From: Anna Schumaker <anna.schumaker@oracle.com>
Date: Tue, 4 Nov 2025 15:06:45 +0000 (-0500)
Subject: NFS: Add a module option to disable directory delegations
X-Git-Tag: v6.19-rc1~27^2~9
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b6d2a520f4638c2e7d3f2f11946918946941be18;p=thirdparty%2Flinux.git

NFS: Add a module option to disable directory delegations

When this option is disabled then the client will not request directory
delegations or check if we have one during the revalidation paths.

Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index b4c192f00e94..2248e3ad089a 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -30,6 +30,11 @@
 static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK;
 module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);
 
+bool directory_delegations = true;
+module_param(directory_delegations, bool, 0644);
+MODULE_PARM_DESC(directory_delegations,
+		 "Enable the use of directory delegations, defaults to on.");
+
 static struct hlist_head *nfs_delegation_hash(struct nfs_server *server,
 		const struct nfs_fh *fhandle)
 {
@@ -143,6 +148,8 @@ static int nfs4_do_check_delegation(struct inode *inode, fmode_t type,
  */
 int nfs4_have_delegation(struct inode *inode, fmode_t type, int flags)
 {
+	if (S_ISDIR(inode->i_mode) && !directory_delegations)
+		nfs_inode_evict_delegation(inode);
 	return nfs4_do_check_delegation(inode, type, flags, true);
 }
 
diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h
index 8968f62bf438..46d866adb5c2 100644
--- a/fs/nfs/delegation.h
+++ b/fs/nfs/delegation.h
@@ -124,6 +124,8 @@ static inline int nfs_have_delegated_mtime(struct inode *inode)
 						 NFS_DELEGATION_FLAG_TIME);
 }
 
+extern bool directory_delegations;
+
 static inline void nfs_request_directory_delegation(struct inode *inode)
 {
 	if (S_ISDIR(inode->i_mode))
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 6691a44866b6..c53ddb185aa3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4473,6 +4473,8 @@ out:
 #if IS_ENABLED(CONFIG_NFS_V4_1)
 static bool should_request_dir_deleg(struct inode *inode)
 {
+	if (!directory_delegations)
+		return false;
 	if (!inode)
 		return false;
 	if (!S_ISDIR(inode->i_mode))