autofs-5.1.7 - simplify cache_get_parent()

From: Ian Kent <raven@themaw.net>

Eliminate the list traversal from get_parent() and rename it to

get_offset_parent() to better describe it's usage.

Signed-off-by: Ian Kent <raven@themaw.net>

---

 CHANGELOG   |    1 +

 lib/cache.c |   46 ++++++++++++++++++++++++++++------------------

 2 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG

index e55fd66a..ee746277 100644

--- a/CHANGELOG

+++ b/CHANGELOG

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

 - Fix option for master read wait.

 - eliminate cache_lookup_offset() usage.

 - fix is mounted check on non existent path.

+- simplify cache_get_parent().

 25/01/2021 autofs-5.1.7

 - make bind mounts propagation slave by default.

diff --git a/lib/cache.c b/lib/cache.c

index d3b6642b..53f290cd 100644

--- a/lib/cache.c

+++ b/lib/cache.c

@@ -827,47 +827,57 @@ void cache_update_negative(struct mapent_cache *mc,

 }

-static struct mapent *get_parent(const char *key, struct list_head *head, struct list_head **pos)

+static struct mapent *get_offset_parent(struct mapent_cache *mc,

+					const char *key)

 {

-	struct list_head *next;

-	struct mapent *this, *last;

-	int eq;

+	struct mapent *me;

+	char *parent, *tail;

+	int key_len;

-	last = NULL;

-	next = *pos ? (*pos)->next : head->next;

+	key_len = strlen(key);

-	list_for_each(next, head) {

-		this = list_entry(next, struct mapent, multi_list);

+	/* Check if this is the root offset */

+	if (key[key_len - 1] == '/')

+		return NULL;

+

+	parent = strdup(key);

+	tail = &parent[key_len - 1];

-		if (!strcmp(this->key, key))

+	while (*tail) {

+		while (*tail != '/')

+			tail--;

+

+		*tail = 0;

+

+		tail--;

+		if (tail == parent)

 			break;

-		eq = strncmp(this->key, key, strlen(this->key));

-		if (eq == 0) {

-			*pos = next;

-			last = this;

-			continue;

+		me = cache_lookup_distinct(mc, parent);

+		if (me) {

+			free(parent);

+			return me;

 		}

 	}

+	free(parent);

-	return last;

+	return NULL;

 }

 int cache_set_parents(struct mapent *mm)

 {

-	struct list_head *multi_head, *p, *pos;

+	struct list_head *multi_head, *p;

 	struct mapent *this;

 	if (!mm->multi)

 		return 0;

-	pos = NULL;

 	multi_head = &mm->multi->multi_list;

 	list_for_each(p, multi_head) {

 		struct mapent *parent;

 		this = list_entry(p, struct mapent, multi_list);

-		parent = get_parent(this->key, multi_head, &pos;;

+		parent = get_offset_parent(mm->mc, this->key);

 		if (parent)

 			this->parent = parent;

 		else