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 rwlock_init(&volume->cb_v_break_lock);
51 memcpy(volume->name, vldb->name, vldb->name_len + 1);
52
53 slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask);
54 if (IS_ERR(slist)) {
55 ret = PTR_ERR(slist);
56 goto error_1;
57 }
58
59 refcount_set(&slist->usage, 1);
60 volume->servers = slist;
61 return volume;
62
63 error_1:
64 afs_put_cell(params->net, volume->cell);
65 kfree(volume);
66 error_0:
67 return ERR_PTR(ret);
68 }
69
70 /*
71 * Look up a VLDB record for a volume.
72 */
afs_vl_lookup_vldb(struct afs_cell * cell,struct key * key,const char * volname,size_t volnamesz)73 static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell,
74 struct key *key,
75 const char *volname,
76 size_t volnamesz)
77 {
78 struct afs_addr_cursor ac;
79 struct afs_vldb_entry *vldb;
80 int ret;
81
82 ret = afs_set_vl_cursor(&ac, cell);
83 if (ret < 0)
84 return ERR_PTR(ret);
85
86 while (afs_iterate_addresses(&ac)) {
87 if (!test_bit(ac.index, &ac.alist->probed)) {
88 ret = afs_vl_get_capabilities(cell->net, &ac, key);
89 switch (ret) {
90 case VL_SERVICE:
91 clear_bit(ac.index, &ac.alist->yfs);
92 set_bit(ac.index, &ac.alist->probed);
93 ac.addr->srx_service = ret;
94 break;
95 case YFS_VL_SERVICE:
96 set_bit(ac.index, &ac.alist->yfs);
97 set_bit(ac.index, &ac.alist->probed);
98 ac.addr->srx_service = ret;
99 break;
100 }
101 }
102
103 vldb = afs_vl_get_entry_by_name_u(cell->net, &ac, key,
104 volname, volnamesz);
105 switch (ac.error) {
106 case 0:
107 afs_end_cursor(&ac);
108 return vldb;
109 case -ECONNABORTED:
110 ac.error = afs_abort_to_error(ac.abort_code);
111 goto error;
112 case -ENOMEM:
113 case -ENONET:
114 goto error;
115 case -ENETUNREACH:
116 case -EHOSTUNREACH:
117 case -ECONNREFUSED:
118 break;
119 default:
120 ac.error = -EIO;
121 goto error;
122 }
123 }
124
125 error:
126 return ERR_PTR(afs_end_cursor(&ac));
127 }
128
129 /*
130 * Look up a volume in the VL server and create a candidate volume record for
131 * it.
132 *
133 * The volume name can be one of the following:
134 * "%[cell:]volume[.]" R/W volume
135 * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
136 * or R/W (rwparent=1) volume
137 * "%[cell:]volume.readonly" R/O volume
138 * "#[cell:]volume.readonly" R/O volume
139 * "%[cell:]volume.backup" Backup volume
140 * "#[cell:]volume.backup" Backup volume
141 *
142 * The cell name is optional, and defaults to the current cell.
143 *
144 * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
145 * Guide
146 * - Rule 1: Explicit type suffix forces access of that type or nothing
147 * (no suffix, then use Rule 2 & 3)
148 * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
149 * if not available
150 * - Rule 3: If parent volume is R/W, then only mount R/W volume unless
151 * explicitly told otherwise
152 */
afs_create_volume(struct afs_mount_params * params)153 struct afs_volume *afs_create_volume(struct afs_mount_params *params)
154 {
155 struct afs_vldb_entry *vldb;
156 struct afs_volume *volume;
157 unsigned long type_mask = 1UL << params->type;
158
159 vldb = afs_vl_lookup_vldb(params->cell, params->key,
160 params->volname, params->volnamesz);
161 if (IS_ERR(vldb))
162 return ERR_CAST(vldb);
163
164 if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {
165 volume = ERR_PTR(vldb->error);
166 goto error;
167 }
168
169 /* Make the final decision on the type we want */
170 volume = ERR_PTR(-ENOMEDIUM);
171 if (params->force) {
172 if (!(vldb->flags & type_mask))
173 goto error;
174 } else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {
175 params->type = AFSVL_ROVOL;
176 } else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {
177 params->type = AFSVL_RWVOL;
178 } else {
179 goto error;
180 }
181
182 type_mask = 1UL << params->type;
183 volume = afs_alloc_volume(params, vldb, type_mask);
184
185 error:
186 kfree(vldb);
187 return volume;
188 }
189
190 /*
191 * Destroy a volume record
192 */
afs_destroy_volume(struct afs_net * net,struct afs_volume * volume)193 static void afs_destroy_volume(struct afs_net *net, struct afs_volume *volume)
194 {
195 _enter("%p", volume);
196
197 #ifdef CONFIG_AFS_FSCACHE
198 ASSERTCMP(volume->cache, ==, NULL);
199 #endif
200
201 afs_put_serverlist(net, volume->servers);
202 afs_put_cell(net, volume->cell);
203 kfree(volume);
204
205 _leave(" [destroyed]");
206 }
207
208 /*
209 * Drop a reference on a volume record.
210 */
afs_put_volume(struct afs_cell * cell,struct afs_volume * volume)211 void afs_put_volume(struct afs_cell *cell, struct afs_volume *volume)
212 {
213 if (volume) {
214 _enter("%s", volume->name);
215
216 if (atomic_dec_and_test(&volume->usage))
217 afs_destroy_volume(cell->net, volume);
218 }
219 }
220
221 /*
222 * Activate a volume.
223 */
afs_activate_volume(struct afs_volume * volume)224 void afs_activate_volume(struct afs_volume *volume)
225 {
226 #ifdef CONFIG_AFS_FSCACHE
227 volume->cache = fscache_acquire_cookie(volume->cell->cache,
228 &afs_volume_cache_index_def,
229 &volume->vid, sizeof(volume->vid),
230 NULL, 0,
231 volume, 0, true);
232 #endif
233
234 write_lock(&volume->cell->proc_lock);
235 list_add_tail(&volume->proc_link, &volume->cell->proc_volumes);
236 write_unlock(&volume->cell->proc_lock);
237 }
238
239 /*
240 * Deactivate a volume.
241 */
afs_deactivate_volume(struct afs_volume * volume)242 void afs_deactivate_volume(struct afs_volume *volume)
243 {
244 _enter("%s", volume->name);
245
246 write_lock(&volume->cell->proc_lock);
247 list_del_init(&volume->proc_link);
248 write_unlock(&volume->cell->proc_lock);
249
250 #ifdef CONFIG_AFS_FSCACHE
251 fscache_relinquish_cookie(volume->cache, NULL,
252 test_bit(AFS_VOLUME_DELETED, &volume->flags));
253 volume->cache = NULL;
254 #endif
255
256 _leave("");
257 }
258
259 /*
260 * Query the VL service to update the volume status.
261 */
afs_update_volume_status(struct afs_volume * volume,struct key * key)262 static int afs_update_volume_status(struct afs_volume *volume, struct key *key)
263 {
264 struct afs_server_list *new, *old, *discard;
265 struct afs_vldb_entry *vldb;
266 char idbuf[16];
267 int ret, idsz;
268
269 _enter("");
270
271 /* We look up an ID by passing it as a decimal string in the
272 * operation's name parameter.
273 */
274 idsz = sprintf(idbuf, "%u", volume->vid);
275
276 vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);
277 if (IS_ERR(vldb)) {
278 ret = PTR_ERR(vldb);
279 goto error;
280 }
281
282 /* See if the volume got renamed. */
283 if (vldb->name_len != volume->name_len ||
284 memcmp(vldb->name, volume->name, vldb->name_len) != 0) {
285 /* TODO: Use RCU'd string. */
286 memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);
287 volume->name_len = vldb->name_len;
288 }
289
290 /* See if the volume's server list got updated. */
291 new = afs_alloc_server_list(volume->cell, key,
292 vldb, (1 << volume->type));
293 if (IS_ERR(new)) {
294 ret = PTR_ERR(new);
295 goto error_vldb;
296 }
297
298 write_lock(&volume->servers_lock);
299
300 discard = new;
301 old = volume->servers;
302 if (afs_annotate_server_list(new, old)) {
303 new->seq = volume->servers_seq + 1;
304 volume->servers = new;
305 smp_wmb();
306 volume->servers_seq++;
307 discard = old;
308 }
309
310 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
311 clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
312 write_unlock(&volume->servers_lock);
313 ret = 0;
314
315 afs_put_serverlist(volume->cell->net, discard);
316 error_vldb:
317 kfree(vldb);
318 error:
319 _leave(" = %d", ret);
320 return ret;
321 }
322
323 /*
324 * Make sure the volume record is up to date.
325 */
afs_check_volume_status(struct afs_volume * volume,struct key * key)326 int afs_check_volume_status(struct afs_volume *volume, struct key *key)
327 {
328 time64_t now = ktime_get_real_seconds();
329 int ret, retries = 0;
330
331 _enter("");
332
333 if (volume->update_at <= now)
334 set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
335
336 retry:
337 if (!test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags) &&
338 !test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
339 _leave(" = 0");
340 return 0;
341 }
342
343 if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
344 ret = afs_update_volume_status(volume, key);
345 clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);
346 clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);
347 wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);
348 _leave(" = %d", ret);
349 return ret;
350 }
351
352 if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
353 _leave(" = 0 [no wait]");
354 return 0;
355 }
356
357 ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT, TASK_INTERRUPTIBLE);
358 if (ret == -ERESTARTSYS) {
359 _leave(" = %d", ret);
360 return ret;
361 }
362
363 retries++;
364 if (retries == 4) {
365 _leave(" = -ESTALE");
366 return -ESTALE;
367 }
368 goto retry;
369 }
370