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 <ericvh@xxxxxxxxxx> > > 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!