From: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Date: Thu, 25 Oct 2012 01:14:45 +0000 (+1100)
Subject: vfs: increment iversion when a file is truncated
X-Git-Tag: next-20121029~1^2~125
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=852f1b3591f5471f4bac1119e2326efd2642942d;p=karo-tx-linux.git

vfs: increment iversion when a file is truncated

When a file is truncated with truncate()/ftruncate() and then closed,
iversion is not updated.  This patch uses ATTR_SIZE flag as an indication
to increment iversion.

Mimi said:

On fput(), i_version is used to detect and flag files that have changed
and need to be re-measured in the IMA measurement policy.  When a file
is truncated with truncate()/ftruncate() and then closed, i_version is
not updated.  As a result, although the file has changed, it will not be
re-measured and added to the IMA measurement list on subsequent access.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/fs/attr.c b/fs/attr.c
index cce7df53b694..9689817dd26a 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -184,6 +184,11 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
 			inode_inc_iversion(inode);
 	}
 
+	if ((ia_valid & ATTR_SIZE) && IS_I_VERSION(inode)) {
+		if (attr->ia_size != inode->i_size)
+			inode_inc_iversion(inode);
+	}
+
 	if ((ia_valid & ATTR_MODE)) {
 		umode_t amode = attr->ia_mode;
 		/* Flag setting protected by i_mutex */