Re: [PATCH] Revert "floppy: reintroduce O_NDELAY fix"

From: Jiri Kosina
Date: Mon Aug 16 2021 - 03:17:38 EST

On Sun, 8 Aug 2021, Denis Efremov wrote:

> The patch breaks userspace implementations (e.g. fdutils) and introduces
> regressions in behaviour. Previously, it was possible to O_NDELAY open a
> floppy device with no media inserted or with write protected media without
> an error. Some userspace tools use this particular behavior for probing.
> It's not the first time when we revert this patch. Previous revert is in
> commit f2791e7eadf4 (Revert "floppy: refactor open() flags handling").
> This reverts commit 8a0c014cd20516ade9654fc13b51345ec58e7be8.

By reverting it you bring back the bugs that were fixed by it -- e.g. the
possibility to livelock mmap() on the returned fd to keep waiting on the
page unlock bit forever, or the functionality bug reported at [1], and
likely others.


Jiri Kosina