KVM: Is it possible to detect guest disk was mounted RW?

Question

Let's assume I have a KVM-based virtual machine. There is a volume that contains the operating system and the data.

I know it is possible to access from host at least READ-ONLY the filesystem which is on guest.

If it is possible to access the guest FS in RW mode, then could I somehow detect that the filesystem was mounted?

The filesystem is ext4, is it storing any information about how and when it was mounted?

@MichaelHampton I would have expected that to work. But when I verified with `tune2fs` on a file system definitely mounted rw, I saw this: `Filesystem state: clean`. I think that's because that bit has a different meaning when journaling is in use. — kasperd, Oct 19 '18 at 19:32

score 1 · Answer 1 · answered May 06 '19 at 03:37

There are 2 things LV Write Access read/write and # open 2 first one is disk is open as read/write and second one is open count.

$ lvdisplay -v /dev/vg_root/lv_swap --- Logical volume --- LV Path /dev/vg_root/lv_swap LV Name lv_swap VG Name vg_root LV UUID SyLfHM-iiKk-Kkxn-O6r9-6DaV-kTFI-7Uvzpb LV Write Access read/write LV Creation host, time localhost.localdomain, 2019-04-12 14:47:37 +0000 LV Status available # open 2 LV Size 1.00 GiB Current LE 256 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:1

KVM: Is it possible to detect guest disk was mounted RW?

1 Answers1