xref: /linux/fs/afs/inode.c (revision 37744feebc086908fd89760650f458ab19071750)
1 /*
2  * Copyright (c) 2002 Red Hat, Inc. All rights reserved.
3  *
4  * This software may be freely redistributed under the terms of the
5  * GNU General Public License.
6  *
7  * You should have received a copy of the GNU General Public License
8  * along with this program; if not, write to the Free Software
9  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
10  *
11  * Authors: David Woodhouse <dwmw2@infradead.org>
12  *          David Howells <dhowells@redhat.com>
13  *
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/fs.h>
20 #include <linux/pagemap.h>
21 #include <linux/sched.h>
22 #include <linux/mount.h>
23 #include <linux/namei.h>
24 #include <linux/iversion.h>
25 #include "internal.h"
26 #include "afs_fs.h"
27 
28 static const struct inode_operations afs_symlink_inode_operations = {
29 	.get_link	= page_get_link,
30 	.listxattr	= afs_listxattr,
31 };
32 
33 static noinline void dump_vnode(struct afs_vnode *vnode, struct afs_vnode *parent_vnode)
34 {
35 	static unsigned long once_only;
36 
37 	pr_warn("kAFS: AFS vnode with undefined type %u\n", vnode->status.type);
38 	pr_warn("kAFS: A=%d m=%o s=%llx v=%llx\n",
39 		vnode->status.abort_code,
40 		vnode->status.mode,
41 		vnode->status.size,
42 		vnode->status.data_version);
43 	pr_warn("kAFS: vnode %llx:%llx:%x\n",
44 		vnode->fid.vid,
45 		vnode->fid.vnode,
46 		vnode->fid.unique);
47 	if (parent_vnode)
48 		pr_warn("kAFS: dir %llx:%llx:%x\n",
49 			parent_vnode->fid.vid,
50 			parent_vnode->fid.vnode,
51 			parent_vnode->fid.unique);
52 
53 	if (!test_and_set_bit(0, &once_only))
54 		dump_stack();
55 }
56 
57 /*
58  * Set the file size and block count.  Estimate the number of 512 bytes blocks
59  * used, rounded up to nearest 1K for consistency with other AFS clients.
60  */
61 static void afs_set_i_size(struct afs_vnode *vnode, u64 size)
62 {
63 	i_size_write(&vnode->vfs_inode, size);
64 	vnode->vfs_inode.i_blocks = ((size + 1023) >> 10) << 1;
65 }
66 
67 /*
68  * Initialise an inode from the vnode status.
69  */
70 static int afs_inode_init_from_status(struct afs_vnode *vnode, struct key *key,
71 				      struct afs_cb_interest *cbi,
72 				      struct afs_vnode *parent_vnode,
73 				      struct afs_status_cb *scb)
74 {
75 	struct afs_cb_interest *old_cbi = NULL;
76 	struct afs_file_status *status = &scb->status;
77 	struct inode *inode = AFS_VNODE_TO_I(vnode);
78 	struct timespec64 t;
79 
80 	_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
81 	       status->type,
82 	       status->nlink,
83 	       (unsigned long long) status->size,
84 	       status->data_version,
85 	       status->mode);
86 
87 	write_seqlock(&vnode->cb_lock);
88 
89 	vnode->status = *status;
90 
91 	t = status->mtime_client;
92 	inode->i_ctime = t;
93 	inode->i_mtime = t;
94 	inode->i_atime = t;
95 	inode->i_uid = make_kuid(&init_user_ns, status->owner);
96 	inode->i_gid = make_kgid(&init_user_ns, status->group);
97 	set_nlink(&vnode->vfs_inode, status->nlink);
98 
99 	switch (status->type) {
100 	case AFS_FTYPE_FILE:
101 		inode->i_mode	= S_IFREG | status->mode;
102 		inode->i_op	= &afs_file_inode_operations;
103 		inode->i_fop	= &afs_file_operations;
104 		inode->i_mapping->a_ops	= &afs_fs_aops;
105 		break;
106 	case AFS_FTYPE_DIR:
107 		inode->i_mode	= S_IFDIR | status->mode;
108 		inode->i_op	= &afs_dir_inode_operations;
109 		inode->i_fop	= &afs_dir_file_operations;
110 		inode->i_mapping->a_ops	= &afs_dir_aops;
111 		break;
112 	case AFS_FTYPE_SYMLINK:
113 		/* Symlinks with a mode of 0644 are actually mountpoints. */
114 		if ((status->mode & 0777) == 0644) {
115 			inode->i_flags |= S_AUTOMOUNT;
116 
117 			set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
118 
119 			inode->i_mode	= S_IFDIR | 0555;
120 			inode->i_op	= &afs_mntpt_inode_operations;
121 			inode->i_fop	= &afs_mntpt_file_operations;
122 			inode->i_mapping->a_ops	= &afs_fs_aops;
123 		} else {
124 			inode->i_mode	= S_IFLNK | status->mode;
125 			inode->i_op	= &afs_symlink_inode_operations;
126 			inode->i_mapping->a_ops	= &afs_fs_aops;
127 		}
128 		inode_nohighmem(inode);
129 		break;
130 	default:
131 		dump_vnode(vnode, parent_vnode);
132 		write_sequnlock(&vnode->cb_lock);
133 		return afs_protocol_error(NULL, -EBADMSG, afs_eproto_file_type);
134 	}
135 
136 	afs_set_i_size(vnode, status->size);
137 
138 	vnode->invalid_before	= status->data_version;
139 	inode_set_iversion_raw(&vnode->vfs_inode, status->data_version);
140 
141 	if (!scb->have_cb) {
142 		/* it's a symlink we just created (the fileserver
143 		 * didn't give us a callback) */
144 		vnode->cb_expires_at = ktime_get_real_seconds();
145 	} else {
146 		vnode->cb_expires_at = scb->callback.expires_at;
147 		old_cbi = rcu_dereference_protected(vnode->cb_interest,
148 						    lockdep_is_held(&vnode->cb_lock.lock));
149 		if (cbi != old_cbi)
150 			rcu_assign_pointer(vnode->cb_interest, afs_get_cb_interest(cbi));
151 		else
152 			old_cbi = NULL;
153 		set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
154 	}
155 
156 	write_sequnlock(&vnode->cb_lock);
157 	afs_put_cb_interest(afs_v2net(vnode), old_cbi);
158 	return 0;
159 }
160 
161 /*
162  * Update the core inode struct from a returned status record.
163  */
164 static void afs_apply_status(struct afs_fs_cursor *fc,
165 			     struct afs_vnode *vnode,
166 			     struct afs_status_cb *scb,
167 			     const afs_dataversion_t *expected_version)
168 {
169 	struct afs_file_status *status = &scb->status;
170 	struct timespec64 t;
171 	umode_t mode;
172 	bool data_changed = false;
173 
174 	BUG_ON(test_bit(AFS_VNODE_UNSET, &vnode->flags));
175 
176 	if (status->type != vnode->status.type) {
177 		pr_warn("Vnode %llx:%llx:%x changed type %u to %u\n",
178 			vnode->fid.vid,
179 			vnode->fid.vnode,
180 			vnode->fid.unique,
181 			status->type, vnode->status.type);
182 		afs_protocol_error(NULL, -EBADMSG, afs_eproto_bad_status);
183 		return;
184 	}
185 
186 	if (status->nlink != vnode->status.nlink)
187 		set_nlink(&vnode->vfs_inode, status->nlink);
188 
189 	if (status->owner != vnode->status.owner)
190 		vnode->vfs_inode.i_uid = make_kuid(&init_user_ns, status->owner);
191 
192 	if (status->group != vnode->status.group)
193 		vnode->vfs_inode.i_gid = make_kgid(&init_user_ns, status->group);
194 
195 	if (status->mode != vnode->status.mode) {
196 		mode = vnode->vfs_inode.i_mode;
197 		mode &= ~S_IALLUGO;
198 		mode |= status->mode;
199 		WRITE_ONCE(vnode->vfs_inode.i_mode, mode);
200 	}
201 
202 	t = status->mtime_client;
203 	vnode->vfs_inode.i_ctime = t;
204 	vnode->vfs_inode.i_mtime = t;
205 	vnode->vfs_inode.i_atime = t;
206 
207 	if (vnode->status.data_version != status->data_version)
208 		data_changed = true;
209 
210 	vnode->status = *status;
211 
212 	if (expected_version &&
213 	    *expected_version != status->data_version) {
214 		if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags))
215 			pr_warn("kAFS: vnode modified {%llx:%llu} %llx->%llx %s\n",
216 				vnode->fid.vid, vnode->fid.vnode,
217 				(unsigned long long)*expected_version,
218 				(unsigned long long)status->data_version,
219 				fc->type ? fc->type->name : "???");
220 
221 		vnode->invalid_before = status->data_version;
222 		if (vnode->status.type == AFS_FTYPE_DIR) {
223 			if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
224 				afs_stat_v(vnode, n_inval);
225 		} else {
226 			set_bit(AFS_VNODE_ZAP_DATA, &vnode->flags);
227 		}
228 	} else if (vnode->status.type == AFS_FTYPE_DIR) {
229 		/* Expected directory change is handled elsewhere so
230 		 * that we can locally edit the directory and save on a
231 		 * download.
232 		 */
233 		if (test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
234 			data_changed = false;
235 	}
236 
237 	if (data_changed) {
238 		inode_set_iversion_raw(&vnode->vfs_inode, status->data_version);
239 		afs_set_i_size(vnode, status->size);
240 	}
241 }
242 
243 /*
244  * Apply a callback to a vnode.
245  */
246 static void afs_apply_callback(struct afs_fs_cursor *fc,
247 			       struct afs_vnode *vnode,
248 			       struct afs_status_cb *scb,
249 			       unsigned int cb_break)
250 {
251 	struct afs_cb_interest *old;
252 	struct afs_callback *cb = &scb->callback;
253 
254 	if (!afs_cb_is_broken(cb_break, vnode, fc->cbi)) {
255 		vnode->cb_expires_at	= cb->expires_at;
256 		old = rcu_dereference_protected(vnode->cb_interest,
257 						lockdep_is_held(&vnode->cb_lock.lock));
258 		if (old != fc->cbi) {
259 			rcu_assign_pointer(vnode->cb_interest, afs_get_cb_interest(fc->cbi));
260 			afs_put_cb_interest(afs_v2net(vnode), old);
261 		}
262 		set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
263 	}
264 }
265 
266 /*
267  * Apply the received status and callback to an inode all in the same critical
268  * section to avoid races with afs_validate().
269  */
270 void afs_vnode_commit_status(struct afs_fs_cursor *fc,
271 			     struct afs_vnode *vnode,
272 			     unsigned int cb_break,
273 			     const afs_dataversion_t *expected_version,
274 			     struct afs_status_cb *scb)
275 {
276 	if (fc->ac.error != 0)
277 		return;
278 
279 	write_seqlock(&vnode->cb_lock);
280 
281 	if (scb->have_error) {
282 		if (scb->status.abort_code == VNOVNODE) {
283 			set_bit(AFS_VNODE_DELETED, &vnode->flags);
284 			clear_nlink(&vnode->vfs_inode);
285 			__afs_break_callback(vnode, afs_cb_break_for_deleted);
286 		}
287 	} else {
288 		if (scb->have_status)
289 			afs_apply_status(fc, vnode, scb, expected_version);
290 		if (scb->have_cb)
291 			afs_apply_callback(fc, vnode, scb, cb_break);
292 	}
293 
294 	write_sequnlock(&vnode->cb_lock);
295 
296 	if (fc->ac.error == 0 && scb->have_status)
297 		afs_cache_permit(vnode, fc->key, cb_break, scb);
298 }
299 
300 /*
301  * Fetch file status from the volume.
302  */
303 int afs_fetch_status(struct afs_vnode *vnode, struct key *key, bool is_new,
304 		     afs_access_t *_caller_access)
305 {
306 	struct afs_status_cb *scb;
307 	struct afs_fs_cursor fc;
308 	int ret;
309 
310 	_enter("%s,{%llx:%llu.%u,S=%lx}",
311 	       vnode->volume->name,
312 	       vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
313 	       vnode->flags);
314 
315 	scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL);
316 	if (!scb)
317 		return -ENOMEM;
318 
319 	ret = -ERESTARTSYS;
320 	if (afs_begin_vnode_operation(&fc, vnode, key, true)) {
321 		afs_dataversion_t data_version = vnode->status.data_version;
322 
323 		while (afs_select_fileserver(&fc)) {
324 			fc.cb_break = afs_calc_vnode_cb_break(vnode);
325 			afs_fs_fetch_file_status(&fc, scb, NULL);
326 		}
327 
328 		if (fc.error) {
329 			/* Do nothing. */
330 		} else if (is_new) {
331 			ret = afs_inode_init_from_status(vnode, key, fc.cbi,
332 							 NULL, scb);
333 			fc.error = ret;
334 			if (ret == 0)
335 				afs_cache_permit(vnode, key, fc.cb_break, scb);
336 		} else {
337 			afs_vnode_commit_status(&fc, vnode, fc.cb_break,
338 						&data_version, scb);
339 		}
340 		afs_check_for_remote_deletion(&fc, vnode);
341 		ret = afs_end_vnode_operation(&fc);
342 	}
343 
344 	if (ret == 0 && _caller_access)
345 		*_caller_access = scb->status.caller_access;
346 	kfree(scb);
347 	_leave(" = %d", ret);
348 	return ret;
349 }
350 
351 /*
352  * iget5() comparator
353  */
354 int afs_iget5_test(struct inode *inode, void *opaque)
355 {
356 	struct afs_iget_data *iget_data = opaque;
357 	struct afs_vnode *vnode = AFS_FS_I(inode);
358 
359 	return memcmp(&vnode->fid, &iget_data->fid, sizeof(iget_data->fid)) == 0;
360 }
361 
362 /*
363  * iget5() comparator for inode created by autocell operations
364  *
365  * These pseudo inodes don't match anything.
366  */
367 static int afs_iget5_pseudo_dir_test(struct inode *inode, void *opaque)
368 {
369 	return 0;
370 }
371 
372 /*
373  * iget5() inode initialiser
374  */
375 static int afs_iget5_set(struct inode *inode, void *opaque)
376 {
377 	struct afs_iget_data *iget_data = opaque;
378 	struct afs_vnode *vnode = AFS_FS_I(inode);
379 
380 	vnode->fid		= iget_data->fid;
381 	vnode->volume		= iget_data->volume;
382 	vnode->cb_v_break	= iget_data->cb_v_break;
383 	vnode->cb_s_break	= iget_data->cb_s_break;
384 
385 	/* YFS supports 96-bit vnode IDs, but Linux only supports
386 	 * 64-bit inode numbers.
387 	 */
388 	inode->i_ino		= iget_data->fid.vnode;
389 	inode->i_generation	= iget_data->fid.unique;
390 	return 0;
391 }
392 
393 /*
394  * Create an inode for a dynamic root directory or an autocell dynamic
395  * automount dir.
396  */
397 struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
398 {
399 	struct afs_super_info *as;
400 	struct afs_vnode *vnode;
401 	struct inode *inode;
402 	static atomic_t afs_autocell_ino;
403 
404 	struct afs_iget_data iget_data = {
405 		.cb_v_break = 0,
406 		.cb_s_break = 0,
407 	};
408 
409 	_enter("");
410 
411 	as = sb->s_fs_info;
412 	if (as->volume) {
413 		iget_data.volume = as->volume;
414 		iget_data.fid.vid = as->volume->vid;
415 	}
416 	if (root) {
417 		iget_data.fid.vnode = 1;
418 		iget_data.fid.unique = 1;
419 	} else {
420 		iget_data.fid.vnode = atomic_inc_return(&afs_autocell_ino);
421 		iget_data.fid.unique = 0;
422 	}
423 
424 	inode = iget5_locked(sb, iget_data.fid.vnode,
425 			     afs_iget5_pseudo_dir_test, afs_iget5_set,
426 			     &iget_data);
427 	if (!inode) {
428 		_leave(" = -ENOMEM");
429 		return ERR_PTR(-ENOMEM);
430 	}
431 
432 	_debug("GOT INODE %p { ino=%lu, vl=%llx, vn=%llx, u=%x }",
433 	       inode, inode->i_ino, iget_data.fid.vid, iget_data.fid.vnode,
434 	       iget_data.fid.unique);
435 
436 	vnode = AFS_FS_I(inode);
437 
438 	/* there shouldn't be an existing inode */
439 	BUG_ON(!(inode->i_state & I_NEW));
440 
441 	inode->i_size		= 0;
442 	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
443 	if (root) {
444 		inode->i_op	= &afs_dynroot_inode_operations;
445 		inode->i_fop	= &simple_dir_operations;
446 	} else {
447 		inode->i_op	= &afs_autocell_inode_operations;
448 	}
449 	set_nlink(inode, 2);
450 	inode->i_uid		= GLOBAL_ROOT_UID;
451 	inode->i_gid		= GLOBAL_ROOT_GID;
452 	inode->i_ctime = inode->i_atime = inode->i_mtime = current_time(inode);
453 	inode->i_blocks		= 0;
454 	inode_set_iversion_raw(inode, 0);
455 	inode->i_generation	= 0;
456 
457 	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
458 	if (!root) {
459 		set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
460 		inode->i_flags |= S_AUTOMOUNT;
461 	}
462 
463 	inode->i_flags |= S_NOATIME;
464 	unlock_new_inode(inode);
465 	_leave(" = %p", inode);
466 	return inode;
467 }
468 
469 /*
470  * Get a cache cookie for an inode.
471  */
472 static void afs_get_inode_cache(struct afs_vnode *vnode)
473 {
474 #ifdef CONFIG_AFS_FSCACHE
475 	struct {
476 		u32 vnode_id;
477 		u32 unique;
478 		u32 vnode_id_ext[2];	/* Allow for a 96-bit key */
479 	} __packed key;
480 	struct afs_vnode_cache_aux aux;
481 
482 	if (vnode->status.type == AFS_FTYPE_DIR) {
483 		vnode->cache = NULL;
484 		return;
485 	}
486 
487 	key.vnode_id		= vnode->fid.vnode;
488 	key.unique		= vnode->fid.unique;
489 	key.vnode_id_ext[0]	= vnode->fid.vnode >> 32;
490 	key.vnode_id_ext[1]	= vnode->fid.vnode_hi;
491 	aux.data_version	= vnode->status.data_version;
492 
493 	vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
494 					      &afs_vnode_cache_index_def,
495 					      &key, sizeof(key),
496 					      &aux, sizeof(aux),
497 					      vnode, vnode->status.size, true);
498 #endif
499 }
500 
501 /*
502  * inode retrieval
503  */
504 struct inode *afs_iget(struct super_block *sb, struct key *key,
505 		       struct afs_iget_data *iget_data,
506 		       struct afs_status_cb *scb,
507 		       struct afs_cb_interest *cbi,
508 		       struct afs_vnode *parent_vnode)
509 {
510 	struct afs_super_info *as;
511 	struct afs_vnode *vnode;
512 	struct afs_fid *fid = &iget_data->fid;
513 	struct inode *inode;
514 	int ret;
515 
516 	_enter(",{%llx:%llu.%u},,", fid->vid, fid->vnode, fid->unique);
517 
518 	as = sb->s_fs_info;
519 	iget_data->volume = as->volume;
520 
521 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
522 			     iget_data);
523 	if (!inode) {
524 		_leave(" = -ENOMEM");
525 		return ERR_PTR(-ENOMEM);
526 	}
527 
528 	_debug("GOT INODE %p { vl=%llx vn=%llx, u=%x }",
529 	       inode, fid->vid, fid->vnode, fid->unique);
530 
531 	vnode = AFS_FS_I(inode);
532 
533 	/* deal with an existing inode */
534 	if (!(inode->i_state & I_NEW)) {
535 		_leave(" = %p", inode);
536 		return inode;
537 	}
538 
539 	if (!scb) {
540 		/* it's a remotely extant inode */
541 		ret = afs_fetch_status(vnode, key, true, NULL);
542 		if (ret < 0)
543 			goto bad_inode;
544 	} else {
545 		ret = afs_inode_init_from_status(vnode, key, cbi, parent_vnode,
546 						 scb);
547 		if (ret < 0)
548 			goto bad_inode;
549 	}
550 
551 	afs_get_inode_cache(vnode);
552 
553 	/* success */
554 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
555 	inode->i_flags |= S_NOATIME;
556 	unlock_new_inode(inode);
557 	_leave(" = %p", inode);
558 	return inode;
559 
560 	/* failure */
561 bad_inode:
562 	iget_failed(inode);
563 	_leave(" = %d [bad]", ret);
564 	return ERR_PTR(ret);
565 }
566 
567 /*
568  * mark the data attached to an inode as obsolete due to a write on the server
569  * - might also want to ditch all the outstanding writes and dirty pages
570  */
571 void afs_zap_data(struct afs_vnode *vnode)
572 {
573 	_enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);
574 
575 #ifdef CONFIG_AFS_FSCACHE
576 	fscache_invalidate(vnode->cache);
577 #endif
578 
579 	/* nuke all the non-dirty pages that aren't locked, mapped or being
580 	 * written back in a regular file and completely discard the pages in a
581 	 * directory or symlink */
582 	if (S_ISREG(vnode->vfs_inode.i_mode))
583 		invalidate_remote_inode(&vnode->vfs_inode);
584 	else
585 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
586 }
587 
588 /*
589  * Check the validity of a vnode/inode.
590  */
591 bool afs_check_validity(struct afs_vnode *vnode)
592 {
593 	struct afs_cb_interest *cbi;
594 	struct afs_server *server;
595 	struct afs_volume *volume = vnode->volume;
596 	enum afs_cb_break_reason need_clear = afs_cb_break_no_break;
597 	time64_t now = ktime_get_real_seconds();
598 	bool valid;
599 	unsigned int cb_break, cb_s_break, cb_v_break;
600 	int seq = 0;
601 
602 	do {
603 		read_seqbegin_or_lock(&vnode->cb_lock, &seq);
604 		cb_v_break = READ_ONCE(volume->cb_v_break);
605 		cb_break = vnode->cb_break;
606 
607 		if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
608 			cbi = rcu_dereference(vnode->cb_interest);
609 			server = rcu_dereference(cbi->server);
610 			cb_s_break = READ_ONCE(server->cb_s_break);
611 
612 			if (vnode->cb_s_break != cb_s_break ||
613 			    vnode->cb_v_break != cb_v_break) {
614 				vnode->cb_s_break = cb_s_break;
615 				vnode->cb_v_break = cb_v_break;
616 				need_clear = afs_cb_break_for_vsbreak;
617 				valid = false;
618 			} else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
619 				need_clear = afs_cb_break_for_zap;
620 				valid = false;
621 			} else if (vnode->cb_expires_at - 10 <= now) {
622 				need_clear = afs_cb_break_for_lapsed;
623 				valid = false;
624 			} else {
625 				valid = true;
626 			}
627 		} else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
628 			valid = true;
629 		} else {
630 			vnode->cb_v_break = cb_v_break;
631 			valid = false;
632 		}
633 
634 	} while (need_seqretry(&vnode->cb_lock, seq));
635 
636 	done_seqretry(&vnode->cb_lock, seq);
637 
638 	if (need_clear != afs_cb_break_no_break) {
639 		write_seqlock(&vnode->cb_lock);
640 		if (cb_break == vnode->cb_break)
641 			__afs_break_callback(vnode, need_clear);
642 		else
643 			trace_afs_cb_miss(&vnode->fid, need_clear);
644 		write_sequnlock(&vnode->cb_lock);
645 		valid = false;
646 	}
647 
648 	return valid;
649 }
650 
651 /*
652  * validate a vnode/inode
653  * - there are several things we need to check
654  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
655  *     symlink)
656  *   - parent dir metadata changed (security changes)
657  *   - dentry data changed (write, truncate)
658  *   - dentry metadata changed (security changes)
659  */
660 int afs_validate(struct afs_vnode *vnode, struct key *key)
661 {
662 	bool valid;
663 	int ret;
664 
665 	_enter("{v={%llx:%llu} fl=%lx},%x",
666 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
667 	       key_serial(key));
668 
669 	rcu_read_lock();
670 	valid = afs_check_validity(vnode);
671 	rcu_read_unlock();
672 
673 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
674 		clear_nlink(&vnode->vfs_inode);
675 
676 	if (valid)
677 		goto valid;
678 
679 	down_write(&vnode->validate_lock);
680 
681 	/* if the promise has expired, we need to check the server again to get
682 	 * a new promise - note that if the (parent) directory's metadata was
683 	 * changed then the security may be different and we may no longer have
684 	 * access */
685 	if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
686 		_debug("not promised");
687 		ret = afs_fetch_status(vnode, key, false, NULL);
688 		if (ret < 0) {
689 			if (ret == -ENOENT) {
690 				set_bit(AFS_VNODE_DELETED, &vnode->flags);
691 				ret = -ESTALE;
692 			}
693 			goto error_unlock;
694 		}
695 		_debug("new promise [fl=%lx]", vnode->flags);
696 	}
697 
698 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
699 		_debug("file already deleted");
700 		ret = -ESTALE;
701 		goto error_unlock;
702 	}
703 
704 	/* if the vnode's data version number changed then its contents are
705 	 * different */
706 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
707 		afs_zap_data(vnode);
708 	up_write(&vnode->validate_lock);
709 valid:
710 	_leave(" = 0");
711 	return 0;
712 
713 error_unlock:
714 	up_write(&vnode->validate_lock);
715 	_leave(" = %d", ret);
716 	return ret;
717 }
718 
719 /*
720  * read the attributes of an inode
721  */
722 int afs_getattr(const struct path *path, struct kstat *stat,
723 		u32 request_mask, unsigned int query_flags)
724 {
725 	struct inode *inode = d_inode(path->dentry);
726 	struct afs_vnode *vnode = AFS_FS_I(inode);
727 	int seq = 0;
728 
729 	_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
730 
731 	do {
732 		read_seqbegin_or_lock(&vnode->cb_lock, &seq);
733 		generic_fillattr(inode, stat);
734 	} while (need_seqretry(&vnode->cb_lock, seq));
735 
736 	done_seqretry(&vnode->cb_lock, seq);
737 	return 0;
738 }
739 
740 /*
741  * discard an AFS inode
742  */
743 int afs_drop_inode(struct inode *inode)
744 {
745 	_enter("");
746 
747 	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
748 		return generic_delete_inode(inode);
749 	else
750 		return generic_drop_inode(inode);
751 }
752 
753 /*
754  * clear an AFS inode
755  */
756 void afs_evict_inode(struct inode *inode)
757 {
758 	struct afs_cb_interest *cbi;
759 	struct afs_vnode *vnode;
760 
761 	vnode = AFS_FS_I(inode);
762 
763 	_enter("{%llx:%llu.%d}",
764 	       vnode->fid.vid,
765 	       vnode->fid.vnode,
766 	       vnode->fid.unique);
767 
768 	_debug("CLEAR INODE %p", inode);
769 
770 	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
771 
772 	truncate_inode_pages_final(&inode->i_data);
773 	clear_inode(inode);
774 
775 	write_seqlock(&vnode->cb_lock);
776 	cbi = rcu_dereference_protected(vnode->cb_interest,
777 					lockdep_is_held(&vnode->cb_lock.lock));
778 	if (cbi) {
779 		afs_put_cb_interest(afs_i2net(inode), cbi);
780 		rcu_assign_pointer(vnode->cb_interest, NULL);
781 	}
782 	write_sequnlock(&vnode->cb_lock);
783 
784 	while (!list_empty(&vnode->wb_keys)) {
785 		struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next,
786 						    struct afs_wb_key, vnode_link);
787 		list_del(&wbk->vnode_link);
788 		afs_put_wb_key(wbk);
789 	}
790 
791 #ifdef CONFIG_AFS_FSCACHE
792 	{
793 		struct afs_vnode_cache_aux aux;
794 
795 		aux.data_version = vnode->status.data_version;
796 		fscache_relinquish_cookie(vnode->cache, &aux,
797 					  test_bit(AFS_VNODE_DELETED, &vnode->flags));
798 		vnode->cache = NULL;
799 	}
800 #endif
801 
802 	afs_prune_wb_keys(vnode);
803 	afs_put_permits(rcu_access_pointer(vnode->permit_cache));
804 	key_put(vnode->silly_key);
805 	vnode->silly_key = NULL;
806 	key_put(vnode->lock_key);
807 	vnode->lock_key = NULL;
808 	_leave("");
809 }
810 
811 /*
812  * set the attributes of an inode
813  */
814 int afs_setattr(struct dentry *dentry, struct iattr *attr)
815 {
816 	struct afs_fs_cursor fc;
817 	struct afs_status_cb *scb;
818 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
819 	struct key *key;
820 	int ret = -ENOMEM;
821 
822 	_enter("{%llx:%llu},{n=%pd},%x",
823 	       vnode->fid.vid, vnode->fid.vnode, dentry,
824 	       attr->ia_valid);
825 
826 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
827 				ATTR_MTIME))) {
828 		_leave(" = 0 [unsupported]");
829 		return 0;
830 	}
831 
832 	scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL);
833 	if (!scb)
834 		goto error;
835 
836 	/* flush any dirty data outstanding on a regular file */
837 	if (S_ISREG(vnode->vfs_inode.i_mode))
838 		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
839 
840 	if (attr->ia_valid & ATTR_FILE) {
841 		key = afs_file_key(attr->ia_file);
842 	} else {
843 		key = afs_request_key(vnode->volume->cell);
844 		if (IS_ERR(key)) {
845 			ret = PTR_ERR(key);
846 			goto error_scb;
847 		}
848 	}
849 
850 	ret = -ERESTARTSYS;
851 	if (afs_begin_vnode_operation(&fc, vnode, key, false)) {
852 		afs_dataversion_t data_version = vnode->status.data_version;
853 
854 		if (attr->ia_valid & ATTR_SIZE)
855 			data_version++;
856 
857 		while (afs_select_fileserver(&fc)) {
858 			fc.cb_break = afs_calc_vnode_cb_break(vnode);
859 			afs_fs_setattr(&fc, attr, scb);
860 		}
861 
862 		afs_check_for_remote_deletion(&fc, vnode);
863 		afs_vnode_commit_status(&fc, vnode, fc.cb_break,
864 					&data_version, scb);
865 		ret = afs_end_vnode_operation(&fc);
866 	}
867 
868 	if (!(attr->ia_valid & ATTR_FILE))
869 		key_put(key);
870 
871 error_scb:
872 	kfree(scb);
873 error:
874 	_leave(" = %d", ret);
875 	return ret;
876 }
877