Hi

Thanks for the analysis, unfortunately I get the same assert error
when I attempt to run the repair from the compiled source.

# ./work/builds/btrfs-progs/btrfsck
usage: btrfsck dev
Btrfs Btrfs v0.19

# ./work/builds/btrfs-progs/btrfsck --repair /dev/sda2
enabling repair mode
checking extents
leaf parent key incorrect 46329503744
bad block 46329503744
owner ref check failed [46329503744 4096]
repair deleting extent record: key 46329503744 168 4096
adding new tree backref on start 46329503744 len 4096 parent 256 root 256
repaired damaged extent references
checking fs roots
btrfsck: btrfsck.c:397: process_inode_item: Assertion `!(rec->ino !=
key->objectid || rec->refs > 1)' failed.
Aborted