fs: provide no_revalidate_d_ops for network file systems

Networked file systems may wish to forego dentry caching altogether, so
every lookup goes over the network and stale data is avoided.
Provide a no_revalidate_d_ops helper object that does this.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 9 insertions, 0 deletions

diff --git a/fs/fs.c b/fs/fs.c
index c6cb49996e..dda19db913 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -1262,6 +1262,15 @@ static void d_invalidate(struct dentry *dentry)
 {
 }
 
+static int d_no_revalidate(struct dentry *dir, unsigned int flags)
+{
+	return 0;
+}
+
+const struct dentry_operations no_revalidate_d_ops = {
+	.d_revalidate = d_no_revalidate,
+};
+
 static inline int d_revalidate(struct dentry *dentry, unsigned int flags)
 {
 	if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE))