Subject: Re: kern/6652: swapping to a sparse file fails unpredictably.
To: Jason Thorpe <>
From: Marc Horowitz <>
List: netbsd-bugs
Date: 01/05/1999 16:53:13
Jason Thorpe <> writes:

>> I would say that any attempt to swapon to a sparse file should fail
>> with EINVAL.  Same goes for the vnd code.

Well, eventually, growing the file would be nice.  But this is a
reasonable start.

We discussed this on ICB a bit.  The only issue here is that it would
be nice if there was a non-O(n) way to determine if a file is sparse.
I'm not sure how to do this (or if it even makes sense) in a
filesystem generic way.  I think this might be possible using the
indirect block macros, but I'm not ffs-clueful enough to know the
details.  If you could give me some clue, or a pointer to it, I'll try
to fix it.