Initial import

1 files changed, 78 insertions, 0 deletions

diff --git a/growfs-hook b/growfs-hook
new file mode 100644
index 000000000000..19e63e5ee35d
--- /dev/null
+++ b/growfs-hook
@@ -0,0 +1,78 @@
+#!/bin/sh
+
+run_hook() {
+  echo "GrowRootFS: starting"
+
+  # if a file indicates we should do nothing, then just exit
+  for f in /var/lib/cloud/instance/root-grown /etc/growroot-disabled \
+      /etc/growroot-grown; do
+    [ -f "${rootmnt}$f" ] && echo "GrowRootFS: disabled by file" && return 0
+  done
+
+  # figure out what disk '$root' is on
+  { [ ! -L "${root}" ] && rootdev=${root} || rootdev=$(readlink -f "${root}") ; } || { echo "failed to get target of link for ${root}" && return 0 ; }
+
+  case "${rootdev}" in
+    *[0-9]) : ;;
+    # the root is a disk, not a partition (does not end in a digit)
+    # no need to do anything in this case, kernel already knows the full size.
+    *) echo "GrowRootFS: ${rootdev} is a disk, not a partition, no action" && return 0 ;;
+  esac
+
+  # remove all consective numbers from the end of rootdev to get 'rootdisk'
+  rootdisk=${rootdev}
+  while [ "${rootdisk%[0-9]}" != "${rootdisk}" ]; do
+    rootdisk=${rootdisk%[0-9]};
+  done
+  partnum=${rootdev#${rootdisk}}
+
+  # if the basename of the root device (ie 'xvda1' or 'sda1') exists
+  # in /sys/block/ then it is a block device, not a partition
+  # (xen xvda1 is an example of such a funny named block device)
+  [ -e "/sys/block/${rootdev##*/}" ] && echo "GrowRootFS: ${rootdev} is a block device" && return 0
+
+  # if growpart fails, exit.
+  # we capture stderr because on success of dry-run, it writes
+  # to stderr what it would do.
+  out=$(growpart --dry-run "${rootdisk}" "${partnum}" 2>&1) || { echo "GrowRootFS: ${out}" && return 1; }
+
+  # if growpart would change something, --dry-run will write something like
+  #  CHANGE: partition=1 start=2048 old: size=1024000 end=1026048 new: size=2089192,end=2091240
+  # anything else, exit
+  case "${out}" in
+    CHANGE:*) :;;
+    *) echo "GrowRootFS: ${out}" && return 0;;
+  esac
+
+  ## Wait for any of the initial udev events to finish
+  ## This is to avoid any other processes using the block device that the
+  ## root partition is on, which would cause the sfdisk 'BLKRRPART' to fail.
+  udevadm settle --timeout ${rootdelay:-30} || { echo "GrowRootFS: WARNING: udevadm settle prior to growpart failed" && return 1 ; }
+
+  if out=$(growpart "${rootdisk}" "${partnum}" 2>&1); then
+    case "$out" in
+      CHANGED:*) echo "GrowRootFS: $out";;
+      NOCHANGE:*)
+        echo "GrowRootFS: WARNING: expected to grow partition, but did not";;
+      *) echo "GrowRootFS: unexpected output: ${out}"
+    esac
+  else
+    echo "GrowRootFS: WARNING: resize failed: $out"
+  fi
+
+  ## Wait for the partition re-read events to complete
+  ## so that the root partition is available when we try and mount it.
+  udevadm settle --timeout ${rootdelay:-30}
+
+  # Need to figure out the rootfs type somehow
+  # For now we only support ext2/3/4
+  fsck -f ${rootdev}
+  resize2fs -p ${rootdev}
+
+  ## write to /etc/grownroot-grown. most likely this wont work (readonly)
+  { date --utc > "${rootmnt}/etc/growroot-grown" ; } >/dev/null 2>&1 || :
+
+  echo "GrowRootFS: done"
+  sleep 1
+
+}