reflink original photos

[vojta001]

Some linux filesystems support lightweight copy-on-write copies of files. Unlike symlinks, they do not break when the original file is moved or deleted. Unlike with hardlinks, changes to the original files do not propagate. Unlike regular copies, they do not take twice the space.

I propose to add an reflink option to --photo-preview, --video-preview, --photo-download and --video-download that acts as copy, but forces reflink creation.

I am willing to help with the implementation, should the maintainers like the idea.

[rprieto]

Thanks for suggesting this feature. It sounds interesting!

What will be the behaviour if a source file changes? Thumbsup compares the last modified date of the source and target files. Will the target (reflink) appear outdated? Could thumbsup force an update to the reflink?

For the implementation it looks straightforward with fs.copyFile (that we already use for the regular copy) and the COPYFILE_FICLONE or COPYFILE_FICLONE_FORCE flags.

[vojta001]

The files don't know about each other, it's just a hidden deduplication down there. No data or metadata changes propagate in either direction, so should the last modified date get bumped somehow on the original, it won't match the target.