Commit | Line | Data |
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1da177e4 LT |
1 | /* -*- c -*- --------------------------------------------------------------- * |
2 | * | |
3 | * linux/fs/autofs/waitq.c | |
4 | * | |
5 | * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved | |
5c0a32fc | 6 | * Copyright 2001-2006 Ian Kent <raven@themaw.net> |
1da177e4 LT |
7 | * |
8 | * This file is part of the Linux kernel and is made available under | |
9 | * the terms of the GNU General Public License, version 2, or at your | |
10 | * option, any later version, incorporated herein by reference. | |
11 | * | |
12 | * ------------------------------------------------------------------------- */ | |
13 | ||
14 | #include <linux/slab.h> | |
15 | #include <linux/time.h> | |
16 | #include <linux/signal.h> | |
17 | #include <linux/file.h> | |
18 | #include "autofs_i.h" | |
19 | ||
20 | /* We make this a static variable rather than a part of the superblock; it | |
21 | is better if we don't reassign numbers easily even across filesystems */ | |
22 | static autofs_wqt_t autofs4_next_wait_queue = 1; | |
23 | ||
24 | /* These are the signals we allow interrupting a pending mount */ | |
25 | #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT)) | |
26 | ||
27 | void autofs4_catatonic_mode(struct autofs_sb_info *sbi) | |
28 | { | |
29 | struct autofs_wait_queue *wq, *nwq; | |
30 | ||
5a11d4d0 IK |
31 | mutex_lock(&sbi->wq_mutex); |
32 | if (sbi->catatonic) { | |
33 | mutex_unlock(&sbi->wq_mutex); | |
34 | return; | |
35 | } | |
36 | ||
1da177e4 LT |
37 | DPRINTK("entering catatonic mode"); |
38 | ||
39 | sbi->catatonic = 1; | |
40 | wq = sbi->queues; | |
41 | sbi->queues = NULL; /* Erase all wait queues */ | |
e77fbddf | 42 | while (wq) { |
1da177e4 LT |
43 | nwq = wq->next; |
44 | wq->status = -ENOENT; /* Magic is gone - report failure */ | |
70b52a0a JM |
45 | if (wq->name.name) { |
46 | kfree(wq->name.name); | |
47 | wq->name.name = NULL; | |
48 | } | |
1da177e4 LT |
49 | wake_up_interruptible(&wq->queue); |
50 | wq = nwq; | |
51 | } | |
ba8df43c IK |
52 | fput(sbi->pipe); /* Close the pipe */ |
53 | sbi->pipe = NULL; | |
5a11d4d0 IK |
54 | sbi->pipefd = -1; |
55 | mutex_unlock(&sbi->wq_mutex); | |
1da177e4 LT |
56 | } |
57 | ||
58 | static int autofs4_write(struct file *file, const void *addr, int bytes) | |
59 | { | |
60 | unsigned long sigpipe, flags; | |
61 | mm_segment_t fs; | |
62 | const char *data = (const char *)addr; | |
63 | ssize_t wr = 0; | |
64 | ||
65 | /** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/ | |
66 | ||
67 | sigpipe = sigismember(¤t->pending.signal, SIGPIPE); | |
68 | ||
69 | /* Save pointer to user space and point back to kernel space */ | |
70 | fs = get_fs(); | |
71 | set_fs(KERNEL_DS); | |
72 | ||
73 | while (bytes && | |
74 | (wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) { | |
75 | data += wr; | |
76 | bytes -= wr; | |
77 | } | |
78 | ||
79 | set_fs(fs); | |
80 | ||
81 | /* Keep the currently executing process from receiving a | |
82 | SIGPIPE unless it was already supposed to get one */ | |
83 | if (wr == -EPIPE && !sigpipe) { | |
84 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
85 | sigdelset(¤t->pending.signal, SIGPIPE); | |
86 | recalc_sigpending(); | |
87 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
88 | } | |
89 | ||
90 | return (bytes > 0); | |
91 | } | |
92 | ||
93 | static void autofs4_notify_daemon(struct autofs_sb_info *sbi, | |
94 | struct autofs_wait_queue *wq, | |
95 | int type) | |
96 | { | |
e8514478 IK |
97 | union { |
98 | struct autofs_packet_hdr hdr; | |
99 | union autofs_packet_union v4_pkt; | |
100 | union autofs_v5_packet_union v5_pkt; | |
101 | } pkt; | |
1da177e4 LT |
102 | size_t pktsz; |
103 | ||
104 | DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d", | |
70b52a0a | 105 | wq->wait_queue_token, wq->name.len, wq->name.name, type); |
1da177e4 LT |
106 | |
107 | memset(&pkt,0,sizeof pkt); /* For security reasons */ | |
108 | ||
109 | pkt.hdr.proto_version = sbi->version; | |
110 | pkt.hdr.type = type; | |
5c0a32fc IK |
111 | switch (type) { |
112 | /* Kernel protocol v4 missing and expire packets */ | |
113 | case autofs_ptype_missing: | |
114 | { | |
e8514478 | 115 | struct autofs_packet_missing *mp = &pkt.v4_pkt.missing; |
1da177e4 LT |
116 | |
117 | pktsz = sizeof(*mp); | |
118 | ||
119 | mp->wait_queue_token = wq->wait_queue_token; | |
70b52a0a JM |
120 | mp->len = wq->name.len; |
121 | memcpy(mp->name, wq->name.name, wq->name.len); | |
122 | mp->name[wq->name.len] = '\0'; | |
5c0a32fc IK |
123 | break; |
124 | } | |
125 | case autofs_ptype_expire_multi: | |
126 | { | |
e8514478 | 127 | struct autofs_packet_expire_multi *ep = &pkt.v4_pkt.expire_multi; |
1da177e4 LT |
128 | |
129 | pktsz = sizeof(*ep); | |
130 | ||
131 | ep->wait_queue_token = wq->wait_queue_token; | |
70b52a0a JM |
132 | ep->len = wq->name.len; |
133 | memcpy(ep->name, wq->name.name, wq->name.len); | |
134 | ep->name[wq->name.len] = '\0'; | |
5c0a32fc IK |
135 | break; |
136 | } | |
137 | /* | |
138 | * Kernel protocol v5 packet for handling indirect and direct | |
139 | * mount missing and expire requests | |
140 | */ | |
141 | case autofs_ptype_missing_indirect: | |
142 | case autofs_ptype_expire_indirect: | |
143 | case autofs_ptype_missing_direct: | |
144 | case autofs_ptype_expire_direct: | |
145 | { | |
e8514478 | 146 | struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet; |
5c0a32fc IK |
147 | |
148 | pktsz = sizeof(*packet); | |
149 | ||
150 | packet->wait_queue_token = wq->wait_queue_token; | |
70b52a0a JM |
151 | packet->len = wq->name.len; |
152 | memcpy(packet->name, wq->name.name, wq->name.len); | |
153 | packet->name[wq->name.len] = '\0'; | |
5c0a32fc IK |
154 | packet->dev = wq->dev; |
155 | packet->ino = wq->ino; | |
156 | packet->uid = wq->uid; | |
157 | packet->gid = wq->gid; | |
158 | packet->pid = wq->pid; | |
159 | packet->tgid = wq->tgid; | |
160 | break; | |
161 | } | |
162 | default: | |
1da177e4 LT |
163 | printk("autofs4_notify_daemon: bad type %d!\n", type); |
164 | return; | |
165 | } | |
166 | ||
167 | if (autofs4_write(sbi->pipe, &pkt, pktsz)) | |
168 | autofs4_catatonic_mode(sbi); | |
169 | } | |
170 | ||
171 | static int autofs4_getpath(struct autofs_sb_info *sbi, | |
172 | struct dentry *dentry, char **name) | |
173 | { | |
174 | struct dentry *root = sbi->sb->s_root; | |
175 | struct dentry *tmp; | |
176 | char *buf = *name; | |
177 | char *p; | |
178 | int len = 0; | |
179 | ||
180 | spin_lock(&dcache_lock); | |
181 | for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent) | |
182 | len += tmp->d_name.len + 1; | |
183 | ||
cab0936a | 184 | if (!len || --len > NAME_MAX) { |
1da177e4 LT |
185 | spin_unlock(&dcache_lock); |
186 | return 0; | |
187 | } | |
188 | ||
189 | *(buf + len) = '\0'; | |
190 | p = buf + len - dentry->d_name.len; | |
191 | strncpy(p, dentry->d_name.name, dentry->d_name.len); | |
192 | ||
193 | for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) { | |
194 | *(--p) = '/'; | |
195 | p -= tmp->d_name.len; | |
196 | strncpy(p, tmp->d_name.name, tmp->d_name.len); | |
197 | } | |
198 | spin_unlock(&dcache_lock); | |
199 | ||
200 | return len; | |
201 | } | |
202 | ||
a5370553 | 203 | static struct autofs_wait_queue * |
70b52a0a | 204 | autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr) |
a5370553 IK |
205 | { |
206 | struct autofs_wait_queue *wq; | |
207 | ||
208 | for (wq = sbi->queues; wq; wq = wq->next) { | |
70b52a0a JM |
209 | if (wq->name.hash == qstr->hash && |
210 | wq->name.len == qstr->len && | |
211 | wq->name.name && | |
212 | !memcmp(wq->name.name, qstr->name, qstr->len)) | |
a5370553 IK |
213 | break; |
214 | } | |
215 | return wq; | |
216 | } | |
217 | ||
a1362fe9 IK |
218 | /* |
219 | * Check if we have a valid request. | |
220 | * Returns | |
221 | * 1 if the request should continue. | |
222 | * In this case we can return an autofs_wait_queue entry if one is | |
223 | * found or NULL to idicate a new wait needs to be created. | |
224 | * 0 or a negative errno if the request shouldn't continue. | |
225 | */ | |
226 | static int validate_request(struct autofs_wait_queue **wait, | |
227 | struct autofs_sb_info *sbi, | |
228 | struct qstr *qstr, | |
229 | struct dentry*dentry, enum autofs_notify notify) | |
230 | { | |
231 | struct autofs_wait_queue *wq; | |
232 | struct autofs_info *ino; | |
233 | ||
234 | /* Wait in progress, continue; */ | |
235 | wq = autofs4_find_wait(sbi, qstr); | |
236 | if (wq) { | |
237 | *wait = wq; | |
238 | return 1; | |
239 | } | |
240 | ||
241 | *wait = NULL; | |
242 | ||
243 | /* If we don't yet have any info this is a new request */ | |
244 | ino = autofs4_dentry_ino(dentry); | |
245 | if (!ino) | |
246 | return 1; | |
247 | ||
248 | /* | |
249 | * If we've been asked to wait on an existing expire (NFY_NONE) | |
250 | * but there is no wait in the queue ... | |
251 | */ | |
252 | if (notify == NFY_NONE) { | |
253 | /* | |
254 | * Either we've betean the pending expire to post it's | |
255 | * wait or it finished while we waited on the mutex. | |
256 | * So we need to wait till either, the wait appears | |
257 | * or the expire finishes. | |
258 | */ | |
259 | ||
260 | while (ino->flags & AUTOFS_INF_EXPIRING) { | |
261 | mutex_unlock(&sbi->wq_mutex); | |
262 | schedule_timeout_interruptible(HZ/10); | |
263 | if (mutex_lock_interruptible(&sbi->wq_mutex)) | |
264 | return -EINTR; | |
265 | ||
266 | wq = autofs4_find_wait(sbi, qstr); | |
267 | if (wq) { | |
268 | *wait = wq; | |
269 | return 1; | |
270 | } | |
271 | } | |
272 | ||
273 | /* | |
274 | * Not ideal but the status has already gone. Of the two | |
275 | * cases where we wait on NFY_NONE neither depend on the | |
276 | * return status of the wait. | |
277 | */ | |
278 | return 0; | |
279 | } | |
280 | ||
281 | /* | |
282 | * If we've been asked to trigger a mount and the request | |
283 | * completed while we waited on the mutex ... | |
284 | */ | |
285 | if (notify == NFY_MOUNT) { | |
286 | /* | |
287 | * If the dentry isn't hashed just go ahead and try the | |
288 | * mount again with a new wait (not much else we can do). | |
289 | */ | |
290 | if (!d_unhashed(dentry)) { | |
291 | /* | |
292 | * But if the dentry is hashed, that means that we | |
293 | * got here through the revalidate path. Thus, we | |
294 | * need to check if the dentry has been mounted | |
295 | * while we waited on the wq_mutex. If it has, | |
296 | * simply return success. | |
297 | */ | |
298 | if (d_mountpoint(dentry)) | |
299 | return 0; | |
300 | } | |
301 | } | |
302 | ||
303 | return 1; | |
304 | } | |
305 | ||
1da177e4 LT |
306 | int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry, |
307 | enum autofs_notify notify) | |
308 | { | |
309 | struct autofs_wait_queue *wq; | |
70b52a0a | 310 | struct qstr qstr; |
1da177e4 | 311 | char *name; |
a1362fe9 | 312 | int status, ret, type; |
1da177e4 LT |
313 | |
314 | /* In catatonic mode, we don't wait for nobody */ | |
e77fbddf | 315 | if (sbi->catatonic) |
1da177e4 | 316 | return -ENOENT; |
a1362fe9 | 317 | |
1da177e4 LT |
318 | name = kmalloc(NAME_MAX + 1, GFP_KERNEL); |
319 | if (!name) | |
320 | return -ENOMEM; | |
321 | ||
5c0a32fc | 322 | /* If this is a direct mount request create a dummy name */ |
44d53eb0 | 323 | if (IS_ROOT(dentry) && (sbi->type & AUTOFS_TYPE_DIRECT)) |
70b52a0a | 324 | qstr.len = sprintf(name, "%p", dentry); |
5c0a32fc | 325 | else { |
70b52a0a JM |
326 | qstr.len = autofs4_getpath(sbi, dentry, &name); |
327 | if (!qstr.len) { | |
5c0a32fc IK |
328 | kfree(name); |
329 | return -ENOENT; | |
330 | } | |
1da177e4 | 331 | } |
70b52a0a JM |
332 | qstr.name = name; |
333 | qstr.hash = full_name_hash(name, qstr.len); | |
1da177e4 | 334 | |
a1362fe9 | 335 | if (mutex_lock_interruptible(&sbi->wq_mutex)) |
1da177e4 | 336 | return -EINTR; |
a5370553 | 337 | |
a1362fe9 IK |
338 | ret = validate_request(&wq, sbi, &qstr, dentry, notify); |
339 | if (ret <= 0) { | |
340 | if (ret == 0) | |
1d5599e3 | 341 | mutex_unlock(&sbi->wq_mutex); |
a1362fe9 IK |
342 | kfree(qstr.name); |
343 | return ret; | |
a5370553 | 344 | } |
cc9acc88 | 345 | |
a5370553 | 346 | if (!wq) { |
1da177e4 LT |
347 | /* Create a new wait queue */ |
348 | wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL); | |
e77fbddf | 349 | if (!wq) { |
70b52a0a | 350 | kfree(qstr.name); |
1d5599e3 | 351 | mutex_unlock(&sbi->wq_mutex); |
1da177e4 LT |
352 | return -ENOMEM; |
353 | } | |
354 | ||
355 | wq->wait_queue_token = autofs4_next_wait_queue; | |
356 | if (++autofs4_next_wait_queue == 0) | |
357 | autofs4_next_wait_queue = 1; | |
358 | wq->next = sbi->queues; | |
359 | sbi->queues = wq; | |
360 | init_waitqueue_head(&wq->queue); | |
70b52a0a | 361 | memcpy(&wq->name, &qstr, sizeof(struct qstr)); |
5c0a32fc IK |
362 | wq->dev = autofs4_get_dev(sbi); |
363 | wq->ino = autofs4_get_ino(sbi); | |
364 | wq->uid = current->uid; | |
365 | wq->gid = current->gid; | |
366 | wq->pid = current->pid; | |
367 | wq->tgid = current->tgid; | |
1da177e4 LT |
368 | wq->status = -EINTR; /* Status return if interrupted */ |
369 | atomic_set(&wq->wait_ctr, 2); | |
1d5599e3 | 370 | mutex_unlock(&sbi->wq_mutex); |
3e7b1919 | 371 | |
5c0a32fc IK |
372 | if (sbi->version < 5) { |
373 | if (notify == NFY_MOUNT) | |
374 | type = autofs_ptype_missing; | |
375 | else | |
376 | type = autofs_ptype_expire_multi; | |
377 | } else { | |
378 | if (notify == NFY_MOUNT) | |
44d53eb0 | 379 | type = (sbi->type & AUTOFS_TYPE_DIRECT) ? |
5c0a32fc IK |
380 | autofs_ptype_missing_direct : |
381 | autofs_ptype_missing_indirect; | |
382 | else | |
44d53eb0 | 383 | type = (sbi->type & AUTOFS_TYPE_DIRECT) ? |
5c0a32fc IK |
384 | autofs_ptype_expire_direct : |
385 | autofs_ptype_expire_indirect; | |
386 | } | |
4dcd00b1 | 387 | |
682d4fc9 | 388 | DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n", |
70b52a0a JM |
389 | (unsigned long) wq->wait_queue_token, wq->name.len, |
390 | wq->name.name, notify); | |
4dcd00b1 IK |
391 | |
392 | /* autofs4_notify_daemon() may block */ | |
393 | autofs4_notify_daemon(sbi, wq, type); | |
a5370553 IK |
394 | } else { |
395 | atomic_inc(&wq->wait_ctr); | |
396 | mutex_unlock(&sbi->wq_mutex); | |
70b52a0a | 397 | kfree(qstr.name); |
a5370553 | 398 | DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d", |
70b52a0a JM |
399 | (unsigned long) wq->wait_queue_token, wq->name.len, |
400 | wq->name.name, notify); | |
4dcd00b1 IK |
401 | } |
402 | ||
5a11d4d0 IK |
403 | /* |
404 | * wq->name.name is NULL iff the lock is already released | |
405 | * or the mount has been made catatonic. | |
406 | */ | |
70b52a0a | 407 | if (wq->name.name) { |
1da177e4 LT |
408 | /* Block all but "shutdown" signals while waiting */ |
409 | sigset_t oldset; | |
410 | unsigned long irqflags; | |
411 | ||
412 | spin_lock_irqsave(¤t->sighand->siglock, irqflags); | |
413 | oldset = current->blocked; | |
414 | siginitsetinv(¤t->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]); | |
415 | recalc_sigpending(); | |
416 | spin_unlock_irqrestore(¤t->sighand->siglock, irqflags); | |
417 | ||
70b52a0a | 418 | wait_event_interruptible(wq->queue, wq->name.name == NULL); |
1da177e4 LT |
419 | |
420 | spin_lock_irqsave(¤t->sighand->siglock, irqflags); | |
421 | current->blocked = oldset; | |
422 | recalc_sigpending(); | |
423 | spin_unlock_irqrestore(¤t->sighand->siglock, irqflags); | |
424 | } else { | |
425 | DPRINTK("skipped sleeping"); | |
426 | } | |
427 | ||
428 | status = wq->status; | |
429 | ||
430 | /* Are we the last process to need status? */ | |
431 | if (atomic_dec_and_test(&wq->wait_ctr)) | |
432 | kfree(wq); | |
433 | ||
434 | return status; | |
435 | } | |
436 | ||
437 | ||
438 | int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status) | |
439 | { | |
440 | struct autofs_wait_queue *wq, **wql; | |
441 | ||
1d5599e3 | 442 | mutex_lock(&sbi->wq_mutex); |
c80544dc | 443 | for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) { |
e77fbddf | 444 | if (wq->wait_queue_token == wait_queue_token) |
1da177e4 LT |
445 | break; |
446 | } | |
447 | ||
e77fbddf | 448 | if (!wq) { |
1d5599e3 | 449 | mutex_unlock(&sbi->wq_mutex); |
1da177e4 LT |
450 | return -EINVAL; |
451 | } | |
452 | ||
453 | *wql = wq->next; /* Unlink from chain */ | |
70b52a0a JM |
454 | kfree(wq->name.name); |
455 | wq->name.name = NULL; /* Do not wait on this queue */ | |
a1362fe9 | 456 | mutex_unlock(&sbi->wq_mutex); |
1da177e4 LT |
457 | |
458 | wq->status = status; | |
459 | ||
460 | if (atomic_dec_and_test(&wq->wait_ctr)) /* Is anyone still waiting for this guy? */ | |
461 | kfree(wq); | |
462 | else | |
463 | wake_up_interruptible(&wq->queue); | |
464 | ||
465 | return 0; | |
466 | } | |
467 |