Hi, The following patches fix a couple of issues with the permission check we do in vfs_dedupe_file_range(). The first patch expands our check to allow dedupe of a readonly file if the user owns it. Existing behavior is that we'll allow dedupe only if: - the user is an admin (root) - the user has the file open for write This makes it impossible for a user to dedupe their own file set unless they do it as root, or ensure that all files have write permission. There's a couple of duperemove bugs open for this: https://github.com/markfasheh/duperemove/issues/129 https://github.com/markfasheh/duperemove/issues/86 The solution is simple - we allow dedupe of the target if the user owns it. With that patch, a user can dedupe all of their files. The 2nd patch fixes our return code for permission denied to be EPERM. For some reason we're returning EINVAL - I think that's probably my fault. At any rate, we need to be returning something descriptive of the actual problem, otherwise callers see EINVAL and can't really make a valid determination of what's gone wrong. This has also popped up in duperemove, mostly in the form of cryptic error messages. Because this is a code returned to userspace, I did check the other users of extent-same that I could find. Both 'bees' and 'rust-btrfs' do the same as duperemove and simply report the error (as they should). The patches are also available in git: git pull https://github.com/markfasheh/linux dedupe-perms Thanks, --Mark
