freebsd-nq/scripts/zfs.sh
Serapheim Dimitropoulos a7ed98d8b5 OpenZFS 9330 - stack overflow when creating a deeply nested dataset
Datasets that are deeply nested (~100 levels) are impractical. We just
put a limit of 50 levels to newly created datasets. Existing datasets
should work without a problem.

The problem can be seen by attempting to create a dataset using the -p
option with many levels:

    panic[cpu0]/thread=ffffff01cd282c20: BAD TRAP: type=8 (#df Double fault) rp=ffffffff

    fffffffffbc3aa60 unix:die+100 ()
    fffffffffbc3ab70 unix:trap+157d ()
    ffffff00083d7020 unix:_patch_xrstorq_rbx+196 ()
    ffffff00083d7050 zfs:dbuf_rele+2e ()
    ...
    ffffff00083d7080 zfs:dsl_dir_close+32 ()
    ffffff00083d70b0 zfs:dsl_dir_evict+30 ()
    ffffff00083d70d0 zfs:dbuf_evict_user+4a ()
    ffffff00083d7100 zfs:dbuf_rele_and_unlock+87 ()
    ffffff00083d7130 zfs:dbuf_rele+2e ()
    ... The block above repeats once per directory in the ...
    ... create -p command, working towards the root ...
    ffffff00083db9f0 zfs:dsl_dataset_drop_ref+19 ()
    ffffff00083dba20 zfs:dsl_dataset_rele+42 ()
    ffffff00083dba70 zfs:dmu_objset_prefetch+e4 ()
    ffffff00083dbaa0 zfs:findfunc+23 ()
    ffffff00083dbb80 zfs:dmu_objset_find_spa+38c ()
    ffffff00083dbbc0 zfs:dmu_objset_find+40 ()
    ffffff00083dbc20 zfs:zfs_ioc_snapshot_list_next+4b ()
    ffffff00083dbcc0 zfs:zfsdev_ioctl+347 ()
    ffffff00083dbd00 genunix:cdev_ioctl+45 ()
    ffffff00083dbd40 specfs:spec_ioctl+5a ()
    ffffff00083dbdc0 genunix:fop_ioctl+7b ()
    ffffff00083dbec0 genunix:ioctl+18e ()
    ffffff00083dbf10 unix:brand_sys_sysenter+1c9 ()

Porting notes:
* Added zfs_max_dataset_nesting module option with documentation.
* Updated zfs_rename_014_neg.ksh for Linux.
* Increase the zfs.sh stack warning to 15K.  Enough time has passed
  that 16K can be reasonably assumed to be the default value.  It
  was increased in the 3.15 kernel released in June of 2014.

Authored by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Garrett D'Amore <garrett@damore.org>

OpenZFS-issue: https://www.illumos.org/issues/9330
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/757a75a
Closes #7681
2018-07-09 13:02:50 -07:00

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#!/bin/sh
#
# A simple script to load/unload the ZFS module stack.
#
BASE_DIR=$(dirname "$0")
SCRIPT_COMMON=common.sh
if [ -f "${BASE_DIR}/${SCRIPT_COMMON}" ]; then
. "${BASE_DIR}/${SCRIPT_COMMON}"
else
echo "Missing helper script ${SCRIPT_COMMON}" && exit 1
fi
PROG=zfs.sh
VERBOSE="no"
UNLOAD="no"
ZED_PIDFILE=${ZED_PIDFILE:-/var/run/zed.pid}
LDMOD=${LDMOD:-/sbin/modprobe}
KMOD_ZLIB_DEFLATE=${KMOD_ZLIB_DEFLATE:-zlib_deflate}
KMOD_ZLIB_INFLATE=${KMOD_ZLIB_INFLATE:-zlib_inflate}
KMOD_SPL=${KMOD_SPL:-spl}
KMOD_ZAVL=${KMOD_ZAVL:-zavl}
KMOD_ZNVPAIR=${KMOD_ZNVPAIR:-znvpair}
KMOD_ZUNICODE=${KMOD_ZUNICODE:-zunicode}
KMOD_ZCOMMON=${KMOD_ZCOMMON:-zcommon}
KMOD_ZLUA=${KMOD_ZLUA:-zlua}
KMOD_ICP=${KMOD_ICP:-icp}
KMOD_ZFS=${KMOD_ZFS:-zfs}
usage() {
cat << EOF
USAGE:
$0 [hvud] [module-options]
DESCRIPTION:
Load/unload the ZFS module stack.
OPTIONS:
-h Show this message
-v Verbose
-u Unload modules
EOF
}
while getopts 'hvu' OPTION; do
case $OPTION in
h)
usage
exit 1
;;
v)
VERBOSE="yes"
;;
u)
UNLOAD="yes"
;;
?)
usage
exit
;;
esac
done
kill_zed() {
if [ -f "$ZED_PIDFILE" ]; then
PID=$(cat "$ZED_PIDFILE")
kill "$PID"
fi
}
check_modules() {
LOADED_MODULES=""
MISSING_MODULES=""
for KMOD in $KMOD_SPL $KMOD_ZAVL $KMOD_ZNVPAIR \
$KMOD_ZUNICODE $KMOD_ZCOMMON $KMOD_ZLUA $KMOD_ICP $KMOD_ZFS; do
NAME=$(basename "$KMOD" .ko)
if lsmod | grep -E -q "^${NAME}"; then
LOADED_MODULES="$LOADED_MODULES\t$NAME\n"
fi
if ! modinfo "$KMOD" >/dev/null 2>&1; then
MISSING_MODULES="$MISSING_MODULES\t${KMOD}\n"
fi
done
if [ -n "$LOADED_MODULES" ]; then
printf "Unload the kernel modules by running '%s -u':\n" "$PROG"
printf "%b" "$LOADED_MODULES"
exit 1
fi
if [ -n "$MISSING_MODULES" ]; then
printf "The following kernel modules can not be found:\n"
printf "%b" "$MISSING_MODULES"
exit 1
fi
return 0
}
load_module() {
KMOD=$1
FILE=$(modinfo "$KMOD" | awk '/^filename:/ {print $2}')
VERSION=$(modinfo "$KMOD" | awk '/^version:/ {print $2}')
if [ "$VERBOSE" = "yes" ]; then
echo "Loading: $FILE ($VERSION)"
fi
$LDMOD "$KMOD" >/dev/null 2>&1
# shellcheck disable=SC2181
if [ $? -ne 0 ]; then
echo "Failed to load $KMOD"
return 1
fi
return 0
}
load_modules() {
mkdir -p /etc/zfs
if modinfo "$KMOD_ZLIB_DEFLATE" >/dev/null 2>&1; then
modprobe "$KMOD_ZLIB_DEFLATE" >/dev/null 2>&1
fi
if modinfo "$KMOD_ZLIB_INFLATE">/dev/null 2>&1; then
modprobe "$KMOD_ZLIB_INFLATE" >/dev/null 2>&1
fi
for KMOD in $KMOD_SPL $KMOD_ZAVL $KMOD_ZNVPAIR \
$KMOD_ZUNICODE $KMOD_ZCOMMON $KMOD_ZLUA $KMOD_ICP $KMOD_ZFS; do
load_module "$KMOD" || return 1
done
if [ "$VERBOSE" = "yes" ]; then
echo "Successfully loaded ZFS module stack"
fi
return 0
}
unload_module() {
KMOD=$1
NAME=$(basename "$KMOD" .ko)
FILE=$(modinfo "$KMOD" | awk '/^filename:/ {print $2}')
VERSION=$(modinfo "$KMOD" | awk '/^version:/ {print $2}')
if [ "$VERBOSE" = "yes" ]; then
echo "Unloading: $KMOD ($VERSION)"
fi
rmmod "$NAME" || echo "Failed to unload $NAME"
return 0
}
unload_modules() {
for KMOD in $KMOD_ZFS $KMOD_ICP $KMOD_ZLUA $KMOD_ZCOMMON $KMOD_ZUNICODE \
$KMOD_ZNVPAIR $KMOD_ZAVL $KMOD_SPL; do
NAME=$(basename "$KMOD" .ko)
USE_COUNT=$(lsmod | grep -E "^${NAME} " | awk '{print $3}')
if [ "$USE_COUNT" = "0" ] ; then
unload_module "$KMOD" || return 1
fi
done
if modinfo "$KMOD_ZLIB_DEFLATE" >/dev/null 2>&1; then
modprobe -r "$KMOD_ZLIB_DEFLATE" >/dev/null 2>&1
fi
if modinfo "$KMOD_ZLIB_INFLATE">/dev/null 2>&1; then
modprobe -r "$KMOD_ZLIB_INFLATE" >/dev/null 2>&1
fi
if [ "$VERBOSE" = "yes" ]; then
echo "Successfully unloaded ZFS module stack"
fi
return 0
}
stack_clear() {
STACK_MAX_SIZE=/sys/kernel/debug/tracing/stack_max_size
STACK_TRACER_ENABLED=/proc/sys/kernel/stack_tracer_enabled
if [ -e "$STACK_MAX_SIZE" ]; then
echo 1 >"$STACK_TRACER_ENABLED"
echo 0 >"$STACK_MAX_SIZE"
fi
}
stack_check() {
STACK_MAX_SIZE=/sys/kernel/debug/tracing/stack_max_size
STACK_TRACE=/sys/kernel/debug/tracing/stack_trace
STACK_LIMIT=15362
if [ -e "$STACK_MAX_SIZE" ]; then
STACK_SIZE=$(cat "$STACK_MAX_SIZE")
if [ "$STACK_SIZE" -ge "$STACK_LIMIT" ]; then
echo
echo "Warning: max stack size $STACK_SIZE bytes"
cat "$STACK_TRACE"
fi
fi
}
if [ "$(id -u)" != 0 ]; then
echo "Must run as root"
exit 1
fi
if [ "$UNLOAD" = "yes" ]; then
kill_zed
umount -t zfs -a
stack_check
unload_modules
else
stack_clear
check_modules
load_modules "$@"
udevadm trigger
udevadm settle
fi
exit 0