On 29.01.24 10:49, David Howells wrote:
> Fix netfs_unbuffered_write_iter() to return immediately if
> generic_write_checks() returns 0, indicating there's nothing to write.
> Note that netfs_file_write_iter() already does this.
>
> Also, whilst we're at it, put in checks for the size being zero before we
> even take the locks. Note that generic_write_checks() can still reduce the
> size to zero, so we still need that check.
>
> Without this, a warning similar to the following is logged to dmesg:
>
> netfs: Zero-sized write [R=1b6da]
>
> and the syscall fails with EIO, e.g.:
>
> /sbin/ldconfig.real: Writing of cache extension data failed: Input/output error
>
> This can be reproduced on 9p by:
>
> xfs_io -f -c 'pwrite 0 0' /xfstest.test/foo
>
> Fixes: 153a9961b551 ("netfs: Implement unbuffered/DIO write support")
> Reported-by: Eric Van Hensbergen <[email protected]>
> Link: https://lore.kernel.org/r/ZbQUU6QKmIftKsmo@FV7GG9FTHL/
David, thx for fixing Eric's regression, which I'm tracking.
Christian, just wondering: that patch afaics is sitting in vfs.netfs for
about three weeks now -- is that intentional or did it maybe fell
through the cracks somehow?
> [...]
Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.
On Mon, Feb 19, 2024 at 09:38:33AM +0100, Linux regression tracking (Thorsten Leemhuis) wrote:
> On 29.01.24 10:49, David Howells wrote:
> > Fix netfs_unbuffered_write_iter() to return immediately if
> > generic_write_checks() returns 0, indicating there's nothing to write.
> > Note that netfs_file_write_iter() already does this.
> >
> > Also, whilst we're at it, put in checks for the size being zero before we
> > even take the locks. Note that generic_write_checks() can still reduce the
> > size to zero, so we still need that check.
> >
> > Without this, a warning similar to the following is logged to dmesg:
> >
> > netfs: Zero-sized write [R=1b6da]
> >
> > and the syscall fails with EIO, e.g.:
> >
> > /sbin/ldconfig.real: Writing of cache extension data failed: Input/output error
> >
> > This can be reproduced on 9p by:
> >
> > xfs_io -f -c 'pwrite 0 0' /xfstest.test/foo
> >
> > Fixes: 153a9961b551 ("netfs: Implement unbuffered/DIO write support")
> > Reported-by: Eric Van Hensbergen <[email protected]>
> > Link: https://lore.kernel.org/r/ZbQUU6QKmIftKsmo@FV7GG9FTHL/
>
> David, thx for fixing Eric's regression, which I'm tracking.
>
> Christian, just wondering: that patch afaics is sitting in vfs.netfs for
> about three weeks now -- is that intentional or did it maybe fell
> through the cracks somehow?
I've moved it to vfs.fixes now and will send later this week. Thanks for
the reminder!