initialise the filesystem
77 */
afs_fs_init(void)78 int __init afs_fs_init(void)
79 {
80 int ret;
81
82 _enter("");
83
84 /* create ourselves an inode cache */
85 atomic_set(&afs_count_active_inodes, 0);
86
87 ret = -ENOMEM;
88 afs_inode_cachep = kmem_cache_create("afs_inode_cache",
89 sizeof(struct afs_vnode),
90 0,
91 SLAB_HWCACHE_ALIGN,
92 afs_i_init_once);
93 if (!afs_inode_cachep) {
94 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
95 return ret;
96 }
97
98 /* now export our filesystem to lesser mortals */
99 ret = register_filesystem(&afs_fs_type);
100 if (ret < 0) {
101 kmem_cache_destroy(afs_inode_cachep);
102 _leave(" = %d", ret);
103 return ret;
104 }
105
106 _leave(" = 0");
107 return 0;
108 }
109
110 /*
111 * clean up the filesystem
112 */
afs_fs_exit(void)113 void __exit afs_fs_exit(void)
114 {
115 _enter("");
116
117 afs_mntpt_kill_timer();
118 unregister_filesystem(&afs_fs_type);
119
120 if (atomic_read(&afs_count_active_inodes) != 0) {
121 printk("kAFS: %d active inode objects still present\n",
122 atomic_read(&afs_count_active_inodes));
123 BUG();
124 }
125
126 kmem_cache_destroy(afs_inode_cachep);
127 _leave("");
128 }
129
130 /*
131 * parse the mount options
132 * - this function has been shamelessly adapted from the ext3 fs which
133 * shamelessly adapted it from the msdos fs
134 */
afs_parse_options(struct afs_mount_params * params,char * options,const char ** devname)135 static int afs_parse_options(struct afs_mount_params *params,
136 char *options, const char **devname)
137 {
138 struct afs_cell *cell;
139 substring_t args[MAX_OPT_ARGS];
140 char *p;
141 int token;
142
143 _enter("%s", options);
144
145 options[PAGE_SIZE - 1] = 0;
146
147 while ((p = strsep(&options, ","))) {
148 if (!*p)
149 continue;
150
151 token = match_token(p, afs_options_list, args);
152 switch (token) {
153 case afs_opt_cell:
154 cell = afs_cell_lookup(args[0].from,
155 args[0].to - args[0].from,
156 false);
157 if (IS_ERR(cell))
158 return PTR_ERR(cell);
159 afs_put_cell(params->cell);
160 params->cell = cell;
161 break;
162
163 case afs_opt_rwpath:
164 params->rwpath = 1;
165 break;
166
167 case afs_opt_vol:
168 *devname = args[0].from;
169 break;
170
171 case afs_opt_autocell:
172 params->autocell = 1;
173 break;
174
175 default:
176 printk(KERN_ERR "kAFS:"
177 " Unknown or invalid mount option: '%s'\n", p);
178 return -EINVAL;
179 }
180 }
181
182 _leave(" = 0");
183 return 0;
184 }
185
186 /*
187 * parse a device name to get cell name, volume name, volume type and R/W
188 * selector
189 * - this can be one of the following:
190 * "%[cell:]volume[.]" R/W volume
191 * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0),
192 * or R/W (rwpath=1) volume
193 * "%[cell:]volume.readonly" R/O volume
194 * "#[cell:]volume.readonly" R/O volume
195 * "%[cell:]volume.backup" Backup volume
196 * "#[cell:]volume.backup" Backup volume
197 */
afs_parse_device_name(struct afs_mount_params * params,const char * name)198 static int afs_parse_device_name(struct afs_mount_params *params,
199 const char *name)
200 {
201 struct afs_cell *cell;
202 const char *cellname, *suffix;
203 int cellnamesz;
204
205 _enter(",%s", name);
206
207 if (!name) {
208 printk(KERN_ERR "kAFS: no volume name specified\n");
209 return -EINVAL;
210 }
211
212 if ((name[0] != '%' && name[0] != '#') || !name[1]) {
213 printk(KERN_ERR "kAFS: unparsable volume name\n");
214 return -EINVAL;
215 }
216
217 /* determine the type of volume we're looking for */
218 params->type = AFSVL_ROVOL;
219 params->force = false;
220 if (params->rwpath || name[0] == '%') {
221 params->type = AFSVL_RWVOL;
222 params->force = true;
223 }
224 name++;
225
226 /* split the cell name out if there is one */
227 params->volname = strchr(name, ':');
228 if (params->volname) {
229 cellname = name;
230 cellnamesz = params->volname - name;
231 params->volname++;
232 } else {
233 params->volname = name;
234 cellname = NULL;
235 cellnamesz = 0;
236 }
237
238 /* the volume type is further affected by a possible suffix */
239 suffix = strrchr(params->volname, '.');
240 if (suffix) {
241 if (strcmp(suffix, ".readonly") == 0) {
242 params->type = AFSVL_ROVOL;
243 params->force = true;
244 } else if (strcmp(suffix, ".backup") == 0) {
245 params->type = AFSVL_BACKVOL;
246 params->force = true;
247 } else if (suffix[1] == 0) {
248 } else {
249 suffix = NULL;
250 }
251 }
252
253 params->volnamesz = suffix ?
254 suffix - params->volname : strlen(params->volname);
255
256 _debug("cell %*.*s [%p]",
257 cellnamesz, cellnamesz, cellname ?: "", params->cell);
258
259 /* lookup the cell record */
260 if (cellname || !params->cell) {
261 cell = afs_cell_lookup(cellname, cellnamesz, true);
262 if (IS_ERR(cell)) {
263 printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
264 cellnamesz, cellnamesz, cellname ?: "");
265 return PTR_ERR(cell);
266 }
267 afs_put_cell(params->cell);
268 params->cell = cell;
269 }
270
271 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
272 params->cell->name, params->cell,
273 params->volnamesz, params->volnamesz, params->volname,
274 suffix ?: "-", params->type, params->force ? " FORCE" : "");
275
276 return 0;
277 }
278
279 /*
280 * check a superblock to see if it's the one we're looking for
281 */
afs_test_super(struct super_block * sb,void * data)282 static int afs_test_super(struct super_block *sb, void *data)
283 {
284 struct afs_super_info *as1 = data;
285 struct afs_super_info *as = sb->s_fs_info;
286
287 return as->volume == as1->volume;
288 }
289
afs_set_super(struct super_block * sb,void * data)290 static int afs_set_super(struct super_block *sb, void *data)
291 {
292 sb->s_fs_info = data;
293 return set_anon_super(sb, NULL);
294 }
295
296 /*
297 * fill in the superblock
298 */
afs_fill_super(struct super_block * sb,struct afs_mount_params * params)299 static int afs_fill_super(struct super_block *sb,
300 struct afs_mount_params *params)
301 {
302 struct afs_super_info *as = sb->s_fs_info;
303 struct afs_fid fid;
304 struct inode *inode = NULL;
305 int ret;
306
307 _enter("");
308
309 /* fill in the superblock */
310 sb->s_blocksize = PAGE_CACHE_SIZE;
311 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
312 sb->s_magic = AFS_FS_MAGIC;
313 sb->s_op = &afs_super_ops;
314 sb->s_bdi = &as->volume->bdi;
315 strlcpy(sb->s_id, as->volume->vlocation->vldb.name, sizeof(sb->s_id));
316
317 /* allocate the root inode and dentry */
318 fid.vid = as->volume->vid;
319 fid.vnode = 1;
320 fid.unique = 1;
321 inode = afs_iget(sb, params->key, &fid, NULL, NULL);
322 if (IS_ERR(inode))
323 return PTR_ERR(inode);
324
325 if (params->autocell)
326 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
327
328 ret = -ENOMEM;
329 sb->s_root = d_make_root(inode);
330 if (!sb->s_root)
331 goto error;
332
333 sb->s_d_op = &afs_fs_dentry_operations;
334
335 _leave(" = 0");
336 return 0;
337
338 error:
339 _leave(" = %d", ret);
340 return ret;
341 }
342
343 /*
344 * get an AFS superblock
345 */
afs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * options)346 static struct dentry *afs_mount(struct file_system_type *fs_type,
347 int flags, const char *dev_name, void *options)
348 {
349 struct afs_mount_params params;
350 struct super_block *sb;
351 struct afs_volume *vol;
352 struct key *key;
353 char *new_opts = kstrdup(options, GFP_KERNEL);
354 struct afs_super_info *as;
355 int ret;
356
357 _enter(",,%s,%p", dev_name, options);
358
359 memset(¶ms, 0, sizeof(params));
360
361 /* parse the options and device name */
362 if (options) {
363 ret = afs_parse_options(¶ms, options, &dev_name);
364 if (ret < 0)
365 goto error;
366 }
367
368 ret = afs_parse_device_name(¶ms, dev_name);
369 if (ret < 0)
370 goto error;
371
372 /* try and do the mount securely */
373 key = afs_request_key(params.cell);
374 if (IS_ERR(key)) {
375 _leave(" = %ld [key]", PTR_ERR(key));
376 ret = PTR_ERR(key);
377 goto error;
378 }
379 params.key = key;
380
381 /* parse the device name */
382 vol = afs_volume_lookup(¶ms);
383 if (IS_ERR(vol)) {
384 ret = PTR_ERR(vol);
385 goto error;
386 }
387
388 /* allocate a superblock info record */
389 as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
390 if (!as) {
391 ret = -ENOMEM;
392 afs_put_volume(vol);
393 goto error;
394 }
395 as->volume = vol;
396
397 /* allocate a deviceless superblock */
398 sb = sget(fs_type, afs_test_super, afs_set_super, as);
399 if (IS_ERR(sb)) {
400 ret = PTR_ERR(sb);
401 afs_put_volume(vol);
402 kfree(as);
403 goto error;
404 }
405
406 if (!sb->s_root) {
407 /* initial superblock/root creation */
408 _debug("create");
409 sb->s_flags = flags;
410 ret = afs_fill_super(sb, ¶ms);
411 if (ret < 0) {
412 deactivate_locked_super(sb);
413 goto error;
414 }
415 save_mount_options(sb, new_opts);
416 sb->s_flags |= MS_ACTIVE;
417 } else {
418 _debug("reuse");
419 ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
420 afs_put_volume(vol);
421 kfree(as);
422 }
423
424 afs_put_cell(params.cell);
425 kfree(new_opts);
426 _leave(" = 0 [%p]", sb);
427 return dget(sb->s_root);
428
429 error:
430 afs_put_cell(params.cell);
431 key_put(params.key);
432 kfree(new_opts);
433 _leave(" = %d", ret);
434 return ERR_PTR(ret);
435 }
436
afs_kill_super(struct super_block * sb)437 static void afs_kill_super(struct super_block *sb)
438 {
439 struct afs_super_info *as = sb->s_fs_info;
440 kill_anon_super(sb);
441 afs_put_volume(as->volume);
442 kfree(as);
443 }
444
445 /*
446 * initialise an inode cache slab element prior to any use
447 */
afs_i_init_once(void * _vnode)448 static void afs_i_init_once(void *_vnode)
449 {
450 struct afs_vnode *vnode = _vnode;
451
452 memset(vnode, 0, sizeof(*vnode));
453 inode_init_once(&vnode->vfs_inode);
454 init_waitqueue_head(&vnode->update_waitq);
455 mutex_init(&vnode->permits_lock);
456 mutex_init(&vnode->validate_lock);
457 spin_lock_init(&vnode->writeback_lock);
458 spin_lock_init(&vnode->lock);
459 INIT_LIST_HEAD(&vnode->writebacks);
460 INIT_LIST_HEAD(&vnode->pending_locks);
461 INIT_LIST_HEAD(&vnode->granted_locks);
462 INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
463 INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
464 }
465
466 /*
467 * allocate an AFS inode struct from our slab cache
468 */
afs_alloc_inode(struct super_block * sb)469 static struct inode *afs_alloc_inode(struct super_block *sb)
470 {
471 struct afs_vnode *vnode;
472
473 vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
474 if (!vnode)
475 return NULL;
476
477 atomic_inc(&afs_count_active_inodes);
478
479 memset(&vnode->fid, 0, sizeof(vnode->fid));
480 memset(&vnode->status, 0, sizeof(vnode->status));
481
482 vnode->volume = NULL;
483 vnode->update_cnt = 0;
484 vnode->flags = 1 << AFS_VNODE_UNSET;
485 vnode->cb_promised = false;
486
487 _leave(" = %p", &vnode->vfs_inode);
488 return &vnode->vfs_inode;
489 }
490
afs_i_callback(struct rcu_head * head)491 static void afs_i_callback(struct rcu_head *head)
492 {
493 struct inode *inode = container_of(head, struct inode, i_rcu);
494 struct afs_vnode *vnode = AFS_FS_I(inode);
495 kmem_cache_free(afs_inode_cachep, vnode);
496 }
497
498 /*
499 * destroy an AFS inode struct
500 */
afs_destroy_inode(struct inode * inode)501 static void afs_destroy_inode(struct inode *inode)
502 {
503 struct afs_vnode *vnode = AFS_FS_I(inode);
504
505 _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
506
507 _debug("DESTROY INODE %p", inode);
508
509 ASSERTCMP(vnode->server, ==, NULL);
510
511 call_rcu(&inode->i_rcu, afs_i_callback);
512 atomic_dec(&afs_count_active_inodes);
513 }
514
515 /*
516 * return information about an AFS volume
517 */
afs_statfs(struct dentry * dentry,struct kstatfs * buf)518 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
519 {
520 struct afs_volume_status vs;
521 struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
522 struct key *key;
523 int ret;
524
525 key = afs_request_key(vnode->volume->cell);
526 if (IS_ERR(key))
527 return PTR_ERR(key);
528
529 ret = afs_vnode_get_volume_status(vnode, key, &vs);
530 key_put(key);
531 if (ret < 0) {
532 _leave(" = %d", ret);
533 return ret;
534 }
535
536 buf->f_type = dentry->d_sb->s_magic;
537 buf->f_bsize = AFS_BLOCK_SIZE;
538 buf->f_namelen = AFSNAMEMAX - 1;
539
540 if (vs.max_quota == 0)
541 buf->f_blocks = vs.part_max_blocks;
542 else
543 buf->f_blocks = vs.max_quota;
544 buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
545 return 0;
546 }
547