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: v3.18-rc2~25^2~12
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d6320cbfc92910a3e5f10c42d98c231c98db4f60;p=karo-tx-linux.git

ext4: fix mmap data corruption when blocksize < pagesize

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>
Cc: stable@vger.kernel.org
---

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d5dd7d46844e..091845298f48 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4514,8 +4514,12 @@ 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