2008/6/3 Bill Mccormick <[EMAIL PROTECTED]>: > A couple of my XOs are reporting what look like FS error messages on boot: > > [91.463670] JFFS2 notice: (664) check_node_data: wrong data CRC in data > node at 0x1ec215f0: read 0x3e7c7e03, calculated 0xf7e1d50c > ... > > is this a known problem?
According to Dave Woodhouse, who wrote JFFS2, these notices typically mean that at some point you've hard powered off, and as a result JFFS has some uncommitted data lying around on flash. It's almost always harmless, a part of the journal which was never committed: "either it was a new write which hadn't yet been synced, or it was a GC write which just doesn't achieve anything now." However, these messages *could* indicate an actual problem -- "we never came up with a good heuristic for when _not_ to complain". Woodhouse suggests that in the future "perhaps we should write a 'yes, I know there's a CRC failure' node _after_ the offending node, when we reboot and find it" since directly rewriting the node is not an option due to the mechanics of NAND flash; that would help confine these messages to immediately after a hard reboot. At present, you'll keep seeing a "bad CRC" message every time that particular JFFS node is accessed until it is eventually GC'ed. Anyone want to volunteer to turn the above into a FAQ which would be discoverable on our wiki, so that future wonderers don't have to pry the information from the head of dwmw2? --scott -- ( http://cscott.net/ ) _______________________________________________ Devel mailing list [email protected] http://lists.laptop.org/listinfo/devel
