On Thu, Oct 12, 2017 at 02:09:21PM +1100, Neil Brown wrote:
> On Tue, Oct 10 2017, Shaohua Li wrote:
>
> > From: Shaohua Li <shli@xxxxxx>
> >
> > If PAGE_SIZE is bigger than 4k, we could read out of the disk boundary. Limit
> > the read size to the end of disk. Write path already has similar limitation.
> >
> > Fix: 8031c3ddc70a(md/bitmap: copy correct data for bitmap super)
> > Reported-by: Joshua Kinard <kumba@xxxxxxxxxx>
> > Tested-by: Joshua Kinard <kumba@xxxxxxxxxx>
> > Cc: Song Liu <songliubraving@xxxxxx>
> > Signed-off-by: Shaohua Li <shli@xxxxxx>
>
> Given that this bug was introduced by
> Commit: 8031c3ddc70a ("md/bitmap: copy correct data for bitmap super")
>
> and that patch is markted:
>
> Cc: stable@xxxxxxxxxxxxxxx (4.10+)
>
> I think this patch should be tagged "CC: stable" too.
I thought the Fix tag is enough, but I'll add the stable
> However ... that earlier patch looks strange to me.
> Why is it that "raid5 cache could write bitmap superblock before bitmap superblock is
> initialized." Can we just get raid5 cache *not* to write the bitmap
> superblock too early?
> I think that would better than breaking code that previously worked.
That's the log reply code, which must update superblock and hence bitmap
superblock, because reply happens very earlier. I agree the reply might still
have problem with bitmap. We'd better defer reply after the raid is fully
initialized. Song, any idea?
Thanks,
Shaohua
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