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btrbk
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btrbk: build a tree from btrfs volume (for subvolume checks)

pull/30/head
Axel Burri 2014-12-12 10:39:40 +01:00
parent a6017460b2
commit 244303ebdd
1 changed files with 110 additions and 53 deletions
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@ -66,7 +66,7 @@ sub VERSION_MESSAGE
sub HELP_MESSAGE sub HELP_MESSAGE
{ {
print STDERR "usage: $0 [options] <root_volume> <subvol> <dest> [dest...]\n"; print STDERR "usage: $0 [options] <src_root_volume> <subvol> <dest_root_volume> <subvol>\n";
print STDERR "\n"; print STDERR "\n";
print STDERR "options:\n"; print STDERR "options:\n";
print STDERR " -h, --help display this help message\n"; print STDERR " -h, --help display this help message\n";
@ -92,34 +92,20 @@ sub run_cmd($;$)
DEBUG "CMD: $cmd"; DEBUG "CMD: $cmd";
if($always_execute || (not $dryrun)) { if($always_execute || (not $dryrun)) {
$ret = `$cmd`; $ret = `$cmd`;
chomp($ret);
DEBUG "RET: $ret";
die("command execution failed: \"$cmd\"") if($?); die("command execution failed: \"$cmd\"") if($?);
} }
return $ret; return $ret;
} }
sub fetch_subvolume_info($)
{
my $path = shift;
my $ret = run_cmd("/sbin/btrfs subvolume list $path", 1); # TODO: use -r for read-only
# my $ret = 'ID 350 gen 185 top level 349 path _backup_btr_system/root_gentoo.20141130_0
#ID 363 gen 194 top level 349 path _backup_btr_system/kvm.20141130_0
#ID 363 gen 194 top level 349 path boot
#';
my @list;
foreach (split(/\n/, $ret)) {
die("Failed to parse line: \"$_\"") unless(/^ID ([0-9]+) gen ([0-9]+) top level ([0-9]+) path (.+)$/);
push @list, { ID => $1, gen => $2, top_level => $3, path => $4 };
}
return \@list;
}
sub check_vol($$) sub check_vol($$)
{ {
my $root = shift; my $root = shift;
my $vol = shift; my $vol = shift;
die("subvolume info not present: $root") unless(exists($vol_info{$root})); die("subvolume info not present: $root") unless(exists($vol_info{$root}));
foreach (@{$vol_info{$root}}) { foreach (values %{$vol_info{$root}}) {
return 1 if($_->{path} eq $vol); return 1 if($_->{FS_PATH} eq "$root/$vol");
} }
return 0; return 0;
} }
@ -136,6 +122,74 @@ sub check_src($$)
} }
} }
sub check_rootvol($)
{
my $vol = shift;
my $ret = run_cmd("/sbin/btrfs subvolume show $vol", 1);
if($ret eq "$vol is btrfs root") {
DEBUG "rootvol check passed: $vol";
return 1;
}
DEBUG "rootvol check failed: $vol";
return 0;
}
sub btr_tree($)
{
my $vol = shift;
die("btr_tree: \"$vol\" is not btrfs root!") unless(check_rootvol($vol));
my $ret = run_cmd("/sbin/btrfs subvolume list -p -a $vol", 1);
my %tree;
foreach (split(/\n/, $ret))
{
# ID <ID> top level <ID> path <path> where path is the relative path
# of the subvolume to the top level subvolume. The subvolume?s ID may
# be used by the subvolume set-default command, or at mount time via
# the subvolid= option. If -p is given, then parent <ID> is added to
# the output between ID and top level. The parent?s ID may be used at
# mount time via the subvolrootid= option.
die("Failed to parse line: \"$_\"") unless(/^ID ([0-9]+) gen ([0-9]+) parent ([0-9]+) top level ([0-9]+) path (.+)$/);
my %node = ( ID => $1,
gen => $2,
parent => $3,
top_level => $4,
path => $5
);
$tree{$node{ID}} = \%node;
DEBUG "btr_tree: processing subvolid=$node{ID}";
# set FS_PATH
#
# NOTE: these substitutions are only valid if $root is a
# absolute path to a btrfs root volume (mounted with
# subvolumeid=0)
DEBUG "btr_tree: original path: $node{path}";
$node{FS_PATH} = $node{path};
if($node{FS_PATH} =~ s/^<FS_TREE>\///) {
DEBUG "btr_tree: removed <FS_TREE> portion subvolume path: $node{FS_PATH}";
}
$node{SUBVOL_PATH} = $node{FS_PATH};
DEBUG "btr_tree: set SUBVOL_PATH: $node{FS_PATH}";
$node{FS_PATH} = $vol . "/" . $node{FS_PATH};
DEBUG "btr_tree: set FS_PATH: $node{FS_PATH}";
if($node{top_level} != 5)
{
# man btrfs-subvolume:
# Also every btrfs filesystem has a default subvolume as its initially
# top-level subvolume, whose subvolume id is 5(FS_TREE).
# set child/parent node
die unless exists($tree{$node{top_level}});
# $tree{$node{top_level}}->{SUBVOL}->{$node{ID}} = \%node;
$tree{$node{ID}}->{PARENT_NODE} = $tree{$node{top_level}};
}
}
return \%tree;
}
sub snapshot($$) sub snapshot($$)
{ {
my $src = shift; my $src = shift;
@ -152,26 +206,29 @@ sub send_receive($$;$)
run_cmd("/sbin/btrfs send $parent $src | /sbin/btrfs receive ${dst}/"); run_cmd("/sbin/btrfs send $parent $src | /sbin/btrfs receive ${dst}/");
} }
sub get_latest_common($$$) sub get_latest_common($$$$)
{ {
my $vol = shift;
my $sroot = shift; my $sroot = shift;
my $svol = shift;
my $droot = shift; my $droot = shift;
my $dvol = shift;
die("source subvolume info not present: $sroot") unless(exists($vol_info{$sroot})); die("source subvolume info not present: $sroot") unless(exists($vol_info{$sroot}));
die("target subvolume info not present: $droot") unless(exists($vol_info{$droot})); die("target subvolume info not present: $droot") unless(exists($vol_info{$droot}));
my $latest; my $latest;
my @svol_list; my @svol_list;
foreach (@{$vol_info{$sroot}}) { foreach (values %{$vol_info{$sroot}}) {
my $v = $_->{path}; my $v = $_->{SUBVOL_PATH};
next unless($v =~ s/^$src_snapshot_dir\/$vol\./$vol\./); DEBUG "get_latest_common(): checking source volume: $v";
next unless($v =~ s/^$src_snapshot_dir\/$svol\./$svol\./);
DEBUG "get_latest_common(): found source snapshot: $v"; DEBUG "get_latest_common(): found source snapshot: $v";
push @svol_list, $v; push @svol_list, $v;
} }
foreach (@{$vol_info{$droot}}) { foreach (values %{$vol_info{$droot}}) {
my $v = $_->{path}; my $v = $_->{SUBVOL_PATH};
next unless($v =~ /^$vol\./); DEBUG "get_latest_common(): checking dest volume: $v";
next unless($v =~ s/^$dvol\///);
if(grep {$_ eq $v} @svol_list) { if(grep {$_ eq $v} @svol_list) {
DEBUG "get_latest_common(): found matching dest snapshot: $v"; DEBUG "get_latest_common(): found matching dest snapshot: $v";
$latest = $v if((not defined($latest)) || ($latest lt $v)); $latest = $v if((not defined($latest)) || ($latest lt $v));
@ -180,7 +237,7 @@ sub get_latest_common($$$)
DEBUG "get_latest_common(): found non-matching dest snapshot: $v"; DEBUG "get_latest_common(): found non-matching dest snapshot: $v";
} }
} }
die("no common snapshots for \"${vol}.*\" found in \"$sroot/$src_snapshot_dir/\" and \"$droot/\"") unless($latest); die("no common snapshots for \"${svol}.*\" found in \"$sroot/$src_snapshot_dir/\" and \"$droot/$dvol\"") unless($latest);
DEBUG "get_latest_common(): latest common snapshot: $latest"; DEBUG "get_latest_common(): latest common snapshot: $latest";
return $latest; return $latest;
} }
@ -195,9 +252,10 @@ MAIN:
getopts('hivd', \%opts); getopts('hivd', \%opts);
my $sroot = shift @ARGV; my $sroot = shift @ARGV;
my $svol = shift @ARGV; my $svol = shift @ARGV;
my @droot_list = @ARGV; my $droot = shift @ARGV;
my $dvol = shift @ARGV;
if($opts{h} || (not $svol) || (not @droot_list)) { if($opts{h} || (not $dvol)) {
VERSION_MESSAGE(); VERSION_MESSAGE();
HELP_MESSAGE(0); HELP_MESSAGE(0);
exit 0; exit 0;
@ -206,20 +264,23 @@ MAIN:
$verbose = $opts{v} || $dryrun; $verbose = $opts{v} || $dryrun;
my $incremental = $opts{i}; my $incremental = $opts{i};
$sroot =~ s/\/+$//; # sanitize trailing slash $sroot =~ s/\/+$//; # remove trailing slash
$svol =~ s/\/+$//; # sanitize trailing slash $sroot =~ s/^\/+/\//; # sanitize leading slash
$svol =~ s/^\/+//; # sanitize trailing slash $svol =~ s/\/+$//; # remove trailing slash
die("svol contains slashes: $svol") if($svol =~ /\//); $svol =~ s/^\/+//; # remove leading slash
# die("svol contains slashes: $svol") if($svol =~ /\//);
$vol_info{$sroot} = fetch_subvolume_info($sroot); $vol_info{$sroot} = btr_tree($sroot);
$droot =~ s/\/+$//; # remove trailing slash
$droot =~ s/^\/+/\//; # sanitize leading slash
$dvol =~ s/\/+$//; # remove trailing slash
$dvol =~ s/^\/+//; # remove leading slash
die if exists $vol_info{$droot};
$vol_info{$droot} = btr_tree($droot);
foreach (@droot_list) {
s/\/+$//; # sanitize
die if exists $vol_info{$_};
$vol_info{$_} = fetch_subvolume_info($_);
};
DEBUG(Data::Dumper->Dump([\%vol_info], ["vol_info"])); DEBUG(Data::Dumper->Dump([\%vol_info], ["vol_info"]));
my $postfix = '.' . strftime($time_format, localtime); my $postfix = '.' . strftime($time_format, localtime);
my $ssnap = "${src_snapshot_dir}/${svol}${postfix}"; my $ssnap = "${src_snapshot_dir}/${svol}${postfix}";
@ -230,18 +291,14 @@ MAIN:
die("snapshot destination already exists: ${sroot}/${ssnap}") if check_vol($sroot, $ssnap); die("snapshot destination already exists: ${sroot}/${ssnap}") if check_vol($sroot, $ssnap);
snapshot("${sroot}/${svol}", "${sroot}/${ssnap}"); snapshot("${sroot}/${svol}", "${sroot}/${ssnap}");
foreach (@droot_list)
{
my $droot = $_;
die("snapshot already exists at destination: $droot") if(check_vol($droot, "${svol}${postfix}")); die("snapshot already exists at destination: $droot") if(check_vol($droot, "${svol}${postfix}"));
if($incremental) { if($incremental) {
my $parent_snap = $src_snapshot_dir . '/' . get_latest_common($svol, $sroot, $droot); my $parent_snap = $src_snapshot_dir . '/' . get_latest_common($sroot, $svol, $droot, $dvol);
die("snapshot parent source does not exists: ${sroot}/${parent_snap}") unless check_vol($sroot, $parent_snap); die("snapshot parent source does not exists: ${sroot}/${parent_snap}") unless check_vol($sroot, $parent_snap);
send_receive("${sroot}/${ssnap}", $droot, "${sroot}/${parent_snap}"); send_receive("${sroot}/${ssnap}", "${droot}/${dvol}", "${sroot}/${parent_snap}");
} }
else { else {
send_receive("${sroot}/${ssnap}", $droot); send_receive("${sroot}/${ssnap}", "${droot}/${dvol}");
}
} }
} }