Messages in this thread | | | From | Johannes Hirte <> | Subject | Re: csum errors | Date | Thu, 15 Jul 2010 22:00:24 +0200 |
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Am Donnerstag 15 Juli 2010, 21:35:51 schrieb Chris Mason: > On Thu, Jul 15, 2010 at 09:32:12PM +0200, Johannes Hirte wrote: > > Am Donnerstag 15 Juli 2010, 21:03:09 schrieb Chris Mason: > > > On Thu, Jul 15, 2010 at 08:30:17PM +0200, Johannes Hirte wrote: > > > > Am Dienstag 13 Juli 2010, 14:23:58 schrieb Johannes Hirte: > > > > > ino 1959333 off 898342912 csum 4271223884 private 4271223883 > > > > > > > > I think, this is a different error. I've only seen them on > > > > filesystems from my Opteron system. It seems that the recorded csums > > > > are wrong and it looks to me like rounding errors. The data itself > > > > should be correct, as I've tested one affected file via md5sum > > > > against the original on another filesystem. Any ideas what is going > > > > wrong here? > > > > > > Are you doing data mirroring? > > > > No, I don't. > > > > > We can map that block and do a raw read off the device to see what the > > > data blocks actually contain. > > > > I've modified the btrfs-source a little to get the data. In inode.c I've > > > changed the code to: > Great. The bad csums are all just one bit off, that can't be an > accident. When were they written (which kernel?). Did you boot a 32 > bit kernel on there at any time?
No, I don't have a bootable 32bit installation on this system. I've tested it now with a 32bit system by dumping the whole filesystem to an external drive and mounting this to a 32bit system. The result was the same.
The affected files were written by different kernels. I think at least 2.6.34, 2.6.35-rc3 and 2.6.35-rc4 should be involved, perhaps 2.6.33 too. I'll try to figure it out more exactly.
regards, Johannes
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