1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* AFS volume management
4 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #include <linux/kernel.h>
9 #include <linux/slab.h>
12 unsigned __read_mostly afs_volume_gc_delay = 10;
13 unsigned __read_mostly afs_volume_record_life = 60 * 60;
15 static const char *const afs_voltypes[] = { "R/W", "R/O", "BAK" };
18 * Allocate a volume record and load it up from a vldb record.
20 static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params,
21 struct afs_vldb_entry *vldb,
22 unsigned long type_mask)
24 struct afs_server_list *slist;
25 struct afs_volume *volume;
26 int ret = -ENOMEM, nr_servers = 0, i;
28 for (i = 0; i < vldb->nr_servers; i++)
29 if (vldb->fs_mask[i] & type_mask)
32 volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
36 volume->vid = vldb->vid[params->type];
37 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
38 volume->cell = afs_get_cell(params->cell);
39 volume->type = params->type;
40 volume->type_force = params->force;
41 volume->name_len = vldb->name_len;
43 atomic_set(&volume->usage, 1);
44 INIT_LIST_HEAD(&volume->proc_link);
45 rwlock_init(&volume->servers_lock);
46 rwlock_init(&volume->cb_v_break_lock);
47 memcpy(volume->name, vldb->name, vldb->name_len + 1);
49 slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask);
55 refcount_set(&slist->usage, 1);
56 volume->servers = slist;
60 afs_put_cell(params->net, volume->cell);
67 * Look up a VLDB record for a volume.
69 static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell,
74 struct afs_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ);
75 struct afs_vl_cursor vc;
78 if (!afs_begin_vlserver_operation(&vc, cell, key))
79 return ERR_PTR(-ERESTARTSYS);
81 while (afs_select_vlserver(&vc)) {
82 vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz);
85 ret = afs_end_vlserver_operation(&vc);
86 return ret < 0 ? ERR_PTR(ret) : vldb;
90 * Look up a volume in the VL server and create a candidate volume record for
93 * The volume name can be one of the following:
94 * "%[cell:]volume[.]" R/W volume
95 * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
96 * or R/W (rwparent=1) volume
97 * "%[cell:]volume.readonly" R/O volume
98 * "#[cell:]volume.readonly" R/O volume
99 * "%[cell:]volume.backup" Backup volume
100 * "#[cell:]volume.backup" Backup volume
102 * The cell name is optional, and defaults to the current cell.
104 * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
106 * - Rule 1: Explicit type suffix forces access of that type or nothing
107 * (no suffix, then use Rule 2 & 3)
108 * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
110 * - Rule 3: If parent volume is R/W, then only mount R/W volume unless
111 * explicitly told otherwise
113 struct afs_volume *afs_create_volume(struct afs_fs_context *params)
115 struct afs_vldb_entry *vldb;
116 struct afs_volume *volume;
117 unsigned long type_mask = 1UL << params->type;
119 vldb = afs_vl_lookup_vldb(params->cell, params->key,
120 params->volname, params->volnamesz);
122 return ERR_CAST(vldb);
124 if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {
125 volume = ERR_PTR(vldb->error);
129 /* Make the final decision on the type we want */
130 volume = ERR_PTR(-ENOMEDIUM);
132 if (!(vldb->flags & type_mask))
134 } else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {
135 params->type = AFSVL_ROVOL;
136 } else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {
137 params->type = AFSVL_RWVOL;
142 type_mask = 1UL << params->type;
143 volume = afs_alloc_volume(params, vldb, type_mask);
151 * Destroy a volume record
153 static void afs_destroy_volume(struct afs_net *net, struct afs_volume *volume)
155 _enter("%p", volume);
157 #ifdef CONFIG_AFS_FSCACHE
158 ASSERTCMP(volume->cache, ==, NULL);
161 afs_put_serverlist(net, volume->servers);
162 afs_put_cell(net, volume->cell);
165 _leave(" [destroyed]");
169 * Drop a reference on a volume record.
171 void afs_put_volume(struct afs_cell *cell, struct afs_volume *volume)
174 _enter("%s", volume->name);
176 if (atomic_dec_and_test(&volume->usage))
177 afs_destroy_volume(cell->net, volume);
184 void afs_activate_volume(struct afs_volume *volume)
186 #ifdef CONFIG_AFS_FSCACHE
187 volume->cache = fscache_acquire_cookie(volume->cell->cache,
188 &afs_volume_cache_index_def,
189 &volume->vid, sizeof(volume->vid),
194 write_lock(&volume->cell->proc_lock);
195 list_add_tail(&volume->proc_link, &volume->cell->proc_volumes);
196 write_unlock(&volume->cell->proc_lock);
200 * Deactivate a volume.
202 void afs_deactivate_volume(struct afs_volume *volume)
204 _enter("%s", volume->name);
206 write_lock(&volume->cell->proc_lock);
207 list_del_init(&volume->proc_link);
208 write_unlock(&volume->cell->proc_lock);
210 #ifdef CONFIG_AFS_FSCACHE
211 fscache_relinquish_cookie(volume->cache, NULL,
212 test_bit(AFS_VOLUME_DELETED, &volume->flags));
213 volume->cache = NULL;
220 * Query the VL service to update the volume status.
222 static int afs_update_volume_status(struct afs_volume *volume, struct key *key)
224 struct afs_server_list *new, *old, *discard;
225 struct afs_vldb_entry *vldb;
231 /* We look up an ID by passing it as a decimal string in the
232 * operation's name parameter.
234 idsz = sprintf(idbuf, "%llu", volume->vid);
236 vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);
242 /* See if the volume got renamed. */
243 if (vldb->name_len != volume->name_len ||
244 memcmp(vldb->name, volume->name, vldb->name_len) != 0) {
245 /* TODO: Use RCU'd string. */
246 memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);
247 volume->name_len = vldb->name_len;
250 /* See if the volume's server list got updated. */
251 new = afs_alloc_server_list(volume->cell, key,
252 vldb, (1 << volume->type));
258 write_lock(&volume->servers_lock);
261 old = volume->servers;
262 if (afs_annotate_server_list(new, old)) {
263 new->seq = volume->servers_seq + 1;
264 volume->servers = new;
266 volume->servers_seq++;
270 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
271 clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
272 write_unlock(&volume->servers_lock);
275 afs_put_serverlist(volume->cell->net, discard);
279 _leave(" = %d", ret);
284 * Make sure the volume record is up to date.
286 int afs_check_volume_status(struct afs_volume *volume, struct key *key)
288 time64_t now = ktime_get_real_seconds();
289 int ret, retries = 0;
293 if (volume->update_at <= now)
294 set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
297 if (!test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags) &&
298 !test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
303 if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
304 ret = afs_update_volume_status(volume, key);
305 clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);
306 clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);
307 wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);
308 _leave(" = %d", ret);
312 if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
313 _leave(" = 0 [no wait]");
317 ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT, TASK_INTERRUPTIBLE);
318 if (ret == -ERESTARTSYS) {
319 _leave(" = %d", ret);
325 _leave(" = -ESTALE");