This mask will supplement BdrvChildClass when it comes to what role (or
combination of roles) a child takes for its parent. It consists of
BdrvChildRoleBits values (which is an enum).
Because empty enums are not allowed, let us just start with it filled.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200513110544.176672-5-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This structure nearly only contains parent callbacks for child state
changes. It cannot really reflect a child's role, because different
roles may overlap (as we will see when real roles are introduced), and
because parents can have custom callbacks even when the child fulfills a
standard role.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20200513110544.176672-4-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Right now, all users of bdrv_make_empty() call the BlockDriver method
directly. That is not only bad style, it is also wrong, unless the
caller has a BdrvChild with a WRITE or WRITE_UNCHANGED permission.
(WRITE_UNCHANGED suffices, because callers generally use this function
to clear a node with a backing file after a commit operation.)
Introduce bdrv_make_empty() that verifies that it does.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200429141126.85159-2-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Now that there are no clients of bdrv_has_zero_init_truncate, none of
the drivers need to worry about providing it.
What's more, this eliminates a source of some confusion: a literal
reading of the documentation as written in ceaca56f and implemented in
commit 1dcaf527 claims that a driver which returns 0 for
bdrv_has_zero_init_truncate() must not return 1 for
bdrv_has_zero_init(); this condition was violated for parallels, qcow,
and sometimes for vdi, although in practice it did not matter since
those drivers also lacked .bdrv_co_truncate.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200428202905.770727-10-eblake@redhat.com>
Acked-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Now that block drivers can support flags for .bdrv_co_truncate, expose
the parameter in the node level interfaces bdrv_co_truncate() and
bdrv_truncate().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200424125448.63318-3-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of checking the .bdrv_co_create_opts to see if we need the
fallback, just implement the .bdrv_co_create_opts in the drivers that
need it.
This way we don't break various places that need to know if the
underlying protocol/format really supports image creation, and this way
we still allow some drivers to not support image creation.
Fixes: fd17146cd9
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1816007
Note that technically this driver reverts the image creation fallback
for the vxhs driver since I don't have a means to test it, and IMHO it
is better to leave it not supported as it was prior to generic image
creation patches.
Also drop iscsi_create_opts which was left accidentally.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20200326011218.29230-3-mlevitsk@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
[mreitz: Fixed alignment, and moved bdrv_co_create_opts_simple() and
bdrv_create_opts_simple from block.h into block_int.h]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Using the new 'bdrv_co_delete_file' interface, a pure co_routine function
'bdrv_co_delete_file' inside block.c can can be used in a way similar of
the existing bdrv_create_file to to clean up a created file.
We're creating a pure co_routine because the only caller of
'bdrv_co_delete_file' will be already in co_routine context, thus there
is no need to add all the machinery to check for qemu_in_coroutine() and
create a separated co_routine to do the job.
Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20200130213907.2830642-3-danielhb413@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
When a management application manages node names there's no reason to
recurse into backing images in the output of query-named-block-nodes.
Add a parameter to the command which will return just the top level
structs.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Message-Id: <4470f8c779abc404dcf65e375db195cd91a80651.1579509782.git.pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[mreitz: Fixed coding style]
Signed-off-by: Max Reitz <mreitz@redhat.com>
It no longer has any users.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200218103454.296704-11-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
It is unused now. (And it was ugly because it needed to explore all BDS
chains from the top.)
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200218103454.296704-4-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
It is unused since commit 00e30f0 ("block/backup: use backup-top instead
of write notifiers", 2019-10-01), drop it to simplify the code.
While at it, drop redundant assertions on flags.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1578495356-46219-2-git-send-email-pbonzini@redhat.com
Message-Id: <1578495356-46219-2-git-send-email-pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
We need some way to correlate QAPI BlockPermission values with
BLK_PERM_* flags. We could:
(1) have the same order in the QAPI definition as the the BLK_PERM_*
flags are in LSb-first order. However, then there is no guarantee
that they actually match (e.g. when someone modifies the QAPI schema
without thinking of the BLK_PERM_* definitions).
We could add static assertions, but these would break what’s good
about this solution, namely its simplicity.
(2) define the BLK_PERM_* flags based on the BlockPermission values.
But this way whenever someone were to modify the QAPI order
(perfectly sensible in theory), the BLK_PERM_* values would change.
Because these values are used for file locking, this might break
file locking between different qemu versions.
Therefore, go the slightly more cumbersome way: Add a function to
translate from the QAPI constants to the BLK_PERM_* flags.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20191108123455.39445-2-mreitz@redhat.com
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
We have two drivers (iscsi and file-posix) that (in some cases) return
success from their .bdrv_co_truncate() implementation if the block
device is larger than the requested offset, but cannot be shrunk. Some
callers do not want that behavior, so this patch adds a new parameter
that they can use to turn off that behavior.
This patch just adds the parameter and lets the block/io.c and
block/block-backend.c functions pass it around. All other callers
always pass false and none of the implementations evaluate it, so that
this patch does not change existing behavior. Future patches take care
of that.
Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190918095144.955-5-mreitz@redhat.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
We'll need reverse-foreach in the following commit, QTAILQ support it,
so move to QTAILQ.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190927122355.7344-2-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>
A block driver can provide a callback to report driver-specific
statistics.
file-posix driver now reports discard statistics
Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20190923121737.83281-10-anton.nefedov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Replace confusing usage:
~BDRV_SECTOR_MASK
With more clear:
(BDRV_SECTOR_SIZE - 1)
Remove BDRV_SECTOR_MASK and the unused BDRV_BLOCK_OFFSET_MASK which was
it's last user.
Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Message-id: 20190827185913.27427-3-nsoffer@redhat.com
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
No .bdrv_has_zero_init() implementation returns 1 if growing the file
would add non-zero areas (at least with PREALLOC_MODE_OFF), so using it
in lieu of this new function was always safe.
But on the other hand, it is possible that growing an image that is not
zero-initialized would still add a zero-initialized area, like when
using nonpreallocating truncation on a preallocated image. For callers
that care only about truncation, not about creation with potential
preallocation, this new function is useful.
Alternatively, we could have added a PreallocMode parameter to
bdrv_has_zero_init(). But the only user would have been qemu-img
convert, which does not have a plain PreallocMode value right now -- it
would have to parse the creation option to obtain it. Therefore, the
simpler solution is to let bdrv_has_zero_init() inquire the
preallocation status and add the new bdrv_has_zero_init_truncate() that
presupposes PREALLOC_MODE_OFF.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190724171239.8764-4-mreitz@redhat.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Some of the generated qapi-types-MODULE.h are included all over the
place. Changing a QAPI type can trigger massive recompiling. Top
scorers recompile more than 1000 out of some 6600 objects (not
counting tests and objects that don't depend on qemu/osdep.h):
6300 qapi/qapi-builtin-types.h
5700 qapi/qapi-types-run-state.h
3900 qapi/qapi-types-common.h
3300 qapi/qapi-types-sockets.h
3000 qapi/qapi-types-misc.h
3000 qapi/qapi-types-crypto.h
3000 qapi/qapi-types-job.h
3000 qapi/qapi-types-block-core.h
2800 qapi/qapi-types-block.h
1300 qapi/qapi-types-net.h
Clean up headers to include generated QAPI headers only where needed.
Impact is negligible except for hw/qdev-properties.h.
This header includes qapi/qapi-types-block.h and
qapi/qapi-types-misc.h. They are used only in expansions of property
definition macros such as DEFINE_PROP_BLOCKDEV_ON_ERROR() and
DEFINE_PROP_OFF_AUTO(). Moving their inclusion from
hw/qdev-properties.h to the users of these macros avoids pointless
recompiles. This is how other property definition macros, such as
DEFINE_PROP_NETDEV(), already work.
Improves things for some of the top scorers:
3600 qapi/qapi-types-common.h
2800 qapi/qapi-types-sockets.h
900 qapi/qapi-types-misc.h
2200 qapi/qapi-types-crypto.h
2100 qapi/qapi-types-job.h
2100 qapi/qapi-types-block-core.h
270 qapi/qapi-types-block.h
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190812052359.30071-3-armbru@redhat.com>
Do effective copy-on-read request when we don't need data actually. It
will be used for block-stream and NBD_CMD_CACHE.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190725100550.33801-2-vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[eblake: comment grammar fix]
Signed-off-by: Eric Blake <eblake@redhat.com>
bdrv_set_aio_context_ignore() can only work in the main loop:
bdrv_drained_begin() only works in the main loop and the node's (old)
AioContext; and bdrv_drained_end() really only works in the main loop
and the node's (new) AioContext (contrary to its current comment, which
is just wrong).
Consequentially, bdrv_set_aio_context_ignore() must be called from the
main loop. Luckily, assuming that we can make block graph changes only
from the main loop as well, all its callers do that already.
Note that changing a node's context in a sense is an operation that
changes the block graph, so it actually makes sense to require this
function to be called from the main loop.
Also, fix bdrv_drained_end()'s description. You can only use it from
the main loop or the node's AioContext, and in the latter case, the
whole subtree must be in the same context.
Fixes: e037c09c78
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190722133054.21781-3-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
We should never poll anywhere in bdrv_do_drained_end() (including its
recursive callees like bdrv_drain_invoke()), because it does not cope
well with graph changes. In fact, it has been written based on the
postulation that no graph changes will happen in it.
Instead, the callers that want to poll must poll, i.e. all currently
globally available wrappers: bdrv_drained_end(),
bdrv_subtree_drained_end(), bdrv_unapply_subtree_drain(), and
bdrv_drain_all_end(). Graph changes there do not matter.
They can poll simply by passing a pointer to a drained_end_counter and
wait until it reaches 0.
This patch also adds a non-polling global wrapper for
bdrv_do_drained_end() that takes a drained_end_counter pointer. We need
such a variant because now no function called anywhere from
bdrv_do_drained_end() must poll. This includes
BdrvChildRole.drained_end(), which already must not poll according to
its interface documentation, but bdrv_child_cb_drained_end() just
violates that by invoking bdrv_drained_end() (which does poll).
Therefore, BdrvChildRole.drained_end() must take a *drained_end_counter
parameter, which bdrv_child_cb_drained_end() can pass on to the new
bdrv_drained_end_no_poll() function.
Note that we now have a pattern of all drained_end-related functions
either polling or receiving a *drained_end_counter to let the caller
poll based on that.
A problem with a single poll loop is that when the drained section in
bdrv_set_aio_context_ignore() ends, some nodes in the subgraph may be in
the old contexts, while others are in the new context already. To let
the collective poll in bdrv_drained_end() work correctly, we must not
hold a lock to the old context, so that the old context can make
progress in case it is different from the current context.
(In the process, remove the comment saying that the current context is
always the old context, because it is wrong.)
In all other places, all nodes in a subtree must be in the same context,
so we can just poll that. The exception of course is
bdrv_drain_all_end(), but that always runs in the main context, so we
can just poll NULL (like bdrv_drain_all_begin() does).
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
These functions are not used outside of block/io.c, there is no reason
why they should be globally available.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit 5cb2737e92 laid out why
bdrv_do_drained_end() must decrement the quiesce_counter after
bdrv_drain_invoke(). It did not give a very good reason why it has to
happen after bdrv_parent_drained_end(), instead only claiming symmetry
to bdrv_do_drained_begin().
It turns out that delaying it for so long is wrong.
Situation: We have an active commit job (i.e. a mirror job) from top to
base for the following graph:
filter
|
[file]
|
v
top --[backing]--> base
Now the VM is closed, which results in the job being cancelled and a
bdrv_drain_all() happening pretty much simultaneously.
Beginning the drain means the job is paused once whenever one of its
nodes is quiesced. This is reversed when the drain ends.
With how the code currently is, after base's drain ends (which means
that it will have unpaused the job once), its quiesce_counter remains at
1 while it goes to undrain its parents (bdrv_parent_drained_end()). For
some reason or another, undraining filter causes the job to be kicked
and enter mirror_exit_common(), where it proceeds to invoke
block_job_remove_all_bdrv().
Now base will be detached from the job. Because its quiesce_counter is
still 1, it will unpause the job once more. So in total, undraining
base will unpause the job twice. Eventually, this will lead to the
job's pause_count going negative -- well, it would, were there not an
assertion against this, which crashes qemu.
The general problem is that if in bdrv_parent_drained_end() we undrain
parent A, and then undrain parent B, which then leads to A detaching the
child, bdrv_replace_child_noperm() will undrain A as if we had not done
so yet; that is, one time too many.
It follows that we cannot decrement the quiesce_counter after invoking
bdrv_parent_drained_end().
Unfortunately, decrementing it before bdrv_parent_drained_end() would be
wrong, too. Imagine the above situation in reverse: Undraining A leads
to B detaching the child. If we had already decremented the
quiesce_counter by that point, bdrv_replace_child_noperm() would undrain
B one time too little; because it expects bdrv_parent_drained_end() to
issue this undrain. But bdrv_parent_drained_end() won't do that,
because B is no longer a parent.
Therefore, we have to do something else. This patch opts for
introducing a second quiesce_counter that counts how many times a
child's parent has been quiesced (though c->role->drained_*). With
that, bdrv_replace_child_noperm() just has to undrain the parent exactly
that many times when removing a child, and it will always be right.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch is used in the 'block/stream: introduce a bottom node'
that is following. Instead of the base node, the caller may pass
the node that has the base as its backing image to the function
bdrv_is_allocated_above() with a new parameter include_base = true
and get rid of the dependency on the base that may change during
commit/stream parallel jobs. Now, if the specified base is not
found in the backing image chain, the QEMU will abort.
Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 1559152576-281803-2-git-send-email-andrey.shinkevich@virtuozzo.com
[mreitz: Squashed in the following as a rebase on conflicting patches:]
Message-id: e3cf99ae-62e9-8b6e-5a06-d3c8b9363b85@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This fixes at least one overflow in qcow2_process_discards, which
passes 64bit region length to bdrv_pdiscard where bytes (or sectors in
the past) parameter is int since its introduction in 0b919fae.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
All callers of bdrv_set_aio_context() are eliminated now, they have
moved to bdrv_try_set_aio_context() and related safe functions. Remove
bdrv_set_aio_context().
With this, we can now know that the .set_aio_ctx callback must be
present in bdrv_set_aio_context_ignore() because
bdrv_can_set_aio_context() would have returned false previously, so
instead of checking the condition, we can assert it.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
drv_co_block_status digs bs->file for additional, more accurate search
for hole inside region, reported as DATA by bs since 5daa74a6eb.
This accuracy is not free: assume we have qcow2 disk. Actually, qcow2
knows, where are holes and where is data. But every block_status
request calls lseek additionally. Assume a big disk, full of
data, in any iterative copying block job (or img convert) we'll call
lseek(HOLE) on every iteration, and each of these lseeks will have to
iterate through all metadata up to the end of file. It's obviously
ineffective behavior. And for many scenarios we don't need this lseek
at all.
However, lseek is needed when we have metadata-preallocated image.
So, let's detect metadata-preallocation case and don't dig qcow2's
protocol file in other cases.
The idea is to compare allocation size in POV of filesystem with
allocations size in POV of Qcow2 (by refcounts). If allocation in fs is
significantly lower, consider it as metadata-preallocation case.
102 iotest changed, as our detector can't detect shrinked file as
metadata-preallocation, which don't seem to be wrong, as with metadata
preallocation we always have valid file length.
Two other iotests have a slight change in their QMP output sequence:
Active 'block-commit' returns earlier because the job coroutine yields
earlier on a blocking operation. This operation is loading the refcount
blocks in qcow2_detect_metadata_preallocation().
Suggested-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
All block nodes and users in any connected component of the block graph
must be in the same AioContext, so changing the AioContext of one node
must not only change all of its children, but all of its parents (and
in turn their children etc.) as well.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Eventually, we want to make sure that all parents and all children of a
node are in the same AioContext as the node itself. This means that
changing the AioContext may fail because one of the other involved
parties (e.g. a guest device that was configured with an iothread)
cannot allow switching to a different AioContext.
Introduce a set of functions that allow to first check whether all
involved nodes can switch to a new context and only then do the actual
switch. The check recursively covers children and parents.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
No one is using these functions anymore, all callers have switched to
the byte-based bdrv_pread() and bdrv_pwrite()
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
For qemu-img convert, we want an operation that zeroes out the whole
image if this can be done efficiently, but that returns an error
otherwise so we don't write explicit zeroes and immediately overwrite
them with the real data, potentially doubling the amount of data to be
written.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
This patch allows the user to change the backing file of an image that
is being reopened. Here's what it does:
- In bdrv_reopen_prepare(): check that the value of 'backing' points
to an existing node or is null. If it points to an existing node it
also needs to make sure that replacing the backing file will not
create a cycle in the node graph (i.e. you cannot reach the parent
from the new backing file).
- In bdrv_reopen_commit(): perform the actual node replacement by
calling bdrv_set_backing_hd().
There may be temporary implicit nodes between a BDS and its backing
file (e.g. a commit filter node). In these cases bdrv_reopen_prepare()
looks for the real (non-implicit) backing file and requires that the
'backing' option points to it. Replacing or detaching a backing file
is forbidden if there are implicit nodes in the middle.
Although x-blockdev-reopen is meant to be used like blockdev-add,
there's an important thing that must be taken into account: the only
way to set a new backing file is by using a reference to an existing
node (previously added with e.g. blockdev-add). If 'backing' contains
a dictionary with a new set of options ({"driver": "qcow2", "file": {
... }}) then it is interpreted that the _existing_ backing file must
be reopened with those options.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Children in QMP are specified with BlockdevRef / BlockdevRefOrNull,
which can contain a set of child options, a child reference, or
NULL. In optional attributes like "backing" it can also be missing.
Only the first case (set of child options) is being handled properly
by bdrv_reopen_queue(). This patch deals with all the others.
Here's how these cases should be handled when bdrv_reopen_queue() is
deciding what to do with each child of a BlockDriverState:
1) Set of child options: if the child was implicitly created (i.e
inherits_from points to the parent) then the options are removed
from the parent's options QDict and are passed to the child with
a recursive bdrv_reopen_queue() call. This case was already
working fine.
2) Child reference: there's two possibilites here.
2a) Reference to the current child: if the child was implicitly
created then it is put in the reopen queue, keeping its
current set of options (since this was a child reference
there was no way to specify a different set of options).
If the child is not implicit then it keeps its current set
of options but it is not reopened (and therefore does not
inherit any new option from the parent).
2b) Reference to a different BDS: the current child is not put
in the reopen queue at all. Passing a reference to a
different BDS can be used to replace a child, although at
the moment no driver implements this, so it results in an
error. In any case, the current child is not going to be
reopened (and might in fact disappear if it's replaced)
3) NULL: This is similar to (2b). Although no driver allows this
yet it can be used to detach the current child so it should not
be put in the reopen queue.
4) Missing option: at the moment "backing" is the only case where
this can happen. With "blockdev-add", leaving "backing" out
means that the default backing file is opened. We don't want to
open a new image during reopen, so we require that "backing" is
always present. We'll relax this requirement a bit in the next
patch. If keep_old_opts is true and "backing" is missing then
this behaves like 2a (the current child is reopened).
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The bdrv_reopen_queue() function is used to create a queue with
the BDSs that are going to be reopened and their new options. Once
the queue is ready bdrv_reopen_multiple() is called to perform the
operation.
The original options from each one of the BDSs are kept, with the new
options passed to bdrv_reopen_queue() applied on top of them.
For "x-blockdev-reopen" we want a function that behaves much like
"blockdev-add". We want to ignore the previous set of options so that
only the ones actually specified by the user are applied, with the
rest having their default values.
One of the things that we need is a way to tell bdrv_reopen_queue()
whether we want to keep the old set of options or not, and that's what
this patch does. All current callers are setting this new parameter to
true and x-blockdev-reopen will set it to false.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Our permission system is useful to define what operations are allowed
on a certain block node and includes things like BLK_PERM_WRITE or
BLK_PERM_RESIZE among others.
One of the permissions is BLK_PERM_GRAPH_MOD which allows "changing
the node that this BdrvChild points to". The exact meaning of this has
never been very clear, but it can be understood as "change any of the
links connected to the node". This can be used to prevent changing a
backing link, but it's too coarse.
This patch adds a new 'frozen' attribute to BdrvChild, which forbids
detaching the link from the node it points to, and new API to freeze
and unfreeze a backing chain.
After this change a few functions can fail, so they need additional
checks.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_iterate_format (which is currently only used for printing out the
formats supported by the block layer) doesn't take format whitelisting
into account.
This creates a problem for tests: they enumerate supported formats to
decide which tests to enable, but then discover that QEMU doesn't let
them actually use some of those formats.
To avoid that, exclude formats that are not whitelisted from
enumeration, if whitelisting is in use. Since we have separate
whitelists for r/w and r/o, take this a parameter to
bdrv_iterate_format, and print two lists of supported formats (r/w and
r/o) in main qemu.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function may be implemented by block drivers to derive a directory
name from a BDS. Concatenating this g_free()-able string with a relative
filename must result in a valid (not necessarily existing) filename, so
this is a function that should generally be not implemented by format
drivers, because this is protocol-specific.
If a BDS's driver does not implement this function, bdrv_dirname() will
fall through to the BDS's file if it exists. If it does not, the
exact_filename field will be used to generate a directory name.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20190201192935.18394-15-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Make bdrv_get_full_backing_filename() return an allocated string instead
of placing the result in a caller-provided buffer.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20190201192935.18394-12-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Make bdrv_get_full_backing_filename_from_filename() return an allocated
string instead of placing the result in a caller-provided buffer.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190201192935.18394-11-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Besides being safe for arbitrary path lengths, after some follow-up
patches all callers will want a freshly allocated buffer anyway.
In the meantime, path_combine_deprecated() is added which has the same
interface as path_combine() had before this patch. All callers to that
function will be converted in follow-up patches.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 20190201192935.18394-10-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Before this patch, bdrv_refresh_filename() is used in a pushing manner:
Whenever the BDS graph is modified, the parents of the modified edges
are supposed to be updated (recursively upwards). However, that is
nonviable, considering that we want child changes not to concern
parents.
Also, in the long run we want a pull model anyway: Here, we would have a
bdrv_filename() function which returns a BDS's filename, freshly
constructed.
This patch is an intermediate step. It adds bdrv_refresh_filename()
calls before every place a BDS.filename value is used. The only
exceptions are protocol drivers that use their own filename, which
clearly would not profit from refreshing that filename before.
Also, bdrv_get_encrypted_filename() is removed along the way (as a user
of BDS.filename), since it is completely unused.
In turn, all of the calls to bdrv_refresh_filename() before this patch
are removed, because we no longer have to call this function on graph
changes.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190201192935.18394-2-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Inform a user in case qcow2_get_specific_info fails to obtain
QCOW2 image specific information. This patch is preliminary to
the one "qcow2: Add list of bitmaps to ImageInfoSpecificQCow2".
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <1549638368-530182-2-git-send-email-andrey.shinkevich@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Add a new command, returning block nodes (and their users) graph.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20181221170909.25584-2-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Now that all callers are passing all flag changes as QDict options,
the flags parameter is no longer necessary, so we can get rid of it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
No one is using this function anymore, so we can safely remove it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Most callers of bdrv_reopen() only use it to switch a BlockDriverState
between read-only and read-write, so this patch adds a new function
that does just that.
We also want to get rid of the flags parameter in the bdrv_reopen()
API, so this function sets the "read-only" option and passes the
original flags (which will then be updated in bdrv_reopen_prepare()).
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Some block drivers have traditionally changed their node to read-only
mode without asking the user. This behaviour has been marked deprecated
since 2.11, expecting users to provide an explicit read-only=on option.
Now that we have auto-read-only=on, enable these drivers to make use of
the option.
This is the only use of bdrv_set_read_only(), so we can make it a bit
more specific and turn it into a bdrv_apply_auto_read_only() that is
more convenient for drivers to use.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
If a management application builds the block graph node by node, the
protocol layer doesn't inherit its read-only option from the format
layer any more, so it must be set explicitly.
Backing files should work on read-only storage, but at the same time, a
block job like commit should be able to reopen them read-write if they
are on read-write storage. However, without option inheritance, reopen
only changes the read-only option for the root node (typically the
format layer), but not the protocol layer, so reopening fails (the
format layer wants to get write permissions, but the protocol layer is
still read-only).
A simple workaround for the problem in the management tool would be to
open the protocol layer always read-write and to make only the format
layer read-only for backing files. However, sometimes the file is
actually stored on read-only storage and we don't know whether the image
can be opened read-write (for example, for NBD it depends on the server
we're trying to connect to). This adds an option that makes QEMU try to
open the image read-write, but allows it to degrade to a read-only mode
without returning an error.
The documentation for this option is consciously phrased in a way that
allows QEMU to switch to a better model eventually: Instead of trying
when the image is first opened, making the read-only flag dynamic and
changing it automatically whenever the first BLK_PERM_WRITE user is
attached or the last one is detached would be much more useful
behaviour.
Unfortunately, this more useful behaviour is also a lot harder to
implement, and libvirt needs a solution now before it can switch to
-blockdev, so let's start with this easier approach for now.
Instead of adding a new auto-read-only option, turning the existing
read-only into an enum (with a bool alternate for compatibility) was
considered, but it complicated the implementation to the point that it
didn't seem to be worth it.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
'detect-zeroes' is one of the basic BlockdevOptions available for all
drivers, but it's not handled by bdrv_reopen_prepare(), so any attempt
to change it results in an error:
(qemu) qemu-io virtio0 "reopen -o detect-zeroes=on"
Cannot change the option 'detect-zeroes'
Since there's no reason why we shouldn't allow changing it and the
implementation is simple let's just do it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
When draining a block node, we recurse to its parent and for subtree
drains also to its children. A single AIO_WAIT_WHILE() is then used to
wait for bdrv_drain_poll() to become true, which depends on all of the
nodes we recursed to. However, if the respective child or parent becomes
quiescent and calls bdrv_wakeup(), only the AioWait of the child/parent
is checked, while AIO_WAIT_WHILE() depends on the AioWait of the
original node.
Fix this by using a single AioWait for all callers of AIO_WAIT_WHILE().
This may mean that the draining thread gets a few more unnecessary
wakeups because an unrelated operation got completed, but we already
wake it up when something _could_ have changed rather than only if it
has certainly changed.
Apart from that, drain is a slow path anyway. In theory it would be
possible to use wakeups more selectively and still correctly, but the
gains are likely not worth the additional complexity. In fact, this
patch is a nice simplification for some places in the code.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
BDRV_REQ_MAY_UNMAP in a write_zeroes request does not only allow the
driver to unmap the blocks, but it actively requests that the blocks be
unmapped afterwards if at all possible.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Other I/O functions are already using a BdrvChild pointer in the API, so
make discard do the same. It makes it possible to initiate the same
permission checks before doing I/O, and much easier to share the
helper functions for this, which will be added and used by write,
truncate and copy range paths.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Serialized writes should be used in copy-on-write of backup(sync=none)
for image fleecing scheme.
We need to change an assert in bdrv_aligned_pwritev, added in
28de2dcd88. The assert may fail now, because call to
wait_serialising_requests here may become first call to it for this
request with serializing flag set. It occurs if the request is aligned
(otherwise, we should already set serializing flag before calling
bdrv_aligned_pwritev and correspondingly waited for all intersecting
requests). However, for aligned requests, we should not care about
outdating of previously read data, as there no such data. Therefore,
let's just update an assert to not care about aligned requests.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Pass read flags and write flags separately. This is needed to handle
coming BDRV_REQ_NO_SERIALISING clearly in following patches.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Here two things are fixed:
1. Architecture
On each recursion step, we go to the child of src or dst, only for one
of them. So, it's wrong to create tracked requests for both on each
step. It leads to tracked requests duplication.
2. Wait for serializing requests on write path independently of
BDRV_REQ_NO_SERIALISING
Before commit 9ded4a0114 "backup: Use copy offloading",
BDRV_REQ_NO_SERIALISING was used for only one case: read in
copy-on-write operation during backup. Also, the flag was handled only
on read path (in bdrv_co_preadv and bdrv_aligned_preadv).
After 9ded4a0114, flag is used for not waiting serializing operations
on backup target (in same case of copy-on-write operation). This
behavior change is unsubstantiated and potentially dangerous, let's
drop it and add additional asserts and documentation.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit dcf94a23b1 ('block: Don't poll in parent drain callbacks')
removed polling in bdrv_child_cb_drained_begin() on the grounds that the
original bdrv_drain() already will poll and BdrvChildRole.drained_begin
calls must not cause graph changes (and therefore must not call
aio_poll() or the recursion through the graph will break.
This reasoning is correct for calls through bdrv_do_drained_begin().
However, BdrvChildRole.drained_begin is also called when a node that is
already in a drained section (i.e. bdrv_do_drained_begin() has already
returned and therefore can't poll any more) is attached to a new parent.
In this case, we must explicitly poll to have all requests completed
before the drained new child can be attached to the parent.
In bdrv_replace_child_noperm(), we know that we're not inside the
recursion of bdrv_do_drained_begin() because graph changes are not
allowed there, and bdrv_replace_child_noperm() is a graph change. The
call of BdrvChildRole.drained_begin() must therefore be followed by a
BDRV_POLL_WHILE() that waits for the completion of requests.
Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This allows using the two constants outside of block.c, which will
happen in a subsequent patch.
Signed-off-by: Ari Sundholm <ari@tuxera.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This semantics is needed by drive-backup so implement it before using
this API there.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 20180703023758.14422-3-famz@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
We are gradually moving away from sector-based interfaces, towards
byte-based. Now that all callers of vectored I/O have been converted
to use our preferred byte-based bdrv_co_p{read,write}v(), we can
delete the unused bdrv_co_{read,write}v().
Furthermore, this gets rid of the signature difference between the
public bdrv_co_writev() and the callback .bdrv_co_writev (the
latter still exists, because some drivers still need more work
before they are fully byte-based).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_truncate() is an operation that can block (even for a quite long
time, depending on the PreallocMode) in I/O paths that shouldn't block.
Convert it to a coroutine_fn so that we have the infrastructure for
drivers to make their .bdrv_co_truncate implementation asynchronous.
This change could potentially introduce new race conditions because
bdrv_truncate() isn't necessarily executed atomically any more. Whether
this is a problem needs to be evaluated for each block driver that
supports truncate:
* file-posix/win32, gluster, iscsi, nfs, rbd, ssh, sheepdog: The
protocol drivers are trivially safe because they don't actually yield
yet, so there is no change in behaviour.
* copy-on-read, crypto, raw-format: Essentially just filter drivers that
pass the request to a child node, no problem.
* qcow2: The implementation modifies metadata, so it needs to hold
s->lock to be safe with concurrent I/O requests. In order to avoid
double locking, this requires pulling the locking out into
preallocate_co() and using qcow2_write_caches() instead of
bdrv_flush().
* qed: Does a single header update, this is fine without locking.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
bdrv_drain_all_*() used bdrv_next() to iterate over all root nodes and
did a subtree drain for each of them. This works fine as long as the
graph is static, but sadly, reality looks different.
If the graph changes so that root nodes are added or removed, we would
have to compensate for this. bdrv_next() returns each root node only
once even if it's the root node for multiple BlockBackends or for a
monitor-owned block driver tree, which would only complicate things.
The much easier and more obviously correct way is to fundamentally
change the way the functions work: Iterate over all BlockDriverStates,
no matter who owns them, and drain them individually. Compensation is
only necessary when a new BDS is created inside a drain_all section.
Removal of a BDS doesn't require any action because it's gone afterwards
anyway.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In the future, bdrv_drained_all_begin/end() will drain all invidiual
nodes separately rather than whole subtrees. This means that we don't
want to propagate the drain to all parents any more: If the parent is a
BDS, it will already be drained separately. Recursing to all parents is
unnecessary work and would make it an O(n²) operation.
Prepare the drain function for the changed drain_all by adding an
ignore_bds_parents parameter to the internal implementation that
prevents the propagation of the drain to BDS parents. We still (have to)
propagate it to non-BDS parents like BlockBackends or Jobs because those
are not drained separately.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_do_drained_begin() is only safe if we have a single
BDRV_POLL_WHILE() after quiescing all affected nodes. We cannot allow
that parent callbacks introduce a nested polling loop that could cause
graph changes while we're traversing the graph.
Split off bdrv_do_drained_begin_quiesce(), which only quiesces a single
node without waiting for its requests to complete. These requests will
be waited for in the BDRV_POLL_WHILE() call down the call chain.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Anything can happen inside BDRV_POLL_WHILE(), including graph
changes that may interfere with its callers (e.g. child list iteration
in recursive callers of bdrv_do_drained_begin).
Switch to a single BDRV_POLL_WHILE() call for the whole subtree at the
end of bdrv_do_drained_begin() to avoid such effects. The recursion
happens now inside the loop condition. As the graph can only change
between bdrv_drain_poll() calls, but not inside of it, doing the
recursion here is safe.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We already requested that block jobs be paused in .bdrv_drained_begin,
but no guarantee was made that the job was actually inactive at the
point where bdrv_drained_begin() returned.
This introduces a new callback BdrvChildRole.bdrv_drained_poll() and
uses it to make bdrv_drain_poll() consider block jobs using the node to
be drained.
For the test case to work as expected, we have to switch from
block_job_sleep_ns() to qemu_co_sleep_ns() so that the test job is even
considered active and must be waited for when draining the node.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is a useful function for the whole block layer, so make it public.
At the same time, users outside of block.c probably do not need to make
use of the reopen functionality, so rename the current function to
bdrv_is_writable_after_reopen() create a new bdrv_is_writable() function
that just passes NULL to it for the reopen queue.
Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180606193702.7113-2-mreitz@redhat.com
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Looking at the qcow2 code that is riddled with error_report() calls,
this is really how it should have been from the start.
Along the way, turn the target_version/current_version comparisons at
the beginning of qcow2_downgrade() into assertions (the caller has to
make sure these conditions are met), and rephrase the error message on
using compat=1.1 to get refcount widths other than 16 bits.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180509210023.20283-3-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Introduce the bdrv_co_copy_range() API for copy offloading. Block
drivers implementing this API support efficient copy operations that
avoid reading each block from the source device and writing it to the
destination devices. Examples of copy offload primitives are SCSI
EXTENDED COPY and Linux copy_file_range(2).
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20180601092648.24614-2-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This flag signifies that a write request will not change the visible
disk content. With this flag set, it is sufficient to have the
BLK_PERM_WRITE_UNCHANGED permission instead of BLK_PERM_WRITE.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20180421132929.21610-4-mreitz@redhat.com
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Currently we never actually check whether the WRITE_UNCHANGED
permission has been taken for unchanging writes. But the one check that
is commented out checks both WRITE and WRITE_UNCHANGED; and considering
that WRITE_UNCHANGED is already documented as being weaker than WRITE,
we should probably explicitly document WRITE to include WRITE_UNCHANGED.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20180421132929.21610-3-mreitz@redhat.com
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
We'll use a separate source file for image creation, and we need to
check there whether the requested driver is whitelisted.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Instead of passing a separate BlockDriverState* into qcow2_co_create(),
make use of the BlockdevRef that is included in BlockdevCreateOptions.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
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Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
Block layer patches
# gpg: Signature made Mon 05 Mar 2018 17:45:51 GMT
# gpg: using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6
* remotes/kevin/tags/for-upstream: (38 commits)
block: Fix NULL dereference on empty drive error
qcow2: Replace align_offset() with ROUND_UP()
block/ssh: Add basic .bdrv_truncate()
block/ssh: Make ssh_grow_file() blocking
block/ssh: Pull ssh_grow_file() from ssh_create()
qemu-img: Make resize error message more general
qcow2: make qcow2_co_create2() a coroutine_fn
block: rename .bdrv_create() to .bdrv_co_create_opts()
Revert "IDE: Do not flush empty CDROM drives"
block: test blk_aio_flush() with blk->root == NULL
block: add BlockBackend->in_flight counter
block: extract AIO_WAIT_WHILE() from BlockDriverState
aio: rename aio_context_in_iothread() to in_aio_context_home_thread()
docs: document how to use the l2-cache-entry-size parameter
specs/qcow2: Fix documentation of the compressed cluster descriptor
iotest 033: add misaligned write-zeroes test via truncate
block: fix write with zero flag set and iovector provided
block: Drop unused .bdrv_co_get_block_status()
vvfat: Switch to .bdrv_co_block_status()
vpc: Switch to .bdrv_co_block_status()
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
# Conflicts:
# include/block/block.h
In my "build everything" tree, a change to the types in
qapi-schema.json triggers a recompile of about 4800 out of 5100
objects.
The previous commit split up qmp-commands.h, qmp-event.h, qmp-visit.h,
qapi-types.h. Each of these headers still includes all its shards.
Reduce compile time by including just the shards we actually need.
To illustrate the benefits: adding a type to qapi/migration.json now
recompiles some 2300 instead of 4800 objects. The next commit will
improve it further.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180211093607.27351-24-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
[eblake: rebase to master]
Signed-off-by: Eric Blake <eblake@redhat.com>
BlockDriverState has the BDRV_POLL_WHILE() macro to wait on event loop
activity while a condition evaluates to true. This is used to implement
synchronous operations where it acts as a condvar between the IOThread
running the operation and the main loop waiting for the operation. It
can also be called from the thread that owns the AioContext and in that
case it's just a nested event loop.
BlockBackend needs this behavior but doesn't always have a
BlockDriverState it can use. This patch extracts BDRV_POLL_WHILE() into
the AioWait abstraction, which can be used with AioContext and isn't
tied to BlockDriverState anymore.
This feature could be built directly into AioContext but then all users
would kick the event loop even if they signal different conditions.
Imagine an AioContext with many BlockDriverStates, each time a request
completes any waiter would wake up and re-check their condition. It's
nicer to keep a separate AioWait object for each condition instead.
Please see "block/aio-wait.h" for details on the API.
The name AIO_WAIT_WHILE() avoids the confusion between AIO_POLL_WHILE()
and AioContext polling.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The name aio_context_in_iothread() is misleading because it also returns
true when called on the main AioContext from the main loop thread, which
is not an IOThread.
This patch renames it to in_aio_context_home_thread() and expands the
doc comment to make the semantics clearer.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We are gradually moving away from sector-based interfaces, towards
byte-based. Now that the block layer exposes byte-based allocation,
it's time to tackle the drivers. Add a new callback that operates
on as small as byte boundaries. Subsequent patches will then update
individual drivers, then finally remove .bdrv_co_get_block_status().
The new code also passes through the 'want_zero' hint, which will
allow subsequent patches to further optimize callers that only care
about how much of the image is allocated (want_zero is false),
rather than full details about runs of zeroes and which offsets the
allocation actually maps to (want_zero is true). As part of this
effort, fix another part of the documentation: the claim in commit
4c41cb4 that BDRV_BLOCK_ALLOCATED is short for 'DATA || ZERO' is a
lie at the block layer (see commit e88ae2264), even though it is
how the bit is computed from the driver layer. After all, there
are intentionally cases where we return ZERO but not ALLOCATED at
the block layer, when we know that a read sees zero because the
backing file is too short. Note that the driver interface is thus
slightly different than the public interface with regards to which
bits will be set, and what guarantees are provided on input.
We also add an assertion that any driver using the new callback will
make progress (the only time pnum will be 0 is if the block layer
already handled an out-of-bounds request, or if there is an error);
the old driver interface did not provide this guarantee, which
could lead to some inf-loops in drastic corner-case failures.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We don't need the can_write_zeroes_with_unmap field in
BlockDriverInfo, because it is redundant information with
supported_zero_flags & BDRV_REQ_MAY_UNMAP. Note that
BlockDriverInfo and supported_zero_flags are both per-device
settings, rather than global state about the driver as a
whole, which means one or both of these bits of information
can already be conditional. Let's audit how they were set:
crypto: always setting can_write_ to false is pointless (the
struct starts life zero-initialized), no use of supported_
nbd: just recently fixed to set can_write_ if supported_
includes MAY_UNMAP (thus this commit effectively reverts
bca80059e and solves the problem mentioned there in a more
global way)
file-posix, iscsi, qcow2: can_write_ is conditional, while
supported_ was unconditional; but passing MAY_UNMAP would
fail with ENOTSUP if the condition wasn't met
qed: can_write_ is unconditional, but pwrite_zeroes lacks
support for MAY_UNMAP and supported_ is not set. Perhaps
support can be added later (since it would be similar to
qcow2), but for now claiming false is no real loss
all other drivers: can_write_ is not set, and supported_ is
either unset or a passthrough
Simplify the code by moving the conditional into
supported_zero_flags for all drivers, then dropping the
now-unused BDI field. For callers that relied on
bdrv_can_write_zeroes_with_unmap(), we return the same
per-device settings for drivers that had conditions (no
observable change in behavior there); and can now return
true (instead of false) for drivers that support passthrough
(for example, the commit driver) which gives those drivers
the same fix as nbd just got in bca80059e. For callers that
relied on supported_zero_flags, we now have a few more places
that can avoid a wasted call to pwrite_zeroes() that will
just fail with ENOTSUP.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180126193439.20219-1-eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
qemu-common.h includes qemu/option.h, but most places that include the
former don't actually need the latter. Drop the include, and add it
to the places that actually need it.
While there, drop superfluous includes of both headers, and
separate #include from file comment with a blank line.
This cleanup makes the number of objects depending on qemu/option.h
drop from 4545 (out of 4743) to 284 in my "build everything" tree.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-20-armbru@redhat.com>
[Semantic conflict with commit bdd6a90a9e in block/nvme.c resolved]
This cleanup makes the number of objects depending on qapi/qmp/qdict.h
drop from 4550 (out of 4743) to 368 in my "build everything" tree.
For qapi/qmp/qobject.h, the number drops from 4552 to 390.
While there, separate #include from file comment with a blank line.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-13-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-11-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-4-armbru@redhat.com>
Allow block driver to map and unmap a buffer for later I/O, as a performance
hint.
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20180116060901.17413-5-famz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
We need to remember how many of the drain sections in which a node is
were recursive (i.e. subtree drain rather than node drain), so that they
can be correctly applied when children are added or removed during the
drained section.
With this change, it is safe to modify the graph even inside a
bdrv_subtree_drained_begin/end() section.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_drained_begin() waits for the completion of requests in the whole
subtree, but it only actually keeps its immediate bs parameter quiesced
until bdrv_drained_end().
Add a version that keeps the whole subtree drained. As of this commit,
graph changes cannot be allowed during a subtree drained section, but
this will be fixed soon.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is in preparation for subtree drains, i.e. drained sections that
affect not only a single node, but recursively all child nodes, too.
Calling the parent callbacks for drain is pointless when we just came
from that parent node recursively and leads to multiple increases of
bs->quiesce_counter in a single drain call. Don't do it.
In order for this to work correctly, the parent callback must be called
for every bdrv_drain_begin/end() call, not only for the outermost one:
If we have a node N with two parents A and B, recursive draining of A
should cause the quiesce_counter of B to increase because its child N is
drained independently of B. If now B is recursively drained, too, A must
increase its quiesce_counter because N is drained independently of A
only now, even if N is going from quiesce_counter 1 to 2.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
On one hand, it is a good idea for bdrv_next() to return a strong
reference because ideally nearly every pointer should be refcounted.
This fixes intermittent failure of iotest 194.
On the other, it is absolutely necessary for bdrv_next() itself to keep
a strong reference to both the BB (in its first phase) and the BDS (at
least in the second phase) because when called the next time, it will
dereference those objects to get a link to the next one. Therefore, it
needs these objects to stay around until then. Just storing the pointer
to the next in the iterator is not really viable because that pointer
might become invalid as well.
Both arguments taken together means we should probably just invoke
bdrv_ref() and blk_ref() in bdrv_next(). This means we have to assert
that bdrv_next() is always called from the main loop, but that was
probably necessary already before this patch and judging from the
callers, it also looks to actually be the case.
Keeping these strong references means however that callers need to give
them up if they decide to abort the iteration early. They can do so
through the new bdrv_next_cleanup() function.
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171110172545.32609-1-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
We are gradually moving away from sector-based interfaces, towards
byte-based. In the common case, allocation is unlikely to ever use
values that are not naturally sector-aligned, but it is possible
that byte-based values will let us be more precise about allocation
at the end of an unaligned file that can do byte-based access.
Changing the name of the function from bdrv_get_block_status_above()
to bdrv_block_status_above() ensures that the compiler enforces that
all callers are updated. Likewise, since it a byte interface allows
an offset mapping that might not be sector aligned, split the mapping
out of the return value and into a pass-by-reference parameter. For
now, the io.c layer still assert()s that all uses are sector-aligned,
but that can be relaxed when a later patch implements byte-based
block status in the drivers.
For the most part this patch is just the addition of scaling at the
callers followed by inverse scaling at bdrv_block_status(), plus
updates for the new split return interface. But some code,
particularly bdrv_block_status(), gets a lot simpler because it no
longer has to mess with sectors. Likewise, mirror code no longer
computes s->granularity >> BDRV_SECTOR_BITS, and can therefore drop
an assertion about alignment because the loop no longer depends on
alignment (never mind that we don't really have a driver that
reports sub-sector alignments, so it's not really possible to test
the effect of sub-sector mirroring). Fix a neighboring assertion to
use is_power_of_2 while there.
For ease of review, bdrv_get_block_status() was tackled separately.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We are gradually moving away from sector-based interfaces, towards
byte-based. In the common case, allocation is unlikely to ever use
values that are not naturally sector-aligned, but it is possible
that byte-based values will let us be more precise about allocation
at the end of an unaligned file that can do byte-based access.
Changing the name of the function from bdrv_get_block_status() to
bdrv_block_status() ensures that the compiler enforces that all
callers are updated. For now, the io.c layer still assert()s that
all callers are sector-aligned, but that can be relaxed when a later
patch implements byte-based block status in the drivers.
There was an inherent limitation in returning the offset via the
return value: we only have room for BDRV_BLOCK_OFFSET_MASK bits, which
means an offset can only be mapped for sector-aligned queries (or,
if we declare that non-aligned input is at the same relative position
modulo 512 of the answer), so the new interface also changes things to
return the offset via output through a parameter by reference rather
than mashed into the return value. We'll have some glue code that
munges between the two styles until we finish converting all uses.
For the most part this patch is just the addition of scaling at the
callers followed by inverse scaling at bdrv_block_status(), coupled
with the tweak in calling convention. But some code, particularly
bdrv_is_allocated(), gets a lot simpler because it no longer has to
mess with sectors.
For ease of review, bdrv_get_block_status_above() will be tackled
separately.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In the process of converting sector-based interfaces to bytes,
I'm finding it easier to represent a byte count as a 64-bit
integer at the block layer (even if we are internally capped
by SIZE_MAX or even INT_MAX for individual transactions, it's
still nicer to not have to worry about truncation/overflow
issues on as many variables). Update the signature of
bdrv_round_to_clusters() to uniformly use int64_t, matching
the signature already chosen for bdrv_is_allocated and the
fact that off_t is also a signed type, then adjust clients
according to the required fallout (even where the result could
now exceed 32 bits, no client is directly assigning the result
into a 32-bit value without breaking things into a loop first).
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We don't need to make any assumptions about the graph layout above the
top node of the commit operation any more. Remove the use of
bdrv_find_overlay() and related variables from the commit job code.
bdrv_drop_intermediate() doesn't use the 'active' parameter any more, so
we can just drop it.
The overlay node was previously added to the block job to get a
BLK_PERM_GRAPH_MOD. We really need to respect those permissions in
bdrv_drop_intermediate() now, but as long as we haven't figured out yet
how BLK_PERM_GRAPH_MOD is actually supposed to work, just leave a TODO
comment there.
With this change, it is now possible to perform another block job on an
overlay node without conflicts. qemu-iotests 030 is changed accordingly.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
If we switch between read-only and read-write, the permissions that
image format drivers need on bs->file change, too. Make sure to update
the permissions during bdrv_reopen().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
When new permissions are calculated during bdrv_reopen(), they need to
be based on the state of the graph as it will be after the reopen has
completed, not on the current state of the involved nodes.
This patch makes bdrv_is_writable() optionally accept a BlockReopenQueue
from which the new flags are taken. This is then used for determining
the new bs->file permissions of format drivers as soon as we add the
code to actually pass a non-NULL reopen queue to the .bdrv_child_perm
callbacks.
While moving bdrv_is_writable(), make it static. It isn't used outside
block.c.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
This function is not used anywhere, so remove it.
Markus Armbruster adds:
The i82078 floppy device model used to call bdrv_media_changed() to
implement its media change bit when backed by a host floppy. This
went away in 21fcf36 "fdc: simplify media change handling".
Probably broke host floppy media change. Host floppy pass-through
was dropped in commit f709623. bdrv_media_changed() has never been
used for anything else. Remove it.
(Source is Message-ID: <87y3ruaypm.fsf@dusky.pond.sub.org>)
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
BDRV_O_ALLOW_RDWR is a flag that tells whether qemu can internally
reopen a node read-write temporarily because the user requested
read-write for the top-level image, but qemu decided that read-only is
enough for this node (a backing file).
bdrv_reopen() is different, it is also used for cases where the user
changed their mind and wants to update the options. There is no reason
to forbid making a node read-write in that case.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Commits 0db832f and 6cdbceb introduced the automatic insertion of filter
nodes above the top layer of mirror and commit block jobs. The
assumption made there was that since libvirt doesn't do node-level
management of the block layer yet, it shouldn't be affected by added
nodes.
This is true as far as commands issued by libvirt are concerned. It only
uses BlockBackend names to address nodes, so any operations it performs
still operate on the root of the tree as intended.
However, the assumption breaks down when you consider query commands,
which return data for the wrong node now. These commands also return
information on some child nodes (bs->file and/or bs->backing), which
libvirt does make use of, and which refer to the wrong nodes, too.
One of the consequences is that oVirt gets wrong information about the
image size and stops the VM in response as long as a mirror or commit
job is running:
https://bugzilla.redhat.com/show_bug.cgi?id=1470634
This patch fixes the problem by hiding the implicit nodes created
automatically by the mirror and commit block jobs in the output of
query-block and BlockBackend-based query-blockstats as long as the user
doesn't indicate that they are aware of those nodes by providing a node
name for them in the QMP command to start the block job.
The node-based commands query-named-block-nodes and query-blockstats
with query-nodes=true still show all nodes, including implicit ones.
This ensures that users that are capable of node-level management can
still access the full information; users that only know BlockBackends
won't use these commands.
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
