[ 40/82] vfs: increment iversion when a file is truncated

Ben Hutchings
2012-06-08T05:16:49Z

From: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

commit 799243a389bde0de10fa21ca1ca453d2fe538b85 upstream.

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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/attr.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/fs/attr.c
+++ b/fs/attr.c
@@ -176,6 +176,11 @@
return -EPERM;
}

+ 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)) {
mode_t amode = attr->ia_mode;
/* Flag setting protected by i_mutex */