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);
94 static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
95 struct autofs_wait_queue *wq,
99 struct autofs_packet_hdr hdr;
100 union autofs_packet_union v4_pkt;
101 union autofs_v5_packet_union v5_pkt;
103 struct file *pipe = NULL;
106 DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
107 (unsigned long) wq->wait_queue_token, wq->name.len, wq->name.name, type);
109 memset(&pkt,0,sizeof pkt); /* For security reasons */
111 pkt.hdr.proto_version = sbi->version;
113 mutex_lock(&sbi->wq_mutex);
115 /* Check if we have become catatonic */
116 if (sbi->catatonic) {
117 mutex_unlock(&sbi->wq_mutex);
121 /* Kernel protocol v4 missing and expire packets */
122 case autofs_ptype_missing:
124 struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
128 mp->wait_queue_token = wq->wait_queue_token;
129 mp->len = wq->name.len;
130 memcpy(mp->name, wq->name.name, wq->name.len);
131 mp->name[wq->name.len] = '\0';
134 case autofs_ptype_expire_multi:
136 struct autofs_packet_expire_multi *ep = &pkt.v4_pkt.expire_multi;
140 ep->wait_queue_token = wq->wait_queue_token;
141 ep->len = wq->name.len;
142 memcpy(ep->name, wq->name.name, wq->name.len);
143 ep->name[wq->name.len] = '\0';
147 * Kernel protocol v5 packet for handling indirect and direct
148 * mount missing and expire requests
150 case autofs_ptype_missing_indirect:
151 case autofs_ptype_expire_indirect:
152 case autofs_ptype_missing_direct:
153 case autofs_ptype_expire_direct:
155 struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
157 pktsz = sizeof(*packet);
159 packet->wait_queue_token = wq->wait_queue_token;
160 packet->len = wq->name.len;
161 memcpy(packet->name, wq->name.name, wq->name.len);
162 packet->name[wq->name.len] = '\0';
163 packet->dev = wq->dev;
164 packet->ino = wq->ino;
165 packet->uid = wq->uid;
166 packet->gid = wq->gid;
167 packet->pid = wq->pid;
168 packet->tgid = wq->tgid;
172 printk("autofs4_notify_daemon: bad type %d!\n", type);
173 mutex_unlock(&sbi->wq_mutex);
177 pipe = get_file(sbi->pipe);
179 mutex_unlock(&sbi->wq_mutex);
181 if (autofs4_write(pipe, &pkt, pktsz))
182 autofs4_catatonic_mode(sbi);
186 static int autofs4_getpath(struct autofs_sb_info *sbi,
187 struct dentry *dentry, char **name)
189 struct dentry *root = sbi->sb->s_root;
200 seq = read_seqbegin(&rename_lock);
202 spin_lock(&sbi->fs_lock);
203 for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
204 len += tmp->d_name.len + 1;
206 if (!len || --len > NAME_MAX) {
207 spin_unlock(&sbi->fs_lock);
209 if (read_seqretry(&rename_lock, seq))
215 p = buf + len - dentry->d_name.len;
216 strncpy(p, dentry->d_name.name, dentry->d_name.len);
218 for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
220 p -= tmp->d_name.len;
221 strncpy(p, tmp->d_name.name, tmp->d_name.len);
223 spin_unlock(&sbi->fs_lock);
225 if (read_seqretry(&rename_lock, seq))
231 static struct autofs_wait_queue *
232 autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr)
234 struct autofs_wait_queue *wq;
236 for (wq = sbi->queues; wq; wq = wq->next) {
237 if (wq->name.hash == qstr->hash &&
238 wq->name.len == qstr->len &&
240 !memcmp(wq->name.name, qstr->name, qstr->len))
247 * Check if we have a valid request.
249 * 1 if the request should continue.
250 * In this case we can return an autofs_wait_queue entry if one is
251 * found or NULL to idicate a new wait needs to be created.
252 * 0 or a negative errno if the request shouldn't continue.
254 static int validate_request(struct autofs_wait_queue **wait,
255 struct autofs_sb_info *sbi,
257 struct dentry*dentry, enum autofs_notify notify)
259 struct autofs_wait_queue *wq;
260 struct autofs_info *ino;
262 /* Wait in progress, continue; */
263 wq = autofs4_find_wait(sbi, qstr);
271 /* If we don't yet have any info this is a new request */
272 ino = autofs4_dentry_ino(dentry);
277 * If we've been asked to wait on an existing expire (NFY_NONE)
278 * but there is no wait in the queue ...
280 if (notify == NFY_NONE) {
282 * Either we've betean the pending expire to post it's
283 * wait or it finished while we waited on the mutex.
284 * So we need to wait till either, the wait appears
285 * or the expire finishes.
288 while (ino->flags & AUTOFS_INF_EXPIRING) {
289 mutex_unlock(&sbi->wq_mutex);
290 schedule_timeout_interruptible(HZ/10);
291 if (mutex_lock_interruptible(&sbi->wq_mutex))
294 wq = autofs4_find_wait(sbi, qstr);
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.
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;
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 (dentry->d_inode && d_unhashed(dentry)) {
326 struct dentry *parent = dentry->d_parent;
327 new = d_lookup(parent, &dentry->d_name);
332 if (have_submounts(dentry))
343 int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
344 enum autofs_notify notify)
346 struct autofs_wait_queue *wq;
349 int status, ret, type;
351 /* In catatonic mode, we don't wait for nobody */
355 if (!dentry->d_inode) {
357 * A wait for a negative dentry is invalid for certain
358 * cases. A direct or offset mount "always" has its mount
359 * point directory created and so the request dentry must
360 * be positive or the map key doesn't exist. The situation
361 * is very similar for indirect mounts except only dentrys
362 * in the root of the autofs file system may be negative.
364 if (autofs_type_trigger(sbi->type))
366 else if (!IS_ROOT(dentry->d_parent))
370 name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
374 /* If this is a direct mount request create a dummy name */
375 if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
376 qstr.len = sprintf(name, "%p", dentry);
378 qstr.len = autofs4_getpath(sbi, dentry, &name);
385 qstr.hash = full_name_hash(name, qstr.len);
387 if (mutex_lock_interruptible(&sbi->wq_mutex)) {
392 ret = validate_request(&wq, sbi, &qstr, dentry, notify);
395 mutex_unlock(&sbi->wq_mutex);
401 /* Create a new wait queue */
402 wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
405 mutex_unlock(&sbi->wq_mutex);
409 wq->wait_queue_token = autofs4_next_wait_queue;
410 if (++autofs4_next_wait_queue == 0)
411 autofs4_next_wait_queue = 1;
412 wq->next = sbi->queues;
414 init_waitqueue_head(&wq->queue);
415 memcpy(&wq->name, &qstr, sizeof(struct qstr));
416 wq->dev = autofs4_get_dev(sbi);
417 wq->ino = autofs4_get_ino(sbi);
418 wq->uid = current_uid();
419 wq->gid = current_gid();
420 wq->pid = current->pid;
421 wq->tgid = current->tgid;
422 wq->status = -EINTR; /* Status return if interrupted */
424 mutex_unlock(&sbi->wq_mutex);
426 if (sbi->version < 5) {
427 if (notify == NFY_MOUNT)
428 type = autofs_ptype_missing;
430 type = autofs_ptype_expire_multi;
432 if (notify == NFY_MOUNT)
433 type = autofs_type_trigger(sbi->type) ?
434 autofs_ptype_missing_direct :
435 autofs_ptype_missing_indirect;
437 type = autofs_type_trigger(sbi->type) ?
438 autofs_ptype_expire_direct :
439 autofs_ptype_expire_indirect;
442 DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
443 (unsigned long) wq->wait_queue_token, wq->name.len,
444 wq->name.name, notify);
446 /* autofs4_notify_daemon() may block */
447 autofs4_notify_daemon(sbi, wq, type);
450 mutex_unlock(&sbi->wq_mutex);
452 DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
453 (unsigned long) wq->wait_queue_token, wq->name.len,
454 wq->name.name, notify);
458 * wq->name.name is NULL iff the lock is already released
459 * or the mount has been made catatonic.
462 /* Block all but "shutdown" signals while waiting */
464 unsigned long irqflags;
466 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
467 oldset = current->blocked;
468 siginitsetinv(¤t->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
470 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
472 wait_event_interruptible(wq->queue, wq->name.name == NULL);
474 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
475 current->blocked = oldset;
477 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
479 DPRINTK("skipped sleeping");
485 * For direct and offset mounts we need to track the requester's
486 * uid and gid in the dentry info struct. This is so it can be
487 * supplied, on request, by the misc device ioctl interface.
488 * This is needed during daemon resatart when reconnecting
489 * to existing, active, autofs mounts. The uid and gid (and
490 * related string values) may be used for macro substitution
491 * in autofs mount maps.
494 struct autofs_info *ino;
495 struct dentry *de = NULL;
497 /* direct mount or browsable map */
498 ino = autofs4_dentry_ino(dentry);
500 /* If not lookup actual dentry used */
501 de = d_lookup(dentry->d_parent, &dentry->d_name);
503 ino = autofs4_dentry_ino(de);
506 /* Set mount requester */
508 spin_lock(&sbi->fs_lock);
511 spin_unlock(&sbi->fs_lock);
518 /* Are we the last process to need status? */
519 mutex_lock(&sbi->wq_mutex);
522 mutex_unlock(&sbi->wq_mutex);
528 int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
530 struct autofs_wait_queue *wq, **wql;
532 mutex_lock(&sbi->wq_mutex);
533 for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
534 if (wq->wait_queue_token == wait_queue_token)
539 mutex_unlock(&sbi->wq_mutex);
543 *wql = wq->next; /* Unlink from chain */
544 kfree(wq->name.name);
545 wq->name.name = NULL; /* Do not wait on this queue */
547 wake_up_interruptible(&wq->queue);
550 mutex_unlock(&sbi->wq_mutex);