linux-ext4 - [PATCH 2/2] ext4: Fix mmap data corruption when blocksize

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Message-Id: <1411484603-17756-3-git-send-email-jack@suse.cz>
Date:	Tue, 23 Sep 2014 17:03:23 +0200
From:	Jan Kara <jack@...e.cz>
To:	linux-fsdevel@...r.kernel.org
Cc:	linux-mm@...ck.org, Dave Chinner <david@...morbit.com>,
	linux-ext4@...r.kernel.org, Ted Tso <tytso@....edu>,
	Jan Kara <jack@...e.cz>
Subject: [PATCH 2/2] ext4: Fix mmap data corruption when blocksize < pagesize

Use block_create_hole() 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@...e.cz>
---
 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 3aa26e9117c4..fdcb007c2c9e 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 old_size = inode->i_size;
+
 			i_size_write(inode, attr->ia_size);
+			block_create_hole(inode, old_size, inode->i_size);
+		}
 
 		/*
 		 * Blocks are going to be removed from the inode. Wait
-- 
1.8.1.4

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