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