fuse: add "resolve-gids" mount option to overcome 32-groups limit

Add a --resolve-gids commandline option to the glusterfs binary. This
option gets set when executing "mount -t glusterfs -o resolve-gids ...".

This option is most useful in combination with the "acl" mount option.
POSIX ACL permission checking is done on the FUSE-client side to improve
performance (in addition to the checking on the bricks).

The fuse-bridge reads /proc/$PID/status by default, and this file
contains maximum 32 groups. Any local (client-side) permission checking
that requires more than the first 32 groups will fail.

By enabling the "resolve-gids" option, the fuse-bridge will call
getgrouplist() to retrieve all the groups from the user accessing the
mountpoint. This is comparable to how "nfs.server-aux-gids" works.

Note that when a user belongs to more than ~93 groups, the volume option
server.manage-gids needs to be enabled too. Without this option, the
RPC-layer will need to reduce the number of groups to make them fit in
the RPC-header.

Change-Id: I7ede90d0e41bcf55755cced5747fa0fb1699edb2
BUG: 1246275
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/11732
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Ravishankar N <ravishankar@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: jiffin tony Thottan <jthottan@redhat.com>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/xlators/mount/fuse/src/fuse-bridge.h b/xlators/mount/fuse/src/fuse-bridge.h
index a9705d6c654..850eeb60ea8 100644
--- a/xlators/mount/fuse/src/fuse-bridge.h
+++ b/xlators/mount/fuse/src/fuse-bridge.h
@@ -127,6 +127,9 @@ struct fuse_private {
         /* fini started, helps prevent multiple epoll worker threads
          * firing up the fini routine */
         gf_boolean_t fini_invoked;
+
+        /* resolve gid with getgrouplist() instead of /proc/%d/status */
+        gf_boolean_t resolve_gids;
 };
 typedef struct fuse_private fuse_private_t;