stmmac: fix a filter problem after resuming.
[linux/fpc-iii.git] / fs / autofs4 / waitq.c
blob35b755e79c2d9b311d0eb899dd749580cb42b209
1 /* -*- c -*- --------------------------------------------------------------- *
3 * linux/fs/autofs/waitq.c
5 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6 * Copyright 2001-2006 Ian Kent <raven@themaw.net>
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.
12 * ------------------------------------------------------------------------- */
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"
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;
24 /* These are the signals we allow interrupting a pending mount */
25 #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))
27 void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
29 struct autofs_wait_queue *wq, *nwq;
31 mutex_lock(&sbi->wq_mutex);
32 if (sbi->catatonic) {
33 mutex_unlock(&sbi->wq_mutex);
34 return;
37 DPRINTK("entering catatonic mode");
39 sbi->catatonic = 1;
40 wq = sbi->queues;
41 sbi->queues = NULL; /* Erase all wait queues */
42 while (wq) {
43 nwq = wq->next;
44 wq->status = -ENOENT; /* Magic is gone - report failure */
45 kfree(wq->name.name);
46 wq->name.name = NULL;
47 wq->wait_ctr--;
48 wake_up_interruptible(&wq->queue);
49 wq = nwq;
51 fput(sbi->pipe); /* Close the pipe */
52 sbi->pipe = NULL;
53 sbi->pipefd = -1;
54 mutex_unlock(&sbi->wq_mutex);
57 static int autofs4_write(struct autofs_sb_info *sbi,
58 struct file *file, const void *addr, int bytes)
60 unsigned long sigpipe, flags;
61 mm_segment_t fs;
62 const char *data = (const char *)addr;
63 ssize_t wr = 0;
65 sigpipe = sigismember(&current->pending.signal, SIGPIPE);
67 /* Save pointer to user space and point back to kernel space */
68 fs = get_fs();
69 set_fs(KERNEL_DS);
71 mutex_lock(&sbi->pipe_mutex);
72 while (bytes &&
73 (wr = __vfs_write(file,data,bytes,&file->f_pos)) > 0) {
74 data += wr;
75 bytes -= wr;
77 mutex_unlock(&sbi->pipe_mutex);
79 set_fs(fs);
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(&current->sighand->siglock, flags);
85 sigdelset(&current->pending.signal, SIGPIPE);
86 recalc_sigpending();
87 spin_unlock_irqrestore(&current->sighand->siglock, flags);
90 return (bytes > 0);
93 static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
94 struct autofs_wait_queue *wq,
95 int type)
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;
102 struct file *pipe = NULL;
103 size_t pktsz;
105 DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
106 (unsigned long) wq->wait_queue_token, wq->name.len, wq->name.name, type);
108 memset(&pkt,0,sizeof pkt); /* For security reasons */
110 pkt.hdr.proto_version = sbi->version;
111 pkt.hdr.type = type;
113 switch (type) {
114 /* Kernel protocol v4 missing and expire packets */
115 case autofs_ptype_missing:
117 struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
119 pktsz = sizeof(*mp);
121 mp->wait_queue_token = wq->wait_queue_token;
122 mp->len = wq->name.len;
123 memcpy(mp->name, wq->name.name, wq->name.len);
124 mp->name[wq->name.len] = '\0';
125 break;
127 case autofs_ptype_expire_multi:
129 struct autofs_packet_expire_multi *ep = &pkt.v4_pkt.expire_multi;
131 pktsz = sizeof(*ep);
133 ep->wait_queue_token = wq->wait_queue_token;
134 ep->len = wq->name.len;
135 memcpy(ep->name, wq->name.name, wq->name.len);
136 ep->name[wq->name.len] = '\0';
137 break;
140 * Kernel protocol v5 packet for handling indirect and direct
141 * mount missing and expire requests
143 case autofs_ptype_missing_indirect:
144 case autofs_ptype_expire_indirect:
145 case autofs_ptype_missing_direct:
146 case autofs_ptype_expire_direct:
148 struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
149 struct user_namespace *user_ns = sbi->pipe->f_cred->user_ns;
151 pktsz = sizeof(*packet);
153 packet->wait_queue_token = wq->wait_queue_token;
154 packet->len = wq->name.len;
155 memcpy(packet->name, wq->name.name, wq->name.len);
156 packet->name[wq->name.len] = '\0';
157 packet->dev = wq->dev;
158 packet->ino = wq->ino;
159 packet->uid = from_kuid_munged(user_ns, wq->uid);
160 packet->gid = from_kgid_munged(user_ns, wq->gid);
161 packet->pid = wq->pid;
162 packet->tgid = wq->tgid;
163 break;
165 default:
166 printk("autofs4_notify_daemon: bad type %d!\n", type);
167 mutex_unlock(&sbi->wq_mutex);
168 return;
171 pipe = get_file(sbi->pipe);
173 mutex_unlock(&sbi->wq_mutex);
175 if (autofs4_write(sbi, pipe, &pkt, pktsz))
176 autofs4_catatonic_mode(sbi);
177 fput(pipe);
180 static int autofs4_getpath(struct autofs_sb_info *sbi,
181 struct dentry *dentry, char **name)
183 struct dentry *root = sbi->sb->s_root;
184 struct dentry *tmp;
185 char *buf;
186 char *p;
187 int len;
188 unsigned seq;
190 rename_retry:
191 buf = *name;
192 len = 0;
194 seq = read_seqbegin(&rename_lock);
195 rcu_read_lock();
196 spin_lock(&sbi->fs_lock);
197 for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
198 len += tmp->d_name.len + 1;
200 if (!len || --len > NAME_MAX) {
201 spin_unlock(&sbi->fs_lock);
202 rcu_read_unlock();
203 if (read_seqretry(&rename_lock, seq))
204 goto rename_retry;
205 return 0;
208 *(buf + len) = '\0';
209 p = buf + len - dentry->d_name.len;
210 strncpy(p, dentry->d_name.name, dentry->d_name.len);
212 for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
213 *(--p) = '/';
214 p -= tmp->d_name.len;
215 strncpy(p, tmp->d_name.name, tmp->d_name.len);
217 spin_unlock(&sbi->fs_lock);
218 rcu_read_unlock();
219 if (read_seqretry(&rename_lock, seq))
220 goto rename_retry;
222 return len;
225 static struct autofs_wait_queue *
226 autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr)
228 struct autofs_wait_queue *wq;
230 for (wq = sbi->queues; wq; wq = wq->next) {
231 if (wq->name.hash == qstr->hash &&
232 wq->name.len == qstr->len &&
233 wq->name.name &&
234 !memcmp(wq->name.name, qstr->name, qstr->len))
235 break;
237 return wq;
241 * Check if we have a valid request.
242 * Returns
243 * 1 if the request should continue.
244 * In this case we can return an autofs_wait_queue entry if one is
245 * found or NULL to idicate a new wait needs to be created.
246 * 0 or a negative errno if the request shouldn't continue.
248 static int validate_request(struct autofs_wait_queue **wait,
249 struct autofs_sb_info *sbi,
250 struct qstr *qstr,
251 struct dentry*dentry, enum autofs_notify notify)
253 struct autofs_wait_queue *wq;
254 struct autofs_info *ino;
256 if (sbi->catatonic)
257 return -ENOENT;
259 /* Wait in progress, continue; */
260 wq = autofs4_find_wait(sbi, qstr);
261 if (wq) {
262 *wait = wq;
263 return 1;
266 *wait = NULL;
268 /* If we don't yet have any info this is a new request */
269 ino = autofs4_dentry_ino(dentry);
270 if (!ino)
271 return 1;
274 * If we've been asked to wait on an existing expire (NFY_NONE)
275 * but there is no wait in the queue ...
277 if (notify == NFY_NONE) {
279 * Either we've betean the pending expire to post it's
280 * wait or it finished while we waited on the mutex.
281 * So we need to wait till either, the wait appears
282 * or the expire finishes.
285 while (ino->flags & AUTOFS_INF_EXPIRING) {
286 mutex_unlock(&sbi->wq_mutex);
287 schedule_timeout_interruptible(HZ/10);
288 if (mutex_lock_interruptible(&sbi->wq_mutex))
289 return -EINTR;
291 if (sbi->catatonic)
292 return -ENOENT;
294 wq = autofs4_find_wait(sbi, qstr);
295 if (wq) {
296 *wait = wq;
297 return 1;
302 * Not ideal but the status has already gone. Of the two
303 * cases where we wait on NFY_NONE neither depend on the
304 * return status of the wait.
306 return 0;
310 * If we've been asked to trigger a mount and the request
311 * completed while we waited on the mutex ...
313 if (notify == NFY_MOUNT) {
314 struct dentry *new = NULL;
315 int valid = 1;
318 * If the dentry was successfully mounted while we slept
319 * on the wait queue mutex we can return success. If it
320 * isn't mounted (doesn't have submounts for the case of
321 * a multi-mount with no mount at it's base) we can
322 * continue on and create a new request.
324 if (!IS_ROOT(dentry)) {
325 if (d_really_is_positive(dentry) && d_unhashed(dentry)) {
326 struct dentry *parent = dentry->d_parent;
327 new = d_lookup(parent, &dentry->d_name);
328 if (new)
329 dentry = new;
332 if (have_submounts(dentry))
333 valid = 0;
335 if (new)
336 dput(new);
337 return valid;
340 return 1;
343 int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
344 enum autofs_notify notify)
346 struct autofs_wait_queue *wq;
347 struct qstr qstr;
348 char *name;
349 int status, ret, type;
350 pid_t pid;
351 pid_t tgid;
353 /* In catatonic mode, we don't wait for nobody */
354 if (sbi->catatonic)
355 return -ENOENT;
358 * Try translating pids to the namespace of the daemon.
360 * Zero means failure: we are in an unrelated pid namespace.
362 pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
363 tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
364 if (pid == 0 || tgid == 0)
365 return -ENOENT;
367 if (d_really_is_negative(dentry)) {
369 * A wait for a negative dentry is invalid for certain
370 * cases. A direct or offset mount "always" has its mount
371 * point directory created and so the request dentry must
372 * be positive or the map key doesn't exist. The situation
373 * is very similar for indirect mounts except only dentrys
374 * in the root of the autofs file system may be negative.
376 if (autofs_type_trigger(sbi->type))
377 return -ENOENT;
378 else if (!IS_ROOT(dentry->d_parent))
379 return -ENOENT;
382 name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
383 if (!name)
384 return -ENOMEM;
386 /* If this is a direct mount request create a dummy name */
387 if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
388 qstr.len = sprintf(name, "%p", dentry);
389 else {
390 qstr.len = autofs4_getpath(sbi, dentry, &name);
391 if (!qstr.len) {
392 kfree(name);
393 return -ENOENT;
396 qstr.name = name;
397 qstr.hash = full_name_hash(name, qstr.len);
399 if (mutex_lock_interruptible(&sbi->wq_mutex)) {
400 kfree(qstr.name);
401 return -EINTR;
404 ret = validate_request(&wq, sbi, &qstr, dentry, notify);
405 if (ret <= 0) {
406 if (ret != -EINTR)
407 mutex_unlock(&sbi->wq_mutex);
408 kfree(qstr.name);
409 return ret;
412 if (!wq) {
413 /* Create a new wait queue */
414 wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
415 if (!wq) {
416 kfree(qstr.name);
417 mutex_unlock(&sbi->wq_mutex);
418 return -ENOMEM;
421 wq->wait_queue_token = autofs4_next_wait_queue;
422 if (++autofs4_next_wait_queue == 0)
423 autofs4_next_wait_queue = 1;
424 wq->next = sbi->queues;
425 sbi->queues = wq;
426 init_waitqueue_head(&wq->queue);
427 memcpy(&wq->name, &qstr, sizeof(struct qstr));
428 wq->dev = autofs4_get_dev(sbi);
429 wq->ino = autofs4_get_ino(sbi);
430 wq->uid = current_uid();
431 wq->gid = current_gid();
432 wq->pid = pid;
433 wq->tgid = tgid;
434 wq->status = -EINTR; /* Status return if interrupted */
435 wq->wait_ctr = 2;
437 if (sbi->version < 5) {
438 if (notify == NFY_MOUNT)
439 type = autofs_ptype_missing;
440 else
441 type = autofs_ptype_expire_multi;
442 } else {
443 if (notify == NFY_MOUNT)
444 type = autofs_type_trigger(sbi->type) ?
445 autofs_ptype_missing_direct :
446 autofs_ptype_missing_indirect;
447 else
448 type = autofs_type_trigger(sbi->type) ?
449 autofs_ptype_expire_direct :
450 autofs_ptype_expire_indirect;
453 DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
454 (unsigned long) wq->wait_queue_token, wq->name.len,
455 wq->name.name, notify);
457 /* autofs4_notify_daemon() may block; it will unlock ->wq_mutex */
458 autofs4_notify_daemon(sbi, wq, type);
459 } else {
460 wq->wait_ctr++;
461 DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
462 (unsigned long) wq->wait_queue_token, wq->name.len,
463 wq->name.name, notify);
464 mutex_unlock(&sbi->wq_mutex);
465 kfree(qstr.name);
469 * wq->name.name is NULL iff the lock is already released
470 * or the mount has been made catatonic.
472 if (wq->name.name) {
473 /* Block all but "shutdown" signals while waiting */
474 sigset_t oldset;
475 unsigned long irqflags;
477 spin_lock_irqsave(&current->sighand->siglock, irqflags);
478 oldset = current->blocked;
479 siginitsetinv(&current->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
480 recalc_sigpending();
481 spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
483 wait_event_interruptible(wq->queue, wq->name.name == NULL);
485 spin_lock_irqsave(&current->sighand->siglock, irqflags);
486 current->blocked = oldset;
487 recalc_sigpending();
488 spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
489 } else {
490 DPRINTK("skipped sleeping");
493 status = wq->status;
496 * For direct and offset mounts we need to track the requester's
497 * uid and gid in the dentry info struct. This is so it can be
498 * supplied, on request, by the misc device ioctl interface.
499 * This is needed during daemon resatart when reconnecting
500 * to existing, active, autofs mounts. The uid and gid (and
501 * related string values) may be used for macro substitution
502 * in autofs mount maps.
504 if (!status) {
505 struct autofs_info *ino;
506 struct dentry *de = NULL;
508 /* direct mount or browsable map */
509 ino = autofs4_dentry_ino(dentry);
510 if (!ino) {
511 /* If not lookup actual dentry used */
512 de = d_lookup(dentry->d_parent, &dentry->d_name);
513 if (de)
514 ino = autofs4_dentry_ino(de);
517 /* Set mount requester */
518 if (ino) {
519 spin_lock(&sbi->fs_lock);
520 ino->uid = wq->uid;
521 ino->gid = wq->gid;
522 spin_unlock(&sbi->fs_lock);
525 if (de)
526 dput(de);
529 /* Are we the last process to need status? */
530 mutex_lock(&sbi->wq_mutex);
531 if (!--wq->wait_ctr)
532 kfree(wq);
533 mutex_unlock(&sbi->wq_mutex);
535 return status;
539 int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
541 struct autofs_wait_queue *wq, **wql;
543 mutex_lock(&sbi->wq_mutex);
544 for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
545 if (wq->wait_queue_token == wait_queue_token)
546 break;
549 if (!wq) {
550 mutex_unlock(&sbi->wq_mutex);
551 return -EINVAL;
554 *wql = wq->next; /* Unlink from chain */
555 kfree(wq->name.name);
556 wq->name.name = NULL; /* Do not wait on this queue */
557 wq->status = status;
558 wake_up_interruptible(&wq->queue);
559 if (!--wq->wait_ctr)
560 kfree(wq);
561 mutex_unlock(&sbi->wq_mutex);
563 return 0;