xref: /openbmc/linux/fs/afs/inode.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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@cambridge.redhat.com>
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 "internal.h"
23 
24 struct afs_iget_data {
25 	struct afs_fid		fid;
26 	struct afs_volume	*volume;	/* volume on which resides */
27 };
28 
29 /*
30  * map the AFS file status to the inode member variables
31  */
32 static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
33 {
34 	struct inode *inode = AFS_VNODE_TO_I(vnode);
35 
36 	_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
37 	       vnode->status.type,
38 	       vnode->status.nlink,
39 	       (unsigned long long) vnode->status.size,
40 	       vnode->status.data_version,
41 	       vnode->status.mode);
42 
43 	switch (vnode->status.type) {
44 	case AFS_FTYPE_FILE:
45 		inode->i_mode	= S_IFREG | vnode->status.mode;
46 		inode->i_op	= &afs_file_inode_operations;
47 		inode->i_fop	= &afs_file_operations;
48 		break;
49 	case AFS_FTYPE_DIR:
50 		inode->i_mode	= S_IFDIR | vnode->status.mode;
51 		inode->i_op	= &afs_dir_inode_operations;
52 		inode->i_fop	= &afs_dir_file_operations;
53 		break;
54 	case AFS_FTYPE_SYMLINK:
55 		inode->i_mode	= S_IFLNK | vnode->status.mode;
56 		inode->i_op	= &page_symlink_inode_operations;
57 		break;
58 	default:
59 		printk("kAFS: AFS vnode with undefined type\n");
60 		return -EBADMSG;
61 	}
62 
63 	inode->i_nlink		= vnode->status.nlink;
64 	inode->i_uid		= vnode->status.owner;
65 	inode->i_gid		= 0;
66 	inode->i_size		= vnode->status.size;
67 	inode->i_ctime.tv_sec	= vnode->status.mtime_server;
68 	inode->i_ctime.tv_nsec	= 0;
69 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
70 	inode->i_blocks		= 0;
71 	inode->i_version	= vnode->fid.unique;
72 	inode->i_mapping->a_ops	= &afs_fs_aops;
73 
74 	/* check to see whether a symbolic link is really a mountpoint */
75 	if (vnode->status.type == AFS_FTYPE_SYMLINK) {
76 		afs_mntpt_check_symlink(vnode, key);
77 
78 		if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
79 			inode->i_mode	= S_IFDIR | vnode->status.mode;
80 			inode->i_op	= &afs_mntpt_inode_operations;
81 			inode->i_fop	= &afs_mntpt_file_operations;
82 		}
83 	}
84 
85 	return 0;
86 }
87 
88 /*
89  * iget5() comparator
90  */
91 static int afs_iget5_test(struct inode *inode, void *opaque)
92 {
93 	struct afs_iget_data *data = opaque;
94 
95 	return inode->i_ino == data->fid.vnode &&
96 		inode->i_version == data->fid.unique;
97 }
98 
99 /*
100  * iget5() inode initialiser
101  */
102 static int afs_iget5_set(struct inode *inode, void *opaque)
103 {
104 	struct afs_iget_data *data = opaque;
105 	struct afs_vnode *vnode = AFS_FS_I(inode);
106 
107 	inode->i_ino = data->fid.vnode;
108 	inode->i_version = data->fid.unique;
109 	vnode->fid = data->fid;
110 	vnode->volume = data->volume;
111 
112 	return 0;
113 }
114 
115 /*
116  * inode retrieval
117  */
118 struct inode *afs_iget(struct super_block *sb, struct key *key,
119 		       struct afs_fid *fid, struct afs_file_status *status,
120 		       struct afs_callback *cb)
121 {
122 	struct afs_iget_data data = { .fid = *fid };
123 	struct afs_super_info *as;
124 	struct afs_vnode *vnode;
125 	struct inode *inode;
126 	int ret;
127 
128 	_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
129 
130 	as = sb->s_fs_info;
131 	data.volume = as->volume;
132 
133 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
134 			     &data);
135 	if (!inode) {
136 		_leave(" = -ENOMEM");
137 		return ERR_PTR(-ENOMEM);
138 	}
139 
140 	_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
141 	       inode, fid->vid, fid->vnode, fid->unique);
142 
143 	vnode = AFS_FS_I(inode);
144 
145 	/* deal with an existing inode */
146 	if (!(inode->i_state & I_NEW)) {
147 		_leave(" = %p", inode);
148 		return inode;
149 	}
150 
151 #ifdef AFS_CACHING_SUPPORT
152 	/* set up caching before reading the status, as fetch-status reads the
153 	 * first page of symlinks to see if they're really mntpts */
154 	cachefs_acquire_cookie(vnode->volume->cache,
155 			       NULL,
156 			       vnode,
157 			       &vnode->cache);
158 #endif
159 
160 	if (!status) {
161 		/* it's a remotely extant inode */
162 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
163 		ret = afs_vnode_fetch_status(vnode, NULL, key);
164 		if (ret < 0)
165 			goto bad_inode;
166 	} else {
167 		/* it's an inode we just created */
168 		memcpy(&vnode->status, status, sizeof(vnode->status));
169 
170 		if (!cb) {
171 			/* it's a symlink we just created (the fileserver
172 			 * didn't give us a callback) */
173 			vnode->cb_version = 0;
174 			vnode->cb_expiry = 0;
175 			vnode->cb_type = 0;
176 			vnode->cb_expires = get_seconds();
177 		} else {
178 			vnode->cb_version = cb->version;
179 			vnode->cb_expiry = cb->expiry;
180 			vnode->cb_type = cb->type;
181 			vnode->cb_expires = vnode->cb_expiry + get_seconds();
182 		}
183 	}
184 
185 	ret = afs_inode_map_status(vnode, key);
186 	if (ret < 0)
187 		goto bad_inode;
188 
189 	/* success */
190 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
191 	inode->i_flags |= S_NOATIME;
192 	unlock_new_inode(inode);
193 	_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
194 	return inode;
195 
196 	/* failure */
197 bad_inode:
198 	make_bad_inode(inode);
199 	unlock_new_inode(inode);
200 	iput(inode);
201 
202 	_leave(" = %d [bad]", ret);
203 	return ERR_PTR(ret);
204 }
205 
206 /*
207  * mark the data attached to an inode as obsolete due to a write on the server
208  * - might also want to ditch all the outstanding writes and dirty pages
209  */
210 void afs_zap_data(struct afs_vnode *vnode)
211 {
212 	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
213 
214 	/* nuke all the non-dirty pages that aren't locked, mapped or being
215 	 * written back in a regular file and completely discard the pages in a
216 	 * directory or symlink */
217 	if (S_ISREG(vnode->vfs_inode.i_mode))
218 		invalidate_remote_inode(&vnode->vfs_inode);
219 	else
220 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
221 }
222 
223 /*
224  * validate a vnode/inode
225  * - there are several things we need to check
226  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
227  *     symlink)
228  *   - parent dir metadata changed (security changes)
229  *   - dentry data changed (write, truncate)
230  *   - dentry metadata changed (security changes)
231  */
232 int afs_validate(struct afs_vnode *vnode, struct key *key)
233 {
234 	int ret;
235 
236 	_enter("{v={%x:%u} fl=%lx},%x",
237 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
238 	       key_serial(key));
239 
240 	if (vnode->cb_promised &&
241 	    !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
242 	    !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
243 	    !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
244 		if (vnode->cb_expires < get_seconds() + 10) {
245 			_debug("callback expired");
246 			set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
247 		} else {
248 			goto valid;
249 		}
250 	}
251 
252 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
253 		goto valid;
254 
255 	mutex_lock(&vnode->validate_lock);
256 
257 	/* if the promise has expired, we need to check the server again to get
258 	 * a new promise - note that if the (parent) directory's metadata was
259 	 * changed then the security may be different and we may no longer have
260 	 * access */
261 	if (!vnode->cb_promised ||
262 	    test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
263 		_debug("not promised");
264 		ret = afs_vnode_fetch_status(vnode, NULL, key);
265 		if (ret < 0)
266 			goto error_unlock;
267 		_debug("new promise [fl=%lx]", vnode->flags);
268 	}
269 
270 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
271 		_debug("file already deleted");
272 		ret = -ESTALE;
273 		goto error_unlock;
274 	}
275 
276 	/* if the vnode's data version number changed then its contents are
277 	 * different */
278 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
279 		afs_zap_data(vnode);
280 
281 	clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
282 	mutex_unlock(&vnode->validate_lock);
283 valid:
284 	_leave(" = 0");
285 	return 0;
286 
287 error_unlock:
288 	mutex_unlock(&vnode->validate_lock);
289 	_leave(" = %d", ret);
290 	return ret;
291 }
292 
293 /*
294  * read the attributes of an inode
295  */
296 int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
297 		      struct kstat *stat)
298 {
299 	struct inode *inode;
300 
301 	inode = dentry->d_inode;
302 
303 	_enter("{ ino=%lu v=%lu }", inode->i_ino, inode->i_version);
304 
305 	generic_fillattr(inode, stat);
306 	return 0;
307 }
308 
309 /*
310  * clear an AFS inode
311  */
312 void afs_clear_inode(struct inode *inode)
313 {
314 	struct afs_permits *permits;
315 	struct afs_vnode *vnode;
316 
317 	vnode = AFS_FS_I(inode);
318 
319 	_enter("{%x:%u.%d} v=%u x=%u t=%u }",
320 	       vnode->fid.vid,
321 	       vnode->fid.vnode,
322 	       vnode->fid.unique,
323 	       vnode->cb_version,
324 	       vnode->cb_expiry,
325 	       vnode->cb_type);
326 
327 	_debug("CLEAR INODE %p", inode);
328 
329 	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
330 
331 	afs_give_up_callback(vnode);
332 
333 	if (vnode->server) {
334 		spin_lock(&vnode->server->fs_lock);
335 		rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
336 		spin_unlock(&vnode->server->fs_lock);
337 		afs_put_server(vnode->server);
338 		vnode->server = NULL;
339 	}
340 
341 	ASSERT(list_empty(&vnode->writebacks));
342 	ASSERT(!vnode->cb_promised);
343 
344 #ifdef AFS_CACHING_SUPPORT
345 	cachefs_relinquish_cookie(vnode->cache, 0);
346 	vnode->cache = NULL;
347 #endif
348 
349 	mutex_lock(&vnode->permits_lock);
350 	permits = vnode->permits;
351 	rcu_assign_pointer(vnode->permits, NULL);
352 	mutex_unlock(&vnode->permits_lock);
353 	if (permits)
354 		call_rcu(&permits->rcu, afs_zap_permits);
355 
356 	_leave("");
357 }
358 
359 /*
360  * set the attributes of an inode
361  */
362 int afs_setattr(struct dentry *dentry, struct iattr *attr)
363 {
364 	struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
365 	struct key *key;
366 	int ret;
367 
368 	_enter("{%x:%u},{n=%s},%x",
369 	       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
370 	       attr->ia_valid);
371 
372 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
373 				ATTR_MTIME))) {
374 		_leave(" = 0 [unsupported]");
375 		return 0;
376 	}
377 
378 	/* flush any dirty data outstanding on a regular file */
379 	if (S_ISREG(vnode->vfs_inode.i_mode)) {
380 		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
381 		afs_writeback_all(vnode);
382 	}
383 
384 	if (attr->ia_valid & ATTR_FILE) {
385 		key = attr->ia_file->private_data;
386 	} else {
387 		key = afs_request_key(vnode->volume->cell);
388 		if (IS_ERR(key)) {
389 			ret = PTR_ERR(key);
390 			goto error;
391 		}
392 	}
393 
394 	ret = afs_vnode_setattr(vnode, key, attr);
395 	if (!(attr->ia_valid & ATTR_FILE))
396 		key_put(key);
397 
398 error:
399 	_leave(" = %d", ret);
400 	return ret;
401 }
402