Re: [RFC] xfs: fake fallocate success for always CoW inodes

[Florian Weimer]

* Dave Chinner:

> I don't see how a glibc posix_fallocate() fallback that does a
> non-desctructive truncate up though some new interface is any better
> than just having the filesystem implement ALLOCATE_RANGE without the
> ENOSPC guarantees in the first place?

It's better because you don't have to get consensus among all file
system developers that implementing ALLOCATE_RANGE as a non-destructive
truncate is acceptable.  Even it means that future writes to the range
can fail with ENOSPC, contrary to what POSIX requires for
posix_fallocate.

Thanks,
Florian