Messages in this thread | | | Date | Tue, 24 May 2011 09:33:52 +0200 | From | Michal Simek <> | Subject | Re: Unaligned jffs2 dnode address - tested by nandsim |
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Hi,
Any update on this? Does someone know if jffs dnode should be aligned or not? I have added some developers from mtd-utils.
I have also done test with the latest mtd-utils from git and there is still unaligned address.
Any suggestions?
Thanks, Michal
BTW: I have fixed problem with unaligned access in the kernel but I think the problem is mainly in fs generation.
Michal Simek wrote: > Hi, > > I have reached one problem with jffs2 fs ecc tested by nandsim on > Microblaze. > > I am getting the fault like this. > # md5sum /mnt/delete.png > uncorrectable error : > uncorrectable error : > uncorrectable error : > uncorrectable error : > uncorrectable error : > mtd->read(0xcda bytes from 0xc044) returned ECC error > Data CRC 3bcfd461 != calculated CRC e6038cde for node at 0000c000 > uncorrectable error : > uncorrectable error : > uncorrectable error : > uncorrectable error : > uncorrectable error : > mtd->read(0xcda bytes from 0xc044) returned ECC error > Data CRC 3bcfd461 != calculated CRC e6038cde for node at 0000c000 > > > The main problem is that there is one address with is not aligned which > caused that ecc counting uses wrong data. > > I also found in nand_ecc code that there is written > "It is assumed that the buffers are aligned." which is definitely wrong > for my case. I expect that it is 4B alignment. > > I generated jffs2 filesystem by the following command (mkfs.jffs2 > revision 1.60) > mkfs.jffs2 -n -b -e 16KiB -t -d <folder> -o test.jffs2 > > test.jffs2 is also attached. > > I use these command to mounted: > flash_eraseall /dev/mtd0 > nandwrite -p /dev/mtd0 /var/ftp/test.jffs2 > mount -t jffs2 mtd:"NAND simulator partition 0" /mnt > > After enable some jffs2 debug message I have got the log. > > [JFFS2 DBG] (74) jffs2_add_tn_to_tree: insert fragment 0x00-0x1000, ver > 1 at 00000900 > [JFFS2 DBG] (74) jffs2_lookup_tn: root c0c37df8, offset 0 > [JFFS2 DBG] (74) jffs2_add_tn_to_tree: 'this' found 0x1000-0x2000 (data) > [JFFS2 DBG] (74) jffs2_add_tn_to_tree: Ponder this ver 2, 0x1000-0x1000 > [JFFS2 DBG] (74) read_dnode: After adding ver 1: > [JFFS2 DBG] (74) read_dnode: c78432c0: v 1 r 0x0-0x1000 ov 0 > [JFFS2 DBG] (74) read_dnode: c78432e0: v 2 r 0x1000-0x2000 ov 0 > [JFFS2 DBG] (74) read_dnode: c7843300: v 3 r 0x2000-0x3000 ov 0 > [JFFS2 DBG] (74) read_dnode: c7843320: v 4 r 0x3000-0x364a ov 0 > [JFFS2 DBG] (74) read_dnode: c7843340: v 5 r 0x364a-0x4000 ov 0 > [JFFS2 DBG] (74) read_dnode: c7843360: v 6 r 0x4000-0x5000 ov 0 > [JFFS2 DBG] (74) read_dnode: c7843380: v 7 r 0x5000-0x6000 ov 0 > [JFFS2 DBG] (74) read_dnode: c78433a0: v 8 r 0x6000-0x7000 ov 0 > [JFFS2 DBG] (74) read_dnode: c78433c0: v 9 r 0x7000-0x7316 ov 0 > > > You see that tn->fn->ofs which is 0x364a which is not aligned. This > offset is causing > > I also tried to disable zlib compression which caused that map has > changed and it is aligned and there is no problem with ECC computing. > mkfs.jffs2 -n -b -e 16KiB -t -d <folder> -o test-nozlib.jffs2 -x zlib > > Have you ever seen this fault with alignment? > I think that the problem is with test.jffs2 generation. > Is there any option to setup that everything is aligned? > Or are you aware about any workaround how to prevent this fault? > > I do some testing directly on Microblaze. Generate random files and test > them and I haven't seen any problem when target read/write data from > jffs2 on nand with ecc. The problem is only with test.jffs2 generated on > host I see this fault. > > Thanks, > Michal >
-- Michal Simek, Ing. (M.Eng) PetaLogix - Linux Solutions for a Reconfigurable World w: www.petalogix.com p: +61-7-30090663,+42-0-721842854 f: +61-7-30090663
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