On Fri, 2009-01-16 at 10:43 +0900, Ian Kent wrote:
> > >
> > > I'm tending toward reading the map during the lookup so the map is up to
> > > date when we look for the key in the cache.
>
> Or maybe not.
>
> If we take advantage of the existing code to mark the map as stale and
> handle the re-read and we accept the overhead of scanning the file map
> while waiting for the update something like this could be all that's
> needed.
So here is a slightly updated patch.
autofs-5.0.4 - always read file maps
From: Ian Kent <ra...@themaw.net>
---
daemon/lookup.c | 9 ++++++---
modules/lookup_file.c | 26 ++++++++++++++------------
2 files changed, 20 insertions(+), 15 deletions(-)
diff --git a/daemon/lookup.c b/daemon/lookup.c
index 741d846..e034348 100644
--- a/daemon/lookup.c
+++ b/daemon/lookup.c
@@ -283,10 +283,13 @@ static int do_read_map(struct autofs_point *ap, struct
map_source *map, time_t a
* for the fail cases to function correctly and to cache the
* lookup handle.
*
- * We always need to whole map for direct mounts in order to
- * mount the triggers.
+ * We always need to read the whole map for direct mounts in
+ * order to mount the triggers. We also want to read the whole
+ * map if it's a file map to avoid potentially lengthy linear
+ * file scanning.
*/
- if (!(ap->flags & MOUNT_FLAG_GHOST) && ap->type != LKP_DIRECT)
+ if (strcmp(map->type, "file") &&
+ !(ap->flags & MOUNT_FLAG_GHOST) && ap->type != LKP_DIRECT)
return NSS_STATUS_SUCCESS;
if (!map->stale)
diff --git a/modules/lookup_file.c b/modules/lookup_file.c
index 95b9f6f..6f426a5 100644
--- a/modules/lookup_file.c
+++ b/modules/lookup_file.c
@@ -93,7 +93,6 @@ int lookup_init(const char *mapfmt, int argc, const char
*const *argv, void **co
argv[0]);
return 1;
}
-
ctxt->mtime = st.st_mtime;
if (!mapfmt)
@@ -951,9 +950,6 @@ static int check_map_indirect(struct autofs_point *ap,
if (ret == CHE_FAIL)
return NSS_STATUS_NOTFOUND;
- if (ret & CHE_UPDATED)
- source->stale = 1;
-
pthread_cleanup_push(cache_lock_cleanup, mc);
cache_writelock(mc);
exists = cache_lookup_distinct(mc, key);
@@ -963,7 +959,6 @@ static int check_map_indirect(struct autofs_point *ap,
free(exists->mapent);
exists->mapent = NULL;
exists->status = 0;
- source->stale = 1;
}
}
pthread_cleanup_pop(1);
@@ -985,14 +980,8 @@ static int check_map_indirect(struct autofs_point *ap,
we = cache_lookup_distinct(mc, "*");
if (we) {
/* Wildcard entry existed and is now gone */
- if (we->source == source && (wild & CHE_MISSING)) {
+ if (we->source == source && (wild & CHE_MISSING))
cache_delete(mc, "*");
- source->stale = 1;
- }
- } else {
- /* Wildcard not in map but now is */
- if (wild & (CHE_OK | CHE_UPDATED))
- source->stale = 1;
}
pthread_cleanup_pop(1);
@@ -1064,7 +1053,19 @@ int lookup_mount(struct autofs_point *ap, const char
*name, int name_len, void *
if (ap->type == LKP_INDIRECT && *key != '/') {
char *lkp_key;
+ /*
+ * We can skip the map lookup and cache update altogether
+ * if we know the map hasn't been modified since it was
+ * last read. If it has then we can mark the map stale
+ * so a re-read is triggered following the lookup.
+ */
cache_readlock(mc);
+ me = cache_lookup_first(mc);
+ if (me && ctxt->mtime <= me->age)
+ goto do_cache_lookup;
+ else
+ source->stale = 1;
+
me = cache_lookup_distinct(mc, key);
if (me && me->multi)
lkp_key = strdup(me->multi->key);
@@ -1088,6 +1089,7 @@ int lookup_mount(struct autofs_point *ap, const char
*name, int name_len, void *
}
cache_readlock(mc);
+do_cache_lookup:
me = cache_lookup(mc, key);
/* Stale mapent => check for entry in alternate source or wildcard */
if (me && !me->mapent) {
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