linux-kernel - [PATCH 5.4 147/168] NFS: Dont gratuitously clear the inode cache when lookup failed

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Message-Id: <20210315135555.168479516@linuxfoundation.org>
Date:   Mon, 15 Mar 2021 14:56:19 +0100
From:   gregkh@...uxfoundation.org
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Trond Myklebust <trond.myklebust@...merspace.com>,
        Anna Schumaker <Anna.Schumaker@...app.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 147/168] NFS: Dont gratuitously clear the inode cache when lookup failed

From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

From: Trond Myklebust <trond.myklebust@...merspace.com>

[ Upstream commit 47397915ede0192235474b145ebcd81b37b03624 ]

The fact that the lookup revalidation failed, does not mean that the
inode contents have changed.

Fixes: 5ceb9d7fdaaf ("NFS: Refactor nfs_lookup_revalidate()")
Signed-off-by: Trond Myklebust <trond.myklebust@...merspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@...app.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/nfs/dir.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 59092d2780a3..e7c0790308fe 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1116,18 +1116,14 @@ nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry,
 			__func__, dentry);
 		return 1;
 	case 0:
-		if (inode && S_ISDIR(inode->i_mode)) {
-			/* Purge readdir caches. */
-			nfs_zap_caches(inode);
-			/*
-			 * We can't d_drop the root of a disconnected tree:
-			 * its d_hash is on the s_anon list and d_drop() would hide
-			 * it from shrink_dcache_for_unmount(), leading to busy
-			 * inodes on unmount and further oopses.
-			 */
-			if (IS_ROOT(dentry))
-				return 1;
-		}
+		/*
+		 * We can't d_drop the root of a disconnected tree:
+		 * its d_hash is on the s_anon list and d_drop() would hide
+		 * it from shrink_dcache_for_unmount(), leading to busy
+		 * inodes on unmount and further oopses.
+		 */
+		if (inode && IS_ROOT(dentry))
+			return 1;
 		dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n",
 				__func__, dentry);
 		return 0;
-- 
2.30.1