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
25struct 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 */
33static 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 */
92static 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 */
103static 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 */
119struct 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 */
198bad_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 */
211void 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 */
233int 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);
284valid:
285	_leave(" = 0");
286	return 0;
287
288error_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 */
297int 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=%lu }", inode->i_ino, inode->i_version);
305
306	generic_fillattr(inode, stat);
307	return 0;
308}
309
310/*
311 * clear an AFS inode
312 */
313void afs_clear_inode(struct inode *inode)
314{
315	struct afs_permits *permits;
316	struct afs_vnode *vnode;
317
318	vnode = AFS_FS_I(inode);
319
320	_enter("{%x:%u.%d} v=%u x=%u t=%u }",
321	       vnode->fid.vid,
322	       vnode->fid.vnode,
323	       vnode->fid.unique,
324	       vnode->cb_version,
325	       vnode->cb_expiry,
326	       vnode->cb_type);
327
328	_debug("CLEAR INODE %p", inode);
329
330	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
331
332	afs_give_up_callback(vnode);
333
334	if (vnode->server) {
335		spin_lock(&vnode->server->fs_lock);
336		rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
337		spin_unlock(&vnode->server->fs_lock);
338		afs_put_server(vnode->server);
339		vnode->server = NULL;
340	}
341
342	ASSERT(list_empty(&vnode->writebacks));
343	ASSERT(!vnode->cb_promised);
344
345#ifdef AFS_CACHING_SUPPORT
346	cachefs_relinquish_cookie(vnode->cache, 0);
347	vnode->cache = NULL;
348#endif
349
350	mutex_lock(&vnode->permits_lock);
351	permits = vnode->permits;
352	rcu_assign_pointer(vnode->permits, NULL);
353	mutex_unlock(&vnode->permits_lock);
354	if (permits)
355		call_rcu(&permits->rcu, afs_zap_permits);
356
357	_leave("");
358}
359
360/*
361 * set the attributes of an inode
362 */
363int afs_setattr(struct dentry *dentry, struct iattr *attr)
364{
365	struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
366	struct key *key;
367	int ret;
368
369	_enter("{%x:%u},{n=%s},%x",
370	       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
371	       attr->ia_valid);
372
373	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
374				ATTR_MTIME))) {
375		_leave(" = 0 [unsupported]");
376		return 0;
377	}
378
379	/* flush any dirty data outstanding on a regular file */
380	if (S_ISREG(vnode->vfs_inode.i_mode)) {
381		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
382		afs_writeback_all(vnode);
383	}
384
385	if (attr->ia_valid & ATTR_FILE) {
386		key = attr->ia_file->private_data;
387	} else {
388		key = afs_request_key(vnode->volume->cell);
389		if (IS_ERR(key)) {
390			ret = PTR_ERR(key);
391			goto error;
392		}
393	}
394
395	ret = afs_vnode_setattr(vnode, key, attr);
396	if (!(attr->ia_valid & ATTR_FILE))
397		key_put(key);
398
399error:
400	_leave(" = %d", ret);
401	return ret;
402}
403