#!/usr/bin/perl

#ident "$Id: xfs_chver,v 1.1 1998/06/08 19:39:11 mostek Exp $"
#
# This program works with a device (an XFS file system) and updates
# it's version to set the "extent unwritten version" flag and
# log version.
#
# Unwritten extents are not supported on Linux, so are not allowed
# in this script.
#

use strict;

my($prog, $dev, $version, $progjunk, $equ, $junk, $nver, $agcount, $tmp_file,
	$mod_string, $ag, $count, $all, $rest, $devnum, $d, $usage, $mdev,
	$rootdevno, $mydevno, $ino, $mode, $nlink, $uid, $gid, $save_script,
	$base, @args, %mlist, @devlist, $device, $directory, $type,
	$unwritten, $setlogversion, $logversion);

use File::Basename;

$save_script = 0;
$prog = "xfs_chver";
$usage = "usage:  $prog [-f] [ -l version ] -a\n\t$prog [-f] [ -l version ] devname [devname ...]\n";
$all = 0;
$setlogversion = 0;
$unwritten = 0;

while($_ = $ARGV[0], /^-/) {
	shift;
	if (/^-a$/) {
		$all = 1;
	} elsif (/^-f/) {
		$save_script = 1;
	} elsif (/^-u/) {
		print "Unwritten extents unsupported on Linux.\n";
		printf($usage);
		exit 1;
	} elsif (/^-l/) {
		$setlogversion = 1;
		$logversion = $ARGV[0];
		shift;
		if ($logversion != "1" && $logversion != "2") {
			print "Invalid log version $logversion.  Version must be 1 or 2\n";
			printf($usage);
			exit 1;
		}
	} else {
		printf($usage);
		exit 1;
	}
}

if ($all && $ARGV[0]) {
	printf($usage);
	exit 1;
} elsif ($ARGV[0] eq "" && !$all) {
	printf($usage);
	exit 1;
}

# Default action is to update the 'unwritten' flag
#if ($setlogversion == 0 && $unwritten == 0) {
#	$unwritten = 1;
#}

# Unwritten extents unsupported on Linux, logv2 is experimental
# -No- default action.

if ($setlogversion == 0 && $unwritten == 0) {
	print "No log version specified.\n";
	printf($usage);
	exit 1;
}

#
# if all, build an array of devices that are not mounted and
# are in /etc/fstab.
# otherwise, use the list from ARGV.
#

if ($all) {
	open FSTAB, "/etc/fstab" or
		die("$prog: can't open /etc/fstab\n");
	$devnum = 0;
	while (<FSTAB>) {
		if (!/^#/) {
			($device, $directory, $type, $rest) = split(/\s+/);
			if ($type eq "xfs") {
				$devlist[$devnum] = $device;
				$devnum = $devnum+1;
			}
		}
	}
} else {
	@devlist = @ARGV;
}

($d, $ino, $mode, $nlink, $uid, $gid, $rootdevno, $rest) = stat "/dev/root";

open MTAB, "/etc/mtab" or
	die("$prog: can't open /etc/mtab\n");

while (<MTAB>) {
	($device, $directory, $type, $rest) = split(/\s+/);
	if ($type eq "xfs") {
		$mlist{$device} = 1;
	}
}
close(MTAB);

for($devnum = 0; $devlist[$devnum]; $devnum = $devnum+1) {
	$dev = $devlist[$devnum];
	($d, $ino, $mode, $nlink, $uid, $gid, $mydevno, $rest) =
				stat $dev;

	if (!$save_script && ($mydevno == $rootdevno)) {
		printf("$prog: $dev is root so can't change version.\n");
		printf("$prog: must unmount $dev and change using another root or miniroot.\n");
		next;
	}

	if (!$save_script && $mlist{$dev}) {
		printf("$prog: $dev mounted so can't change version.\n");
		printf("$prog: unmount $dev and try again. Skipping $dev.\n");
		next;
	}

	if (!-e $dev) {
		printf("$prog: $dev does not exist.\n");
		next;
	}

	if (!(-r $dev) && ($save_script)) {
		printf("$prog: can't read $dev. Are you root?\n");
		next;
	}

	if (!$save_script && (!(-r $dev) || !(-w $dev))) {
		printf("$prog: can't read or write $dev to update. Are you root?\n");
		next;
	}

	open CUR_VERSION, "xfs_db -c 'sb 0' -c 'p versionnum' -r $dev |" or
		die("can't exec xfs_db -c 'sb 0' -c 'p versionnum' -r $dev to get version");

	$version = 0;
	while(<CUR_VERSION>) {
		if (/versionnum/) {
			chop;
			($junk, $equ, $version) = split(/ /);
			$version = oct $version;
		} else {
			print("$prog: didn't get versionnum in $dev.");
			print("got: ($_) instead.\n");
			print("$prog: skipping $dev.\n");
			next;
		}
	}
	if ($version == 0) {
		print("$prog: nothing came back from xfs_db for $dev, skipping!\n");
		next;
	}
	close CUR_VERSION;

	if ($version == 1) {
		$nver = 0x0004;
		$nver |= 0x1000
			if ($unwritten);
		$nver |= 0x0400
			if ($setlogversion && $logversion == 2);
	} elsif ($version == 2) {
		$nver = 0x0014;
		$nver |= 0x1000
			if ($unwritten);
		$nver |= 0x0400
			if ($setlogversion && $logversion == 2);
	} elsif ($version == 3) {
		$nver = 0x0034;
		$nver |= 0x1000
			if ($unwritten);
		$nver |= 0x0400
			if ($setlogversion && $logversion == 2);
	} elsif ($version & 0x1000 && $unwritten) {
		printf("$prog: $dev has new format 0x%x. Nothing to do.\n", $version);
		next;
	} else {
		$nver = $version;
		$nver |= 0x1000
			if ($unwritten);
		$nver |= 0x0400
			if ($setlogversion && $logversion == 2);
		$nver &= ~0x400
			if ($setlogversion && $logversion == 1);
	}

	open AG, "xfs_db -c 'sb 0' -c 'p agcount' -r $dev |" or
		 die("can't exec xfs_db -c 'sb 0' -c 'p agcount' -r $dev to get agcount\n");

	$agcount = -1;
	while(<AG>) {
		if (/agcount/) {
			chop;
			($junk, $equ, $agcount) = split(/ /);
		} else {
			print("$prog: didn't get agcount in $dev, got: $_ instead\n");
			print("$prog: skipping $dev\n");
			next;
		}
	}

	if ($agcount == -1) {
		print("nothing came back from xfs_db for agcount, quitting!\n");
		print("$prog: NO agcount in $dev, skipping.\n");
		next;
	}
	close AG;

	if (!$save_script) {
		printf("$prog: $dev: changing version 0x%x to 0x%x in $agcount AGs\n",
			$version, $nver, $agcount);
	}

	#
	# Tried to do the following by writing directly to xfs_db. It wouldn't work
	# for some reason eventhough cat, and other programs would see
	# all the commands. For some reason, we need to put the commands
	# in a temp file and read it back in.
	# Would like to do the following but it doesn't work.
	#open(MODIFY, "| xfs_db -x $dev ") or die("can't exec xfs_db -x $dev to fix versions\n");
	#

	$tmp_file = "/tmp/xfs_db.in$$";

	open(TMPFILE, ">$tmp_file") or die("can't create $tmp_file");

	$mod_string = "";
	for ($ag = 0; $ag < $agcount; $ag = $ag + 1) {
		$mod_string .= sprintf("sb $ag\nwrite versionnum 0x%x\n", $nver);
	}
	print(TMPFILE "$mod_string");
	close TMPFILE;

	if ($save_script) {
		$base = basename($dev);
		$base .= ".xfs_chver";
		@args = ("mv", "$tmp_file", "$base");
		system(@args) == 0 or die("$prog: can't save $tmp_file in $base\n");
		printf("$prog: run \"xfs_db -x $dev < $base\"\n");
	} else {
		open(MODIFY, "xfs_db -x $dev < $tmp_file |") or
			die("can't exec xfs_db -x $dev < $tmp_file to fix versions\n");

		while(<MODIFY>) {
			if (/versionnum = /) {
				$count = $count + 1;
			} elsif (!/xfs_db:/) {
				printf("$prog: got $_ back from xfs_db, continue.\n");
			}
		}

		if ($count != $agcount) {
			printf("$prog: WARNING: $count updated instead of $agcount?\n");
			printf("$prog: see $tmp_file for input to xfs_db -x $dev.\n");
			next;
		} else {
			@args = ("rm", "$tmp_file");
			system(@args) == 0 or die("$prog: can't remove $tmp_file\n");
		}
		close MODIFY;
		$count = 0;
	}
}
exit 0;