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Fix #2050: only provide 'conv=sparse' for LvmThin

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LVMPlugin->volume_import (used by storage_migrate on either offline
migration with local disks, or online migration with storage-only
referenced disks) passed 'conv=sparse' to `dd`. This can lead to
data-corruption, if the target volume is not zero-initialized.

dropping the sparse argument completely would fix the problem, but
breaks keeping data sparse for LvmThinPlugin.

This patch moves the dd out into (LVM*) plugin specific sub so that
each can control the parameters.

Steps for reproducing the issue:
* create a cluster with (at least) 2 nodes A and B, with a free
  disk-device (/dev/sdx)
* write a recognizable pattern to /dev/sdx on B:
  `dd if=/dev/zero bs=10M | tr '\000' '\255' | dd of=/dev/sdb bs=10M`
  (would be grateful for alternatives to the dd| tr| dd)
* on both A and B create a lvm-vg (pvcreate, vgcreate)
* add it as _not_ shared storage, which is available on nodes A and B
* create a small guest on A
* fill a file in the guest with zeros
  `dd if=/dev/zero of=/zerofil bs=10M`
* stop the guest, migrate it to B
* start the guest - check that the file `/zerofil` contains `ad`
  instead of `00`

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
This commit is contained in:
Stoiko Ivanov
2019-01-17 16:31:51 +01:00
committed by Thomas Lamprecht
parent a31cb84fd4
commit 4e8de9ad56
2 changed files with 15 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
PVE/Storage/LVMPlugin.pm
View File

@ -620,8 +620,8 @@ sub volume_import {
}
my $file = $class->path($scfg, $volname, $storeid)
or die "internal error: failed to get path to newly allocated volume $volname\n";
run_command(['dd', "of=$file", 'conv=sparse', 'bs=64k'],
input => '<&'.fileno($fh));
$class->volume_import_write($fh, $file);
};
if (my $err = $@) {
eval { $class->free_image($storeid, $scfg, $volname, 0) };
@ -630,4 +630,10 @@ sub volume_import {
}
}
sub volume_import_write {
my ($class, $input_fh, $output_file) = @_;
run_command(['dd', "of=$output_file", 'bs=64k'],
input => '<&'.fileno($input_fh));
}
1;

7
PVE/Storage/LvmThinPlugin.pm
View File

@ -374,4 +374,11 @@ sub volume_has_feature {
return undef;
}
# used in LVMPlugin->volume_import
sub volume_import_write {
my ($class, $input_fh, $output_file) = @_;
run_command(['dd', "of=$output_file", 'conv=sparse', 'bs=64k'],
input => '<&'.fileno($input_fh));
}
1;