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 file *file, const void *addr, int bytes)
61 unsigned long sigpipe, flags;
63 const char *data = (const char *)addr;
66 /** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/
68 sigpipe = sigismember(¤t->pending.signal, SIGPIPE);
70 /* Save pointer to user space and point back to kernel space */
75 (wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) {
82 /* Keep the currently executing process from receiving a
83 SIGPIPE unless it was already supposed to get one */
84 if (wr == -EPIPE && !sigpipe) {
85 spin_lock_irqsave(¤t->sighand->siglock, flags);
86 sigdelset(¤t->pending.signal, SIGPIPE);
88 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
95 * The autofs_v5 packet was misdesigned.
97 * The packets are identical on x86-32 and x86-64, but have different
98 * alignment. Which means that 'sizeof()' will give different results.
99 * Fix it up for the case of running 32-bit user mode on a 64-bit kernel.
101 static noinline size_t autofs_v5_packet_size(struct autofs_sb_info *sbi)
103 size_t pktsz = sizeof(struct autofs_v5_packet);
104 #if defined(CONFIG_X86_64) && defined(CONFIG_COMPAT)
105 if (sbi->compat_daemon > 0)
111 static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
112 struct autofs_wait_queue *wq,
116 struct autofs_packet_hdr hdr;
117 union autofs_packet_union v4_pkt;
118 union autofs_v5_packet_union v5_pkt;
120 struct file *pipe = NULL;
123 DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
124 wq->wait_queue_token, wq->name.len, wq->name.name, type);
126 memset(&pkt,0,sizeof pkt); /* For security reasons */
128 pkt.hdr.proto_version = sbi->version;
131 /* Kernel protocol v4 missing and expire packets */
132 case autofs_ptype_missing:
134 struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
138 mp->wait_queue_token = wq->wait_queue_token;
139 mp->len = wq->name.len;
140 memcpy(mp->name, wq->name.name, wq->name.len);
141 mp->name[wq->name.len] = '\0';
144 case autofs_ptype_expire_multi:
146 struct autofs_packet_expire_multi *ep = &pkt.v4_pkt.expire_multi;
150 ep->wait_queue_token = wq->wait_queue_token;
151 ep->len = wq->name.len;
152 memcpy(ep->name, wq->name.name, wq->name.len);
153 ep->name[wq->name.len] = '\0';
157 * Kernel protocol v5 packet for handling indirect and direct
158 * mount missing and expire requests
160 case autofs_ptype_missing_indirect:
161 case autofs_ptype_expire_indirect:
162 case autofs_ptype_missing_direct:
163 case autofs_ptype_expire_direct:
165 struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
167 pktsz = autofs_v5_packet_size(sbi);
168 packet->wait_queue_token = wq->wait_queue_token;
169 packet->len = wq->name.len;
170 memcpy(packet->name, wq->name.name, wq->name.len);
171 packet->name[wq->name.len] = '\0';
172 packet->dev = wq->dev;
173 packet->ino = wq->ino;
174 packet->uid = wq->uid;
175 packet->gid = wq->gid;
176 packet->pid = wq->pid;
177 packet->tgid = wq->tgid;
181 printk("autofs4_notify_daemon: bad type %d!\n", type);
185 /* Check if we have become catatonic */
186 mutex_lock(&sbi->wq_mutex);
187 if (!sbi->catatonic) {
191 mutex_unlock(&sbi->wq_mutex);
194 if (autofs4_write(pipe, &pkt, pktsz))
195 autofs4_catatonic_mode(sbi);
200 static int autofs4_getpath(struct autofs_sb_info *sbi,
201 struct dentry *dentry, char **name)
203 struct dentry *root = sbi->sb->s_root;
214 seq = read_seqbegin(&rename_lock);
216 spin_lock(&sbi->fs_lock);
217 for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
218 len += tmp->d_name.len + 1;
220 if (!len || --len > NAME_MAX) {
221 spin_unlock(&sbi->fs_lock);
223 if (read_seqretry(&rename_lock, seq))
229 p = buf + len - dentry->d_name.len;
230 strncpy(p, dentry->d_name.name, dentry->d_name.len);
232 for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
234 p -= tmp->d_name.len;
235 strncpy(p, tmp->d_name.name, tmp->d_name.len);
237 spin_unlock(&sbi->fs_lock);
239 if (read_seqretry(&rename_lock, seq))
245 static struct autofs_wait_queue *
246 autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr)
248 struct autofs_wait_queue *wq;
250 for (wq = sbi->queues; wq; wq = wq->next) {
251 if (wq->name.hash == qstr->hash &&
252 wq->name.len == qstr->len &&
254 !memcmp(wq->name.name, qstr->name, qstr->len))
261 * Check if we have a valid request.
263 * 1 if the request should continue.
264 * In this case we can return an autofs_wait_queue entry if one is
265 * found or NULL to idicate a new wait needs to be created.
266 * 0 or a negative errno if the request shouldn't continue.
268 static int validate_request(struct autofs_wait_queue **wait,
269 struct autofs_sb_info *sbi,
271 struct dentry*dentry, enum autofs_notify notify)
273 struct autofs_wait_queue *wq;
274 struct autofs_info *ino;
276 /* Wait in progress, continue; */
277 wq = autofs4_find_wait(sbi, qstr);
285 /* If we don't yet have any info this is a new request */
286 ino = autofs4_dentry_ino(dentry);
291 * If we've been asked to wait on an existing expire (NFY_NONE)
292 * but there is no wait in the queue ...
294 if (notify == NFY_NONE) {
296 * Either we've betean the pending expire to post it's
297 * wait or it finished while we waited on the mutex.
298 * So we need to wait till either, the wait appears
299 * or the expire finishes.
302 while (ino->flags & AUTOFS_INF_EXPIRING) {
303 mutex_unlock(&sbi->wq_mutex);
304 schedule_timeout_interruptible(HZ/10);
305 if (mutex_lock_interruptible(&sbi->wq_mutex))
308 wq = autofs4_find_wait(sbi, qstr);
316 * Not ideal but the status has already gone. Of the two
317 * cases where we wait on NFY_NONE neither depend on the
318 * return status of the wait.
324 * If we've been asked to trigger a mount and the request
325 * completed while we waited on the mutex ...
327 if (notify == NFY_MOUNT) {
328 struct dentry *new = NULL;
332 * If the dentry was successfully mounted while we slept
333 * on the wait queue mutex we can return success. If it
334 * isn't mounted (doesn't have submounts for the case of
335 * a multi-mount with no mount at it's base) we can
336 * continue on and create a new request.
338 if (!IS_ROOT(dentry)) {
339 if (dentry->d_inode && d_unhashed(dentry)) {
340 struct dentry *parent = dentry->d_parent;
341 new = d_lookup(parent, &dentry->d_name);
346 if (have_submounts(dentry))
357 int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
358 enum autofs_notify notify)
360 struct autofs_wait_queue *wq;
363 int status, ret, type;
365 /* In catatonic mode, we don't wait for nobody */
369 if (!dentry->d_inode) {
371 * A wait for a negative dentry is invalid for certain
372 * cases. A direct or offset mount "always" has its mount
373 * point directory created and so the request dentry must
374 * be positive or the map key doesn't exist. The situation
375 * is very similar for indirect mounts except only dentrys
376 * in the root of the autofs file system may be negative.
378 if (autofs_type_trigger(sbi->type))
380 else if (!IS_ROOT(dentry->d_parent))
384 name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
388 /* If this is a direct mount request create a dummy name */
389 if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
390 qstr.len = sprintf(name, "%p", dentry);
392 qstr.len = autofs4_getpath(sbi, dentry, &name);
399 qstr.hash = full_name_hash(name, qstr.len);
401 if (mutex_lock_interruptible(&sbi->wq_mutex)) {
406 ret = validate_request(&wq, sbi, &qstr, dentry, notify);
409 mutex_unlock(&sbi->wq_mutex);
415 /* Create a new wait queue */
416 wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
419 mutex_unlock(&sbi->wq_mutex);
423 wq->wait_queue_token = autofs4_next_wait_queue;
424 if (++autofs4_next_wait_queue == 0)
425 autofs4_next_wait_queue = 1;
426 wq->next = sbi->queues;
428 init_waitqueue_head(&wq->queue);
429 memcpy(&wq->name, &qstr, sizeof(struct qstr));
430 wq->dev = autofs4_get_dev(sbi);
431 wq->ino = autofs4_get_ino(sbi);
432 wq->uid = current_uid();
433 wq->gid = current_gid();
434 wq->pid = current->pid;
435 wq->tgid = current->tgid;
436 wq->status = -EINTR; /* Status return if interrupted */
438 mutex_unlock(&sbi->wq_mutex);
440 if (sbi->version < 5) {
441 if (notify == NFY_MOUNT)
442 type = autofs_ptype_missing;
444 type = autofs_ptype_expire_multi;
446 if (notify == NFY_MOUNT)
447 type = autofs_type_trigger(sbi->type) ?
448 autofs_ptype_missing_direct :
449 autofs_ptype_missing_indirect;
451 type = autofs_type_trigger(sbi->type) ?
452 autofs_ptype_expire_direct :
453 autofs_ptype_expire_indirect;
456 DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
457 (unsigned long) wq->wait_queue_token, wq->name.len,
458 wq->name.name, notify);
460 /* autofs4_notify_daemon() may block */
461 autofs4_notify_daemon(sbi, wq, type);
464 mutex_unlock(&sbi->wq_mutex);
466 DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
467 (unsigned long) wq->wait_queue_token, wq->name.len,
468 wq->name.name, notify);
472 * wq->name.name is NULL iff the lock is already released
473 * or the mount has been made catatonic.
476 /* Block all but "shutdown" signals while waiting */
478 unsigned long irqflags;
480 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
481 oldset = current->blocked;
482 siginitsetinv(¤t->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
484 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
486 wait_event_interruptible(wq->queue, wq->name.name == NULL);
488 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
489 current->blocked = oldset;
491 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
493 DPRINTK("skipped sleeping");
499 * For direct and offset mounts we need to track the requester's
500 * uid and gid in the dentry info struct. This is so it can be
501 * supplied, on request, by the misc device ioctl interface.
502 * This is needed during daemon resatart when reconnecting
503 * to existing, active, autofs mounts. The uid and gid (and
504 * related string values) may be used for macro substitution
505 * in autofs mount maps.
508 struct autofs_info *ino;
509 struct dentry *de = NULL;
511 /* direct mount or browsable map */
512 ino = autofs4_dentry_ino(dentry);
514 /* If not lookup actual dentry used */
515 de = d_lookup(dentry->d_parent, &dentry->d_name);
517 ino = autofs4_dentry_ino(de);
520 /* Set mount requester */
522 spin_lock(&sbi->fs_lock);
525 spin_unlock(&sbi->fs_lock);
532 /* Are we the last process to need status? */
533 mutex_lock(&sbi->wq_mutex);
536 mutex_unlock(&sbi->wq_mutex);
542 int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
544 struct autofs_wait_queue *wq, **wql;
546 mutex_lock(&sbi->wq_mutex);
547 for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
548 if (wq->wait_queue_token == wait_queue_token)
553 mutex_unlock(&sbi->wq_mutex);
557 *wql = wq->next; /* Unlink from chain */
558 kfree(wq->name.name);
559 wq->name.name = NULL; /* Do not wait on this queue */
561 wake_up_interruptible(&wq->queue);
564 mutex_unlock(&sbi->wq_mutex);