On 11/11/16 00:10, Eric Blake wrote: > Peter reported a mild regression in qemu 2.7 when targetting the > Dell Equallogic iSCSI, which advertizes a preferred and maximum > unmap alignment at 15M. In qemu 2.6, trims not aligned to those > boundaries still made it to the device, but in 2.7, the block > layer is ignoring unaligned portions of guest requests, resulting > in fewer blocks being actually trimmed. > > Since discard is advisary,
advisory? > it is borderline if this counts as a > bug fix worthy for inclusion in 2.8, or if it should be deferred > to 2.9. At any rate, while I was able to test that the patch > didn't misbehave for me when I tweaked an NBD setup to force > 15M alignment, I am unable to test that it makes an actual > difference for Peter's hardware, and that needs to happen before > anyone even thinks of applying this. > > Eric Blake (2): > block: Return -ENOTSUP rather than assert on unaligned discards > block: Pass unaligned discard requests to drivers > > block/io.c | 36 +++++++++++++++++++++++------------- > block/iscsi.c | 4 +++- > block/qcow2.c | 4 ++++ > block/sheepdog.c | 5 +++-- > 4 files changed, 33 insertions(+), 16 deletions(-) >
