From: Jan Kara <jack@suse.cz>
Date: Thu, 2 Oct 2014 01:49:46 +0000 (-0400)
Subject: ext4: fix mmap data corruption when blocksize < pagesize
X-Git-Tag: v3.17.3~168
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c8cdbdb2ac79a73d444b35d1d3b6291eb97c48db;p=thirdparty%2Fkernel%2Fstable.git

ext4: fix mmap data corruption when blocksize < pagesize

commit d6320cbfc92910a3e5f10c42d98c231c98db4f60 upstream.

Use truncate_isize_extended() when hole is being created in a file so that
->page_mkwrite() will get called for the partial tail page if it is
mmaped (see the first patch in the series for details).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3aa26e9117c44..9e269489e0948 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4536,8 +4536,12 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 				ext4_orphan_del(NULL, inode);
 				goto err_out;
 			}
-		} else
+		} else {
+			loff_t oldsize = inode->i_size;
+
 			i_size_write(inode, attr->ia_size);
+			pagecache_isize_extended(inode, oldsize, inode->i_size);
+		}
 
 		/*
 		 * Blocks are going to be removed from the inode. Wait