xref: /openbmc/linux/fs/afs/inode.c (revision 643d1f7f)
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 <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 	inode->i_nlink		= vnode->status.nlink;
65 	inode->i_uid		= vnode->status.owner;
66 	inode->i_gid		= 0;
67 	inode->i_size		= vnode->status.size;
68 	inode->i_ctime.tv_sec	= vnode->status.mtime_server;
69 	inode->i_ctime.tv_nsec	= 0;
70 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
71 	inode->i_blocks		= 0;
72 	inode->i_version	= vnode->fid.unique;
73 	inode->i_mapping->a_ops	= &afs_fs_aops;
74 
75 	/* check to see whether a symbolic link is really a mountpoint */
76 	if (vnode->status.type == AFS_FTYPE_SYMLINK) {
77 		afs_mntpt_check_symlink(vnode, key);
78 
79 		if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
80 			inode->i_mode	= S_IFDIR | vnode->status.mode;
81 			inode->i_op	= &afs_mntpt_inode_operations;
82 			inode->i_fop	= &afs_mntpt_file_operations;
83 		}
84 	}
85 
86 	return 0;
87 }
88 
89 /*
90  * iget5() comparator
91  */
92 static int afs_iget5_test(struct inode *inode, void *opaque)
93 {
94 	struct afs_iget_data *data = opaque;
95 
96 	return inode->i_ino == data->fid.vnode &&
97 		inode->i_version == data->fid.unique;
98 }
99 
100 /*
101  * iget5() inode initialiser
102  */
103 static int afs_iget5_set(struct inode *inode, void *opaque)
104 {
105 	struct afs_iget_data *data = opaque;
106 	struct afs_vnode *vnode = AFS_FS_I(inode);
107 
108 	inode->i_ino = data->fid.vnode;
109 	inode->i_version = data->fid.unique;
110 	vnode->fid = data->fid;
111 	vnode->volume = data->volume;
112 
113 	return 0;
114 }
115 
116 /*
117  * inode retrieval
118  */
119 struct inode *afs_iget(struct super_block *sb, struct key *key,
120 		       struct afs_fid *fid, struct afs_file_status *status,
121 		       struct afs_callback *cb)
122 {
123 	struct afs_iget_data data = { .fid = *fid };
124 	struct afs_super_info *as;
125 	struct afs_vnode *vnode;
126 	struct inode *inode;
127 	int ret;
128 
129 	_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
130 
131 	as = sb->s_fs_info;
132 	data.volume = as->volume;
133 
134 	inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
135 			     &data);
136 	if (!inode) {
137 		_leave(" = -ENOMEM");
138 		return ERR_PTR(-ENOMEM);
139 	}
140 
141 	_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
142 	       inode, fid->vid, fid->vnode, fid->unique);
143 
144 	vnode = AFS_FS_I(inode);
145 
146 	/* deal with an existing inode */
147 	if (!(inode->i_state & I_NEW)) {
148 		_leave(" = %p", inode);
149 		return inode;
150 	}
151 
152 #ifdef AFS_CACHING_SUPPORT
153 	/* set up caching before reading the status, as fetch-status reads the
154 	 * first page of symlinks to see if they're really mntpts */
155 	cachefs_acquire_cookie(vnode->volume->cache,
156 			       NULL,
157 			       vnode,
158 			       &vnode->cache);
159 #endif
160 
161 	if (!status) {
162 		/* it's a remotely extant inode */
163 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
164 		ret = afs_vnode_fetch_status(vnode, NULL, key);
165 		if (ret < 0)
166 			goto bad_inode;
167 	} else {
168 		/* it's an inode we just created */
169 		memcpy(&vnode->status, status, sizeof(vnode->status));
170 
171 		if (!cb) {
172 			/* it's a symlink we just created (the fileserver
173 			 * didn't give us a callback) */
174 			vnode->cb_version = 0;
175 			vnode->cb_expiry = 0;
176 			vnode->cb_type = 0;
177 			vnode->cb_expires = get_seconds();
178 		} else {
179 			vnode->cb_version = cb->version;
180 			vnode->cb_expiry = cb->expiry;
181 			vnode->cb_type = cb->type;
182 			vnode->cb_expires = vnode->cb_expiry + get_seconds();
183 		}
184 	}
185 
186 	ret = afs_inode_map_status(vnode, key);
187 	if (ret < 0)
188 		goto bad_inode;
189 
190 	/* success */
191 	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
192 	inode->i_flags |= S_NOATIME;
193 	unlock_new_inode(inode);
194 	_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
195 	return inode;
196 
197 	/* failure */
198 bad_inode:
199 	make_bad_inode(inode);
200 	unlock_new_inode(inode);
201 	iput(inode);
202 
203 	_leave(" = %d [bad]", ret);
204 	return ERR_PTR(ret);
205 }
206 
207 /*
208  * mark the data attached to an inode as obsolete due to a write on the server
209  * - might also want to ditch all the outstanding writes and dirty pages
210  */
211 void afs_zap_data(struct afs_vnode *vnode)
212 {
213 	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
214 
215 	/* nuke all the non-dirty pages that aren't locked, mapped or being
216 	 * written back in a regular file and completely discard the pages in a
217 	 * directory or symlink */
218 	if (S_ISREG(vnode->vfs_inode.i_mode))
219 		invalidate_remote_inode(&vnode->vfs_inode);
220 	else
221 		invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
222 }
223 
224 /*
225  * validate a vnode/inode
226  * - there are several things we need to check
227  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
228  *     symlink)
229  *   - parent dir metadata changed (security changes)
230  *   - dentry data changed (write, truncate)
231  *   - dentry metadata changed (security changes)
232  */
233 int afs_validate(struct afs_vnode *vnode, struct key *key)
234 {
235 	int ret;
236 
237 	_enter("{v={%x:%u} fl=%lx},%x",
238 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
239 	       key_serial(key));
240 
241 	if (vnode->cb_promised &&
242 	    !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
243 	    !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
244 	    !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
245 		if (vnode->cb_expires < get_seconds() + 10) {
246 			_debug("callback expired");
247 			set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
248 		} else {
249 			goto valid;
250 		}
251 	}
252 
253 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
254 		goto valid;
255 
256 	mutex_lock(&vnode->validate_lock);
257 
258 	/* if the promise has expired, we need to check the server again to get
259 	 * a new promise - note that if the (parent) directory's metadata was
260 	 * changed then the security may be different and we may no longer have
261 	 * access */
262 	if (!vnode->cb_promised ||
263 	    test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
264 		_debug("not promised");
265 		ret = afs_vnode_fetch_status(vnode, NULL, key);
266 		if (ret < 0)
267 			goto error_unlock;
268 		_debug("new promise [fl=%lx]", vnode->flags);
269 	}
270 
271 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
272 		_debug("file already deleted");
273 		ret = -ESTALE;
274 		goto error_unlock;
275 	}
276 
277 	/* if the vnode's data version number changed then its contents are
278 	 * different */
279 	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
280 		afs_zap_data(vnode);
281 
282 	clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
283 	mutex_unlock(&vnode->validate_lock);
284 valid:
285 	_leave(" = 0");
286 	return 0;
287 
288 error_unlock:
289 	mutex_unlock(&vnode->validate_lock);
290 	_leave(" = %d", ret);
291 	return ret;
292 }
293 
294 /*
295  * read the attributes of an inode
296  */
297 int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
298 		      struct kstat *stat)
299 {
300 	struct inode *inode;
301 
302 	inode = dentry->d_inode;
303 
304 	_enter("{ ino=%lu v=%llu }", inode->i_ino,
305 		(unsigned long long)inode->i_version);
306 
307 	generic_fillattr(inode, stat);
308 	return 0;
309 }
310 
311 /*
312  * clear an AFS inode
313  */
314 void afs_clear_inode(struct inode *inode)
315 {
316 	struct afs_permits *permits;
317 	struct afs_vnode *vnode;
318 
319 	vnode = AFS_FS_I(inode);
320 
321 	_enter("{%x:%u.%d} v=%u x=%u t=%u }",
322 	       vnode->fid.vid,
323 	       vnode->fid.vnode,
324 	       vnode->fid.unique,
325 	       vnode->cb_version,
326 	       vnode->cb_expiry,
327 	       vnode->cb_type);
328 
329 	_debug("CLEAR INODE %p", inode);
330 
331 	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
332 
333 	afs_give_up_callback(vnode);
334 
335 	if (vnode->server) {
336 		spin_lock(&vnode->server->fs_lock);
337 		rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
338 		spin_unlock(&vnode->server->fs_lock);
339 		afs_put_server(vnode->server);
340 		vnode->server = NULL;
341 	}
342 
343 	ASSERT(list_empty(&vnode->writebacks));
344 	ASSERT(!vnode->cb_promised);
345 
346 #ifdef AFS_CACHING_SUPPORT
347 	cachefs_relinquish_cookie(vnode->cache, 0);
348 	vnode->cache = NULL;
349 #endif
350 
351 	mutex_lock(&vnode->permits_lock);
352 	permits = vnode->permits;
353 	rcu_assign_pointer(vnode->permits, NULL);
354 	mutex_unlock(&vnode->permits_lock);
355 	if (permits)
356 		call_rcu(&permits->rcu, afs_zap_permits);
357 
358 	_leave("");
359 }
360 
361 /*
362  * set the attributes of an inode
363  */
364 int afs_setattr(struct dentry *dentry, struct iattr *attr)
365 {
366 	struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
367 	struct key *key;
368 	int ret;
369 
370 	_enter("{%x:%u},{n=%s},%x",
371 	       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
372 	       attr->ia_valid);
373 
374 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
375 				ATTR_MTIME))) {
376 		_leave(" = 0 [unsupported]");
377 		return 0;
378 	}
379 
380 	/* flush any dirty data outstanding on a regular file */
381 	if (S_ISREG(vnode->vfs_inode.i_mode)) {
382 		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
383 		afs_writeback_all(vnode);
384 	}
385 
386 	if (attr->ia_valid & ATTR_FILE) {
387 		key = attr->ia_file->private_data;
388 	} else {
389 		key = afs_request_key(vnode->volume->cell);
390 		if (IS_ERR(key)) {
391 			ret = PTR_ERR(key);
392 			goto error;
393 		}
394 	}
395 
396 	ret = afs_vnode_setattr(vnode, key, attr);
397 	if (!(attr->ia_valid & ATTR_FILE))
398 		key_put(key);
399 
400 error:
401 	_leave(" = %d", ret);
402 	return ret;
403 }
404