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 DPRINTK("entering catatonic mode");
35 sbi
->queues
= NULL
; /* Erase all wait queues */
38 wq
->status
= -ENOENT
; /* Magic is gone - report failure */
41 wake_up_interruptible(&wq
->queue
);
45 fput(sbi
->pipe
); /* Close the pipe */
48 shrink_dcache_sb(sbi
->sb
);
51 static int autofs4_write(struct file
*file
, const void *addr
, int bytes
)
53 unsigned long sigpipe
, flags
;
55 const char *data
= (const char *)addr
;
58 /** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/
60 sigpipe
= sigismember(¤t
->pending
.signal
, SIGPIPE
);
62 /* Save pointer to user space and point back to kernel space */
67 (wr
= file
->f_op
->write(file
,data
,bytes
,&file
->f_pos
)) > 0) {
74 /* Keep the currently executing process from receiving a
75 SIGPIPE unless it was already supposed to get one */
76 if (wr
== -EPIPE
&& !sigpipe
) {
77 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
78 sigdelset(¤t
->pending
.signal
, SIGPIPE
);
80 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
86 static void autofs4_notify_daemon(struct autofs_sb_info
*sbi
,
87 struct autofs_wait_queue
*wq
,
90 union autofs_packet_union pkt
;
93 DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
94 wq
->wait_queue_token
, wq
->len
, wq
->name
, type
);
96 memset(&pkt
,0,sizeof pkt
); /* For security reasons */
98 pkt
.hdr
.proto_version
= sbi
->version
;
101 /* Kernel protocol v4 missing and expire packets */
102 case autofs_ptype_missing
:
104 struct autofs_packet_missing
*mp
= &pkt
.missing
;
108 mp
->wait_queue_token
= wq
->wait_queue_token
;
110 memcpy(mp
->name
, wq
->name
, wq
->len
);
111 mp
->name
[wq
->len
] = '\0';
114 case autofs_ptype_expire_multi
:
116 struct autofs_packet_expire_multi
*ep
= &pkt
.expire_multi
;
120 ep
->wait_queue_token
= wq
->wait_queue_token
;
122 memcpy(ep
->name
, wq
->name
, wq
->len
);
123 ep
->name
[wq
->len
] = '\0';
127 * Kernel protocol v5 packet for handling indirect and direct
128 * mount missing and expire requests
130 case autofs_ptype_missing_indirect
:
131 case autofs_ptype_expire_indirect
:
132 case autofs_ptype_missing_direct
:
133 case autofs_ptype_expire_direct
:
135 struct autofs_v5_packet
*packet
= &pkt
.v5_packet
;
137 pktsz
= sizeof(*packet
);
139 packet
->wait_queue_token
= wq
->wait_queue_token
;
140 packet
->len
= wq
->len
;
141 memcpy(packet
->name
, wq
->name
, wq
->len
);
142 packet
->name
[wq
->len
] = '\0';
143 packet
->dev
= wq
->dev
;
144 packet
->ino
= wq
->ino
;
145 packet
->uid
= wq
->uid
;
146 packet
->gid
= wq
->gid
;
147 packet
->pid
= wq
->pid
;
148 packet
->tgid
= wq
->tgid
;
152 printk("autofs4_notify_daemon: bad type %d!\n", type
);
156 if (autofs4_write(sbi
->pipe
, &pkt
, pktsz
))
157 autofs4_catatonic_mode(sbi
);
160 static int autofs4_getpath(struct autofs_sb_info
*sbi
,
161 struct dentry
*dentry
, char **name
)
163 struct dentry
*root
= sbi
->sb
->s_root
;
169 spin_lock(&dcache_lock
);
170 for (tmp
= dentry
; tmp
!= root
; tmp
= tmp
->d_parent
)
171 len
+= tmp
->d_name
.len
+ 1;
173 if (--len
> NAME_MAX
) {
174 spin_unlock(&dcache_lock
);
179 p
= buf
+ len
- dentry
->d_name
.len
;
180 strncpy(p
, dentry
->d_name
.name
, dentry
->d_name
.len
);
182 for (tmp
= dentry
->d_parent
; tmp
!= root
; tmp
= tmp
->d_parent
) {
184 p
-= tmp
->d_name
.len
;
185 strncpy(p
, tmp
->d_name
.name
, tmp
->d_name
.len
);
187 spin_unlock(&dcache_lock
);
192 int autofs4_wait(struct autofs_sb_info
*sbi
, struct dentry
*dentry
,
193 enum autofs_notify notify
)
195 struct autofs_wait_queue
*wq
;
197 unsigned int len
= 0;
198 unsigned int hash
= 0;
201 /* In catatonic mode, we don't wait for nobody */
205 name
= kmalloc(NAME_MAX
+ 1, GFP_KERNEL
);
209 /* If this is a direct mount request create a dummy name */
210 if (IS_ROOT(dentry
) && (sbi
->type
& AUTOFS_TYPE_DIRECT
))
211 len
= sprintf(name
, "%p", dentry
);
213 len
= autofs4_getpath(sbi
, dentry
, &name
);
219 hash
= full_name_hash(name
, len
);
221 if (mutex_lock_interruptible(&sbi
->wq_mutex
)) {
226 for (wq
= sbi
->queues
; wq
; wq
= wq
->next
) {
227 if (wq
->hash
== dentry
->d_name
.hash
&&
229 wq
->name
&& !memcmp(wq
->name
, name
, len
))
234 /* Can't wait for an expire if there's no mount */
235 if (notify
== NFY_NONE
&& !d_mountpoint(dentry
)) {
237 mutex_unlock(&sbi
->wq_mutex
);
241 /* Create a new wait queue */
242 wq
= kmalloc(sizeof(struct autofs_wait_queue
),GFP_KERNEL
);
245 mutex_unlock(&sbi
->wq_mutex
);
249 wq
->wait_queue_token
= autofs4_next_wait_queue
;
250 if (++autofs4_next_wait_queue
== 0)
251 autofs4_next_wait_queue
= 1;
252 wq
->next
= sbi
->queues
;
254 init_waitqueue_head(&wq
->queue
);
258 wq
->dev
= autofs4_get_dev(sbi
);
259 wq
->ino
= autofs4_get_ino(sbi
);
260 wq
->uid
= current
->uid
;
261 wq
->gid
= current
->gid
;
262 wq
->pid
= current
->pid
;
263 wq
->tgid
= current
->tgid
;
264 wq
->status
= -EINTR
; /* Status return if interrupted */
265 atomic_set(&wq
->wait_ctr
, 2);
266 atomic_set(&wq
->notify
, 1);
267 mutex_unlock(&sbi
->wq_mutex
);
269 atomic_inc(&wq
->wait_ctr
);
270 mutex_unlock(&sbi
->wq_mutex
);
272 DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
273 (unsigned long) wq
->wait_queue_token
, wq
->len
, wq
->name
, notify
);
276 if (notify
!= NFY_NONE
&& atomic_read(&wq
->notify
)) {
279 atomic_dec(&wq
->notify
);
281 if (sbi
->version
< 5) {
282 if (notify
== NFY_MOUNT
)
283 type
= autofs_ptype_missing
;
285 type
= autofs_ptype_expire_multi
;
287 if (notify
== NFY_MOUNT
)
288 type
= (sbi
->type
& AUTOFS_TYPE_DIRECT
) ?
289 autofs_ptype_missing_direct
:
290 autofs_ptype_missing_indirect
;
292 type
= (sbi
->type
& AUTOFS_TYPE_DIRECT
) ?
293 autofs_ptype_expire_direct
:
294 autofs_ptype_expire_indirect
;
297 DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
298 (unsigned long) wq
->wait_queue_token
, wq
->len
, wq
->name
, notify
);
300 /* autofs4_notify_daemon() may block */
301 autofs4_notify_daemon(sbi
, wq
, type
);
304 /* wq->name is NULL if and only if the lock is already released */
306 if (sbi
->catatonic
) {
307 /* We might have slept, so check again for catatonic mode */
308 wq
->status
= -ENOENT
;
314 /* Block all but "shutdown" signals while waiting */
316 unsigned long irqflags
;
318 spin_lock_irqsave(¤t
->sighand
->siglock
, irqflags
);
319 oldset
= current
->blocked
;
320 siginitsetinv(¤t
->blocked
, SHUTDOWN_SIGS
& ~oldset
.sig
[0]);
322 spin_unlock_irqrestore(¤t
->sighand
->siglock
, irqflags
);
324 wait_event_interruptible(wq
->queue
, wq
->name
== NULL
);
326 spin_lock_irqsave(¤t
->sighand
->siglock
, irqflags
);
327 current
->blocked
= oldset
;
329 spin_unlock_irqrestore(¤t
->sighand
->siglock
, irqflags
);
331 DPRINTK("skipped sleeping");
336 /* Are we the last process to need status? */
337 if (atomic_dec_and_test(&wq
->wait_ctr
))
344 int autofs4_wait_release(struct autofs_sb_info
*sbi
, autofs_wqt_t wait_queue_token
, int status
)
346 struct autofs_wait_queue
*wq
, **wql
;
348 mutex_lock(&sbi
->wq_mutex
);
349 for (wql
= &sbi
->queues
; (wq
= *wql
) != 0 ; wql
= &wq
->next
) {
350 if (wq
->wait_queue_token
== wait_queue_token
)
355 mutex_unlock(&sbi
->wq_mutex
);
359 *wql
= wq
->next
; /* Unlink from chain */
360 mutex_unlock(&sbi
->wq_mutex
);
362 wq
->name
= NULL
; /* Do not wait on this queue */
366 if (atomic_dec_and_test(&wq
->wait_ctr
)) /* Is anyone still waiting for this guy? */
369 wake_up_interruptible(&wq
->queue
);