Subject: Re: UBC problems
To: Chuck Silvers <email@example.com>
From: Steven M. Bellovin <firstname.lastname@example.org>
Date: 01/15/2005 10:36:39
In message <20050115151907.GA9021@spathi.chuq.com>, Chuck Silvers writes:
>> -I now believe that the best way to deal with this would be to
>> have UBC reads just return zero filled pages if the file is
>> not backed with real data, and let upper layers (above the
>> trap handler) check whether the read is legal. Just commenting
>> out the range check in genfs_getpages() isn't enough,
>> unfortunately. That's a pretty complex matter...
>creating pages for offsets past EOF is to be avoided in general, since
>it's pretty nonsensical. I checked in a different fix for this issue,
I don't understand -- are you trying to bar files with holes in them?
That's been part of Unix since the beginning.
--Prof. Steven M. Bellovin, http://www.cs.columbia.edu/~smb