[systemd-devel] tentative state and unmount on mapper

[Umut Tezduyar Lindskog]

On Mon, May 18, 2015 at 3:59 PM, Umut Tezduyar Lindskog
<umut at tezduyar.com> wrote:
> Hi,
>
> There have been few discussions about tentative state and unmounting
> and I am experiencing different problem in the same device logic.
>
> I am at 219 + 628c89cc + 496068a8 + 5259bcf6
>
> I have 2 mounts (one is bind mount) on mapper device.
>
> /proc/self/mountinfo:
> 47 37 254:0 / /var/spool/storage/SD_DISK
> rw,nosuid,nodev,noexec,noatime,nodiratime shared:18 - ext4
> /dev/mapper/mmcblk0p1 rw,journal_checksum,commit=1,data=ordered
> 49 37 254:0 / /var/spool/storage/areas/SD_DISK/root
> rw,nosuid,nodev,noexec,noatime,nodiratime shared:18 - ext4
> /dev/mapper/mmcblk0p1 rw,journal_checksum,commit=1,data=ordered
>
> systemctl -t device --all | grep map:
> dev-mapper-mmcblk0p1.device   loaded activating tentative /dev/mapper/mmcblk0p1
>
> As soon as I unmount the bind mount, systemd picks up the change in
> /proc/self/mountinfo and changes the "tentative" device to "dead" and
> due to that all file systems BindsTo to the device are being
> unmounted. Application which mounted the partitions is not getting a
> chance to unmount the fs.
>
> Should I enumerate available mount units to see if anyone else has
> been mounted on the device that is about to be set as DEVICE_DEAD in
> device_update_found_one()?

For the achieve purpose, Lennart has implemented something similar at
394763f6 and fcd8b266. Things have worked for me. But the proper
solution is enabling udev awareness for DM/LVM.

Umut

>
> Umut