send ioctl failed errno:2 (No such file or directory) about snapper

[aschnell]

Snapper compares the pre and post snapshots. For btrfs, it tries to use special code using the btrfs send/receive ioctl. That ioctl fails, likely not included in your kernel. Snapper then falls back to the general snapshot comparison code so there is no difference besides of speed. On a SSD the speedup would likely be small anyway.

[saamalik]

Just out of curiousity.

Where can I get the btrfs IOCTL kernel patch?

[aschnell]

It was included upstream about a year ago.

[saamalik]

Hmm -- I'm using a very recent stock mainline kernel:

Linux Vaio-Saad 3.12.6-1-ARCH #1

What is the config name?

[aschnell]

AFAIS there's no kernel config switch for btrfs send/receive. You can try to use the "send" command of the "btrfs" command line tool to see whether the ioctl works.

[oniko]

Unfortunately that's not the case (missing support in kernel). I bumped into same issue this week as well and I think missing support for ioctl would return ENOTTY from kernel. "btrfs send" using btrfs-progs works as expected but snapper keeps failing. I'll track it down and provide some further info hopefully...

[saamalik]

I have a feeling this issue is related to: https://www.mail-archive.com/[email protected]/msg29667.html. I will retest both issues on the next release

[oniko]

Hi, Arvin, saamalik I think I got it. I'll create new pull request with the explanation and proposal for a fix...