xref: /openbmc/linux/fs/afs/inode.c (revision 5a244f48) 
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 "internal.h"
25 
26 struct afs_iget_data {
27 	struct afs_fid		fid;
28 	struct afs_volume	*volume;	/* volume on which resides */
29 };
30 
31 static const struct inode_operations afs_symlink_inode_operations = {
32 	.get_link	= page_get_link,
33 	.listxattr	= afs_listxattr,
34 };
35 
36 /*
37  * map the AFS file status to the inode member variables
38  */
39 static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
40 {
41 	struct inode *inode = AFS_VNODE_TO_I(vnode);
42 
43 	_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
44 	       vnode->status.type,
45 	       vnode->status.nlink,
46 	       (unsigned long long) vnode->status.size,
47 	       vnode->status.data_version,
48 	       vnode->status.mode);
49 
50 	switch (vnode->status.type) {
51 	case AFS_FTYPE_FILE:
52 		inode->i_mode	= S_IFREG | vnode->status.mode;
53 		inode->i_op	= &afs_file_inode_operations;
54 		inode->i_fop	= &afs_file_operations;
55 		break;
56 	case AFS_FTYPE_DIR:
57 		inode->i_mode	= S_IFDIR | vnode->status.mode;
58 		inode->i_op	= &afs_dir_inode_operations;
59 		inode->i_fop	= &afs_dir_file_operations;
60 		break;
61 	case AFS_FTYPE_SYMLINK:
62 		/* Symlinks with a mode of 0644 are actually mountpoints. */
63 		if ((vnode->status.mode & 0777) == 0644) {
64 			inode->i_flags |= S_AUTOMOUNT;
65 
66 			spin_lock(&vnode->lock);
67 			set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
68 			spin_unlock(&vnode->lock);
69 
70 			inode->i_mode	= S_IFDIR | 0555;
71 			inode->i_op	= &afs_mntpt_inode_operations;
72 			inode->i_fop	= &afs_mntpt_file_operations;
73 		} else {
74 			inode->i_mode	= S_IFLNK | vnode->status.mode;
75 			inode->i_op	= &afs_symlink_inode_operations;
76 		}
77 		inode_nohighmem(inode);
78 		break;
79 	default:
80 		printk("kAFS: AFS vnode with undefined type\n");
81 		return -EBADMSG;
82 	}
83 
84 #ifdef CONFIG_AFS_FSCACHE
85 	if (vnode->status.size != inode->i_size)
86 		fscache_attr_changed(vnode->cache);
87 #endif
88 
89 	set_nlink(inode, vnode->status.nlink);
90 	inode->i_uid		= vnode->status.owner;
91 	inode->i_gid            = vnode->status.group;
92 	inode->i_size		= vnode->status.size;
93 	inode->i_ctime.tv_sec	= vnode->status.mtime_client;
94 	inode->i_ctime.tv_nsec	= 0;
95 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
96 	inode->i_blocks		= 0;
97 	inode->i_generation	= vnode->fid.unique;
98 	inode->i_version	= vnode->status.data_version;
99 	inode->i_mapping->a_ops	= &afs_fs_aops;
100 	return 0;
101 }
102 
103 /*
104  * iget5() comparator
105  */
106 static int afs_iget5_test(struct inode *inode, void *opaque)
107 {
108 	struct afs_iget_data *data = opaque;
109 
110 	return inode->i_ino == data->fid.vnode &&
111 		inode->i_generation == data->fid.unique;
112 }
113 
114 /*
115  * iget5() comparator for inode created by autocell operations
116  *
117  * These pseudo inodes don't match anything.
118  */
119 static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
120 {
121 	return 0;
122 }
123 
124 /*
125  * iget5() inode initialiser
126  */
127 static int afs_iget5_set(struct inode *inode, void *opaque)
128 {
129 	struct afs_iget_data *data = opaque;
130 	struct afs_vnode *vnode = AFS_FS_I(inode);
131 
132 	inode->i_ino = data->fid.vnode;
133 	inode->i_generation = data->fid.unique;
134 	vnode->fid = data->fid;
135 	vnode->volume = data->volume;
136 
137 	return 0;
138 }
139 
140 /*
141  * inode retrieval for autocell
142  */
143 struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
144 				int namesz, struct key *key)
145 {
146 	struct afs_iget_data data;
147 	struct afs_super_info *as;
148 	struct afs_vnode *vnode;
149 	struct super_block *sb;
150 	struct inode *inode;
151 	static atomic_t afs_autocell_ino;
152 
153 	_enter("{%x:%u},%*.*s,",
154 	       AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
155 	       namesz, namesz, dev_name ?: "");
156 
157 	sb = dir->i_sb;
158 	as = sb->s_fs_info;
159 	data.volume = as->volume;
160 	data.fid.vid = as->volume->vid;
161 	data.fid.unique = 0;
162 	data.fid.vnode = 0;
163 
164 	inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
165 			     afs_iget5_autocell_test, afs_iget5_set,
166 			     &data);
167 	if (!inode) {
168 		_leave(" = -ENOMEM");
169 		return ERR_PTR(-ENOMEM);
170 	}
171 
172 	_debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
173 	       inode, inode->i_ino, data.fid.vid, data.fid.vnode,
174 	       data.fid.unique);
175 
176 	vnode = AFS_FS_I(inode);
177 
178 	/* there shouldn't be an existing inode */
179 	BUG_ON(!(inode->i_state & I_NEW));
180 
181 	inode->i_size		= 0;
182 	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
183 	inode->i_op		= &afs_autocell_inode_operations;
184 	set_nlink(inode, 2);
185 	inode->i_uid		= GLOBAL_ROOT_UID;
186 	inode->i_gid		= GLOBAL_ROOT_GID;
187 	inode->i_ctime.tv_sec	= get_seconds();
188 	inode->i_ctime.tv_nsec	= 0;
189 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
190 	inode->i_blocks		= 0;
191 	inode->i_version	= 0;
192 	inode->i_generation	= 0;
193 
194 	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
195 	set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
196 	inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
197 	unlock_new_inode(inode);
198 	_leave(" = %p", inode);
199 	return inode;
200 }
201 
202 /*
203  * inode retrieval
204  */
205 struct inode *afs_iget(struct super_block *sb, struct key *key,
206 		       struct afs_fid *fid, struct afs_file_status *status,
207 		       struct afs_callback *cb)
208 {
209 	struct afs_iget_data data = { .fid = *fid };
210 	struct afs_super_info *as;
211 	struct afs_vnode *vnode;
212 	struct inode *inode;
213 	int ret;
214 
215 	_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
216 
217 	as = sb->s_fs_info;
218 	data.volume = as->volume;
219 
220 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
221 			     &data);
222 	if (!inode) {
223 		_leave(" = -ENOMEM");
224 		return ERR_PTR(-ENOMEM);
225 	}
226 
227 	_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
228 	       inode, fid->vid, fid->vnode, fid->unique);
229 
230 	vnode = AFS_FS_I(inode);
231 
232 	/* deal with an existing inode */
233 	if (!(inode->i_state & I_NEW)) {
234 		_leave(" = %p", inode);
235 		return inode;
236 	}
237 
238 	if (!status) {
239 		/* it's a remotely extant inode */
240 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
241 		ret = afs_vnode_fetch_status(vnode, NULL, key);
242 		if (ret < 0)
243 			goto bad_inode;
244 	} else {
245 		/* it's an inode we just created */
246 		memcpy(&vnode->status, status, sizeof(vnode->status));
247 
248 		if (!cb) {
249 			/* it's a symlink we just created (the fileserver
250 			 * didn't give us a callback) */
251 			vnode->cb_version = 0;
252 			vnode->cb_expiry = 0;
253 			vnode->cb_type = 0;
254 			vnode->cb_expires = ktime_get_real_seconds();
255 		} else {
256 			vnode->cb_version = cb->version;
257 			vnode->cb_expiry = cb->expiry;
258 			vnode->cb_type = cb->type;
259 			vnode->cb_expires = vnode->cb_expiry +
260 				ktime_get_real_seconds();
261 		}
262 	}
263 
264 	/* set up caching before mapping the status, as map-status reads the
265 	 * first page of symlinks to see if they're really mountpoints */
266 	inode->i_size = vnode->status.size;
267 #ifdef CONFIG_AFS_FSCACHE
268 	vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
269 					      &afs_vnode_cache_index_def,
270 					      vnode, true);
271 #endif
272 
273 	ret = afs_inode_map_status(vnode, key);
274 	if (ret < 0)
275 		goto bad_inode;
276 
277 	/* success */
278 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
279 	inode->i_flags |= S_NOATIME;
280 	unlock_new_inode(inode);
281 	_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
282 	return inode;
283 
284 	/* failure */
285 bad_inode:
286 #ifdef CONFIG_AFS_FSCACHE
287 	fscache_relinquish_cookie(vnode->cache, 0);
288 	vnode->cache = NULL;
289 #endif
290 	iget_failed(inode);
291 	_leave(" = %d [bad]", ret);
292 	return ERR_PTR(ret);
293 }
294 
295 /*
296  * mark the data attached to an inode as obsolete due to a write on the server
297  * - might also want to ditch all the outstanding writes and dirty pages
298  */
299 void afs_zap_data(struct afs_vnode *vnode)
300 {
301 	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
302 
303 	/* nuke all the non-dirty pages that aren't locked, mapped or being
304 	 * written back in a regular file and completely discard the pages in a
305 	 * directory or symlink */
306 	if (S_ISREG(vnode->vfs_inode.i_mode))
307 		invalidate_remote_inode(&vnode->vfs_inode);
308 	else
309 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
310 }
311 
312 /*
313  * validate a vnode/inode
314  * - there are several things we need to check
315  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
316  *     symlink)
317  *   - parent dir metadata changed (security changes)
318  *   - dentry data changed (write, truncate)
319  *   - dentry metadata changed (security changes)
320  */
321 int afs_validate(struct afs_vnode *vnode, struct key *key)
322 {
323 	int ret;
324 
325 	_enter("{v={%x:%u} fl=%lx},%x",
326 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
327 	       key_serial(key));
328 
329 	if (vnode->cb_promised &&
330 	    !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
331 	    !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
332 	    !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
333 		if (vnode->cb_expires < ktime_get_real_seconds() + 10) {
334 			_debug("callback expired");
335 			set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
336 		} else {
337 			goto valid;
338 		}
339 	}
340 
341 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
342 		goto valid;
343 
344 	mutex_lock(&vnode->validate_lock);
345 
346 	/* if the promise has expired, we need to check the server again to get
347 	 * a new promise - note that if the (parent) directory's metadata was
348 	 * changed then the security may be different and we may no longer have
349 	 * access */
350 	if (!vnode->cb_promised ||
351 	    test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
352 		_debug("not promised");
353 		ret = afs_vnode_fetch_status(vnode, NULL, key);
354 		if (ret < 0)
355 			goto error_unlock;
356 		_debug("new promise [fl=%lx]", vnode->flags);
357 	}
358 
359 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
360 		_debug("file already deleted");
361 		ret = -ESTALE;
362 		goto error_unlock;
363 	}
364 
365 	/* if the vnode's data version number changed then its contents are
366 	 * different */
367 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
368 		afs_zap_data(vnode);
369 
370 	clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
371 	mutex_unlock(&vnode->validate_lock);
372 valid:
373 	_leave(" = 0");
374 	return 0;
375 
376 error_unlock:
377 	mutex_unlock(&vnode->validate_lock);
378 	_leave(" = %d", ret);
379 	return ret;
380 }
381 
382 /*
383  * read the attributes of an inode
384  */
385 int afs_getattr(const struct path *path, struct kstat *stat,
386 		u32 request_mask, unsigned int query_flags)
387 {
388 	struct inode *inode = d_inode(path->dentry);
389 
390 	_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
391 
392 	generic_fillattr(inode, stat);
393 	return 0;
394 }
395 
396 /*
397  * discard an AFS inode
398  */
399 int afs_drop_inode(struct inode *inode)
400 {
401 	_enter("");
402 
403 	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
404 		return generic_delete_inode(inode);
405 	else
406 		return generic_drop_inode(inode);
407 }
408 
409 /*
410  * clear an AFS inode
411  */
412 void afs_evict_inode(struct inode *inode)
413 {
414 	struct afs_permits *permits;
415 	struct afs_vnode *vnode;
416 
417 	vnode = AFS_FS_I(inode);
418 
419 	_enter("{%x:%u.%d} v=%u x=%u t=%u }",
420 	       vnode->fid.vid,
421 	       vnode->fid.vnode,
422 	       vnode->fid.unique,
423 	       vnode->cb_version,
424 	       vnode->cb_expiry,
425 	       vnode->cb_type);
426 
427 	_debug("CLEAR INODE %p", inode);
428 
429 	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
430 
431 	truncate_inode_pages_final(&inode->i_data);
432 	clear_inode(inode);
433 
434 	afs_give_up_callback(vnode);
435 
436 	if (vnode->server) {
437 		spin_lock(&vnode->server->fs_lock);
438 		rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
439 		spin_unlock(&vnode->server->fs_lock);
440 		afs_put_server(vnode->server);
441 		vnode->server = NULL;
442 	}
443 
444 	ASSERT(list_empty(&vnode->writebacks));
445 	ASSERT(!vnode->cb_promised);
446 
447 #ifdef CONFIG_AFS_FSCACHE
448 	fscache_relinquish_cookie(vnode->cache, 0);
449 	vnode->cache = NULL;
450 #endif
451 
452 	mutex_lock(&vnode->permits_lock);
453 	permits = vnode->permits;
454 	RCU_INIT_POINTER(vnode->permits, NULL);
455 	mutex_unlock(&vnode->permits_lock);
456 	if (permits)
457 		call_rcu(&permits->rcu, afs_zap_permits);
458 
459 	_leave("");
460 }
461 
462 /*
463  * set the attributes of an inode
464  */
465 int afs_setattr(struct dentry *dentry, struct iattr *attr)
466 {
467 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
468 	struct key *key;
469 	int ret;
470 
471 	_enter("{%x:%u},{n=%pd},%x",
472 	       vnode->fid.vid, vnode->fid.vnode, dentry,
473 	       attr->ia_valid);
474 
475 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
476 				ATTR_MTIME))) {
477 		_leave(" = 0 [unsupported]");
478 		return 0;
479 	}
480 
481 	/* flush any dirty data outstanding on a regular file */
482 	if (S_ISREG(vnode->vfs_inode.i_mode)) {
483 		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
484 		afs_writeback_all(vnode);
485 	}
486 
487 	if (attr->ia_valid & ATTR_FILE) {
488 		key = attr->ia_file->private_data;
489 	} else {
490 		key = afs_request_key(vnode->volume->cell);
491 		if (IS_ERR(key)) {
492 			ret = PTR_ERR(key);
493 			goto error;
494 		}
495 	}
496 
497 	ret = afs_vnode_setattr(vnode, key, attr);
498 	if (!(attr->ia_valid & ATTR_FILE))
499 		key_put(key);
500 
501 error:
502 	_leave(" = %d", ret);
503 	return ret;
504 }
505