[PATCH] autofs4: wait order fix
It's possible for an event wait request to arive before the event
requestor. If this happens the daemon never gets notified and autofs
hangs.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index 1ab24a6..5a40d36 100644
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -210,17 +210,8 @@
wq->len = len;
wq->status = -EINTR; /* Status return if interrupted */
atomic_set(&wq->wait_ctr, 2);
+ atomic_set(&wq->notified, 1);
up(&sbi->wq_sem);
-
- DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d",
- (unsigned long) wq->wait_queue_token, wq->len, wq->name, notify);
- /* autofs4_notify_daemon() may block */
- if (notify != NFY_NONE) {
- autofs4_notify_daemon(sbi,wq,
- notify == NFY_MOUNT ?
- autofs_ptype_missing :
- autofs_ptype_expire_multi);
- }
} else {
atomic_inc(&wq->wait_ctr);
up(&sbi->wq_sem);
@@ -229,6 +220,17 @@
(unsigned long) wq->wait_queue_token, wq->len, wq->name, notify);
}
+ if (notify != NFY_NONE && atomic_dec_and_test(&wq->notified)) {
+ int type = (notify == NFY_MOUNT ?
+ autofs_ptype_missing : autofs_ptype_expire_multi);
+
+ DPRINTK(("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
+ (unsigned long) wq->wait_queue_token, wq->len, wq->name, notify));
+
+ /* autofs4_notify_daemon() may block */
+ autofs4_notify_daemon(sbi, wq, type);
+ }
+
/* wq->name is NULL if and only if the lock is already released */
if ( sbi->catatonic ) {