From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Thu, 6 Jan 2022 23:24:03 +0000 (-0500)
Subject: NFSv4: nfs_atomic_open() can race when looking up a non-regular file
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1751fc1db36f6f411709e143d5393f92d12137a9;p=linux.git

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 408c3bb549b1e..5df75ed092685 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1999,12 +1999,17 @@ no_open:
 		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) {