On Tue, Aug 26, 2025 at 2:21 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > [ > This is on top of -rc3; if nobody objects, I'll insert that early in series > in viro/vfs.git#work.mount. It has an impact for LSM folks - ->sb_kern_mount() > would be called without ->s_umount; nothing in-tree cares, but if you have > objections, yell now. > ] Thanks for the heads-up, I'm not aware of anyone currently posting/working-on patches that would be dependent on this. > Prior to the call of do_new_mount_fc() the caller has just done successful > vfs_get_tree(). Then do_new_mount_fc() does several checks on resulting > superblock, and either does fc_drop_locked() and returns an error or > proceeds to unlock the superblock and call vfs_create_mount(). > > The thing is, there's no reason to delay that unlock + vfs_create_mount() - > the tests do not rely upon the state of ->s_umount and > fc_drop_locked() > put_fs_context() > is equivalent to > unlock ->s_umount > put_fs_context() > > Doing vfs_create_mount() before the checks allows us to move vfs_get_tree() > from caller to do_new_mount_fc() and collapse it with vfs_create_mount() > into an fc_mount() call. > > Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> -- paul-moore.com
