NFS: new idmapper

This patch creates a new idmapper system that uses the request-key function to
place a call into userspace to map user and group ids to names.  The old
idmapper was single threaded, which prevented more than one request from running
at a single time.  This means that a user would have to wait for an upcall to
finish before accessing a cached result.

The upcall result is stored on a keyring of type id_resolver.  See the file
Documentation/filesystems/nfs/idmapper.txt for instructions.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
[Trond: fix up the return value of nfs_idmap_lookup_name and clean up code]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/nfs/sysctl.c b/fs/nfs/sysctl.c
index ad4d2e787b20..978aaeb8a093 100644
--- a/fs/nfs/sysctl.c
+++ b/fs/nfs/sysctl.c
@@ -32,6 +32,7 @@ static ctl_table nfs_cb_sysctls[] = {
                 .extra1 = (int *)&nfs_set_port_min,
                 .extra2 = (int *)&nfs_set_port_max,
         },
+#ifndef CONFIG_NFS_USE_NEW_IDMAPPER
         {
                 .procname = "idmap_cache_timeout",
                 .data = &nfs_idmap_cache_timeout,
@@ -39,6 +40,7 @@ static ctl_table nfs_cb_sysctls[] = {
                 .mode = 0644,
                 .proc_handler = proc_dointvec_jiffies,
         },
+#endif /* CONFIG_NFS_USE_NEW_IDMAPPER */
 #endif
         {
                 .procname       = "nfs_mountpoint_timeout",