Yaffs goes bad when flash is completelly full，yaffs文件系统在空间占满后，出现错误

yaffs2的文件系统，在文件空间占满后，如果依然不停的写文件，则会在一段时间后出现文件系统的错乱，文件名出现乱码的现象，日志可能出现yaffs tragedy: no more eraased blocks
!!!!!!!!! Allocator out !!!!!!!!!!!!!!!!!。Charles Manning已经fix这个问题在
http://www.aleph1.co.uk/cgi-bin/viewcvs.cgi/yaffs2/yaffs_guts.c?r1=1.85&r2=1.86。下面是邮件列表的相关信息。

 

From: Sharanu TURAMARI <[e-mail]>
Date: 2009/7/21
To: [e-mail]



Hi,
I am facing the problem with latest yaffs2 port when the whole flash space
is occupied.

I am following the below procedure:

- Copy the entire root contents to flash using "find bin boot dev etc home
init lib media sbin tmp usr var | cpio -pdum /flash" command
- Recursively copy the contents of flash to different directories in flash
using "cp -rf * sd0" etc until the flash usage gets 100% and the "
dev->nErasedBlocks" is 0.
- After sometimes I am getting "Allocator out " problems.
- Here onwards flash is completelly unusable since  even deletion fails and
only formatting will help.

Thoughts that come to mind is:
- Though nReservedBlocks  is 5 , why yaffs is using all the blocks and
getting dev->nErasedBlocks as 0.

- I am seeing yaffs_GarbageCollectBlock() is using one more fresh erased
block in the routine yaffs_WriteNewChunkWithTagsToNAND() it calls when it
is either a data chunk in live file or an Object header.
 So, instead of producing blocks it is consuming a block which explains
that whenever that condition occurs a block is being lost.

- Though the nReservedBlocks is 5 ,  I am not seeing any restrictions on
the block allocation if it reaches below 5.

- Just for experimentation , I hacked to use reserved blocks only
yaffs_GarbageCollectBlock()-> yaffs_WriteNewChunkWithTagsToNAND() , and
other allocations not use it. Thought there it is stopping
when dev->nErasedBlocks is 8 and no "Allocator out" problems, still flash
is unusable as not able to delete any file and increase free space usage.

- I am not seeing any erase problem since each  yaffs_GarbageCollectBlock()
is producing one erased block which is consumed immediately.

- If anybody has done the same experimentaion with yaffs ,please help me to
solve this.


Rgds,
Sharanu


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From: Charles Manning <[e-mail]>
Date: 2009/7/22
To: [e-mail]


I have been able to recreate this problem and am looking at it now.

Thanks to Sharanu for his persistence in pointing this out.

-- CHarles

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From: Charles Manning <[e-mail]>
Date: 2009/7/28
To: [e-mail]


Please try the latest cvs.

http://www.aleph1.co.uk/cgi-bin/viewcvs.cgi/yaffs2/yaffs_guts.c?r1=1.85&r2=1.86

-- CHarles

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From: Sharanu TURAMARI <[e-mail]>
Date: 2009/7/28
To: Charles Manning <[e-mail]>
Cc: [e-mail]



Hi Charles,
Applied the fix and everything is fine now.
Thanks for the quick and apt fix.

Rgds,
Sharanu