=== Terminal output ===
# mount -o recovery /dev/md0 /mnt/root
mount: wrong fs type, bad option, bad superblock on /dev/md0,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so# dmesg | tail [58290.395538] device label root devid 1 transid 250160 /dev/md0 [58290.395891] btrfs: enabling auto recovery [58290.395895] btrfs: disk space caching is enabled [58290.396388] btrfs bad tree block start 0 139264 [58290.396401] btrfs: failed to read chunk root on md0 [58290.396660] btrfs: open_ctree failed # btrfsck /dev/md0 Check tree block failed, want=139264, have=0 Check tree block failed, want=139264, have=0 Check tree block failed, want=139264, have=0 read block failed check_tree_block Couldn't read chunk root Segmentation fault ======================= I'm having some problems with my btrfs partition. It showed up around the same time a disk got ejected from a RAID5 mdadm array, so the two are probably related. The array seems to be working properly now (or thinks it is), having rebuilt itself and completed a full integrity check However, the array lists 1196 events and found 180156080 mismatches on the integrity check, so it may be serious issues with my old disks from a Sun array. Even if my data is completely ruined (e.g. `dd if=/dev/urandom of=/dev/md0`), btrfsck should not segfault. Running `btrfs-show-super -a /dev/md0` appears to work fine, except "chunk_root_generation" is 12 lower than "generation" and "dev_item.generation" is 0, but I'm not sure how significant that is. I'm running 64-bit Linux Mint 14 KDE (Ubuntu 12.10 based), upgraded to the 3.9-rc1 kernel and latest git pull of the official btrfs-progs as of March 13, 2013. It uses gcc 4.7.2 (Ubuntu/Linaro 4.7.2-2ubuntu1). I have attached my backtrace (with commands I used to generate it). I could not find a debug version of libuuid to show where that is crashing. P.S. Is there any hope for my data? I have at least 1 small subvolume I'd really like to recover. Most of the rest is either backed up, copies of media, or stuff I can download. If it's all gone, I need to move on with rebuilding, so I can get back to my normal work environment. P.P.S. Sorry if anyone is getting this twice. The first message (with a core dump included) did not get a reply, nor was it on the mailing list archive.
backtrace
Description: Binary data
