07.08.2019 19:27, John Snow wrote: > > > On 8/6/19 12:19 PM, Vladimir Sementsov-Ogievskiy wrote: >> 06.08.2019 19:09, Max Reitz wrote: >>> On 06.08.19 17:26, Vladimir Sementsov-Ogievskiy wrote: >>>> hbitmap_reset has an unobvious property: it rounds requested region up. >>>> It may provoke bugs, like in recently fixed write-blocking mode of >>>> mirror: user calls reset on unaligned region, not keeping in mind that >>>> there are possible unrelated dirty bytes, covered by rounded-up region >>>> and information of this unrelated "dirtiness" will be lost. >>>> >>>> Make hbitmap_reset strict: assert that arguments are aligned, allowing >>>> only one exception when @start + @count == hb->orig_size. It's needed >>>> to comfort users of hbitmap_next_dirty_area, which cares about >>>> hb->orig_size. >>>> >>>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> >>>> --- >>>> >>>> v2 based on Max's https://github.com/XanClic/qemu.git block >>>> which will be merged soon to 4.1, and this patch goes to 4.2 >>>> Based-on: https://github.com/XanClic/qemu.git block >>>> >>>> v1 was "[PATCH] util/hbitmap: fix unaligned reset", and as I understand >>>> we all agreed to just assert alignment instead of aligning down >>>> automatically. >>>> >>>> include/qemu/hbitmap.h | 5 +++++ >>>> tests/test-hbitmap.c | 2 +- >>>> util/hbitmap.c | 4 ++++ >>>> 3 files changed, 10 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h >>>> index 4afbe6292e..7865e819ca 100644 >>>> --- a/include/qemu/hbitmap.h >>>> +++ b/include/qemu/hbitmap.h >>>> @@ -132,6 +132,11 @@ void hbitmap_set(HBitmap *hb, uint64_t start, >>>> uint64_t count); >>>> * @count: Number of bits to reset. >>>> * >>>> * Reset a consecutive range of bits in an HBitmap. >>>> + * @start and @count must be aligned to bitmap granularity. The only >>>> exception >>>> + * is resetting the tail of the bitmap: @count may be equal to @start + >>>> + * hb->orig_size, >>> >>> s/@start + hb->orig_size/hb->orig_size - @start/, I think. >> >> Ha, I wanted to say start + count equal to orig_size. Yours is OK too of >> course. >> >>> >>>> in this case @count may be not aligned. @start + @count >>> >>> +are >>> >>> With those fixed: >>> >>> Reviewed-by: Max Reitz <mre...@redhat.com> >> >> Thanks! >> > > I'll add this to the pile for 4.2, after I fix the rebase conflicts that > arose from 4.1-rc4. >
Hi! Didn't you forget, or should I resend? -- Best regards, Vladimir