#4184 BLOC First D: JFFS2 Dirent Anomaly

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#4184: JFFS2 Dirent Anomaly
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  Reporter:  wmb at firmworks.com  |       Owner:  dwmw2                 
      Type:  defect             |      Status:  new                   
  Priority:  blocker            |   Milestone:  First Deployment, V1.0
 Component:  kernel             |     Version:                        
Resolution:                     |    Keywords:                        
  Verified:  0                  |  
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Comment(by wmb at firmworks.com):

 Another example of this problem just surfaced, per the message below.  I
 gave him a special firmware with analysis tools, and we found 8,975,987
 duplicate dirents.  At least one of them was named "joydev.ko".

 scan-nand showed that the entire NAND was filled with JFFS2 blocks, except
 for two clean blocks.  The JFFS2 blocks all had summaries, except for one.

 By my calculations, a raw dirent + a summary dirent for "joydev.ko"
 consumes a total of 86 bytes, so the total space occupied by these dirents
 would be 771,934,882 bytes.

 Considering the size of the OS, this means that nearly everything other
 than the OS is filled with the junk dirents.

 {{{
 Yoshiki Ohshima wrote:
 >   Hello,
 >
 >   My B4 with 616 build went into some interesting state.  I was
 > copying some executable files to a directory (under /usr/local/lib/)
 > from my USB memory and playing with it (for several iteration) from
 > the Sugar console.  But I terminate the executable and left the system
 > idle for a night.  That was yesterday.
 >
 >   Today, I was trying to remove the file I copied by "rm" command but
 > get an error that says "No space left on device".  I try to reboot my
 > machine (perhaps a bad idea) but it went into the "launching X loop".
 >
 >   I did force poweroff and now the unit doesn't boot.  I got OFW's
 > "ok" prompt and typed:
 >
 >       dir nand:\boot
 >
 > but it says:
 >
 >         jffs2-file-system
 >         jffs2:bad read
 >
 > I saw some trac items about nand corruption and it might have happened
 > to me.  I don't know if there is a way to salvage some useful
 > information from my unit at this point, but if somebody has an idea
 > (or just say it is a known problem) please let me know.  Otherwise,
 > I'd just reinstall a build...
 >
 > -- Yoshiki
 }}}

-- 
Ticket URL: <https://dev.laptop.org/ticket/4184#comment:4>
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