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1 | /* volume.c: AFS volume management |
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 | ||
46 | /*****************************************************************************/ | |
47 | /* | |
48 | * lookup a volume by name | |
49 | * - this can be one of the following: | |
50 | * "%[cell:]volume[.]" R/W volume | |
51 | * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0), | |
52 | * or R/W (rwparent=1) volume | |
53 | * "%[cell:]volume.readonly" R/O volume | |
54 | * "#[cell:]volume.readonly" R/O volume | |
55 | * "%[cell:]volume.backup" Backup volume | |
56 | * "#[cell:]volume.backup" Backup volume | |
57 | * | |
58 | * The cell name is optional, and defaults to the current cell. | |
59 | * | |
60 | * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin | |
61 | * Guide | |
62 | * - Rule 1: Explicit type suffix forces access of that type or nothing | |
63 | * (no suffix, then use Rule 2 & 3) | |
64 | * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W | |
65 | * if not available | |
66 | * - Rule 3: If parent volume is R/W, then only mount R/W volume unless | |
67 | * explicitly told otherwise | |
68 | */ | |
69 | int afs_volume_lookup(const char *name, struct afs_cell *cell, int rwpath, | |
70 | struct afs_volume **_volume) | |
71 | { | |
72 | struct afs_vlocation *vlocation = NULL; | |
73 | struct afs_volume *volume = NULL; | |
74 | afs_voltype_t type; | |
75 | const char *cellname, *volname, *suffix; | |
76 | char srvtmask; | |
77 | int force, ret, loop, cellnamesz, volnamesz; | |
78 | ||
79 | _enter("%s,,%d,", name, rwpath); | |
80 | ||
81 | if (!name || (name[0] != '%' && name[0] != '#') || !name[1]) { | |
82 | printk("kAFS: unparsable volume name\n"); | |
83 | return -EINVAL; | |
84 | } | |
85 | ||
86 | /* determine the type of volume we're looking for */ | |
87 | force = 0; | |
88 | type = AFSVL_ROVOL; | |
89 | ||
90 | if (rwpath || name[0] == '%') { | |
91 | type = AFSVL_RWVOL; | |
92 | force = 1; | |
93 | } | |
94 | ||
95 | suffix = strrchr(name, '.'); | |
96 | if (suffix) { | |
97 | if (strcmp(suffix, ".readonly") == 0) { | |
98 | type = AFSVL_ROVOL; | |
99 | force = 1; | |
100 | } | |
101 | else if (strcmp(suffix, ".backup") == 0) { | |
102 | type = AFSVL_BACKVOL; | |
103 | force = 1; | |
104 | } | |
105 | else if (suffix[1] == 0) { | |
106 | } | |
107 | else { | |
108 | suffix = NULL; | |
109 | } | |
110 | } | |
111 | ||
112 | /* split the cell and volume names */ | |
113 | name++; | |
114 | volname = strchr(name, ':'); | |
115 | if (volname) { | |
116 | cellname = name; | |
117 | cellnamesz = volname - name; | |
118 | volname++; | |
119 | } | |
120 | else { | |
121 | volname = name; | |
122 | cellname = NULL; | |
123 | cellnamesz = 0; | |
124 | } | |
125 | ||
126 | volnamesz = suffix ? suffix - volname : strlen(volname); | |
127 | ||
128 | _debug("CELL:%*.*s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s", | |
129 | cellnamesz, cellnamesz, cellname ?: "", cell, | |
130 | volnamesz, volnamesz, volname, suffix ?: "-", | |
131 | type, | |
132 | force ? " FORCE" : ""); | |
133 | ||
134 | /* lookup the cell record */ | |
135 | if (cellname || !cell) { | |
136 | ret = afs_cell_lookup(cellname, cellnamesz, &cell); | |
137 | if (ret<0) { | |
138 | printk("kAFS: unable to lookup cell '%s'\n", | |
139 | cellname ?: ""); | |
140 | goto error; | |
141 | } | |
142 | } | |
143 | else { | |
144 | afs_get_cell(cell); | |
145 | } | |
146 | ||
147 | /* lookup the volume location record */ | |
148 | ret = afs_vlocation_lookup(cell, volname, volnamesz, &vlocation); | |
149 | if (ret < 0) | |
150 | goto error; | |
151 | ||
152 | /* make the final decision on the type we want */ | |
153 | ret = -ENOMEDIUM; | |
154 | if (force && !(vlocation->vldb.vidmask & (1 << type))) | |
155 | goto error; | |
156 | ||
157 | srvtmask = 0; | |
158 | for (loop = 0; loop < vlocation->vldb.nservers; loop++) | |
159 | srvtmask |= vlocation->vldb.srvtmask[loop]; | |
160 | ||
161 | if (force) { | |
162 | if (!(srvtmask & (1 << type))) | |
163 | goto error; | |
164 | } | |
165 | else if (srvtmask & AFS_VOL_VTM_RO) { | |
166 | type = AFSVL_ROVOL; | |
167 | } | |
168 | else if (srvtmask & AFS_VOL_VTM_RW) { | |
169 | type = AFSVL_RWVOL; | |
170 | } | |
171 | else { | |
172 | goto error; | |
173 | } | |
174 | ||
175 | down_write(&cell->vl_sem); | |
176 | ||
177 | /* is the volume already active? */ | |
178 | if (vlocation->vols[type]) { | |
179 | /* yes - re-use it */ | |
180 | volume = vlocation->vols[type]; | |
181 | afs_get_volume(volume); | |
182 | goto success; | |
183 | } | |
184 | ||
185 | /* create a new volume record */ | |
186 | _debug("creating new volume record"); | |
187 | ||
188 | ret = -ENOMEM; | |
189 | volume = kmalloc(sizeof(struct afs_volume), GFP_KERNEL); | |
190 | if (!volume) | |
191 | goto error_up; | |
192 | ||
193 | memset(volume, 0, sizeof(struct afs_volume)); | |
194 | atomic_set(&volume->usage, 1); | |
195 | volume->type = type; | |
196 | volume->type_force = force; | |
197 | volume->cell = cell; | |
198 | volume->vid = vlocation->vldb.vid[type]; | |
199 | ||
200 | init_rwsem(&volume->server_sem); | |
201 | ||
202 | /* look up all the applicable server records */ | |
203 | for (loop = 0; loop < 8; loop++) { | |
204 | if (vlocation->vldb.srvtmask[loop] & (1 << volume->type)) { | |
205 | ret = afs_server_lookup( | |
206 | volume->cell, | |
207 | &vlocation->vldb.servers[loop], | |
208 | &volume->servers[volume->nservers]); | |
209 | if (ret < 0) | |
210 | goto error_discard; | |
211 | ||
212 | volume->nservers++; | |
213 | } | |
214 | } | |
215 | ||
216 | /* attach the cache and volume location */ | |
217 | #ifdef AFS_CACHING_SUPPORT | |
218 | cachefs_acquire_cookie(vlocation->cache, | |
219 | &afs_vnode_cache_index_def, | |
220 | volume, | |
221 | &volume->cache); | |
222 | #endif | |
223 | ||
224 | afs_get_vlocation(vlocation); | |
225 | volume->vlocation = vlocation; | |
226 | ||
227 | vlocation->vols[type] = volume; | |
228 | ||
229 | success: | |
230 | _debug("kAFS selected %s volume %08x", | |
231 | afs_voltypes[volume->type], volume->vid); | |
232 | *_volume = volume; | |
233 | ret = 0; | |
234 | ||
235 | /* clean up */ | |
236 | error_up: | |
237 | up_write(&cell->vl_sem); | |
238 | error: | |
239 | afs_put_vlocation(vlocation); | |
240 | afs_put_cell(cell); | |
241 | ||
242 | _leave(" = %d (%p)", ret, volume); | |
243 | return ret; | |
244 | ||
245 | error_discard: | |
246 | up_write(&cell->vl_sem); | |
247 | ||
248 | for (loop = volume->nservers - 1; loop >= 0; loop--) | |
249 | afs_put_server(volume->servers[loop]); | |
250 | ||
251 | kfree(volume); | |
252 | goto error; | |
253 | } /* end afs_volume_lookup() */ | |
254 | ||
255 | /*****************************************************************************/ | |
256 | /* | |
257 | * destroy a volume record | |
258 | */ | |
259 | void afs_put_volume(struct afs_volume *volume) | |
260 | { | |
261 | struct afs_vlocation *vlocation; | |
262 | int loop; | |
263 | ||
264 | if (!volume) | |
265 | return; | |
266 | ||
267 | _enter("%p", volume); | |
268 | ||
269 | vlocation = volume->vlocation; | |
270 | ||
271 | /* sanity check */ | |
272 | BUG_ON(atomic_read(&volume->usage) <= 0); | |
273 | ||
274 | /* to prevent a race, the decrement and the dequeue must be effectively | |
275 | * atomic */ | |
276 | down_write(&vlocation->cell->vl_sem); | |
277 | ||
278 | if (likely(!atomic_dec_and_test(&volume->usage))) { | |
279 | up_write(&vlocation->cell->vl_sem); | |
280 | _leave(""); | |
281 | return; | |
282 | } | |
283 | ||
284 | vlocation->vols[volume->type] = NULL; | |
285 | ||
286 | up_write(&vlocation->cell->vl_sem); | |
287 | ||
288 | /* finish cleaning up the volume */ | |
289 | #ifdef AFS_CACHING_SUPPORT | |
290 | cachefs_relinquish_cookie(volume->cache, 0); | |
291 | #endif | |
292 | afs_put_vlocation(vlocation); | |
293 | ||
294 | for (loop = volume->nservers - 1; loop >= 0; loop--) | |
295 | afs_put_server(volume->servers[loop]); | |
296 | ||
297 | kfree(volume); | |
298 | ||
299 | _leave(" [destroyed]"); | |
300 | } /* end afs_put_volume() */ | |
301 | ||
302 | /*****************************************************************************/ | |
303 | /* | |
304 | * pick a server to use to try accessing this volume | |
305 | * - returns with an elevated usage count on the server chosen | |
306 | */ | |
307 | int afs_volume_pick_fileserver(struct afs_volume *volume, | |
308 | struct afs_server **_server) | |
309 | { | |
310 | struct afs_server *server; | |
311 | int ret, state, loop; | |
312 | ||
313 | _enter("%s", volume->vlocation->vldb.name); | |
314 | ||
315 | down_read(&volume->server_sem); | |
316 | ||
317 | /* handle the no-server case */ | |
318 | if (volume->nservers == 0) { | |
319 | ret = volume->rjservers ? -ENOMEDIUM : -ESTALE; | |
320 | up_read(&volume->server_sem); | |
321 | _leave(" = %d [no servers]", ret); | |
322 | return ret; | |
323 | } | |
324 | ||
325 | /* basically, just search the list for the first live server and use | |
326 | * that */ | |
327 | ret = 0; | |
328 | for (loop = 0; loop < volume->nservers; loop++) { | |
329 | server = volume->servers[loop]; | |
330 | state = server->fs_state; | |
331 | ||
332 | switch (state) { | |
333 | /* found an apparently healthy server */ | |
334 | case 0: | |
335 | afs_get_server(server); | |
336 | up_read(&volume->server_sem); | |
337 | *_server = server; | |
338 | _leave(" = 0 (picked %08x)", | |
339 | ntohl(server->addr.s_addr)); | |
340 | return 0; | |
341 | ||
342 | case -ENETUNREACH: | |
343 | if (ret == 0) | |
344 | ret = state; | |
345 | break; | |
346 | ||
347 | case -EHOSTUNREACH: | |
348 | if (ret == 0 || | |
349 | ret == -ENETUNREACH) | |
350 | ret = state; | |
351 | break; | |
352 | ||
353 | case -ECONNREFUSED: | |
354 | if (ret == 0 || | |
355 | ret == -ENETUNREACH || | |
356 | ret == -EHOSTUNREACH) | |
357 | ret = state; | |
358 | break; | |
359 | ||
360 | default: | |
361 | case -EREMOTEIO: | |
362 | if (ret == 0 || | |
363 | ret == -ENETUNREACH || | |
364 | ret == -EHOSTUNREACH || | |
365 | ret == -ECONNREFUSED) | |
366 | ret = state; | |
367 | break; | |
368 | } | |
369 | } | |
370 | ||
371 | /* no available servers | |
372 | * - TODO: handle the no active servers case better | |
373 | */ | |
374 | up_read(&volume->server_sem); | |
375 | _leave(" = %d", ret); | |
376 | return ret; | |
377 | } /* end afs_volume_pick_fileserver() */ | |
378 | ||
379 | /*****************************************************************************/ | |
380 | /* | |
381 | * release a server after use | |
382 | * - releases the ref on the server struct that was acquired by picking | |
383 | * - records result of using a particular server to access a volume | |
384 | * - return 0 to try again, 1 if okay or to issue error | |
385 | */ | |
386 | int afs_volume_release_fileserver(struct afs_volume *volume, | |
387 | struct afs_server *server, | |
388 | int result) | |
389 | { | |
390 | unsigned loop; | |
391 | ||
392 | _enter("%s,%08x,%d", | |
393 | volume->vlocation->vldb.name, ntohl(server->addr.s_addr), | |
394 | result); | |
395 | ||
396 | switch (result) { | |
397 | /* success */ | |
398 | case 0: | |
399 | server->fs_act_jif = jiffies; | |
400 | break; | |
401 | ||
402 | /* the fileserver denied all knowledge of the volume */ | |
403 | case -ENOMEDIUM: | |
404 | server->fs_act_jif = jiffies; | |
405 | down_write(&volume->server_sem); | |
406 | ||
407 | /* first, find where the server is in the active list (if it | |
408 | * is) */ | |
409 | for (loop = 0; loop < volume->nservers; loop++) | |
410 | if (volume->servers[loop] == server) | |
411 | goto present; | |
412 | ||
413 | /* no longer there - may have been discarded by another op */ | |
414 | goto try_next_server_upw; | |
415 | ||
416 | present: | |
417 | volume->nservers--; | |
418 | memmove(&volume->servers[loop], | |
419 | &volume->servers[loop + 1], | |
420 | sizeof(volume->servers[loop]) * | |
421 | (volume->nservers - loop)); | |
422 | volume->servers[volume->nservers] = NULL; | |
423 | afs_put_server(server); | |
424 | volume->rjservers++; | |
425 | ||
426 | if (volume->nservers > 0) | |
427 | /* another server might acknowledge its existence */ | |
428 | goto try_next_server_upw; | |
429 | ||
430 | /* handle the case where all the fileservers have rejected the | |
431 | * volume | |
432 | * - TODO: try asking the fileservers for volume information | |
433 | * - TODO: contact the VL server again to see if the volume is | |
434 | * no longer registered | |
435 | */ | |
436 | up_write(&volume->server_sem); | |
437 | afs_put_server(server); | |
438 | _leave(" [completely rejected]"); | |
439 | return 1; | |
440 | ||
441 | /* problem reaching the server */ | |
442 | case -ENETUNREACH: | |
443 | case -EHOSTUNREACH: | |
444 | case -ECONNREFUSED: | |
445 | case -ETIMEDOUT: | |
446 | case -EREMOTEIO: | |
447 | /* mark the server as dead | |
448 | * TODO: vary dead timeout depending on error | |
449 | */ | |
450 | spin_lock(&server->fs_lock); | |
451 | if (!server->fs_state) { | |
452 | server->fs_dead_jif = jiffies + HZ * 10; | |
453 | server->fs_state = result; | |
454 | printk("kAFS: SERVER DEAD state=%d\n", result); | |
455 | } | |
456 | spin_unlock(&server->fs_lock); | |
457 | goto try_next_server; | |
458 | ||
459 | /* miscellaneous error */ | |
460 | default: | |
461 | server->fs_act_jif = jiffies; | |
462 | case -ENOMEM: | |
463 | case -ENONET: | |
464 | break; | |
465 | } | |
466 | ||
467 | /* tell the caller to accept the result */ | |
468 | afs_put_server(server); | |
469 | _leave(""); | |
470 | return 1; | |
471 | ||
472 | /* tell the caller to loop around and try the next server */ | |
473 | try_next_server_upw: | |
474 | up_write(&volume->server_sem); | |
475 | try_next_server: | |
476 | afs_put_server(server); | |
477 | _leave(" [try next server]"); | |
478 | return 0; | |
479 | ||
480 | } /* end afs_volume_release_fileserver() */ | |
481 | ||
482 | /*****************************************************************************/ | |
483 | /* | |
484 | * match a volume hash record stored in the cache | |
485 | */ | |
486 | #ifdef AFS_CACHING_SUPPORT | |
487 | static cachefs_match_val_t afs_volume_cache_match(void *target, | |
488 | const void *entry) | |
489 | { | |
490 | const struct afs_cache_vhash *vhash = entry; | |
491 | struct afs_volume *volume = target; | |
492 | ||
493 | _enter("{%u},{%u}", volume->type, vhash->vtype); | |
494 | ||
495 | if (volume->type == vhash->vtype) { | |
496 | _leave(" = SUCCESS"); | |
497 | return CACHEFS_MATCH_SUCCESS; | |
498 | } | |
499 | ||
500 | _leave(" = FAILED"); | |
501 | return CACHEFS_MATCH_FAILED; | |
502 | } /* end afs_volume_cache_match() */ | |
503 | #endif | |
504 | ||
505 | /*****************************************************************************/ | |
506 | /* | |
507 | * update a volume hash record stored in the cache | |
508 | */ | |
509 | #ifdef AFS_CACHING_SUPPORT | |
510 | static void afs_volume_cache_update(void *source, void *entry) | |
511 | { | |
512 | struct afs_cache_vhash *vhash = entry; | |
513 | struct afs_volume *volume = source; | |
514 | ||
515 | _enter(""); | |
516 | ||
517 | vhash->vtype = volume->type; | |
518 | ||
519 | } /* end afs_volume_cache_update() */ | |
520 | #endif |