autofs-5.1.7 - eliminate clean_stale_multi_triggers()
From: Ian Kent <raven@themaw.net>
Eliminate clean_stale_multi_triggers() by checking for stale offsets at
the time mount_subtree() is called.
This should result in the same behaviour but eliminate an additional
seperate traversal of the offset list.
Signed-off-by: Ian Kent <raven@themaw.net>
---
CHANGELOG | 1
lib/mounts.c | 209 ++++++++++-----------------------------------------
modules/parse_sun.c | 10 --
3 files changed, 43 insertions(+), 177 deletions(-)
diff --git a/CHANGELOG b/CHANGELOG
index 5a3bedc1..b1ce7b69 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -12,6 +12,7 @@
- remove redundant variables from mount_autofs_offset().
- remove unused parameter form do_mount_autofs_offset().
- refactor umount_multi_triggers().
+- eliminate clean_stale_multi_triggers().
25/01/2021 autofs-5.1.7
- make bind mounts propagation slave by default.
diff --git a/lib/mounts.c b/lib/mounts.c
index 5268ba5b..a9abbebf 100644
--- a/lib/mounts.c
+++ b/lib/mounts.c
@@ -2601,10 +2601,44 @@ static int do_umount_offset(struct autofs_point *ap, struct mapent *oe, const ch
oe_base = oe->key + strlen(root);
left += do_umount_multi_triggers(ap, oe, root, oe_base);
+ /*
+ * If an offset that has an active mount has been removed
+ * from the multi-mount we don't want to attempt to trigger
+ * mounts for it. Obviously this is because it has been
+ * removed, but less obvious is the potential strange
+ * behaviour that can result if we do try and mount it
+ * again after it's been expired. For example, if an NFS
+ * file system is no longer exported and is later umounted
+ * it can be mounted again without any error message but
+ * shows as an empty directory. That's going to confuse
+ * people for sure.
+ *
+ * If the mount cannot be umounted (the process is now
+ * using a stale mount) the offset needs to be invalidated
+ * so no further mounts will be attempted but the offset
+ * cache entry must remain so expires can continue to
+ * attempt to umount it. If the mount can be umounted and
+ * the offset is removed, at least for NFS we will get
+ * ESTALE errors when attempting list the directory.
+ */
if (oe->ioctlfd != -1 ||
is_mounted(oe->key, MNTS_REAL)) {
- left++;
- return left;
+ if (umount_ent(ap, oe->key) &&
+ is_mounted(oe->key, MNTS_REAL)) {
+ debug(ap->logopt,
+ "offset %s has active mount, invalidate",
+ oe->key);
+ /*
+ * Ok, so we shouldn't modify the mapent but
+ * mount requests are blocked at a point above
+ * this and expire only uses the mapent key.
+ */
+ if (oe->mapent) {
+ free(oe->mapent);
+ oe->mapent = NULL;
+ }
+ return ++left;
+ }
}
debug(ap->logopt, "umount offset %s", oe->key);
@@ -2666,6 +2700,11 @@ int mount_multi_triggers(struct autofs_point *ap, struct mapent *me,
oe = cache_lookup_distinct(me->mc, key);
if (!oe || !oe->mapent)
goto cont;
+ if (oe->age != me->multi->age) {
+ /* Best effort */
+ do_umount_offset(ap, oe, root);
+ goto cont;
+ }
mounted += do_mount_autofs_offset(ap, oe, root);
@@ -2725,169 +2764,3 @@ int umount_multi_triggers(struct autofs_point *ap, struct mapent *me, char *root
return left;
}
-
-int clean_stale_multi_triggers(struct autofs_point *ap,
- struct mapent *me, char *top, const char *base)
-{
- char *root;
- char mm_top[PATH_MAX + 1];
- char path[PATH_MAX + 1];
- char *offset;
- struct mapent *oe;
- struct list_head *mm_root, *pos;
- const char o_root[] = "/";
- const char *mm_base;
- int left, start;
- unsigned int root_len;
- unsigned int mm_base_len;
- time_t age;
-
- if (top)
- root = top;
- else {
- if (!strchr(me->multi->key, '/'))
- /* Indirect multi-mount root */
- /* sprintf okay - if it's mounted, it's
- * PATH_MAX or less bytes */
- sprintf(mm_top, "%s/%s", ap->path, me->multi->key);
- else
- strcpy(mm_top, me->multi->key);
- root = mm_top;
- }
-
- left = 0;
- start = strlen(root);
-
- mm_root = &me->multi->multi_list;
-
- if (!base)
- mm_base = o_root;
- else
- mm_base = base;
-
- pos = NULL;
- offset = path;
- root_len = start;
- mm_base_len = strlen(mm_base);
- age = me->multi->age;
-
- while ((offset = cache_get_offset(mm_base, offset, start, mm_root, &pos))) {
- char key[PATH_MAX + 1];
- int key_len = root_len + strlen(offset);
- char *oe_base;
- int ret;
-
- if (mm_base_len > 1)
- key_len += mm_base_len;
-
- if (key_len > PATH_MAX) {
- warn(ap->logopt, "path loo long");
- continue;
- }
-
- strcpy(key, root);
- if (mm_base_len > 1)
- strcat(key, mm_base);
- strcat(key, offset);
-
- oe = cache_lookup_distinct(me->mc, key);
- /* root offset is a special case */
- if (!oe || (strlen(oe->key) - start) == 1)
- continue;
-
- /* Check for and umount stale subtree offsets */
- oe_base = oe->key + strlen(root);
- ret = clean_stale_multi_triggers(ap, oe, root, oe_base);
- left += ret;
- if (ret)
- continue;
-
- if (oe->age == age)
- continue;
-
- /*
- * If an offset that has an active mount has been removed
- * from the multi-mount we don't want to attempt to trigger
- * mounts for it. Obviously this is because it has been
- * removed, but less obvious is the potential strange
- * behaviour that can result if we do try and mount it
- * again after it's been expired. For example, if an NFS
- * file system is no longer exported and is later umounted
- * it can be mounted again without any error message but
- * shows as an empty directory. That's going to confuse
- * people for sure.
- *
- * If the mount cannot be umounted (the process is now
- * using a stale mount) the offset needs to be invalidated
- * so no further mounts will be attempted but the offset
- * cache entry must remain so expires can continue to
- * attempt to umount it. If the mount can be umounted and
- * the offset is removed, at least for NFS we will get
- * ESTALE errors when attempting list the directory.
- */
- if (oe->ioctlfd != -1 ||
- is_mounted(oe->key, MNTS_REAL)) {
- if (umount_ent(ap, oe->key) &&
- is_mounted(oe->key, MNTS_REAL)) {
- debug(ap->logopt,
- "offset %s has active mount, invalidate",
- oe->key);
- if (oe->mapent) {
- free(oe->mapent);
- oe->mapent = NULL;
- }
- left++;
- continue;
- }
- }
-
- debug(ap->logopt, "umount offset %s", oe->key);
-
- if (umount_autofs_offset(ap, oe)) {
- warn(ap->logopt, "failed to umount offset %s", key);
- left++;
- } else {
- struct stat st;
-
- /* Mount point not ours to delete ? */
- if (!(oe->flags & MOUNT_FLAG_DIR_CREATED)) {
- debug(ap->logopt, "delete offset key %s", key);
- if (cache_delete_offset(oe->mc, key) == CHE_FAIL)
- error(ap->logopt,
- "failed to delete offset key %s", key);
- continue;
- }
-
- /*
- * An error due to partial directory removal is
- * ok so only try and remount the offset if the
- * actual mount point still exists.
- */
- ret = rmdir_path_offset(ap, oe);
- if (ret == -1 && !stat(oe->key, &st)) {
- ret = do_mount_autofs_offset(ap, oe, root);
- if (ret) {
- left++;
- /* But we did origianlly create this */
- oe->flags |= MOUNT_FLAG_DIR_CREATED;
- continue;
- }
- /*
- * Fall through if the trigger can't be mounted
- * again, since there is no offset there can't
- * be any mount requests so remove the map
- * entry from the cache. There's now a dead
- * offset mount, but what else can we do ....
- */
- }
-
- debug(ap->logopt, "delete offset key %s", key);
-
- if (cache_delete_offset(oe->mc, key) == CHE_FAIL)
- error(ap->logopt,
- "failed to delete offset key %s", key);
- }
- }
-
- return left;
-}
diff --git a/modules/parse_sun.c b/modules/parse_sun.c
index f42af7b7..f4d5125c 100644
--- a/modules/parse_sun.c
+++ b/modules/parse_sun.c
@@ -1176,7 +1176,7 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
/* Mount root offset if it exists */
ro = cache_lookup_distinct(me->mc, key);
- if (ro) {
+ if (ro && ro->age == me->multi->age) {
char *myoptions, *ro_loc;
int namelen = name ? strlen(name) : 0;
int ro_len;
@@ -1610,14 +1610,6 @@ dont_expand:
free(myoptions);
} while (*p == '/' || (*p == '"' && *(p + 1) == '/'));
- /*
- * We've got the ordered list of multi-mount entries so go
- * through and remove any stale entries if this is the top
- * of the multi-mount and set the parent entry of each.
- */
- if (me == me->multi)
- clean_stale_multi_triggers(ap, me, NULL, NULL);
-
rv = mount_subtree(ap, me, name, NULL, options, ctxt);
cache_multi_unlock(me);