On Sat, Sep 1, 2012 at 8:41 AM, Michael <mike@xxxxxxxxxx> wrote: > Please make sure you are running a very recent kernel. Btrfs is VERY > active and fixes for things like this are going in all the time. Any > related crash errors, kernel oopses, and exact methodology so we can > reproduce would be useful. > dmesg and uname -a would help us triage this and see what we need to fix. > Mike I did save debug information like this, on a separate filesystem no less...unfortunately I was unable to sync and it disappeared when I was forced to cold boot. I don't have a spare machine available. To reproduce: 1. lvcreate vg --name lv --size 1G 2. mkbtrfs -M /dev/vg/lv 3. mkdir /mnt/test 4. mount /dev/vg/lv /mnt/test 5. dd bs=1024 count=1 < /dev/urandom > /tmp/foo 6. sha1sum /tmp/foo > /mnt/test/scrubme 7. sync (get /mnt/test/scrubme written to disk) 8. sed -e "s/the_sha1_sum/something_else_of_same_length/" < /dev/vg/lv > /dev/vg/lv 9. cat /mnt/test/scrubme (returns I/O error as expected, probably from a failed checksum) 9. btrfs scrub /mnt/test This is when all hell breaks loose. Will this be enough information to at least allow it to be reproduced or check if the bug still exists? > On Sat, Sep 1, 2012 at 3:10 AM, Shentino <shentino@xxxxxxxxx> wrote: >> >> Also, since the problem prevented me from syncing my other filesystmes >> I couldn't capture the debug info. >> >> It vanished during the cold boot still sitting in dirty page cache. >> >> On Fri, Aug 31, 2012 at 11:44 PM, Shentino <shentino@xxxxxxxxx> wrote: >> > How effective would it be to directly write to the underlying device >> > and then running tests to see if the corruption is properly detected? >> > >> > I just ran a fuzz test by syncing, and then manually corrupting a file >> > with the help of a surgical sed (yes, the before and after patterns >> > had fixed equal lengths). First I got an I/O error (expected), then I >> > ran scrub and got more problems (not ok), the system froze (not good), >> > a reboot failed to mount the system again (worse), and then the fsck >> > program dumped core. >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" 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-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
