From: Amir Goldstein <amir73il@gmail.com>
Date: Sat, 8 Apr 2017 11:49:06 +0000 (+0300)
Subject: vfs: ftruncate check IS_APPEND() on real upper inode
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=78757af6518a35bdc22b4e7f660ff9dbbeba35d7;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

vfs: ftruncate check IS_APPEND() on real upper inode

ftruncate an overlayfs inode was checking IS_APPEND() on
overlay inode, but overlay inode does not have the S_APPEND flag.

Check IS_APPEND() on real upper inode instead.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---

diff --git a/fs/open.c b/fs/open.c
index 949cef29c3bb..993a91d20cc7 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -193,7 +193,8 @@ static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
 		goto out_putf;
 
 	error = -EPERM;
-	if (IS_APPEND(inode))
+	/* Check IS_APPEND on real upper inode */
+	if (IS_APPEND(file_inode(f.file)))
 		goto out_putf;
 
 	sb_start_write(inode->i_sb);