Bug in 2.1 loop block dev?

Andrew McNamara (andrewm@connect.com.au)
Fri, 07 Aug 1998 21:55:42 +1000


I suspect there is a bug in the loopback blockdev - when a file is
released as a loop blockdev, the cached pages aren't invalidated.

This manifested itself when I was working on a filesystem module - I
was using the loopback dev to map an file containing an existing fs - I
switched between mounting an 800K floppy image to a 32M hard disk
image, but the superblock was still claiming to be only 800k.

This turned out to be duplicatable - any blocks read and still in the
cache would remain after the loop device was released then reconnected
to another file.

This was about 2.1.80 - I've been meaning to look further into the
problem since then, and hopefully post a fix, but I haven't had time.
With the approch of 2.2, I hope someone can take a quick look at this
and see if they also can duplicate it - there doesn't appear to be
a current maintainer.

---
Andrew McNamara (Senior System Administrator)

connect.com.au Pty Ltd
Lvl 3, 213 Miller St, North Sydney, NSW 2060, Australia
Phone: +61 2 9959 5959, Fax: +61 2 9966 1960

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