xref: /openbmc/linux/fs/afs/inode.c (revision 565d76cb) 
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 	set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
188 	inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
189 	unlock_new_inode(inode);
190 	_leave(" = %p", inode);
191 	return inode;
192 }
193 
194 /*
195  * inode retrieval
196  */
197 struct inode *afs_iget(struct super_block *sb, struct key *key,
198 		       struct afs_fid *fid, struct afs_file_status *status,
199 		       struct afs_callback *cb)
200 {
201 	struct afs_iget_data data = { .fid = *fid };
202 	struct afs_super_info *as;
203 	struct afs_vnode *vnode;
204 	struct inode *inode;
205 	int ret;
206 
207 	_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
208 
209 	as = sb->s_fs_info;
210 	data.volume = as->volume;
211 
212 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
213 			     &data);
214 	if (!inode) {
215 		_leave(" = -ENOMEM");
216 		return ERR_PTR(-ENOMEM);
217 	}
218 
219 	_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
220 	       inode, fid->vid, fid->vnode, fid->unique);
221 
222 	vnode = AFS_FS_I(inode);
223 
224 	/* deal with an existing inode */
225 	if (!(inode->i_state & I_NEW)) {
226 		_leave(" = %p", inode);
227 		return inode;
228 	}
229 
230 	if (!status) {
231 		/* it's a remotely extant inode */
232 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
233 		ret = afs_vnode_fetch_status(vnode, NULL, key);
234 		if (ret < 0)
235 			goto bad_inode;
236 	} else {
237 		/* it's an inode we just created */
238 		memcpy(&vnode->status, status, sizeof(vnode->status));
239 
240 		if (!cb) {
241 			/* it's a symlink we just created (the fileserver
242 			 * didn't give us a callback) */
243 			vnode->cb_version = 0;
244 			vnode->cb_expiry = 0;
245 			vnode->cb_type = 0;
246 			vnode->cb_expires = get_seconds();
247 		} else {
248 			vnode->cb_version = cb->version;
249 			vnode->cb_expiry = cb->expiry;
250 			vnode->cb_type = cb->type;
251 			vnode->cb_expires = vnode->cb_expiry + get_seconds();
252 		}
253 	}
254 
255 	/* set up caching before mapping the status, as map-status reads the
256 	 * first page of symlinks to see if they're really mountpoints */
257 	inode->i_size = vnode->status.size;
258 #ifdef CONFIG_AFS_FSCACHE
259 	vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
260 					      &afs_vnode_cache_index_def,
261 					      vnode);
262 #endif
263 
264 	ret = afs_inode_map_status(vnode, key);
265 	if (ret < 0)
266 		goto bad_inode;
267 
268 	/* success */
269 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
270 	inode->i_flags |= S_NOATIME;
271 	unlock_new_inode(inode);
272 	_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
273 	return inode;
274 
275 	/* failure */
276 bad_inode:
277 #ifdef CONFIG_AFS_FSCACHE
278 	fscache_relinquish_cookie(vnode->cache, 0);
279 	vnode->cache = NULL;
280 #endif
281 	iget_failed(inode);
282 	_leave(" = %d [bad]", ret);
283 	return ERR_PTR(ret);
284 }
285 
286 /*
287  * mark the data attached to an inode as obsolete due to a write on the server
288  * - might also want to ditch all the outstanding writes and dirty pages
289  */
290 void afs_zap_data(struct afs_vnode *vnode)
291 {
292 	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
293 
294 	/* nuke all the non-dirty pages that aren't locked, mapped or being
295 	 * written back in a regular file and completely discard the pages in a
296 	 * directory or symlink */
297 	if (S_ISREG(vnode->vfs_inode.i_mode))
298 		invalidate_remote_inode(&vnode->vfs_inode);
299 	else
300 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
301 }
302 
303 /*
304  * validate a vnode/inode
305  * - there are several things we need to check
306  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
307  *     symlink)
308  *   - parent dir metadata changed (security changes)
309  *   - dentry data changed (write, truncate)
310  *   - dentry metadata changed (security changes)
311  */
312 int afs_validate(struct afs_vnode *vnode, struct key *key)
313 {
314 	int ret;
315 
316 	_enter("{v={%x:%u} fl=%lx},%x",
317 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
318 	       key_serial(key));
319 
320 	if (vnode->cb_promised &&
321 	    !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
322 	    !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
323 	    !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
324 		if (vnode->cb_expires < get_seconds() + 10) {
325 			_debug("callback expired");
326 			set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
327 		} else {
328 			goto valid;
329 		}
330 	}
331 
332 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
333 		goto valid;
334 
335 	mutex_lock(&vnode->validate_lock);
336 
337 	/* if the promise has expired, we need to check the server again to get
338 	 * a new promise - note that if the (parent) directory's metadata was
339 	 * changed then the security may be different and we may no longer have
340 	 * access */
341 	if (!vnode->cb_promised ||
342 	    test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
343 		_debug("not promised");
344 		ret = afs_vnode_fetch_status(vnode, NULL, key);
345 		if (ret < 0)
346 			goto error_unlock;
347 		_debug("new promise [fl=%lx]", vnode->flags);
348 	}
349 
350 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
351 		_debug("file already deleted");
352 		ret = -ESTALE;
353 		goto error_unlock;
354 	}
355 
356 	/* if the vnode's data version number changed then its contents are
357 	 * different */
358 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
359 		afs_zap_data(vnode);
360 
361 	clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
362 	mutex_unlock(&vnode->validate_lock);
363 valid:
364 	_leave(" = 0");
365 	return 0;
366 
367 error_unlock:
368 	mutex_unlock(&vnode->validate_lock);
369 	_leave(" = %d", ret);
370 	return ret;
371 }
372 
373 /*
374  * read the attributes of an inode
375  */
376 int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
377 		      struct kstat *stat)
378 {
379 	struct inode *inode;
380 
381 	inode = dentry->d_inode;
382 
383 	_enter("{ ino=%lu v=%llu }", inode->i_ino,
384 		(unsigned long long)inode->i_version);
385 
386 	generic_fillattr(inode, stat);
387 	return 0;
388 }
389 
390 /*
391  * discard an AFS inode
392  */
393 int afs_drop_inode(struct inode *inode)
394 {
395 	_enter("");
396 
397 	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
398 		return generic_delete_inode(inode);
399 	else
400 		return generic_drop_inode(inode);
401 }
402 
403 /*
404  * clear an AFS inode
405  */
406 void afs_evict_inode(struct inode *inode)
407 {
408 	struct afs_permits *permits;
409 	struct afs_vnode *vnode;
410 
411 	vnode = AFS_FS_I(inode);
412 
413 	_enter("{%x:%u.%d} v=%u x=%u t=%u }",
414 	       vnode->fid.vid,
415 	       vnode->fid.vnode,
416 	       vnode->fid.unique,
417 	       vnode->cb_version,
418 	       vnode->cb_expiry,
419 	       vnode->cb_type);
420 
421 	_debug("CLEAR INODE %p", inode);
422 
423 	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
424 
425 	truncate_inode_pages(&inode->i_data, 0);
426 	end_writeback(inode);
427 
428 	afs_give_up_callback(vnode);
429 
430 	if (vnode->server) {
431 		spin_lock(&vnode->server->fs_lock);
432 		rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
433 		spin_unlock(&vnode->server->fs_lock);
434 		afs_put_server(vnode->server);
435 		vnode->server = NULL;
436 	}
437 
438 	ASSERT(list_empty(&vnode->writebacks));
439 	ASSERT(!vnode->cb_promised);
440 
441 #ifdef CONFIG_AFS_FSCACHE
442 	fscache_relinquish_cookie(vnode->cache, 0);
443 	vnode->cache = NULL;
444 #endif
445 
446 	mutex_lock(&vnode->permits_lock);
447 	permits = vnode->permits;
448 	rcu_assign_pointer(vnode->permits, NULL);
449 	mutex_unlock(&vnode->permits_lock);
450 	if (permits)
451 		call_rcu(&permits->rcu, afs_zap_permits);
452 
453 	_leave("");
454 }
455 
456 /*
457  * set the attributes of an inode
458  */
459 int afs_setattr(struct dentry *dentry, struct iattr *attr)
460 {
461 	struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
462 	struct key *key;
463 	int ret;
464 
465 	_enter("{%x:%u},{n=%s},%x",
466 	       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
467 	       attr->ia_valid);
468 
469 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
470 				ATTR_MTIME))) {
471 		_leave(" = 0 [unsupported]");
472 		return 0;
473 	}
474 
475 	/* flush any dirty data outstanding on a regular file */
476 	if (S_ISREG(vnode->vfs_inode.i_mode)) {
477 		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
478 		afs_writeback_all(vnode);
479 	}
480 
481 	if (attr->ia_valid & ATTR_FILE) {
482 		key = attr->ia_file->private_data;
483 	} else {
484 		key = afs_request_key(vnode->volume->cell);
485 		if (IS_ERR(key)) {
486 			ret = PTR_ERR(key);
487 			goto error;
488 		}
489 	}
490 
491 	ret = afs_vnode_setattr(vnode, key, attr);
492 	if (!(attr->ia_valid & ATTR_FILE))
493 		key_put(key);
494 
495 error:
496 	_leave(" = %d", ret);
497 	return ret;
498 }
499