Re: I/O errors without erros from underlying device

[Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>]

On Monday 07 of December 2015, John Stoffel wrote:
> Arkadiusz> 4.3.0 kernel, raid6 array:
> 
> I think there's a bug in the 4.3.x and 4.4-rc3 and lower with block
> merges.  I ran into these over the weekend, where v4.2.6 was stable,
> but anything higher would lock up and crash on me.

Well, no crashes here.

> So first step would be to make sure you get and test v4.4-rc4.

Do you know which commit there?

> 
> Arkadiusz> md7 : active raid6 sdg[10] sdad1[9] sdac1[8] sdag1[7] sdaf1[6]
> sdae1[5] sdaj1[4] sdai1[3] sdah1[2] sdn1[1] Arkadiusz>       31255089152
> blocks super 1.2 level 6, 512k chunk, algorithm 2 [10/10] [UUUUUUUUUU]
> Arkadiusz>       bitmap: 1/30 pages [4KB], 65536KB chunk
> 
> Arkadiusz> array had weird failure where many disks went into failed state
> but Arkadiusz> remove && adding these disks "fixed" it (turns out not
> really fixed it).
> 
> Arkadiusz> Unfortunately now some reads fail:
> 
> Arkadiusz> pread(4, 0x1483a00, 4096, 16003680464896) = -1 EIO (Input/output
> error)
> 
> Arkadiusz> To reproduce used xfs_io
> Arkadiusz>  xfs_io -d -c "pread 16003680464896 4096" /dev/md7
> Arkadiusz> pread64: Input/output error
> Arkadiusz> which does pread exactly as shown above.
> 
> Arkadiusz> write also fails for that area:
> Arkadiusz> xfs_io -d -c "pwrite 16003680464896 4096" /dev/md7
> Arkadiusz> pwrite64: Input/output error
> 
> Arkadiusz> Note that nothing is written in dmesg when that happens.
> 
> Arkadiusz> I've tried various offsets and sizes of pread and at some point
> that was logged: Arkadiusz> [  848.988518] Buffer I/O error on dev md7,
> logical block 3907148544, async page read
> 
> Arkadiusz> but no error from underlying devices.
> 
> Arkadiusz> List of bad blocks:
> Arkadiusz> http://sprunge.us/XSWI
> 
> Arkadiusz> What can I do now?
> 
> Arkadiusz> (loosing data from that few sectors is acceptable if the rest
> will be readable)
> 
> Arkadiusz> Thanks,
> Arkadiusz> --
> Arkadiusz> Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )
> Arkadiusz> --
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-- 
Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )
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