Re: [PATCH v11 13/13] block: apply COR-filter to block-stream jobs

15.10.2020 20:16, Andrey Shinkevich wrote: > On 14.10.2020 19:24, Max Reitz wrote: >> On 12.10.20 19:43, Andrey Shinkevich wrote: > > [...] > >>> --- >>>   block/stream.c             | 93 >>> +++++++++++++++++++++++++++++----------------- >>>   tests/qemu-iotests/030     | 51 +++---------------------- >>>   tests/qemu-iotests/030.out |  4 +- >>>   tests/qemu-iotests/141.out |  2 +- >>>   tests/qemu-iotests/245     | 19 +++++++--- >>>   5 files changed, 81 insertions(+), 88 deletions(-) >> >> Looks like stream_run() could be a bit streamlined now (the allocation >> checking should be unnecessary, unconditionally calling >> stream_populate() should be sufficient), but not necessary now. >> > > That is what I had kept in my mind when I tackled this patch. But > there is an underwater reef to streamline. Namely, how the > block-stream job gets known about a long unallocated tail to exit the > loop earlier in the stream_run(). Shall we return the '-EOF' or > another error code from the cor_co_preadv_part() to be handled by the > stream_run()? Any other suggestions, if any, will be appreciated. Just calling read CHUNK by CHUNK may be less efficient than is_allocated()-driven loop: you may end up with splitting regions unaligned to CHUNK-granularity, which would not be splitted with is_allocated()-driven loop. Current loop allows chunks unaligned to CHUNK.

So, I think, it's better to keep is_allocated() logic as is for now.