Hello, I get corruption with btrfs in a loop device with linux-3.16.3 (https://git.kernel.org/cgit/linux/kernel/git/mason/linux-btrfs.git/ for-linus applied). I never had a problem with this setup until 3.16. This happened just after unpacking a few thousand small files and reading them back with an IDE (phpstorm). The loop file is a 50GB nocow file with LUKS on it. mount options for the main btrfs filesystem: /dev/sda2 on / type btrfs (rw,noatime,compress-force=lzo,ssd,discard,noacl,space_cache) mount options for the loop device: /dev/mapper/myvolume on /mnt/volume type btrfs (rw,noatime,compress-force=lzo,ssd,noacl,space_cache) btrfsck: Checking filesystem on /dev/mapper/npoa UUID: 3a869f74-2a05-4ea2-9950-a6be5e4a9691 checking extents checking free space cache checking fs roots checking csums checking root refs found 197030750 bytes used err is 0 total csum bytes: 1245628 total tree bytes: 133332992 total fs tree bytes: 127696896 total extent tree bytes: 3997696 btree space waste bytes: 22086930 file data blocks allocated: 1277382656 referenced 2252468224 Btrfs v0.20-rc1-592-ge11a9ae-dirty I also got a btrfs-image of the loop file system if needed. If more information's are needed to investigate the issue just ask. Kindly regards Jan Killius