autofs-5.0.4 - improve manual umount recovery

From: Ian Kent <raven@themaw.net>

The check for manually umounted mounts in the expire of direct mounts is

racy and the check itself is inadequate in that it can incorrectly clear

the descriptor of an active mount. Also, we do a similar test following

the expire which is a waste since we can catch this on the next expire.

So these two tests have been combined and the check done only prior to

the expire. In the indirect expire we don't have a check at all so we

add one.

---

 CHANGELOG         |    1 +

 daemon/direct.c   |   28 ++++++++++------------------

 daemon/indirect.c |   47 ++++++++++++++++++++++++++++++++++++++++++++++-

 3 files changed, 57 insertions(+), 19 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG

index 5e01812..89aaa99 100644

--- a/CHANGELOG

+++ b/CHANGELOG

@@ -45,6 +45,7 @@

 - fix kernel includes.

 - dont umount existing direct mount on master re-read.

 - fix incorrect shutdown introduced by library relaod fixes.

+- improve manual umount recovery.

 4/11/2008 autofs-5.0.4

 -----------------------

diff --git a/daemon/direct.c b/daemon/direct.c

index 4f4ff20..1ed2b15 100644

--- a/daemon/direct.c

+++ b/daemon/direct.c

@@ -881,13 +881,14 @@ void *expire_proc_direct(void *arg)

 			 * avoid maintaining a file handle for control

 			 * functions as once it's mounted all opens are

 			 * directed to the mount not the trigger.

-			 * But first expire possible rootless offsets first.

 			 */

-			/* Offsets always have a real mount at their base */

+			/* Check for manual umount */

 			cache_writelock(me->mc);

-			if (strstr(next->opts, "offset")) {

-				ops->close(ap->logopt, me->ioctlfd);

+			if (me->ioctlfd != -1 && 

+			    fstat(ioctlfd, &st) != -1 &&

+			    !count_mounts(ap->logopt, next->path, st.st_dev)) {

+				ops->close(ap->logopt, ioctlfd);

 				me->ioctlfd = -1;

 				cache_unlock(me->mc);

 				pthread_setcancelstate(cur_state, NULL);

@@ -904,15 +905,6 @@ void *expire_proc_direct(void *arg)

 				continue;

 			}

-			cache_writelock(me->mc);

-			if (me->ioctlfd != -1 && 

-			    fstat(ioctlfd, &st) != -1 &&

-			    !count_mounts(ap->logopt, next->path, st.st_dev)) {

-				ops->close(ap->logopt, ioctlfd);

-				me->ioctlfd = -1;

-			}

-			cache_unlock(me->mc);

-

 			pthread_setcancelstate(cur_state, NULL);

 			continue;

 		}

@@ -1068,7 +1060,7 @@ int handle_packet_expire_direct(struct autofs_point *ap, autofs_packet_expire_di

 	map = ap->entry->maps;

 	while (map) {

 		mc = map->mc;

-		cache_readlock(mc);

+		cache_writelock(mc);

 		me = cache_lookup_ino(mc, pkt->dev, pkt->ino);

 		if (me)

 			break;

@@ -1345,7 +1337,7 @@ int handle_packet_missing_direct(struct autofs_point *ap, autofs_packet_missing_

 		}

 		mc = map->mc;

-		cache_readlock(mc);

+		cache_writelock(mc);

 		me = cache_lookup_ino(mc, pkt->dev, pkt->ino);

 		if (me)

 			break;

@@ -1367,10 +1359,10 @@ int handle_packet_missing_direct(struct autofs_point *ap, autofs_packet_missing_

 	if (me->ioctlfd != -1) {

 		/* Maybe someone did a manual umount, clean up ! */

-		ioctlfd = me->ioctlfd;

+		close(me->ioctlfd);

 		me->ioctlfd = -1;

-	} else

-		ops->open(ap->logopt, &ioctlfd, me->dev, me->key);

+	}

+	ops->open(ap->logopt, &ioctlfd, me->dev, me->key);

 	if (ioctlfd == -1) {

 		cache_unlock(mc);

diff --git a/daemon/indirect.c b/daemon/indirect.c

index 2539282..bc39e63 100644

--- a/daemon/indirect.c

+++ b/daemon/indirect.c

@@ -428,8 +428,53 @@ void *expire_proc_indirect(void *arg)

 			pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cur_state);

 			if (strstr(next->opts, "indirect"))

 				master_notify_submount(ap, next->path, ap->state);

-			pthread_setcancelstate(cur_state, NULL);

+			else if (strstr(next->opts, "offset")) {

+				struct map_source *map;

+				struct mapent_cache *mc = NULL;

+				struct mapent *me = NULL;

+				struct stat st;

+

+				master_source_readlock(ap->entry);

+

+				map = ap->entry->maps;

+				while (map) {

+					mc = map->mc;

+					cache_writelock(mc);

+					me = cache_lookup_distinct(mc, next->path);

+					if (me)

+						break;

+					cache_unlock(mc);

+					map = map->next;

+				}

+				if (!mc || !me) {

+					master_source_unlock(ap->entry);

+					pthread_setcancelstate(cur_state, NULL);

+					continue;

+				}

+

+				/* Check for manual umount */

+				if (me->ioctlfd != -1 &&

+				    (fstat(me->ioctlfd, &st) == -1 ||

+				     !count_mounts(ap->logopt, me->key, st.st_dev))) {

+					if (is_mounted(_PROC_MOUNTS, me->key, MNTS_REAL)) {

+						error(ap->logopt,

+						      "error: possible mtab mismatch %s",

+						      me->key);

+						cache_unlock(mc);

+						master_source_unlock(ap->entry);

+						pthread_setcancelstate(cur_state, NULL);

+						continue;

+					}

+					close(me->ioctlfd);

+					me->ioctlfd = -1;

+				}

+

+				cache_unlock(mc);

+				master_source_unlock(ap->entry);

+			}

+

+			pthread_setcancelstate(cur_state, NULL);

 			continue;

 		}