path: root/libglusterfs/src/gidcache.h
diff options
authorBrian Foster <>2012-07-16 13:51:09 -0400
committerAnand Avati <>2012-07-17 08:11:48 -0700
commit59ff893d11844eb52453ce4f7f098df05fcde174 (patch)
tree25d332376a461e09770e7dfdd88e7cfc13efea4b /libglusterfs/src/gidcache.h
parent911603eb0e1c85e79cf261f99f442c833ead8178 (diff)
libglusterfs,mount/fuse: implement gidcache mechanism in fuse-bridge
This change genericizes the cache mechanism implemented in commit 8efd2845 into libglusterfs/src/gidcache.[ch] and adds fuse-bridge as a client. The cache mechanism is fundamentally equivalent, with some minor changes: - Change cache key from uid_t to uint64_t. - Modify the cache add logic to locate and use an entry with a matching ID, should it already exist. This addresses a bug in the existing mechanism where an expired entry supercedes a newly added entry in lookup, causing repeated adds and flushing of a cache bucket. The fuse group cache is disabled by default. It can be enabled via the 'gid-timeout' fuse-bridge translator option and accompanying mount option (i.e., '-o gid-timeout=1' for a 1s entry timeout). BUG: 800892 Change-Id: I0b34a2263ca48dbb154790a4a44fc70b733e9114 Signed-off-by: Brian Foster <> Reviewed-on: Tested-by: Gluster Build System <> Reviewed-by: Jeff Darcy <> Reviewed-by: Anand Avati <>
Diffstat (limited to 'libglusterfs/src/gidcache.h')
1 files changed, 52 insertions, 0 deletions
diff --git a/libglusterfs/src/gidcache.h b/libglusterfs/src/gidcache.h
new file mode 100644
index 000000000..f904f26eb
--- /dev/null
+++ b/libglusterfs/src/gidcache.h
@@ -0,0 +1,52 @@
+ Copyright (c) 2008-2012 Red Hat, Inc. <>
+ This file is part of GlusterFS.
+ This file is licensed to you under your choice of the GNU Lesser
+ General Public License, version 3 or any later version (LGPLv3 or
+ later), or the GNU General Public License, version 2 (GPLv2), in all
+ cases as published by the Free Software Foundation.
+#ifndef __GIDCACHE_H__
+#define __GIDCACHE_H__
+#include "glusterfs.h"
+#include "locking.h"
+ * TBD: make the cache size tunable
+ *
+ * The current size represents a pretty trivial amount of memory, and should
+ * provide good hit rates even for quite busy systems. If we ever want to
+ * support really large cache sizes, we'll need to do dynamic allocation
+ * instead of just defining an array within a private structure. It doesn't make
+ * a whole lot of sense to change the associativity, because it won't improve
+ * hit rates all that much and will increase the maintenance cost as we have
+ * to scan more entries with every lookup/update.
+ */
+typedef struct {
+ uint64_t gl_id;
+ int gl_count;
+ gid_t *gl_list;
+ time_t gl_deadline;
+} gid_list_t;
+typedef struct {
+ gf_lock_t gc_lock;
+ uint32_t gc_max_age;
+ unsigned int gc_nbuckets;
+ gid_list_t gc_cache[AUX_GID_CACHE_SIZE];
+} gid_cache_t;
+int gid_cache_init(gid_cache_t *, uint32_t);
+const gid_list_t *gid_cache_lookup(gid_cache_t *, uint64_t);
+void gid_cache_release(gid_cache_t *, const gid_list_t *);
+int gid_cache_add(gid_cache_t *, gid_list_t *);
+#endif /* __GIDCACHE_H__ */