Hi Guanghao
Thanks for your patch.
On Tue, Mar 4, 2025 at 8:27 PM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> 在 2025/03/04 14:12, Wu Guanghao 写道:
> > When testing the raid1, I found that adding disk to raid1 fails.
> > Here's how to reproduce it:
> >
> > 1. modprobe brd rd_nr=3 rd_size=524288
> > 2. mdadm -Cv /dev/md0 -l1 -n2 -e1.0 /dev/ram0 /dev/ram1
> >
> > 3. mdadm /dev/md0 -f /dev/ram0
> > 4. mdadm /dev/md0 -r /dev/ram0
> >
> > 5. echo "10000 100" > /sys/block/md0/md/dev-ram1/bad_blocks
> > 6. echo "write_error" > /sys/block/md0/md/dev-ram1/state
> >
> > 7. mkfs.xfs /dev/md0
Do we need this step7 here?
> > 8. mdadm --examine-badblocks /dev/ram1 # Bad block records can be seen
> > Bad-blocks on /dev/ram1:
> > 10000 for 100 sectors
> >
> > 9. mdadm /dev/md0 -a /dev/ram2
> > mdadm: add new device failed for /dev/ram2 as 2: Invalid argument
>
> Can you add a new regression test as well?
>
> >
> > When adding a disk to a RAID1 array, the metadata is read from the existing
> > member disks for synchronization. However, only the bad_blocks flag are copied,
> > the bad_blocks records are not copied, so the bad_blocks records are all zeros.
> > The kernel function super_1_load() detects bad_blocks flag and reads the
> > bad_blocks record, then sets the bad block using badblocks_set().
> >
> > After the kernel commit 1726c7746("badblocks: improve badblocks_set() for
> > multiple ranges handling"), if the length of a bad_blocks record is 0, it will
> > return a failure. Therefore the device addition will fail.
Can you give the specific function replace with "it will return a failure" here?
> >
> > So, don't set the bad_blocks flag when initializing the metadata, kernel can
> > handle it.
> >
> > Signed-off-by: Wu Guanghao <wuguanghao3@xxxxxxxxxx>
> > ---
> > super1.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/super1.c b/super1.c
> > index fe3c4c64..03578e5b 100644
> > --- a/super1.c
> > +++ b/super1.c
> > @@ -2139,6 +2139,9 @@ static int write_init_super1(struct supertype *st)
> > if (raid0_need_layout)
> > sb->feature_map |= __cpu_to_le32(MD_FEATURE_RAID0_LAYOUT);
> >
> > + if (sb->feature_map & MD_FEATURE_BAD_BLOCKS)
> > + sb->feature_map &= ~__cpu_to_le32(MD_FEATURE_BAD_BLOCKS);
>
> There are also other flags that is per rdev, like MD_FEATURE_REPLACEMENT
> and MD_FEATURE_JOURNAL, they should be excluded as well.
Hmm, why do we need to remove these flags too? It's better to use a
separate patch rather than using this patch and describe it in detail.
It's better to give an example also.
Best Regards
Xiao
>
> Thanks,
> Kuai
>
> > +
> > sb->sb_csum = calc_sb_1_csum(sb);
> > rv = store_super1(st, di->fd);
> >
>
>
