Re: [RFC PATCH 0/3] Stop clearing uptodate flag on write IO error

From: Andrew Morton
Date: Thu Jan 05 2012 - 17:16:39 EST


On Thu, 5 Jan 2012 15:40:04 +0100
Jan Kara <jack@xxxxxxx> wrote:

>
> Hello,
>
> for mostly historical reasons we still clear buffer_uptodate flag on write
> IO errors.

I have long and strong memories of never being able to understand why
we did that.

> This is not only semantically wrong (buffer still has correct data
> in it) but it also triggers warnings in mark_buffer_dirty when buffer is
> written again which scares lots of users (as they tend to unplug USB sticks
> too early). This patch series is an attempt to start solving the problem
> by allowing filesystem to tell whether it wishes buffer_uptodate flag cleared
> on write IO error. Ext2 is converted to use this as an example. Eventually
> when all filesystems are converted, we can remove the condition.
>
> Do people think this is a desirable way to go?
>

Linus might have some thoughts.
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