Re: posix_fallocate

[Jamie Lokier]

Ulrich Drepper wrote:
> 	int posix_fallocate (int fd, off_t offset, size_t len)
> 
> The purpose of the function is to allocate enough storage so that
> future writes to the file in the range [offset,offset+len] cannot fail
> because the storage device has no room.
> 
> I'm currently emulating this function in a ugly way in glibc: I write
> to every single block on the file.  But this is by far not the best
> way.  This function belongs into the kernel.

You could try using sendfile from /dev/zero -- that gives the kernel or
fs a chance to optimise that path in future.

-- Jamie