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>
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);
33 mutex_unlock(&sbi->wq_mutex);
37 DPRINTK("entering catatonic mode");
41 sbi->queues = NULL; /* Erase all wait queues */
44 wq->status = -ENOENT; /* Magic is gone - report failure */
50 wake_up_interruptible(&wq->queue);
53 fput(sbi->pipe); /* Close the pipe */
56 mutex_unlock(&sbi->wq_mutex);
59 static int autofs4_write(struct autofs_sb_info *sbi,
60 struct file *file, const void *addr, int bytes)
62 unsigned long sigpipe, flags;
64 const char *data = (const char *)addr;
67 sigpipe = sigismember(¤t->pending.signal, SIGPIPE);
69 /* Save pointer to user space and point back to kernel space */
73 mutex_lock(&sbi->pipe_mutex);
75 (wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) {
79 mutex_unlock(&sbi->pipe_mutex);
83 /* Keep the currently executing process from receiving a
84 SIGPIPE unless it was already supposed to get one */
85 if (wr == -EPIPE && !sigpipe) {
86 spin_lock_irqsave(¤t->sighand->siglock, flags);
87 sigdelset(¤t->pending.signal, SIGPIPE);
89 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
95 static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
96 struct autofs_wait_queue *wq,
100 struct autofs_packet_hdr hdr;
101 union autofs_packet_union v4_pkt;
102 union autofs_v5_packet_union v5_pkt;
104 struct file *pipe = NULL;
107 DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
108 (unsigned long) wq->wait_queue_token, wq->name.len, wq->name.name, type);
110 memset(&pkt,0,sizeof pkt); /* For security reasons */
112 pkt.hdr.proto_version = sbi->version;
114 mutex_lock(&sbi->wq_mutex);
116 /* Check if we have become catatonic */
117 if (sbi->catatonic) {
118 mutex_unlock(&sbi->wq_mutex);
122 /* Kernel protocol v4 missing and expire packets */
123 case autofs_ptype_missing:
125 struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
129 mp->wait_queue_token = wq->wait_queue_token;
130 mp->len = wq->name.len;
131 memcpy(mp->name, wq->name.name, wq->name.len);
132 mp->name[wq->name.len] = '\0';
135 case autofs_ptype_expire_multi:
137 struct autofs_packet_expire_multi *ep = &pkt.v4_pkt.expire_multi;
141 ep->wait_queue_token = wq->wait_queue_token;
142 ep->len = wq->name.len;
143 memcpy(ep->name, wq->name.name, wq->name.len);
144 ep->name[wq->name.len] = '\0';
148 * Kernel protocol v5 packet for handling indirect and direct
149 * mount missing and expire requests
151 case autofs_ptype_missing_indirect:
152 case autofs_ptype_expire_indirect:
153 case autofs_ptype_missing_direct:
154 case autofs_ptype_expire_direct:
156 struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
158 pktsz = sizeof(*packet);
160 packet->wait_queue_token = wq->wait_queue_token;
161 packet->len = wq->name.len;
162 memcpy(packet->name, wq->name.name, wq->name.len);
163 packet->name[wq->name.len] = '\0';
164 packet->dev = wq->dev;
165 packet->ino = wq->ino;
166 packet->uid = wq->uid;
167 packet->gid = wq->gid;
168 packet->pid = wq->pid;
169 packet->tgid = wq->tgid;
173 printk("autofs4_notify_daemon: bad type %d!\n", type);
174 mutex_unlock(&sbi->wq_mutex);
181 mutex_unlock(&sbi->wq_mutex);
183 if (autofs4_write(sbi, pipe, &pkt, pktsz))
184 autofs4_catatonic_mode(sbi);
188 static int autofs4_getpath(struct autofs_sb_info *sbi,
189 struct dentry *dentry, char **name)
191 struct dentry *root = sbi->sb->s_root;
202 seq = read_seqbegin(&rename_lock);
204 spin_lock(&sbi->fs_lock);
205 for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
206 len += tmp->d_name.len + 1;
208 if (!len || --len > NAME_MAX) {
209 spin_unlock(&sbi->fs_lock);
211 if (read_seqretry(&rename_lock, seq))
217 p = buf + len - dentry->d_name.len;
218 strncpy(p, dentry->d_name.name, dentry->d_name.len);
220 for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
222 p -= tmp->d_name.len;
223 strncpy(p, tmp->d_name.name, tmp->d_name.len);
225 spin_unlock(&sbi->fs_lock);
227 if (read_seqretry(&rename_lock, seq))
233 static struct autofs_wait_queue *
234 autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr)
236 struct autofs_wait_queue *wq;
238 for (wq = sbi->queues; wq; wq = wq->next) {
239 if (wq->name.hash == qstr->hash &&
240 wq->name.len == qstr->len &&
242 !memcmp(wq->name.name, qstr->name, qstr->len))
249 * Check if we have a valid request.
251 * 1 if the request should continue.
252 * In this case we can return an autofs_wait_queue entry if one is
253 * found or NULL to idicate a new wait needs to be created.
254 * 0 or a negative errno if the request shouldn't continue.
256 static int validate_request(struct autofs_wait_queue **wait,
257 struct autofs_sb_info *sbi,
259 struct dentry*dentry, enum autofs_notify notify)
261 struct autofs_wait_queue *wq;
262 struct autofs_info *ino;
267 /* Wait in progress, continue; */
268 wq = autofs4_find_wait(sbi, qstr);
276 /* If we don't yet have any info this is a new request */
277 ino = autofs4_dentry_ino(dentry);
282 * If we've been asked to wait on an existing expire (NFY_NONE)
283 * but there is no wait in the queue ...
285 if (notify == NFY_NONE) {
287 * Either we've betean the pending expire to post it's
288 * wait or it finished while we waited on the mutex.
289 * So we need to wait till either, the wait appears
290 * or the expire finishes.
293 while (ino->flags & AUTOFS_INF_EXPIRING) {
294 mutex_unlock(&sbi->wq_mutex);
295 schedule_timeout_interruptible(HZ/10);
296 if (mutex_lock_interruptible(&sbi->wq_mutex))
302 wq = autofs4_find_wait(sbi, qstr);
310 * Not ideal but the status has already gone. Of the two
311 * cases where we wait on NFY_NONE neither depend on the
312 * return status of the wait.
318 * If we've been asked to trigger a mount and the request
319 * completed while we waited on the mutex ...
321 if (notify == NFY_MOUNT) {
322 struct dentry *new = NULL;
326 * If the dentry was successfully mounted while we slept
327 * on the wait queue mutex we can return success. If it
328 * isn't mounted (doesn't have submounts for the case of
329 * a multi-mount with no mount at it's base) we can
330 * continue on and create a new request.
332 if (!IS_ROOT(dentry)) {
333 if (dentry->d_inode && d_unhashed(dentry)) {
334 struct dentry *parent = dentry->d_parent;
335 new = d_lookup(parent, &dentry->d_name);
340 if (have_submounts(dentry))
351 int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
352 enum autofs_notify notify)
354 struct autofs_wait_queue *wq;
357 int status, ret, type;
359 /* In catatonic mode, we don't wait for nobody */
363 if (!dentry->d_inode) {
365 * A wait for a negative dentry is invalid for certain
366 * cases. A direct or offset mount "always" has its mount
367 * point directory created and so the request dentry must
368 * be positive or the map key doesn't exist. The situation
369 * is very similar for indirect mounts except only dentrys
370 * in the root of the autofs file system may be negative.
372 if (autofs_type_trigger(sbi->type))
374 else if (!IS_ROOT(dentry->d_parent))
378 name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
382 /* If this is a direct mount request create a dummy name */
383 if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
384 qstr.len = sprintf(name, "%p", dentry);
386 qstr.len = autofs4_getpath(sbi, dentry, &name);
393 qstr.hash = full_name_hash(name, qstr.len);
395 if (mutex_lock_interruptible(&sbi->wq_mutex)) {
400 ret = validate_request(&wq, sbi, &qstr, dentry, notify);
403 mutex_unlock(&sbi->wq_mutex);
409 /* Create a new wait queue */
410 wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
413 mutex_unlock(&sbi->wq_mutex);
417 wq->wait_queue_token = autofs4_next_wait_queue;
418 if (++autofs4_next_wait_queue == 0)
419 autofs4_next_wait_queue = 1;
420 wq->next = sbi->queues;
422 init_waitqueue_head(&wq->queue);
423 memcpy(&wq->name, &qstr, sizeof(struct qstr));
424 wq->dev = autofs4_get_dev(sbi);
425 wq->ino = autofs4_get_ino(sbi);
426 wq->uid = current_uid();
427 wq->gid = current_gid();
428 wq->pid = current->pid;
429 wq->tgid = current->tgid;
430 wq->status = -EINTR; /* Status return if interrupted */
432 mutex_unlock(&sbi->wq_mutex);
434 if (sbi->version < 5) {
435 if (notify == NFY_MOUNT)
436 type = autofs_ptype_missing;
438 type = autofs_ptype_expire_multi;
440 if (notify == NFY_MOUNT)
441 type = autofs_type_trigger(sbi->type) ?
442 autofs_ptype_missing_direct :
443 autofs_ptype_missing_indirect;
445 type = autofs_type_trigger(sbi->type) ?
446 autofs_ptype_expire_direct :
447 autofs_ptype_expire_indirect;
450 DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
451 (unsigned long) wq->wait_queue_token, wq->name.len,
452 wq->name.name, notify);
454 /* autofs4_notify_daemon() may block */
455 autofs4_notify_daemon(sbi, wq, type);
458 mutex_unlock(&sbi->wq_mutex);
460 DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
461 (unsigned long) wq->wait_queue_token, wq->name.len,
462 wq->name.name, notify);
466 * wq->name.name is NULL iff the lock is already released
467 * or the mount has been made catatonic.
470 /* Block all but "shutdown" signals while waiting */
472 unsigned long irqflags;
474 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
475 oldset = current->blocked;
476 siginitsetinv(¤t->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
478 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
480 wait_event_interruptible(wq->queue, wq->name.name == NULL);
482 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
483 current->blocked = oldset;
485 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
487 DPRINTK("skipped sleeping");
493 * For direct and offset mounts we need to track the requester's
494 * uid and gid in the dentry info struct. This is so it can be
495 * supplied, on request, by the misc device ioctl interface.
496 * This is needed during daemon resatart when reconnecting
497 * to existing, active, autofs mounts. The uid and gid (and
498 * related string values) may be used for macro substitution
499 * in autofs mount maps.
502 struct autofs_info *ino;
503 struct dentry *de = NULL;
505 /* direct mount or browsable map */
506 ino = autofs4_dentry_ino(dentry);
508 /* If not lookup actual dentry used */
509 de = d_lookup(dentry->d_parent, &dentry->d_name);
511 ino = autofs4_dentry_ino(de);
514 /* Set mount requester */
516 spin_lock(&sbi->fs_lock);
519 spin_unlock(&sbi->fs_lock);
526 /* Are we the last process to need status? */
527 mutex_lock(&sbi->wq_mutex);
530 mutex_unlock(&sbi->wq_mutex);
536 int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
538 struct autofs_wait_queue *wq, **wql;
540 mutex_lock(&sbi->wq_mutex);
541 for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
542 if (wq->wait_queue_token == wait_queue_token)
547 mutex_unlock(&sbi->wq_mutex);
551 *wql = wq->next; /* Unlink from chain */
552 kfree(wq->name.name);
553 wq->name.name = NULL; /* Do not wait on this queue */
555 wake_up_interruptible(&wq->queue);
558 mutex_unlock(&sbi->wq_mutex);