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 <bfoster@redhat.com>
Reviewed-on: http://review.gluster.com/3676
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 41 insertions, 1 deletions

diff --git a/xlators/mount/fuse/src/fuse-helpers.c b/xlators/mount/fuse/src/fuse-helpers.c
index bcad97fc742..729c8fb2cd4 100644
--- a/xlators/mount/fuse/src/fuse-helpers.c
+++ b/xlators/mount/fuse/src/fuse-helpers.c
@@ -245,6 +245,46 @@ out:
 #endif /* GF_LINUX_HOST_OS */
 }
 
+/*
+ * Get the groups for the PID associated with this frame. If enabled,
+ * use the gid cache to reduce group list collection.
+ */
+static void get_groups(fuse_private_t *priv, call_frame_t *frame)
+{
+	int i;
+	const gid_list_t *gl;
+	gid_list_t agl;
+
+	if (!priv->gid_cache_timeout) {
+		frame_fill_groups(frame);
+		return;
+	}
+
+	gl = gid_cache_lookup(&priv->gid_cache, frame->root->pid);
+	if (gl) {
+		frame->root->ngrps = gl->gl_count;
+		for (i = 0; i < gl->gl_count; i++)
+			frame->root->groups[i] = gl->gl_list[i];
+		gid_cache_release(&priv->gid_cache, gl);
+		return;
+	}
+
+	frame_fill_groups (frame);
+
+	agl.gl_id = frame->root->pid;
+	agl.gl_count = frame->root->ngrps;
+	agl.gl_list = GF_CALLOC(frame->root->ngrps, sizeof(gid_t),
+			gf_fuse_mt_gids_t);
+	if (!agl.gl_list)
+		return;
+
+	for (i = 0; i < frame->root->ngrps; i++)
+		agl.gl_list[i] = frame->root->groups[i];
+
+	if (gid_cache_add(&priv->gid_cache, &agl) != 1)
+		GF_FREE(agl.gl_list);
+}
+
 call_frame_t *
 get_call_frame_for_req (fuse_state_t *state)
 {
@@ -272,7 +312,7 @@ get_call_frame_for_req (fuse_state_t *state)
                                           state->lk_owner);
         }
 
-        frame_fill_groups (frame);
+	get_groups(priv, frame);
 
         if (priv && priv->client_pid_set)
                 frame->root->pid = priv->client_pid;