[PATCH] fs: remove power of 2 and length boundary atomic write restrictions

[Vitaliy Filippov]

> If a user follows the current rules, they will not get a write which
> spans multiple extents and hence no -EINVAL. That is how it works for
> ext4, anyway.

What if he makes a sparse file by writing at random 64 kb aligned
offsets and then trying to overwrite 128 KB atomically? He'll still
get EINVAL as I understand.