xref: /openbmc/linux/fs/afs/inode.c (revision e5c86679) 
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 		/* Symlinks with a mode of 0644 are actually mountpoints. */
58 		if ((vnode->status.mode & 0777) == 0644) {
59 			inode->i_flags |= S_AUTOMOUNT;
60 
61 			spin_lock(&vnode->lock);
62 			set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
63 			spin_unlock(&vnode->lock);
64 
65 			inode->i_mode	= S_IFDIR | 0555;
66 			inode->i_op	= &afs_mntpt_inode_operations;
67 			inode->i_fop	= &afs_mntpt_file_operations;
68 		} else {
69 			inode->i_mode	= S_IFLNK | vnode->status.mode;
70 			inode->i_op	= &page_symlink_inode_operations;
71 		}
72 		inode_nohighmem(inode);
73 		break;
74 	default:
75 		printk("kAFS: AFS vnode with undefined type\n");
76 		return -EBADMSG;
77 	}
78 
79 #ifdef CONFIG_AFS_FSCACHE
80 	if (vnode->status.size != inode->i_size)
81 		fscache_attr_changed(vnode->cache);
82 #endif
83 
84 	set_nlink(inode, vnode->status.nlink);
85 	inode->i_uid		= vnode->status.owner;
86 	inode->i_gid            = vnode->status.group;
87 	inode->i_size		= vnode->status.size;
88 	inode->i_ctime.tv_sec	= vnode->status.mtime_client;
89 	inode->i_ctime.tv_nsec	= 0;
90 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
91 	inode->i_blocks		= 0;
92 	inode->i_generation	= vnode->fid.unique;
93 	inode->i_version	= vnode->status.data_version;
94 	inode->i_mapping->a_ops	= &afs_fs_aops;
95 	return 0;
96 }
97 
98 /*
99  * iget5() comparator
100  */
101 static int afs_iget5_test(struct inode *inode, void *opaque)
102 {
103 	struct afs_iget_data *data = opaque;
104 
105 	return inode->i_ino == data->fid.vnode &&
106 		inode->i_generation == data->fid.unique;
107 }
108 
109 /*
110  * iget5() comparator for inode created by autocell operations
111  *
112  * These pseudo inodes don't match anything.
113  */
114 static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
115 {
116 	return 0;
117 }
118 
119 /*
120  * iget5() inode initialiser
121  */
122 static int afs_iget5_set(struct inode *inode, void *opaque)
123 {
124 	struct afs_iget_data *data = opaque;
125 	struct afs_vnode *vnode = AFS_FS_I(inode);
126 
127 	inode->i_ino = data->fid.vnode;
128 	inode->i_generation = data->fid.unique;
129 	vnode->fid = data->fid;
130 	vnode->volume = data->volume;
131 
132 	return 0;
133 }
134 
135 /*
136  * inode retrieval for autocell
137  */
138 struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
139 				int namesz, struct key *key)
140 {
141 	struct afs_iget_data data;
142 	struct afs_super_info *as;
143 	struct afs_vnode *vnode;
144 	struct super_block *sb;
145 	struct inode *inode;
146 	static atomic_t afs_autocell_ino;
147 
148 	_enter("{%x:%u},%*.*s,",
149 	       AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
150 	       namesz, namesz, dev_name ?: "");
151 
152 	sb = dir->i_sb;
153 	as = sb->s_fs_info;
154 	data.volume = as->volume;
155 	data.fid.vid = as->volume->vid;
156 	data.fid.unique = 0;
157 	data.fid.vnode = 0;
158 
159 	inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
160 			     afs_iget5_autocell_test, afs_iget5_set,
161 			     &data);
162 	if (!inode) {
163 		_leave(" = -ENOMEM");
164 		return ERR_PTR(-ENOMEM);
165 	}
166 
167 	_debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
168 	       inode, inode->i_ino, data.fid.vid, data.fid.vnode,
169 	       data.fid.unique);
170 
171 	vnode = AFS_FS_I(inode);
172 
173 	/* there shouldn't be an existing inode */
174 	BUG_ON(!(inode->i_state & I_NEW));
175 
176 	inode->i_size		= 0;
177 	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
178 	inode->i_op		= &afs_autocell_inode_operations;
179 	set_nlink(inode, 2);
180 	inode->i_uid		= GLOBAL_ROOT_UID;
181 	inode->i_gid		= GLOBAL_ROOT_GID;
182 	inode->i_ctime.tv_sec	= get_seconds();
183 	inode->i_ctime.tv_nsec	= 0;
184 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
185 	inode->i_blocks		= 0;
186 	inode->i_version	= 0;
187 	inode->i_generation	= 0;
188 
189 	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
190 	set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
191 	inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
192 	unlock_new_inode(inode);
193 	_leave(" = %p", inode);
194 	return inode;
195 }
196 
197 /*
198  * inode retrieval
199  */
200 struct inode *afs_iget(struct super_block *sb, struct key *key,
201 		       struct afs_fid *fid, struct afs_file_status *status,
202 		       struct afs_callback *cb)
203 {
204 	struct afs_iget_data data = { .fid = *fid };
205 	struct afs_super_info *as;
206 	struct afs_vnode *vnode;
207 	struct inode *inode;
208 	int ret;
209 
210 	_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
211 
212 	as = sb->s_fs_info;
213 	data.volume = as->volume;
214 
215 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
216 			     &data);
217 	if (!inode) {
218 		_leave(" = -ENOMEM");
219 		return ERR_PTR(-ENOMEM);
220 	}
221 
222 	_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
223 	       inode, fid->vid, fid->vnode, fid->unique);
224 
225 	vnode = AFS_FS_I(inode);
226 
227 	/* deal with an existing inode */
228 	if (!(inode->i_state & I_NEW)) {
229 		_leave(" = %p", inode);
230 		return inode;
231 	}
232 
233 	if (!status) {
234 		/* it's a remotely extant inode */
235 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
236 		ret = afs_vnode_fetch_status(vnode, NULL, key);
237 		if (ret < 0)
238 			goto bad_inode;
239 	} else {
240 		/* it's an inode we just created */
241 		memcpy(&vnode->status, status, sizeof(vnode->status));
242 
243 		if (!cb) {
244 			/* it's a symlink we just created (the fileserver
245 			 * didn't give us a callback) */
246 			vnode->cb_version = 0;
247 			vnode->cb_expiry = 0;
248 			vnode->cb_type = 0;
249 			vnode->cb_expires = ktime_get_real_seconds();
250 		} else {
251 			vnode->cb_version = cb->version;
252 			vnode->cb_expiry = cb->expiry;
253 			vnode->cb_type = cb->type;
254 			vnode->cb_expires = vnode->cb_expiry +
255 				ktime_get_real_seconds();
256 		}
257 	}
258 
259 	/* set up caching before mapping the status, as map-status reads the
260 	 * first page of symlinks to see if they're really mountpoints */
261 	inode->i_size = vnode->status.size;
262 #ifdef CONFIG_AFS_FSCACHE
263 	vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
264 					      &afs_vnode_cache_index_def,
265 					      vnode, true);
266 #endif
267 
268 	ret = afs_inode_map_status(vnode, key);
269 	if (ret < 0)
270 		goto bad_inode;
271 
272 	/* success */
273 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
274 	inode->i_flags |= S_NOATIME;
275 	unlock_new_inode(inode);
276 	_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
277 	return inode;
278 
279 	/* failure */
280 bad_inode:
281 #ifdef CONFIG_AFS_FSCACHE
282 	fscache_relinquish_cookie(vnode->cache, 0);
283 	vnode->cache = NULL;
284 #endif
285 	iget_failed(inode);
286 	_leave(" = %d [bad]", ret);
287 	return ERR_PTR(ret);
288 }
289 
290 /*
291  * mark the data attached to an inode as obsolete due to a write on the server
292  * - might also want to ditch all the outstanding writes and dirty pages
293  */
294 void afs_zap_data(struct afs_vnode *vnode)
295 {
296 	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
297 
298 	/* nuke all the non-dirty pages that aren't locked, mapped or being
299 	 * written back in a regular file and completely discard the pages in a
300 	 * directory or symlink */
301 	if (S_ISREG(vnode->vfs_inode.i_mode))
302 		invalidate_remote_inode(&vnode->vfs_inode);
303 	else
304 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
305 }
306 
307 /*
308  * validate a vnode/inode
309  * - there are several things we need to check
310  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
311  *     symlink)
312  *   - parent dir metadata changed (security changes)
313  *   - dentry data changed (write, truncate)
314  *   - dentry metadata changed (security changes)
315  */
316 int afs_validate(struct afs_vnode *vnode, struct key *key)
317 {
318 	int ret;
319 
320 	_enter("{v={%x:%u} fl=%lx},%x",
321 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
322 	       key_serial(key));
323 
324 	if (vnode->cb_promised &&
325 	    !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
326 	    !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
327 	    !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
328 		if (vnode->cb_expires < ktime_get_real_seconds() + 10) {
329 			_debug("callback expired");
330 			set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
331 		} else {
332 			goto valid;
333 		}
334 	}
335 
336 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
337 		goto valid;
338 
339 	mutex_lock(&vnode->validate_lock);
340 
341 	/* if the promise has expired, we need to check the server again to get
342 	 * a new promise - note that if the (parent) directory's metadata was
343 	 * changed then the security may be different and we may no longer have
344 	 * access */
345 	if (!vnode->cb_promised ||
346 	    test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
347 		_debug("not promised");
348 		ret = afs_vnode_fetch_status(vnode, NULL, key);
349 		if (ret < 0)
350 			goto error_unlock;
351 		_debug("new promise [fl=%lx]", vnode->flags);
352 	}
353 
354 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
355 		_debug("file already deleted");
356 		ret = -ESTALE;
357 		goto error_unlock;
358 	}
359 
360 	/* if the vnode's data version number changed then its contents are
361 	 * different */
362 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
363 		afs_zap_data(vnode);
364 
365 	clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
366 	mutex_unlock(&vnode->validate_lock);
367 valid:
368 	_leave(" = 0");
369 	return 0;
370 
371 error_unlock:
372 	mutex_unlock(&vnode->validate_lock);
373 	_leave(" = %d", ret);
374 	return ret;
375 }
376 
377 /*
378  * read the attributes of an inode
379  */
380 int afs_getattr(const struct path *path, struct kstat *stat,
381 		u32 request_mask, unsigned int query_flags)
382 {
383 	struct inode *inode = d_inode(path->dentry);
384 
385 	_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
386 
387 	generic_fillattr(inode, stat);
388 	return 0;
389 }
390 
391 /*
392  * discard an AFS inode
393  */
394 int afs_drop_inode(struct inode *inode)
395 {
396 	_enter("");
397 
398 	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
399 		return generic_delete_inode(inode);
400 	else
401 		return generic_drop_inode(inode);
402 }
403 
404 /*
405  * clear an AFS inode
406  */
407 void afs_evict_inode(struct inode *inode)
408 {
409 	struct afs_permits *permits;
410 	struct afs_vnode *vnode;
411 
412 	vnode = AFS_FS_I(inode);
413 
414 	_enter("{%x:%u.%d} v=%u x=%u t=%u }",
415 	       vnode->fid.vid,
416 	       vnode->fid.vnode,
417 	       vnode->fid.unique,
418 	       vnode->cb_version,
419 	       vnode->cb_expiry,
420 	       vnode->cb_type);
421 
422 	_debug("CLEAR INODE %p", inode);
423 
424 	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
425 
426 	truncate_inode_pages_final(&inode->i_data);
427 	clear_inode(inode);
428 
429 	afs_give_up_callback(vnode);
430 
431 	if (vnode->server) {
432 		spin_lock(&vnode->server->fs_lock);
433 		rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
434 		spin_unlock(&vnode->server->fs_lock);
435 		afs_put_server(vnode->server);
436 		vnode->server = NULL;
437 	}
438 
439 	ASSERT(list_empty(&vnode->writebacks));
440 	ASSERT(!vnode->cb_promised);
441 
442 #ifdef CONFIG_AFS_FSCACHE
443 	fscache_relinquish_cookie(vnode->cache, 0);
444 	vnode->cache = NULL;
445 #endif
446 
447 	mutex_lock(&vnode->permits_lock);
448 	permits = vnode->permits;
449 	RCU_INIT_POINTER(vnode->permits, NULL);
450 	mutex_unlock(&vnode->permits_lock);
451 	if (permits)
452 		call_rcu(&permits->rcu, afs_zap_permits);
453 
454 	_leave("");
455 }
456 
457 /*
458  * set the attributes of an inode
459  */
460 int afs_setattr(struct dentry *dentry, struct iattr *attr)
461 {
462 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
463 	struct key *key;
464 	int ret;
465 
466 	_enter("{%x:%u},{n=%pd},%x",
467 	       vnode->fid.vid, vnode->fid.vnode, dentry,
468 	       attr->ia_valid);
469 
470 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
471 				ATTR_MTIME))) {
472 		_leave(" = 0 [unsupported]");
473 		return 0;
474 	}
475 
476 	/* flush any dirty data outstanding on a regular file */
477 	if (S_ISREG(vnode->vfs_inode.i_mode)) {
478 		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
479 		afs_writeback_all(vnode);
480 	}
481 
482 	if (attr->ia_valid & ATTR_FILE) {
483 		key = attr->ia_file->private_data;
484 	} else {
485 		key = afs_request_key(vnode->volume->cell);
486 		if (IS_ERR(key)) {
487 			ret = PTR_ERR(key);
488 			goto error;
489 		}
490 	}
491 
492 	ret = afs_vnode_setattr(vnode, key, attr);
493 	if (!(attr->ia_valid & ATTR_FILE))
494 		key_put(key);
495 
496 error:
497 	_leave(" = %d", ret);
498 	return ret;
499 }
500