From bc072c78f6c91bf4e97c205ea56fdef86ab10850 Mon Sep 17 00:00:00 2001
From: Vitaliy Filippov <vitalif@yourcmc.ru>
Date: Thu, 28 Jun 2018 19:20:32 +0300
Subject: [PATCH] Initial commit (with hardcode)

---
 check-fsync-read.pl  | 49 ++++++++++++++++++++++++++++++++++++++++
 check-fsync-write.pl | 53 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+)
 create mode 100644 check-fsync-read.pl
 create mode 100644 check-fsync-write.pl

diff --git a/check-fsync-read.pl b/check-fsync-read.pl
new file mode 100644
index 0000000..9e1042e
--- /dev/null
+++ b/check-fsync-read.pl
@@ -0,0 +1,49 @@
+#!/usr/bin/perl
+
+use strict;
+use File::Sync qw(fsync);
+use Fcntl qw(:DEFAULT O_ASYNC O_DIRECT);
+
+my $device = $ARGV[0];
+my $logfn = $ARGV[1];
+if (!$logfn)
+{
+    print "USAGE: perl r20.pl DEVICE LOGFILE\n";
+    exit;
+}
+
+my $last = {};
+my $logfd;
+open $logfd, $logfn or die $!;
+my $i = 0;
+while (my $s = <$logfd>)
+{
+    $s =~ s/[\x0d\x0a]+$//;
+    my ($pos, $hex) = split / /, $s, 2;
+    $last->{$pos} = $i++;
+}
+
+my $fd;
+sysopen $fd, $device, O_RDONLY or die $!;
+my $buffer = " " x 4096;
+my $fact;
+$i = 0;
+seek $logfd, 0, 0 or die $!;
+while (my $s = <$logfd>)
+{
+    $s =~ s/[\x0d\x0a]+$//;
+    my ($pos, $hex) = split / /, $s, 2;
+    next if $last->{$pos} != $i; # only check last overwrite
+    $hex = pack("H*", $hex);
+    substr($buffer, 0, 4096, ($hex x 512));
+    sysseek($fd, $pos*4096, 0) or die $!;
+    sysread($fd, $fact, 4096) or die $!;
+    if ($fact ne $buffer)
+    {
+        print "Mismatch at offset $pos*4096 (line $i): ".unpack("H*", substr($fact, 0, 8))." vs ".unpack("H*", $hex)."\n";
+    }
+    $i++;
+}
+close $fd;
+
+close $logfd;
diff --git a/check-fsync-write.pl b/check-fsync-write.pl
new file mode 100644
index 0000000..92730f7
--- /dev/null
+++ b/check-fsync-write.pl
@@ -0,0 +1,53 @@
+#!/usr/bin/perl
+# Idea:
+# - run `nc -l 6777 > logfile.txt` on your machine
+# - run `perl check-fsync-write.pl` on tested machine
+# - pull power plug out from tested machine (do not press RESET! pull the plug out!)
+# - power it back on
+# - copy logfile.txt to tested machine
+# - run `perl check-fsync-read.pl /dev/sdX logfile.txt` and check the output
+
+use strict;
+use Socket qw(PF_INET SOCK_STREAM pack_sockaddr_in inet_aton);
+use File::Sync qw(fsync);
+use Fcntl qw(:DEFAULT O_ASYNC O_DIRECT);
+
+# Parameters
+my $diskpath = "/dev/sdf"; # device
+my $disksize = 499896320/8; # (device size / 4096)
+my $ip = '172.29.1.109'; # logger machine IP
+my $port = 6777; # logger machine port
+
+# Code
+my $bufsize = 4096;
+my $align = 512;
+my $buffer = ' ' x ($align+$bufsize);
+my $off = unpack("J", pack "p", $buffer) % $align;
+$off = $align - $off if $off;
+
+my $socket;
+socket $socket, PF_INET, SOCK_STREAM, 0 or die $!;
+connect $socket, pack_sockaddr_in($port, inet_aton($ip)) or die $!;
+
+my $randfd;
+open $randfd, "/dev/urandom" or die $!;
+
+my $fd;
+sysopen $fd, $diskpath, O_WRONLY|O_DIRECT, 0666 or die $!;
+while (1)
+{
+    my $pos;
+    my $number;
+    read $randfd, $pos, 4 or die $!;
+    read $randfd, $number, 8 or die $!;
+    substr($buffer, $off, 4096, $number x 512);
+    $pos = int(1.0 * ($disksize-1) * (unpack("V", $pos) & 0x7fffffff) / 0x7fffffff);
+    sysseek($fd, $pos*4096, 0) or die $!;
+    syswrite($fd, $buffer, 4096, $off) or die $!;
+    fsync($fd);
+    my $s = "$pos ".unpack("H*", $number)."\x0d\x0a";
+    syswrite($socket, $s, length $s) or die $!;
+}
+close $fd;
+
+close $randfd;