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|
eval '(exit $?0)' && eval 'exec perl -wS "$0" ${1+"$@"}'
& eval 'exec perl -wS "$0" $argv:q'
if 0;
# Determine whether two files have the same extents by comparing
# the logical block numbers and lengths from filefrag -v for each.
# Invoke like this:
# This helper function, f, extracts logical block number and lengths.
# f() { awk '/^ *[0-9]/ {printf "%d %d ",$2,NF<5?$NF:$5} END {print ""}'; }
# { filefrag -v j1 | f; filefrag -v j2 | f; } | ./filefrag-extent-compare
use warnings;
use strict;
(my $ME = $0) =~ s|.*/||;
my @line = <>;
my $n_lines = @line;
$n_lines == 2
or die "$ME: expected exactly two input lines; got $n_lines\n";
my @A = split ' ', $line[0];
my @B = split ' ', $line[1];
@A % 2 || @B % 2
and die "$ME: unexpected input: odd number of numbers; expected even\n";
my @a;
my @b;
foreach my $i (0..@A/2-1) { $a[$i] = { L_BLK => $A[2*$i], LEN => $A[2*$i+1] } };
foreach my $i (0..@B/2-1) { $b[$i] = { L_BLK => $B[2*$i], LEN => $B[2*$i+1] } };
# Merge adjacent extents in array E.
sub merge_extents($)
{
my ($e) = @_;
my $i = 0;
while (1)
{
!defined $e->[$i+1]
and last;
$e->[$i]->{L_BLK} + $e->[$i]->{LEN} != $e->[$i+1]->{L_BLK}
and ++$i, next;
$e->[$i]->{LEN} += $e->[$i+1]->{LEN};
# Remove $e->[$i+1]
splice @$e, $i+1, 1;
}
}
merge_extents \@a;
merge_extents \@b;
@a == @b
or die "$ME: extent counts differ, even after adjustment\n";
my $i = 0;
while (defined $a[$i])
{
my $start_match = $a[$i]->{L_BLK} == $b[$i]->{L_BLK};
my $len_match = $a[$i]->{LEN} == $b[$i]->{LEN};
if ( ! ($start_match && ($len_match || $i == (@a - 1))))
{
# On XFS on Linux kernel 2.6.38, it was seen that the size of the
# last extent can vary, and can extend beyond the length of the file.
# So we ignore the length of the last extent, because if the
# file is the wrong length we'll get failures elsewhere.
die "$ME: differing extent:\n"
. " [$i]=$a[$i]->{L_BLK} $a[$i]->{LEN}\n"
. " [$i]=$b[$i]->{L_BLK} $b[$i]->{LEN}\n";
}
$i++;
}
### Setup "GNU" style for perl-mode and cperl-mode.
## Local Variables:
## mode: perl
## perl-indent-level: 2
## perl-continued-statement-offset: 2
## perl-continued-brace-offset: 0
## perl-brace-offset: 0
## perl-brace-imaginary-offset: 0
## perl-label-offset: -2
## perl-extra-newline-before-brace: t
## perl-merge-trailing-else: nil
## End:
|
