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From:   trondmy@kernel.org
To:     Paul Menzel <pmenzel@molgen.mpg.de>,
        Anna Schumaker <Anna.Schumaker@netapp.com>
Cc:     linux-nfs@vger.kernel.org
Subject: [PATCH] NFS: LOOKUP_DIRECTORY is also ok with symlinks
Date:   Tue,  8 Feb 2022 13:38:23 -0500
Message-Id: <20220208183823.1391397-1-trondmy@kernel.org>
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From: Trond Myklebust <trond.myklebust@hammerspace.com>

Commit ac795161c936 (NFSv4: Handle case where the lookup of a directory
fails) [1], part of Linux since 5.17-rc2, introduced a regression, where
a symbolic link on an NFS mount to a directory on another NFS does not
resolve(?) the first time it is accessed:

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Fixes: ac795161c936 ("NFSv4: Handle case where the lookup of a directory fails")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/dir.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index e128503728f2..6dee4e12d381 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2051,14 +2051,14 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 	if (!res) {
 		inode = d_inode(dentry);
 		if ((lookup_flags & LOOKUP_DIRECTORY) && inode &&
-		    !S_ISDIR(inode->i_mode))
+		    !(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
 			res = ERR_PTR(-ENOTDIR);
 		else if (inode && S_ISREG(inode->i_mode))
 			res = ERR_PTR(-EOPENSTALE);
 	} else if (!IS_ERR(res)) {
 		inode = d_inode(res);
 		if ((lookup_flags & LOOKUP_DIRECTORY) && inode &&
-		    !S_ISDIR(inode->i_mode)) {
+		    !(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))) {
 			dput(res);
 			res = ERR_PTR(-ENOTDIR);
 		} else if (inode && S_ISREG(inode->i_mode)) {
-- 
2.34.1