Can't mount: open_ctree failed!

[Florian Lindner <mailinglists@xgm.de>]

Hello,

all after sudden I can't mount my btrfs home partition anymore. System is 
Arch with kernel 3.17.2, but I use snapper which does snapshopts regularly 
and I had 3.17.1 before, which afaik had some problems with snapshops.

Trying to mount without any options gives to the syslog:

Nov 02 16:04:16 horus kernel: BTRFS: mismatching generation and 
generation_v2 found in root item. This root was probably mounted with an 
older kernel. Resetting all new fields.
Nov 02 16:04:16 horus kernel: parent transid verify failed on 2121534193664 
wanted 1073784832 found 45541
Nov 02 16:04:16 horus kernel: parent transid verify failed on 2121534193664 
wanted 1073784832 found 45541
Nov 02 16:04:16 horus kernel: BTRFS: open_ctree failed

btrfsck quits after about half a minute with

# btrfsck /dev/sdb1
root item for root 3377, current bytenr 2122078191616, current gen 
8589934592, current level 64, new bytenr 2122078191616, new gen 49443, new 
level 1
root 3377 has a root item with a more recent gen (8589934592) compared to 
the found root node (49443)

I also tried -s 0 or -s 1 or -b options to btrfsck, as well as

# btrfsck --init-extent-tree /dev/sdb1
root 3377 has a root item with a more recent gen (8589934592) compared to 
the found root node (49443)

# btrfsck --init-csum-tree /dev/sdb1
Creating a new CRC tree
root 3377 has a root item with a more recent gen (8589934592) compared to 
the found root node (49443)


Mounting with -o recovery gives exact the same error. My usual mount options 
were defaults,compress=lzo,subvol=__current.

I also tried btrfs-zero-log but this does not change anything either.

Any ideas are deeply appreciated! Please help!

Florian