On 11/12/2015 11:30 AM, Peter Lieven wrote:
> This series aims at avoiding a hanging main-loop if a vserver has a
> CDROM image mounted from a NFS share and that NFS share goes down.
> Typical situation is that users mount an CDROM ISO to install something
> and then forget to eject that CDROM afterwards.
> As a consequence this mounted CD is able to bring down the
> whole vserver if the backend NFS share is unreachable. This is bad
> especially if the CDROM itself is not needed anymore at this point.
>
> v3->v4: - Patch 1: remove buf argument for cd_read_sector{_sync}
> - Patch 1: fix iov_base offset for 2352 sector size
> - Patch 2: fix indent [Fam]
> - Patch 3: fix leaking of req->iov.iov_base [Fam]
>
> v2->v3: - adressed Stefans comments on Patch 1
> - added patches 2,4,5,6
> - avoided the term cancel in Patch 3. Added an iovec,
> added a BH [Stefan]
> v1->v2: - fix offset for 2352 byte sector size [Kevin]
> - use a sync request if we continue an elementary transfer.
> As John pointed out we enter a race condition between next
> IDE command and async transfer otherwise. This is sill not
> optimal, but it fixes the NFS down problems for all cases where
> the NFS server goes down while there is no PIO CD activity.
> Of course, it could still happen during a PIO transfer, but I
> expect this to be the unlikelier case.
> I spent some effort trying to read more sectors at once and
> avoiding continuation of elementary transfers, but with
> whatever I came up it was destroying migration between different
> Qemu versions. I have a quite hackish patch that works and
> should survive migration, but I am not happy with it. So I
> would like to start with this version as it is a big improvement
> already.
> - Dropped Patch 5 because it is upstream meanwhile.
>
> Peter Lieven (6):
> ide/atapi: make PIO read requests async
> block: add blk_abort_aio_request
> ide: add support for IDEBufferedRequest
> ide: orphan all buffered requests on DMA cancel
> ide: enable buffered requests for ATAPI devices
> ide: enable buffered requests for PIO read requests
>
> block/block-backend.c | 17 +++----
> hw/ide/atapi.c | 103
> +++++++++++++++++++++++++++++++++++------
> hw/ide/core.c | 51 +++++++++++++++++++-
> hw/ide/internal.h | 14 ++++++
> hw/ide/pci.c | 19 ++++++++
> include/sysemu/block-backend.h | 3 ++
> 6 files changed, 182 insertions(+), 25 deletions(-)
>
It looks sane to me:
Reviewed-by: John Snow <js...@redhat.com>
Fam, Stefan: Do you think this is still sane for 2.5? I am inclined to
get it in as a fix, especially since we've been bouncing it around for
so long.
--js
