My COW is too big!

Dec 19 22:19:38 VMRocky kernel: [31382.346361] datto: cow file ‘/.datto_5c24d097677d50a24ddec05cfa88367dc656b24ee1a208ee’ max size exceeded (4074979328/4074976051): -27

[31429.277961] EXT4-fs error (device dm-0): __ext4_get_inode_loc:4072: inode #264861: block 1048777: comm PipeFile: stdou: unable to read itable block

2016-12-19 22:25:56: ERROR: Error getting complete file “BAIiEKD6GCt5stoLw66E|root/usr/share/vim/vimfiles/syntax/poppler.vim” from VMRocky. Errorcode: READ_ERROR (12)

2016-12-19 22:25:46: FileSrv: Mapped name: /mnt/urbackup_snaps/5c24d097677d50a24ddec05cfa88367dc656b24ee1a208ee/usr/share/vim/vimfiles/syntax/poppler.vim
2016-12-19 22:25:46: FileSrv: Error: Reading from file failed. Errno: 5

I can’t specify a bigger max COW size as that’s already the max supported by dattobd, but really there’s something wrong when the COW grows to over 4GB on a filesystem where nothing is being written.

Anyway, this probably isn’t your bug, it’s dattobd’s.