linux-kernel - Re: [PATCH v4 0/2] vfs: have syncfs() return error when there are writeback errors

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Message-ID: <a4415d7d5d75e6af4cb275f753068186342ef7be.camel@kernel.org>
Date:   Tue, 03 Mar 2020 08:10:19 -0500
From:   Jeff Layton <jlayton@...nel.org>
To:     viro@...iv.linux.org.uk, Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-api@...r.kernel.org, andres@...razel.de, willy@...radead.org,
        dhowells@...hat.com, hch@...radead.org, jack@...e.cz,
        david@...morbit.com, David Howells <dhowells@...hat.com>
Subject: Re: [PATCH v4 0/2] vfs: have syncfs() return error when there are
 writeback errors

On Thu, 2020-02-13 at 16:02 -0500, Jeff Layton wrote:
> v4:
> - switch to dedicated errseq_t cursor in struct file for syncfs
> - drop ioctl for fetching the errseq_t without syncing
> 
> This is the fourth posting of this patchset. After thinking about it
> more, I think multiplexing file->f_wb_err based on O_PATH open is just
> too weird. I think it'd be better if syncfs() "just worked" as expected
> no matter what sort of fd you use, or how you multiplex it with fsync.
> 
> Also (at least on x86_64) there is currently a 4 byte pad at the end of
> the struct so this doesn't end up growing the memory utilization anyway.
> Does anyone object to doing this?
> 
> I've also dropped the ioctl patch. I have a draft patch to expose that
> via fsinfo, but that functionality is really separate from returning an
> error to syncfs. We can look at that after the syncfs piece is settled.
> 
> Jeff Layton (2):
>   vfs: track per-sb writeback errors and report them to syncfs
>   buffer: record blockdev write errors in super_block that it backs
> 
>  drivers/dax/device.c    |  1 +
>  fs/buffer.c             |  2 ++
>  fs/file_table.c         |  1 +
>  fs/open.c               |  3 +--
>  fs/sync.c               |  6 ++++--
>  include/linux/fs.h      | 16 ++++++++++++++++
>  include/linux/pagemap.h |  5 ++++-
>  7 files changed, 29 insertions(+), 5 deletions(-)
> 

Hi Al,

Wondering if you've had a chance to look at these yet? I think it makes
sense -- the only part I'm not sure about is adding a field to struct
file. That ends up inside the 4-byte pad at the end on x86_64, so my
hope is that that's not a problem.

If you're too busy at the moment, then maybe Andrew can help shepherd
this in instead?

Thanks,
-- 
Jeff Layton <jlayton@...nel.org>