xref: /openbmc/linux/fs/afs/inode.c (revision 752beb5e) 
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 
27 static const struct inode_operations afs_symlink_inode_operations = {
28 	.get_link	= page_get_link,
29 	.listxattr	= afs_listxattr,
30 };
31 
32 static noinline void dump_vnode(struct afs_vnode *vnode, struct afs_vnode *parent_vnode)
33 {
34 	static unsigned long once_only;
35 
36 	pr_warn("kAFS: AFS vnode with undefined type %u\n",
37 		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  * Initialise an inode from the vnode status.
59  */
60 static int afs_inode_init_from_status(struct afs_vnode *vnode, struct key *key,
61 				      struct afs_vnode *parent_vnode)
62 {
63 	struct inode *inode = AFS_VNODE_TO_I(vnode);
64 
65 	_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
66 	       vnode->status.type,
67 	       vnode->status.nlink,
68 	       (unsigned long long) vnode->status.size,
69 	       vnode->status.data_version,
70 	       vnode->status.mode);
71 
72 	read_seqlock_excl(&vnode->cb_lock);
73 
74 	afs_update_inode_from_status(vnode, &vnode->status, NULL,
75 				     AFS_VNODE_NOT_YET_SET);
76 
77 	switch (vnode->status.type) {
78 	case AFS_FTYPE_FILE:
79 		inode->i_mode	= S_IFREG | vnode->status.mode;
80 		inode->i_op	= &afs_file_inode_operations;
81 		inode->i_fop	= &afs_file_operations;
82 		inode->i_mapping->a_ops	= &afs_fs_aops;
83 		break;
84 	case AFS_FTYPE_DIR:
85 		inode->i_mode	= S_IFDIR | vnode->status.mode;
86 		inode->i_op	= &afs_dir_inode_operations;
87 		inode->i_fop	= &afs_dir_file_operations;
88 		inode->i_mapping->a_ops	= &afs_dir_aops;
89 		break;
90 	case AFS_FTYPE_SYMLINK:
91 		/* Symlinks with a mode of 0644 are actually mountpoints. */
92 		if ((vnode->status.mode & 0777) == 0644) {
93 			inode->i_flags |= S_AUTOMOUNT;
94 
95 			set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
96 
97 			inode->i_mode	= S_IFDIR | 0555;
98 			inode->i_op	= &afs_mntpt_inode_operations;
99 			inode->i_fop	= &afs_mntpt_file_operations;
100 			inode->i_mapping->a_ops	= &afs_fs_aops;
101 		} else {
102 			inode->i_mode	= S_IFLNK | vnode->status.mode;
103 			inode->i_op	= &afs_symlink_inode_operations;
104 			inode->i_mapping->a_ops	= &afs_fs_aops;
105 		}
106 		inode_nohighmem(inode);
107 		break;
108 	default:
109 		dump_vnode(vnode, parent_vnode);
110 		read_sequnlock_excl(&vnode->cb_lock);
111 		return afs_protocol_error(NULL, -EBADMSG, afs_eproto_file_type);
112 	}
113 
114 	/*
115 	 * Estimate 512 bytes  blocks used, rounded up to nearest 1K
116 	 * for consistency with other AFS clients.
117 	 */
118 	inode->i_blocks		= ((i_size_read(inode) + 1023) >> 10) << 1;
119 	vnode->invalid_before	= vnode->status.data_version;
120 
121 	read_sequnlock_excl(&vnode->cb_lock);
122 	return 0;
123 }
124 
125 /*
126  * Fetch file status from the volume.
127  */
128 int afs_fetch_status(struct afs_vnode *vnode, struct key *key, bool new_inode)
129 {
130 	struct afs_fs_cursor fc;
131 	int ret;
132 
133 	_enter("%s,{%llx:%llu.%u,S=%lx}",
134 	       vnode->volume->name,
135 	       vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
136 	       vnode->flags);
137 
138 	ret = -ERESTARTSYS;
139 	if (afs_begin_vnode_operation(&fc, vnode, key)) {
140 		while (afs_select_fileserver(&fc)) {
141 			fc.cb_break = afs_calc_vnode_cb_break(vnode);
142 			afs_fs_fetch_file_status(&fc, NULL, new_inode);
143 		}
144 
145 		afs_check_for_remote_deletion(&fc, fc.vnode);
146 		afs_vnode_commit_status(&fc, vnode, fc.cb_break);
147 		ret = afs_end_vnode_operation(&fc);
148 	}
149 
150 	_leave(" = %d", ret);
151 	return ret;
152 }
153 
154 /*
155  * iget5() comparator
156  */
157 int afs_iget5_test(struct inode *inode, void *opaque)
158 {
159 	struct afs_iget_data *data = opaque;
160 	struct afs_vnode *vnode = AFS_FS_I(inode);
161 
162 	return memcmp(&vnode->fid, &data->fid, sizeof(data->fid)) == 0;
163 }
164 
165 /*
166  * iget5() comparator for inode created by autocell operations
167  *
168  * These pseudo inodes don't match anything.
169  */
170 static int afs_iget5_pseudo_dir_test(struct inode *inode, void *opaque)
171 {
172 	return 0;
173 }
174 
175 /*
176  * iget5() inode initialiser
177  */
178 static int afs_iget5_set(struct inode *inode, void *opaque)
179 {
180 	struct afs_iget_data *data = opaque;
181 	struct afs_vnode *vnode = AFS_FS_I(inode);
182 
183 	vnode->fid = data->fid;
184 	vnode->volume = data->volume;
185 
186 	/* YFS supports 96-bit vnode IDs, but Linux only supports
187 	 * 64-bit inode numbers.
188 	 */
189 	inode->i_ino = data->fid.vnode;
190 	inode->i_generation = data->fid.unique;
191 	return 0;
192 }
193 
194 /*
195  * Create an inode for a dynamic root directory or an autocell dynamic
196  * automount dir.
197  */
198 struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
199 {
200 	struct afs_iget_data data;
201 	struct afs_super_info *as;
202 	struct afs_vnode *vnode;
203 	struct inode *inode;
204 	static atomic_t afs_autocell_ino;
205 
206 	_enter("");
207 
208 	as = sb->s_fs_info;
209 	if (as->volume) {
210 		data.volume = as->volume;
211 		data.fid.vid = as->volume->vid;
212 	}
213 	if (root) {
214 		data.fid.vnode = 1;
215 		data.fid.unique = 1;
216 	} else {
217 		data.fid.vnode = atomic_inc_return(&afs_autocell_ino);
218 		data.fid.unique = 0;
219 	}
220 
221 	inode = iget5_locked(sb, data.fid.vnode,
222 			     afs_iget5_pseudo_dir_test, afs_iget5_set,
223 			     &data);
224 	if (!inode) {
225 		_leave(" = -ENOMEM");
226 		return ERR_PTR(-ENOMEM);
227 	}
228 
229 	_debug("GOT INODE %p { ino=%lu, vl=%llx, vn=%llx, u=%x }",
230 	       inode, inode->i_ino, data.fid.vid, data.fid.vnode,
231 	       data.fid.unique);
232 
233 	vnode = AFS_FS_I(inode);
234 
235 	/* there shouldn't be an existing inode */
236 	BUG_ON(!(inode->i_state & I_NEW));
237 
238 	inode->i_size		= 0;
239 	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
240 	if (root) {
241 		inode->i_op	= &afs_dynroot_inode_operations;
242 		inode->i_fop	= &afs_dynroot_file_operations;
243 	} else {
244 		inode->i_op	= &afs_autocell_inode_operations;
245 	}
246 	set_nlink(inode, 2);
247 	inode->i_uid		= GLOBAL_ROOT_UID;
248 	inode->i_gid		= GLOBAL_ROOT_GID;
249 	inode->i_ctime = inode->i_atime = inode->i_mtime = current_time(inode);
250 	inode->i_blocks		= 0;
251 	inode_set_iversion_raw(inode, 0);
252 	inode->i_generation	= 0;
253 
254 	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
255 	if (!root) {
256 		set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
257 		inode->i_flags |= S_AUTOMOUNT;
258 	}
259 
260 	inode->i_flags |= S_NOATIME;
261 	unlock_new_inode(inode);
262 	_leave(" = %p", inode);
263 	return inode;
264 }
265 
266 /*
267  * Get a cache cookie for an inode.
268  */
269 static void afs_get_inode_cache(struct afs_vnode *vnode)
270 {
271 #ifdef CONFIG_AFS_FSCACHE
272 	struct {
273 		u32 vnode_id;
274 		u32 unique;
275 		u32 vnode_id_ext[2];	/* Allow for a 96-bit key */
276 	} __packed key;
277 	struct afs_vnode_cache_aux aux;
278 
279 	if (vnode->status.type == AFS_FTYPE_DIR) {
280 		vnode->cache = NULL;
281 		return;
282 	}
283 
284 	key.vnode_id		= vnode->fid.vnode;
285 	key.unique		= vnode->fid.unique;
286 	key.vnode_id_ext[0]	= vnode->fid.vnode >> 32;
287 	key.vnode_id_ext[1]	= vnode->fid.vnode_hi;
288 	aux.data_version	= vnode->status.data_version;
289 
290 	vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
291 					      &afs_vnode_cache_index_def,
292 					      &key, sizeof(key),
293 					      &aux, sizeof(aux),
294 					      vnode, vnode->status.size, true);
295 #endif
296 }
297 
298 /*
299  * inode retrieval
300  */
301 struct inode *afs_iget(struct super_block *sb, struct key *key,
302 		       struct afs_fid *fid, struct afs_file_status *status,
303 		       struct afs_callback *cb, struct afs_cb_interest *cbi,
304 		       struct afs_vnode *parent_vnode)
305 {
306 	struct afs_iget_data data = { .fid = *fid };
307 	struct afs_super_info *as;
308 	struct afs_vnode *vnode;
309 	struct inode *inode;
310 	int ret;
311 
312 	_enter(",{%llx:%llu.%u},,", fid->vid, fid->vnode, fid->unique);
313 
314 	as = sb->s_fs_info;
315 	data.volume = as->volume;
316 
317 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
318 			     &data);
319 	if (!inode) {
320 		_leave(" = -ENOMEM");
321 		return ERR_PTR(-ENOMEM);
322 	}
323 
324 	_debug("GOT INODE %p { vl=%llx vn=%llx, u=%x }",
325 	       inode, fid->vid, fid->vnode, fid->unique);
326 
327 	vnode = AFS_FS_I(inode);
328 
329 	/* deal with an existing inode */
330 	if (!(inode->i_state & I_NEW)) {
331 		_leave(" = %p", inode);
332 		return inode;
333 	}
334 
335 	if (!status) {
336 		/* it's a remotely extant inode */
337 		ret = afs_fetch_status(vnode, key, true);
338 		if (ret < 0)
339 			goto bad_inode;
340 	} else {
341 		/* it's an inode we just created */
342 		memcpy(&vnode->status, status, sizeof(vnode->status));
343 
344 		if (!cb) {
345 			/* it's a symlink we just created (the fileserver
346 			 * didn't give us a callback) */
347 			vnode->cb_version = 0;
348 			vnode->cb_type = 0;
349 			vnode->cb_expires_at = ktime_get();
350 		} else {
351 			vnode->cb_version = cb->version;
352 			vnode->cb_type = cb->type;
353 			vnode->cb_expires_at = cb->expires_at;
354 			vnode->cb_interest = afs_get_cb_interest(cbi);
355 			set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
356 		}
357 
358 		vnode->cb_expires_at += ktime_get_real_seconds();
359 	}
360 
361 	ret = afs_inode_init_from_status(vnode, key, parent_vnode);
362 	if (ret < 0)
363 		goto bad_inode;
364 
365 	afs_get_inode_cache(vnode);
366 
367 	/* success */
368 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
369 	inode->i_flags |= S_NOATIME;
370 	unlock_new_inode(inode);
371 	_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
372 	return inode;
373 
374 	/* failure */
375 bad_inode:
376 	iget_failed(inode);
377 	_leave(" = %d [bad]", ret);
378 	return ERR_PTR(ret);
379 }
380 
381 /*
382  * mark the data attached to an inode as obsolete due to a write on the server
383  * - might also want to ditch all the outstanding writes and dirty pages
384  */
385 void afs_zap_data(struct afs_vnode *vnode)
386 {
387 	_enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);
388 
389 #ifdef CONFIG_AFS_FSCACHE
390 	fscache_invalidate(vnode->cache);
391 #endif
392 
393 	/* nuke all the non-dirty pages that aren't locked, mapped or being
394 	 * written back in a regular file and completely discard the pages in a
395 	 * directory or symlink */
396 	if (S_ISREG(vnode->vfs_inode.i_mode))
397 		invalidate_remote_inode(&vnode->vfs_inode);
398 	else
399 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
400 }
401 
402 /*
403  * validate a vnode/inode
404  * - there are several things we need to check
405  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
406  *     symlink)
407  *   - parent dir metadata changed (security changes)
408  *   - dentry data changed (write, truncate)
409  *   - dentry metadata changed (security changes)
410  */
411 int afs_validate(struct afs_vnode *vnode, struct key *key)
412 {
413 	time64_t now = ktime_get_real_seconds();
414 	bool valid;
415 	int ret;
416 
417 	_enter("{v={%llx:%llu} fl=%lx},%x",
418 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
419 	       key_serial(key));
420 
421 	/* Quickly check the callback state.  Ideally, we'd use read_seqbegin
422 	 * here, but we have no way to pass the net namespace to the RCU
423 	 * cleanup for the server record.
424 	 */
425 	read_seqlock_excl(&vnode->cb_lock);
426 
427 	if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
428 		if (vnode->cb_s_break != vnode->cb_interest->server->cb_s_break ||
429 		    vnode->cb_v_break != vnode->volume->cb_v_break) {
430 			vnode->cb_s_break = vnode->cb_interest->server->cb_s_break;
431 			vnode->cb_v_break = vnode->volume->cb_v_break;
432 			valid = false;
433 		} else if (vnode->status.type == AFS_FTYPE_DIR &&
434 			   (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags) ||
435 			    vnode->cb_expires_at - 10 <= now)) {
436 			valid = false;
437 		} else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags) ||
438 			   vnode->cb_expires_at - 10 <= now) {
439 			valid = false;
440 		} else {
441 			valid = true;
442 		}
443 	} else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
444 		valid = true;
445 	} else {
446 		vnode->cb_v_break = vnode->volume->cb_v_break;
447 		valid = false;
448 	}
449 
450 	read_sequnlock_excl(&vnode->cb_lock);
451 
452 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
453 		clear_nlink(&vnode->vfs_inode);
454 
455 	if (valid)
456 		goto valid;
457 
458 	down_write(&vnode->validate_lock);
459 
460 	/* if the promise has expired, we need to check the server again to get
461 	 * a new promise - note that if the (parent) directory's metadata was
462 	 * changed then the security may be different and we may no longer have
463 	 * access */
464 	if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
465 		_debug("not promised");
466 		ret = afs_fetch_status(vnode, key, false);
467 		if (ret < 0) {
468 			if (ret == -ENOENT) {
469 				set_bit(AFS_VNODE_DELETED, &vnode->flags);
470 				ret = -ESTALE;
471 			}
472 			goto error_unlock;
473 		}
474 		_debug("new promise [fl=%lx]", vnode->flags);
475 	}
476 
477 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
478 		_debug("file already deleted");
479 		ret = -ESTALE;
480 		goto error_unlock;
481 	}
482 
483 	/* if the vnode's data version number changed then its contents are
484 	 * different */
485 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
486 		afs_zap_data(vnode);
487 	up_write(&vnode->validate_lock);
488 valid:
489 	_leave(" = 0");
490 	return 0;
491 
492 error_unlock:
493 	up_write(&vnode->validate_lock);
494 	_leave(" = %d", ret);
495 	return ret;
496 }
497 
498 /*
499  * read the attributes of an inode
500  */
501 int afs_getattr(const struct path *path, struct kstat *stat,
502 		u32 request_mask, unsigned int query_flags)
503 {
504 	struct inode *inode = d_inode(path->dentry);
505 	struct afs_vnode *vnode = AFS_FS_I(inode);
506 	int seq = 0;
507 
508 	_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
509 
510 	do {
511 		read_seqbegin_or_lock(&vnode->cb_lock, &seq);
512 		generic_fillattr(inode, stat);
513 	} while (need_seqretry(&vnode->cb_lock, seq));
514 
515 	done_seqretry(&vnode->cb_lock, seq);
516 	return 0;
517 }
518 
519 /*
520  * discard an AFS inode
521  */
522 int afs_drop_inode(struct inode *inode)
523 {
524 	_enter("");
525 
526 	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
527 		return generic_delete_inode(inode);
528 	else
529 		return generic_drop_inode(inode);
530 }
531 
532 /*
533  * clear an AFS inode
534  */
535 void afs_evict_inode(struct inode *inode)
536 {
537 	struct afs_vnode *vnode;
538 
539 	vnode = AFS_FS_I(inode);
540 
541 	_enter("{%llx:%llu.%d}",
542 	       vnode->fid.vid,
543 	       vnode->fid.vnode,
544 	       vnode->fid.unique);
545 
546 	_debug("CLEAR INODE %p", inode);
547 
548 	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
549 
550 	truncate_inode_pages_final(&inode->i_data);
551 	clear_inode(inode);
552 
553 	if (vnode->cb_interest) {
554 		afs_put_cb_interest(afs_i2net(inode), vnode->cb_interest);
555 		vnode->cb_interest = NULL;
556 	}
557 
558 	while (!list_empty(&vnode->wb_keys)) {
559 		struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next,
560 						    struct afs_wb_key, vnode_link);
561 		list_del(&wbk->vnode_link);
562 		afs_put_wb_key(wbk);
563 	}
564 
565 #ifdef CONFIG_AFS_FSCACHE
566 	{
567 		struct afs_vnode_cache_aux aux;
568 
569 		aux.data_version = vnode->status.data_version;
570 		fscache_relinquish_cookie(vnode->cache, &aux,
571 					  test_bit(AFS_VNODE_DELETED, &vnode->flags));
572 		vnode->cache = NULL;
573 	}
574 #endif
575 
576 	afs_put_permits(rcu_access_pointer(vnode->permit_cache));
577 	key_put(vnode->silly_key);
578 	vnode->silly_key = NULL;
579 	key_put(vnode->lock_key);
580 	vnode->lock_key = NULL;
581 	_leave("");
582 }
583 
584 /*
585  * set the attributes of an inode
586  */
587 int afs_setattr(struct dentry *dentry, struct iattr *attr)
588 {
589 	struct afs_fs_cursor fc;
590 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
591 	struct key *key;
592 	int ret;
593 
594 	_enter("{%llx:%llu},{n=%pd},%x",
595 	       vnode->fid.vid, vnode->fid.vnode, dentry,
596 	       attr->ia_valid);
597 
598 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
599 				ATTR_MTIME))) {
600 		_leave(" = 0 [unsupported]");
601 		return 0;
602 	}
603 
604 	/* flush any dirty data outstanding on a regular file */
605 	if (S_ISREG(vnode->vfs_inode.i_mode))
606 		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
607 
608 	if (attr->ia_valid & ATTR_FILE) {
609 		key = afs_file_key(attr->ia_file);
610 	} else {
611 		key = afs_request_key(vnode->volume->cell);
612 		if (IS_ERR(key)) {
613 			ret = PTR_ERR(key);
614 			goto error;
615 		}
616 	}
617 
618 	ret = -ERESTARTSYS;
619 	if (afs_begin_vnode_operation(&fc, vnode, key)) {
620 		while (afs_select_fileserver(&fc)) {
621 			fc.cb_break = afs_calc_vnode_cb_break(vnode);
622 			afs_fs_setattr(&fc, attr);
623 		}
624 
625 		afs_check_for_remote_deletion(&fc, fc.vnode);
626 		afs_vnode_commit_status(&fc, vnode, fc.cb_break);
627 		ret = afs_end_vnode_operation(&fc);
628 	}
629 
630 	if (!(attr->ia_valid & ATTR_FILE))
631 		key_put(key);
632 
633 error:
634 	_leave(" = %d", ret);
635 	return ret;
636 }
637