[PATCH 2/2 v4] fsck.xfs: allow forced repairs using xfs_repair

[Jan Tulak <jtulak@redhat.com>]

The fsck.xfs script did nothing, because xfs doesn't need a fsck to be
run on every unclean shutdown. However, sometimes it may happen that the
root filesystem really requires the usage of xfs_repair and then it is a
hassle. This patch makes the situation a bit easier by detecting forced
checks (/forcefsck or fsck.mode=force), so user can require the repair,
without the repair being run all the time.

Signed-off-by: Jan Tulak <jtulak@redhat.com>

---
I omitted the ", or by running fsck.xfs -f." part, Darrick, because it
works only for non-interactive sessions. Running it manually should do
nothing.

---
Changelog:
v4:
- man page changes
v3:
- too quick with fixing in v2... add line at the end of the file
v2:
- return the "exit 0" at the end

v1:
- test for xfs_repair binary
- run only in non-interactive session
- translate xfs_repair return codes to fsck ones
- run only if the filesystem is not mounted
- add manpage update
---
 fsck/xfs_fsck.sh    | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 man/man8/fsck.xfs.8 |  7 ++++++
 2 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/fsck/xfs_fsck.sh b/fsck/xfs_fsck.sh
index e52969e4..0ec6b049 100755
--- a/fsck/xfs_fsck.sh
+++ b/fsck/xfs_fsck.sh
@@ -3,11 +3,42 @@
 # Copyright (c) 2006 Silicon Graphics, Inc.  All Rights Reserved.
 #
 
+NAME=$0
+
+# get the right return code for fsck
+function repair2fsck_code() {
+	case $1 in
+	0)  return 0 # everything is ok
+		;;
+	1)  echo "$NAME error: xfs_repair could not fix the filesystem." 1>&2
+		return 4 # errors left uncorrected
+		;;
+	2)  echo "$NAME error: The filesystem to be checked must not be mounted." 1>&2
+		return 4 # it should not me mounted during boot, something is wrong
+		;;
+	3)  return 1 # The fs has been fixed
+		;;
+	*)  echo "$NAME error: An unknown return code from xfs_repair '$1'" 1>&2
+		return 4 # something went wrong with xfs_repair
+	esac
+}
+
+function ensure_not_mounted() {
+	local dev=$1
+	mounted=`grep -c "^$dev " /proc/mounts`
+	if [ $mounted -ne 0 ]; then
+		echo "$NAME error: The filesystem to be checked must not be mounted." 1>&2
+		exit 4
+	fi
+}
+
 AUTO=false
-while getopts ":aApy" c
+FORCE=false
+while getopts ":aApyf" c
 do
 	case $c in
 	a|A|p|y)	AUTO=true;;
+	f)      	FORCE=true;;
 	esac
 done
 eval DEV=\${$#}
@@ -15,6 +46,38 @@ if [ ! -e $DEV ]; then
 	echo "$0: $DEV does not exist"
 	exit 8
 fi
+
+# The flag -f is added by systemd/init scripts when /forcefsck file is present
+# or fsck.mode=force is used during boot; an unclean shutdown won't trigger
+# this check, user has to explicitly require a forced fsck.
+# But first of all, test if it is a non-interactive session. Use multiple
+# methods to capture most of the cases:
+# The case for *i* and -n "$PS1" are commonly suggested in bash manual
+# and the -t 0 test checks stdin
+case $- in
+	*i*) FORCE=false ;;
+esac
+if [ -n "$PS1" -o -t 0 ]; then
+	FORCE=false
+fi
+
+if $FORCE; then
+	if [ -f /sbin/xfs_repair ]; then
+		BIN="/sbin/xfs_repair"
+	elif [ -f /usr/sbin/xfs_repair ]; then
+		BIN="/usr/sbin/xfs_repair"
+	else
+		echo "$NAME error: xfs_repair was not found!" 1>&2
+		exit 4
+	fi
+
+	ensure_not_mounted $DEV
+
+	$BIN -e $DEV
+	repair2fsck_code $?
+	exit $?
+fi
+
 if $AUTO; then
 	echo "$0: XFS file system."
 else
diff --git a/man/man8/fsck.xfs.8 b/man/man8/fsck.xfs.8
index ace7252d..08812be8 100644
--- a/man/man8/fsck.xfs.8
+++ b/man/man8/fsck.xfs.8
@@ -21,6 +21,13 @@ If you wish to check the consistency of an XFS filesystem,
 or repair a damaged or corrupt XFS filesystem,
 see
 .BR xfs_repair (8).
+.PP
+However, the system administrator can force
+.B fsck.xfs
+to run
+.BR xfs_repair (8)
+by creating a /forcefsck file or booting the system with
+"fsck.mode=force" on the kernel command line.
 .
 .SH FILES
 .IR /etc/fstab .
-- 
2.15.0