On Tue, Jun 28, 2022 at 8:44 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > On Mon, Jun 27, 2022 at 04:11:07PM -0600, James Yonan wrote: > > > && d_is_positive(new_dentry) > > && timespec64_compare(&d_backing_inode(old_dentry)->i_mtime, > > &d_backing_inode(new_dentry)->i_mtime) <= 0) > > goto exit5; > > > > It's pretty cool in a way that a new atomic file operation can even be > > implemented in just 5 lines of code, and it's thanks to the existing > > locking infrastructure around file rename/move that these operations > > become almost trivial. Unfortunately, every fs must approve a new > > renameat2() flag, so it bloats the patch a bit. > > How is it atomic and what's to stabilize ->i_mtime in that test? > Confused... Good point. RENAME_EXCHANGE_WITH_NEWER would have been better in that regard. And you'd have to check in vfs_rename() after lock_two_nondirectories() Thanks, Amir.
