==> Regarding [PATCH 1/3] autofs4 - expiring filesystem from under process;
[EMAIL PROTECTED] adds:
raven> autofs4-2.6.12-rc1-mm4-wait-order.patch
raven> It's possible for an event wait request to arive before the event
raven> requestor. If this happens the daemon never gets notified and autofs
raven> hangs.
I'm not sure I understand your problem description. Could you please
elaborate on the set of circumstances that lead to this?
Could also please explain how the following is handled:
expire process runs and issues AUTOFS_EXPIRE_MULTI, which sets
AUTOFS_INF_EXPIRING in flags. While the expire is in progress, another
process access the directory in question, causing a call to
try_to_fill_dentry. try_to_fill_dentry sees the AUTOFS_INF_EXPIRING flag
is set, and so calls autofs4_wait with notify set to NFY_NONE. However,
when we take the wq sem, we find that the expire has finished, and thus
create a new wq entry. Because NFY_NONE is set, we don't tell the daemon.
So how will this process ever get woken up?
Thanks!
Jeff
raven> Signed-off-by: Ian Kent <[EMAIL PROTECTED]>
raven> --- linux-2.6.12-rc1-mm4/fs/autofs4/waitq.c.wait-order 2005-04-03
12:30:14.000000000 +0800
raven> +++ linux-2.6.12-rc1-mm4/fs/autofs4/waitq.c 2005-04-03
12:31:57.000000000 +0800
raven> @@ -210,17 +210,8 @@ int autofs4_wait(struct autofs_sb_info *
wq-> len = len;
wq-> status = -EINTR; /* Status return if interrupted */
raven> atomic_set(&wq->wait_ctr, 2);
raven> + atomic_set(&wq->notified, 1);
raven> up(&sbi->wq_sem);
raven> -
raven> - DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d",
raven> - (unsigned long) wq->wait_queue_token, wq->len,
wq->name, notify);
raven> - /* autofs4_notify_daemon() may block */
raven> - if (notify != NFY_NONE) {
raven> - autofs4_notify_daemon(sbi,wq,
raven> - notify == NFY_MOUNT ?
raven> - autofs_ptype_missing :
raven> -
autofs_ptype_expire_multi);
raven> - }
raven> } else {
raven> atomic_inc(&wq->wait_ctr);
raven> up(&sbi->wq_sem);
raven> @@ -229,6 +220,17 @@ int autofs4_wait(struct autofs_sb_info *
raven> (unsigned long) wq->wait_queue_token, wq->len,
wq->name, notify);
raven> }
raven> + if (notify != NFY_NONE && atomic_dec_and_test(&wq->notified)) {
raven> + int type = (notify == NFY_MOUNT ?
raven> + autofs_ptype_missing :
autofs_ptype_expire_multi);
raven> +
raven> + DPRINTK(("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
raven> + (unsigned long) wq->wait_queue_token, wq->len,
wq->name, notify));
raven> +
raven> + /* autofs4_notify_daemon() may block */
raven> + autofs4_notify_daemon(sbi, wq, type);
raven> + }
raven> +
raven> /* wq->name is NULL if and only if the lock is already released
*/
raven> if ( sbi->catatonic ) {
raven> --- linux-2.6.12-rc1-mm4/fs/autofs4/autofs_i.h.wait-order
2005-04-03 12:30:24.000000000 +0800
raven> +++ linux-2.6.12-rc1-mm4/fs/autofs4/autofs_i.h 2005-04-03
12:30:46.000000000 +0800
raven> @@ -84,6 +84,7 @@ struct autofs_wait_queue {
raven> char *name;
raven> /* This is for status reporting upon return */
raven> int status;
raven> + atomic_t notified;
raven> atomic_t wait_ctr;
raven> };
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