xref: /openbmc/linux/fs/afs/inode.c (revision aac5987a) 
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 /*
32  * map the AFS file status to the inode member variables
33  */
34 static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
35 {
36 	struct inode *inode = AFS_VNODE_TO_I(vnode);
37 
38 	_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
39 	       vnode->status.type,
40 	       vnode->status.nlink,
41 	       (unsigned long long) vnode->status.size,
42 	       vnode->status.data_version,
43 	       vnode->status.mode);
44 
45 	switch (vnode->status.type) {
46 	case AFS_FTYPE_FILE:
47 		inode->i_mode	= S_IFREG | vnode->status.mode;
48 		inode->i_op	= &afs_file_inode_operations;
49 		inode->i_fop	= &afs_file_operations;
50 		break;
51 	case AFS_FTYPE_DIR:
52 		inode->i_mode	= S_IFDIR | vnode->status.mode;
53 		inode->i_op	= &afs_dir_inode_operations;
54 		inode->i_fop	= &afs_dir_file_operations;
55 		break;
56 	case AFS_FTYPE_SYMLINK:
57 		inode->i_mode	= S_IFLNK | vnode->status.mode;
58 		inode->i_op	= &page_symlink_inode_operations;
59 		inode_nohighmem(inode);
60 		break;
61 	default:
62 		printk("kAFS: AFS vnode with undefined type\n");
63 		return -EBADMSG;
64 	}
65 
66 #ifdef CONFIG_AFS_FSCACHE
67 	if (vnode->status.size != inode->i_size)
68 		fscache_attr_changed(vnode->cache);
69 #endif
70 
71 	set_nlink(inode, vnode->status.nlink);
72 	inode->i_uid		= vnode->status.owner;
73 	inode->i_gid		= GLOBAL_ROOT_GID;
74 	inode->i_size		= vnode->status.size;
75 	inode->i_ctime.tv_sec	= vnode->status.mtime_server;
76 	inode->i_ctime.tv_nsec	= 0;
77 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
78 	inode->i_blocks		= 0;
79 	inode->i_generation	= vnode->fid.unique;
80 	inode->i_version	= vnode->status.data_version;
81 	inode->i_mapping->a_ops	= &afs_fs_aops;
82 
83 	/* check to see whether a symbolic link is really a mountpoint */
84 	if (vnode->status.type == AFS_FTYPE_SYMLINK) {
85 		afs_mntpt_check_symlink(vnode, key);
86 
87 		if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
88 			inode->i_mode	= S_IFDIR | vnode->status.mode;
89 			inode->i_op	= &afs_mntpt_inode_operations;
90 			inode->i_fop	= &afs_mntpt_file_operations;
91 		}
92 	}
93 
94 	return 0;
95 }
96 
97 /*
98  * iget5() comparator
99  */
100 static int afs_iget5_test(struct inode *inode, void *opaque)
101 {
102 	struct afs_iget_data *data = opaque;
103 
104 	return inode->i_ino == data->fid.vnode &&
105 		inode->i_generation == data->fid.unique;
106 }
107 
108 /*
109  * iget5() comparator for inode created by autocell operations
110  *
111  * These pseudo inodes don't match anything.
112  */
113 static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
114 {
115 	return 0;
116 }
117 
118 /*
119  * iget5() inode initialiser
120  */
121 static int afs_iget5_set(struct inode *inode, void *opaque)
122 {
123 	struct afs_iget_data *data = opaque;
124 	struct afs_vnode *vnode = AFS_FS_I(inode);
125 
126 	inode->i_ino = data->fid.vnode;
127 	inode->i_generation = data->fid.unique;
128 	vnode->fid = data->fid;
129 	vnode->volume = data->volume;
130 
131 	return 0;
132 }
133 
134 /*
135  * inode retrieval for autocell
136  */
137 struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
138 				int namesz, struct key *key)
139 {
140 	struct afs_iget_data data;
141 	struct afs_super_info *as;
142 	struct afs_vnode *vnode;
143 	struct super_block *sb;
144 	struct inode *inode;
145 	static atomic_t afs_autocell_ino;
146 
147 	_enter("{%x:%u},%*.*s,",
148 	       AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
149 	       namesz, namesz, dev_name ?: "");
150 
151 	sb = dir->i_sb;
152 	as = sb->s_fs_info;
153 	data.volume = as->volume;
154 	data.fid.vid = as->volume->vid;
155 	data.fid.unique = 0;
156 	data.fid.vnode = 0;
157 
158 	inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
159 			     afs_iget5_autocell_test, afs_iget5_set,
160 			     &data);
161 	if (!inode) {
162 		_leave(" = -ENOMEM");
163 		return ERR_PTR(-ENOMEM);
164 	}
165 
166 	_debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
167 	       inode, inode->i_ino, data.fid.vid, data.fid.vnode,
168 	       data.fid.unique);
169 
170 	vnode = AFS_FS_I(inode);
171 
172 	/* there shouldn't be an existing inode */
173 	BUG_ON(!(inode->i_state & I_NEW));
174 
175 	inode->i_size		= 0;
176 	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
177 	inode->i_op		= &afs_autocell_inode_operations;
178 	set_nlink(inode, 2);
179 	inode->i_uid		= GLOBAL_ROOT_UID;
180 	inode->i_gid		= GLOBAL_ROOT_GID;
181 	inode->i_ctime.tv_sec	= get_seconds();
182 	inode->i_ctime.tv_nsec	= 0;
183 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
184 	inode->i_blocks		= 0;
185 	inode->i_version	= 0;
186 	inode->i_generation	= 0;
187 
188 	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
189 	set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
190 	inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
191 	unlock_new_inode(inode);
192 	_leave(" = %p", inode);
193 	return inode;
194 }
195 
196 /*
197  * inode retrieval
198  */
199 struct inode *afs_iget(struct super_block *sb, struct key *key,
200 		       struct afs_fid *fid, struct afs_file_status *status,
201 		       struct afs_callback *cb)
202 {
203 	struct afs_iget_data data = { .fid = *fid };
204 	struct afs_super_info *as;
205 	struct afs_vnode *vnode;
206 	struct inode *inode;
207 	int ret;
208 
209 	_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
210 
211 	as = sb->s_fs_info;
212 	data.volume = as->volume;
213 
214 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
215 			     &data);
216 	if (!inode) {
217 		_leave(" = -ENOMEM");
218 		return ERR_PTR(-ENOMEM);
219 	}
220 
221 	_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
222 	       inode, fid->vid, fid->vnode, fid->unique);
223 
224 	vnode = AFS_FS_I(inode);
225 
226 	/* deal with an existing inode */
227 	if (!(inode->i_state & I_NEW)) {
228 		_leave(" = %p", inode);
229 		return inode;
230 	}
231 
232 	if (!status) {
233 		/* it's a remotely extant inode */
234 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
235 		ret = afs_vnode_fetch_status(vnode, NULL, key);
236 		if (ret < 0)
237 			goto bad_inode;
238 	} else {
239 		/* it's an inode we just created */
240 		memcpy(&vnode->status, status, sizeof(vnode->status));
241 
242 		if (!cb) {
243 			/* it's a symlink we just created (the fileserver
244 			 * didn't give us a callback) */
245 			vnode->cb_version = 0;
246 			vnode->cb_expiry = 0;
247 			vnode->cb_type = 0;
248 			vnode->cb_expires = get_seconds();
249 		} else {
250 			vnode->cb_version = cb->version;
251 			vnode->cb_expiry = cb->expiry;
252 			vnode->cb_type = cb->type;
253 			vnode->cb_expires = vnode->cb_expiry + get_seconds();
254 		}
255 	}
256 
257 	/* set up caching before mapping the status, as map-status reads the
258 	 * first page of symlinks to see if they're really mountpoints */
259 	inode->i_size = vnode->status.size;
260 #ifdef CONFIG_AFS_FSCACHE
261 	vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
262 					      &afs_vnode_cache_index_def,
263 					      vnode, true);
264 #endif
265 
266 	ret = afs_inode_map_status(vnode, key);
267 	if (ret < 0)
268 		goto bad_inode;
269 
270 	/* success */
271 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
272 	inode->i_flags |= S_NOATIME;
273 	unlock_new_inode(inode);
274 	_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
275 	return inode;
276 
277 	/* failure */
278 bad_inode:
279 #ifdef CONFIG_AFS_FSCACHE
280 	fscache_relinquish_cookie(vnode->cache, 0);
281 	vnode->cache = NULL;
282 #endif
283 	iget_failed(inode);
284 	_leave(" = %d [bad]", ret);
285 	return ERR_PTR(ret);
286 }
287 
288 /*
289  * mark the data attached to an inode as obsolete due to a write on the server
290  * - might also want to ditch all the outstanding writes and dirty pages
291  */
292 void afs_zap_data(struct afs_vnode *vnode)
293 {
294 	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
295 
296 	/* nuke all the non-dirty pages that aren't locked, mapped or being
297 	 * written back in a regular file and completely discard the pages in a
298 	 * directory or symlink */
299 	if (S_ISREG(vnode->vfs_inode.i_mode))
300 		invalidate_remote_inode(&vnode->vfs_inode);
301 	else
302 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
303 }
304 
305 /*
306  * validate a vnode/inode
307  * - there are several things we need to check
308  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
309  *     symlink)
310  *   - parent dir metadata changed (security changes)
311  *   - dentry data changed (write, truncate)
312  *   - dentry metadata changed (security changes)
313  */
314 int afs_validate(struct afs_vnode *vnode, struct key *key)
315 {
316 	int ret;
317 
318 	_enter("{v={%x:%u} fl=%lx},%x",
319 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
320 	       key_serial(key));
321 
322 	if (vnode->cb_promised &&
323 	    !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
324 	    !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
325 	    !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
326 		if (vnode->cb_expires < get_seconds() + 10) {
327 			_debug("callback expired");
328 			set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
329 		} else {
330 			goto valid;
331 		}
332 	}
333 
334 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
335 		goto valid;
336 
337 	mutex_lock(&vnode->validate_lock);
338 
339 	/* if the promise has expired, we need to check the server again to get
340 	 * a new promise - note that if the (parent) directory's metadata was
341 	 * changed then the security may be different and we may no longer have
342 	 * access */
343 	if (!vnode->cb_promised ||
344 	    test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
345 		_debug("not promised");
346 		ret = afs_vnode_fetch_status(vnode, NULL, key);
347 		if (ret < 0)
348 			goto error_unlock;
349 		_debug("new promise [fl=%lx]", vnode->flags);
350 	}
351 
352 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
353 		_debug("file already deleted");
354 		ret = -ESTALE;
355 		goto error_unlock;
356 	}
357 
358 	/* if the vnode's data version number changed then its contents are
359 	 * different */
360 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
361 		afs_zap_data(vnode);
362 
363 	clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
364 	mutex_unlock(&vnode->validate_lock);
365 valid:
366 	_leave(" = 0");
367 	return 0;
368 
369 error_unlock:
370 	mutex_unlock(&vnode->validate_lock);
371 	_leave(" = %d", ret);
372 	return ret;
373 }
374 
375 /*
376  * read the attributes of an inode
377  */
378 int afs_getattr(const struct path *path, struct kstat *stat,
379 		u32 request_mask, unsigned int query_flags)
380 {
381 	struct inode *inode = d_inode(path->dentry);
382 
383 	_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
384 
385 	generic_fillattr(inode, stat);
386 	return 0;
387 }
388 
389 /*
390  * discard an AFS inode
391  */
392 int afs_drop_inode(struct inode *inode)
393 {
394 	_enter("");
395 
396 	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
397 		return generic_delete_inode(inode);
398 	else
399 		return generic_drop_inode(inode);
400 }
401 
402 /*
403  * clear an AFS inode
404  */
405 void afs_evict_inode(struct inode *inode)
406 {
407 	struct afs_permits *permits;
408 	struct afs_vnode *vnode;
409 
410 	vnode = AFS_FS_I(inode);
411 
412 	_enter("{%x:%u.%d} v=%u x=%u t=%u }",
413 	       vnode->fid.vid,
414 	       vnode->fid.vnode,
415 	       vnode->fid.unique,
416 	       vnode->cb_version,
417 	       vnode->cb_expiry,
418 	       vnode->cb_type);
419 
420 	_debug("CLEAR INODE %p", inode);
421 
422 	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
423 
424 	truncate_inode_pages_final(&inode->i_data);
425 	clear_inode(inode);
426 
427 	afs_give_up_callback(vnode);
428 
429 	if (vnode->server) {
430 		spin_lock(&vnode->server->fs_lock);
431 		rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
432 		spin_unlock(&vnode->server->fs_lock);
433 		afs_put_server(vnode->server);
434 		vnode->server = NULL;
435 	}
436 
437 	ASSERT(list_empty(&vnode->writebacks));
438 	ASSERT(!vnode->cb_promised);
439 
440 #ifdef CONFIG_AFS_FSCACHE
441 	fscache_relinquish_cookie(vnode->cache, 0);
442 	vnode->cache = NULL;
443 #endif
444 
445 	mutex_lock(&vnode->permits_lock);
446 	permits = vnode->permits;
447 	rcu_assign_pointer(vnode->permits, NULL);
448 	mutex_unlock(&vnode->permits_lock);
449 	if (permits)
450 		call_rcu(&permits->rcu, afs_zap_permits);
451 
452 	_leave("");
453 }
454 
455 /*
456  * set the attributes of an inode
457  */
458 int afs_setattr(struct dentry *dentry, struct iattr *attr)
459 {
460 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
461 	struct key *key;
462 	int ret;
463 
464 	_enter("{%x:%u},{n=%pd},%x",
465 	       vnode->fid.vid, vnode->fid.vnode, dentry,
466 	       attr->ia_valid);
467 
468 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
469 				ATTR_MTIME))) {
470 		_leave(" = 0 [unsupported]");
471 		return 0;
472 	}
473 
474 	/* flush any dirty data outstanding on a regular file */
475 	if (S_ISREG(vnode->vfs_inode.i_mode)) {
476 		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
477 		afs_writeback_all(vnode);
478 	}
479 
480 	if (attr->ia_valid & ATTR_FILE) {
481 		key = attr->ia_file->private_data;
482 	} else {
483 		key = afs_request_key(vnode->volume->cell);
484 		if (IS_ERR(key)) {
485 			ret = PTR_ERR(key);
486 			goto error;
487 		}
488 	}
489 
490 	ret = afs_vnode_setattr(vnode, key, attr);
491 	if (!(attr->ia_valid & ATTR_FILE))
492 		key_put(key);
493 
494 error:
495 	_leave(" = %d", ret);
496 	return ret;
497 }
498