For context I am making a file based deduplication tool. I found that in this commit 5de4480ae7f8 ("vfs: allow dedupe of user owned read-only files") it states: > - the process could get write access However the behavior added in allow_file_dedupe now may_dedupe_file is opposite: > + if (!inode_permission(file_inode(file), MAY_WRITE)) > + return true I've tested that I can create an other readonly file as root and have my unprivileged user deduplicate it however if I then make the file other writeable I cannot anymore*. It doesn't make sense to me why giving write permissions on a file should remove the permission to deduplicate*. I'm not sure on how to fix this, flipping the condition would work but that is a breaking change and idk if this is ok here. Adding a check to also users who have write access to the file would remove all the logic here since you would always be allowed to dedup FDs you managed to get your hands on. Any input on this welcome, thx *without opening the file in write mode which I don't want to do because it can prevent execution of files which is the exact thing is 5de4480ae7f8 were trying to address in the first place