blkdebug: Always call read_config()

Move the check whether there actually is a config file into the
read_config() function.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blkdebug: Use command-line in read_config()

Use qemu_config_parse_qdict() to parse the command-line options in
addition to the config file.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block: Allow reference for bdrv_file_open()

Allow specifying a reference to an existing block device (by name) for
bdrv_file_open() instead of a filename and/or options.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block: Pass reference to bdrv_file_open()

With that now being possible, bdrv_open() should try to extract a block
device reference from the options and pass it to bdrv_file_open().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block: Allow block devices without files

blkdebug and blkverify will, in order to retain compatibility, not
support the field "file" implicitly through bdrv_open(). In order to be
able to use those drivers without giving a filename anyway, it is
necessary to be able to have block devices without files implicitly
opened by bdrv_open(). This is the case, if there was neither a file
name, a reference to an existing block device to use as a file nor
options specific to the file.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block: Add bdrv_open_image()

Add a common function for opening images to be used for block drivers
specified through BlockdevRefs in an option QDict. The difference from
bdrv_file_open() is that this function may invoke bdrv_open() instead,
allowing auto-detection of the driver to be used; and second, it
automatically extracts the BlockdevRef from the option QDict.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block: Use bdrv_open_image() in bdrv_open()

Using bdrv_open_image() instead of bdrv_file_open() directly in
bdrv_open() is easier.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block: Allow recursive "file"s

It should be possible to use a format as a driver for a file which in
turn requires another file, i.e., nesting file formats.

Allowing nested file formats results in e.g. qcow2 BlockDriverStates
never being directly passed to bdrv_open_common() from bdrv_file_open(),
but instead being handed through bdrv_open(). This changes the error
message when trying to give a filename to qcow2, i.e. trying to use it
as a driver for the protocol level. Therefore, change the reference
output of I/O test 051 accordingly.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blockdev: Move "file" to legacy_opts

Specifying the image filename through the "file" option is a legacy
option and should not be supported by blockdev-add (in that case, giving
a string for "file" references an existing block device).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blkdebug: Allow command-line file configuration

Introduce the "image" option as an alternative to specifying the image
through the filename.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blkverify: Allow command-line configuration

Introduce the "test" and "raw" options for specifying images.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blkverify: Don't require protocol filename

If the filename is not prefixed by "blkverify:" in
blkverify_parse_filename(), the blkverify driver was not selected
through that protocol prefix, but by an explicit command line (or QMP)
option (like driver=blkverify).

If blkverify_parse_filename() has been called, a filename has been
given. If it is not prefixed, it is probably really just a plain
filename. This is no problem, since we can use it as the test image
filename and rely on the user to specify the raw image filename through
the new corresponding option.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qapi: Add "errno" to the list of polluted words

Using "errno" directly as an identifier results in various syntax
errors; therefore it should be added to the list of polluted words.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qapi: QMP interface for blkdebug and blkverify

Add structures to support blkdebug and blkverify in blockdev-add.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qemu-io: Make filename optional

Giving a filename is actually not essential, since it can be specified
through the options as well - on the contrary: Sometimes a filename must
not be given.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
tests: Add test for qdict_array_split()

Add a test case for qdict_array_split() in tests/check-qdict.c.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
tests: Add test for qdict_flatten()

Add a test case for qdict_flatten() in tests/check-qdict.c. This test
case covers the flattening of subordinate QLists as well.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
iotests: Test new blkdebug/blkverify interface

Add a test for the new blkdebug/blkverify interface.

This test is not written in Python, although it uses QMP. This is
because it invokes the qemu-io HMP command, which outputs errors to
stderr instead of returning them through QMP. Filtering and testing that
output is easier in a shell script than with the Python infrastructure.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
iotests: Test file format nesting

Add a test for nested image formats.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block: fix backing file segfault

When a backing file is opened such that (1) a protocol is directly
used as the block driver and (2) the block driver has bdrv_file_open,
bdrv_open_backing_file segfaults. The problem arises because
bdrv_open_common returns without setting bd->backing_hd->file.

To effect (1), you seem to have to use the -F flag in qemu-img. There
are several block drivers that satisfy (2), such as "file" and "nbd".
Here are some concrete examples:

    #!/bin/bash

    echo Test file format
    ./qemu-img create -f file base.file 1m
    ./qemu-img create -f qcow2 -F file -o backing_file=base.file\
        file-overlay.qcow2
    ./qemu-img convert -O raw file-overlay.qcow2 file-convert.raw

    echo Test nbd format
    SOCK=$PWD/nbd.sock
    ./qemu-img create -f raw base.raw 1m
    ./qemu-nbd -t -k $SOCK base.raw &
    trap "kill $!" EXIT
    while ! test -e $SOCK; do sleep 1; done
    ./qemu-img create -f qcow2 -F nbd -o backing_file=nbd:unix:$SOCK\
        nbd-overlay.qcow2
    ./qemu-img convert -O raw nbd-overlay.qcow2 nbd-convert.raw

Without this patch, the two qemu-img convert commands segfault.

This is a regression that was introduced in v1.7 by
dbecebddfa4932d1c83915bcb9b5ba5984eb91be.

Signed-off-by: Peter Feiner <peter@gridcentric.ca>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>