xref: /openbmc/linux/fs/afs/inode.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f) 
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 		break;
60 	default:
61 		printk("kAFS: AFS vnode with undefined type\n");
62 		return -EBADMSG;
63 	}
64 
65 #ifdef CONFIG_AFS_FSCACHE
66 	if (vnode->status.size != inode->i_size)
67 		fscache_attr_changed(vnode->cache);
68 #endif
69 
70 	inode->i_nlink		= vnode->status.nlink;
71 	inode->i_uid		= vnode->status.owner;
72 	inode->i_gid		= 0;
73 	inode->i_size		= vnode->status.size;
74 	inode->i_ctime.tv_sec	= vnode->status.mtime_server;
75 	inode->i_ctime.tv_nsec	= 0;
76 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
77 	inode->i_blocks		= 0;
78 	inode->i_version	= vnode->fid.unique;
79 	inode->i_mapping->a_ops	= &afs_fs_aops;
80 
81 	/* check to see whether a symbolic link is really a mountpoint */
82 	if (vnode->status.type == AFS_FTYPE_SYMLINK) {
83 		afs_mntpt_check_symlink(vnode, key);
84 
85 		if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
86 			inode->i_mode	= S_IFDIR | vnode->status.mode;
87 			inode->i_op	= &afs_mntpt_inode_operations;
88 			inode->i_fop	= &afs_mntpt_file_operations;
89 		}
90 	}
91 
92 	return 0;
93 }
94 
95 /*
96  * iget5() comparator
97  */
98 static int afs_iget5_test(struct inode *inode, void *opaque)
99 {
100 	struct afs_iget_data *data = opaque;
101 
102 	return inode->i_ino == data->fid.vnode &&
103 		inode->i_version == data->fid.unique;
104 }
105 
106 /*
107  * iget5() comparator for inode created by autocell operations
108  *
109  * These pseudo inodes don't match anything.
110  */
111 static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
112 {
113 	return 0;
114 }
115 
116 /*
117  * iget5() inode initialiser
118  */
119 static int afs_iget5_set(struct inode *inode, void *opaque)
120 {
121 	struct afs_iget_data *data = opaque;
122 	struct afs_vnode *vnode = AFS_FS_I(inode);
123 
124 	inode->i_ino = data->fid.vnode;
125 	inode->i_version = data->fid.unique;
126 	vnode->fid = data->fid;
127 	vnode->volume = data->volume;
128 
129 	return 0;
130 }
131 
132 /*
133  * inode retrieval for autocell
134  */
135 struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
136 				int namesz, struct key *key)
137 {
138 	struct afs_iget_data data;
139 	struct afs_super_info *as;
140 	struct afs_vnode *vnode;
141 	struct super_block *sb;
142 	struct inode *inode;
143 	static atomic_t afs_autocell_ino;
144 
145 	_enter("{%x:%u},%*.*s,",
146 	       AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
147 	       namesz, namesz, dev_name ?: "");
148 
149 	sb = dir->i_sb;
150 	as = sb->s_fs_info;
151 	data.volume = as->volume;
152 	data.fid.vid = as->volume->vid;
153 	data.fid.unique = 0;
154 	data.fid.vnode = 0;
155 
156 	inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
157 			     afs_iget5_autocell_test, afs_iget5_set,
158 			     &data);
159 	if (!inode) {
160 		_leave(" = -ENOMEM");
161 		return ERR_PTR(-ENOMEM);
162 	}
163 
164 	_debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
165 	       inode, inode->i_ino, data.fid.vid, data.fid.vnode,
166 	       data.fid.unique);
167 
168 	vnode = AFS_FS_I(inode);
169 
170 	/* there shouldn't be an existing inode */
171 	BUG_ON(!(inode->i_state & I_NEW));
172 
173 	inode->i_size		= 0;
174 	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
175 	inode->i_op		= &afs_autocell_inode_operations;
176 	inode->i_nlink		= 2;
177 	inode->i_uid		= 0;
178 	inode->i_gid		= 0;
179 	inode->i_ctime.tv_sec	= get_seconds();
180 	inode->i_ctime.tv_nsec	= 0;
181 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
182 	inode->i_blocks		= 0;
183 	inode->i_version	= 0;
184 	inode->i_generation	= 0;
185 
186 	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
187 	inode->i_flags |= S_NOATIME;
188 	unlock_new_inode(inode);
189 	_leave(" = %p", inode);
190 	return inode;
191 }
192 
193 /*
194  * inode retrieval
195  */
196 struct inode *afs_iget(struct super_block *sb, struct key *key,
197 		       struct afs_fid *fid, struct afs_file_status *status,
198 		       struct afs_callback *cb)
199 {
200 	struct afs_iget_data data = { .fid = *fid };
201 	struct afs_super_info *as;
202 	struct afs_vnode *vnode;
203 	struct inode *inode;
204 	int ret;
205 
206 	_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
207 
208 	as = sb->s_fs_info;
209 	data.volume = as->volume;
210 
211 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
212 			     &data);
213 	if (!inode) {
214 		_leave(" = -ENOMEM");
215 		return ERR_PTR(-ENOMEM);
216 	}
217 
218 	_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
219 	       inode, fid->vid, fid->vnode, fid->unique);
220 
221 	vnode = AFS_FS_I(inode);
222 
223 	/* deal with an existing inode */
224 	if (!(inode->i_state & I_NEW)) {
225 		_leave(" = %p", inode);
226 		return inode;
227 	}
228 
229 	if (!status) {
230 		/* it's a remotely extant inode */
231 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
232 		ret = afs_vnode_fetch_status(vnode, NULL, key);
233 		if (ret < 0)
234 			goto bad_inode;
235 	} else {
236 		/* it's an inode we just created */
237 		memcpy(&vnode->status, status, sizeof(vnode->status));
238 
239 		if (!cb) {
240 			/* it's a symlink we just created (the fileserver
241 			 * didn't give us a callback) */
242 			vnode->cb_version = 0;
243 			vnode->cb_expiry = 0;
244 			vnode->cb_type = 0;
245 			vnode->cb_expires = get_seconds();
246 		} else {
247 			vnode->cb_version = cb->version;
248 			vnode->cb_expiry = cb->expiry;
249 			vnode->cb_type = cb->type;
250 			vnode->cb_expires = vnode->cb_expiry + get_seconds();
251 		}
252 	}
253 
254 	/* set up caching before mapping the status, as map-status reads the
255 	 * first page of symlinks to see if they're really mountpoints */
256 	inode->i_size = vnode->status.size;
257 #ifdef CONFIG_AFS_FSCACHE
258 	vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
259 					      &afs_vnode_cache_index_def,
260 					      vnode);
261 #endif
262 
263 	ret = afs_inode_map_status(vnode, key);
264 	if (ret < 0)
265 		goto bad_inode;
266 
267 	/* success */
268 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
269 	inode->i_flags |= S_NOATIME;
270 	unlock_new_inode(inode);
271 	_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
272 	return inode;
273 
274 	/* failure */
275 bad_inode:
276 #ifdef CONFIG_AFS_FSCACHE
277 	fscache_relinquish_cookie(vnode->cache, 0);
278 	vnode->cache = NULL;
279 #endif
280 	iget_failed(inode);
281 	_leave(" = %d [bad]", ret);
282 	return ERR_PTR(ret);
283 }
284 
285 /*
286  * mark the data attached to an inode as obsolete due to a write on the server
287  * - might also want to ditch all the outstanding writes and dirty pages
288  */
289 void afs_zap_data(struct afs_vnode *vnode)
290 {
291 	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
292 
293 	/* nuke all the non-dirty pages that aren't locked, mapped or being
294 	 * written back in a regular file and completely discard the pages in a
295 	 * directory or symlink */
296 	if (S_ISREG(vnode->vfs_inode.i_mode))
297 		invalidate_remote_inode(&vnode->vfs_inode);
298 	else
299 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
300 }
301 
302 /*
303  * validate a vnode/inode
304  * - there are several things we need to check
305  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
306  *     symlink)
307  *   - parent dir metadata changed (security changes)
308  *   - dentry data changed (write, truncate)
309  *   - dentry metadata changed (security changes)
310  */
311 int afs_validate(struct afs_vnode *vnode, struct key *key)
312 {
313 	int ret;
314 
315 	_enter("{v={%x:%u} fl=%lx},%x",
316 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
317 	       key_serial(key));
318 
319 	if (vnode->cb_promised &&
320 	    !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
321 	    !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
322 	    !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
323 		if (vnode->cb_expires < get_seconds() + 10) {
324 			_debug("callback expired");
325 			set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
326 		} else {
327 			goto valid;
328 		}
329 	}
330 
331 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
332 		goto valid;
333 
334 	mutex_lock(&vnode->validate_lock);
335 
336 	/* if the promise has expired, we need to check the server again to get
337 	 * a new promise - note that if the (parent) directory's metadata was
338 	 * changed then the security may be different and we may no longer have
339 	 * access */
340 	if (!vnode->cb_promised ||
341 	    test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
342 		_debug("not promised");
343 		ret = afs_vnode_fetch_status(vnode, NULL, key);
344 		if (ret < 0)
345 			goto error_unlock;
346 		_debug("new promise [fl=%lx]", vnode->flags);
347 	}
348 
349 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
350 		_debug("file already deleted");
351 		ret = -ESTALE;
352 		goto error_unlock;
353 	}
354 
355 	/* if the vnode's data version number changed then its contents are
356 	 * different */
357 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
358 		afs_zap_data(vnode);
359 
360 	clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
361 	mutex_unlock(&vnode->validate_lock);
362 valid:
363 	_leave(" = 0");
364 	return 0;
365 
366 error_unlock:
367 	mutex_unlock(&vnode->validate_lock);
368 	_leave(" = %d", ret);
369 	return ret;
370 }
371 
372 /*
373  * read the attributes of an inode
374  */
375 int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
376 		      struct kstat *stat)
377 {
378 	struct inode *inode;
379 
380 	inode = dentry->d_inode;
381 
382 	_enter("{ ino=%lu v=%llu }", inode->i_ino,
383 		(unsigned long long)inode->i_version);
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(&inode->i_data, 0);
425 	end_writeback(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(dentry->d_inode);
461 	struct key *key;
462 	int ret;
463 
464 	_enter("{%x:%u},{n=%s},%x",
465 	       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
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