netdev - [PATCH RFC 22/24] nfs: skip dentry revalidation when parent dir has a delegation

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Message-Id: <20240315-dir-deleg-v1-22-a1d6209a3654@kernel.org>
Date: Fri, 15 Mar 2024 12:53:13 -0400
From: Jeff Layton <jlayton@...nel.org>
To: Alexander Viro <viro@...iv.linux.org.uk>, 
 Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>, 
 Chuck Lever <chuck.lever@...cle.com>, 
 Alexander Aring <alex.aring@...il.com>, 
 Trond Myklebust <trond.myklebust@...merspace.com>, 
 Anna Schumaker <anna@...nel.org>, Steve French <sfrench@...ba.org>, 
 Paulo Alcantara <pc@...guebit.com>, 
 Ronnie Sahlberg <ronniesahlberg@...il.com>, 
 Shyam Prasad N <sprasad@...rosoft.com>, Tom Talpey <tom@...pey.com>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 "Rafael J. Wysocki" <rafael@...nel.org>, 
 David Howells <dhowells@...hat.com>, Tyler Hicks <code@...icks.com>, 
 Neil Brown <neilb@...e.de>, Olga Kornievskaia <kolga@...app.com>, 
 Dai Ngo <Dai.Ngo@...cle.com>, Miklos Szeredi <miklos@...redi.hu>, 
 Amir Goldstein <amir73il@...il.com>, Namjae Jeon <linkinjeon@...nel.org>, 
 Sergey Senozhatsky <senozhatsky@...omium.org>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-nfs@...r.kernel.org, linux-cifs@...r.kernel.org, 
 samba-technical@...ts.samba.org, netfs@...ts.linux.dev, 
 ecryptfs@...r.kernel.org, linux-unionfs@...r.kernel.org, 
 netdev@...r.kernel.org, Jeff Layton <jlayton@...nel.org>
Subject: [PATCH RFC 22/24] nfs: skip dentry revalidation when parent dir
 has a delegation

If the parent has a valid delegation, then test whether the
dentry->d_time matches the current change attr on the directory. If it
does, then we can declare the dentry valid with no further checks.

Signed-off-by: Jeff Layton <jlayton@...nel.org>
---
 fs/nfs/dir.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index ac505671efbd..061648c73116 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2188,6 +2188,15 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 }
 EXPORT_SYMBOL_GPL(nfs_atomic_open);

+static int
+nfs_lookup_revalidate_delegated_parent(struct inode *dir, struct dentry *dentry,
+				       struct inode *inode)
+{
+	return nfs_lookup_revalidate_done(dir, dentry, inode,
+					  nfs_verify_change_attribute(dir, dentry->d_time) ?
+					  1 : 0);
+}
+
 static int
 nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
 			  unsigned int flags)
@@ -2212,6 +2221,9 @@ nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
 	if (nfs_verifier_is_delegated(dentry))
 		return nfs_lookup_revalidate_delegated(dir, dentry, inode);

+	if (nfs_have_delegated_attributes(dir))
+		return nfs_lookup_revalidate_delegated_parent(dir, dentry, inode);
+
 	/* NFS only supports OPEN on regular files */
 	if (!S_ISREG(inode->i_mode))
 		goto full_reval;

-- 
2.44.0