Expose the maximum cache size setting as a flag

Allow the user to customize the size of the sshfs cache by adding a new
max_cache_size flag and turning the hardcoded constant into a variable.

3 files changed, 8 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 02fee35..066f553 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,8 @@ Draft notes for upcoming release
 
 * Integrated osxfuse's copy of sshfs, which means that sshfs now works
   on OS X out of the box.
+* Added -o cache_max_size=N option to let users tune the maximum size of
+  the cache in number of entries.
 
 Release 2.7 (2015-01-28)
 ------------------------
diff --git a/cache.c b/cache.c
index 86978c7..5a5af89 100644
--- a/cache.c
+++ b/cache.c
@@ -15,7 +15,7 @@
 #include <pthread.h>
 
 #define DEFAULT_CACHE_TIMEOUT_SECS 20
-#define MAX_CACHE_SIZE 10000
+#define DEFAULT_MAX_CACHE_SIZE 10000
 #define MIN_CACHE_CLEAN_INTERVAL 5
 #define CACHE_CLEAN_INTERVAL 60
 
@@ -24,6 +24,7 @@ struct cache {
 	unsigned stat_timeout_secs;
 	unsigned dir_timeout_secs;
 	unsigned link_timeout_secs;
+	unsigned max_size;
 	struct fuse_cache_operations *next_oper;
 	GHashTable *table;
 	pthread_mutex_t lock;
@@ -71,7 +72,7 @@ static void cache_clean(void)
 {
 	time_t now = time(NULL);
 	if (now > cache.last_cleaned + MIN_CACHE_CLEAN_INTERVAL &&
-	    (g_hash_table_size(cache.table) > MAX_CACHE_SIZE ||
+	    (g_hash_table_size(cache.table) > cache.max_size ||
 	     now > cache.last_cleaned + CACHE_CLEAN_INTERVAL)) {
 		g_hash_table_foreach_remove(cache.table,
 					    (GHRFunc) cache_clean_entry, &now);
@@ -576,6 +577,7 @@ static const struct fuse_opt cache_opts[] = {
 	{ "cache_stat_timeout=%u", offsetof(struct cache, stat_timeout_secs), 0 },
 	{ "cache_dir_timeout=%u", offsetof(struct cache, dir_timeout_secs), 0 },
 	{ "cache_link_timeout=%u", offsetof(struct cache, link_timeout_secs), 0 },
+	{ "cache_max_size=%u", offsetof(struct cache, max_size), 0 },
 	FUSE_OPT_END
 };
 
@@ -584,6 +586,7 @@ int cache_parse_options(struct fuse_args *args)
 	cache.stat_timeout_secs = DEFAULT_CACHE_TIMEOUT_SECS;
 	cache.dir_timeout_secs = DEFAULT_CACHE_TIMEOUT_SECS;
 	cache.link_timeout_secs = DEFAULT_CACHE_TIMEOUT_SECS;
+	cache.max_size = DEFAULT_MAX_CACHE_SIZE;
 	cache.on = 1;
 
 	return fuse_opt_parse(args, &cache, cache_opts, NULL);
diff --git a/sshfs.c b/sshfs.c
index 84b2359..b010828 100644
--- a/sshfs.c
+++ b/sshfs.c
@@ -3377,6 +3377,7 @@ static void usage(const char *progname)
 "    -o sync_readdir        synchronous readdir\n"
 "    -o sshfs_debug         print some debugging information\n"
 "    -o cache=BOOL          enable caching {yes,no} (default: yes)\n"
+"    -o cache_max_size=N    sets the maximum size of the cache (default: 10000)\n"
 "    -o cache_timeout=N     sets timeout for caches in seconds (default: 20)\n"
 "    -o cache_X_timeout=N   sets timeout for {stat,dir,link} cache\n"
 "    -o workaround=LIST     colon separated list of workarounds\n"