live-iso: add erofs support

[nikita-dubrovskii]

No description provided.

[dustymabe]

Not sure if there are any consequences for removing Type= but it sounds good to me if there aren't any. I'm sure the kernel just autodetects here.

[nikita-dubrovskii]

Yes, there is no need for that

[jlebon]

I don't think it's the kernel doing the auto-detection here, but util-linux. I think in general it's better to specify the type you expect to not rely on it getting it right and just be more strict. One way that I think should work here is to make this an env var and then add an EnvironmentFile that we populate from coreos-livepxe-rootfs.sh.

[dustymabe]

While we can write out an override from coreos-livepxe-rootfs.sh for this particular mount where we can set the Type that won't be so easy for the sysroot.mount from ~line 150 because we don't know whether the file inside the rootfs.img is erofs or squashfs at that point in time.

[dustymabe]

For setting the What= and Type= here this seems to work:

diff --git a/overlay.d/05core/usr/lib/dracut/modules.d/35coreos-live/coreos-livepxe-rootfs.sh b/overlay.d/05core/usr/lib/dracut/modules.d/35coreos-live/coreos-livepxe-rootfs.sh
index 61b4661f..d62443ab 100755
--- a/overlay.d/05core/usr/lib/dracut/modules.d/35coreos-live/coreos-livepxe-rootfs.sh
+++ b/overlay.d/05core/usr/lib/dracut/modules.d/35coreos-live/coreos-livepxe-rootfs.sh
@@ -88,6 +88,20 @@ else
 fi
 
 # we support both squashfs and erofs, let's create the symlink for sysroot.mount
-sysroot=$(ls /root.*fs)
-echo "Creating symlink '/sysrootfs.img -> ${sysroot}'"
-ln -s "${sysroot}" /sysrootfs.img
+if [ -f /root.squashfs ]; then
+    fs='/root.squashfs'
+    fstype='squashfs'
+elif [ -f /root.erofs ]; then
+    fs='/root.erofs'
+    fstype='erofs'
+else
+    echo "No root.squashfs or root.erofs exists" >&2
+    exit 1
+fi
+
+# Let sysroot.mount know what path and type to use for mounting
+echo "Updating /rootfs.env with WHAT=${fs} TYPE=${fstype}"
+cat >/rootfs.env <<EOF
+WHAT=${fs}
+TYPE=${fstype}
+EOF
diff --git a/overlay.d/05core/usr/lib/dracut/modules.d/35coreos-live/live-generator b/overlay.d/05core/usr/lib/dracut/modules.d/35coreos-live/live-generator
index 9c052e5a..013a8d23 100755
--- a/overlay.d/05core/usr/lib/dracut/modules.d/35coreos-live/live-generator
+++ b/overlay.d/05core/usr/lib/dracut/modules.d/35coreos-live/live-generator
@@ -58,18 +58,19 @@ isoroot=$(getarg coreos.liveiso= ||:)
 if [ -z "${isoroot}" ]; then
     # In this case, the rootfs is already unpacked into the initrd, or we need
     # to retrieve it
-    cat >"${UNIT_DIR}/sysroot.mount" <<EOF
+    cat >"${UNIT_DIR}/sysroot.mount" <<'EOF'
 # Automatically generated by live-generator
 
 [Unit]
 DefaultDependencies=false
-# Verifies that we have the right sysrootfs.img, or downloads it if needed
+# Verifies that we have the right rootfs image, or downloads it if needed
 After=coreos-livepxe-rootfs.service
 Before=initrd-root-fs.target
-
 [Mount]
-What=/sysrootfs.img
+EnvironmentFile=/rootfs.env
+What=${WHAT}
 Where=/sysroot
+Type=${TYPE}
 Options=loop
 EOF
 else

but I'm not opposed to leaving it the way it is either.

[jlebon]

For setting the What= and Type= here this seems to work:

Ahh yes, I do like the explicitness of just templating the What also actually.

[nikita-dubrovskii]

So, should i add Dusty's patch on top ? Does it make sense to have this explicity just in 1 place, while omitting the else case?

[dustymabe]

the code LGTM - I'll test it out today.

[nikita-dubrovskii]

PXE installation doesn't work:

[    1.631722] ls:                                                                                                                                             
[    1.631725] cannot access '/root.*fs'  

Fixing ...

[nikita-dubrovskii]

Now PXE works, here are logs

root.squashfs

[  OK  ] Mounted run-ephemeral.mount - /run/ephemeral.                                                                                                         
[    4.833554] coreos-livepxe-rootfs[806]: Creating symlink to /root.squashfs                                                                                  
[  OK  ] Finished coreos-livepxe-rootfs.ser…ce - Acquire Live PXE rootfs Image.                                                                                
[    4.835793] systemd[1]: Mounting sysroot.mount - /sysroot...                                                                                                
[  OK  ] Mounted sysroot.mount - /sysroot.                                                                                                                     

root.erofs:

[  OK  ] Mounted run-ephemeral.mount - /run/ephemeral.                                                                                                         
[    9.394641] coreos-livepxe-rootfs[780]: Creating symlink to /root.erofs                                                                                     
[  OK  ] Finished coreos-livepxe-rootfs.ser…ce - Acquire Live PXE rootfs Image.
[    9.398447] systemd[1]: Mounting sysroot.mount - /sysroot...                                                                                                                                    
[    9.480587] erofs: (device loop1): mounted with root inode @ nid 208.                                                                                       
[  OK  ] Mounted sysroot.mount - /sysroot.