tree 1be44adf3df6f32f8d13df54a0e68f7fd8b9ac26
parent 60d4616f3dc63371b3dc367e5e88fd4b4f037f65
author Dmitry Monakhov <dmonakhov@openvz.org> 1349845498 -0400
committer Theodore Ts'o <tytso@mit.edu> 1349845498 -0400

ext4: race-condition protection for ext4_convert_unwritten_extents_endio

We assumed that at the time we call ext4_convert_unwritten_extents_endio()
extent in question is fully inside [map.m_lblk, map->m_len] because
it was already split during submission.  But this may not be true due to
a race between writeback vs fallocate.

If extent in question is larger than requested we will split it again.
Special precautions should being done if zeroout required because
[map.m_lblk, map->m_len] already contains valid data.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org