Rafał,
----- Ursprüngliche Mail -----
> Von: "Rafał Miłecki" <[email protected]>
> An: "Amir Goldstein" <[email protected]>, "Miklos Szeredi"
> <[email protected]>, [email protected],
> [email protected], "richard" <[email protected]>, "Artem Bityutskiy"
> <[email protected]>, "Adrian Hunter"
> <[email protected]>, [email protected], "Russell Senior"
> <[email protected]>, "OpenWrt
> Development List" <[email protected]>
> Gesendet: Freitag, 19. Oktober 2018 14:31:29
> Betreff: Regression in handling power cuts since 3a1e819b4e80 ("ovl: store
> file handle of lower inode on copy up")
> Hi,
>
> Since OpenWrt switch from kernel 4.9 to 4.14 users started randomly
> reporting file system corruptions. OpenWrt uses overlay(fs) with
> squashfs as lowerdir and ubifs as upperdir. Russell managed to isolate
> & describe test case for reproducing corruption when doing a power cut
> after first boot.
>
> Interestingly it cannot be reproduced on all devices (NAND dependant?
> arch dependant?!). I couldn't reproduce that problem on none of my
> Broadcom devices (ARM=y ARCH_BCM_5301X=y) so I had to buy Ubiquiti
> EdgeRouter X (ER-X) (MIPS=y RALINK=y). I reproduced it then and
> bisected down to the commit 3a1e819b4e80 ("ovl: store file handle of
> lower inode on copy up").
>
> FWIW I was told it also affects:
> Asus RT-AC58U (ARCH_IPQ40XX=y)
> powerpc
> RB493G, DIR-860L (ATH79=y)
>
> Steps to reproduce the problem:
> 1) Flash firmware
> 2) Boot (for the first time)
> 3) Let the init script copy config files from lowerdir to the upperdir
> 4) Wait for boot to finish
> 5) Verify content of some unmodified config on overlay, using either:
> hexdump -C /etc/config/dropbear
> hexdump -C /overlay/upper/etc/config/dropbear
> 6) Power cut & boot again
> 7) Check the content of the same file
Do you have something also I can test?
A C reproducer? An xfstest case?
> After above regressing commit the later check confirms the file size
> looks correct but it's filled with all 00-es only.
>
> Can I ask you to check if there is something possibly wrong with the
> above ovl commit? Or does it expose some problem with the ubifs? Or
> maybe the whole UBI?
Well, I fear it uncovers a problem in UBIFS. We had already problems with
overlayfs.
Did you bisect the problem and you are sure that the said commit is the first
bad commit?
> FWIW testing above commit (and one before it) always results in single
> error in the kernel log:
> [ 14.250184] UBIFS error (ubi0:1 pid 637): ubifs_add_orphan: orphaned twice
Please show the full log.
The orphan thing rings a bell, we had such a bug already.
Thanks,
//richard
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