1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* AFS volume management 3 * 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 12 unsigned __read_mostly afs_volume_gc_delay = 10; 13 unsigned __read_mostly afs_volume_record_life = 60 * 60; 14 15 static const char *const afs_voltypes[] = { "R/W", "R/O", "BAK" }; 16 17 /* 18 * Allocate a volume record and load it up from a vldb record. 19 */ 20 static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params, 21 struct afs_vldb_entry *vldb, 22 unsigned long type_mask) 23 { 24 struct afs_server_list *slist; 25 struct afs_volume *volume; 26 int ret = -ENOMEM, nr_servers = 0, i; 27 28 for (i = 0; i < vldb->nr_servers; i++) 29 if (vldb->fs_mask[i] & type_mask) 30 nr_servers++; 31 32 volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL); 33 if (!volume) 34 goto error_0; 35 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; 42 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); 48 49 slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask); 50 if (IS_ERR(slist)) { 51 ret = PTR_ERR(slist); 52 goto error_1; 53 } 54 55 refcount_set(&slist->usage, 1); 56 volume->servers = slist; 57 return volume; 58 59 error_1: 60 afs_put_cell(params->net, volume->cell); 61 kfree(volume); 62 error_0: 63 return ERR_PTR(ret); 64 } 65 66 /* 67 * Look up a VLDB record for a volume. 68 */ 69 static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell, 70 struct key *key, 71 const char *volname, 72 size_t volnamesz) 73 { 74 struct afs_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ); 75 struct afs_vl_cursor vc; 76 int ret; 77 78 if (!afs_begin_vlserver_operation(&vc, cell, key)) 79 return ERR_PTR(-ERESTARTSYS); 80 81 while (afs_select_vlserver(&vc)) { 82 vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz); 83 } 84 85 ret = afs_end_vlserver_operation(&vc); 86 return ret < 0 ? ERR_PTR(ret) : vldb; 87 } 88 89 /* 90 * Look up a volume in the VL server and create a candidate volume record for 91 * it. 92 * 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 101 * 102 * The cell name is optional, and defaults to the current cell. 103 * 104 * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin 105 * Guide 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 109 * if not available 110 * - Rule 3: If parent volume is R/W, then only mount R/W volume unless 111 * explicitly told otherwise 112 */ 113 struct afs_volume *afs_create_volume(struct afs_fs_context *params) 114 { 115 struct afs_vldb_entry *vldb; 116 struct afs_volume *volume; 117 unsigned long type_mask = 1UL << params->type; 118 119 vldb = afs_vl_lookup_vldb(params->cell, params->key, 120 params->volname, params->volnamesz); 121 if (IS_ERR(vldb)) 122 return ERR_CAST(vldb); 123 124 if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) { 125 volume = ERR_PTR(vldb->error); 126 goto error; 127 } 128 129 /* Make the final decision on the type we want */ 130 volume = ERR_PTR(-ENOMEDIUM); 131 if (params->force) { 132 if (!(vldb->flags & type_mask)) 133 goto error; 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; 138 } else { 139 goto error; 140 } 141 142 type_mask = 1UL << params->type; 143 volume = afs_alloc_volume(params, vldb, type_mask); 144 145 error: 146 kfree(vldb); 147 return volume; 148 } 149 150 /* 151 * Destroy a volume record 152 */ 153 static void afs_destroy_volume(struct afs_net *net, struct afs_volume *volume) 154 { 155 _enter("%p", volume); 156 157 #ifdef CONFIG_AFS_FSCACHE 158 ASSERTCMP(volume->cache, ==, NULL); 159 #endif 160 161 afs_put_serverlist(net, volume->servers); 162 afs_put_cell(net, volume->cell); 163 kfree(volume); 164 165 _leave(" [destroyed]"); 166 } 167 168 /* 169 * Drop a reference on a volume record. 170 */ 171 void afs_put_volume(struct afs_cell *cell, struct afs_volume *volume) 172 { 173 if (volume) { 174 _enter("%s", volume->name); 175 176 if (atomic_dec_and_test(&volume->usage)) 177 afs_destroy_volume(cell->net, volume); 178 } 179 } 180 181 /* 182 * Activate a volume. 183 */ 184 void afs_activate_volume(struct afs_volume *volume) 185 { 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), 190 NULL, 0, 191 volume, 0, true); 192 #endif 193 194 write_lock(&volume->cell->proc_lock); 195 list_add_tail(&volume->proc_link, &volume->cell->proc_volumes); 196 write_unlock(&volume->cell->proc_lock); 197 } 198 199 /* 200 * Deactivate a volume. 201 */ 202 void afs_deactivate_volume(struct afs_volume *volume) 203 { 204 _enter("%s", volume->name); 205 206 write_lock(&volume->cell->proc_lock); 207 list_del_init(&volume->proc_link); 208 write_unlock(&volume->cell->proc_lock); 209 210 #ifdef CONFIG_AFS_FSCACHE 211 fscache_relinquish_cookie(volume->cache, NULL, 212 test_bit(AFS_VOLUME_DELETED, &volume->flags)); 213 volume->cache = NULL; 214 #endif 215 216 _leave(""); 217 } 218 219 /* 220 * Query the VL service to update the volume status. 221 */ 222 static int afs_update_volume_status(struct afs_volume *volume, struct key *key) 223 { 224 struct afs_server_list *new, *old, *discard; 225 struct afs_vldb_entry *vldb; 226 char idbuf[16]; 227 int ret, idsz; 228 229 _enter(""); 230 231 /* We look up an ID by passing it as a decimal string in the 232 * operation's name parameter. 233 */ 234 idsz = sprintf(idbuf, "%llu", volume->vid); 235 236 vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz); 237 if (IS_ERR(vldb)) { 238 ret = PTR_ERR(vldb); 239 goto error; 240 } 241 242 /* 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; 248 } 249 250 /* See if the volume's server list got updated. */ 251 new = afs_alloc_server_list(volume->cell, key, 252 vldb, (1 << volume->type)); 253 if (IS_ERR(new)) { 254 ret = PTR_ERR(new); 255 goto error_vldb; 256 } 257 258 write_lock(&volume->servers_lock); 259 260 discard = new; 261 old = volume->servers; 262 if (afs_annotate_server_list(new, old)) { 263 new->seq = volume->servers_seq + 1; 264 volume->servers = new; 265 smp_wmb(); 266 volume->servers_seq++; 267 discard = old; 268 } 269 270 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); 273 ret = 0; 274 275 afs_put_serverlist(volume->cell->net, discard); 276 error_vldb: 277 kfree(vldb); 278 error: 279 _leave(" = %d", ret); 280 return ret; 281 } 282 283 /* 284 * Make sure the volume record is up to date. 285 */ 286 int afs_check_volume_status(struct afs_volume *volume, struct key *key) 287 { 288 time64_t now = ktime_get_real_seconds(); 289 int ret, retries = 0; 290 291 _enter(""); 292 293 if (volume->update_at <= now) 294 set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags); 295 296 retry: 297 if (!test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags) && 298 !test_bit(AFS_VOLUME_WAIT, &volume->flags)) { 299 _leave(" = 0"); 300 return 0; 301 } 302 303 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); 309 return ret; 310 } 311 312 if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) { 313 _leave(" = 0 [no wait]"); 314 return 0; 315 } 316 317 ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT, TASK_INTERRUPTIBLE); 318 if (ret == -ERESTARTSYS) { 319 _leave(" = %d", ret); 320 return ret; 321 } 322 323 retries++; 324 if (retries == 4) { 325 _leave(" = -ESTALE"); 326 return -ESTALE; 327 } 328 goto retry; 329 } 330