lz4hc compression in UBIFS?
Konstantin Tokarev
annulen at yandex.ru
Tue Oct 22 03:10:09 PDT 2013
22.10.2013, 07:43, "Brent Taylor" <motobud at gmail.com>:
> On Mon, Oct 21, 2013 at 10:59 AM, Konstantin Tokarev <annulen at yandex.ru> wrote:
>
>> 04.10.2013, 07:09, "Brent Taylor" <motobud at gmail.com>:
>>> Here is a patch based on linux-3.12-rc3. I haven't performed any
>>> performance testing UBIFS using lz4hc, but I can mount UBIFS volumes
>>> and haven't seen any problems yet. The only think I know that isn't
>>> correct about the patch is the description for the Kconfig element for
>>> select lz4hc as a compression option. I only copied the description
>>> from the lzo description.
>> Hi Brent,
>>
>> I'm testing your patch on my SH4 device. When I create new partition
>> with lz4hc compressor, it works fine: I can copy file into it, and
>> md5sums of original and copy match. However, after reboot I cannot
>> read the file anymore:
>>
>> UBIFS error (pid 1101): ubifs_decompress: cannot decompress 934 bytes, compressor lz4hc, error -22
>> UBIFS error (pid 1101): read_block: bad data node (block 1, inode 65)
>> UBIFS error (pid 1101): do_readpage: cannot read page 1 of inode 65, error -22
>>
>> The same error appears if I use lz4hc-compressed ubifs image to flash rootfs
>> (using patched mkfs.ubifs).
>>
>> Decompression error occurs in lz4_uncompress() function (lib/lz4/lz4_decompress.c),
>> on the line 101:
>>
>> /* Error: offset create reference outside destination buffer */
>> if (unlikely(ref < (BYTE *const) dest))
>> goto _output_error;
>>
>> Brent: are you able to read data from lz4hc volume on your device?
>> Anyone: any ideas what may happen here?
>>
>> --
>> Regards,
>> Konstantin
>
> Konstantin,
> I haven't seen anything like that on my at91sam9m10g45-ek
> development board. I haven't used a flash image from mkfs.ubifs yet.
> Is it possible the file system was not umounted cleanly before the
> reboot and UBIFS went through a recovery procedure? Maybe something
> breaks with lz4hc when UBIFS does a recovery? That's just a guess.
Could you save attached file on lz4hc volume, umount it and mount again?
I get aforementioned error when doing `cat set11.cfg`
--
Regards,
Konstantin
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