1 files changed, 31 insertions, 2 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 82b42e2ea65c..d0884c0d9464 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -475,6 +475,29 @@ different:
 }
 
 static
+bool nfs_use_readdirplus(struct inode *dir, struct file *filp)
+{
+	if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS))
+		return false;
+	if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags))
+		return true;
+	if (filp->f_pos == 0)
+		return true;
+	return false;
+}
+
+/*
+ * This function is called by the lookup code to request the use of
+ * readdirplus to accelerate any future lookups in the same
+ * directory.
+ */
+static
+void nfs_advise_use_readdirplus(struct inode *dir)
+{
+	set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags);
+}
+
+static
 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
 {
 	struct qstr filename = {
@@ -874,7 +897,7 @@ static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 	desc->file = filp;
 	desc->dir_cookie = &dir_ctx->dir_cookie;
 	desc->decode = NFS_PROTO(inode)->decode_dirent;
-	desc->plus = NFS_USE_READDIRPLUS(inode);
+	desc->plus = nfs_use_readdirplus(inode, filp) ? 1 : 0;
 
 	nfs_block_sillyrename(dentry);
 	res = nfs_revalidate_mapping(inode, filp->f_mapping);
@@ -1114,7 +1137,7 @@ static int nfs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd)
 	if (!inode) {
 		if (nfs_neg_need_reval(dir, dentry, nd))
 			goto out_bad;
-		goto out_valid;
+		goto out_valid_noent;
 	}
 
 	if (is_bad_inode(inode)) {
@@ -1156,6 +1179,9 @@ static int nfs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd)
 out_set_verifier:
 	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
  out_valid:
+	/* Success: notify readdir to use READDIRPLUS */
+	nfs_advise_use_readdirplus(dir);
+ out_valid_noent:
 	dput(parent);
 	dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n",
 			__func__, dentry->d_parent->d_name.name,
@@ -1311,6 +1337,9 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru
 	if (IS_ERR(res))
 		goto out_unblock_sillyrename;
 
+	/* Success: notify readdir to use READDIRPLUS */
+	nfs_advise_use_readdirplus(dir);
+
 no_entry:
 	res = d_materialise_unique(dentry, inode);
 	if (res != NULL) {