Re: [PATCH 08/12] ext4: hold i_rwsem until AIO completes

Christoph Hellwig
2020-01-15T06:48:32Z

On Tue, Jan 14, 2020 at 04:50:23PM -0500, Theodore Y. Ts'o wrote:
> I note that you've dropped the inode_dio_wait() in ext4's ZERO_RANGE,
> COLLAPSE_RANGE, INSERT_RANGE, etc. We had added these to avoid
> problems when various fallocate operations which modify the inode's
> logical->physical block mapping racing with direct I/O (both reads or
> writes).
>
> I don't see a replacement protection in this patch series. How does
> are file systems supported to protect against such races?

By holding i_rwsem until the direct I/O operations are finished, and
not just until they are sumbitted.