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ec26815a | 1 | /* AFS volume management |
1da177e4 LT |
2 | * |
3 | * Copyright (C) 2002 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/module.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/fs.h> | |
17 | #include <linux/pagemap.h> | |
18 | #include "volume.h" | |
19 | #include "vnode.h" | |
20 | #include "cell.h" | |
21 | #include "cache.h" | |
22 | #include "cmservice.h" | |
23 | #include "fsclient.h" | |
24 | #include "vlclient.h" | |
25 | #include "internal.h" | |
26 | ||
27 | #ifdef __KDEBUG | |
28 | static const char *afs_voltypes[] = { "R/W", "R/O", "BAK" }; | |
29 | #endif | |
30 | ||
31 | #ifdef AFS_CACHING_SUPPORT | |
32 | static cachefs_match_val_t afs_volume_cache_match(void *target, | |
33 | const void *entry); | |
34 | static void afs_volume_cache_update(void *source, void *entry); | |
35 | ||
36 | struct cachefs_index_def afs_volume_cache_index_def = { | |
37 | .name = "volume", | |
38 | .data_size = sizeof(struct afs_cache_vhash), | |
39 | .keys[0] = { CACHEFS_INDEX_KEYS_BIN, 1 }, | |
40 | .keys[1] = { CACHEFS_INDEX_KEYS_BIN, 1 }, | |
41 | .match = afs_volume_cache_match, | |
42 | .update = afs_volume_cache_update, | |
43 | }; | |
44 | #endif | |
45 | ||
1da177e4 LT |
46 | /* |
47 | * lookup a volume by name | |
48 | * - this can be one of the following: | |
49 | * "%[cell:]volume[.]" R/W volume | |
50 | * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0), | |
51 | * or R/W (rwparent=1) volume | |
52 | * "%[cell:]volume.readonly" R/O volume | |
53 | * "#[cell:]volume.readonly" R/O volume | |
54 | * "%[cell:]volume.backup" Backup volume | |
55 | * "#[cell:]volume.backup" Backup volume | |
56 | * | |
57 | * The cell name is optional, and defaults to the current cell. | |
58 | * | |
59 | * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin | |
60 | * Guide | |
61 | * - Rule 1: Explicit type suffix forces access of that type or nothing | |
62 | * (no suffix, then use Rule 2 & 3) | |
63 | * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W | |
64 | * if not available | |
65 | * - Rule 3: If parent volume is R/W, then only mount R/W volume unless | |
66 | * explicitly told otherwise | |
67 | */ | |
68 | int afs_volume_lookup(const char *name, struct afs_cell *cell, int rwpath, | |
69 | struct afs_volume **_volume) | |
70 | { | |
71 | struct afs_vlocation *vlocation = NULL; | |
72 | struct afs_volume *volume = NULL; | |
73 | afs_voltype_t type; | |
74 | const char *cellname, *volname, *suffix; | |
75 | char srvtmask; | |
76 | int force, ret, loop, cellnamesz, volnamesz; | |
77 | ||
78 | _enter("%s,,%d,", name, rwpath); | |
79 | ||
80 | if (!name || (name[0] != '%' && name[0] != '#') || !name[1]) { | |
81 | printk("kAFS: unparsable volume name\n"); | |
82 | return -EINVAL; | |
83 | } | |
84 | ||
85 | /* determine the type of volume we're looking for */ | |
86 | force = 0; | |
87 | type = AFSVL_ROVOL; | |
88 | ||
89 | if (rwpath || name[0] == '%') { | |
90 | type = AFSVL_RWVOL; | |
91 | force = 1; | |
92 | } | |
93 | ||
94 | suffix = strrchr(name, '.'); | |
95 | if (suffix) { | |
96 | if (strcmp(suffix, ".readonly") == 0) { | |
97 | type = AFSVL_ROVOL; | |
98 | force = 1; | |
ec26815a | 99 | } else if (strcmp(suffix, ".backup") == 0) { |
1da177e4 LT |
100 | type = AFSVL_BACKVOL; |
101 | force = 1; | |
ec26815a DH |
102 | } else if (suffix[1] == 0) { |
103 | } else { | |
1da177e4 LT |
104 | suffix = NULL; |
105 | } | |
106 | } | |
107 | ||
108 | /* split the cell and volume names */ | |
109 | name++; | |
110 | volname = strchr(name, ':'); | |
111 | if (volname) { | |
112 | cellname = name; | |
113 | cellnamesz = volname - name; | |
114 | volname++; | |
ec26815a | 115 | } else { |
1da177e4 LT |
116 | volname = name; |
117 | cellname = NULL; | |
118 | cellnamesz = 0; | |
119 | } | |
120 | ||
121 | volnamesz = suffix ? suffix - volname : strlen(volname); | |
122 | ||
123 | _debug("CELL:%*.*s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s", | |
124 | cellnamesz, cellnamesz, cellname ?: "", cell, | |
125 | volnamesz, volnamesz, volname, suffix ?: "-", | |
126 | type, | |
127 | force ? " FORCE" : ""); | |
128 | ||
129 | /* lookup the cell record */ | |
130 | if (cellname || !cell) { | |
131 | ret = afs_cell_lookup(cellname, cellnamesz, &cell); | |
132 | if (ret<0) { | |
133 | printk("kAFS: unable to lookup cell '%s'\n", | |
134 | cellname ?: ""); | |
135 | goto error; | |
136 | } | |
ec26815a | 137 | } else { |
1da177e4 LT |
138 | afs_get_cell(cell); |
139 | } | |
140 | ||
141 | /* lookup the volume location record */ | |
142 | ret = afs_vlocation_lookup(cell, volname, volnamesz, &vlocation); | |
143 | if (ret < 0) | |
144 | goto error; | |
145 | ||
146 | /* make the final decision on the type we want */ | |
147 | ret = -ENOMEDIUM; | |
148 | if (force && !(vlocation->vldb.vidmask & (1 << type))) | |
149 | goto error; | |
150 | ||
151 | srvtmask = 0; | |
152 | for (loop = 0; loop < vlocation->vldb.nservers; loop++) | |
153 | srvtmask |= vlocation->vldb.srvtmask[loop]; | |
154 | ||
155 | if (force) { | |
156 | if (!(srvtmask & (1 << type))) | |
157 | goto error; | |
ec26815a | 158 | } else if (srvtmask & AFS_VOL_VTM_RO) { |
1da177e4 | 159 | type = AFSVL_ROVOL; |
ec26815a | 160 | } else if (srvtmask & AFS_VOL_VTM_RW) { |
1da177e4 | 161 | type = AFSVL_RWVOL; |
ec26815a | 162 | } else { |
1da177e4 LT |
163 | goto error; |
164 | } | |
165 | ||
166 | down_write(&cell->vl_sem); | |
167 | ||
168 | /* is the volume already active? */ | |
169 | if (vlocation->vols[type]) { | |
170 | /* yes - re-use it */ | |
171 | volume = vlocation->vols[type]; | |
172 | afs_get_volume(volume); | |
173 | goto success; | |
174 | } | |
175 | ||
176 | /* create a new volume record */ | |
177 | _debug("creating new volume record"); | |
178 | ||
179 | ret = -ENOMEM; | |
f8314dc6 | 180 | volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL); |
1da177e4 LT |
181 | if (!volume) |
182 | goto error_up; | |
183 | ||
1da177e4 LT |
184 | atomic_set(&volume->usage, 1); |
185 | volume->type = type; | |
186 | volume->type_force = force; | |
187 | volume->cell = cell; | |
188 | volume->vid = vlocation->vldb.vid[type]; | |
189 | ||
190 | init_rwsem(&volume->server_sem); | |
191 | ||
192 | /* look up all the applicable server records */ | |
193 | for (loop = 0; loop < 8; loop++) { | |
194 | if (vlocation->vldb.srvtmask[loop] & (1 << volume->type)) { | |
195 | ret = afs_server_lookup( | |
196 | volume->cell, | |
197 | &vlocation->vldb.servers[loop], | |
198 | &volume->servers[volume->nservers]); | |
199 | if (ret < 0) | |
200 | goto error_discard; | |
201 | ||
202 | volume->nservers++; | |
203 | } | |
204 | } | |
205 | ||
206 | /* attach the cache and volume location */ | |
207 | #ifdef AFS_CACHING_SUPPORT | |
208 | cachefs_acquire_cookie(vlocation->cache, | |
209 | &afs_vnode_cache_index_def, | |
210 | volume, | |
211 | &volume->cache); | |
212 | #endif | |
213 | ||
214 | afs_get_vlocation(vlocation); | |
215 | volume->vlocation = vlocation; | |
216 | ||
217 | vlocation->vols[type] = volume; | |
218 | ||
ec26815a | 219 | success: |
1da177e4 LT |
220 | _debug("kAFS selected %s volume %08x", |
221 | afs_voltypes[volume->type], volume->vid); | |
222 | *_volume = volume; | |
223 | ret = 0; | |
224 | ||
225 | /* clean up */ | |
ec26815a | 226 | error_up: |
1da177e4 | 227 | up_write(&cell->vl_sem); |
ec26815a | 228 | error: |
1da177e4 LT |
229 | afs_put_vlocation(vlocation); |
230 | afs_put_cell(cell); | |
231 | ||
232 | _leave(" = %d (%p)", ret, volume); | |
233 | return ret; | |
234 | ||
ec26815a | 235 | error_discard: |
1da177e4 LT |
236 | up_write(&cell->vl_sem); |
237 | ||
238 | for (loop = volume->nservers - 1; loop >= 0; loop--) | |
239 | afs_put_server(volume->servers[loop]); | |
240 | ||
241 | kfree(volume); | |
242 | goto error; | |
ec26815a | 243 | } |
1da177e4 | 244 | |
1da177e4 LT |
245 | /* |
246 | * destroy a volume record | |
247 | */ | |
248 | void afs_put_volume(struct afs_volume *volume) | |
249 | { | |
250 | struct afs_vlocation *vlocation; | |
251 | int loop; | |
252 | ||
253 | if (!volume) | |
254 | return; | |
255 | ||
256 | _enter("%p", volume); | |
257 | ||
258 | vlocation = volume->vlocation; | |
259 | ||
260 | /* sanity check */ | |
261 | BUG_ON(atomic_read(&volume->usage) <= 0); | |
262 | ||
263 | /* to prevent a race, the decrement and the dequeue must be effectively | |
264 | * atomic */ | |
265 | down_write(&vlocation->cell->vl_sem); | |
266 | ||
267 | if (likely(!atomic_dec_and_test(&volume->usage))) { | |
268 | up_write(&vlocation->cell->vl_sem); | |
269 | _leave(""); | |
270 | return; | |
271 | } | |
272 | ||
273 | vlocation->vols[volume->type] = NULL; | |
274 | ||
275 | up_write(&vlocation->cell->vl_sem); | |
276 | ||
277 | /* finish cleaning up the volume */ | |
278 | #ifdef AFS_CACHING_SUPPORT | |
279 | cachefs_relinquish_cookie(volume->cache, 0); | |
280 | #endif | |
281 | afs_put_vlocation(vlocation); | |
282 | ||
283 | for (loop = volume->nservers - 1; loop >= 0; loop--) | |
284 | afs_put_server(volume->servers[loop]); | |
285 | ||
286 | kfree(volume); | |
287 | ||
288 | _leave(" [destroyed]"); | |
ec26815a | 289 | } |
1da177e4 | 290 | |
1da177e4 LT |
291 | /* |
292 | * pick a server to use to try accessing this volume | |
293 | * - returns with an elevated usage count on the server chosen | |
294 | */ | |
295 | int afs_volume_pick_fileserver(struct afs_volume *volume, | |
296 | struct afs_server **_server) | |
297 | { | |
298 | struct afs_server *server; | |
299 | int ret, state, loop; | |
300 | ||
301 | _enter("%s", volume->vlocation->vldb.name); | |
302 | ||
303 | down_read(&volume->server_sem); | |
304 | ||
305 | /* handle the no-server case */ | |
306 | if (volume->nservers == 0) { | |
307 | ret = volume->rjservers ? -ENOMEDIUM : -ESTALE; | |
308 | up_read(&volume->server_sem); | |
309 | _leave(" = %d [no servers]", ret); | |
310 | return ret; | |
311 | } | |
312 | ||
313 | /* basically, just search the list for the first live server and use | |
314 | * that */ | |
315 | ret = 0; | |
316 | for (loop = 0; loop < volume->nservers; loop++) { | |
317 | server = volume->servers[loop]; | |
318 | state = server->fs_state; | |
319 | ||
320 | switch (state) { | |
321 | /* found an apparently healthy server */ | |
322 | case 0: | |
323 | afs_get_server(server); | |
324 | up_read(&volume->server_sem); | |
325 | *_server = server; | |
326 | _leave(" = 0 (picked %08x)", | |
327 | ntohl(server->addr.s_addr)); | |
328 | return 0; | |
329 | ||
330 | case -ENETUNREACH: | |
331 | if (ret == 0) | |
332 | ret = state; | |
333 | break; | |
334 | ||
335 | case -EHOSTUNREACH: | |
336 | if (ret == 0 || | |
337 | ret == -ENETUNREACH) | |
338 | ret = state; | |
339 | break; | |
340 | ||
341 | case -ECONNREFUSED: | |
342 | if (ret == 0 || | |
343 | ret == -ENETUNREACH || | |
344 | ret == -EHOSTUNREACH) | |
345 | ret = state; | |
346 | break; | |
347 | ||
348 | default: | |
349 | case -EREMOTEIO: | |
350 | if (ret == 0 || | |
351 | ret == -ENETUNREACH || | |
352 | ret == -EHOSTUNREACH || | |
353 | ret == -ECONNREFUSED) | |
354 | ret = state; | |
355 | break; | |
356 | } | |
357 | } | |
358 | ||
359 | /* no available servers | |
360 | * - TODO: handle the no active servers case better | |
361 | */ | |
362 | up_read(&volume->server_sem); | |
363 | _leave(" = %d", ret); | |
364 | return ret; | |
ec26815a | 365 | } |
1da177e4 | 366 | |
1da177e4 LT |
367 | /* |
368 | * release a server after use | |
369 | * - releases the ref on the server struct that was acquired by picking | |
370 | * - records result of using a particular server to access a volume | |
371 | * - return 0 to try again, 1 if okay or to issue error | |
372 | */ | |
373 | int afs_volume_release_fileserver(struct afs_volume *volume, | |
374 | struct afs_server *server, | |
375 | int result) | |
376 | { | |
377 | unsigned loop; | |
378 | ||
379 | _enter("%s,%08x,%d", | |
380 | volume->vlocation->vldb.name, ntohl(server->addr.s_addr), | |
381 | result); | |
382 | ||
383 | switch (result) { | |
384 | /* success */ | |
385 | case 0: | |
386 | server->fs_act_jif = jiffies; | |
387 | break; | |
388 | ||
389 | /* the fileserver denied all knowledge of the volume */ | |
390 | case -ENOMEDIUM: | |
391 | server->fs_act_jif = jiffies; | |
392 | down_write(&volume->server_sem); | |
393 | ||
394 | /* first, find where the server is in the active list (if it | |
395 | * is) */ | |
396 | for (loop = 0; loop < volume->nservers; loop++) | |
397 | if (volume->servers[loop] == server) | |
398 | goto present; | |
399 | ||
400 | /* no longer there - may have been discarded by another op */ | |
401 | goto try_next_server_upw; | |
402 | ||
403 | present: | |
404 | volume->nservers--; | |
405 | memmove(&volume->servers[loop], | |
406 | &volume->servers[loop + 1], | |
407 | sizeof(volume->servers[loop]) * | |
408 | (volume->nservers - loop)); | |
409 | volume->servers[volume->nservers] = NULL; | |
410 | afs_put_server(server); | |
411 | volume->rjservers++; | |
412 | ||
413 | if (volume->nservers > 0) | |
414 | /* another server might acknowledge its existence */ | |
415 | goto try_next_server_upw; | |
416 | ||
417 | /* handle the case where all the fileservers have rejected the | |
418 | * volume | |
419 | * - TODO: try asking the fileservers for volume information | |
420 | * - TODO: contact the VL server again to see if the volume is | |
421 | * no longer registered | |
422 | */ | |
423 | up_write(&volume->server_sem); | |
424 | afs_put_server(server); | |
425 | _leave(" [completely rejected]"); | |
426 | return 1; | |
427 | ||
428 | /* problem reaching the server */ | |
429 | case -ENETUNREACH: | |
430 | case -EHOSTUNREACH: | |
431 | case -ECONNREFUSED: | |
432 | case -ETIMEDOUT: | |
433 | case -EREMOTEIO: | |
434 | /* mark the server as dead | |
435 | * TODO: vary dead timeout depending on error | |
436 | */ | |
437 | spin_lock(&server->fs_lock); | |
438 | if (!server->fs_state) { | |
439 | server->fs_dead_jif = jiffies + HZ * 10; | |
440 | server->fs_state = result; | |
441 | printk("kAFS: SERVER DEAD state=%d\n", result); | |
442 | } | |
443 | spin_unlock(&server->fs_lock); | |
444 | goto try_next_server; | |
445 | ||
446 | /* miscellaneous error */ | |
447 | default: | |
448 | server->fs_act_jif = jiffies; | |
449 | case -ENOMEM: | |
450 | case -ENONET: | |
451 | break; | |
452 | } | |
453 | ||
454 | /* tell the caller to accept the result */ | |
455 | afs_put_server(server); | |
456 | _leave(""); | |
457 | return 1; | |
458 | ||
459 | /* tell the caller to loop around and try the next server */ | |
ec26815a | 460 | try_next_server_upw: |
1da177e4 | 461 | up_write(&volume->server_sem); |
ec26815a | 462 | try_next_server: |
1da177e4 LT |
463 | afs_put_server(server); |
464 | _leave(" [try next server]"); | |
465 | return 0; | |
ec26815a | 466 | } |
1da177e4 | 467 | |
1da177e4 LT |
468 | /* |
469 | * match a volume hash record stored in the cache | |
470 | */ | |
471 | #ifdef AFS_CACHING_SUPPORT | |
472 | static cachefs_match_val_t afs_volume_cache_match(void *target, | |
473 | const void *entry) | |
474 | { | |
475 | const struct afs_cache_vhash *vhash = entry; | |
476 | struct afs_volume *volume = target; | |
477 | ||
478 | _enter("{%u},{%u}", volume->type, vhash->vtype); | |
479 | ||
480 | if (volume->type == vhash->vtype) { | |
481 | _leave(" = SUCCESS"); | |
482 | return CACHEFS_MATCH_SUCCESS; | |
483 | } | |
484 | ||
485 | _leave(" = FAILED"); | |
486 | return CACHEFS_MATCH_FAILED; | |
ec26815a | 487 | } |
1da177e4 LT |
488 | #endif |
489 | ||
1da177e4 LT |
490 | /* |
491 | * update a volume hash record stored in the cache | |
492 | */ | |
493 | #ifdef AFS_CACHING_SUPPORT | |
494 | static void afs_volume_cache_update(void *source, void *entry) | |
495 | { | |
496 | struct afs_cache_vhash *vhash = entry; | |
497 | struct afs_volume *volume = source; | |
498 | ||
499 | _enter(""); | |
500 | ||
501 | vhash->vtype = volume->type; | |
ec26815a | 502 | } |
1da177e4 | 503 | #endif |