[Libguestfs] [PATCH] Default to IDE when VirtIO isn't available
Matthew Booth
mbooth at redhat.com
Wed Mar 31 13:45:30 UTC 2010
Previously we used SCSI when VirtIO wasn't available. KVM's SCSI support is not
as mature as its IDE support, and SCSI isn't supported at all in RHEV.
---
lib/Sys/VirtV2V/Converter.pm | 50 +++++++++++-------
lib/Sys/VirtV2V/Converter/Linux.pm | 19 ++++---
lib/Sys/VirtV2V/GuestOS/RedHat.pm | 100 ++++++++++++++++++++----------------
3 files changed, 100 insertions(+), 69 deletions(-)
diff --git a/lib/Sys/VirtV2V/Converter.pm b/lib/Sys/VirtV2V/Converter.pm
index 71e94f7..5dc8550 100644
--- a/lib/Sys/VirtV2V/Converter.pm
+++ b/lib/Sys/VirtV2V/Converter.pm
@@ -87,7 +87,7 @@ use constant KVM_XML_NOVIRTIO => "
</os>
<devices>
<disk device='disk'>
- <target bus='scsi'/>
+ <target bus='ide'/>
</disk>
<interface type='network'>
<model type='e1000'/>
@@ -268,51 +268,65 @@ sub _unconfigure_bootloaders
}
}
+sub _suffixcmp
+{
+ my ($a, $b) = @_;
+
+ return 1 if (length($a) > length($b));
+ return -1 if (length($a) < length($b));
+
+ return 1 if ($a gt $b);
+ return -1 if ($a lt $b);
+ return 0;
+}
+
sub _configure_storage
{
my ($dom, $devices, $virtio) = @_;
- my $prefix = $virtio ? 'vd' : 'sd';
+ my $prefix = $virtio ? 'vd' : 'hd';
+
+ my @removed = ();
my $suffix = 'a';
foreach my $device (@$devices) {
my ($target) = $dom->findnodes("/domain/devices/disk[\@device='disk']/".
"target[\@dev='$device']");
- die(user_message(__x("Previously detected drive {drive} is no longer ".
- "present in domain XML: {xml}",
- drive => $device,
- xml => $dom->toString())))
+ die("Previously detected drive $device is no longer present in domain ".
+ "XML: ".$dom->toString())
unless (defined($target));
- $target->setAttribute('bus', $virtio ? 'virtio' : 'scsi');
- $target->setAttribute('dev', $prefix.$suffix);
- $suffix++; # Perl magic means 'z'++ == 'aa'
+ # Don't add more than 4 IDE disks
+ if (!$virtio && _suffixcmp($suffix, 'd') > 0) {
+ push(@removed, "$device(disk)");
+ } else {
+ $target->setAttribute('bus', $virtio ? 'virtio' : 'ide');
+ $target->setAttribute('dev', $prefix.$suffix);
+ $suffix++; # Perl magic means 'z'++ == 'aa'
+ }
}
- # Convert the first 4 CDROM drives to IDE, and remove the rest
- $suffix = 'a';
- my $i = 0;
- my @removed = ();
+ # Convert CD-ROM devices to IDE.
+ $suffix = 'a' if ($virtio);
foreach my $target
($dom->findnodes("/domain/devices/disk[\@device='cdrom']/target"))
{
- if ($i < 4) {
+ if (_suffixcmp($suffix, 'd') <= 0) {
$target->setAttribute('bus', 'ide');
$target->setAttribute('dev', "hd$suffix");
$suffix++;
} else {
- push(@removed, $target->getAttribute('dev'));
+ push(@removed, $target->getAttribute('dev')."(cdrom)");
my $disk = $target->getParentNode();
$disk->getParentNode()->removeChild($disk);
}
- $i++;
}
if (@removed > 0) {
- print user_message(__x("WARNING: Only 4 CDROM drives are supported. ".
- "The following CDROM drives have been removed: ".
+ print user_message(__x("WARNING: Only 4 IDE devices are supported. ".
+ "The following drives have been removed: ".
"{list}",
list => join(' ', @removed)));
}
diff --git a/lib/Sys/VirtV2V/Converter/Linux.pm b/lib/Sys/VirtV2V/Converter/Linux.pm
index 6f49351..3e76762 100644
--- a/lib/Sys/VirtV2V/Converter/Linux.pm
+++ b/lib/Sys/VirtV2V/Converter/Linux.pm
@@ -142,7 +142,7 @@ sub _configure_kernel_modules
# Make a note of whether we've added scsi_hostadapter
# We need this on RHEL 4/virtio because mkinitrd can't detect root on
- # virtio. For simplicity we always ensure this is set.
+ # virtio. For simplicity we always ensure this is set for virtio disks.
my $scsi_hostadapter = 0;
foreach my $module (keys(%$modules)) {
@@ -164,17 +164,22 @@ sub _configure_kernel_modules
$hvs_modules{$module} = 1;
}
- $guestos->update_kernel_module($module,
- $virtio ? "virtio_blk" : "sym53c8xx");
+ if ($virtio) {
+ $guestos->update_kernel_module($module, 'virtio_blk');
+ $scsi_hostadapter = 1;
+ }
- $scsi_hostadapter = 1;
+ # IDE doesn't need scsi_hostadapter
+ else {
+ $guestos->disable_kernel_module($module);
+ }
}
}
# Add an explicit scsi_hostadapter if it wasn't there before
- $guestos->enable_kernel_module('scsi_hostadapter',
- $virtio ? "virtio_blk" : "sym53c8xx")
- unless($scsi_hostadapter);
+ if ($virtio && !$scsi_hostadapter) {
+ $guestos->enable_kernel_module('scsi_hostadapter', 'virtio_blk');
+ }
# Warn if any old-HV specific kernel modules weren't updated
foreach my $module (keys(%hvs_modules)) {
diff --git a/lib/Sys/VirtV2V/GuestOS/RedHat.pm b/lib/Sys/VirtV2V/GuestOS/RedHat.pm
index 3f5d90a..8664c2d 100644
--- a/lib/Sys/VirtV2V/GuestOS/RedHat.pm
+++ b/lib/Sys/VirtV2V/GuestOS/RedHat.pm
@@ -964,54 +964,52 @@ sub remap_block_devices
# same names as used by the guest. However, if the guest is using libata,
# IDE drives could be renamed.
- # Look for IDE and SCSI devices in fstab for the guest
- my %guestif;
- foreach my $spec ($g->aug_match('/files/etc/fstab/*/spec')) {
- my $device = $g->aug_get($spec);
-
- next unless($device =~ m{^/dev/(sd|hd)([a-z]+)});
- $guestif{$1} ||= {};
- $guestif{$1}->{$1.$2} = 1;
+ # Modern distros use libata, and IDE devices are presented as sdX
+ my $libata = 1;
+
+ # RHEL 2, 3 and 4 didn't use libata
+ # RHEL 5 does use libata, but udev rules call IDE devices hdX anyway
+ if ($desc->{distro} eq 'rhel') {
+ if ($desc->{major_version} eq '2' ||
+ $desc->{major_version} eq '3' ||
+ $desc->{major_version} eq '4' ||
+ $desc->{major_version} eq '5')
+ {
+ $libata = 0;
+ }
}
+ # Fedora has used libata since FC7, which is long out of support. We assume
+ # that all Fedora distributions in use use libata.
+
+ if ($libata) {
+ # Look for IDE and SCSI devices in fstab for the guest
+ my %guestif;
+ foreach my $spec ($g->aug_match('/files/etc/fstab/*/spec')) {
+ my $device = $g->aug_get($spec);
+
+ next unless($device =~ m{^/dev/(sd|hd)([a-z]+)});
+ $guestif{$1} ||= {};
+ $guestif{$1}->{$1.$2} = 1;
+ }
- # If fstab contains references to sdX, these could refer to IDE or SCSI
- # devices. Need to look at the domain config for clues.
- if (exists($guestif{sd})) {
- # Look for IDE and SCSI devices from the domain definition
- my %domainif;
- foreach my $device (@$devices) {
- foreach my $type ('hd', 'sd') {
- if ($device =~ m{^$type([a-z]+)}) {
- $domainif{$type} ||= {};
- $domainif{$type}->{$device} = 1;
+ # If fstab contains references to sdX, these could refer to IDE or SCSI
+ # devices. We may need to update them.
+ if (exists($guestif{sd})) {
+ # Look for IDE and SCSI devices from the domain definition
+ my %domainif;
+ foreach my $device (@$devices) {
+ foreach my $type ('hd', 'sd') {
+ if ($device =~ m{^$type([a-z]+)}) {
+ $domainif{$type} ||= {};
+ $domainif{$type}->{$device} = 1;
+ }
}
}
- }
-
- # If domain defines both IDE and SCSI drives, and fstab contains
- # references on sdX, but not hdX, we don't know if the guest is using
- # libata or not. This means that we don't know if sdX in fstab refers
- # to hdX or sdX in the domain. Warn and assume that libata device
- # renaming is not in use.
- if (exists($domainif{hd}) && exists($domainif{sd}) &&
- !exists($guestif{hd}))
- {
- print STDERR user_message(__"WARNING: Unable to determine whether ".
- "sdX devices in /etc/fstab refer to ".
- "IDE or SCSI devices. Assuming they ".
- "refer to SCSI devices. /etc/fstab ".
- "may be incorrect after conversion if ".
- "guest uses libata.");
- }
- # If we've got only IDE devices in the domain, and only sdX devices in
- # fstab, the guest is renaming them.
- elsif (exists($domainif{hd}) && !exists($domainif{sd}) &&
- !exists($guestif{hd}))
- {
my %map;
my $letter = 'a';
+ # IDE drives are presented first
foreach my $old (sort { _drivecmp('hd', $a, $b) }
keys(%{$domainif{hd}}))
{
@@ -1019,10 +1017,16 @@ sub remap_block_devices
$letter++;
}
+ # Followed by SCSI drives
+ foreach my $old (sort { _drivecmp('sd', $a, $b) }
+ keys(%{$domainif{sd}}))
+ {
+ $map{$old} = "sd$letter";
+ $letter++;
+ }
+
map { $_ = $map{$_} } @$devices;
}
-
- # Otherwise we leave it alone
}
# We now assume that $devices contains an ordered list of device names, as
@@ -1030,8 +1034,16 @@ sub remap_block_devices
# device names.
my %map;
- # Everything will be converted to either vdX or sdX
- my $prefix = $virtio ? 'vd' : 'sd';
+ # Everything will be converted to either vdX, sdX or hdX
+ my $prefix;
+ if ($virtio) {
+ $prefix = 'vd';
+ } elsif ($libata) {
+ $prefix = 'sd';
+ } else {
+ $prefix = 'hd'
+ }
+
my $letter = 'a';
foreach my $device (@$devices) {
$map{$device} = $prefix.$letter;
--
1.6.6.1
More information about the Libguestfs
mailing list