On Thu, 2021-11-04 at 14:50 +0100, Miklos Szeredi wrote: > On Thu, 4 Nov 2021 at 14:27, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > > > Hi Miklos! > > > > I was looking at an issue [1] with ceph-fuse and noticed that statfs > > always reports f_fsid == 0 via statfs. Is there a reason for not letting > > the driver fill out that field? > > Hi Jeff, > > I do not remember ever hearing of this field. The statfs(2) man page > doesn't make it very obvious either: > > The f_fsid field > > [...] The general idea is that f_fsid contains some random > stuff such that > the pair (f_fsid,ino) uniquely determines a file. Some operating sys‐ > tems use (a variation on) the device number, or the device number com‐ > bined with the filesystem type. [...] > > I'd be somewhat concerned about allowing an unprivileged fuse server > to fill this, as that may allow impersonation of another filesystem. > > For a privileged fuse server I see no problem with allowing to set this. Thanks, Miklos, Good point about impersonation. I'll have to think about whether it's worthwhile to change this for privileged servers. Cheers, -- Jeff Layton <jlayton@xxxxxxxxxx>
