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;
16 * Insert a volume into a cell. If there's an existing volume record, that is
17 * returned instead with a ref held.
19 static struct afs_volume *afs_insert_volume_into_cell(struct afs_cell *cell,
20 struct afs_volume *volume)
23 struct rb_node *parent = NULL, **pp;
25 write_seqlock(&cell->volume_lock);
27 pp = &cell->volumes.rb_node;
30 p = rb_entry(parent, struct afs_volume, cell_node);
31 if (p->vid < volume->vid) {
33 } else if (p->vid > volume->vid) {
34 pp = &(*pp)->rb_right;
36 volume = afs_get_volume(p, afs_volume_trace_get_cell_insert);
41 rb_link_node_rcu(&volume->cell_node, parent, pp);
42 rb_insert_color(&volume->cell_node, &cell->volumes);
43 hlist_add_head_rcu(&volume->proc_link, &cell->proc_volumes);
46 write_sequnlock(&cell->volume_lock);
51 static void afs_remove_volume_from_cell(struct afs_volume *volume)
53 struct afs_cell *cell = volume->cell;
55 if (!hlist_unhashed(&volume->proc_link)) {
56 trace_afs_volume(volume->vid, atomic_read(&volume->usage),
57 afs_volume_trace_remove);
58 write_seqlock(&cell->volume_lock);
59 hlist_del_rcu(&volume->proc_link);
60 rb_erase(&volume->cell_node, &cell->volumes);
61 write_sequnlock(&cell->volume_lock);
66 * Allocate a volume record and load it up from a vldb record.
68 static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params,
69 struct afs_vldb_entry *vldb,
70 unsigned long type_mask)
72 struct afs_server_list *slist;
73 struct afs_volume *volume;
74 int ret = -ENOMEM, nr_servers = 0, i;
76 for (i = 0; i < vldb->nr_servers; i++)
77 if (vldb->fs_mask[i] & type_mask)
80 volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
84 volume->vid = vldb->vid[params->type];
85 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
86 volume->cell = afs_get_cell(params->cell, afs_cell_trace_get_vol);
87 volume->type = params->type;
88 volume->type_force = params->force;
89 volume->name_len = vldb->name_len;
91 atomic_set(&volume->usage, 1);
92 INIT_HLIST_NODE(&volume->proc_link);
93 rwlock_init(&volume->servers_lock);
94 rwlock_init(&volume->cb_v_break_lock);
95 memcpy(volume->name, vldb->name, vldb->name_len + 1);
97 slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask);
103 refcount_set(&slist->usage, 1);
104 rcu_assign_pointer(volume->servers, slist);
105 trace_afs_volume(volume->vid, 1, afs_volume_trace_alloc);
109 afs_put_cell(volume->cell, afs_cell_trace_put_vol);
116 * Look up or allocate a volume record.
118 static struct afs_volume *afs_lookup_volume(struct afs_fs_context *params,
119 struct afs_vldb_entry *vldb,
120 unsigned long type_mask)
122 struct afs_volume *candidate, *volume;
124 candidate = afs_alloc_volume(params, vldb, type_mask);
125 if (IS_ERR(candidate))
128 volume = afs_insert_volume_into_cell(params->cell, candidate);
129 if (volume != candidate)
130 afs_put_volume(params->net, candidate, afs_volume_trace_put_cell_dup);
135 * Look up a VLDB record for a volume.
137 static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell,
142 struct afs_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ);
143 struct afs_vl_cursor vc;
146 if (!afs_begin_vlserver_operation(&vc, cell, key))
147 return ERR_PTR(-ERESTARTSYS);
149 while (afs_select_vlserver(&vc)) {
150 vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz);
153 ret = afs_end_vlserver_operation(&vc);
154 return ret < 0 ? ERR_PTR(ret) : vldb;
158 * Look up a volume in the VL server and create a candidate volume record for
161 * The volume name can be one of the following:
162 * "%[cell:]volume[.]" R/W volume
163 * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
164 * or R/W (rwparent=1) volume
165 * "%[cell:]volume.readonly" R/O volume
166 * "#[cell:]volume.readonly" R/O volume
167 * "%[cell:]volume.backup" Backup volume
168 * "#[cell:]volume.backup" Backup volume
170 * The cell name is optional, and defaults to the current cell.
172 * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
174 * - Rule 1: Explicit type suffix forces access of that type or nothing
175 * (no suffix, then use Rule 2 & 3)
176 * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
178 * - Rule 3: If parent volume is R/W, then only mount R/W volume unless
179 * explicitly told otherwise
181 struct afs_volume *afs_create_volume(struct afs_fs_context *params)
183 struct afs_vldb_entry *vldb;
184 struct afs_volume *volume;
185 unsigned long type_mask = 1UL << params->type;
187 vldb = afs_vl_lookup_vldb(params->cell, params->key,
188 params->volname, params->volnamesz);
190 return ERR_CAST(vldb);
192 if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {
193 volume = ERR_PTR(vldb->error);
197 /* Make the final decision on the type we want */
198 volume = ERR_PTR(-ENOMEDIUM);
200 if (!(vldb->flags & type_mask))
202 } else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {
203 params->type = AFSVL_ROVOL;
204 } else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {
205 params->type = AFSVL_RWVOL;
210 type_mask = 1UL << params->type;
211 volume = afs_lookup_volume(params, vldb, type_mask);
219 * Destroy a volume record
221 static void afs_destroy_volume(struct afs_net *net, struct afs_volume *volume)
223 _enter("%p", volume);
225 #ifdef CONFIG_AFS_FSCACHE
226 ASSERTCMP(volume->cache, ==, NULL);
229 afs_remove_volume_from_cell(volume);
230 afs_put_serverlist(net, rcu_access_pointer(volume->servers));
231 afs_put_cell(volume->cell, afs_cell_trace_put_vol);
232 trace_afs_volume(volume->vid, atomic_read(&volume->usage),
233 afs_volume_trace_free);
234 kfree_rcu(volume, rcu);
236 _leave(" [destroyed]");
240 * Get a reference on a volume record.
242 struct afs_volume *afs_get_volume(struct afs_volume *volume,
243 enum afs_volume_trace reason)
246 int u = atomic_inc_return(&volume->usage);
247 trace_afs_volume(volume->vid, u, reason);
254 * Drop a reference on a volume record.
256 void afs_put_volume(struct afs_net *net, struct afs_volume *volume,
257 enum afs_volume_trace reason)
260 afs_volid_t vid = volume->vid;
261 int u = atomic_dec_return(&volume->usage);
262 trace_afs_volume(vid, u, reason);
264 afs_destroy_volume(net, volume);
271 void afs_activate_volume(struct afs_volume *volume)
273 #ifdef CONFIG_AFS_FSCACHE
274 volume->cache = fscache_acquire_cookie(volume->cell->cache,
275 &afs_volume_cache_index_def,
276 &volume->vid, sizeof(volume->vid),
283 * Deactivate a volume.
285 void afs_deactivate_volume(struct afs_volume *volume)
287 _enter("%s", volume->name);
289 #ifdef CONFIG_AFS_FSCACHE
290 fscache_relinquish_cookie(volume->cache, NULL,
291 test_bit(AFS_VOLUME_DELETED, &volume->flags));
292 volume->cache = NULL;
299 * Query the VL service to update the volume status.
301 static int afs_update_volume_status(struct afs_volume *volume, struct key *key)
303 struct afs_server_list *new, *old, *discard;
304 struct afs_vldb_entry *vldb;
310 /* We look up an ID by passing it as a decimal string in the
311 * operation's name parameter.
313 idsz = sprintf(idbuf, "%llu", volume->vid);
315 vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);
321 /* See if the volume got renamed. */
322 if (vldb->name_len != volume->name_len ||
323 memcmp(vldb->name, volume->name, vldb->name_len) != 0) {
324 /* TODO: Use RCU'd string. */
325 memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);
326 volume->name_len = vldb->name_len;
329 /* See if the volume's server list got updated. */
330 new = afs_alloc_server_list(volume->cell, key,
331 vldb, (1 << volume->type));
337 write_lock(&volume->servers_lock);
340 old = rcu_dereference_protected(volume->servers,
341 lockdep_is_held(&volume->servers_lock));
342 if (afs_annotate_server_list(new, old)) {
343 new->seq = volume->servers_seq + 1;
344 rcu_assign_pointer(volume->servers, new);
346 volume->servers_seq++;
350 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
351 write_unlock(&volume->servers_lock);
354 afs_put_serverlist(volume->cell->net, discard);
358 _leave(" = %d", ret);
363 * Make sure the volume record is up to date.
365 int afs_check_volume_status(struct afs_volume *volume, struct afs_operation *op)
367 int ret, retries = 0;
372 if (test_bit(AFS_VOLUME_WAIT, &volume->flags))
374 if (volume->update_at <= ktime_get_real_seconds() ||
375 test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags))
381 if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
382 clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
383 ret = afs_update_volume_status(volume, op->key);
385 set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
386 clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);
387 clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);
388 wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);
389 _leave(" = %d", ret);
394 if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
395 _leave(" = 0 [no wait]");
399 ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT,
400 (op->flags & AFS_OPERATION_UNINTR) ?
401 TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
402 if (ret == -ERESTARTSYS) {
403 _leave(" = %d", ret);
409 _leave(" = -ESTALE");