xref: /openbmc/linux/fs/afs/inode.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
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/slab.h>
20 #include <linux/fs.h>
21 #include <linux/pagemap.h>
22 #include <linux/sched.h>
23 #include "internal.h"
24 
25 struct afs_iget_data {
26 	struct afs_fid		fid;
27 	struct afs_volume	*volume;	/* volume on which resides */
28 };
29 
30 /*
31  * map the AFS file status to the inode member variables
32  */
33 static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
34 {
35 	struct inode *inode = AFS_VNODE_TO_I(vnode);
36 
37 	_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
38 	       vnode->status.type,
39 	       vnode->status.nlink,
40 	       (unsigned long long) vnode->status.size,
41 	       vnode->status.data_version,
42 	       vnode->status.mode);
43 
44 	switch (vnode->status.type) {
45 	case AFS_FTYPE_FILE:
46 		inode->i_mode	= S_IFREG | vnode->status.mode;
47 		inode->i_op	= &afs_file_inode_operations;
48 		inode->i_fop	= &afs_file_operations;
49 		break;
50 	case AFS_FTYPE_DIR:
51 		inode->i_mode	= S_IFDIR | vnode->status.mode;
52 		inode->i_op	= &afs_dir_inode_operations;
53 		inode->i_fop	= &afs_dir_file_operations;
54 		break;
55 	case AFS_FTYPE_SYMLINK:
56 		inode->i_mode	= S_IFLNK | vnode->status.mode;
57 		inode->i_op	= &page_symlink_inode_operations;
58 		break;
59 	default:
60 		printk("kAFS: AFS vnode with undefined type\n");
61 		return -EBADMSG;
62 	}
63 
64 #ifdef CONFIG_AFS_FSCACHE
65 	if (vnode->status.size != inode->i_size)
66 		fscache_attr_changed(vnode->cache);
67 #endif
68 
69 	inode->i_nlink		= vnode->status.nlink;
70 	inode->i_uid		= vnode->status.owner;
71 	inode->i_gid		= 0;
72 	inode->i_size		= vnode->status.size;
73 	inode->i_ctime.tv_sec	= vnode->status.mtime_server;
74 	inode->i_ctime.tv_nsec	= 0;
75 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
76 	inode->i_blocks		= 0;
77 	inode->i_version	= vnode->fid.unique;
78 	inode->i_mapping->a_ops	= &afs_fs_aops;
79 
80 	/* check to see whether a symbolic link is really a mountpoint */
81 	if (vnode->status.type == AFS_FTYPE_SYMLINK) {
82 		afs_mntpt_check_symlink(vnode, key);
83 
84 		if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
85 			inode->i_mode	= S_IFDIR | vnode->status.mode;
86 			inode->i_op	= &afs_mntpt_inode_operations;
87 			inode->i_fop	= &afs_mntpt_file_operations;
88 		}
89 	}
90 
91 	return 0;
92 }
93 
94 /*
95  * iget5() comparator
96  */
97 static int afs_iget5_test(struct inode *inode, void *opaque)
98 {
99 	struct afs_iget_data *data = opaque;
100 
101 	return inode->i_ino == data->fid.vnode &&
102 		inode->i_version == data->fid.unique;
103 }
104 
105 /*
106  * iget5() inode initialiser
107  */
108 static int afs_iget5_set(struct inode *inode, void *opaque)
109 {
110 	struct afs_iget_data *data = opaque;
111 	struct afs_vnode *vnode = AFS_FS_I(inode);
112 
113 	inode->i_ino = data->fid.vnode;
114 	inode->i_version = data->fid.unique;
115 	vnode->fid = data->fid;
116 	vnode->volume = data->volume;
117 
118 	return 0;
119 }
120 
121 /*
122  * inode retrieval
123  */
124 struct inode *afs_iget(struct super_block *sb, struct key *key,
125 		       struct afs_fid *fid, struct afs_file_status *status,
126 		       struct afs_callback *cb)
127 {
128 	struct afs_iget_data data = { .fid = *fid };
129 	struct afs_super_info *as;
130 	struct afs_vnode *vnode;
131 	struct inode *inode;
132 	int ret;
133 
134 	_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
135 
136 	as = sb->s_fs_info;
137 	data.volume = as->volume;
138 
139 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
140 			     &data);
141 	if (!inode) {
142 		_leave(" = -ENOMEM");
143 		return ERR_PTR(-ENOMEM);
144 	}
145 
146 	_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
147 	       inode, fid->vid, fid->vnode, fid->unique);
148 
149 	vnode = AFS_FS_I(inode);
150 
151 	/* deal with an existing inode */
152 	if (!(inode->i_state & I_NEW)) {
153 		_leave(" = %p", inode);
154 		return inode;
155 	}
156 
157 	if (!status) {
158 		/* it's a remotely extant inode */
159 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
160 		ret = afs_vnode_fetch_status(vnode, NULL, key);
161 		if (ret < 0)
162 			goto bad_inode;
163 	} else {
164 		/* it's an inode we just created */
165 		memcpy(&vnode->status, status, sizeof(vnode->status));
166 
167 		if (!cb) {
168 			/* it's a symlink we just created (the fileserver
169 			 * didn't give us a callback) */
170 			vnode->cb_version = 0;
171 			vnode->cb_expiry = 0;
172 			vnode->cb_type = 0;
173 			vnode->cb_expires = get_seconds();
174 		} else {
175 			vnode->cb_version = cb->version;
176 			vnode->cb_expiry = cb->expiry;
177 			vnode->cb_type = cb->type;
178 			vnode->cb_expires = vnode->cb_expiry + get_seconds();
179 		}
180 	}
181 
182 	/* set up caching before mapping the status, as map-status reads the
183 	 * first page of symlinks to see if they're really mountpoints */
184 	inode->i_size = vnode->status.size;
185 #ifdef CONFIG_AFS_FSCACHE
186 	vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
187 					      &afs_vnode_cache_index_def,
188 					      vnode);
189 #endif
190 
191 	ret = afs_inode_map_status(vnode, key);
192 	if (ret < 0)
193 		goto bad_inode;
194 
195 	/* success */
196 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
197 	inode->i_flags |= S_NOATIME;
198 	unlock_new_inode(inode);
199 	_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
200 	return inode;
201 
202 	/* failure */
203 bad_inode:
204 #ifdef CONFIG_AFS_FSCACHE
205 	fscache_relinquish_cookie(vnode->cache, 0);
206 	vnode->cache = NULL;
207 #endif
208 	iget_failed(inode);
209 	_leave(" = %d [bad]", ret);
210 	return ERR_PTR(ret);
211 }
212 
213 /*
214  * mark the data attached to an inode as obsolete due to a write on the server
215  * - might also want to ditch all the outstanding writes and dirty pages
216  */
217 void afs_zap_data(struct afs_vnode *vnode)
218 {
219 	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
220 
221 	/* nuke all the non-dirty pages that aren't locked, mapped or being
222 	 * written back in a regular file and completely discard the pages in a
223 	 * directory or symlink */
224 	if (S_ISREG(vnode->vfs_inode.i_mode))
225 		invalidate_remote_inode(&vnode->vfs_inode);
226 	else
227 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
228 }
229 
230 /*
231  * validate a vnode/inode
232  * - there are several things we need to check
233  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
234  *     symlink)
235  *   - parent dir metadata changed (security changes)
236  *   - dentry data changed (write, truncate)
237  *   - dentry metadata changed (security changes)
238  */
239 int afs_validate(struct afs_vnode *vnode, struct key *key)
240 {
241 	int ret;
242 
243 	_enter("{v={%x:%u} fl=%lx},%x",
244 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
245 	       key_serial(key));
246 
247 	if (vnode->cb_promised &&
248 	    !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
249 	    !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
250 	    !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
251 		if (vnode->cb_expires < get_seconds() + 10) {
252 			_debug("callback expired");
253 			set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
254 		} else {
255 			goto valid;
256 		}
257 	}
258 
259 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
260 		goto valid;
261 
262 	mutex_lock(&vnode->validate_lock);
263 
264 	/* if the promise has expired, we need to check the server again to get
265 	 * a new promise - note that if the (parent) directory's metadata was
266 	 * changed then the security may be different and we may no longer have
267 	 * access */
268 	if (!vnode->cb_promised ||
269 	    test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
270 		_debug("not promised");
271 		ret = afs_vnode_fetch_status(vnode, NULL, key);
272 		if (ret < 0)
273 			goto error_unlock;
274 		_debug("new promise [fl=%lx]", vnode->flags);
275 	}
276 
277 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
278 		_debug("file already deleted");
279 		ret = -ESTALE;
280 		goto error_unlock;
281 	}
282 
283 	/* if the vnode's data version number changed then its contents are
284 	 * different */
285 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
286 		afs_zap_data(vnode);
287 
288 	clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
289 	mutex_unlock(&vnode->validate_lock);
290 valid:
291 	_leave(" = 0");
292 	return 0;
293 
294 error_unlock:
295 	mutex_unlock(&vnode->validate_lock);
296 	_leave(" = %d", ret);
297 	return ret;
298 }
299 
300 /*
301  * read the attributes of an inode
302  */
303 int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
304 		      struct kstat *stat)
305 {
306 	struct inode *inode;
307 
308 	inode = dentry->d_inode;
309 
310 	_enter("{ ino=%lu v=%llu }", inode->i_ino,
311 		(unsigned long long)inode->i_version);
312 
313 	generic_fillattr(inode, stat);
314 	return 0;
315 }
316 
317 /*
318  * clear an AFS inode
319  */
320 void afs_clear_inode(struct inode *inode)
321 {
322 	struct afs_permits *permits;
323 	struct afs_vnode *vnode;
324 
325 	vnode = AFS_FS_I(inode);
326 
327 	_enter("{%x:%u.%d} v=%u x=%u t=%u }",
328 	       vnode->fid.vid,
329 	       vnode->fid.vnode,
330 	       vnode->fid.unique,
331 	       vnode->cb_version,
332 	       vnode->cb_expiry,
333 	       vnode->cb_type);
334 
335 	_debug("CLEAR INODE %p", inode);
336 
337 	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
338 
339 	afs_give_up_callback(vnode);
340 
341 	if (vnode->server) {
342 		spin_lock(&vnode->server->fs_lock);
343 		rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
344 		spin_unlock(&vnode->server->fs_lock);
345 		afs_put_server(vnode->server);
346 		vnode->server = NULL;
347 	}
348 
349 	ASSERT(list_empty(&vnode->writebacks));
350 	ASSERT(!vnode->cb_promised);
351 
352 #ifdef CONFIG_AFS_FSCACHE
353 	fscache_relinquish_cookie(vnode->cache, 0);
354 	vnode->cache = NULL;
355 #endif
356 
357 	mutex_lock(&vnode->permits_lock);
358 	permits = vnode->permits;
359 	rcu_assign_pointer(vnode->permits, NULL);
360 	mutex_unlock(&vnode->permits_lock);
361 	if (permits)
362 		call_rcu(&permits->rcu, afs_zap_permits);
363 
364 	_leave("");
365 }
366 
367 /*
368  * set the attributes of an inode
369  */
370 int afs_setattr(struct dentry *dentry, struct iattr *attr)
371 {
372 	struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
373 	struct key *key;
374 	int ret;
375 
376 	_enter("{%x:%u},{n=%s},%x",
377 	       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
378 	       attr->ia_valid);
379 
380 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
381 				ATTR_MTIME))) {
382 		_leave(" = 0 [unsupported]");
383 		return 0;
384 	}
385 
386 	/* flush any dirty data outstanding on a regular file */
387 	if (S_ISREG(vnode->vfs_inode.i_mode)) {
388 		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
389 		afs_writeback_all(vnode);
390 	}
391 
392 	if (attr->ia_valid & ATTR_FILE) {
393 		key = attr->ia_file->private_data;
394 	} else {
395 		key = afs_request_key(vnode->volume->cell);
396 		if (IS_ERR(key)) {
397 			ret = PTR_ERR(key);
398 			goto error;
399 		}
400 	}
401 
402 	ret = afs_vnode_setattr(vnode, key, attr);
403 	if (!(attr->ia_valid & ATTR_FILE))
404 		key_put(key);
405 
406 error:
407 	_leave(" = %d", ret);
408 	return ret;
409 }
410