On Tue, May 10, 2016 at 02:34:18PM -0600, Eric Blake wrote: > On 05/06/2016 02:45 AM, Quentin Casasnovas wrote: > > When running fstrim on a filesystem mounted through qemu-nbd with > > --discard=on, fstrim would fail with I/O errors: > > > > $ fstrim /k/spl/ice/ > > fstrim: /k/spl/ice/: FITRIM ioctl failed: Input/output error > > > > and qemu-nbd was spitting these: > > > > nbd.c:nbd_co_receive_request():L1232: len (94621696) is larger than max > > len (33554432) > > Your patch duplicates what is already present in qemu: > > commit eb38c3b67018ff8069e4f674a28661931a8a3e4f > Author: Paolo Bonzini <pbonz...@redhat.com> > Date: Thu Jan 7 14:32:42 2016 +0100 > > nbd-server: do not check request length except for reads and writes > > Only reads and writes need to allocate memory correspondent to the > request length. Other requests can be sent to the storage without > allocating any memory, and thus any request length is acceptable. > > Reported-by: Sitsofe Wheeler <sits...@yahoo.com> > Cc: qemu-bl...@nongnu.org > Reviewed-by: Max Reitz <mre...@redhat.com> > Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> > > For the purposes of qemu-stable, it's better to backport the existing > patch than to write a new version of it. >
Ha sorry I missed this! I wouldn't have tried to debug/fix myself otherwise :) > It also helps to state what version of qemu you were testing, as it is > obviously not the (soon-to-be-released) version 2.6 which already has > the fix. > I was using qemu-2.5.0-rc3 on Gentoo but this was also verified on some Debian systems which appears to be on 1.1.2+dfsg-6a+deb7u12 and on Ubuntu Xenial 2.0.0+dfsg-2ubuntu1.22. I wrote the patch on top of https://github.com/bonzini/qemu.git:master (a7e00e2) which didn't contain the fix last Friday. Anyway, cool if the fix is going into mainline :) Quentin
