tree 6926354a2c6cc8e5f0e930845774ffe73d3766b8
parent 24b584240a0006ea7436cd35f5e8983eb76f1e6f
author Jan Kara <jack@suse.cz> 1260325473 -0500
committer Theodore Ts'o <tytso@mit.edu> 1260325473 -0500

ext4: Avoid data / filesystem corruption when write fails to copy data

When ext4_write_begin fails after allocating some blocks or
generic_perform_write fails to copy data to write, we truncate blocks
already instantiated beyond i_size.  Although these blocks were never
inside i_size, we have to truncate the pagecache of these blocks so
that corresponding buffers get unmapped.  Otherwise subsequent
__block_prepare_write (called because we are retrying the write) will
find the buffers mapped, not call ->get_block, and thus the page will
be backed by already freed blocks leading to filesystem and data
corruption.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>