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/init.h>
20 #include <linux/slab.h>
21 #include <linux/smp_lock.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 int afs_get_sb(struct file_system_type *fs_type,
33 int flags, const char *dev_name,
34 void *data, struct vfsmount *mnt);
35 static struct inode *afs_alloc_inode(struct super_block *sb);
36 static void afs_put_super(struct super_block *sb);
37 static void afs_destroy_inode(struct inode *inode);
38 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
39
40 struct file_system_type afs_fs_type = {
41 .owner = THIS_MODULE,
42 .name = "afs",
43 .get_sb = afs_get_sb,
44 .kill_sb = kill_anon_super,
45 .fs_flags = 0,
46 };
47
48 static const struct super_operations afs_super_ops = {
49 .statfs = afs_statfs,
50 .alloc_inode = afs_alloc_inode,
51 .write_inode = afs_write_inode,
52 .destroy_inode = afs_destroy_inode,
53 .clear_inode = afs_clear_inode,
54 .put_super = afs_put_super,
55 .show_options = generic_show_options,
56 };
57
58 static struct kmem_cache *afs_inode_cachep;
59 static atomic_t afs_count_active_inodes;
60
61 enum {
62 afs_no_opt,
63 afs_opt_cell,
64 afs_opt_rwpath,
65 afs_opt_vol,
66 };
67
68 static const match_table_t afs_options_list = {
69 { afs_opt_cell, "cell=%s" },
70 { afs_opt_rwpath, "rwpath" },
71 { afs_opt_vol, "vol=%s" },
72 { afs_no_opt, NULL },
73 };
74
75 /*
76 * initialise the filesystem
77 */
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 */
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 */
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 if (IS_ERR(cell))
157 return PTR_ERR(cell);
158 afs_put_cell(params->cell);
159 params->cell = cell;
160 break;
161
162 case afs_opt_rwpath:
163 params->rwpath = 1;
164 break;
165
166 case afs_opt_vol:
167 *devname = args[0].from;
168 break;
169
170 default:
171 printk(KERN_ERR "kAFS:"
172 " Unknown or invalid mount option: '%s'\n", p);
173 return -EINVAL;
174 }
175 }
176
177 _leave(" = 0");
178 return 0;
179 }
180
181 /*
182 * parse a device name to get cell name, volume name, volume type and R/W
183 * selector
184 * - this can be one of the following:
185 * "%[cell:]volume[.]" R/W volume
186 * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0),
187 * or R/W (rwpath=1) volume
188 * "%[cell:]volume.readonly" R/O volume
189 * "#[cell:]volume.readonly" R/O volume
190 * "%[cell:]volume.backup" Backup volume
191 * "#[cell:]volume.backup" Backup volume
192 */
193 static int afs_parse_device_name(struct afs_mount_params *params,
194 const char *name)
195 {
196 struct afs_cell *cell;
197 const char *cellname, *suffix;
198 int cellnamesz;
199
200 _enter(",%s", name);
201
202 if (!name) {
203 printk(KERN_ERR "kAFS: no volume name specified\n");
204 return -EINVAL;
205 }
206
207 if ((name[0] != '%' && name[0] != '#') || !name[1]) {
208 printk(KERN_ERR "kAFS: unparsable volume name\n");
209 return -EINVAL;
210 }
211
212 /* determine the type of volume we're looking for */
213 params->type = AFSVL_ROVOL;
214 params->force = false;
215 if (params->rwpath || name[0] == '%') {
216 params->type = AFSVL_RWVOL;
217 params->force = true;
218 }
219 name++;
220
221 /* split the cell name out if there is one */
222 params->volname = strchr(name, ':');
223 if (params->volname) {
224 cellname = name;
225 cellnamesz = params->volname - name;
226 params->volname++;
227 } else {
228 params->volname = name;
229 cellname = NULL;
230 cellnamesz = 0;
231 }
232
233 /* the volume type is further affected by a possible suffix */
234 suffix = strrchr(params->volname, '.');
235 if (suffix) {
236 if (strcmp(suffix, ".readonly") == 0) {
237 params->type = AFSVL_ROVOL;
238 params->force = true;
239 } else if (strcmp(suffix, ".backup") == 0) {
240 params->type = AFSVL_BACKVOL;
241 params->force = true;
242 } else if (suffix[1] == 0) {
243 } else {
244 suffix = NULL;
245 }
246 }
247
248 params->volnamesz = suffix ?
249 suffix - params->volname : strlen(params->volname);
250
251 _debug("cell %*.*s [%p]",
252 cellnamesz, cellnamesz, cellname ?: "", params->cell);
253
254 /* lookup the cell record */
255 if (cellname || !params->cell) {
256 cell = afs_cell_lookup(cellname, cellnamesz);
257 if (IS_ERR(cell)) {
258 printk(KERN_ERR "kAFS: unable to lookup cell '%s'\n",
259 cellname ?: "");
260 return PTR_ERR(cell);
261 }
262 afs_put_cell(params->cell);
263 params->cell = cell;
264 }
265
266 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
267 params->cell->name, params->cell,
268 params->volnamesz, params->volnamesz, params->volname,
269 suffix ?: "-", params->type, params->force ? " FORCE" : "");
270
271 return 0;
272 }
273
274 /*
275 * check a superblock to see if it's the one we're looking for
276 */
277 static int afs_test_super(struct super_block *sb, void *data)
278 {
279 struct afs_mount_params *params = data;
280 struct afs_super_info *as = sb->s_fs_info;
281
282 return as->volume == params->volume;
283 }
284
285 /*
286 * fill in the superblock
287 */
288 static int afs_fill_super(struct super_block *sb, void *data)
289 {
290 struct afs_mount_params *params = data;
291 struct afs_super_info *as = NULL;
292 struct afs_fid fid;
293 struct dentry *root = NULL;
294 struct inode *inode = NULL;
295 int ret;
296
297 _enter("");
298
299 /* allocate a superblock info record */
300 as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
301 if (!as) {
302 _leave(" = -ENOMEM");
303 return -ENOMEM;
304 }
305
306 afs_get_volume(params->volume);
307 as->volume = params->volume;
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_fs_info = as;
315
316 /* allocate the root inode and dentry */
317 fid.vid = as->volume->vid;
318 fid.vnode = 1;
319 fid.unique = 1;
320 inode = afs_iget(sb, params->key, &fid, NULL, NULL);
321 if (IS_ERR(inode))
322 goto error_inode;
323
324 ret = -ENOMEM;
325 root = d_alloc_root(inode);
326 if (!root)
327 goto error;
328
329 sb->s_root = root;
330
331 _leave(" = 0");
332 return 0;
333
334 error_inode:
335 ret = PTR_ERR(inode);
336 inode = NULL;
337 error:
338 iput(inode);
339 afs_put_volume(as->volume);
340 kfree(as);
341
342 sb->s_fs_info = NULL;
343
344 _leave(" = %d", ret);
345 return ret;
346 }
347
348 /*
349 * get an AFS superblock
350 */
351 static int afs_get_sb(struct file_system_type *fs_type,
352 int flags,
353 const char *dev_name,
354 void *options,
355 struct vfsmount *mnt)
356 {
357 struct afs_mount_params params;
358 struct super_block *sb;
359 struct afs_volume *vol;
360 struct key *key;
361 char *new_opts = kstrdup(options, GFP_KERNEL);
362 int ret;
363
364 _enter(",,%s,%p", dev_name, options);
365
366 memset(¶ms, 0, sizeof(params));
367
368 /* parse the options and device name */
369 if (options) {
370 ret = afs_parse_options(¶ms, options, &dev_name);
371 if (ret < 0)
372 goto error;
373 }
374
375 ret = afs_parse_device_name(¶ms, dev_name);
376 if (ret < 0)
377 goto error;
378
379 /* try and do the mount securely */
380 key = afs_request_key(params.cell);
381 if (IS_ERR(key)) {
382 _leave(" = %ld [key]", PTR_ERR(key));
383 ret = PTR_ERR(key);
384 goto error;
385 }
386 params.key = key;
387
388 /* parse the device name */
389 vol = afs_volume_lookup(¶ms);
390 if (IS_ERR(vol)) {
391 ret = PTR_ERR(vol);
392 goto error;
393 }
394 params.volume = vol;
395
396 /* allocate a deviceless superblock */
397 sb = sget(fs_type, afs_test_super, set_anon_super, ¶ms);
398 if (IS_ERR(sb)) {
399 ret = PTR_ERR(sb);
400 goto error;
401 }
402
403 if (!sb->s_root) {
404 /* initial superblock/root creation */
405 _debug("create");
406 sb->s_flags = flags;
407 ret = afs_fill_super(sb, ¶ms);
408 if (ret < 0) {
409 deactivate_locked_super(sb);
410 goto error;
411 }
412 save_mount_options(sb, new_opts);
413 sb->s_flags |= MS_ACTIVE;
414 } else {
415 _debug("reuse");
416 ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
417 }
418
419 simple_set_mnt(mnt, sb);
420 afs_put_volume(params.volume);
421 afs_put_cell(params.cell);
422 kfree(new_opts);
423 _leave(" = 0 [%p]", sb);
424 return 0;
425
426 error:
427 afs_put_volume(params.volume);
428 afs_put_cell(params.cell);
429 key_put(params.key);
430 kfree(new_opts);
431 _leave(" = %d", ret);
432 return ret;
433 }
434
435 /*
436 * finish the unmounting process on the superblock
437 */
438 static void afs_put_super(struct super_block *sb)
439 {
440 struct afs_super_info *as = sb->s_fs_info;
441
442 _enter("");
443
444 lock_kernel();
445
446 afs_put_volume(as->volume);
447
448 unlock_kernel();
449
450 _leave("");
451 }
452
453 /*
454 * initialise an inode cache slab element prior to any use
455 */
456 static void afs_i_init_once(void *_vnode)
457 {
458 struct afs_vnode *vnode = _vnode;
459
460 memset(vnode, 0, sizeof(*vnode));
461 inode_init_once(&vnode->vfs_inode);
462 init_waitqueue_head(&vnode->update_waitq);
463 mutex_init(&vnode->permits_lock);
464 mutex_init(&vnode->validate_lock);
465 spin_lock_init(&vnode->writeback_lock);
466 spin_lock_init(&vnode->lock);
467 INIT_LIST_HEAD(&vnode->writebacks);
468 INIT_LIST_HEAD(&vnode->pending_locks);
469 INIT_LIST_HEAD(&vnode->granted_locks);
470 INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
471 INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
472 }
473
474 /*
475 * allocate an AFS inode struct from our slab cache
476 */
477 static struct inode *afs_alloc_inode(struct super_block *sb)
478 {
479 struct afs_vnode *vnode;
480
481 vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
482 if (!vnode)
483 return NULL;
484
485 atomic_inc(&afs_count_active_inodes);
486
487 memset(&vnode->fid, 0, sizeof(vnode->fid));
488 memset(&vnode->status, 0, sizeof(vnode->status));
489
490 vnode->volume = NULL;
491 vnode->update_cnt = 0;
492 vnode->flags = 1 << AFS_VNODE_UNSET;
493 vnode->cb_promised = false;
494
495 _leave(" = %p", &vnode->vfs_inode);
496 return &vnode->vfs_inode;
497 }
498
499 /*
500 * destroy an AFS inode struct
501 */
502 static void afs_destroy_inode(struct inode *inode)
503 {
504 struct afs_vnode *vnode = AFS_FS_I(inode);
505
506 _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
507
508 _debug("DESTROY INODE %p", inode);
509
510 ASSERTCMP(vnode->server, ==, NULL);
511
512 kmem_cache_free(afs_inode_cachep, vnode);
513 atomic_dec(&afs_count_active_inodes);
514 }
515
516 /*
517 * return information about an AFS volume
518 */
519 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
520 {
521 struct afs_volume_status vs;
522 struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
523 struct key *key;
524 int ret;
525
526 key = afs_request_key(vnode->volume->cell);
527 if (IS_ERR(key))
528 return PTR_ERR(key);
529
530 ret = afs_vnode_get_volume_status(vnode, key, &vs);
531 key_put(key);
532 if (ret < 0) {
533 _leave(" = %d", ret);
534 return ret;
535 }
536
537 buf->f_type = dentry->d_sb->s_magic;
538 buf->f_bsize = AFS_BLOCK_SIZE;
539 buf->f_namelen = AFSNAMEMAX - 1;
540
541 if (vs.max_quota == 0)
542 buf->f_blocks = vs.part_max_blocks;
543 else
544 buf->f_blocks = vs.max_quota;
545 buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
546 return 0;
547 }
548
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