From f5a73672d1811f2fb1dcb62ca90ceb12b2050ae7 Mon Sep 17 00:00:00 2001 From: Neil Brown Date: Tue, 10 Aug 2010 10:20:05 -0400 Subject: [PATCH] NFS: allow close-to-open cache semantics to apply to root of NFS filesystem To obey NFS cache semantics, the client must verify the cached attributes when a file is opened. In most cases this is done by a call to d_validate as one of the last steps in path_walk. However for the root of a filesystem, d_validate is only ever called on the mounted-on filesystem (except when the path ends '.' or '..'). So NFS has no chance to validate the attributes. So, in nfs_opendir, we revalidate the attributes if the opened directory is the mountpoint. This may cause double-validation for "." and ".." lookups, but that is better than missing regular /path/name lookups completely. Signed-off-by: NeilBrown Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 29539ceeb745..bd91b2778315 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -140,6 +140,13 @@ nfs_opendir(struct inode *inode, struct file *filp) /* Call generic open code in order to cache credentials */ res = nfs_open(inode, filp); + if (filp->f_path.dentry == filp->f_path.mnt->mnt_root) { + /* This is a mountpoint, so d_revalidate will never + * have been called, so we need to refresh the + * inode (for close-open consistency) ourselves. + */ + __nfs_revalidate_inode(NFS_SERVER(inode), inode); + } return res; } -- 2.20.1