What I forgot to mention: `uname -r`: 3.17.0-0.rc6.git2.1.fc22.x86_64 `btrfs --version`: Btrfs v3.16
regards, Niklas Am 01.10.2014 um 22:29 schrieb Niklas Fischer: > Hello, > > I was trying to determine how btrfs reacts to disk errors, when I > discovered, that flipping two Bytes, supposedly inside of a file can > render the filesystem unusable. Here is what I did: > > 1. dd if=/dev/zero of=/dev/sdg2 bs=1M > 2. mkfs.btrfs /dev/sdg2 > 3. mount /dev/sdg2 /tmp/btrfs > 4. echo "hello world this is some text" > /tmp/btrfs/hello > 5. umount /dev/sdg2 > > this should result in this image [1] > > in the following steps /dev/sdg2 is altered. Basically, we want to apply > s/world/wirld/g > > 6. dd if=/dev/sdg2 of=/tmp/sdg2 bs=1M > 7. edit /tmp/sdg2 in ghex, find & replace all occurences of "world" with > "wirld" (two occurences found), save as /tmp/sdg2_new > 8. dd if=/tmp/sdg2_new of=/dev/sdg2 bs=1M > > /dev/sdg2 now looks like this [2] > > now, when I try mounting /dev/sdg2: > > """22:21 root@localhost ~# > LANG=EN mount /dev/sdg2 /tmp/btrfs/ > mount: mount /dev/sdg2 on /tmp/btrfs failed: Cannot allocate memory""" > > ok, so let us try btrfs check > > """22:21 root@localhost ~# > LANG=EN btrfs check /dev/sdg2 > checksum verify failed on 4222976 found F22E71BD wanted CE334502 > checksum verify failed on 4222976 found F22E71BD wanted CE334502 > Csum didn't match > Checking filesystem on /dev/sdg2 > UUID: ea2843f1-e8aa-420f-acf8-6ef13f6c6753 > checking extents > Speicherzugriffsfehler (Speicherabzug geschrieben)""" > > that last line reads "Segfault, memory dumped". Is this behaviour expected? > > Kind regards, > Niklas > > [1] tgz: https://gigamove.rz.rwth-aachen.de/d/id/R5CKikxbYTBdqs > raw: https://gigamove.rz.rwth-aachen.de/d/id/VgMXAicS7CGEjt > [2] tgz: https://gigamove.rz.rwth-aachen.de/d/id/cEebNYne9ppFy4 > raw: https://gigamove.rz.rwth-aachen.de/d/id/ATJa7wpfEWdfL2 > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
