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, 7 insertions, 0 deletions

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 18be041abd23..f2d2c801e0af 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1526,6 +1526,10 @@ static int __init init_nfs_fs(void)
 {
         int err;
 
+        err = nfs_idmap_init();
+        if (err < 0)
+                goto out9;
+
         err = nfs_dns_resolver_init();
         if (err < 0)
                 goto out8;
@@ -1590,6 +1594,8 @@ out6:
 out7:
         nfs_dns_resolver_destroy();
 out8:
+        nfs_idmap_quit();
+out9:
         return err;
 }
 
@@ -1602,6 +1608,7 @@ static void __exit exit_nfs_fs(void)
         nfs_destroy_nfspagecache();
         nfs_fscache_unregister();
         nfs_dns_resolver_destroy();
+        nfs_idmap_quit();
 #ifdef CONFIG_PROC_FS
         rpc_proc_unregister("nfs");
 #endif