[3.16.y-ckt extended stable] Patch "ext4: fix mmap data corruption when blocksize < pagesize" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Mon Nov 10 11:31:10 UTC 2014


This is a note to let you know that I have just added a patch titled

    ext4: fix mmap data corruption when blocksize < pagesize

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt1.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 6c49ff6fb47a841d5e017d33192f8116d8536297 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack at suse.cz>
Date: Wed, 1 Oct 2014 21:49:46 -0400
Subject: 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 at suse.cz>
Signed-off-by: Theodore Ts'o <tytso at mit.edu>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/ext4/inode.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e9c9b5bd906a..14f34b02dde5 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4654,8 +4654,12 @@ 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
--
2.1.0





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