rootfs-block: add support for the rootfallback= kernel cmdline option

diff --git a/dracut.cmdline.7.asc b/dracut.cmdline.7.asc
index 09c47e854d7ef77116032bd7bdcf983e0f8e8899..4b2ab03509f89250121bb604ccf749d0ce9f329a 100644 (file)
--- a/dracut.cmdline.7.asc
+++ b/dracut.cmdline.7.asc
@@ -69,6 +69,12 @@ rootfstype=ext3
     force mounting _/_ and _/usr_ (if it is a separate device) read-write.
     See also ro option.
 
+**rootfallback=**_<path to blockdevice>_::
+    specify the block device to use as the root filesystem, if the normal root cannot be found.
+    This can only be a simple block device with a simple file system, for which the filesystem
+    driver is either compiled in, or added manually to the initramfs.
+    This parameter can be specified multiple times.
+
 **rd.auto** **rd.auto=1**::
     enable autoassembly of special devices like cryptoLUKS, dmraid, mdraid or lvm.
     Default is off as of dracut version >= 024.

diff --git a/modules.d/95rootfs-block/module-setup.sh b/modules.d/95rootfs-block/module-setup.sh
index f066a79c0de809ba17cad0e3cea85c396c9a7146..7e714eb0dad8f514ed376f4c14758dfab78e994f 100755 (executable)
--- a/modules.d/95rootfs-block/module-setup.sh
+++ b/modules.d/95rootfs-block/module-setup.sh
@@ -44,5 +44,6 @@ install() {
         inst_hook pre-udev 30 "$moddir/block-genrules.sh"
         inst_hook mount 99 "$moddir/mount-root.sh"
     fi
-}
 
+    inst_hook initqueue/timeout 99 "$moddir/rootfallback.sh"
+}

diff --git a/modules.d/95rootfs-block/rootfallback.sh b/modules.d/95rootfs-block/rootfallback.sh
new file mode 100755 (executable)
index 0000000..246ce9a
--- /dev/null
+++ b/modules.d/95rootfs-block/rootfallback.sh
@@ -0,0 +1,46 @@
+#!/bin/sh
+# -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
+# ex: ts=8 sw=4 sts=4 et filetype=sh
+
+type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
+
+for root in $(getargs rootfallback=); do
+    case "$root" in
+        block:LABEL=*|LABEL=*)
+            root="${root#block:}"
+            root="$(echo $root | sed 's,/,\\x2f,g')"
+            root="/dev/disk/by-label/${root#LABEL=}"
+            ;;
+        block:UUID=*|UUID=*)
+            root="${root#block:}"
+            root="${root#UUID=}"
+            root="$(echo $root | tr "[:upper:]" "[:lower:]")"
+            root="/dev/disk/by-uuid/${root#UUID=}"
+            ;;
+        block:PARTUUID=*|PARTUUID=*)
+            root="${root#block:}"
+            root="${root#PARTUUID=}"
+            root="$(echo $root | tr "[:upper:]" "[:lower:]")"
+            root="/dev/disk/by-partuuid/${root}"
+            ;;
+        block:PARTLABEL=*|PARTLABEL=*)
+            root="${root#block:}"
+            root="/dev/disk/by-partlabel/${root#PARTLABEL=}"
+            ;;
+    esac
+
+    if ! [ -b "$root" ]; then
+        warn "Could not find rootfallback $root"
+        continue
+    fi
+
+    if mount "$root" /sysroot; then
+        info "Mounted rootfallback $root"
+        exit 0
+    else
+        warn "Failed to mount rootfallback $root"
+        exit 1
+    fi
+done
+
+[ -e "$job" ] && rm -f "$job"