On Thu, Jan 31, 2019 at 02:41:06PM +1100, Dave Chinner wrote: > On Thu, Jan 31, 2019 at 10:47:12AM +0900, Wang Shilong wrote: > > From: Wang Shilong <wshilong@xxxxxxx> > > > > Currently there is no way to change project ID of > > symlink file itself, this is important to implement > > Directory quota for an existed directory. > > This seems like something open(O_PATH|O_NOFOLLOW) should allow. > from open(2): ...but I thought O_PATH|O_NOFOLLOW file descriptions didn't allow ioctl calls? $ ln -sf urk /mnt/cow $ xfs_io -c 'open -PL /mnt/cow' -c 'chproj 6' setprojid: Bad file descriptor $ ls -la /mnt/ lrwxrwxrwx 1 root root 3 Jan 31 09:30 /mnt/cow -> moo > If pathname is a symbolic link and the O_NOFOLLOW flag is > also specified, then the call returns a file descriptor > referring to the symbolic link. This file descriptor > can be used as the dirfd argument in calls to fchownat(2), > fstatat(2), linkat(2), and read¿ linkat(2) with an empty > pathname to have the calls operate on the symbolic link. > > Changing the project id is the equivalent of fchownat()..... /me & others wonder (on the ext4 call) if maybe we should promote project id to a vfs level concept? i.e. store project id in struct inode instead of the fs-specific inode structures. Then we can use the existing setattr infrastructure to persist those changes. As for fchownat, how about a new flag that means "use the value in the gid field to set the project id"? --D > Cheers, > > Dave. > -- > Dave Chinner > david@xxxxxxxxxxxxx
