The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1751fc1db36f6f411709e143d5393f92d12137a9 Mon Sep 17 00:00:00 2001 From: Trond Myklebust trond.myklebust@hammerspace.com Date: Thu, 6 Jan 2022 18:24:03 -0500 Subject: [PATCH] NFSv4: nfs_atomic_open() can race when looking up a non-regular file

If the file type changes back to being a regular file on the server between the failed OPEN and our LOOKUP, then we need to re-run the OPEN.

Fixes: 0dd2b474d0b6 ("nfs: implement i_op->atomic_open()") Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Anna Schumaker Anna.Schumaker@Netapp.com

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 408c3bb549b1..5df75ed09268 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1999,12 +1999,17 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry, if ((lookup_flags & LOOKUP_DIRECTORY) && inode && !S_ISDIR(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)) { dput(res); res = ERR_PTR(-ENOTDIR); + } else if (inode && S_ISREG(inode->i_mode)) { + dput(res); + res = ERR_PTR(-EOPENSTALE); } } if (switched) {