On Wed, Aug 21, 2019, 01:15 Tony Rodriguez <unixpro1...@gmail.com> wrote:
> I modified systemd-219 functionality to meet a custom requirement for > detecting filesystems/devices that use iscsi without using the _netdev > keyword in /etc/fstab. It is a strict requirement regarding not using > _netdev that I have no control over. However, I am stuck. > > From my understanding, src/fstab-generator.c is used to determine > LOCAL-FS and REMOTE-FS. I have modified fstab-generator.c to search for > iscsi udev devices which works, provided the system is already fully > booted (typical multi-user state type of thing). I can also find > /dev/disk/ block devices including iscsi devices using my logic within > fstab-generator.c. The problem is when the system reboots, it appears > systemd using the same fstab-generator logic that I implemented is > unable to detect any iscsi devices. After doing some research, it > appears normal systemd behavior is to mount / and /usr then invoke > fstab-generator.c to determine if a given filesystem in /etc/fstab > should be a local or remote target. > / and /usr are mounted by initramfs before systemd starts. (If your initramfs itself uses systemd, that's mostly independent from the main-root systemd – they're two separate worlds.) > The problem is I have no way to tell if a given iscsi filesystem/device > specified in /etc/fstab (without the _netdev keyord ) is local/remote > during the booting state. Mainly because devices are not yet populated > in /dev/disk or udev. Is there a way I can determine if a > filesystem/mount point/device specified in /etc/fstab is local or remote > without the _netdev or fstype (which handles nfs, etc) keywords within > fstab-generator.c? By design, generators run before any services have started, so no udev yet. (But if you had udev in the initramfs, it could store data in /run that you could then read from a generator.) If checking udev and /dev/disk are not possible > within fstab-generator.c, because such devices are not yet populated, > then what should I modify within the systemd source so I can determine > such local/remote targets myself and pass it to fstab-generator.c > (especially when the system is in that / and /usr mounting state and > udev devices are not yet populated? > If you can't use _netdev, then use custom options. Fstab now supports arbitrary "x-" prefixed options, and systemd fstab generator already recognizes several such as "x-systemd.requires=iscsid-is-ready.target". (I think they're listed in the systemd.mount manpage?)
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