Re: [PATCH] Check for Null return of function of affs_bread in function affs_truncate

From: Nick Krause
Date: Fri Jun 20 2014 - 22:55:15 EST


Fair enough if somebody is running this file system I would be
happy to have someone test my code in order to fix this.
Cheers Nick

On Fri, Jun 20, 2014 at 10:38 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 20 Jun 2014 22:25:47 -0400 Nick Krause <xerofoify@xxxxxxxxx> wrote:
>
>> If you have any ideas about what is better
>> please let me known.
>
> I think the proposed patch was not a good one - it will cause truncate
> to silently return, probably leaving the fs in an inconsistent state.
> Neither the user nor the running application know this happened so they
> will just keep on modifying the filesystem, possibly mangling it
> further.
>
> The code as it stands at present is better - if bread() fails we'll get
> a nice solid oops and the current app will be terminated (at least).
> As we're in truncate it's quite possible that the entire fs will get
> wedged up due to now-permanently-held i_mutex, which is even better.
>
>
> As for the best fix, umm, hard. We're pretty screwed if we cannot read
> that block at this code site. Perhaps emit loud printks, forcibly turn
> the fs read-only then return -EIO/-ENOMEM/etc from the truncate. Such
> a change would require runtime testing, with some form of developer fault
> injection.
>
>
>
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