Hi, I'm looking for testers: - Fedora 33 - User home is on Btrfs (clean installed or converted, in a subvolume or not, these details won't matter) - using any spin other than Workstation (kde, lxqt, xfce, etc are all requested). I'd like to know which desktops do/don't automagically support reflink copies. What are reflinks? See Note 1 below. 1. Use the file manager to duplicate a file anywhere within user home, by all available means. i.e. using control-c then control-v, or contextual menu copy/paste, or copy to... if available. (Any file? Yes, although I'm most interested in files 4KiB and larger. The handling for smaller files might be different.) 2. Copy it from/to anywhere in your user home directory. 3. Check all copies of the file with 'filefrag -v /path/to/file' Check: The main thing you're looking for is that flags is "shared" for the original and each copy. An extra check is verify all the column values are the same for the original and each of its copies. ext: logical_offset: physical_offset: length: expected: flags: 0: 0.. 7429: 16640282.. 16647711: 7430: last,shared,eof Thanks! Note 1: What is a reflink copy? Also known as efficient copies, only file metadata is copied to a new inode. Both inodes point to the same data blocks (extents), thus creating "shared extents". If any such copy's data is modified, it "breaks" the shared extents, and the modified extents become unique only to the modified file. If merely the metadata is changed, extents remain shared and just the file metadata is update. For example, you could have two files with different ownership or SELinux labels, but share the same data extents. Note 2: It's decently likely you will get the expected results if /home is on XFS. Arguably if we get a result on Btrfs indicating -- Chris Murphy _______________________________________________ test mailing list -- test@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to test-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/test@xxxxxxxxxxxxxxxxxxxxxxx
