Revert "NFSv4: Handle the special Linux file open access mode"

BugLink: https://bugs.launchpad.net/bugs/1969107
[ Upstream commit ab0fc21bc7105b54bafd85bd8b82742f9e68898a ]

This reverts commit 44942b4e457beda00981f616402a1a791e8c616e.

After secondly opening a file with O_ACCMODE|O_DIRECT flags,
nfs4_valid_open_stateid() will dereference NULL nfs4_state when lseek().

Reproducer:
  1. mount -t nfs -o vers=4.2 $server_ip:/ /mnt/
  2. fd = open("/mnt/file", O_ACCMODE|O_DIRECT|O_CREAT)
  3. close(fd)
  4. fd = open("/mnt/file", O_ACCMODE|O_DIRECT)
  5. lseek(fd)

Reported-by: Lyu Tao <tao.lyu@epfl.ch>
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 9f0c217469e84e71f7423bce64527c0b56bf9228)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 410f87bc48cca6c9aed6e50274933a59e5b85f81..f4f75db7a82586c876a7806cae9187084f7e1be6 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1167,7 +1167,6 @@ int nfs_open(struct inode *inode, struct file *filp)
        nfs_fscache_open_file(inode, filp);
        return 0;
 }
-EXPORT_SYMBOL_GPL(nfs_open);
 
 /*
  * This function is called whenever some part of NFS notices that

diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index c91565227ea2ab372aae379939bd918999b75d75..8f35b5e13e93190af563d2549f3b21a1f393df62 100644 (file)
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -51,7 +51,7 @@ nfs4_file_open(struct inode *inode, struct file *filp)
                return err;
 
        if ((openflags & O_ACCMODE) == 3)
-               return nfs_open(inode, filp);
+               openflags--;
 
        /* We can't create new files here */
        openflags &= ~(O_CREAT|O_EXCL);