From: Gabriel Krisman Bertazi <krisman@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
lsf-pc <lsf-pc@lists.linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] tracing the source of errors
Date: Thu, 08 Feb 2024 15:39:09 -0500 [thread overview]
Message-ID: <875xyyvggi.fsf@mailhost.krisman.be> (raw)
In-Reply-To: <20240207110041.fwypjtzsgrcdhalv@quack3> (Jan Kara's message of "Wed, 7 Feb 2024 12:00:41 +0100")
Jan Kara <jack@suse.cz> writes:
> On Wed 07-02-24 10:54:34, Miklos Szeredi via Lsf-pc wrote:
>> [I'm not planning to attend LSF this year, but I thought this topic
>> might be of interest to those who will.]
>>
>> The errno thing is really ancient and yet quite usable. But when
>> trying to find out where a particular EINVAL is coming from, that's
>> often mission impossible.
>>
>> Would it make sense to add infrastructure to allow tracing the source
>> of errors? E.g.
>>
>> strace --errno-trace ls -l foo
>> ...
>> statx(AT_FDCWD, "foo", ...) = -1 ENOENT [fs/namei.c:1852]
>> ...
>>
>> Don't know about others, but this issue comes up quite often for me.
>
> Yes, having this available would be really useful at times. Sometimes I
> had to resort to kprobes or good old printks.
>
>> I would implement this with macros that record the place where a
>> particular error has originated, and some way to query the last one
>> (which wouldn't be 100% accurate, but good enough I guess).
>
> The problem always has been how to implement this functionality in a
> transparent way so the code does not become a mess. So if you have some
> idea, I'd say go for it :)
I had a proposal to provide the LoC of filesystem errors as part of an
extended record of the FAN_FS_ERROR messages (fanotify interface). It
might be a sensible interface to expose this information if not
prohibitively expensive.
One might record the position with a macro and do the fsnotify_sb_error
from a safer context.
--
Gabriel Krisman Bertazi
next prev parent reply other threads:[~2024-02-08 20:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-07 9:54 [LSF/MM/BPF TOPIC] tracing the source of errors Miklos Szeredi
2024-02-07 11:00 ` [Lsf-pc] " Jan Kara
2024-02-07 11:23 ` Miklos Szeredi
2024-02-07 12:00 ` Matthew Wilcox
2024-02-07 12:19 ` Miklos Szeredi
2024-02-08 20:47 ` Gabriel Krisman Bertazi
2024-02-07 19:29 ` Eric Sandeen
2024-02-08 20:39 ` Gabriel Krisman Bertazi [this message]
2024-02-07 17:16 ` Darrick J. Wong
2024-02-07 21:37 ` Dave Chinner
2024-02-08 9:09 ` Miklos Szeredi
2024-02-09 2:27 ` Dave Chinner
2024-02-08 15:57 ` Matthew Wilcox
2024-02-09 1:55 ` Dave Chinner
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