1 /* AFS volume management
2 *
3 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include "internal.h"
15
16 unsigned __read_mostly afs_volume_gc_delay = 10;
17 unsigned __read_mostly afs_volume_record_life = 60 * 60;
18
19 static const char *const afs_voltypes[] = { "R/W", "R/O", "BAK" };
20
21 /*
22 * Allocate a volume record and load it up from a vldb record.
23 */
afs_alloc_volume(struct afs_mount_params * params,struct afs_vldb_entry * vldb,unsigned long type_mask)24 static struct afs_volume *afs_alloc_volume(struct afs_mount_params *params,
25 struct afs_vldb_entry *vldb,
26 unsigned long type_mask)
27 {
28 struct afs_server_list *slist;
29 struct afs_volume *volume;
30 int ret = -ENOMEM, nr_servers = 0, i;
31
32 for (i = 0; i < vldb->nr_servers; i++)
33 if (vldb->fs_mask[i] & type_mask)
34 nr_servers++;
35
36 volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
37 if (!volume)
38 goto error_0;
39
40 volume->vid = vldb->vid[params->type];
41 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
42 volume->cell = afs_get_cell(params->cell);
43 volume->type = params->type;
44 volume->type_force = params->force;
45 volume->name_len = vldb->name_len;
46
47 atomic_set(&volume->usage, 1);
48 INIT_LIST_HEAD(&volume->proc_link);
49 rwlock_init(&volume->servers_lock);
50 memcpy(volume->name, vldb->name, vldb->name_len + 1);
51
52 slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask);
53 if (IS_ERR(slist)) {
54 ret = PTR_ERR(slist);
55 goto error_1;
56 }
57
58 refcount_set(&slist->usage, 1);
59 volume->servers = slist;
60 return volume;
61
62 error_1:
63 afs_put_cell(params->net, volume->cell);
64 kfree(volume);
65 error_0:
66 return ERR_PTR(ret);
67 }
68
69 /*
70 * Look up a VLDB record for a volume.
71 */
afs_vl_lookup_vldb(struct afs_cell * cell,struct key * key,const char * volname,size_t volnamesz)72 static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell,
73 struct key *key,
74 const char *volname,
75 size_t volnamesz)
76 {
77 struct afs_addr_cursor ac;
78 struct afs_vldb_entry *vldb;
79 int ret;
80
81 ret = afs_set_vl_cursor(&ac, cell);
82 if (ret < 0)
83 return ERR_PTR(ret);
84
85 while (afs_iterate_addresses(&ac)) {
86 if (!test_bit(ac.index, &ac.alist->probed)) {
87 ret = afs_vl_get_capabilities(cell->net, &ac, key);
88 switch (ret) {
89 case VL_SERVICE:
90 clear_bit(ac.index, &ac.alist->yfs);
91 set_bit(ac.index, &ac.alist->probed);
92 ac.addr->srx_service = ret;
93 break;
94 case YFS_VL_SERVICE:
95 set_bit(ac.index, &ac.alist->yfs);
96 set_bit(ac.index, &ac.alist->probed);
97 ac.addr->srx_service = ret;
98 break;
99 }
100 }
101
102 vldb = afs_vl_get_entry_by_name_u(cell->net, &ac, key,
103 volname, volnamesz);
104 switch (ac.error) {
105 case 0:
106 afs_end_cursor(&ac);
107 return vldb;
108 case -ECONNABORTED:
109 ac.error = afs_abort_to_error(ac.abort_code);
110 goto error;
111 case -ENOMEM:
112 case -ENONET:
113 goto error;
114 case -ENETUNREACH:
115 case -EHOSTUNREACH:
116 case -ECONNREFUSED:
117 break;
118 default:
119 ac.error = -EIO;
120 goto error;
121 }
122 }
123
124 error:
125 return ERR_PTR(afs_end_cursor(&ac));
126 }
127
128 /*
129 * Look up a volume in the VL server and create a candidate volume record for
130 * it.
131 *
132 * The volume name can be one of the following:
133 * "%[cell:]volume[.]" R/W volume
134 * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
135 * or R/W (rwparent=1) volume
136 * "%[cell:]volume.readonly" R/O volume
137 * "#[cell:]volume.readonly" R/O volume
138 * "%[cell:]volume.backup" Backup volume
139 * "#[cell:]volume.backup" Backup volume
140 *
141 * The cell name is optional, and defaults to the current cell.
142 *
143 * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
144 * Guide
145 * - Rule 1: Explicit type suffix forces access of that type or nothing
146 * (no suffix, then use Rule 2 & 3)
147 * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
148 * if not available
149 * - Rule 3: If parent volume is R/W, then only mount R/W volume unless
150 * explicitly told otherwise
151 */
afs_create_volume(struct afs_mount_params * params)152 struct afs_volume *afs_create_volume(struct afs_mount_params *params)
153 {
154 struct afs_vldb_entry *vldb;
155 struct afs_volume *volume;
156 unsigned long type_mask = 1UL << params->type;
157
158 vldb = afs_vl_lookup_vldb(params->cell, params->key,
159 params->volname, params->volnamesz);
160 if (IS_ERR(vldb))
161 return ERR_CAST(vldb);
162
163 if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {
164 volume = ERR_PTR(vldb->error);
165 goto error;
166 }
167
168 /* Make the final decision on the type we want */
169 volume = ERR_PTR(-ENOMEDIUM);
170 if (params->force) {
171 if (!(vldb->flags & type_mask))
172 goto error;
173 } else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {
174 params->type = AFSVL_ROVOL;
175 } else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {
176 params->type = AFSVL_RWVOL;
177 } else {
178 goto error;
179 }
180
181 type_mask = 1UL << params->type;
182 volume = afs_alloc_volume(params, vldb, type_mask);
183
184 error:
185 kfree(vldb);
186 return volume;
187 }
188
189 /*
190 * Destroy a volume record
191 */
afs_destroy_volume(struct afs_net * net,struct afs_volume * volume)192 static void afs_destroy_volume(struct afs_net *net, struct afs_volume *volume)
193 {
194 _enter("%p", volume);
195
196 #ifdef CONFIG_AFS_FSCACHE
197 ASSERTCMP(volume->cache, ==, NULL);
198 #endif
199
200 afs_put_serverlist(net, volume->servers);
201 afs_put_cell(net, volume->cell);
202 kfree(volume);
203
204 _leave(" [destroyed]");
205 }
206
207 /*
208 * Drop a reference on a volume record.
209 */
afs_put_volume(struct afs_cell * cell,struct afs_volume * volume)210 void afs_put_volume(struct afs_cell *cell, struct afs_volume *volume)
211 {
212 if (volume) {
213 _enter("%s", volume->name);
214
215 if (atomic_dec_and_test(&volume->usage))
216 afs_destroy_volume(cell->net, volume);
217 }
218 }
219
220 /*
221 * Activate a volume.
222 */
afs_activate_volume(struct afs_volume * volume)223 void afs_activate_volume(struct afs_volume *volume)
224 {
225 #ifdef CONFIG_AFS_FSCACHE
226 volume->cache = fscache_acquire_cookie(volume->cell->cache,
227 &afs_volume_cache_index_def,
228 &volume->vid, sizeof(volume->vid),
229 NULL, 0,
230 volume, 0, true);
231 #endif
232
233 write_lock(&volume->cell->proc_lock);
234 list_add_tail(&volume->proc_link, &volume->cell->proc_volumes);
235 write_unlock(&volume->cell->proc_lock);
236 }
237
238 /*
239 * Deactivate a volume.
240 */
afs_deactivate_volume(struct afs_volume * volume)241 void afs_deactivate_volume(struct afs_volume *volume)
242 {
243 _enter("%s", volume->name);
244
245 write_lock(&volume->cell->proc_lock);
246 list_del_init(&volume->proc_link);
247 write_unlock(&volume->cell->proc_lock);
248
249 #ifdef CONFIG_AFS_FSCACHE
250 fscache_relinquish_cookie(volume->cache, NULL,
251 test_bit(AFS_VOLUME_DELETED, &volume->flags));
252 volume->cache = NULL;
253 #endif
254
255 _leave("");
256 }
257
258 /*
259 * Query the VL service to update the volume status.
260 */
afs_update_volume_status(struct afs_volume * volume,struct key * key)261 static int afs_update_volume_status(struct afs_volume *volume, struct key *key)
262 {
263 struct afs_server_list *new, *old, *discard;
264 struct afs_vldb_entry *vldb;
265 char idbuf[16];
266 int ret, idsz;
267
268 _enter("");
269
270 /* We look up an ID by passing it as a decimal string in the
271 * operation's name parameter.
272 */
273 idsz = sprintf(idbuf, "%u", volume->vid);
274
275 vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);
276 if (IS_ERR(vldb)) {
277 ret = PTR_ERR(vldb);
278 goto error;
279 }
280
281 /* See if the volume got renamed. */
282 if (vldb->name_len != volume->name_len ||
283 memcmp(vldb->name, volume->name, vldb->name_len) != 0) {
284 /* TODO: Use RCU'd string. */
285 memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);
286 volume->name_len = vldb->name_len;
287 }
288
289 /* See if the volume's server list got updated. */
290 new = afs_alloc_server_list(volume->cell, key,
291 vldb, (1 << volume->type));
292 if (IS_ERR(new)) {
293 ret = PTR_ERR(new);
294 goto error_vldb;
295 }
296
297 write_lock(&volume->servers_lock);
298
299 discard = new;
300 old = volume->servers;
301 if (afs_annotate_server_list(new, old)) {
302 new->seq = volume->servers_seq + 1;
303 volume->servers = new;
304 smp_wmb();
305 volume->servers_seq++;
306 discard = old;
307 }
308
309 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
310 clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
311 write_unlock(&volume->servers_lock);
312 ret = 0;
313
314 afs_put_serverlist(volume->cell->net, discard);
315 error_vldb:
316 kfree(vldb);
317 error:
318 _leave(" = %d", ret);
319 return ret;
320 }
321
322 /*
323 * Make sure the volume record is up to date.
324 */
afs_check_volume_status(struct afs_volume * volume,struct key * key)325 int afs_check_volume_status(struct afs_volume *volume, struct key *key)
326 {
327 time64_t now = ktime_get_real_seconds();
328 int ret, retries = 0;
329
330 _enter("");
331
332 if (volume->update_at <= now)
333 set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
334
335 retry:
336 if (!test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags) &&
337 !test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
338 _leave(" = 0");
339 return 0;
340 }
341
342 if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
343 ret = afs_update_volume_status(volume, key);
344 clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);
345 clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);
346 wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);
347 _leave(" = %d", ret);
348 return ret;
349 }
350
351 if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
352 _leave(" = 0 [no wait]");
353 return 0;
354 }
355
356 ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT, TASK_INTERRUPTIBLE);
357 if (ret == -ERESTARTSYS) {
358 _leave(" = %d", ret);
359 return ret;
360 }
361
362 retries++;
363 if (retries == 4) {
364 _leave(" = -ESTALE");
365 return -ESTALE;
366 }
367 goto retry;
368 }
369
