block: New bdrv_nb_sectors()

A call to retrieve the image size converts between bytes and sectors
several times:

* BlockDriver method bdrv_getlength() returns bytes.

* refresh_total_sectors() converts to sectors, rounding up, and stores
  in total_sectors.

* bdrv_getlength() converts total_sectors back to bytes (now rounded
  up to a multiple of the sector size).

* Callers wanting sectors rather bytes convert it right back.
  Example: bdrv_get_geometry().

bdrv_nb_sectors() provides a way to omit the last two conversions.
It's exactly bdrv_getlength() with the conversion to bytes omitted.
It's functionally like bdrv_get_geometry() without its odd error
handling.

Reimplement bdrv_getlength() and bdrv_get_geometry() on top of
bdrv_nb_sectors().

The next patches will convert some users of bdrv_getlength() to
bdrv_nb_sectors().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Use bdrv_nb_sectors() in bdrv_make_zero()

Instead of bdrv_getlength().

Variable target_size is initially in bytes, then changes meaning to
sectors.  Ugh.  Replace by target_sectors.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Use bdrv_nb_sectors() in bdrv_aligned_preadv()

Instead of bdrv_getlength().  Eliminate variable len.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Use bdrv_nb_sectors() in bdrv_co_get_block_status()

Instead of bdrv_getlength().

Replace variables length, length2 by total_sectors, nb_sectors2.
Bonus: use total_sectors instead of the slightly unclean
bs->total_sectors.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Use bdrv_nb_sectors() in img_convert()

Instead of bdrv_getlength().  Replace variable output_length by
output_sectors.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Use bdrv_nb_sectors() where sectors, not bytes are wanted

Instead of bdrv_getlength().

Aside: a few of these callers don't handle errors.  I didn't
investigate whether they should.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Drop superfluous aligning of bdrv_getlength()'s value

It returns a multiple of the sector size.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
qemu-img: Make img_convert() get image size just once per image

Chiefly so I don't have to do the error checking in quadruplicate in
the next commit.  Moreover, replacing the frequently updated
bs_sectors by an array assigned just once makes the code easier to
understand.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Avoid bdrv_get_geometry() where errors should be detected

bdrv_get_geometry() hides errors.  Use bdrv_nb_sectors() or
bdrv_getlength() instead where that's obviously inappropriate.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
docs: Make the recommendation for the backing file name position a requirement

The current version of the qcow2 specification recommends to save the backing
file name in the end of the first cluster. It follows that the backing file
name can be saved somewhere in the image, but the first cluster, which
contradicts the current QEMU implementation.

The patch makes the backing file name required to be placed after the header
extensions in the first image cluster.

Signed-off-by: Maria Kustova <maria.k@catit.be>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
configure: explicitly state version requirements to devel packages

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
xen_disk:  fix possible null-ptr dereference

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
docs/multiple-iothreads.txt: add documentation on IOThread programming

This document explains how IOThreads and the main loop are related,
especially how to write code that can run in an IOThread.  Currently
only virtio-blk-data-plane uses these techniques.  The next obvious
target is virtio-scsi; there has also been work on virtio-net.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
qmp: hide "hotplugged" device property from device-list-properties

The "hotplugged" device property was not reported before commit
f4eb32b590bf58c1c67570775eb78beb09964fad ("qmp: show QOM properties in
device-list-properties").  Fix this difference.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
qdev-monitor: include QOM properties in -device FOO, help output

Update -device FOO,help to include QOM properties in addition to qdev
properties.  Devices are gradually adding more QOM properties that are
not reflected as qdev properties.

It is important to report all device properties since management tools
like libvirt use this information (and device-list-properties QMP) to
detect the presence of QEMU features.

This patch reuses the device-list-properties QMP machinery to avoid code
duplication.

Reported-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Cole Robinson <crobinso@redhat.com>
qemu-iotests: Add data pattern in version3 VMDK sample image in 059

It's possible that we diverge from the specification with our
implementation.  Having a reference image in the test cases may detect
such problems when we introduce a bug that can read what it creates, but
can't handle a real VMDK.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
vmdk: Optimize cluster allocation

This drops the unnecessary bdrv_truncate() from, and also improves,
cluster allocation code path.

Before, when we need a new cluster, get_cluster_offset truncates the
image to bdrv_getlength() + cluster_size, and returns the offset of
added area, i.e. the image length before truncating.

This is not efficient, so it's now rewritten as:

  - Save the extent file length when opening.

  - When allocating cluster, use the saved length as cluster offset.

  - Don't truncate image, because we'll anyway write data there: just
    write any data at the EOF position, in descending priority:

    * New user data (cluster allocation happens in a write request).

    * Filling data in the beginning and/or ending of the new cluster, if
      not covered by user data: either backing file content (COW), or
      zero for standalone images.

One major benifit of this change is, on host mounted NFS images, even
over a fast network, ftruncate is slow (see the example below). This
change significantly speeds up cluster allocation. Comparing by
converting a cirros image (296M) to VMDK on an NFS mount point, over
1Gbe LAN:

    $ time qemu-img convert cirros-0.3.1.img /mnt/a.raw -O vmdk

    Before:
        real    0m21.796s
        user    0m0.130s
        sys     0m0.483s

    After:
        real    0m2.017s
        user    0m0.047s
        sys     0m0.190s

We also get rid of unchecked bdrv_getlength() and bdrv_truncate(), and
get a little more documentation in function comments.

Tested that this passes qemu-iotests for all VMDK subformats.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
qemu-img info: show nocow info

Add nocow info in 'qemu-img info' output to show whether the file
currently has NOCOW flag set or not.

Signed-off-by: Chunyan Liu <cyliu@suse.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Support Archipelago as a QEMU block backend

VM Image on Archipelago volume is specified like this:

file.driver=archipelago,file.volume=<volumename>[,file.mport=<mapperd_port>[,
file.vport=<vlmcd_port>][,file.segment=<segment_name>]]

'archipelago' is the protocol.

'mport' is the port number on which mapperd is listening. This is optional
and if not specified, QEMU will make Archipelago to use the default port.

'vport' is the port number on which vlmcd is listening. This is optional
and if not specified, QEMU will make Archipelago to use the default port.

'segment' is the name of the shared memory segment Archipelago stack is using.
This is optional and if not specified, QEMU will make Archipelago to use the
default value, 'archipelago'.

Examples:

file.driver=archipelago,file.volume=my_vm_volume
file.driver=archipelago,file.volume=my_vm_volume,file.mport=123
file.driver=archipelago,file.volume=my_vm_volume,file.mport=123,
file.vport=1234
file.driver=archipelago,file.volume=my_vm_volume,file.mport=123,
file.vport=1234,file.segment=my_segment

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block/archipelago: Implement bdrv_parse_filename()

VM Image on Archipelago volume can also be specified like this:

file=archipelago:<volumename>[/mport=<mapperd_port>[:vport=<vlmcd_port>][:
segment=<segment_name>]]

Examples:

file=archipelago:my_vm_volume
file=archipelago:my_vm_volume/mport=123
file=archipelago:my_vm_volume/mport=123:vport=1234
file=archipelago:my_vm_volume/mport=123:vport=1234:segment=my_segment

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>