JFFS2 notice
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Home › Forums › MultiConnect OCG › JFFS2 notice
Tim Gunn.
Miguel ÁngelHi,
I found some warnings in /var/log/messages about the JFFS2. The message has the following format:
Jan 3 13:40:05 mtcdp user.notice kernel: JFFS2 notice: (1290) check_node_data: wrong data CRC in data node at 0x0501cf90: read 0xd711ac73, calculated 0x350a52d7
Is this a serious problem?
My hardware is MTCDP-H4-GP. Thanks
Tim GunnJFFS2 generates messages, is there a problem?
JFFS2 adopts the philosophy of keeping the user completely appraised of what is going on. This can catch out the unwary novice. The following messages can be moved to a higher log level once you are sure that they are benign.
Empty flash at 0xXXXXXXXX ends at 0xXXXXXXXX
This message is generated if a block of data is partially written. It is generally not a sign of any problem.
Name CRC failed on node at 0x00b620c8: Read 0x640c8ca3, calculated 0x795111fe
or similar message about CRC failures. If you have ever done unclean reboots – this is harmless. This just means that the unclean reboot happened (1) during data write or write buffer sync or (2) while GC was working or (3) while the write-buffer contained some data and was not yet synced before the unclean reboot happened. In them first and the third cases, you just lose the very last data you have written, in the second case you lose nothing. The wrong nodes will eventually be recycled by Garbage Collector and the messages will go (but they may live quite long).
But this also may mean that data on your flash was corrupted for sum reasons. Unfortunately JFFS2 cannot distinguish between node corruptions cause by unclean reboots and by real media corruptions. But the latter case is very rare.