I tried 3.0.1 today, which contains the commit Theodore suggested and was no longer able to reproduce the problem. So I think the corruption we have seen is indeed related to: commit 7132de744ba76930d13033061018ddd7e3e8cd91 Author: Maxim Patlasov <maxim.patlasov@xxxxxxxxx> Date: Sun Jul 10 19:37:48 2011 -0400 ext4: fix i_blocks/quota accounting when extent insertion fails I will now try to apply this patch to the RHEL6.1 kernel and see what happens... Thanks for your help. Christian 2011/8/3 Yehuda Sadeh Weinraub <yehuda.sadeh@xxxxxxxxxxxxx>: > On Wed, Aug 3, 2011 at 7:16 AM, Christian Brunner <chb@xxxxxx> wrote: > ... >> I tried to reproduce this without ceph, but wasn't able to... >> >> In the meantime it seams, that I can also see the side effects on the >> librbd side: I get an "librbd: data error!" when I do an "rbd copy". >> >> When I look at the librbd code this is related to a sparse_read not >> returning the right size of the object. >> >> I don't know if it helps, but I think that the problem is also related >> to sparse file usage. >> > > There were a few sparse-read issues that we fixed not too long ago, > but should have been fixed for at least the previous ceph version. I'm > not sure what version you're using. > There was a ext4 fiemap issue that I was hitting on specific > environments but couldn't determine whether it was fixed in later > kernel versions (I was using 2.6.32). Now is a good time to try and > get to the bottom of it. Here's a script I was using to reproduce it: > > #!/bin/sh > dd if=/dev/urandom of=bla bs=1 seek=$((0x6f000)) count=$((0x1000)); sync > dd if=/dev/urandom of=bla bs=1 seek=$((0x70000)) count=$((0x1000)); sync > dd if=/dev/urandom of=bla bs=1 seek=$((0x71000)) count=$((0x1000)); sync > dd if=/dev/urandom of=bla bs=1 seek=$((0x72000)) count=$((0x1000)); sync > dd if=/dev/urandom of=bla bs=1 seek=$((0x73000)) count=$((0x1000)); sync > dd if=/dev/urandom of=bla bs=1 seek=$((0x74000)) count=$((0x2000)); sync > dd if=/dev/urandom of=bla bs=1 seek=$((0x2ae000)) count=$((0x2000)); sync > > You can compile and run the following utility to dump all the extents: > http://pastebin.com/h2Cnpk2Q > > Thanks, > Yehuda > > Oh, btw, You can effectively disable the use of fiemap by setting the > 'filestore fiemap threshold' config option with large enough value > (e.g., anything bigger than 4 MB should be enough for rbd). > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
