Add some debugging to flag servers that are not compliant to
the NBD protocol. This would have flagged the server bug
fixed in commit c0301fcc.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alex Bligh <alex@alex.org.uk>
Message-Id: <1463006384-7734-11-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The kernel ioctl() interface into NBD is limited to 'unsigned long';
we MUST pass in input with that type (and not int or size_t, as
there may be platform ABIs where the wrong types promote incorrectly
through var-args). Furthermore, on 32-bit platforms, the kernel
is limited to a maximum export size of 2T (our BLKSIZE of 512 times
a SIZE_BLOCKS constrained by 32 bit unsigned long).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-8-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
NBD ioctl()s are used to manage an NBD client session where
initial handshake is done in userspace, but then the transmission
phase is handed off to the kernel through a /dev/nbdX device.
As such, all ioctls sent to the kernel on the /dev/nbdX fd belong
in client.c; nbd_disconnect() was out-of-place in server.c.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-7-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The NBD protocol says that clients should not send a command flag
that has not been negotiated (whether by the client requesting an
option during a handshake, or because we advertise support for the
flag in response to NBD_OPT_EXPORT_NAME), and that servers should
reject invalid flags with EINVAL. We were silently ignoring the
flags instead. The client can't rely on our behavior, since it is
their fault for passing the bad flag in the first place, but it's
better to be robust up front than to possibly behave differently
than the client was expecting with the attempted flag.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alex Bligh <alex@alex.org.uk>
Message-Id: <1463006384-7734-6-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We have a few bugs in how we handle invalid client commands:
- A client can send an NBD_CMD_DISC where from + len overflows,
convincing us to reply with an error and stay connected, even
though the protocol requires us to silently disconnect. Fix by
hoisting the special case sooner.
- A client can send an NBD_CMD_WRITE where from + len overflows,
where we reply to the client with EINVAL without consuming the
payload; this will normally cause us to fail if the next thing
read is not the right magic, but in rare cases, could cause us
to interpret the data payload as valid commands and do things
not requested by the client. Fix by adding a complete flag to
track whether we are in sync or must disconnect.
Furthermore, we have split the checks for bogus from/len across
two functions, when it is easier to do it all at once.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-5-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We should never ignore failure from nbd_negotiate_send_rep(); if
we are unable to write to the client, then it is not worth trying
to continue the negotiation. Fortunately, the problem is not
too severe - chances are that the errors being ignored here (mainly
inability to write the reply to the client) are indications of
a closed connection or something similar, which will also affect
the next attempt to interact with the client and eventually reach
a point where the errors are detected to end the loop.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-4-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Clean up some debug message oddities missed earlier; this includes
some typos, and recognizing that %d is not necessarily compatible
with uint32_t. Also add a couple messages that I found useful
while debugging things.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-3-git-send-email-eblake@redhat.com>
[Do not use PRIx16, clang complains. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Rather than always flushing ourselves, let the block layer
forward the FUA on to the underlying device - where all
underlying layers also understand FUA, we are now more
efficient; and where any underlying layer doesn't understand
it, now the block layer takes care of the full flush fallback
on our behalf.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-2-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
QEMU compiles a list of data directories from various sources. When
consuming a QEMU binary it's useful to be able to get this list of
data directories: a primary reason is so you can list what BIOSes or
keymaps ship with this version of QEMU. However without reproducing
the method that QEMU uses internally, it's not possible to get the
list of data directories.
This commit adds a simple '-L help' option that just lists out the
data directories as qemu calculates them:
$ ./x86_64-softmmu/qemu-system-x86_64 -L help
/home/rjones/d/qemu/pc-bios
/usr/local/share/qemu
$ ./x86_64-softmmu/qemu-system-x86_64 -L /tmp -L help
/tmp
/home/rjones/d/qemu/pc-bios
/usr/local/share/qemu
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463416475-11728-2-git-send-email-rjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As stated in linux/Documentation/virtual/kvm/api.txt:
The maximum possible value for max_vcpu_id can be retrieved using the
KVM_CAP_MAX_VCPU_ID of the KVM_CHECK_EXTENSION ioctl() at run-time.
If the KVM_CAP_MAX_VCPU_ID does not exist, you should assume that
max_vcpu_id is the same as the value returned from KVM_CAP_MAX_VCPUS.
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Message-Id: <146424974323.5666.5471538288045048119.stgit@bahia.huguette.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some source code analyzers like cppcheck spill out a warning if
the sign of the argument does not match the format string.
Ticket: https://bugs.launchpad.net/qemu/+bug/1589564
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1465805418-15906-1-git-send-email-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM_GET_SUPPORTED_CPUID ioctl is called frequently when initializing
CPU. Depends on CPU features and CPU count, the number of calls can be
extremely high which slows down QEMU booting significantly. In our
testing, we saw 5922 calls with switches:
-cpu SandyBridge -smp 6,sockets=6,cores=1,threads=1
This ioctl takes more than 100ms, which is almost half of the total
QEMU startup time.
While for most cases the data returned from two different invocations
are not changed, that means, we can cache the data to avoid trapping
into kernel for the second time. To make sure the cache safe one
assumption is desirable: the ioctl is stateless. This is not true for
CPUID leaves in general (such as CPUID leaf 0xD, whose value depends
on guest XCR0 and IA32_XSS) but it is true of KVM_GET_SUPPORTED_CPUID,
which runs before there is a value for XCR0 and IA32_XSS.
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Message-Id: <1465784487-23482-1-git-send-email-chao.p.peng@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
These structs are never used to represent the bytes that go over the
network. The big-endian network data is built into a uint8_t array
in nbd_{receive,send}_{request,reply}. Remove the unused magic field,
reorder the struct to avoid holes, and remove the packed attribute.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The cpu_to_*w() functions just compose a pointer dereference
with a byteswap. Instead use st*_p(), which handles potential
pointer misalignment and avoids the need to cast the pointer.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <1465575342-12146-1-git-send-email-peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The *_to_cpup() functions are not very useful, as they simply do
a pointer dereference and then a *_to_cpu(). Instead use either:
* ld*_*_p(), if the data is at an address that might not be
correctly aligned for the load
* a local dereference and *_to_cpu(), if the pointer is
the correct type and known to be correctly aligned
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <1465570836-22211-1-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The CONFIG_SIGEV_THREAD_ID switch is unused since the related code
has been removed by commit 6d32717155
("aio / timers: Remove alarm timers"), so it can safely be removed
nowadays.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1465571084-19885-1-git-send-email-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Use the avx2 primitives during the test, thus making sure that the
compiler and assembler could actually use avx2.
This also detects the failure case on gcc 4.8.x with -save-temps
and avoids the need for the gcc version check in cutils.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1465557378-24105-3-git-send-email-dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When configured with --extra-cflags=-O2 gcc optimised out the test
and the readelf failed the check leaving avx2 disabled.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1465557378-24105-2-git-send-email-dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
"ctags" produces a file named "tags", not "ctags". It doesn't look
reasonable to use phony target name as a file name to remove. Just use
exact file names to remove in "ctags" and "TAGS" target receipts.
Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Message-Id: <1465495115-24665-1-git-send-email-sergey.fedorov@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
MinGW seems to compile currently without warnings, so it should
be safe to enable -Werror now for this environment, too.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1465373606-18486-1-git-send-email-thuth@redhat.com>
Tested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qemu/osdep.h checks whether MAP_ANONYMOUS is defined, but this check
is bogus without a previous inclusion of sys/mman.h. Include it in
sysemu/os-posix.h and remove it from everywhere else.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
CONFIG_ZERO_MALLOC was only used in qemu-malloc.c and
this file has been removed with the following commit:
41a748265f
Remove qemu_malloc/qemu_free
So we don't need this configuration setting anymore.
This patch also removes the z_version variable, since
this is now also not needed anymore.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <1465398683-3152-1-git-send-email-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
Block layer patches
# gpg: Signature made Thu 16 Jun 2016 15:01:27 BST
# gpg: using RSA key 0x7F09B272C88F2FD6
# 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: (39 commits)
hbitmap: add 'pos < size' asserts
iotests: Add test for oVirt-like storage migration
iotests: Add test for post-mirror backing chains
block/null: Implement bdrv_refresh_filename()
block/mirror: Fix target backing BDS
block: Allow replacement of a BDS by its overlay
rbd:change error_setg() to error_setg_errno()
iotests: 095: Clean up QEMU before showing image info
block: Create the commit block job before reopening any image
block: Prevent sleeping jobs from resuming if they have been paused
block: use the block job list in qmp_query_block_jobs()
block: use the block job list in bdrv_drain_all()
block: Fix snapshot=on with aio=native
block: Remove bs->zero_beyond_eof
qcow2: Let vmstate call qcow2_co_preadv/pwrite directly
block: Make bdrv_load/save_vmstate coroutine_fns
block: Allow .bdrv_load/save_vmstate() to return 0/-errno
block: Make .bdrv_load_vmstate() vectored
block: Introduce bdrv_preadv()
doc: Fix mailing list address in tests/qemu-iotests/README
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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Merge remote-tracking branch 'mreitz/tags/pull-block-for-kevin-2016-06-16' into queue-block
Block patches
# gpg: Signature made Thu Jun 16 15:21:35 2016 CEST
# gpg: using RSA key 0x3BB14202E838ACAD
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>"
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1 1829 F407 DB00 61D5 CF40
# Subkey fingerprint: 58B3 81CE 2DC8 9CF9 9730 EE64 3BB1 4202 E838 ACAD
* mreitz/tags/pull-block-for-kevin-2016-06-16:
hbitmap: add 'pos < size' asserts
iotests: Add test for oVirt-like storage migration
iotests: Add test for post-mirror backing chains
block/null: Implement bdrv_refresh_filename()
block/mirror: Fix target backing BDS
block: Allow replacement of a BDS by its overlay
rbd:change error_setg() to error_setg_errno()
iotests: 095: Clean up QEMU before showing image info
block: Create the commit block job before reopening any image
block: Prevent sleeping jobs from resuming if they have been paused
block: use the block job list in qmp_query_block_jobs()
block: use the block job list in bdrv_drain_all()
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
For now, fail in hbitmap_set on start + count > size will come from
hbitmap_set
hb_count_between
hbitmap_iter_init
assert(pos < hb->size)
This patch adds such checks to set/get/reset functions of hbitmap.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 1465924093-76875-2-git-send-email-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20160610185750.30956-6-mreitz@redhat.com
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
The null block driver ignores any filename used for creating its BDSs,
which allows creating such BDSs even without any filename at all. In
that case, we currently construct a JSON filename when queried instead
of a plain "null-co://" or "null-aio://". This patch implements
bdrv_refresh_filename() to remedy this behavior.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20160610185750.30956-4-mreitz@redhat.com
[mreitz@redhat.com: Added commit message]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Currently, we are trying to move the backing BDS from the source to the
target in bdrv_replace_in_backing_chain() which is called from
mirror_exit(). However, mirror_complete() already tries to open the
target's backing chain with a call to bdrv_open_backing_file().
First, we should only set the target's backing BDS once. Second, the
mirroring block job has a better idea of what to set it to than the
generic code in bdrv_replace_in_backing_chain() (in fact, the latter's
conditions on when to move the backing BDS from source to target are not
really correct).
Therefore, remove that code from bdrv_replace_in_backing_chain() and
leave it to mirror_complete().
Depending on what kind of mirroring is performed, we furthermore want to
use different strategies to open the target's backing chain:
- If blockdev-mirror is used, we can assume the user made sure that the
target already has the correct backing chain. In particular, we should
not try to open a backing file if the target does not have any yet.
- If drive-mirror with mode=absolute-paths is used, we can and should
reuse the already existing chain of nodes that the source BDS is in.
In case of sync=full, no backing BDS is required; with sync=top, we
just link the source's backing BDS to the target, and with sync=none,
we use the source BDS as the target's backing BDS.
We should not try to open these backing files anew because this would
lead to two BDSs existing per physical file in the backing chain, and
we would like to avoid such concurrent access.
- If drive-mirror with mode=existing is used, we have to use the
information provided in the physical image file which means opening
the target's backing chain completely anew, just as it has been done
already.
If the target's backing chain shares images with the source, this may
lead to multiple BDSs per physical image file. But since we cannot
reliably ascertain this case, there is nothing we can do about it.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20160610185750.30956-3-mreitz@redhat.com
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
change_parent_backing_link() asserts that the BDS to be replaced is not
used as a backing file. However, we may want to replace a BDS by its
overlay in which case that very link should not be redirected.
For instance, when doing a sync=none drive-mirror operation, we may have
the following BDS/BB forest before block job completion:
target
base <- source <- BlockBackend
During job completion, we want to establish the source BDS as the
target's backing node:
target
|
v
base <- source <- BlockBackend
This makes the target a valid replacement for the source:
target <- BlockBackend
|
v
base <- source
Without this modification to change_parent_backing_link() we have to
inject the target into the graph before the source is its backing node,
thus temporarily creating a wrong graph:
target <- BlockBackend
base <- source
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20160610185750.30956-2-mreitz@redhat.com
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Ceph RBD block driver does not use error_setg_errno() where
it is possible to use. This patch replaces error_setg()
from error_setg_errno().
Signed-off-by: Vikhyat Umrao <vumrao@redhat.com>
Message-id: 1462780319-5796-1-git-send-email-vumrao@redhat.com
Reviewed-by: Josh Durgin <jdurgin@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
If the base or overlay images need to be reopened in read-write mode
but the block_job_create() call fails then no one will put those
images back in read-only mode.
We can solve this problem easily by calling block_job_create() first.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: aa495045770a6f1a7cc5d408397a17c75097fdd8.1464346103.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
If we pause a block job and drain its BlockDriverState we want that
the job remains inactive until we call block_job_resume() again.
However if we pause the job while it is sleeping then it will resume
when the sleep timer fires.
This patch prevents that from happening by checking if the job has
been paused after it comes back from sleeping.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 3d9011151512326b890d22bdab3530244ef349d7.1464346103.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
qmp_query_block_jobs() uses bdrv_next() to look for block jobs, but
this function can only find those in top-level BlockDriverStates.
This patch uses block_job_next() instead.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: a8b7e5497b7c1fa67c12fcceae1630d01c3b1f96.1464346103.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
bdrv_drain_all() pauses all block jobs by using bdrv_next() to iterate
over all top-level BlockDriverStates. Therefore the code is unable to
find block jobs in other nodes.
This patch uses block_job_next() to iterate over all block jobs.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 55ee7d7d4a65c28aa1a1b28823897ef326f328e2.1464346103.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
snapshot=on creates a temporary overlay that is always opened with
cache=unsafe (the cache mode specified by the user is only for the
actual image file and its children). This means that we must not inherit
the BDRV_O_NATIVE_AIO flag for the temporary overlay because trying to
use Linux AIO with cache=unsafe results in an error.
Reproducer without this patch:
$ x86_64-softmmu/qemu-system-x86_64 -drive file=/tmp/test.qcow2,cache=none,aio=native,snapshot=on
qemu-system-x86_64: -drive file=/tmp/test.qcow2,cache=none,aio=native,snapshot=on: aio=native was
specified, but it requires cache.direct=on, which was not specified.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
It is always true for open images now.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
We don't really want to go through the block layer in order to read from
or write to the vmstate in a qcow2 image. Doing so required a few ugly
hacks like saving and restoring the old image size (because writing to
vmstate offsets would increase the image size) or disabling the "reads
after EOF = zeroes" logic. When calling the right functions directly,
these hacks aren't necessary any more.
Note that .bdrv_vmstate_load/save() return 0 instead of the number of
bytes in case of success now.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
This allows drivers to share code between normal I/O and vmstate
accesses.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The return value of .bdrv_load/save_vmstate() can be any non-negative
number in case of success now. It used to be bytes/-errno.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
This brings it in line with .bdrv_save_vmstate().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
We already have a byte-based bdrv_pwritev(), but the read counterpart
was still missing. This commit adds it.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The address of the mailing list is qemu-devel@nongnu.org
instead of qemu-devel@savannah.nongnu.org. And while we're
at it, also mention the qemu-block mailing list here.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
linux-aio uses a BH in order to make sure that the remaining completions
are processed even in nested event loops of completion callbacks in
order to avoid deadlocks.
There is no need, however, to have the BH overhead for the first call
into qemu_laio_completion_bh() or after all pending completions have
already been processed. Therefore, this patch calls directly into
qemu_laio_completion_bh() in qemu_laio_completion_cb() and cancels
the BH after qemu_laio_completion_bh() has processed all pending
completions.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
If block drivers say that they can do an alignment < 512 bytes, let's
just suppose they mean it. raw-posix used to be an offender with respect
to this, but it can actually deal with byte-aligned requests now.
The default is still 512 bytes for any drivers that only implement
sector-based interfaces, but it is 1 now for drivers that implement
.bdrv_co_preadv.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The raw-posix block driver actually supports byte-aligned requests now
on non-O_DIRECT images, like it already (and previously incorrectly)
claimed in bs->request_alignment.
For some block drivers this means that a RMW cycle can be avoided when
they write sub-sector metadata e.g. for cluster allocation.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
In order to use the modern byte-based .bdrv_co_preadv/pwritev()
interface, this patch switches raw-posix to coroutine-based interfaces
as a first step. In terms of semantics and performance, it doesn't make
a difference with the existing code whether we go from a coroutine to a
callback-based interface already in block/io.c or only in linux-aio.c
As there have been concerns in the past that this change may be a step
in the wrong direction with respect to a possible AIO fast path, the
old callback-based interface for linux-aio is left around and can be
reactivated when a fast path (e.g. directly from virtio-blk dataplane,
bypassing the whole block layer) is implemented.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Eric Blake
Richard W.M. Jones
Greg Kurz
Thomas Huth
Chao Peng
Paolo Bonzini
Peter Maydell
Dr. David Alan Gilbert
Sergey Fedorov
Kevin Wolf
Vladimir Sementsov-Ogievskiy
Max Reitz
Vikhyat Umrao
Fam Zheng
Alberto Garcia