Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751913Ab3JWNtk (ORCPT ); Wed, 23 Oct 2013 09:49:40 -0400 Received: from forward5h.mail.yandex.net ([84.201.186.23]:38090 "EHLO forward5h.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751111Ab3JWNtj (ORCPT ); Wed, 23 Oct 2013 09:49:39 -0400 X-Greylist: delayed 594 seconds by postgrey-1.27 at vger.kernel.org; Wed, 23 Oct 2013 09:49:38 EDT From: Konstantin Tokarev To: Brent Taylor Cc: "linux-mtd@lists.infradead.org" , Artem Bityutskiy , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" In-Reply-To: References: <55541379679397@web20h.yandex.ru> <183031382371160@web6m.yandex.ru> <139841382436609@web24g.yandex.ru> <300471382514034@web11h.yandex.ru> Subject: Re: lz4hc compression in UBIFS? MIME-Version: 1.0 Message-Id: <133391382535580@web11h.yandex.ru> X-Mailer: Yamail [ http://yandex.ru ] 5.0 Date: Wed, 23 Oct 2013 17:39:40 +0400 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=koi8-r Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2335 Lines: 62 23.10.2013, 16:49, "Brent Taylor" : > On Wed, Oct 23, 2013 at 2:40 AM, Konstantin Tokarev wrote: > >> ?23.10.2013, 09:26, "Brent Taylor" : >>> ?Konstantin, >>> ????I did my testing with data from /dev/urandom (which I now realize >>> ?wasn't the best choice of data source), but if I use /dev/zero (which >>> ?actually causes data compression to occur), the decompressor fails. ?I >>> ?don't know the internal workings of the lz4hc compressor or the lz4 >>> ?decompressor. ?I couldn't find any examples of any code in the kernel >>> ?actually using the compressor. ?I've cc'ed the maintainers of the >>> ?lz4hc_compress.c to see if they my have some more insight to the >>> ?issue. >> ?Does decompressor fail for you with the same error messages? >> >> ?Have you tried to copy my file to the volume? It looks like minimal test case >> ?for my board, if I remove any line decompressor works fine. >> >> ?-- >> ?Regards, >> ?Konstantin > > Yes, I get the same error, here's a dump from UBIFS when I cat a file > filled with data from /dev/zero: > > UBIFS error (pid 4288): ubifs_decompress: cannot decompress 12 bytes, > compressor lz4hc, error -22 > UBIFS error (pid 4288): read_block: bad data node (block 0, inode 71) > ????????magic ?????????0x6101831 > ????????crc ???????????0xff61a078 > ????????node_type ?????1 (data node) > ????????group_type ????0 (no node group) > ????????sqnum ?????????2700 > ????????len ???????????60 > ????????key ???????????(71, data, 0) > ????????size ??????????512 > ????????compr_typ ?????3 > ????????data size ?????12 > ????????data: > ????????00000000: 1f 00 01 00 ff e8 50 00 00 00 00 00 > UBIFS error (pid 4288): do_readpage: cannot read page 0 of inode 71, error -22 > cat: /opt/data/zero.bin: Input/output error > > Steps to reproduce are: > 1. ?Create a file with all zeros: dd if=/dev/zero bs=512 count=1 > of=/opt/data/zero.bin > 2. ?Unmount ubifs and detach ubi partition > 3. ?attach ubi partition and mount ubifs > 4. cat /opt/data/zero.bin Reproduced here. -- Regards, Konstantin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/