Hi£¡
  thank you Charles! as you say, it due to spare/OOB area .
i eventually find that nand_read_oob( ) in nand_base.c frustrate me
for many days.it works well when insert a 3us delay in nand_read_oob( ):
--- nand_base.c.orig    2005-09-09 09:19:40.000000000 +0800
+++ nand_base.c 2005-09-09 08:52:04.000000000 +0800
@@ -1318,6 +1318,7 @@
        int     blockcheck = (1 << (this->phys_erase_shift - this->page_shift)) - 1;

        DEBUG (MTD_DEBUG_LEVEL3, "nand_read_oob: from = 0x%08x, len = %i\n", (unsigned int) from, (i
nt) len);
+       udelay(3);
        /* Shift to get page */
        page = (int)(from >> this->page_shift);
        chipnr = (int)(from >> this->chip_shift); 
	
======= 2005-09-09 06:05:20 Charles wrote£º=======
>Hi
>
>Lost data over an unmout/remout cycle is almost certainly due to an issue in 
>the spare/OOB area such that the placement being done by mtd is not what is 
>expected by yaffs.
>
>-- Charles
>
>
>On Tuesday 06 September 2005 18:39, Jian Zhang wrote:
>> hi,
>>  I use yaffs(the latest cvs from aleph1) on linux-2.4.21 with backported
>>  mtd(mtd20040705).there is no problem on the first mount.but it seems
>>  like lost data when i umount it then remount it.here is my log:
>>  1)reset and system run
>>  2)flash_eraseall /dev/mtd/0 &&insmod yaffs.o
>>  3)mount -t yaffs /dev/mtdblock/0 ./yaffs_mnt
>>  4)/yaffs/yaffs_mnt # cp /home/www/rtc_ds1337.o ./
>>  5)/yaffs/yaffs_mnt # ls -l
>>  drw-rw-rw-    1 root     root          512 Jan  1 04:23 lost+found
>>  -rw-r--r--    1 root     root        10745 Jan  1 04:22 rtc_ds1337.o
>>  6)/yaffs/yaffs_mnt # insmod rtc_ds1337.o
>>  Using rtc_ds1337.o
>>  7)/yaffs # umount yaffs_mnt/
>>  mtdblock_release
>>  ok
>>  8)/yaffs # mount -t yaffs /dev/mtdblock/0 ./yaffs_mnt/
>>  mtdblock_open
>>  ok
>>  yaffs: Attempting MTD mount on 31.0, "1f:00"
>>  9)/yaffs/yaffs_mnt # ls -l
>>  drw-rw-rw-    1 root     root          512 Jan  1 04:23 lost+found
>>  -rw-r--r--    1 root     root        10745 Jan  1 04:22 rtc_ds1337.o
>>  ***you will see the file size is the same as 5)
>>  10)/yaffs/yaffs_mnt # insmod rtc_ds1337.o
>>  Using rtc_ds1337.o
>>  pc : [<4014b5b4>]    lr : [<00043888>]    Not tainted
>>  sp : bfffd768  ip : bfffd7e4  fp : bfffd7e0
>>  r10: bfffd9f8  r9 : 00000009  r8 : 000a5df8
>>  r7 : 00000000  r6 : 001b63b8  r5 : 001b6f48  r4 : 001b6c48
>>  r3 : 00000000  r2 : 00000009  r1 : 000a5df8  r0 : 00000000
>>  Flags: nzCv  IRQs on  FIQs on  Mode USER_32  Segment user
>>  Control: C000717F  Table: 05F90000  DAC: 00000015
>>  Segmentation fault
>>
>>  i have do as this for times ,it has the same result! so i do consider
>>  it lose data when umount it.any body can give me some hints?
>>  thanks!
>>  JianZhang
>>_______________________________________________
>> yaffs mailing list
>> yaffs@stoneboat.aleph1.co.uk
>> http://stoneboat.aleph1.co.uk/cgi-bin/mailman/listinfo/yaffs
¡¡Jian Zhang
¡¡2005-09-09