[PATCH 3.17 153/319] ext4: fix mmap data corruption when blocksize < pagesize

[Greg Kroah-Hartman]

3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@xxxxxxx>

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@xxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/ext4/inode.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4536,8 +4536,12 @@ int ext4_setattr(struct dentry *dentry,
 				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


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