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#============================================================= -*-perl-*- |
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# |
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# BackupPC::PoolWrite package |
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# |
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# DESCRIPTION |
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# |
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# This library defines a BackupPC::PoolWrite class for writing |
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# files to disk that are candidates for pooling. One instance |
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# of this class is used to write each file. The following steps |
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# are executed: |
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# |
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# - As the incoming data arrives, the first 1MB is buffered |
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# in memory so the MD5 digest can be computed. |
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# |
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# - A running comparison against all the candidate pool files |
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# (ie: those with the same MD5 digest, usually at most a single |
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# file) is done as new incoming data arrives. Up to $MaxFiles |
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# simultaneous files can be compared in parallel. This |
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# involves reading and uncompressing one or more pool files. |
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# |
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# - When a pool file no longer matches it is discarded from |
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# the search. If there are more than $MaxFiles candidates, one of |
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# the new candidates is added to the search, first checking |
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# that it matches up to the current point (this requires |
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# re-reading one of the other pool files). |
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# |
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# - When or if no pool files match then the new file is written |
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# to disk. This could occur many MB into the file. We don't |
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# need to buffer all this data in memory since we can copy it |
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# from the last matching pool file, up to the point where it |
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# fully matched. |
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# |
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# - When all the new data is complete, if a pool file exactly |
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# matches then the file is simply created as a hardlink to |
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# the pool file. |
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# |
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# AUTHOR |
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# Craig Barratt <cbarratt@users.sourceforge.net> |
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# |
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# COPYRIGHT |
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# Copyright (C) 2001-2003 Craig Barratt |
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# |
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# This program is free software; you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation; either version 2 of the License, or |
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# (at your option) any later version. |
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# |
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# This program is distributed in the hope that it will be useful, |
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# but WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with this program; if not, write to the Free Software |
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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# |
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#======================================================================== |
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# |
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# Version 2.1.0, released 20 Jun 2004. |
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# |
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# See http://backuppc.sourceforge.net. |
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# |
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#======================================================================== |
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|
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package BackupPC::PoolWrite; |
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|
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use strict; |
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|
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use File::Path; |
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use Digest::MD5; |
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use BackupPC::FileZIO; |
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|
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sub new |
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{ |
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my($class, $bpc, $fileName, $fileSize, $compress) = @_; |
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|
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my $self = bless { |
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fileName => $fileName, |
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fileSize => $fileSize, |
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bpc => $bpc, |
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compress => $compress, |
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nWrite => 0, |
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digest => undef, |
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files => [], |
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fileCnt => -1, |
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fhOut => undef, |
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errors => [], |
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data => "", |
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eof => undef, |
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}, $class; |
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|
| 92 |
$self->{hardLinkMax} = $bpc->ConfValue("HardLinkMax"); |
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|
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# |
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# Always unlink any current file in case it is already linked |
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# |
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unlink($fileName) if ( -f $fileName ); |
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return $self; |
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} |
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|
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my $BufSize = 1048576; # 1MB or 2^20 |
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my $MaxFiles = 20; # max number of compare files open at one time |
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|
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sub write |
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{ |
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my($a, $dataRef) = @_; |
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|
| 108 |
return if ( $a->{eof} ); |
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$a->{data} .= $$dataRef if ( defined($dataRef) ); |
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return if ( length($a->{data}) < $BufSize && defined($dataRef) ); |
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|
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# |
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# Correct the fileSize if it is wrong (rsync might transfer |
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# a file whose length is different to the length sent with the |
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# file list if the file changes between the file list sending |
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# and the file sending). Here we only catch the case where |
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# we haven't computed the digest (ie: we have written no more |
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# than $BufSize). We catch the big file case below. |
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# |
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if ( !defined($dataRef) && !defined($a->{digest}) |
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&& $a->{fileSize} != length($a->{data}) ) { |
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#my $newSize = length($a->{data}); |
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#print("Fixing file size from $a->{fileSize} to $newSize\n"); |
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$a->{fileSize} = length($a->{data}); |
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} |
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|
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if ( !defined($a->{digest}) && length($a->{data}) > 0 ) { |
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# |
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# build a list of all the candidate matching files |
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# |
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my $md5 = Digest::MD5->new; |
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$a->{fileSize} = length($a->{data}) |
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if ( $a->{fileSize} < length($a->{data}) ); |
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$a->{digest} = $a->{bpc}->Buffer2MD5($md5, $a->{fileSize}, \$a->{data}); |
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if ( !defined($a->{base} = $a->{bpc}->MD52Path($a->{digest}, |
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$a->{compress})) ) { |
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push(@{$a->{errors}}, "Unable to get path from '$a->{digest}'" |
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. " for $a->{fileName}\n"); |
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} else { |
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while ( @{$a->{files}} < $MaxFiles ) { |
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my $fh; |
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my $fileName = $a->{fileCnt} < 0 ? $a->{base} |
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: "$a->{base}_$a->{fileCnt}"; |
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last if ( !-f $fileName ); |
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if ( (stat(_))[3] >= $a->{hardLinkMax} |
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|| !defined($fh = BackupPC::FileZIO->open($fileName, 0, |
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$a->{compress})) ) { |
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$a->{fileCnt}++; |
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next; |
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} |
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push(@{$a->{files}}, { |
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name => $fileName, |
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fh => $fh, |
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}); |
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$a->{fileCnt}++; |
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} |
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} |
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# |
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# if there are no candidate files then we must write |
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# the new file to disk |
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# |
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if ( !@{$a->{files}} ) { |
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$a->{fhOut} = BackupPC::FileZIO->open($a->{fileName}, |
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1, $a->{compress}); |
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if ( !defined($a->{fhOut}) ) { |
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push(@{$a->{errors}}, "Unable to open $a->{fileName}" |
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. " for writing\n"); |
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} |
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} |
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} |
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my $dataLen = length($a->{data}); |
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if ( !defined($a->{fhOut}) && length($a->{data}) > 0 ) { |
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# |
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# See if the new chunk of data continues to match the |
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# candidate files. |
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# |
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for ( my $i = 0 ; $i < @{$a->{files}} ; $i++ ) { |
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my($d, $match); |
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my $fileName = $a->{fileCnt} < 0 ? $a->{base} |
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: "$a->{base}_$a->{fileCnt}"; |
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if ( $dataLen > 0 ) { |
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# verify next $dataLen bytes from candidate file |
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my $n = $a->{files}[$i]->{fh}->read(\$d, $dataLen); |
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next if ( $n == $dataLen && $d eq $a->{data} ); |
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} else { |
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# verify candidate file is at EOF |
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my $n = $a->{files}[$i]->{fh}->read(\$d, 100); |
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next if ( $n == 0 ); |
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} |
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#print(" File $a->{files}[$i]->{name} doesn't match\n"); |
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# |
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# this candidate file didn't match. Replace it |
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# with a new candidate file. We have to qualify |
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# any new candidate file by making sure that its |
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# first $a->{nWrite} bytes match, plus the next $dataLen |
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# bytes match $a->{data}. |
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# |
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while ( -f $fileName ) { |
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my $fh; |
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if ( (stat(_))[3] >= $a->{hardLinkMax} |
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|| !defined($fh = BackupPC::FileZIO->open($fileName, 0, |
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$a->{compress})) ) { |
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$a->{fileCnt}++; |
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#print(" Discarding $fileName (open failed)\n"); |
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$fileName = "$a->{base}_$a->{fileCnt}"; |
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next; |
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} |
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if ( !$a->{files}[$i]->{fh}->rewind() ) { |
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push(@{$a->{errors}}, |
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"Unable to rewind $a->{files}[$i]->{name}" |
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. " for compare\n"); |
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} |
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$match = $a->filePartialCompare($a->{files}[$i]->{fh}, $fh, |
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$a->{nWrite}, $dataLen, \$a->{data}); |
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if ( $match ) { |
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$a->{files}[$i]->{fh}->close(); |
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$a->{files}[$i]->{fh} = $fh, |
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$a->{files}[$i]->{name} = $fileName; |
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#print(" Found new candidate $fileName\n"); |
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$a->{fileCnt}++; |
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last; |
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} else { |
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#print(" Discarding $fileName (no match)\n"); |
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} |
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$fh->close(); |
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$a->{fileCnt}++; |
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$fileName = "$a->{base}_$a->{fileCnt}"; |
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} |
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if ( !$match ) { |
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# |
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# We couldn't find another candidate file |
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# |
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if ( @{$a->{files}} == 1 ) { |
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#print(" Exhausted matches, now writing\n"); |
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$a->{fhOut} = BackupPC::FileZIO->open($a->{fileName}, |
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1, $a->{compress}); |
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if ( !defined($a->{fhOut}) ) { |
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push(@{$a->{errors}}, |
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"Unable to open $a->{fileName}" |
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. " for writing\n"); |
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} else { |
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if ( !$a->{files}[$i]->{fh}->rewind() ) { |
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push(@{$a->{errors}}, |
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"Unable to rewind" |
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. " $a->{files}[$i]->{name} for copy\n"); |
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} |
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$a->filePartialCopy($a->{files}[$i]->{fh}, $a->{fhOut}, |
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$a->{nWrite}); |
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} |
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} |
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$a->{files}[$i]->{fh}->close(); |
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splice(@{$a->{files}}, $i, 1); |
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$i--; |
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} |
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} |
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} |
| 257 |
if ( defined($a->{fhOut}) && $dataLen > 0 ) { |
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# |
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# if we are in writing mode then just write the data |
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# |
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my $n = $a->{fhOut}->write(\$a->{data}); |
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if ( $n != $dataLen ) { |
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push(@{$a->{errors}}, "Unable to write $dataLen bytes to" |
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. " $a->{fileName} (got $n)\n"); |
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} |
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} |
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$a->{nWrite} += $dataLen; |
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$a->{data} = ""; |
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return if ( defined($dataRef) ); |
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|
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# |
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# We are at EOF, so finish up |
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# |
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$a->{eof} = 1; |
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|
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# |
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# Make sure the fileSize was correct. See above for comments about |
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# rsync. |
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# |
| 280 |
if ( $a->{nWrite} != $a->{fileSize} ) { |
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# |
| 282 |
# Oops, fileSize was wrong, so our MD5 digest was wrong and our |
| 283 |
# effort to match files likely failed. This is ugly, but our |
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# only choice at this point is to re-write the entire file with |
| 285 |
# the correct length. We need to rename the file, open it for |
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# reading, and then re-write the file with the correct length. |
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# |
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|
| 289 |
#print("Doing big file fixup ($a->{fileSize} != $a->{nWrite})\n"); |
| 290 |
|
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my($fh, $fileName); |
| 292 |
$a->{fileSize} = $a->{nWrite}; |
| 293 |
|
| 294 |
if ( defined($a->{fhOut}) ) { |
| 295 |
if ( $a->{fileName} =~ /(.*)\// ) { |
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$fileName = $1; |
| 297 |
} else { |
| 298 |
$fileName = "."; |
| 299 |
} |
| 300 |
# |
| 301 |
# Find a unique target temporary file name |
| 302 |
# |
| 303 |
my $i = 0; |
| 304 |
while ( -f "$fileName/t$$.$i" ) { |
| 305 |
$i++; |
| 306 |
} |
| 307 |
$fileName = "$fileName/t$$.$i"; |
| 308 |
$a->{fhOut}->close(); |
| 309 |
if ( !rename($a->{fileName}, $fileName) |
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|| !defined($fh = BackupPC::FileZIO->open($fileName, 0, |
| 311 |
$a->{compress})) ) { |
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push(@{$a->{errors}}, "Can't rename $a->{fileName} -> $fileName" |
| 313 |
. " or open during size fixup\n"); |
| 314 |
} |
| 315 |
#print("Using temporary name $fileName\n"); |
| 316 |
} elsif ( defined($a->{files}) && defined($a->{files}[0]) ) { |
| 317 |
# |
| 318 |
# We haven't written anything yet, so just use the |
| 319 |
# compare file to copy from. |
| 320 |
# |
| 321 |
$fh = $a->{files}[0]->{fh}; |
| 322 |
$fh->rewind; |
| 323 |
#print("Using compare file $a->{files}[0]->{name}\n"); |
| 324 |
} |
| 325 |
if ( defined($fh) ) { |
| 326 |
my $poolWrite = BackupPC::PoolWrite->new($a->{bpc}, $a->{fileName}, |
| 327 |
$a->{fileSize}, $a->{compress}); |
| 328 |
my $nRead = 0; |
| 329 |
|
| 330 |
while ( $nRead < $a->{fileSize} ) { |
| 331 |
my $thisRead = $a->{fileSize} - $nRead < $BufSize |
| 332 |
? $a->{fileSize} - $nRead : $BufSize; |
| 333 |
my $data; |
| 334 |
my $n = $fh->read(\$data, $thisRead); |
| 335 |
if ( $n != $thisRead ) { |
| 336 |
push(@{$a->{errors}}, |
| 337 |
"Unable to read $thisRead bytes during resize" |
| 338 |
. " from temp $fileName (got $n)\n"); |
| 339 |
last; |
| 340 |
} |
| 341 |
$poolWrite->write(\$data); |
| 342 |
$nRead += $thisRead; |
| 343 |
} |
| 344 |
$fh->close; |
| 345 |
unlink($fileName) if ( defined($fileName) ); |
| 346 |
if ( @{$a->{errors}} ) { |
| 347 |
$poolWrite->close; |
| 348 |
return (0, $a->{digest}, -s $a->{fileName}, $a->{errors}); |
| 349 |
} else { |
| 350 |
return $poolWrite->close; |
| 351 |
} |
| 352 |
} |
| 353 |
} |
| 354 |
|
| 355 |
# |
| 356 |
# Close the compare files |
| 357 |
# |
| 358 |
foreach my $f ( @{$a->{files}} ) { |
| 359 |
$f->{fh}->close(); |
| 360 |
} |
| 361 |
|
| 362 |
if ( $a->{fileSize} == 0 ) { |
| 363 |
# |
| 364 |
# Simply create an empty file |
| 365 |
# |
| 366 |
local(*OUT); |
| 367 |
if ( !open(OUT, ">", $a->{fileName}) ) { |
| 368 |
push(@{$a->{errors}}, "Can't open $a->{fileName} for empty" |
| 369 |
. " output\n"); |
| 370 |
} else { |
| 371 |
close(OUT); |
| 372 |
} |
| 373 |
return (1, $a->{digest}, -s $a->{fileName}, $a->{errors}); |
| 374 |
} elsif ( defined($a->{fhOut}) ) { |
| 375 |
$a->{fhOut}->close(); |
| 376 |
return (0, $a->{digest}, -s $a->{fileName}, $a->{errors}); |
| 377 |
} else { |
| 378 |
if ( @{$a->{files}} == 0 ) { |
| 379 |
push(@{$a->{errors}}, "Botch, no matches on $a->{fileName}" |
| 380 |
. " ($a->{digest})\n"); |
| 381 |
} elsif ( @{$a->{files}} > 1 ) { |
| 382 |
# |
| 383 |
# This is no longer a real error because $Conf{HardLinkMax} |
| 384 |
# could be hit, thereby creating identical pool files |
| 385 |
# |
| 386 |
#my $str = "Unexpected multiple matches on" |
| 387 |
# . " $a->{fileName} ($a->{digest})\n"; |
| 388 |
#for ( my $i = 0 ; $i < @{$a->{files}} ; $i++ ) { |
| 389 |
# $str .= " -> $a->{files}[$i]->{name}\n"; |
| 390 |
#} |
| 391 |
#push(@{$a->{errors}}, $str); |
| 392 |
} |
| 393 |
#print(" Linking $a->{fileName} to $a->{files}[0]->{name}\n"); |
| 394 |
if ( @{$a->{files}} && !link($a->{files}[0]->{name}, $a->{fileName}) ) { |
| 395 |
push(@{$a->{errors}}, "Can't link $a->{fileName} to" |
| 396 |
. " $a->{files}[0]->{name}\n"); |
| 397 |
} |
| 398 |
return (1, $a->{digest}, -s $a->{fileName}, $a->{errors}); |
| 399 |
} |
| 400 |
} |
| 401 |
|
| 402 |
# |
| 403 |
# Finish writing: pass undef dataRef to write so it can do all |
| 404 |
# the work. Returns a 4 element array: |
| 405 |
# |
| 406 |
# (existingFlag, digestString, outputFileLength, errorList) |
| 407 |
# |
| 408 |
sub close |
| 409 |
{ |
| 410 |
my($a) = @_; |
| 411 |
|
| 412 |
return $a->write(undef); |
| 413 |
} |
| 414 |
|
| 415 |
# |
| 416 |
# Abort a pool write |
| 417 |
# |
| 418 |
sub abort |
| 419 |
{ |
| 420 |
my($a) = @_; |
| 421 |
|
| 422 |
if ( defined($a->{fhOut}) ) { |
| 423 |
$a->{fhOut}->close(); |
| 424 |
unlink($a->{fileName}); |
| 425 |
} |
| 426 |
foreach my $f ( @{$a->{files}} ) { |
| 427 |
$f->{fh}->close(); |
| 428 |
} |
| 429 |
$a->{files} = []; |
| 430 |
} |
| 431 |
|
| 432 |
# |
| 433 |
# Copy $nBytes from files $fhIn to $fhOut. |
| 434 |
# |
| 435 |
sub filePartialCopy |
| 436 |
{ |
| 437 |
my($a, $fhIn, $fhOut, $nBytes) = @_; |
| 438 |
my($nRead); |
| 439 |
|
| 440 |
while ( $nRead < $nBytes ) { |
| 441 |
my $thisRead = $nBytes - $nRead < $BufSize |
| 442 |
? $nBytes - $nRead : $BufSize; |
| 443 |
my $data; |
| 444 |
my $n = $fhIn->read(\$data, $thisRead); |
| 445 |
if ( $n != $thisRead ) { |
| 446 |
push(@{$a->{errors}}, |
| 447 |
"Unable to read $thisRead bytes from " |
| 448 |
. $fhIn->name . " (got $n)\n"); |
| 449 |
return; |
| 450 |
} |
| 451 |
$n = $fhOut->write(\$data, $thisRead); |
| 452 |
if ( $n != $thisRead ) { |
| 453 |
push(@{$a->{errors}}, |
| 454 |
"Unable to write $thisRead bytes to " |
| 455 |
. $fhOut->name . " (got $n)\n"); |
| 456 |
return; |
| 457 |
} |
| 458 |
$nRead += $thisRead; |
| 459 |
} |
| 460 |
} |
| 461 |
|
| 462 |
# |
| 463 |
# Compare $nBytes from files $fh0 and $fh1, and also compare additional |
| 464 |
# $extra bytes from $fh1 to $$extraData. |
| 465 |
# |
| 466 |
sub filePartialCompare |
| 467 |
{ |
| 468 |
my($a, $fh0, $fh1, $nBytes, $extra, $extraData) = @_; |
| 469 |
my($nRead, $n); |
| 470 |
my($data0, $data1); |
| 471 |
|
| 472 |
while ( $nRead < $nBytes ) { |
| 473 |
my $thisRead = $nBytes - $nRead < $BufSize |
| 474 |
? $nBytes - $nRead : $BufSize; |
| 475 |
$n = $fh0->read(\$data0, $thisRead); |
| 476 |
if ( $n != $thisRead ) { |
| 477 |
push(@{$a->{errors}}, "Unable to read $thisRead bytes from " |
| 478 |
. $fh0->name . " (got $n)\n"); |
| 479 |
return; |
| 480 |
} |
| 481 |
$n = $fh1->read(\$data1, $thisRead); |
| 482 |
return 0 if ( $n < $thisRead || $data0 ne $data1 ); |
| 483 |
$nRead += $thisRead; |
| 484 |
} |
| 485 |
if ( $extra > 0 ) { |
| 486 |
# verify additional bytes |
| 487 |
$n = $fh1->read(\$data1, $extra); |
| 488 |
return 0 if ( $n != $extra || $data1 ne $$extraData ); |
| 489 |
} else { |
| 490 |
# verify EOF |
| 491 |
$n = $fh1->read(\$data1, 100); |
| 492 |
return 0 if ( $n != 0 ); |
| 493 |
} |
| 494 |
return 1; |
| 495 |
} |
| 496 |
|
| 497 |
1; |
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