e2scrub_all: refactor device probe loop

Paul Menzel reported that the e2scrub_all reaper service that runs at
startup takes a long time to run, and Ted Ts'o pointed out that we could
do a lot less work by using lvs as the outer loop in the ext4 filesystem
probe function so that we only have to lsblk the lvm devices containing
ext4 filesystems.

Therefore, refactor the loops to put lvs first, which should boost speed
a bit.

[ Made some of the further optimizations suggested by Lukas Czerner.  -- TYT ]

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Darrick J. Wong 2019-03-18 17:17:32 -07:00 committed by Theodore Ts'o
parent c120312253
commit c7d6525eca

View File

@ -22,6 +22,7 @@ PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
scrub_all=0
snap_size_mb=256
reap=0
conffile="@root_sysconfdir@/e2scrub.conf"
test -f "${conffile}" && . "${conffile}"
@ -65,7 +66,7 @@ exitcode() {
while getopts "nrAV" opt; do
case "${opt}" in
"n") DBG="echo Would execute: " ;;
"r") scrub_args="${scrub_args} -r";;
"r") scrub_args="${scrub_args} -r"; reap=1;;
"A") scrub_all=1;;
"V") print_version; exitcode 0;;
*) print_help; exitcode 2;;
@ -88,36 +89,30 @@ if ! type lvcreate >& /dev/null ; then
fi
# Find scrub targets, make sure we only do this once.
ls_scrub_targets() {
lsblk -o NAME,FSTYPE,MOUNTPOINT -p -P -n | while read vars; do
ls_scan_targets() {
lsblk -o NAME,MOUNTPOINT,FSTYPE -P -n -p \
$(lvs -o lv_path --noheadings -S "lv_active=active,lv_role=public,lv_role!=snapshot,vg_free>${snap_size_mb}") | \
grep FSTYPE=\"ext\[234\]\" | while read vars ; do
eval "${vars}"
# Skip non-ext[234]
case "${FSTYPE}" in
ext[234]) ;;
*) continue;;
esac
# Skip unmounted filesystems unless -A
if [ "${scrub_all}" -eq 0 ] && [ -z "${MOUNTPOINT}" ]; then
continue;
if [ "${scrub_all}" -eq 1 ] || [ -n "${MOUNTPOINT}" ]; then
echo ${MOUNTPOINT:-${NAME}}
fi
done
}
# Skip non-lvm devices and lvm snapshots
lvm_vars="$(lvs --nameprefixes -o vg_name,lv_name,lv_role --noheadings "${NAME}" 2> /dev/null)"
test $? -ne 0 && continue
eval "${lvm_vars}"
echo "${LVM2_LV_ROLE}" | grep -q "snapshot" && continue
# Find leftover scrub snapshots
ls_reap_targets() {
lvs -o lv_path -S lv_role=snapshot -S lv_name=~\(e2scrub$\) --noheadings
}
free_space="$(vgs -o vg_free --units m --noheadings --no-suffix "${LVM2_VG_NAME}" 2> /dev/null | sed -e 's/\..*//')"
test "${snap_size_mb}" -gt "${free_space}" && continue
if [ -n "${MOUNTPOINT}" ]; then
echo "${MOUNTPOINT}"
else
echo "${NAME}"
fi
done | sort | uniq
# Figure out what we're targeting
ls_targets() {
if [ "${reap}" -eq 1 ]; then
ls_reap_targets
else
ls_scan_targets
fi
}
# systemd doesn't know to do path escaping on the instance variable we pass
@ -140,10 +135,10 @@ escape_path_for_systemd() {
# Scrub any mounted fs on lvm by creating a snapshot and fscking that.
stdin="$(realpath /dev/stdin)"
ls_scrub_targets | while read tgt; do
ls_targets | while read tgt; do
# If we're not reaping and systemd is present, try invoking the
# systemd service.
if [ -z "${scrub_args}" ] && type systemctl > /dev/null 2>&1; then
if [ "${reap}" -ne 1 ] && type systemctl > /dev/null 2>&1; then
tgt_esc="$(escape_path_for_systemd "${tgt}")"
${DBG} systemctl start "e2scrub@${tgt_esc}" 2> /dev/null < "${stdin}"
res=$?