...But only if we have the backing_filename. It means something Scary
happened and we can't really be quite exactly sure if we can trust the
backing_filename.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1450122916-4706-5-git-send-email-jsnow@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Add an opaque value which is to be passed to the bdrv_amend_options()
status callback.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add reference count to block job, meanwhile move the ownership of the
reference to job->bs from the caller (which is released in two
completion callbacks) to the block job itself. It is necessary for
block_job_complete_sync to work, because block job shouldn't live longer
than its bs, as asserted in bdrv_delete.
Now block_job_complete_sync can be simplified.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1446765200-3054-6-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The mirror job doesn't update its total length until
it has already started running, so we should translate
a zero-length job-len as meaning 0%.
Otherwise, we may get divide-by-zero faults.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This cleans up the mess we left behind in the mirror code after the
previous patch. Instead of using bdrv_swap(), just change pointers.
The interface change of the mirror job that callers must consider is
that after job completion, their local BDS pointers still point to the
same node now. qemu-img must change its code accordingly (which makes it
easier to understand); the other callers stays unchanged because after
completion they don't do anything with the BDS, but just with the job,
and the job is still owned by the source BDS.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
This is the final step in converting all of the BlockDriverState
pointers that block drivers use to BdrvChild.
After this patch, bs->children contains the full list of child nodes
that are referenced by a given BDS, and these children are only
referenced through BdrvChild, so that updating the pointer in there is
enough for changing edges in the graph.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Not only it makes sense, but it gets rid of checkpatch warning:
WARNING: consider using qemu_strtosz in preference to strtosz
Also remove get rid of tabs to please checkpatch.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1442419377-9309-1-git-send-email-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Example:
$ ./qemu-img create -f qcow2 /tmp/t.qcow2 64M
$ ./qemu-img amend -f qcow2 -o backing_file=/tmp/t.qcow2, -o help \
/tmp/t.qcow2
This should not crash. This actually is tested by iotest 082, but not
caught due to the segmentation fault being silent (which is something
that needs to be fixed, too).
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: qemu-stable <qemu-stable@nongnu.org>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In particular, don't include it into headers.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
These macros expand into error class enumeration constant, comma,
string. Unclean. Has been that way since commit 13f59ae.
The error class is always ERROR_CLASS_GENERIC_ERROR since the previous
commit.
Clean up as follows:
* Prepend every use of a QERR_ macro by ERROR_CLASS_GENERIC_ERROR, and
delete it from the QERR_ macro. No change after preprocessing.
* Rewrite error_set(ERROR_CLASS_GENERIC_ERROR, ...) into
error_setg(...). Again, no change after preprocessing.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
qerror_report_err() is a transitional interface to help with
converting existing monitor commands to QMP. It should not be used
elsewhere.
The only remaining user in qemu-option.c is qemu_opts_parse(). Is it
used in QMP context? If not, we can simply replace
qerror_report_err() by error_report_err().
The uses in qemu-img.c, qemu-io.c, qemu-nbd.c and under tests/ are
clearly not in QMP context.
The uses in vl.c aren't either, because the only QMP command handlers
there are qmp_query_status() and qmp_query_machines(), and they don't
call it.
Remaining uses:
* drive_def(): Command line -drive and such, HMP drive_add and pci_add
* hmp_chardev_add(): HMP chardev-add
* monitor_parse_command(): HMP core
* tmp_config_parse(): Command line -tpmdev
* net_host_device_add(): HMP host_net_add
* net_client_parse(): Command line -net and -netdev
* qemu_global_option(): Command line -global
* vnc_parse_func(): Command line -display, -vnc, default display, HMP
change, QMP change. Bummer.
* qemu_pci_hot_add_nic(): HMP pci_add
* usb_net_init(): Command line -usbdevice, HMP usb_add
Propagate errors through qemu_opts_parse(). Create a convenience
function qemu_opts_parse_noisily() that passes errors to
error_report_err(). Switch all non-QMP users outside tests to it.
That leaves vnc_parse_func(). Propagate errors through it. Since I'm
touching it anyway, rename it to vnc_parse().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
The qemu-img.c file has a read_password() method impl that is
used to prompt for passwords on the console, with impls for
POSIX and Windows. This will be needed by qemu-io.c too, so
move it into the QEMU osdep/oslib files where it can be shared
without code duplication
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The implementation of qemu-img convert is (a) messy, (b) buggy, and
(c) less efficient than possible. The changes required to beat some
sense into it are massive enough that incremental changes would only
make my and the reviewers' life harder. So throw it away and reimplement
it from scratch.
Let me give some examples what I mean by messy, buggy and inefficient:
(a) The copying logic of qemu-img convert has two separate branches for
compressed and normal target images, which roughly do the same -
except for a little code that handles actual differences between
compressed and uncompressed images, and much more code that
implements just a different set of optimisations and bugs. This is
unnecessary code duplication, and makes the code for compressed
output (unsurprisingly) suffer from bitrot.
The code for uncompressed ouput is run twice to count the the total
length for the progress bar. In the first run it just takes a
shortcut and runs only half the loop, and when it's done, it toggles
a boolean, jumps out of the loop with a backwards goto and starts
over. Works, but pretty is something different.
(b) Converting while keeping a backing file (-B option) is broken in
several ways. This includes not writing to the image file if the
input has zero clusters or data filled with zeros (ignoring that the
backing file will be visible instead).
It also doesn't correctly limit every iteration of the copy loop to
sectors of the same status so that too many sectors may be copied to
in the target image. For -B this gives an unexpected result, for
other images it just does more work than necessary.
Conversion with a compressed target completely ignores any target
backing file.
(c) qemu-img convert skips reading and writing an area if it knows from
metadata that copying isn't needed (except for the bug mentioned
above that ignores a status change in some cases). It does, however,
read from the source even if it knows that it will read zeros, and
then search for non-zero bytes in the read buffer, if it's possible
that a write might be needed.
This reimplementation of the copying core reorganises the code to remove
the duplication and have a much more obvious code flow, by essentially
splitting the copy iteration loop into three parts:
1. Find the number of contiguous sectors of the same status at the
current offset (This can also be called in a separate loop before the
copying loop in order to determine the total sectors for the progress
bar.)
2. Read sectors. If the status implies that there is no data there to
read (zero or unallocated cluster), don't do anything.
3. Write sectors depending on the status. If it's data, write it. If
we want the backing file to be visible (with -B), don't write it. If
it's zeroed, skip it if you can, otherwise use bdrv_write_zeroes() to
optimise the write at least where possible.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
qerror_report_err() is a transitional interface to help with
converting existing monitor commands to QMP. It should not be used
elsewhere. Replace by error_report_err().
Commit 6936f29 cleaned that up in qemu-img.c, but two calls have crept
in since. Take care of them the same way.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
man gcc:
Warn about logical not used on the left hand side operand of a
comparison. This option does not warn if the RHS operand is of a
boolean type.
By preferring bool over int where sensible, but without modifying any
depending code, make GCC happy in cases like this,
qemu-img.c: In function ‘compare_sectors’:
qemu-img.c:992:39: error: logical not is only applied to the left hand
side of comparison [-Werror=logical-not-parentheses]
if (!!memcmp(buf1, buf2, 512) != res) {
hw/ide/core.c:1836 doesn't throw an error,
assert(!!s->error == !!(s->status & ERR_STAT));
even thought the second operand is int (and first hunk of this patch has
a very similar case), maybe GCC developers still have a little faith in
C programmers.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
img_convert() and img_amend() use qemu_opts_do_parse(), which reports
errors with qerror_report_err(). Its error messages aren't helpful
here, the caller reports one that actually makes sense. Reproducer:
$ qemu-img convert -o backing_format=raw in.img out.img
qemu-img: Invalid parameter 'backing_format'
qemu-img: Invalid options for file format 'raw'
To fix, propagate errors through qemu_opts_do_parse(). This lifts the
error reporting into callers. Drop it from img_convert() and
img_amend(), keep it in qemu_chr_parse_compat(), bdrv_img_create().
Since I'm touching qemu_opts_do_parse() anyway, write a function
comment for it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
qemu_opt_set() is a wrapper around qemu_opt_set() that reports the
error with qerror_report_err().
Most of its users assume the function can't fail. Make them use
qemu_opt_set_err() with &error_abort, so that should the assumption
ever break, it'll break noisily.
Just two users remain, in util/qemu-config.c. Switch them to
qemu_opt_set_err() as well, then rename qemu_opt_set_err() to
qemu_opt_set().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
add_old_style_options() for img_convert() and img_resize() use
qemu_opt_set(), which reports errors with qerror_report_err(). Its
error messages aren't helpful here, the caller reports one that
actually makes sense. Reproducer:
$ qemu-img convert -B raw in.img out.img
qemu-img: Invalid parameter 'backing_file'
qemu-img: Backing file not supported for file format 'raw'
Switch to qemu_opt_set_err() to get rid of the unwanted messages.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Return the Error object instead of reporting it with
qerror_report_err().
Change callers that assume the function can't fail to pass
&error_abort, so that should the assumption ever break, it'll break
noisily.
Turns out all callers outside its unit test assume that. We could
drop the Error ** argument, but that would make the interface less
regular, so don't.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
qerror_report_err() is a transitional interface to help with
converting existing monitor commands to QMP. It should not be used
elsewhere. Replace by error_report_err().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Although qemu-img already creates BlockBackends, it does not do accesses
to the images through them. This patch converts all of the bdrv_* calls
for which this is currently possible to blk_* calls. Most of the
remaining calls will probably stay bdrv_* calls because they really do
operate on the BDS level instead of the BB level.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1423162705-32065-10-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1423162705-32065-9-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1423162705-32065-8-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The argument given to bdrv_find_protocol() is just a file name, which
makes it difficult for the caller to reconstruct what protocol
bdrv_find_protocol() was hoping to find. This patch adds an Error
parameter to that function to solve this issue.
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1423162705-32065-4-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
If -n is specified, it does not matter whether the output format and
protocol support image creation; building the creation options should
simply be skipped.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1423666727-20777-2-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This is the same way vl.c handles this.
Signed-off-by: Don Slutz <dslutz@verizon.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The string field entries 'filename', 'backing_file', and
'exact_filename' in the BlockDriverState struct are defined as 1024
bytes.
However, many places that use these values accept a maximum of PATH_MAX
bytes, so we have a mixture of 1024 byte and PATH_MAX byte allocations.
This patch makes the BlockDriverStruct field string sizes match usage.
This patch also does a few fixes related to the size that needs to
happen now:
* the block qapi driver is updated to use PATH_MAX bytes
* the qcow and qcow2 drivers have an additional safety check
* the block vvfat driver is updated to use PATH_MAX bytes
for the size of backing_file, for systems where PATH_MAX is < 1024
bytes.
* qemu-img uses PATH_MAX rather than 1024. These instances were not
changed to be dynamically allocated, however, as the extra
temporary 3K in stack usage for qemu-img does not seem worrisome.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The image options which can be amended are described by the .create_opts
field for every driver. This field must therefore be non-NULL so that
anything can be amended in the first place. Check that this holds true
before going into qemu_opts_create() (because if .create_opts is NULL,
the create_opts pointer in img_amend() will be NULL after
qemu_opts_append()).
Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If a driver supports image creation, it needs to set the .create_opts
field. We can use that to make sure .create_opts for both drivers
involved is not NULL for the target image in qemu-img convert, which is
important so that the create_opts pointer in img_convert() is not NULL
after the qemu_opts_append() calls and when going into
qemu_opts_create().
Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
img_open() already prints an error if the operation failed, so there
should not be another error_report() afterwards.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
As soon as options is set in img_amend(), it needs to be freed before
the function returns. This leak is rather insignificant, as qemu-img
will exit subsequently anyway, but there's no point in not fixing it.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Message-id: 1414404776-4919-4-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Now that bdrv_amend_options() supports a status callback, use it to
display a progress report.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1414404776-4919-3-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Depending on the changed options and the image format,
bdrv_amend_options() may take a significant amount of time. In these
cases, a way to be informed about the operation's status is desirable.
Since the operation is rather complex and may fundamentally change the
image, implementing it as AIO or a coroutine does not seem feasible. On
the other hand, implementing it as a block job would be significantly
more difficult than a simple callback and would not add benefits other
than progress report to the amending operation, because it should not
actually be run as a block job at all.
A callback may not be very pretty, but it's very easy to implement and
perfectly fits its purpose here.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1414404776-4919-2-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Introduce a new parameter for qemu-img commit which may be used to
explicitly specify the backing file into which an image should be
committed if the backing chain has more than a single layer.
[Applied Eric Blake's qemu-img.texi documentation rewording
--Stefan]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1414159063-25977-12-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Implement progress output for the commit command by querying the
progress of the block job.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1414159063-25977-11-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
After the top image has been committed, it should be emptied unless
specified otherwise.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1414159063-25977-10-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
qemu-img should use QMP commands whenever possible in order to ensure
feature completeness of both online and offline image operations. As
qemu-img itself has no access to QMP (since this would basically require
just everything being linked into qemu-img), imitate QMP's
implementation of block-commit by using commit_active_start() and then
waiting for the block job to finish.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1414159063-25977-9-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Currently, if bdrv_check() fails either by returning -errno or having
check_errors set, qemu-img check just exits with 1 after having told the
user that there were no errors on the image. This is bad.
Instead of printing the check result if there were internal errors which
were so bad that bdrv_check() could not even complete with 0 as a return
value, qemu-img check should inform the user about the error.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
On BlockBackend destruction, unref its BlockDriverState. Replaces the
callers' unrefs.
This turns the pointer from BlockBackend to BlockDriverState into a
strong reference, managed with bdrv_ref() / bdrv_unref(). The
back-pointer remains weak.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Convenience function blk_new_with_bs() creates a BlockBackend with its
BlockDriverState. Callers have to unref both. The commit after next
will relieve them of the need to unref the BlockDriverState.
Complication: due to the silly way drive_del works, we need a way to
hide a BlockBackend, just like bdrv_make_anon(). To emphasize its
"special" status, give the function a suitably off-putting name:
blk_hide_on_behalf_of_do_drive_del(). Unfortunately, hiding turns the
BlockBackend's name into the empty string. Can't avoid that without
breaking the blk->bs->device_name equals blk->name invariant.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
A block device consists of a frontend device model and a backend.
A block backend has a tree of block drivers doing the actual work.
The tree is managed by the block layer.
We currently use a single abstraction BlockDriverState both for tree
nodes and the backend as a whole. Drawbacks:
* Its API includes both stuff that makes sense only at the block
backend level (root of the tree) and stuff that's only for use
within the block layer. This makes the API bigger and more complex
than necessary. Moreover, it's not obvious which interfaces are
meant for device models, and which really aren't.
* Since device models keep a reference to their backend, the backend
object can't just be destroyed. But for media change, we need to
replace the tree. Our solution is to make the BlockDriverState
generic, with actual driver state in a separate object, pointed to
by member opaque. That lets us replace the tree by deinitializing
and reinitializing its root. This special need of the root makes
the data structure awkward everywhere in the tree.
The general plan is to separate the APIs into "block backend", for use
by device models, monitor and whatever other code dealing with block
backends, and "block driver", for use by the block layer and whatever
other code (if any) dealing with trees and tree nodes.
Code dealing with block backends, device models in particular, should
become completely oblivious of BlockDriverState. This should let us
clean up both APIs, and the tree data structures.
This commit is a first step. It creates a minimal "block backend"
API: type BlockBackend and functions to create, destroy and find them.
BlockBackend objects are created and destroyed exactly when root
BlockDriverState objects are created and destroyed. "Root" in the
sense of "in bdrv_states". They're not yet used for anything; that'll
come shortly.
A root BlockDriverState is created with bdrv_new_root(), so where to
create a BlockBackend is obvious. Where these roots get destroyed
isn't always as obvious.
It is obvious in qemu-img.c, qemu-io.c and qemu-nbd.c, and in error
paths of blockdev_init(), blk_connect(). That leaves destruction of
objects successfully created by blockdev_init() and blk_connect().
blockdev_init() is used only by drive_new() and qmp_blockdev_add().
Objects created by the latter are currently indestructible (see commit
48f364d "blockdev: Refuse to drive_del something added with
blockdev-add" and commit 2d246f0 "blockdev: Introduce
DriveInfo.enable_auto_del"). Objects created by the former get
destroyed by drive_del().
Objects created by blk_connect() get destroyed by blk_disconnect().
BlockBackend is reference-counted. Its reference count never exceeds
one so far, but that's going to change.
In drive_del(), the BB's reference count is surely one now. The BDS's
reference count is greater than one when something else is holding a
reference, such as a block job. In this case, the BB is destroyed
right away, but the BDS lives on until all extra references get
dropped.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Creating an anonymous BDS can't fail. Make that obvious.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1411999675-14533-1-git-send-email-armbru@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The device_name of a BlockDriverState is currently checked because it is
always used as a QemuOpts ID and qemu_opts_create() checks whether such
IDs are wellformed.
node-name is supposed to share the same namespace, but it isn't checked
currently. This patch adds explicit checks both for device_name and
node-name so that the same rules will still apply even if QemuOpts won't
be used any more at some point.
qemu-img used to use names with spaces in them, which isn't allowed any
more. Replace them with underscores.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
On a system with a low limit of open files the initialization
of the event notifier could fail and QEMU exits without printing any
error information to the user.
The problem can be easily reproduced by enforcing a low limit of open
files and start QEMU with enough I/O threads to hit this limit.
The same problem raises, without the creation of I/O threads, while
QEMU initializes the main event loop by enforcing an even lower limit of
open files.
This commit adds an error message on failure:
# qemu [...] -object iothread,id=iothread0 -object iothread,id=iothread1
qemu: Failed to initialize event notifier: Too many open files in system
Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The source cache option takes the same values as the cache option. The
documentation reads a little strange because it starts with "In contrast
the src_cache option ...". The fact that this is comparing with the
previous documented option (the 'cache' option) is implicit. Readers
may be confused, especially if they jump to src_cache without reading
cache documentation first.
Suggested-by: Jeff Nelson <jenelson@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
