ext4: don't take the i_mutex lock when doing DIO overwrites
Aligned and overwrite direct I/O can be parallelized. In
ext4_file_dio_write, we first check whether these conditions are
satisfied or not. If so, we take i_data_sem and release i_mutex lock
directly. Meanwhile iocb->private is set to indicate that this is a
dio overwrite, and it will be handled in ext4_ext_direct_IO.
[ Added fix from Dan Carpenter to fix locking bug on the error path. ]
CC: Tao Ma <tm@tao.ma>
CC: Eric Sandeen <sandeen@redhat.com>
CC: Robin Dong <hao.bigrat@gmail.com>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
2 files changed