NFS: Add options for finer control of the lookup cache

Add the flag NFS_MOUNT_LOOKUP_CACHE_NONEG to turn off the caching of
negative dentries. In reality what we do is to force
nfs_lookup_revalidate() to always discard negative dentries.

Add the flag NFS_MOUNT_LOOKUP_CACHE_NONE for enforcing stricter
revalidation of dentries. It forces the revalidate code to always do a
lookup instead of just checking the cached mtime of the parent directory.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/nfs_mount.h b/include/linux/nfs_mount.h
index df7c6b7a7ebb..6549a06ac16e 100644
--- a/include/linux/nfs_mount.h
+++ b/include/linux/nfs_mount.h
@@ -65,4 +65,8 @@ struct nfs_mount_data {
 #define NFS_MOUNT_UNSHARED      0x8000  /* 5 */
 #define NFS_MOUNT_FLAGMASK      0xFFFF
 
+/* The following are for internal use only */
+#define NFS_MOUNT_LOOKUP_CACHE_NONEG    0x10000
+#define NFS_MOUNT_LOOKUP_CACHE_NONE     0x20000
+
 #endif