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 static unsigned __read_mostly afs_volume_record_life = 60 * 60;
15 * Insert a volume into a cell. If there's an existing volume record, that is
16 * returned instead with a ref held.
18 static struct afs_volume *afs_insert_volume_into_cell(struct afs_cell *cell,
19 struct afs_volume *volume)
22 struct rb_node *parent = NULL, **pp;
24 write_seqlock(&cell->volume_lock);
26 pp = &cell->volumes.rb_node;
29 p = rb_entry(parent, struct afs_volume, cell_node);
30 if (p->vid < volume->vid) {
32 } else if (p->vid > volume->vid) {
33 pp = &(*pp)->rb_right;
35 if (afs_try_get_volume(p, afs_volume_trace_get_cell_insert)) {
40 set_bit(AFS_VOLUME_RM_TREE, &volume->flags);
41 rb_replace_node_rcu(&p->cell_node, &volume->cell_node, &cell->volumes);
45 rb_link_node_rcu(&volume->cell_node, parent, pp);
46 rb_insert_color(&volume->cell_node, &cell->volumes);
47 hlist_add_head_rcu(&volume->proc_link, &cell->proc_volumes);
50 write_sequnlock(&cell->volume_lock);
55 static void afs_remove_volume_from_cell(struct afs_volume *volume)
57 struct afs_cell *cell = volume->cell;
59 if (!hlist_unhashed(&volume->proc_link)) {
60 trace_afs_volume(volume->vid, refcount_read(&cell->ref),
61 afs_volume_trace_remove);
62 write_seqlock(&cell->volume_lock);
63 hlist_del_rcu(&volume->proc_link);
64 if (!test_and_set_bit(AFS_VOLUME_RM_TREE, &volume->flags))
65 rb_erase(&volume->cell_node, &cell->volumes);
66 write_sequnlock(&cell->volume_lock);
71 * Allocate a volume record and load it up from a vldb record.
73 static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params,
74 struct afs_vldb_entry *vldb,
75 unsigned long type_mask)
77 struct afs_server_list *slist;
78 struct afs_volume *volume;
81 volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
85 volume->vid = vldb->vid[params->type];
86 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
87 volume->cell = afs_get_cell(params->cell, afs_cell_trace_get_vol);
88 volume->type = params->type;
89 volume->type_force = params->force;
90 volume->name_len = vldb->name_len;
92 refcount_set(&volume->ref, 1);
93 INIT_HLIST_NODE(&volume->proc_link);
94 rwlock_init(&volume->servers_lock);
95 rwlock_init(&volume->cb_v_break_lock);
96 memcpy(volume->name, vldb->name, vldb->name_len + 1);
98 slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask);
100 ret = PTR_ERR(slist);
104 refcount_set(&slist->usage, 1);
105 rcu_assign_pointer(volume->servers, slist);
106 trace_afs_volume(volume->vid, 1, afs_volume_trace_alloc);
110 afs_put_cell(volume->cell, afs_cell_trace_put_vol);
117 * Look up or allocate a volume record.
119 static struct afs_volume *afs_lookup_volume(struct afs_fs_context *params,
120 struct afs_vldb_entry *vldb,
121 unsigned long type_mask)
123 struct afs_volume *candidate, *volume;
125 candidate = afs_alloc_volume(params, vldb, type_mask);
126 if (IS_ERR(candidate))
129 volume = afs_insert_volume_into_cell(params->cell, candidate);
130 if (volume != candidate)
131 afs_put_volume(params->net, candidate, afs_volume_trace_put_cell_dup);
136 * Look up a VLDB record for a volume.
138 static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell,
143 struct afs_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ);
144 struct afs_vl_cursor vc;
147 if (!afs_begin_vlserver_operation(&vc, cell, key))
148 return ERR_PTR(-ERESTARTSYS);
150 while (afs_select_vlserver(&vc)) {
151 vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz);
154 ret = afs_end_vlserver_operation(&vc);
155 return ret < 0 ? ERR_PTR(ret) : vldb;
159 * Look up a volume in the VL server and create a candidate volume record for
162 * The volume name can be one of the following:
163 * "%[cell:]volume[.]" R/W volume
164 * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
165 * or R/W (rwparent=1) volume
166 * "%[cell:]volume.readonly" R/O volume
167 * "#[cell:]volume.readonly" R/O volume
168 * "%[cell:]volume.backup" Backup volume
169 * "#[cell:]volume.backup" Backup volume
171 * The cell name is optional, and defaults to the current cell.
173 * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
175 * - Rule 1: Explicit type suffix forces access of that type or nothing
176 * (no suffix, then use Rule 2 & 3)
177 * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
179 * - Rule 3: If parent volume is R/W, then only mount R/W volume unless
180 * explicitly told otherwise
182 struct afs_volume *afs_create_volume(struct afs_fs_context *params)
184 struct afs_vldb_entry *vldb;
185 struct afs_volume *volume;
186 unsigned long type_mask = 1UL << params->type;
188 vldb = afs_vl_lookup_vldb(params->cell, params->key,
189 params->volname, params->volnamesz);
191 return ERR_CAST(vldb);
193 if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {
194 volume = ERR_PTR(vldb->error);
198 /* Make the final decision on the type we want */
199 volume = ERR_PTR(-ENOMEDIUM);
201 if (!(vldb->flags & type_mask))
203 } else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {
204 params->type = AFSVL_ROVOL;
205 } else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {
206 params->type = AFSVL_RWVOL;
211 type_mask = 1UL << params->type;
212 volume = afs_lookup_volume(params, vldb, type_mask);
220 * Destroy a volume record
222 static void afs_destroy_volume(struct afs_net *net, struct afs_volume *volume)
224 _enter("%p", volume);
226 #ifdef CONFIG_AFS_FSCACHE
227 ASSERTCMP(volume->cache, ==, NULL);
230 afs_remove_volume_from_cell(volume);
231 afs_put_serverlist(net, rcu_access_pointer(volume->servers));
232 afs_put_cell(volume->cell, afs_cell_trace_put_vol);
233 trace_afs_volume(volume->vid, refcount_read(&volume->ref),
234 afs_volume_trace_free);
235 kfree_rcu(volume, rcu);
237 _leave(" [destroyed]");
241 * Try to get a reference on a volume record.
243 bool afs_try_get_volume(struct afs_volume *volume, enum afs_volume_trace reason)
247 if (__refcount_inc_not_zero(&volume->ref, &r)) {
248 trace_afs_volume(volume->vid, r + 1, reason);
255 * Get a reference on a volume record.
257 struct afs_volume *afs_get_volume(struct afs_volume *volume,
258 enum afs_volume_trace reason)
263 __refcount_inc(&volume->ref, &r);
264 trace_afs_volume(volume->vid, r + 1, reason);
271 * Drop a reference on a volume record.
273 void afs_put_volume(struct afs_net *net, struct afs_volume *volume,
274 enum afs_volume_trace reason)
277 afs_volid_t vid = volume->vid;
281 zero = __refcount_dec_and_test(&volume->ref, &r);
282 trace_afs_volume(vid, r - 1, reason);
284 afs_destroy_volume(net, volume);
291 int afs_activate_volume(struct afs_volume *volume)
293 #ifdef CONFIG_AFS_FSCACHE
294 struct fscache_volume *vcookie;
297 name = kasprintf(GFP_KERNEL, "afs,%s,%llx",
298 volume->cell->name, volume->vid);
302 vcookie = fscache_acquire_volume(name, NULL, NULL, 0);
303 if (IS_ERR(vcookie)) {
304 if (vcookie != ERR_PTR(-EBUSY)) {
306 return PTR_ERR(vcookie);
308 pr_err("AFS: Cache volume key already in use (%s)\n", name);
311 volume->cache = vcookie;
318 * Deactivate a volume.
320 void afs_deactivate_volume(struct afs_volume *volume)
322 _enter("%s", volume->name);
324 #ifdef CONFIG_AFS_FSCACHE
325 fscache_relinquish_volume(volume->cache, NULL,
326 test_bit(AFS_VOLUME_DELETED, &volume->flags));
327 volume->cache = NULL;
334 * Query the VL service to update the volume status.
336 static int afs_update_volume_status(struct afs_volume *volume, struct key *key)
338 struct afs_server_list *new, *old, *discard;
339 struct afs_vldb_entry *vldb;
345 /* We look up an ID by passing it as a decimal string in the
346 * operation's name parameter.
348 idsz = sprintf(idbuf, "%llu", volume->vid);
350 vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);
356 /* See if the volume got renamed. */
357 if (vldb->name_len != volume->name_len ||
358 memcmp(vldb->name, volume->name, vldb->name_len) != 0) {
359 /* TODO: Use RCU'd string. */
360 memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);
361 volume->name_len = vldb->name_len;
364 /* See if the volume's server list got updated. */
365 new = afs_alloc_server_list(volume->cell, key,
366 vldb, (1 << volume->type));
372 write_lock(&volume->servers_lock);
375 old = rcu_dereference_protected(volume->servers,
376 lockdep_is_held(&volume->servers_lock));
377 if (afs_annotate_server_list(new, old)) {
378 new->seq = volume->servers_seq + 1;
379 rcu_assign_pointer(volume->servers, new);
381 volume->servers_seq++;
385 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
386 write_unlock(&volume->servers_lock);
389 afs_put_serverlist(volume->cell->net, discard);
393 _leave(" = %d", ret);
398 * Make sure the volume record is up to date.
400 int afs_check_volume_status(struct afs_volume *volume, struct afs_operation *op)
402 int ret, retries = 0;
407 if (test_bit(AFS_VOLUME_WAIT, &volume->flags))
409 if (volume->update_at <= ktime_get_real_seconds() ||
410 test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags))
416 if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
417 clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
418 ret = afs_update_volume_status(volume, op->key);
420 set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
421 clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);
422 clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);
423 wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);
424 _leave(" = %d", ret);
429 if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
430 _leave(" = 0 [no wait]");
434 ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT,
435 (op->flags & AFS_OPERATION_UNINTR) ?
436 TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
437 if (ret == -ERESTARTSYS) {
438 _leave(" = %d", ret);
444 _leave(" = -ESTALE");