/usr/bin/fallocate -v -d -l 2 myfile takes forever

[Mark Geisert]

On 1/28/2024 11:56 PM, Mark Geisert via Cygwin wrote:
> On 1/28/2024 10:44 PM, Cedric Blancher via Cygwin wrote:
>> Good morning!
>>
>> rm -f myfile
>> touch myfile
>> /usr/bin/fallocate -v -d -l myfile takes forever with latest Cygwin 3.5
>                               ^ length goes here, before filename
> 
> I believe you need to
>      chattr +S myfile
> after the 'touch' to make the file sparsifiable.
> 
> Also, I'm unsure if '-d' makes sense when initially allocating a sparse 
> file.  If I leave it off, fallocate does the right thing.
> 
> I'm separately investigating the 'takes forever' report.

It's taking forever because it's in an infinite loop looking for data 
followed by a hole, which is not present in a new file being created. 
This is due to the '-d' option being specified.  fallocate ought to 
diagnose this condition rather than looping forever, but here we are.

It's possible we have an old fallocate from an old util-linux package. 
I'll try to investigate this further when I have time.

..mark