Re: [Qemu-devel] [PATCH v12 14/17] iotests: add simple incremental backup case

[Max Reitz]

On 2015-02-09 at 20:35, John Snow wrote:
> Signed-off-by: John Snow <address@hidden>
> ---
>   tests/qemu-iotests/112        | 120 +++++++++++++++++++++++++++++++++++++++++-
>   tests/qemu-iotests/112.out    |   4 +-
>   tests/qemu-iotests/iotests.py |  18 ++++---
>   3 files changed, 133 insertions(+), 9 deletions(-)
>
> diff --git a/tests/qemu-iotests/112 b/tests/qemu-iotests/112
> index 7985cd1..31431ad 100644
> --- a/tests/qemu-iotests/112
> +++ b/tests/qemu-iotests/112
> @@ -22,18 +22,49 @@
>   
>   import os
>   import iotests
> +from iotests import qemu_img, qemu_io, create_image

Is this really necessary? For me, it works without, too; and if it is 
necessary, shouldn't it be part of patch 13?

>   def io_write_patterns(img, patterns):
>       for pattern in patterns:
>           iotests.qemu_io('-c', 'write -P%s %s %s' % pattern, img)
>   
> +class Bitmap:
> +    def __init__(self, name, node):
> +        self.name = name
> +        self.node = node
> +        self.pattern = os.path.join(iotests.test_dir,
> +                                    '%s.backup.%%s.img' % name)

Shouldn't this be %%i? %%s works for me, but I think %%i might look better.

> +        self.num = 0
> +        self.backups = list()
> +
> +    def new_target(self, num=None):
> +        if num is None:
> +            num = self.num
> +        self.num = num + 1
> +        target = self.pattern % num

I hope nobody has a % in the test path...

Although it does look nice, maybe just self.base = 
os.path.join(iotests.test_dir, '%s.backup.img.' % name) and target = 
self.base + str(num) is more robust (putting the '.img' at the end is a 
bonus).

> +        self.backups.append(target)
> +        return target
> +
> +    def last_target(self):
> +        return self.backups[-1]
> +
> +    def del_target(self):
> +        os.remove(self.backups.pop())
> +        self.num -= 1
> +
> +    def __del__(self):
> +        for backup in self.backups:
> +            try:
> +                os.remove(backup)
> +            except OSError:
> +                pass
>   
>   class TestIncrementalBackup(iotests.QMPTestCase):
>       def setUp(self):
>           self.bitmaps = list()
>           self.files = list()
> -        self.vm = iotests.VM()
> +        self.vm = iotests.VM().add_args(['-S'])

Isn't -machine accel=qtest (which is specified by default) enough?

>           self.test_img = os.path.join(iotests.test_dir, 'base.img')
>           self.full_bak = os.path.join(iotests.test_dir, 'backup.img')
>           self.foo_img = os.path.join(iotests.test_dir, 'foo.bar')
> @@ -58,6 +89,93 @@ class TestIncrementalBackup(iotests.QMPTestCase):
>               iotests.qemu_img('create', '-f', fmt, img, size)
>           self.files.append(img)
>   
> +
> +    def create_full_backup(self, drive='drive0'):
> +        res = self.vm.qmp('drive-backup', device=drive,
> +                          sync='full', format=iotests.imgfmt,
> +                          target=self.full_bak)
> +        self.assert_qmp(res, 'return', {})
> +        self.wait_until_completed(drive)
> +        self.check_full_backup()
> +        self.files.append(self.full_bak)
> +
> +
> +    def check_full_backup(self):
> +        self.assertTrue(iotests.compare_images(self.test_img, self.full_bak))
> +
> +
> +    def add_bitmap(self, name, node='drive0'):
> +        bitmap = Bitmap(name, node)
> +        self.bitmaps.append(bitmap)
> +        result = self.vm.qmp('block-dirty-bitmap-add', node=bitmap.node,
> +                             name=bitmap.name)
> +        self.assert_qmp(result, 'return', {})
> +        return bitmap
> +
> +
> +    def create_incremental(self, bitmap=None, num=None,
> +                           parent=None, parentFormat=None, validate=True):
> +        if bitmap is None:
> +            bitmap = self.bitmaps[-1]
> +
> +        # If this is the first incremental backup for a bitmap,
> +        # use the full backup as a backing image. Otherwise, use
> +        # the last incremental backup.
> +        if parent is None:
> +            if bitmap.num is 0:

Why not == 0?

> +                parent = self.full_bak
> +            else:
> +                parent = self.bitmaps[-1].last_target()

Is this intentional or should this be bitmap.last_target()? In this 
patch, no caller of create_incremental() gives any parameter, so there's 
no difference.

> +
> +        target = bitmap.new_target(num)
> +        self.img_create(target, iotests.imgfmt, parent=parent)
> +
> +        result = self.vm.qmp('drive-backup', device=bitmap.node,
> +                             sync='dirty-bitmap', bitmap=bitmap.name,
> +                             format=iotests.imgfmt, target=target,
> +                             mode='existing')
> +        self.assert_qmp(result, 'return', {})
> +
> +        event = self.wait_until_completed(bitmap.node, check_offset=validate)
> +        if validate:
> +            return self.check_incremental(target)
> +
> +
> +    def check_incremental(self, target=None):
> +        if target is None:
> +            target = self.bitmaps[-1].last_target()
> +        self.assertTrue(iotests.compare_images(self.test_img, target))
> +        return True
> +
> +
> +    def hmp_io_writes(self, drive, patterns):
> +        for pattern in patterns:
> +            self.vm.hmp_qemu_io(drive, 'write -P%s %s %s' % pattern)
> +        self.vm.hmp_qemu_io(drive, 'flush')
> +
> +
> +    # Create a bitmap and full backup before VM execution begins,
> +    # then create a series of incremental backups during execution.
> +    def test_incremental_simple(self):
> +        self.create_full_backup()
> +        self.add_bitmap('bitmap0', 'drive0')
> +        self.vm.hmp('c')

self.vm.qmp('continue') works, too, but as I said above, I think 
accel=qtest should be enough so you may not need this at all.

(I'm saying this because we all know that QMP > HMP (obviously))


So I had some small questions which I think I want to have answers 
before giving an R-b, but the test logic looks good to me.

Max

> +        # Sanity: Create a "hollow" incremental backup
> +        self.create_incremental()
> +        # Three writes: One complete overwrite, one new segment,
> +        # and one partial overlap.
> +        self.hmp_io_writes('drive0', (('0xab', 0, 512),
> +                                      ('0xfe', '16M', '256k'),
> +                                      ('0x64', '32736k', '64k')))
> +        self.create_incremental()
> +        # Three more writes, one of each kind, like above
> +        self.hmp_io_writes('drive0', (('0x9a', 0, 512),
> +                                      ('0x55', '8M', '352k'),
> +                                      ('0x78', '15872k', '1M')))
> +        self.create_incremental()
> +        return True
> +
> +
>       def test_sync_dirty_bitmap_missing(self):
>           self.assert_no_active_block_jobs()
>           self.files.append(self.foo_img)
> diff --git a/tests/qemu-iotests/112.out b/tests/qemu-iotests/112.out
> index fbc63e6..8d7e996 100644
> --- a/tests/qemu-iotests/112.out
> +++ b/tests/qemu-iotests/112.out
> @@ -1,5 +1,5 @@
> -..
> +...
>   ----------------------------------------------------------------------
> -Ran 2 tests
> +Ran 3 tests
>   
>   OK
> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
> index 241b5ee..6bff935 100644
> --- a/tests/qemu-iotests/iotests.py
> +++ b/tests/qemu-iotests/iotests.py
> @@ -88,6 +88,11 @@ class VM(object):
>                        '-display', 'none', '-vga', 'none']
>           self._num_drives = 0
>   
> +    # Add arbitrary arguments to the command-line.
> +    def add_args(self, arglist):
> +        self._args = self._args + arglist
> +        return self
> +
>       # This can be used to add an unused monitor instance.
>       def add_monitor_telnet(self, ip, port):
>           args = 'tcp:%s:%d,server,nowait,telnet' % (ip, port)
> @@ -109,23 +114,24 @@ class VM(object):
>           self._num_drives += 1
>           return self
>   
> +    def hmp(self, args):
> +        return self.qmp('human-monitor-command',
> +                           command_line=args)
> +
>       def pause_drive(self, drive, event=None):
>           '''Pause drive r/w operations'''
>           if not event:
>               self.pause_drive(drive, "read_aio")
>               self.pause_drive(drive, "write_aio")
>               return
> -        self.qmp('human-monitor-command',
> -                    command_line='qemu-io %s "break %s bp_%s"' % (drive, 
> event, drive))
> +        self.hmp('qemu-io %s "break %s bp_%s"' % (drive, event, drive))
>   
>       def resume_drive(self, drive):
> -        self.qmp('human-monitor-command',
> -                    command_line='qemu-io %s "remove_break bp_%s"' % (drive, 
> drive))
> +        self.hmp('qemu-io %s "remove_break bp_%s"' % (drive, drive))
>   
>       def hmp_qemu_io(self, drive, cmd):
>           '''Write to a given drive using an HMP command'''
> -        return self.qmp('human-monitor-command',
> -                        command_line='qemu-io %s "%s"' % (drive, cmd))
> +        return self.hmp('qemu-io %s "%s"' % (drive, cmd))
>   
>       def add_fd(self, fd, fdset, opaque, opts=''):
>           '''Pass a file descriptor to the VM'''