NFS: always treat the invocation of nfs_getattr as cache hit when noac is on

When using 'ls -l' to display a large directory, if noac option is used,
in function nfs_getattr() nfs_need_revalidate_inode() will always be true
for NFSv3 and the nfs_entry cache of the directory will be flushed. The
flush will lead to a fully reread of the directory entries from server.

To prevent the unnecessary RPCs, we need to check whether or not the
noac option is used, and always report the invocation of nfs_getattr()
as cache hit instead cache miss when it's on.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index f489a5a71bd5cd89f0667b455e04930753e24e84..1de93ba78dc95a34292cc6160198d9be7c843de1 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -734,7 +734,10 @@ int nfs_getattr(const struct path *path, struct kstat *stat,
        if (need_atime || nfs_need_revalidate_inode(inode)) {
                struct nfs_server *server = NFS_SERVER(inode);
 
-               nfs_readdirplus_parent_cache_miss(path->dentry);
+               if (!(server->flags & NFS_MOUNT_NOAC))
+                       nfs_readdirplus_parent_cache_miss(path->dentry);
+               else
+                       nfs_readdirplus_parent_cache_hit(path->dentry);
                err = __nfs_revalidate_inode(server, inode);
        } else
                nfs_readdirplus_parent_cache_hit(path->dentry);