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1// SPDX-License-Identifier: GPL-2.0-or-later2/* AFS volume management3 *4 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.5 * Written by David Howells (dhowells@redhat.com)6 */7 8#include <linux/kernel.h>9#include <linux/slab.h>10#include "internal.h"11 12static unsigned __read_mostly afs_volume_record_life = 60 * 60;13 14static void afs_destroy_volume(struct work_struct *work);15 16/*17 * Insert a volume into a cell. If there's an existing volume record, that is18 * returned instead with a ref held.19 */20static struct afs_volume *afs_insert_volume_into_cell(struct afs_cell *cell,21 struct afs_volume *volume)22{23 struct afs_volume *p;24 struct rb_node *parent = NULL, **pp;25 26 write_seqlock(&cell->volume_lock);27 28 pp = &cell->volumes.rb_node;29 while (*pp) {30 parent = *pp;31 p = rb_entry(parent, struct afs_volume, cell_node);32 if (p->vid < volume->vid) {33 pp = &(*pp)->rb_left;34 } else if (p->vid > volume->vid) {35 pp = &(*pp)->rb_right;36 } else {37 if (afs_try_get_volume(p, afs_volume_trace_get_cell_insert)) {38 volume = p;39 goto found;40 }41 42 set_bit(AFS_VOLUME_RM_TREE, &volume->flags);43 rb_replace_node_rcu(&p->cell_node, &volume->cell_node, &cell->volumes);44 }45 }46 47 rb_link_node_rcu(&volume->cell_node, parent, pp);48 rb_insert_color(&volume->cell_node, &cell->volumes);49 hlist_add_head_rcu(&volume->proc_link, &cell->proc_volumes);50 51found:52 write_sequnlock(&cell->volume_lock);53 return volume;54 55}56 57static void afs_remove_volume_from_cell(struct afs_volume *volume)58{59 struct afs_cell *cell = volume->cell;60 61 if (!hlist_unhashed(&volume->proc_link)) {62 trace_afs_volume(volume->vid, refcount_read(&cell->ref),63 afs_volume_trace_remove);64 write_seqlock(&cell->volume_lock);65 hlist_del_rcu(&volume->proc_link);66 if (!test_and_set_bit(AFS_VOLUME_RM_TREE, &volume->flags))67 rb_erase(&volume->cell_node, &cell->volumes);68 write_sequnlock(&cell->volume_lock);69 }70}71 72/*73 * Allocate a volume record and load it up from a vldb record.74 */75static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params,76 struct afs_vldb_entry *vldb,77 struct afs_server_list **_slist)78{79 struct afs_server_list *slist;80 struct afs_volume *volume;81 int ret = -ENOMEM, i;82 83 volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);84 if (!volume)85 goto error_0;86 87 volume->vid = vldb->vid[params->type];88 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;89 volume->cell = afs_get_cell(params->cell, afs_cell_trace_get_vol);90 volume->type = params->type;91 volume->type_force = params->force;92 volume->name_len = vldb->name_len;93 volume->creation_time = TIME64_MIN;94 volume->update_time = TIME64_MIN;95 96 refcount_set(&volume->ref, 1);97 INIT_HLIST_NODE(&volume->proc_link);98 INIT_WORK(&volume->destructor, afs_destroy_volume);99 rwlock_init(&volume->servers_lock);100 mutex_init(&volume->volsync_lock);101 mutex_init(&volume->cb_check_lock);102 rwlock_init(&volume->cb_v_break_lock);103 INIT_LIST_HEAD(&volume->open_mmaps);104 init_rwsem(&volume->open_mmaps_lock);105 memcpy(volume->name, vldb->name, vldb->name_len + 1);106 107 for (i = 0; i < AFS_MAXTYPES; i++)108 volume->vids[i] = vldb->vid[i];109 110 slist = afs_alloc_server_list(volume, params->key, vldb);111 if (IS_ERR(slist)) {112 ret = PTR_ERR(slist);113 goto error_1;114 }115 116 *_slist = slist;117 rcu_assign_pointer(volume->servers, slist);118 trace_afs_volume(volume->vid, 1, afs_volume_trace_alloc);119 return volume;120 121error_1:122 afs_put_cell(volume->cell, afs_cell_trace_put_vol);123 kfree(volume);124error_0:125 return ERR_PTR(ret);126}127 128/*129 * Look up or allocate a volume record.130 */131static struct afs_volume *afs_lookup_volume(struct afs_fs_context *params,132 struct afs_vldb_entry *vldb)133{134 struct afs_server_list *slist;135 struct afs_volume *candidate, *volume;136 137 candidate = afs_alloc_volume(params, vldb, &slist);138 if (IS_ERR(candidate))139 return candidate;140 141 volume = afs_insert_volume_into_cell(params->cell, candidate);142 if (volume == candidate)143 afs_attach_volume_to_servers(volume, slist);144 else145 afs_put_volume(candidate, afs_volume_trace_put_cell_dup);146 return volume;147}148 149/*150 * Look up a VLDB record for a volume.151 */152static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell,153 struct key *key,154 const char *volname,155 size_t volnamesz)156{157 struct afs_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ);158 struct afs_vl_cursor vc;159 int ret;160 161 if (!afs_begin_vlserver_operation(&vc, cell, key))162 return ERR_PTR(-ERESTARTSYS);163 164 while (afs_select_vlserver(&vc)) {165 vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz);166 }167 168 ret = afs_end_vlserver_operation(&vc);169 return ret < 0 ? ERR_PTR(ret) : vldb;170}171 172/*173 * Look up a volume in the VL server and create a candidate volume record for174 * it.175 *176 * The volume name can be one of the following:177 * "%[cell:]volume[.]" R/W volume178 * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),179 * or R/W (rwparent=1) volume180 * "%[cell:]volume.readonly" R/O volume181 * "#[cell:]volume.readonly" R/O volume182 * "%[cell:]volume.backup" Backup volume183 * "#[cell:]volume.backup" Backup volume184 *185 * The cell name is optional, and defaults to the current cell.186 *187 * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin188 * Guide189 * - Rule 1: Explicit type suffix forces access of that type or nothing190 * (no suffix, then use Rule 2 & 3)191 * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W192 * if not available193 * - Rule 3: If parent volume is R/W, then only mount R/W volume unless194 * explicitly told otherwise195 */196struct afs_volume *afs_create_volume(struct afs_fs_context *params)197{198 struct afs_vldb_entry *vldb;199 struct afs_volume *volume;200 unsigned long type_mask = 1UL << params->type;201 202 vldb = afs_vl_lookup_vldb(params->cell, params->key,203 params->volname, params->volnamesz);204 if (IS_ERR(vldb))205 return ERR_CAST(vldb);206 207 if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {208 volume = ERR_PTR(vldb->error);209 goto error;210 }211 212 /* Make the final decision on the type we want */213 volume = ERR_PTR(-ENOMEDIUM);214 if (params->force) {215 if (!(vldb->flags & type_mask))216 goto error;217 } else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {218 params->type = AFSVL_ROVOL;219 } else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {220 params->type = AFSVL_RWVOL;221 } else {222 goto error;223 }224 225 volume = afs_lookup_volume(params, vldb);226 227error:228 kfree(vldb);229 return volume;230}231 232/*233 * Destroy a volume record234 */235static void afs_destroy_volume(struct work_struct *work)236{237 struct afs_volume *volume = container_of(work, struct afs_volume, destructor);238 struct afs_server_list *slist = rcu_access_pointer(volume->servers);239 240 _enter("%p", volume);241 242#ifdef CONFIG_AFS_FSCACHE243 ASSERTCMP(volume->cache, ==, NULL);244#endif245 246 afs_detach_volume_from_servers(volume, slist);247 afs_remove_volume_from_cell(volume);248 afs_put_serverlist(volume->cell->net, slist);249 afs_put_cell(volume->cell, afs_cell_trace_put_vol);250 trace_afs_volume(volume->vid, refcount_read(&volume->ref),251 afs_volume_trace_free);252 kfree_rcu(volume, rcu);253 254 _leave(" [destroyed]");255}256 257/*258 * Try to get a reference on a volume record.259 */260bool afs_try_get_volume(struct afs_volume *volume, enum afs_volume_trace reason)261{262 int r;263 264 if (__refcount_inc_not_zero(&volume->ref, &r)) {265 trace_afs_volume(volume->vid, r + 1, reason);266 return true;267 }268 return false;269}270 271/*272 * Get a reference on a volume record.273 */274struct afs_volume *afs_get_volume(struct afs_volume *volume,275 enum afs_volume_trace reason)276{277 if (volume) {278 int r;279 280 __refcount_inc(&volume->ref, &r);281 trace_afs_volume(volume->vid, r + 1, reason);282 }283 return volume;284}285 286 287/*288 * Drop a reference on a volume record.289 */290void afs_put_volume(struct afs_volume *volume, enum afs_volume_trace reason)291{292 if (volume) {293 afs_volid_t vid = volume->vid;294 bool zero;295 int r;296 297 zero = __refcount_dec_and_test(&volume->ref, &r);298 trace_afs_volume(vid, r - 1, reason);299 if (zero)300 schedule_work(&volume->destructor);301 }302}303 304/*305 * Activate a volume.306 */307int afs_activate_volume(struct afs_volume *volume)308{309#ifdef CONFIG_AFS_FSCACHE310 struct fscache_volume *vcookie;311 char *name;312 313 name = kasprintf(GFP_KERNEL, "afs,%s,%llx",314 volume->cell->name, volume->vid);315 if (!name)316 return -ENOMEM;317 318 vcookie = fscache_acquire_volume(name, NULL, NULL, 0);319 if (IS_ERR(vcookie)) {320 if (vcookie != ERR_PTR(-EBUSY)) {321 kfree(name);322 return PTR_ERR(vcookie);323 }324 pr_err("AFS: Cache volume key already in use (%s)\n", name);325 vcookie = NULL;326 }327 volume->cache = vcookie;328 kfree(name);329#endif330 return 0;331}332 333/*334 * Deactivate a volume.335 */336void afs_deactivate_volume(struct afs_volume *volume)337{338 _enter("%s", volume->name);339 340#ifdef CONFIG_AFS_FSCACHE341 fscache_relinquish_volume(volume->cache, NULL,342 test_bit(AFS_VOLUME_DELETED, &volume->flags));343 volume->cache = NULL;344#endif345 346 _leave("");347}348 349/*350 * Query the VL service to update the volume status.351 */352static int afs_update_volume_status(struct afs_volume *volume, struct key *key)353{354 struct afs_server_list *new, *old, *discard;355 struct afs_vldb_entry *vldb;356 char idbuf[24];357 int ret, idsz;358 359 _enter("");360 361 /* We look up an ID by passing it as a decimal string in the362 * operation's name parameter.363 */364 idsz = snprintf(idbuf, sizeof(idbuf), "%llu", volume->vid);365 366 vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);367 if (IS_ERR(vldb)) {368 ret = PTR_ERR(vldb);369 goto error;370 }371 372 /* See if the volume got renamed. */373 if (vldb->name_len != volume->name_len ||374 memcmp(vldb->name, volume->name, vldb->name_len) != 0) {375 /* TODO: Use RCU'd string. */376 memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);377 volume->name_len = vldb->name_len;378 }379 380 /* See if the volume's server list got updated. */381 new = afs_alloc_server_list(volume, key, vldb);382 if (IS_ERR(new)) {383 ret = PTR_ERR(new);384 goto error_vldb;385 }386 387 write_lock(&volume->servers_lock);388 389 discard = new;390 old = rcu_dereference_protected(volume->servers,391 lockdep_is_held(&volume->servers_lock));392 if (afs_annotate_server_list(new, old)) {393 new->seq = volume->servers_seq + 1;394 rcu_assign_pointer(volume->servers, new);395 smp_wmb();396 volume->servers_seq++;397 discard = old;398 }399 400 /* Check more often if replication is ongoing. */401 if (new->ro_replicating)402 volume->update_at = ktime_get_real_seconds() + 10 * 60;403 else404 volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;405 write_unlock(&volume->servers_lock);406 407 if (discard == old)408 afs_reattach_volume_to_servers(volume, new, old);409 afs_put_serverlist(volume->cell->net, discard);410 ret = 0;411error_vldb:412 kfree(vldb);413error:414 _leave(" = %d", ret);415 return ret;416}417 418/*419 * Make sure the volume record is up to date.420 */421int afs_check_volume_status(struct afs_volume *volume, struct afs_operation *op)422{423 int ret, retries = 0;424 425 _enter("");426 427retry:428 if (test_bit(AFS_VOLUME_WAIT, &volume->flags))429 goto wait;430 if (volume->update_at <= ktime_get_real_seconds() ||431 test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags))432 goto update;433 _leave(" = 0");434 return 0;435 436update:437 if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {438 clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);439 ret = afs_update_volume_status(volume, op->key);440 if (ret < 0)441 set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);442 clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);443 clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);444 wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);445 _leave(" = %d", ret);446 return ret;447 }448 449wait:450 if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {451 _leave(" = 0 [no wait]");452 return 0;453 }454 455 ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT,456 (op->flags & AFS_OPERATION_UNINTR) ?457 TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);458 if (ret == -ERESTARTSYS) {459 _leave(" = %d", ret);460 return ret;461 }462 463 retries++;464 if (retries == 4) {465 _leave(" = -ESTALE");466 return -ESTALE;467 }468 goto retry;469}470