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TOMOYO Linux Cross Reference
Linux/fs/afs/super.c

Version: ~ [ linux-5.5-rc7 ] ~ [ linux-5.4.13 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.97 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.166 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.210 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.210 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.81 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  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 <linux/nsproxy.h>
 28 #include <linux/magic.h>
 29 #include <net/net_namespace.h>
 30 #include "internal.h"
 31 
 32 static void afs_i_init_once(void *foo);
 33 static struct dentry *afs_mount(struct file_system_type *fs_type,
 34                       int flags, const char *dev_name, void *data);
 35 static void afs_kill_super(struct super_block *sb);
 36 static struct inode *afs_alloc_inode(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 static int afs_show_devname(struct seq_file *m, struct dentry *root);
 40 static int afs_show_options(struct seq_file *m, struct dentry *root);
 41 
 42 struct file_system_type afs_fs_type = {
 43         .owner          = THIS_MODULE,
 44         .name           = "afs",
 45         .mount          = afs_mount,
 46         .kill_sb        = afs_kill_super,
 47         .fs_flags       = 0,
 48 };
 49 MODULE_ALIAS_FS("afs");
 50 
 51 int afs_net_id;
 52 
 53 static const struct super_operations afs_super_ops = {
 54         .statfs         = afs_statfs,
 55         .alloc_inode    = afs_alloc_inode,
 56         .drop_inode     = afs_drop_inode,
 57         .destroy_inode  = afs_destroy_inode,
 58         .evict_inode    = afs_evict_inode,
 59         .show_devname   = afs_show_devname,
 60         .show_options   = afs_show_options,
 61 };
 62 
 63 static struct kmem_cache *afs_inode_cachep;
 64 static atomic_t afs_count_active_inodes;
 65 
 66 enum {
 67         afs_no_opt,
 68         afs_opt_cell,
 69         afs_opt_dyn,
 70         afs_opt_rwpath,
 71         afs_opt_vol,
 72         afs_opt_autocell,
 73 };
 74 
 75 static const match_table_t afs_options_list = {
 76         { afs_opt_cell,         "cell=%s"       },
 77         { afs_opt_dyn,          "dyn"           },
 78         { afs_opt_rwpath,       "rwpath"        },
 79         { afs_opt_vol,          "vol=%s"        },
 80         { afs_opt_autocell,     "autocell"      },
 81         { afs_no_opt,           NULL            },
 82 };
 83 
 84 /*
 85  * initialise the filesystem
 86  */
 87 int __init afs_fs_init(void)
 88 {
 89         int ret;
 90 
 91         _enter("");
 92 
 93         /* create ourselves an inode cache */
 94         atomic_set(&afs_count_active_inodes, 0);
 95 
 96         ret = -ENOMEM;
 97         afs_inode_cachep = kmem_cache_create("afs_inode_cache",
 98                                              sizeof(struct afs_vnode),
 99                                              0,
100                                              SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
101                                              afs_i_init_once);
102         if (!afs_inode_cachep) {
103                 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
104                 return ret;
105         }
106 
107         /* now export our filesystem to lesser mortals */
108         ret = register_filesystem(&afs_fs_type);
109         if (ret < 0) {
110                 kmem_cache_destroy(afs_inode_cachep);
111                 _leave(" = %d", ret);
112                 return ret;
113         }
114 
115         _leave(" = 0");
116         return 0;
117 }
118 
119 /*
120  * clean up the filesystem
121  */
122 void afs_fs_exit(void)
123 {
124         _enter("");
125 
126         afs_mntpt_kill_timer();
127         unregister_filesystem(&afs_fs_type);
128 
129         if (atomic_read(&afs_count_active_inodes) != 0) {
130                 printk("kAFS: %d active inode objects still present\n",
131                        atomic_read(&afs_count_active_inodes));
132                 BUG();
133         }
134 
135         /*
136          * Make sure all delayed rcu free inodes are flushed before we
137          * destroy cache.
138          */
139         rcu_barrier();
140         kmem_cache_destroy(afs_inode_cachep);
141         _leave("");
142 }
143 
144 /*
145  * Display the mount device name in /proc/mounts.
146  */
147 static int afs_show_devname(struct seq_file *m, struct dentry *root)
148 {
149         struct afs_super_info *as = AFS_FS_S(root->d_sb);
150         struct afs_volume *volume = as->volume;
151         struct afs_cell *cell = as->cell;
152         const char *suf = "";
153         char pref = '%';
154 
155         if (as->dyn_root) {
156                 seq_puts(m, "none");
157                 return 0;
158         }
159 
160         switch (volume->type) {
161         case AFSVL_RWVOL:
162                 break;
163         case AFSVL_ROVOL:
164                 pref = '#';
165                 if (volume->type_force)
166                         suf = ".readonly";
167                 break;
168         case AFSVL_BACKVOL:
169                 pref = '#';
170                 suf = ".backup";
171                 break;
172         }
173 
174         seq_printf(m, "%c%s:%s%s", pref, cell->name, volume->name, suf);
175         return 0;
176 }
177 
178 /*
179  * Display the mount options in /proc/mounts.
180  */
181 static int afs_show_options(struct seq_file *m, struct dentry *root)
182 {
183         struct afs_super_info *as = AFS_FS_S(root->d_sb);
184 
185         if (as->dyn_root)
186                 seq_puts(m, ",dyn");
187         if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
188                 seq_puts(m, ",autocell");
189         return 0;
190 }
191 
192 /*
193  * parse the mount options
194  * - this function has been shamelessly adapted from the ext3 fs which
195  *   shamelessly adapted it from the msdos fs
196  */
197 static int afs_parse_options(struct afs_mount_params *params,
198                              char *options, const char **devname)
199 {
200         struct afs_cell *cell;
201         substring_t args[MAX_OPT_ARGS];
202         char *p;
203         int token;
204 
205         _enter("%s", options);
206 
207         options[PAGE_SIZE - 1] = 0;
208 
209         while ((p = strsep(&options, ","))) {
210                 if (!*p)
211                         continue;
212 
213                 token = match_token(p, afs_options_list, args);
214                 switch (token) {
215                 case afs_opt_cell:
216                         rcu_read_lock();
217                         cell = afs_lookup_cell_rcu(params->net,
218                                                    args[0].from,
219                                                    args[0].to - args[0].from);
220                         rcu_read_unlock();
221                         if (IS_ERR(cell))
222                                 return PTR_ERR(cell);
223                         afs_put_cell(params->net, params->cell);
224                         params->cell = cell;
225                         break;
226 
227                 case afs_opt_rwpath:
228                         params->rwpath = true;
229                         break;
230 
231                 case afs_opt_vol:
232                         *devname = args[0].from;
233                         break;
234 
235                 case afs_opt_autocell:
236                         params->autocell = true;
237                         break;
238 
239                 case afs_opt_dyn:
240                         params->dyn_root = true;
241                         break;
242 
243                 default:
244                         printk(KERN_ERR "kAFS:"
245                                " Unknown or invalid mount option: '%s'\n", p);
246                         return -EINVAL;
247                 }
248         }
249 
250         _leave(" = 0");
251         return 0;
252 }
253 
254 /*
255  * parse a device name to get cell name, volume name, volume type and R/W
256  * selector
257  * - this can be one of the following:
258  *      "%[cell:]volume[.]"             R/W volume
259  *      "#[cell:]volume[.]"             R/O or R/W volume (rwpath=0),
260  *                                       or R/W (rwpath=1) volume
261  *      "%[cell:]volume.readonly"       R/O volume
262  *      "#[cell:]volume.readonly"       R/O volume
263  *      "%[cell:]volume.backup"         Backup volume
264  *      "#[cell:]volume.backup"         Backup volume
265  */
266 static int afs_parse_device_name(struct afs_mount_params *params,
267                                  const char *name)
268 {
269         struct afs_cell *cell;
270         const char *cellname, *suffix;
271         int cellnamesz;
272 
273         _enter(",%s", name);
274 
275         if (!name) {
276                 printk(KERN_ERR "kAFS: no volume name specified\n");
277                 return -EINVAL;
278         }
279 
280         if ((name[0] != '%' && name[0] != '#') || !name[1]) {
281                 printk(KERN_ERR "kAFS: unparsable volume name\n");
282                 return -EINVAL;
283         }
284 
285         /* determine the type of volume we're looking for */
286         params->type = AFSVL_ROVOL;
287         params->force = false;
288         if (params->rwpath || name[0] == '%') {
289                 params->type = AFSVL_RWVOL;
290                 params->force = true;
291         }
292         name++;
293 
294         /* split the cell name out if there is one */
295         params->volname = strchr(name, ':');
296         if (params->volname) {
297                 cellname = name;
298                 cellnamesz = params->volname - name;
299                 params->volname++;
300         } else {
301                 params->volname = name;
302                 cellname = NULL;
303                 cellnamesz = 0;
304         }
305 
306         /* the volume type is further affected by a possible suffix */
307         suffix = strrchr(params->volname, '.');
308         if (suffix) {
309                 if (strcmp(suffix, ".readonly") == 0) {
310                         params->type = AFSVL_ROVOL;
311                         params->force = true;
312                 } else if (strcmp(suffix, ".backup") == 0) {
313                         params->type = AFSVL_BACKVOL;
314                         params->force = true;
315                 } else if (suffix[1] == 0) {
316                 } else {
317                         suffix = NULL;
318                 }
319         }
320 
321         params->volnamesz = suffix ?
322                 suffix - params->volname : strlen(params->volname);
323 
324         _debug("cell %*.*s [%p]",
325                cellnamesz, cellnamesz, cellname ?: "", params->cell);
326 
327         /* lookup the cell record */
328         if (cellname || !params->cell) {
329                 cell = afs_lookup_cell(params->net, cellname, cellnamesz,
330                                        NULL, false);
331                 if (IS_ERR(cell)) {
332                         printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
333                                cellnamesz, cellnamesz, cellname ?: "");
334                         return PTR_ERR(cell);
335                 }
336                 afs_put_cell(params->net, params->cell);
337                 params->cell = cell;
338         }
339 
340         _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
341                params->cell->name, params->cell,
342                params->volnamesz, params->volnamesz, params->volname,
343                suffix ?: "-", params->type, params->force ? " FORCE" : "");
344 
345         return 0;
346 }
347 
348 /*
349  * check a superblock to see if it's the one we're looking for
350  */
351 static int afs_test_super(struct super_block *sb, void *data)
352 {
353         struct afs_super_info *as1 = data;
354         struct afs_super_info *as = AFS_FS_S(sb);
355 
356         return (as->net_ns == as1->net_ns &&
357                 as->volume &&
358                 as->volume->vid == as1->volume->vid &&
359                 !as->dyn_root);
360 }
361 
362 static int afs_dynroot_test_super(struct super_block *sb, void *data)
363 {
364         struct afs_super_info *as1 = data;
365         struct afs_super_info *as = AFS_FS_S(sb);
366 
367         return (as->net_ns == as1->net_ns &&
368                 as->dyn_root);
369 }
370 
371 static int afs_set_super(struct super_block *sb, void *data)
372 {
373         struct afs_super_info *as = data;
374 
375         sb->s_fs_info = as;
376         return set_anon_super(sb, NULL);
377 }
378 
379 /*
380  * fill in the superblock
381  */
382 static int afs_fill_super(struct super_block *sb,
383                           struct afs_mount_params *params)
384 {
385         struct afs_super_info *as = AFS_FS_S(sb);
386         struct afs_fid fid;
387         struct inode *inode = NULL;
388         int ret;
389 
390         _enter("");
391 
392         /* fill in the superblock */
393         sb->s_blocksize         = PAGE_SIZE;
394         sb->s_blocksize_bits    = PAGE_SHIFT;
395         sb->s_magic             = AFS_FS_MAGIC;
396         sb->s_op                = &afs_super_ops;
397         if (!as->dyn_root)
398                 sb->s_xattr     = afs_xattr_handlers;
399         ret = super_setup_bdi(sb);
400         if (ret)
401                 return ret;
402         sb->s_bdi->ra_pages     = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
403 
404         /* allocate the root inode and dentry */
405         if (as->dyn_root) {
406                 inode = afs_iget_pseudo_dir(sb, true);
407                 sb->s_flags     |= SB_RDONLY;
408         } else {
409                 sprintf(sb->s_id, "%llu", as->volume->vid);
410                 afs_activate_volume(as->volume);
411                 fid.vid         = as->volume->vid;
412                 fid.vnode       = 1;
413                 fid.vnode_hi    = 0;
414                 fid.unique      = 1;
415                 inode = afs_iget(sb, params->key, &fid, NULL, NULL, NULL);
416         }
417 
418         if (IS_ERR(inode))
419                 return PTR_ERR(inode);
420 
421         if (params->autocell || params->dyn_root)
422                 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
423 
424         ret = -ENOMEM;
425         sb->s_root = d_make_root(inode);
426         if (!sb->s_root)
427                 goto error;
428 
429         if (as->dyn_root) {
430                 sb->s_d_op = &afs_dynroot_dentry_operations;
431                 ret = afs_dynroot_populate(sb);
432                 if (ret < 0)
433                         goto error;
434         } else {
435                 sb->s_d_op = &afs_fs_dentry_operations;
436         }
437 
438         _leave(" = 0");
439         return 0;
440 
441 error:
442         _leave(" = %d", ret);
443         return ret;
444 }
445 
446 static struct afs_super_info *afs_alloc_sbi(struct afs_mount_params *params)
447 {
448         struct afs_super_info *as;
449 
450         as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
451         if (as) {
452                 as->net_ns = get_net(params->net_ns);
453                 if (params->dyn_root)
454                         as->dyn_root = true;
455                 else
456                         as->cell = afs_get_cell(params->cell);
457         }
458         return as;
459 }
460 
461 static void afs_destroy_sbi(struct afs_super_info *as)
462 {
463         if (as) {
464                 afs_put_volume(as->cell, as->volume);
465                 afs_put_cell(afs_net(as->net_ns), as->cell);
466                 put_net(as->net_ns);
467                 kfree(as);
468         }
469 }
470 
471 static void afs_kill_super(struct super_block *sb)
472 {
473         struct afs_super_info *as = AFS_FS_S(sb);
474         struct afs_net *net = afs_net(as->net_ns);
475 
476         if (as->dyn_root)
477                 afs_dynroot_depopulate(sb);
478         
479         /* Clear the callback interests (which will do ilookup5) before
480          * deactivating the superblock.
481          */
482         if (as->volume)
483                 afs_clear_callback_interests(net, as->volume->servers);
484         kill_anon_super(sb);
485         if (as->volume)
486                 afs_deactivate_volume(as->volume);
487         afs_destroy_sbi(as);
488 }
489 
490 /*
491  * get an AFS superblock
492  */
493 static struct dentry *afs_mount(struct file_system_type *fs_type,
494                                 int flags, const char *dev_name, void *options)
495 {
496         struct afs_mount_params params;
497         struct super_block *sb;
498         struct afs_volume *candidate;
499         struct key *key;
500         struct afs_super_info *as;
501         int ret;
502 
503         _enter(",,%s,%p", dev_name, options);
504 
505         memset(&params, 0, sizeof(params));
506 
507         ret = -EINVAL;
508         if (current->nsproxy->net_ns != &init_net)
509                 goto error;
510         params.net_ns = current->nsproxy->net_ns;
511         params.net = afs_net(params.net_ns);
512         
513         /* parse the options and device name */
514         if (options) {
515                 ret = afs_parse_options(&params, options, &dev_name);
516                 if (ret < 0)
517                         goto error;
518         }
519 
520         if (!params.dyn_root) {
521                 ret = afs_parse_device_name(&params, dev_name);
522                 if (ret < 0)
523                         goto error;
524 
525                 /* try and do the mount securely */
526                 key = afs_request_key(params.cell);
527                 if (IS_ERR(key)) {
528                         _leave(" = %ld [key]", PTR_ERR(key));
529                         ret = PTR_ERR(key);
530                         goto error;
531                 }
532                 params.key = key;
533         }
534 
535         /* allocate a superblock info record */
536         ret = -ENOMEM;
537         as = afs_alloc_sbi(&params);
538         if (!as)
539                 goto error_key;
540 
541         if (!params.dyn_root) {
542                 /* Assume we're going to need a volume record; at the very
543                  * least we can use it to update the volume record if we have
544                  * one already.  This checks that the volume exists within the
545                  * cell.
546                  */
547                 candidate = afs_create_volume(&params);
548                 if (IS_ERR(candidate)) {
549                         ret = PTR_ERR(candidate);
550                         goto error_as;
551                 }
552 
553                 as->volume = candidate;
554         }
555 
556         /* allocate a deviceless superblock */
557         sb = sget(fs_type,
558                   as->dyn_root ? afs_dynroot_test_super : afs_test_super,
559                   afs_set_super, flags, as);
560         if (IS_ERR(sb)) {
561                 ret = PTR_ERR(sb);
562                 goto error_as;
563         }
564 
565         if (!sb->s_root) {
566                 /* initial superblock/root creation */
567                 _debug("create");
568                 ret = afs_fill_super(sb, &params);
569                 if (ret < 0)
570                         goto error_sb;
571                 as = NULL;
572                 sb->s_flags |= SB_ACTIVE;
573         } else {
574                 _debug("reuse");
575                 ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
576                 afs_destroy_sbi(as);
577                 as = NULL;
578         }
579 
580         afs_put_cell(params.net, params.cell);
581         key_put(params.key);
582         _leave(" = 0 [%p]", sb);
583         return dget(sb->s_root);
584 
585 error_sb:
586         deactivate_locked_super(sb);
587         goto error_key;
588 error_as:
589         afs_destroy_sbi(as);
590 error_key:
591         key_put(params.key);
592 error:
593         afs_put_cell(params.net, params.cell);
594         _leave(" = %d", ret);
595         return ERR_PTR(ret);
596 }
597 
598 /*
599  * Initialise an inode cache slab element prior to any use.  Note that
600  * afs_alloc_inode() *must* reset anything that could incorrectly leak from one
601  * inode to another.
602  */
603 static void afs_i_init_once(void *_vnode)
604 {
605         struct afs_vnode *vnode = _vnode;
606 
607         memset(vnode, 0, sizeof(*vnode));
608         inode_init_once(&vnode->vfs_inode);
609         mutex_init(&vnode->io_lock);
610         init_rwsem(&vnode->validate_lock);
611         spin_lock_init(&vnode->wb_lock);
612         spin_lock_init(&vnode->lock);
613         INIT_LIST_HEAD(&vnode->wb_keys);
614         INIT_LIST_HEAD(&vnode->pending_locks);
615         INIT_LIST_HEAD(&vnode->granted_locks);
616         INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
617         seqlock_init(&vnode->cb_lock);
618 }
619 
620 /*
621  * allocate an AFS inode struct from our slab cache
622  */
623 static struct inode *afs_alloc_inode(struct super_block *sb)
624 {
625         struct afs_vnode *vnode;
626 
627         vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
628         if (!vnode)
629                 return NULL;
630 
631         atomic_inc(&afs_count_active_inodes);
632 
633         /* Reset anything that shouldn't leak from one inode to the next. */
634         memset(&vnode->fid, 0, sizeof(vnode->fid));
635         memset(&vnode->status, 0, sizeof(vnode->status));
636 
637         vnode->volume           = NULL;
638         vnode->lock_key         = NULL;
639         vnode->permit_cache     = NULL;
640         vnode->cb_interest      = NULL;
641 #ifdef CONFIG_AFS_FSCACHE
642         vnode->cache            = NULL;
643 #endif
644 
645         vnode->flags            = 1 << AFS_VNODE_UNSET;
646         vnode->cb_type          = 0;
647         vnode->lock_state       = AFS_VNODE_LOCK_NONE;
648 
649         _leave(" = %p", &vnode->vfs_inode);
650         return &vnode->vfs_inode;
651 }
652 
653 static void afs_i_callback(struct rcu_head *head)
654 {
655         struct inode *inode = container_of(head, struct inode, i_rcu);
656         struct afs_vnode *vnode = AFS_FS_I(inode);
657         kmem_cache_free(afs_inode_cachep, vnode);
658 }
659 
660 /*
661  * destroy an AFS inode struct
662  */
663 static void afs_destroy_inode(struct inode *inode)
664 {
665         struct afs_vnode *vnode = AFS_FS_I(inode);
666 
667         _enter("%p{%llx:%llu}", inode, vnode->fid.vid, vnode->fid.vnode);
668 
669         _debug("DESTROY INODE %p", inode);
670 
671         ASSERTCMP(vnode->cb_interest, ==, NULL);
672 
673         call_rcu(&inode->i_rcu, afs_i_callback);
674         atomic_dec(&afs_count_active_inodes);
675 }
676 
677 /*
678  * return information about an AFS volume
679  */
680 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
681 {
682         struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
683         struct afs_fs_cursor fc;
684         struct afs_volume_status vs;
685         struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
686         struct key *key;
687         int ret;
688 
689         buf->f_type     = dentry->d_sb->s_magic;
690         buf->f_bsize    = AFS_BLOCK_SIZE;
691         buf->f_namelen  = AFSNAMEMAX - 1;
692 
693         if (as->dyn_root) {
694                 buf->f_blocks   = 1;
695                 buf->f_bavail   = 0;
696                 buf->f_bfree    = 0;
697                 return 0;
698         }
699 
700         key = afs_request_key(vnode->volume->cell);
701         if (IS_ERR(key))
702                 return PTR_ERR(key);
703 
704         ret = -ERESTARTSYS;
705         if (afs_begin_vnode_operation(&fc, vnode, key)) {
706                 fc.flags |= AFS_FS_CURSOR_NO_VSLEEP;
707                 while (afs_select_fileserver(&fc)) {
708                         fc.cb_break = afs_calc_vnode_cb_break(vnode);
709                         afs_fs_get_volume_status(&fc, &vs);
710                 }
711 
712                 afs_check_for_remote_deletion(&fc, fc.vnode);
713                 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
714                 ret = afs_end_vnode_operation(&fc);
715         }
716 
717         key_put(key);
718 
719         if (ret == 0) {
720                 if (vs.max_quota == 0)
721                         buf->f_blocks = vs.part_max_blocks;
722                 else
723                         buf->f_blocks = vs.max_quota;
724                 buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
725         }
726 
727         return ret;
728 }
729 

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