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);
96 * The autofs_v5 packet was misdesigned.
98 * The packets are identical on x86-32 and x86-64, but have different
99 * alignment. Which means that 'sizeof()' will give different results.
100 * Fix it up for the case of running 32-bit user mode on a 64-bit kernel.
102 static noinline size_t autofs_v5_packet_size(struct autofs_sb_info *sbi)
104 size_t pktsz = sizeof(struct autofs_v5_packet);
105 #if defined(CONFIG_X86_64) && defined(CONFIG_COMPAT)
106 if (sbi->compat_daemon > 0)
112 static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
113 struct autofs_wait_queue *wq,
117 struct autofs_packet_hdr hdr;
118 union autofs_packet_union v4_pkt;
119 union autofs_v5_packet_union v5_pkt;
121 struct file *pipe = NULL;
124 DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
125 (unsigned long) wq->wait_queue_token, wq->name.len, wq->name.name, type);
127 memset(&pkt,0,sizeof pkt); /* For security reasons */
129 pkt.hdr.proto_version = sbi->version;
131 mutex_lock(&sbi->wq_mutex);
133 /* Check if we have become catatonic */
134 if (sbi->catatonic) {
135 mutex_unlock(&sbi->wq_mutex);
139 /* Kernel protocol v4 missing and expire packets */
140 case autofs_ptype_missing:
142 struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
146 mp->wait_queue_token = wq->wait_queue_token;
147 mp->len = wq->name.len;
148 memcpy(mp->name, wq->name.name, wq->name.len);
149 mp->name[wq->name.len] = '\0';
152 case autofs_ptype_expire_multi:
154 struct autofs_packet_expire_multi *ep = &pkt.v4_pkt.expire_multi;
158 ep->wait_queue_token = wq->wait_queue_token;
159 ep->len = wq->name.len;
160 memcpy(ep->name, wq->name.name, wq->name.len);
161 ep->name[wq->name.len] = '\0';
165 * Kernel protocol v5 packet for handling indirect and direct
166 * mount missing and expire requests
168 case autofs_ptype_missing_indirect:
169 case autofs_ptype_expire_indirect:
170 case autofs_ptype_missing_direct:
171 case autofs_ptype_expire_direct:
173 struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
175 pktsz = autofs_v5_packet_size(sbi);
176 packet->wait_queue_token = wq->wait_queue_token;
177 packet->len = wq->name.len;
178 memcpy(packet->name, wq->name.name, wq->name.len);
179 packet->name[wq->name.len] = '\0';
180 packet->dev = wq->dev;
181 packet->ino = wq->ino;
182 packet->uid = wq->uid;
183 packet->gid = wq->gid;
184 packet->pid = wq->pid;
185 packet->tgid = wq->tgid;
189 printk("autofs4_notify_daemon: bad type %d!\n", type);
190 mutex_unlock(&sbi->wq_mutex);
197 mutex_unlock(&sbi->wq_mutex);
199 if (autofs4_write(sbi, pipe, &pkt, pktsz))
200 autofs4_catatonic_mode(sbi);
204 static int autofs4_getpath(struct autofs_sb_info *sbi,
205 struct dentry *dentry, char **name)
207 struct dentry *root = sbi->sb->s_root;
218 seq = read_seqbegin(&rename_lock);
220 spin_lock(&sbi->fs_lock);
221 for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
222 len += tmp->d_name.len + 1;
224 if (!len || --len > NAME_MAX) {
225 spin_unlock(&sbi->fs_lock);
227 if (read_seqretry(&rename_lock, seq))
233 p = buf + len - dentry->d_name.len;
234 strncpy(p, dentry->d_name.name, dentry->d_name.len);
236 for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
238 p -= tmp->d_name.len;
239 strncpy(p, tmp->d_name.name, tmp->d_name.len);
241 spin_unlock(&sbi->fs_lock);
243 if (read_seqretry(&rename_lock, seq))
249 static struct autofs_wait_queue *
250 autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr)
252 struct autofs_wait_queue *wq;
254 for (wq = sbi->queues; wq; wq = wq->next) {
255 if (wq->name.hash == qstr->hash &&
256 wq->name.len == qstr->len &&
258 !memcmp(wq->name.name, qstr->name, qstr->len))
265 * Check if we have a valid request.
267 * 1 if the request should continue.
268 * In this case we can return an autofs_wait_queue entry if one is
269 * found or NULL to idicate a new wait needs to be created.
270 * 0 or a negative errno if the request shouldn't continue.
272 static int validate_request(struct autofs_wait_queue **wait,
273 struct autofs_sb_info *sbi,
275 struct dentry*dentry, enum autofs_notify notify)
277 struct autofs_wait_queue *wq;
278 struct autofs_info *ino;
283 /* Wait in progress, continue; */
284 wq = autofs4_find_wait(sbi, qstr);
292 /* If we don't yet have any info this is a new request */
293 ino = autofs4_dentry_ino(dentry);
298 * If we've been asked to wait on an existing expire (NFY_NONE)
299 * but there is no wait in the queue ...
301 if (notify == NFY_NONE) {
303 * Either we've betean the pending expire to post it's
304 * wait or it finished while we waited on the mutex.
305 * So we need to wait till either, the wait appears
306 * or the expire finishes.
309 while (ino->flags & AUTOFS_INF_EXPIRING) {
310 mutex_unlock(&sbi->wq_mutex);
311 schedule_timeout_interruptible(HZ/10);
312 if (mutex_lock_interruptible(&sbi->wq_mutex))
318 wq = autofs4_find_wait(sbi, qstr);
326 * Not ideal but the status has already gone. Of the two
327 * cases where we wait on NFY_NONE neither depend on the
328 * return status of the wait.
334 * If we've been asked to trigger a mount and the request
335 * completed while we waited on the mutex ...
337 if (notify == NFY_MOUNT) {
338 struct dentry *new = NULL;
342 * If the dentry was successfully mounted while we slept
343 * on the wait queue mutex we can return success. If it
344 * isn't mounted (doesn't have submounts for the case of
345 * a multi-mount with no mount at it's base) we can
346 * continue on and create a new request.
348 if (!IS_ROOT(dentry)) {
349 if (dentry->d_inode && d_unhashed(dentry)) {
350 struct dentry *parent = dentry->d_parent;
351 new = d_lookup(parent, &dentry->d_name);
356 if (have_submounts(dentry))
367 int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
368 enum autofs_notify notify)
370 struct autofs_wait_queue *wq;
373 int status, ret, type;
375 /* In catatonic mode, we don't wait for nobody */
379 if (!dentry->d_inode) {
381 * A wait for a negative dentry is invalid for certain
382 * cases. A direct or offset mount "always" has its mount
383 * point directory created and so the request dentry must
384 * be positive or the map key doesn't exist. The situation
385 * is very similar for indirect mounts except only dentrys
386 * in the root of the autofs file system may be negative.
388 if (autofs_type_trigger(sbi->type))
390 else if (!IS_ROOT(dentry->d_parent))
394 name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
398 /* If this is a direct mount request create a dummy name */
399 if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
400 qstr.len = sprintf(name, "%p", dentry);
402 qstr.len = autofs4_getpath(sbi, dentry, &name);
409 qstr.hash = full_name_hash(name, qstr.len);
411 if (mutex_lock_interruptible(&sbi->wq_mutex)) {
416 ret = validate_request(&wq, sbi, &qstr, dentry, notify);
419 mutex_unlock(&sbi->wq_mutex);
425 /* Create a new wait queue */
426 wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
429 mutex_unlock(&sbi->wq_mutex);
433 wq->wait_queue_token = autofs4_next_wait_queue;
434 if (++autofs4_next_wait_queue == 0)
435 autofs4_next_wait_queue = 1;
436 wq->next = sbi->queues;
438 init_waitqueue_head(&wq->queue);
439 memcpy(&wq->name, &qstr, sizeof(struct qstr));
440 wq->dev = autofs4_get_dev(sbi);
441 wq->ino = autofs4_get_ino(sbi);
442 wq->uid = current_uid();
443 wq->gid = current_gid();
444 wq->pid = current->pid;
445 wq->tgid = current->tgid;
446 wq->status = -EINTR; /* Status return if interrupted */
448 mutex_unlock(&sbi->wq_mutex);
450 if (sbi->version < 5) {
451 if (notify == NFY_MOUNT)
452 type = autofs_ptype_missing;
454 type = autofs_ptype_expire_multi;
456 if (notify == NFY_MOUNT)
457 type = autofs_type_trigger(sbi->type) ?
458 autofs_ptype_missing_direct :
459 autofs_ptype_missing_indirect;
461 type = autofs_type_trigger(sbi->type) ?
462 autofs_ptype_expire_direct :
463 autofs_ptype_expire_indirect;
466 DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
467 (unsigned long) wq->wait_queue_token, wq->name.len,
468 wq->name.name, notify);
470 /* autofs4_notify_daemon() may block */
471 autofs4_notify_daemon(sbi, wq, type);
474 mutex_unlock(&sbi->wq_mutex);
476 DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
477 (unsigned long) wq->wait_queue_token, wq->name.len,
478 wq->name.name, notify);
482 * wq->name.name is NULL iff the lock is already released
483 * or the mount has been made catatonic.
486 /* Block all but "shutdown" signals while waiting */
488 unsigned long irqflags;
490 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
491 oldset = current->blocked;
492 siginitsetinv(¤t->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
494 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
496 wait_event_interruptible(wq->queue, wq->name.name == NULL);
498 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
499 current->blocked = oldset;
501 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
503 DPRINTK("skipped sleeping");
509 * For direct and offset mounts we need to track the requester's
510 * uid and gid in the dentry info struct. This is so it can be
511 * supplied, on request, by the misc device ioctl interface.
512 * This is needed during daemon resatart when reconnecting
513 * to existing, active, autofs mounts. The uid and gid (and
514 * related string values) may be used for macro substitution
515 * in autofs mount maps.
518 struct autofs_info *ino;
519 struct dentry *de = NULL;
521 /* direct mount or browsable map */
522 ino = autofs4_dentry_ino(dentry);
524 /* If not lookup actual dentry used */
525 de = d_lookup(dentry->d_parent, &dentry->d_name);
527 ino = autofs4_dentry_ino(de);
530 /* Set mount requester */
532 spin_lock(&sbi->fs_lock);
535 spin_unlock(&sbi->fs_lock);
542 /* Are we the last process to need status? */
543 mutex_lock(&sbi->wq_mutex);
546 mutex_unlock(&sbi->wq_mutex);
552 int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
554 struct autofs_wait_queue *wq, **wql;
556 mutex_lock(&sbi->wq_mutex);
557 for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
558 if (wq->wait_queue_token == wait_queue_token)
563 mutex_unlock(&sbi->wq_mutex);
567 *wql = wq->next; /* Unlink from chain */
568 kfree(wq->name.name);
569 wq->name.name = NULL; /* Do not wait on this queue */
571 wake_up_interruptible(&wq->queue);
574 mutex_unlock(&sbi->wq_mutex);