nbd_co_establish_connection_cancel() actually needs only pointer to
NBDConnectThread. So, make it clean.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-14-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
We are going to split connection code to a separate file. Now we are
ready to give nbd_co_establish_connection() clean and bs-independent
interface.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-13-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
We don't need all these states. The code refactored to use two boolean
variables looks simpler.
While moving the comment in nbd_co_establish_connection() rework it to
give better information. Also, we are going to move the connection code
to separate file and mentioning drained section would be confusing.
Improve also the comment in NBDConnectThread, while dropping removed
state names from it.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-12-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: comment tweak]
Signed-off-by: Eric Blake <eblake@redhat.com>
Instead of managing connect_bh, bh_ctx, and wait_connect fields, we
can use a single link to the waiting coroutine with proper mutex
protection.
So new logic is:
nbd_co_establish_connection() sets wait_co under the mutex, releases
the mutex, then yield()s. Note that wait_co may be scheduled by the
thread immediately after unlocking the mutex. Still, the main thread
(or iothread) will not reach the code for entering the coroutine until
the yield(), so we are safe.
connect_thread_func() and nbd_co_establish_connection_cancel() do
the following to handle wait_co:
Under the mutex, if thr->wait_co is not NULL, make it NULL and
schedule it. This way, we avoid scheduling the coroutine twice.
Still scheduling is a bit different:
In connect_thread_func() we can just call aio_co_wake under mutex,
after commit
[async: the main AioContext is only "current" if under the BQL]
we are sure that aio_co_wake() will not try to acquire the aio context
and do qemu_aio_coroutine_enter() but simply schedule the coroutine by
aio_co_schedule().
nbd_co_establish_connection_cancel() will be called from non-coroutine
context in further patch and will be able to go through
qemu_aio_coroutine_enter() path of aio_co_wake(). So keep current
behavior of waking the coroutine after the critical section.
Also, this commit reduces the dependence of
nbd_co_establish_connection() on the internals of bs (we now use a
generic pointer to the coroutine, instead of direct use of
s->connection_co). This is a step towards splitting the connection
API out of nbd.c.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-11-vsementsov@virtuozzo.com>
Reviewied-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
These fields are write-only. Drop them.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-10-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Message-Id: <20210610100802.5888-9-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Simplify lifetime management of BDRVNBDState->connect_thread by
delaying the possible cleanup of it until the BDRVNBDState itself goes
away.
This also reverts
0267101af6 "block/nbd: fix possible use after free of s->connect_thread"
as now s->connect_thread can't be cleared until the very end.
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
[vsementsov: rebase, revert 0267101af6 changes]
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[eblake: tweak comment]
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-8-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Detecting monitor by current coroutine works bad when we are not in
coroutine context. And that's exactly so in nbd reconnect code, where
qio_channel_socket_connect_sync() is called from thread.
Monitor is needed only to parse named file descriptor. So, let's just
parse it during nbd_open(), so that all further users of s->saddr don't
need to access monitor.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-7-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
nbd_open() does it (through nbd_establish_connection()).
Actually we lost that call on reconnect path in 1dc4718d84
"block/nbd: use non-blocking connect: fix vm hang on connect()"
when we have introduced reconnect thread.
Fixes: 1dc4718d84
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-5-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
We have two "return error" paths in nbd_open() after
nbd_process_options(). Actually we should call nbd_clear_bdrvstate()
on these paths. Interesting that nbd_process_options() calls
nbd_clear_bdrvstate() by itself.
Let's fix leaks and refactor things to be more obvious:
- intialize yank at top of nbd_open()
- move yank cleanup to nbd_clear_bdrvstate()
- refactor nbd_open() so that all failure paths except for
yank-register goes through nbd_clear_bdrvstate()
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-4-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
nbd_free_connect_thread leaks the channel object if it hasn't been
stolen.
Unref it and fix the leak.
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-3-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Right now, users of qemu_co_sleep_ns_wakeable are simply passing
a pointer to QemuCoSleepState by reference to the function. But
QemuCoSleepState really is just a Coroutine*; making the
content of the struct public is just as efficient and lets us
skip the user_state_pointer indirection.
Since the usage is changed, take the occasion to rename the
struct to QemuCoSleep.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20210517100548.28806-6-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
All callers of qemu_co_sleep_wake are checking whether they are passing
a NULL argument inside the pointer-to-pointer: do the check in
qemu_co_sleep_wake itself.
As a side effect, qemu_co_sleep_wake can be called more than once and
it will only wake the coroutine once; after the first time, the argument
will be set to NULL via *sleep_state->user_state_pointer. However, this
would not be safe unless co_sleep_cb keeps using the QemuCoSleepState*
directly, so make it go through the pointer-to-pointer instead.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20210517100548.28806-4-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
If on nbd_close() we detach the thread (in
nbd_co_establish_connection_cancel() thr->state becomes
CONNECT_THREAD_RUNNING_DETACHED), after that point we should not use
s->connect_thread (which is set to NULL), as running thread may free it
at any time.
Still nbd_co_establish_connection() does exactly this: it saves
s->connect_thread to local variable (just for better code style) and
use it even after yield point, when thread may be already detached.
Fix that. Also check thr to be non-NULL on
nbd_co_establish_connection() start for safety.
After this patch "case CONNECT_THREAD_RUNNING_DETACHED" becomes
impossible in the second switch in nbd_co_establish_connection().
Still, don't add extra abort() just before the release. If it somehow
possible to reach this "case:" it won't hurt. Anyway, good refactoring
of all this reconnect mess will come soon.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210406155114.1057355-1-vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Just stop waiting for connection in existing requests.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210205163720.887197-3-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
When an NBD block driver state is moved from one aio_context to another
(e.g. when doing a drain in a migration thread),
nbd_client_attach_aio_context_bh is executed that enters the connection
coroutine.
However, the assumption that ->connection_co is always present here
appears incorrect: the connection may have encountered an error other
than -EIO in the underlying transport, and thus may have decided to quit
rather than keep trying to reconnect, and therefore it may have
terminated the connection coroutine. As a result an attempt to reassign
the client in this state (NBD_CLIENT_QUIT) to a different aio_context
leads to a null pointer dereference:
#0 qio_channel_detach_aio_context (ioc=0x0)
at /build/qemu-gYtjVn/qemu-5.0.1/io/channel.c:452
#1 0x0000562a242824b3 in bdrv_detach_aio_context (bs=0x562a268d6a00)
at /build/qemu-gYtjVn/qemu-5.0.1/block.c:6151
#2 bdrv_set_aio_context_ignore (bs=bs@entry=0x562a268d6a00,
new_context=new_context@entry=0x562a260c9580,
ignore=ignore@entry=0x7feeadc9b780)
at /build/qemu-gYtjVn/qemu-5.0.1/block.c:6230
#3 0x0000562a24282969 in bdrv_child_try_set_aio_context
(bs=bs@entry=0x562a268d6a00, ctx=0x562a260c9580,
ignore_child=<optimized out>, errp=<optimized out>)
at /build/qemu-gYtjVn/qemu-5.0.1/block.c:6332
#4 0x0000562a242bb7db in blk_do_set_aio_context (blk=0x562a2735d0d0,
new_context=0x562a260c9580,
update_root_node=update_root_node@entry=true, errp=errp@entry=0x0)
at /build/qemu-gYtjVn/qemu-5.0.1/block/block-backend.c:1989
#5 0x0000562a242be0bd in blk_set_aio_context (blk=<optimized out>,
new_context=<optimized out>, errp=errp@entry=0x0)
at /build/qemu-gYtjVn/qemu-5.0.1/block/block-backend.c:2010
#6 0x0000562a23fbd953 in virtio_blk_data_plane_stop (vdev=<optimized
out>)
at /build/qemu-gYtjVn/qemu-5.0.1/hw/block/dataplane/virtio-blk.c:292
#7 0x0000562a241fc7bf in virtio_bus_stop_ioeventfd (bus=0x562a260dbf08)
at /build/qemu-gYtjVn/qemu-5.0.1/hw/virtio/virtio-bus.c:245
#8 0x0000562a23fefb2e in virtio_vmstate_change (opaque=0x562a260dbf90,
running=0, state=<optimized out>)
at /build/qemu-gYtjVn/qemu-5.0.1/hw/virtio/virtio.c:3220
#9 0x0000562a2402ebfd in vm_state_notify (running=running@entry=0,
state=state@entry=RUN_STATE_FINISH_MIGRATE)
at /build/qemu-gYtjVn/qemu-5.0.1/softmmu/vl.c:1275
#10 0x0000562a23f7bc02 in do_vm_stop (state=RUN_STATE_FINISH_MIGRATE,
send_stop=<optimized out>)
at /build/qemu-gYtjVn/qemu-5.0.1/cpus.c:1032
#11 0x0000562a24209765 in migration_completion (s=0x562a260e83a0)
at /build/qemu-gYtjVn/qemu-5.0.1/migration/migration.c:2914
#12 migration_iteration_run (s=0x562a260e83a0)
at /build/qemu-gYtjVn/qemu-5.0.1/migration/migration.c:3275
#13 migration_thread (opaque=opaque@entry=0x562a260e83a0)
at /build/qemu-gYtjVn/qemu-5.0.1/migration/migration.c:3439
#14 0x0000562a2435ca96 in qemu_thread_start (args=<optimized out>)
at /build/qemu-gYtjVn/qemu-5.0.1/util/qemu-thread-posix.c:519
#15 0x00007feed31466ba in start_thread (arg=0x7feeadc9c700)
at pthread_create.c:333
#16 0x00007feed2e7c41d in __GI___sysctl (name=0x0, nlen=608471908,
oldval=0x562a2452b138, oldlenp=0x0, newval=0x562a2452c5e0
<__func__.28102>, newlen=0)
at ../sysdeps/unix/sysv/linux/sysctl.c:30
#17 0x0000000000000000 in ?? ()
Fix it by checking that the connection coroutine is non-null before
trying to enter it. If it is null, no entering is needed, as the
connection is probably going down anyway.
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210129073859.683063-3-rvkagan@yandex-team.ru>
Signed-off-by: Eric Blake <eblake@redhat.com>
When the reconnect in NBD client is in progress, the iochannel used for
NBD connection doesn't exist. Therefore an attempt to detach it from
the aio_context of the parent BlockDriverState results in a NULL pointer
dereference.
The problem is triggerable, in particular, when an outgoing migration is
about to finish, and stopping the dataplane tries to move the
BlockDriverState from the iothread aio_context to the main loop. If the
NBD connection is lost before this point, and the NBD client has entered
the reconnect procedure, QEMU crashes:
#0 qemu_aio_coroutine_enter (ctx=0x5618056c7580, co=0x0)
at /build/qemu-6MF7tq/qemu-5.0.1/util/qemu-coroutine.c:109
#1 0x00005618034b1b68 in nbd_client_attach_aio_context_bh (
opaque=0x561805ed4c00) at /build/qemu-6MF7tq/qemu-5.0.1/block/nbd.c:164
#2 0x000056180353116b in aio_wait_bh (opaque=0x7f60e1e63700)
at /build/qemu-6MF7tq/qemu-5.0.1/util/aio-wait.c:55
#3 0x0000561803530633 in aio_bh_call (bh=0x7f60d40a7e80)
at /build/qemu-6MF7tq/qemu-5.0.1/util/async.c:136
#4 aio_bh_poll (ctx=ctx@entry=0x5618056c7580)
at /build/qemu-6MF7tq/qemu-5.0.1/util/async.c:164
#5 0x0000561803533e5a in aio_poll (ctx=ctx@entry=0x5618056c7580,
blocking=blocking@entry=true)
at /build/qemu-6MF7tq/qemu-5.0.1/util/aio-posix.c:650
#6 0x000056180353128d in aio_wait_bh_oneshot (ctx=0x5618056c7580,
cb=<optimized out>, opaque=<optimized out>)
at /build/qemu-6MF7tq/qemu-5.0.1/util/aio-wait.c:71
#7 0x000056180345c50a in bdrv_attach_aio_context (new_context=0x5618056c7580,
bs=0x561805ed4c00) at /build/qemu-6MF7tq/qemu-5.0.1/block.c:6172
#8 bdrv_set_aio_context_ignore (bs=bs@entry=0x561805ed4c00,
new_context=new_context@entry=0x5618056c7580,
ignore=ignore@entry=0x7f60e1e63780)
at /build/qemu-6MF7tq/qemu-5.0.1/block.c:6237
#9 0x000056180345c969 in bdrv_child_try_set_aio_context (
bs=bs@entry=0x561805ed4c00, ctx=0x5618056c7580,
ignore_child=<optimized out>, errp=<optimized out>)
at /build/qemu-6MF7tq/qemu-5.0.1/block.c:6332
#10 0x00005618034957db in blk_do_set_aio_context (blk=0x56180695b3f0,
new_context=0x5618056c7580, update_root_node=update_root_node@entry=true,
errp=errp@entry=0x0)
at /build/qemu-6MF7tq/qemu-5.0.1/block/block-backend.c:1989
#11 0x00005618034980bd in blk_set_aio_context (blk=<optimized out>,
new_context=<optimized out>, errp=errp@entry=0x0)
at /build/qemu-6MF7tq/qemu-5.0.1/block/block-backend.c:2010
#12 0x0000561803197953 in virtio_blk_data_plane_stop (vdev=<optimized out>)
at /build/qemu-6MF7tq/qemu-5.0.1/hw/block/dataplane/virtio-blk.c:292
#13 0x00005618033d67bf in virtio_bus_stop_ioeventfd (bus=0x5618056d9f08)
at /build/qemu-6MF7tq/qemu-5.0.1/hw/virtio/virtio-bus.c:245
#14 0x00005618031c9b2e in virtio_vmstate_change (opaque=0x5618056d9f90,
running=0, state=<optimized out>)
at /build/qemu-6MF7tq/qemu-5.0.1/hw/virtio/virtio.c:3220
#15 0x0000561803208bfd in vm_state_notify (running=running@entry=0,
state=state@entry=RUN_STATE_FINISH_MIGRATE)
at /build/qemu-6MF7tq/qemu-5.0.1/softmmu/vl.c:1275
#16 0x0000561803155c02 in do_vm_stop (state=RUN_STATE_FINISH_MIGRATE,
send_stop=<optimized out>) at /build/qemu-6MF7tq/qemu-5.0.1/cpus.c:1032
#17 0x00005618033e3765 in migration_completion (s=0x5618056e6960)
at /build/qemu-6MF7tq/qemu-5.0.1/migration/migration.c:2914
#18 migration_iteration_run (s=0x5618056e6960)
at /build/qemu-6MF7tq/qemu-5.0.1/migration/migration.c:3275
#19 migration_thread (opaque=opaque@entry=0x5618056e6960)
at /build/qemu-6MF7tq/qemu-5.0.1/migration/migration.c:3439
#20 0x0000561803536ad6 in qemu_thread_start (args=<optimized out>)
at /build/qemu-6MF7tq/qemu-5.0.1/util/qemu-thread-posix.c:519
#21 0x00007f61085d06ba in start_thread ()
from /lib/x86_64-linux-gnu/libpthread.so.0
#22 0x00007f610830641d in sysctl () from /lib/x86_64-linux-gnu/libc.so.6
#23 0x0000000000000000 in ?? ()
Fix it by checking that the iochannel is non-null before trying to
detach it from the aio_context. If it is null, no detaching is needed,
and it will get reattached in the proper aio_context once the connection
is reestablished.
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210129073859.683063-2-rvkagan@yandex-team.ru>
Signed-off-by: Eric Blake <eblake@redhat.com>
Register a yank function which shuts down the socket and sets
s->state = NBD_CLIENT_QUIT. This is the same behaviour as if an
error occured.
Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <b73eb07db6d1fcd00667beb13ae6117260f002c3.1609167865.git.lukasstraub2@web.de>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This commit is the result of running the timer-del-timer-free.cocci
script on the whole source tree.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20201215154107.3255-4-peter.maydell@linaro.org
Allow the server to expose an additional metacontext to be requested
by savvy clients. qemu-nbd adds a new option -A to expose the
qemu:allocation-depth metacontext through NBD_CMD_BLOCK_STATUS; this
can also be set via QMP when using block-export-add.
qemu as client is hacked into viewing the key aspects of this new
context by abusing the already-experimental x-dirty-bitmap option to
collapse all depths greater than 2, which results in a tri-state value
visible in the output of 'qemu-img map --output=json' (yes, that means
x-dirty-bitmap is now a bit of a misnomer, but I didn't feel like
renaming it as it would introduce a needless break of back-compat,
even though we make no compat guarantees with x- members):
unallocated (depth 0) => "zero":false, "data":true
local (depth 1) => "zero":false, "data":false
backing (depth 2+) => "zero":true, "data":true
libnbd as client is probably a nicer way to get at the information
without having to decipher such hacks in qemu as client. ;)
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20201027050556.269064-11-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
In a recent commit 12c75e20a2 we've improved
nbd_co_reconnect_loop() to not make drain wait for additional sleep.
Similarly, we shouldn't try to connect, if previous sleep was
interrupted by drain begin, otherwise drain_begin will have to wait for
the whole connection attempt.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200903190301.367620-5-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
reconnect-delay has a design flaw: we handle it in the same loop where
we do connection attempt. So, reconnect-delay may be exceeded by
unpredictable time of connection attempt.
Let's instead use separate timer.
How to reproduce the bug:
1. Create an image on node1:
qemu-img create -f qcow2 xx 100M
2. Start NBD server on node1:
qemu-nbd xx
3. On node2 start qemu-io:
./build/qemu-io --image-opts \
driver=nbd,server.type=inet,server.host=192.168.100.5,server.port=10809,reconnect-delay=15
4. Type 'read 0 512' in qemu-io interface to check that connection
works
Be careful: you should make steps 5-7 in a short time, less than 15
seconds.
5. Kill nbd server on node1
6. Run 'read 0 512' in qemu-io interface again, to be sure that nbd
client goes to reconnect loop.
7. On node1 run the following command
sudo iptables -A INPUT -p tcp --dport 10809 -j DROP
This will make the connect() call of qemu-io at node2 take a long time.
And you'll see that read command in qemu-io will hang for a long time,
more than 15 seconds specified by reconnect-delay parameter. It's the
bug.
8. Don't forget to drop iptables rule on node1:
sudo iptables -D INPUT -p tcp --dport 10809 -j DROP
Important note: Step [5] is necessary to reproduce _this_ bug. If we
miss step [5], the read command (step 6) will hang for a long time and
this commit doesn't help, because there will be not long connect() to
unreachable host, but long sendmsg() to unreachable host, which should
be fixed by enabling and adjusting keep-alive on the socket, which is a
thing for further patch set.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200903190301.367620-4-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Don't use nbd_client_detach_aio_context() driver handler where we want
to finalize the connection. We should directly use
qio_channel_detach_aio_context() in such cases. Driver handler may (and
will) contain another things, unrelated to the qio channel.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200903190301.367620-3-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
We pause reconnect process during drained section. So, if we have some
requests, waiting for reconnect we should cancel them, otherwise they
deadlock the drained section.
How to reproduce:
1. Create an image:
qemu-img create -f qcow2 xx 100M
2. Start NBD server:
qemu-nbd xx
3. Start vm with second nbd disk on node2, like this:
./build/x86_64-softmmu/qemu-system-x86_64 -nodefaults -drive \
file=/work/images/cent7.qcow2 -drive \
driver=nbd,server.type=inet,server.host=192.168.100.5,server.port=10809,reconnect-delay=60 \
-vnc :0 -m 2G -enable-kvm -vga std
4. Access the vm through vnc (or some other way?), and check that NBD
drive works:
dd if=/dev/sdb of=/dev/null bs=1M count=10
- the command should succeed.
5. Now, kill the nbd server, and run dd in the guest again:
dd if=/dev/sdb of=/dev/null bs=1M count=10
Now Qemu is trying to reconnect, and dd-generated requests are waiting
for the connection (they will wait up to 60 seconds (see
reconnect-delay option above) and than fail). But suddenly, vm may
totally hang in the deadlock. You may need to increase reconnect-delay
period to catch the dead-lock.
VM doesn't respond because drain dead-lock happens in cpu thread with
global mutex taken. That's not good thing by itself and is not fixed
by this commit (true way is using iothreads). Still this commit fixes
drain dead-lock itself.
Note: probably, we can instead continue to reconnect during drained
section. To achieve this, we may move negotiation to the connect thread
to make it independent of bs aio context. But expanding drained section
doesn't seem good anyway. So, let's now fix the bug the simplest way.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200903190301.367620-2-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
This makes nbd's connection_co yield during reconnects, so that
reconnect doesn't block the main thread. This is very important in
case of an unavailable nbd server host: connect() call may take a long
time, blocking the main thread (and due to reconnect, it will hang
again and again with small gaps of working time during pauses between
connection attempts).
Realization notes:
- We don't want to implement non-blocking connect() over non-blocking
socket, because getaddrinfo() doesn't have portable non-blocking
realization anyway, so let's just use a thread for both getaddrinfo()
and connect().
- We can't use qio_channel_socket_connect_async (which behaves
similarly and starts a thread to execute connect() call), as it's relying
on someone iterating main loop (g_main_loop_run() or something like
this), which is not always the case.
- We can't use thread_pool_submit_co API, as thread pool waits for all
threads to finish (but we don't want to wait for blocking reconnect
attempt on shutdown.
So, we just create the thread by hand. Some additional difficulties
are:
- We want our connect to avoid blocking drained sections and aio context
switches. To achieve this, we make it possible to "cancel" synchronous
wait for the connect (which is a coroutine yield actually), still,
the thread continues in background, and if successful, its result may be
reused on next reconnect attempt.
- We don't want to wait for reconnect on shutdown, so there is
CONNECT_THREAD_RUNNING_DETACHED thread state, which means that the block
layer is no longer interested in a result, and thread should close new
connected socket on finish and free the state.
How to reproduce the bug, fixed with this commit:
1. Create an image on node1:
qemu-img create -f qcow2 xx 100M
2. Start NBD server on node1:
qemu-nbd xx
3. Start vm with second nbd disk on node2, like this:
./x86_64-softmmu/qemu-system-x86_64 -nodefaults -drive \
file=/work/images/cent7.qcow2 -drive file=nbd+tcp://192.168.100.2 \
-vnc :0 -qmp stdio -m 2G -enable-kvm -vga std
4. Access the vm through vnc (or some other way?), and check that NBD
drive works:
dd if=/dev/sdb of=/dev/null bs=1M count=10
- the command should succeed.
5. Now, let's trigger nbd-reconnect loop in Qemu process. For this:
5.1 Kill NBD server on node1
5.2 run "dd if=/dev/sdb of=/dev/null bs=1M count=10" in the guest
again. The command should fail and a lot of error messages about
failing disk may appear as well.
Now NBD client driver in Qemu tries to reconnect.
Still, VM works well.
6. Make node1 unavailable on NBD port, so connect() from node2 will
last for a long time:
On node1 (Note, that 10809 is just a default NBD port):
sudo iptables -A INPUT -p tcp --dport 10809 -j DROP
After some time the guest hangs, and you may check in gdb that Qemu
hangs in connect() call, issued from the main thread. This is the
BUG.
7. Don't forget to drop iptables rule from your node1:
sudo iptables -D INPUT -p tcp --dport 10809 -j DROP
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200812145237.4396-1-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: minor wording and formatting tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
We try to go to wakeable sleep, so that, if drain begins it will break
the sleep. But what if nbd_client_co_drain_begin() already called and
s->drained is already true? We'll go to sleep, and drain will have to
wait for the whole timeout. Let's improve it.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200727184751.15704-5-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
On shutdown nbd driver may be in a connecting state. We should shutdown
it as well, otherwise we may hang in
nbd_teardown_connection, waiting for conneciton_co to finish in
BDRV_POLL_WHILE(bs, s->connection_co) loop if remote server is down.
How to reproduce the dead lock:
1. Create nbd-fault-injector.conf with the following contents:
[inject-error "mega1"]
event=data
io=readwrite
when=before
2. In one terminal run nbd-fault-injector in a loop, like this:
n=1; while true; do
echo $n; ((n++));
./nbd-fault-injector.py 127.0.0.1:10000 nbd-fault-injector.conf;
done
3. In another terminal run qemu-io in a loop, like this:
n=1; while true; do
echo $n; ((n++));
./qemu-io -c 'read 0 512' nbd://127.0.0.1:10000;
done
After some time, qemu-io will hang. Note, that this hang may be
triggered by another bug, so the whole case is fixed only together with
commit "block/nbd: allow drain during reconnect attempt".
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200727184751.15704-4-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
It should be safe to reenter qio_channel_yield() on io/channel read/write
path, so it's safe to reduce in_flight and allow attaching new aio
context. And no problem to allow drain itself: connection attempt is
not a guest request. Moreover, if remote server is down, we can hang
in negotiation, blocking drain section and provoking a dead lock.
How to reproduce the dead lock:
1. Create nbd-fault-injector.conf with the following contents:
[inject-error "mega1"]
event=data
io=readwrite
when=before
2. In one terminal run nbd-fault-injector in a loop, like this:
n=1; while true; do
echo $n; ((n++));
./nbd-fault-injector.py 127.0.0.1:10000 nbd-fault-injector.conf;
done
3. In another terminal run qemu-io in a loop, like this:
n=1; while true; do
echo $n; ((n++));
./qemu-io -c 'read 0 512' nbd://127.0.0.1:10000;
done
After some time, qemu-io will hang trying to drain, for example, like
this:
#3 aio_poll (ctx=0x55f006bdd890, blocking=true) at
util/aio-posix.c:600
#4 bdrv_do_drained_begin (bs=0x55f006bea710, recursive=false,
parent=0x0, ignore_bds_parents=false, poll=true) at block/io.c:427
#5 bdrv_drained_begin (bs=0x55f006bea710) at block/io.c:433
#6 blk_drain (blk=0x55f006befc80) at block/block-backend.c:1710
#7 blk_unref (blk=0x55f006befc80) at block/block-backend.c:498
#8 bdrv_open_inherit (filename=0x7fffba1563bc
"nbd+tcp://127.0.0.1:10000", reference=0x0, options=0x55f006be86d0,
flags=24578, parent=0x0, child_class=0x0, child_role=0,
errp=0x7fffba154620) at block.c:3491
#9 bdrv_open (filename=0x7fffba1563bc "nbd+tcp://127.0.0.1:10000",
reference=0x0, options=0x0, flags=16386, errp=0x7fffba154620) at
block.c:3513
#10 blk_new_open (filename=0x7fffba1563bc "nbd+tcp://127.0.0.1:10000",
reference=0x0, options=0x0, flags=16386, errp=0x7fffba154620) at
block/block-backend.c:421
And connection_co stack like this:
#0 qemu_coroutine_switch (from_=0x55f006bf2650, to_=0x7fe96e07d918,
action=COROUTINE_YIELD) at util/coroutine-ucontext.c:302
#1 qemu_coroutine_yield () at util/qemu-coroutine.c:193
#2 qio_channel_yield (ioc=0x55f006bb3c20, condition=G_IO_IN) at
io/channel.c:472
#3 qio_channel_readv_all_eof (ioc=0x55f006bb3c20, iov=0x7fe96d729bf0,
niov=1, errp=0x7fe96d729eb0) at io/channel.c:110
#4 qio_channel_readv_all (ioc=0x55f006bb3c20, iov=0x7fe96d729bf0,
niov=1, errp=0x7fe96d729eb0) at io/channel.c:143
#5 qio_channel_read_all (ioc=0x55f006bb3c20, buf=0x7fe96d729d28
"\300.\366\004\360U", buflen=8, errp=0x7fe96d729eb0) at
io/channel.c:247
#6 nbd_read (ioc=0x55f006bb3c20, buffer=0x7fe96d729d28, size=8,
desc=0x55f004f69644 "initial magic", errp=0x7fe96d729eb0) at
/work/src/qemu/master/include/block/nbd.h:365
#7 nbd_read64 (ioc=0x55f006bb3c20, val=0x7fe96d729d28,
desc=0x55f004f69644 "initial magic", errp=0x7fe96d729eb0) at
/work/src/qemu/master/include/block/nbd.h:391
#8 nbd_start_negotiate (aio_context=0x55f006bdd890,
ioc=0x55f006bb3c20, tlscreds=0x0, hostname=0x0,
outioc=0x55f006bf19f8, structured_reply=true,
zeroes=0x7fe96d729dca, errp=0x7fe96d729eb0) at nbd/client.c:904
#9 nbd_receive_negotiate (aio_context=0x55f006bdd890,
ioc=0x55f006bb3c20, tlscreds=0x0, hostname=0x0,
outioc=0x55f006bf19f8, info=0x55f006bf1a00, errp=0x7fe96d729eb0) at
nbd/client.c:1032
#10 nbd_client_connect (bs=0x55f006bea710, errp=0x7fe96d729eb0) at
block/nbd.c:1460
#11 nbd_reconnect_attempt (s=0x55f006bf19f0) at block/nbd.c:287
#12 nbd_co_reconnect_loop (s=0x55f006bf19f0) at block/nbd.c:309
#13 nbd_connection_entry (opaque=0x55f006bf19f0) at block/nbd.c:360
#14 coroutine_trampoline (i0=113190480, i1=22000) at
util/coroutine-ucontext.c:173
Note, that the hang may be
triggered by another bug, so the whole case is fixed only together with
commit "block/nbd: on shutdown terminate connection attempt".
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200727184751.15704-3-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
We are going to implement non-blocking version of
nbd_establish_connection, which for a while will be used only for
nbd_reconnect_attempt, not for nbd_open, so we need to call it
separately.
Refactor nbd_reconnect_attempt in a way which makes next commit
simpler.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200727184751.15704-2-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
When converting to qcow2 compressed format, the last step is a special
zero length compressed write, ending in a call to bdrv_co_truncate(). This
call always fails for the nbd driver since it does not implement
bdrv_co_truncate().
For block devices, which have the same limits, the call succeeds since
the file driver implements bdrv_co_truncate(). If the caller asked to
truncate to the same or smaller size with exact=false, the truncate
succeeds. Implement the same logic for nbd.
Example failing without this change:
In one shell start qemu-nbd:
$ truncate -s 1g test.tar
$ qemu-nbd --socket=/tmp/nbd.sock --persistent --format=raw --offset 1536 test.tar
In another shell convert an image to qcow2 compressed via NBD:
$ echo "disk data" > disk.raw
$ truncate -s 1g disk.raw
$ qemu-img convert -f raw -O qcow2 -c disk1.raw nbd+unix:///?socket=/tmp/nbd.sock; echo $?
1
qemu-img failed, but the conversion was successful:
$ qemu-img info nbd+unix:///?socket=/tmp/nbd.sock
image: nbd+unix://?socket=/tmp/nbd.sock
file format: qcow2
virtual size: 1 GiB (1073741824 bytes)
...
$ qemu-img check nbd+unix:///?socket=/tmp/nbd.sock
No errors were found on the image.
1/16384 = 0.01% allocated, 100.00% fragmented, 100.00% compressed clusters
Image end offset: 393216
$ qemu-img compare disk.raw nbd+unix:///?socket=/tmp/nbd.sock
Images are identical.
Fixes: https://bugzilla.redhat.com/1860627
Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Message-Id: <20200727215846.395443-2-nsoffer@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[eblake: typo fixes]
Signed-off-by: Eric Blake <eblake@redhat.com>
When snprintf returns the same value as the buffer size, the final
byte was truncated to ensure a NUL terminator. Fortunately, such long
export names are unusual enough, with no real impact other than what
is displayed to the user.
Fixes: 5c86bdf120
Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200622210355.414941-1-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
If we want to check error after errp-function call, we need to
introduce local_err and then propagate it to errp. Instead, use
the ERRP_GUARD() macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_GUARD() leaves errp as is if it's not NULL or
&error_fatal, this means that we don't break error_abort
(we'll abort on error_set, not on error_propagate)
If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_GUARD() macro.
Otherwise, this info will not be added when errp == &error_fatal
(the program will exit prior to the error_append_hint() or
error_prepend() call). Fix several such cases, e.g. in nbd_read().
This commit is generated by command
sed -n '/^Network Block Device (NBD)$/,/^$/{s/^F: //p}' \
MAINTAINERS | \
xargs git ls-files | grep '\.[hc]$' | \
xargs spatch \
--sp-file scripts/coccinelle/errp-guard.cocci \
--macro-file scripts/cocci-macro-file.h \
--in-place --no-show-diff --max-width 80
Reported-by: Kevin Wolf <kwolf@redhat.com>
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200707165037.1026246-8-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[ERRP_AUTO_PROPAGATE() renamed to ERRP_GUARD(), and
auto-propagated-errp.cocci to errp-guard.cocci. Commit message
tweaked again.]
When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away. The previous commit did that with a Coccinelle script I
consider fairly trustworthy. This commit uses the same script with
the matching of return taken out, i.e. we convert
if (!foo(..., &err)) {
...
error_propagate(errp, err);
...
}
to
if (!foo(..., errp)) {
...
...
}
This is unsound: @err could still be read between afterwards. I don't
know how to express "no read of @err without an intervening write" in
Coccinelle. Instead, I manually double-checked for uses of @err.
Suboptimal line breaks tweaked manually. qdev_realize() simplified
further to placate scripts/checkpatch.pl.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-36-armbru@redhat.com>
The previous commit enables conversion of
visit_foo(..., &err);
if (err) {
...
}
to
if (!visit_foo(..., errp)) {
...
}
for visitor functions that now return true / false on success / error.
Coccinelle script:
@@
identifier fun =~ "check_list|input_type_enum|lv_start_struct|lv_type_bool|lv_type_int64|lv_type_str|lv_type_uint64|output_type_enum|parse_type_bool|parse_type_int64|parse_type_null|parse_type_number|parse_type_size|parse_type_str|parse_type_uint64|print_type_bool|print_type_int64|print_type_null|print_type_number|print_type_size|print_type_str|print_type_uint64|qapi_clone_start_alternate|qapi_clone_start_list|qapi_clone_start_struct|qapi_clone_type_bool|qapi_clone_type_int64|qapi_clone_type_null|qapi_clone_type_number|qapi_clone_type_str|qapi_clone_type_uint64|qapi_dealloc_start_list|qapi_dealloc_start_struct|qapi_dealloc_type_anything|qapi_dealloc_type_bool|qapi_dealloc_type_int64|qapi_dealloc_type_null|qapi_dealloc_type_number|qapi_dealloc_type_str|qapi_dealloc_type_uint64|qobject_input_check_list|qobject_input_check_struct|qobject_input_start_alternate|qobject_input_start_list|qobject_input_start_struct|qobject_input_type_any|qobject_input_type_bool|qobject_input_type_bool_keyval|qobject_input_type_int64|qobject_input_type_int64_keyval|qobject_input_type_null|qobject_input_type_number|qobject_input_type_number_keyval|qobject_input_type_size_keyval|qobject_input_type_str|qobject_input_type_str_keyval|qobject_input_type_uint64|qobject_input_type_uint64_keyval|qobject_output_start_list|qobject_output_start_struct|qobject_output_type_any|qobject_output_type_bool|qobject_output_type_int64|qobject_output_type_null|qobject_output_type_number|qobject_output_type_str|qobject_output_type_uint64|start_list|visit_check_list|visit_check_struct|visit_start_alternate|visit_start_list|visit_start_struct|visit_type_.*";
expression list args;
typedef Error;
Error *err;
@@
- fun(args, &err);
- if (err)
+ if (!fun(args, &err))
{
...
}
A few line breaks tidied up manually.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200707160613.848843-19-armbru@redhat.com>
Commit 93676c88 relaxed our NBD client code to request export names up
to the NBD protocol maximum of 4096 bytes without NUL terminator, even
though the block layer can't store anything longer than 4096 bytes
including NUL terminator for display to the user. Since this means
there are some export names where we have to truncate things, we can
at least try to make the truncation a bit more obvious for the user.
Note that in spite of the truncated display name, we can still
communicate with an NBD server using such a long export name; this was
deemed nicer than refusing to even connect to such a server (since the
server may not be under our control, and since determining our actual
length limits gets tricky when nbd://host:port/export and
nbd+unix:///export?socket=/path are themselves variable-length
expansions beyond the export name but count towards the block layer
name length).
Reported-by: Xueqiang Wei <xuwei@redhat.com>
Fixes: https://bugzilla.redhat.com/1843684
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200610163741.3745251-3-eblake@redhat.com>
The NBD spec was updated (see nbd.git commit 9f30fedb) so that
max_block doesn't relate to NBD_CMD_TRIM. So, drop the restriction.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200401150112.9557-3-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: tweak commit message to call out NBD commit]
Signed-off-by: Eric Blake <eblake@redhat.com>
The NBD spec was updated (see nbd.git commit 9f30fedb) so that
max_block doesn't relate to NBD_CMD_BLOCK_STATUS. So, drop the
restriction.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200401150112.9557-2-vsementsov@virtuozzo.com>
[eblake: tweak commit message to call out NBD commit]
Signed-off-by: Eric Blake <eblake@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>
In currently implementation there will be a memory leak when
nbd_client_connect() returns error status. Here is an easy way to
reproduce:
1. run qemu-iotests as follow and check the result with asan:
./check -raw 143
Following is the asan output backtrack:
Direct leak of 40 byte(s) in 1 object(s) allocated from:
#0 0x7f629688a560 in calloc (/usr/lib64/libasan.so.3+0xc7560)
#1 0x7f6295e7e015 in g_malloc0 (/usr/lib64/libglib-2.0.so.0+0x50015)
#2 0x56281dab4642 in qobject_input_start_struct /mnt/sdb/qemu-4.2.0-rc0/qapi/qobject-input-visitor.c:295
#3 0x56281dab1a04 in visit_start_struct /mnt/sdb/qemu-4.2.0-rc0/qapi/qapi-visit-core.c:49
#4 0x56281dad1827 in visit_type_SocketAddress qapi/qapi-visit-sockets.c:386
#5 0x56281da8062f in nbd_config /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1716
#6 0x56281da8062f in nbd_process_options /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1829
#7 0x56281da8062f in nbd_open /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1873
Direct leak of 15 byte(s) in 1 object(s) allocated from:
#0 0x7f629688a3a0 in malloc (/usr/lib64/libasan.so.3+0xc73a0)
#1 0x7f6295e7dfbd in g_malloc (/usr/lib64/libglib-2.0.so.0+0x4ffbd)
#2 0x7f6295e96ace in g_strdup (/usr/lib64/libglib-2.0.so.0+0x68ace)
#3 0x56281da804ac in nbd_process_options /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1834
#4 0x56281da804ac in nbd_open /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1873
Indirect leak of 24 byte(s) in 1 object(s) allocated from:
#0 0x7f629688a3a0 in malloc (/usr/lib64/libasan.so.3+0xc73a0)
#1 0x7f6295e7dfbd in g_malloc (/usr/lib64/libglib-2.0.so.0+0x4ffbd)
#2 0x7f6295e96ace in g_strdup (/usr/lib64/libglib-2.0.so.0+0x68ace)
#3 0x56281dab41a3 in qobject_input_type_str_keyval /mnt/sdb/qemu-4.2.0-rc0/qapi/qobject-input-visitor.c:536
#4 0x56281dab2ee9 in visit_type_str /mnt/sdb/qemu-4.2.0-rc0/qapi/qapi-visit-core.c:297
#5 0x56281dad0fa1 in visit_type_UnixSocketAddress_members qapi/qapi-visit-sockets.c:141
#6 0x56281dad17b6 in visit_type_SocketAddress_members qapi/qapi-visit-sockets.c:366
#7 0x56281dad186a in visit_type_SocketAddress qapi/qapi-visit-sockets.c:393
#8 0x56281da8062f in nbd_config /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1716
#9 0x56281da8062f in nbd_process_options /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1829
#10 0x56281da8062f in nbd_open /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1873
Fixes: 8f071c9db5
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: qemu-stable <qemu-stable@nongnu.org>
Cc: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <1575517528-44312-3-git-send-email-pannengyuan@huawei.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
The BDRVNBDState cleanup code is common in two places, add
nbd_clear_bdrvstate() function to do these cleanups.
Suggested-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <1575517528-44312-2-git-send-email-pannengyuan@huawei.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: fix compilation error and commit message]
Signed-off-by: Eric Blake <eblake@redhat.com>
The NBD URI specification [1] states that only one leading slash at
the beginning of the URI path component is stripped, not all such
slashes. This becomes important to a patch I just proposed to nbdkit
[2], which would allow the exportname to select a file embedded within
an ext2 image: ext2fs demands an absolute pathname beginning with '/',
and because qemu was inadvertantly stripping it, my nbdkit patch had
to work around the behavior.
[1] https://github.com/NetworkBlockDevice/nbd/blob/master/doc/uri.md
[2] https://www.redhat.com/archives/libguestfs/2020-February/msg00109.html
Note that the qemu bug only affects handling of URIs such as
nbd://host:port//abs/path (where '/abs/path' should be the export
name); it is still possible to use --image-opts and pass the desired
export name with a leading slash directly through JSON even without
this patch.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200212023101.1162686-1-eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
When nbd_close() is called from a coroutine, the connection_co never
gets to run, and thus nbd_teardown_connection() hangs.
This is because aio_co_enter() only puts the connection_co into the main
coroutine's wake-up queue, so this main coroutine needs to yield and
wait for connection_co to terminate.
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200122164532.178040-2-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
All callers of nbd_iter_channel_error() pass the address of a
local_err variable, and only call this function if an error has
already occurred, using this function to propagate that error.
This is already implied by its name (local_err instead of the classic
errp), but it is worth additionally stressing this by adding an
assertion to make it part of the function contract.
The local_err parameter is not here to return information about
nbd_iter_channel_error failure. Instead it's assumed to be filled when
passed to the function. This is already stressed by its name
(local_err, instead of classic errp). Stress it additionally by
assertion.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20191205174635.18758-22-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Qemu as server currently won't accept export names larger than 256
bytes, nor create dirty bitmap names longer than 1023 bytes, so most
uses of qemu as client or server have no reason to get anywhere near
the NBD spec maximum of a 4k limit per string.
However, we weren't actually enforcing things, ignoring when the
remote side violates the protocol on input, and also having several
code paths where we send oversize strings on output (for example,
qemu-nbd --description could easily send more than 4k). Tighten
things up as follows:
client:
- Perform bounds check on export name and dirty bitmap request prior
to handing it to server
- Validate that copied server replies are not too long (ignoring
NBD_INFO_* replies that are not copied is not too bad)
server:
- Perform bounds check on export name and description prior to
advertising it to client
- Reject client name or metadata query that is too long
- Adjust things to allow full 4k name limit rather than previous
256 byte limit
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20191114024635.11363-4-eblake@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Implement reconnect. To achieve this:
1. add new modes:
connecting-wait: means, that reconnecting is in progress, and there
were small number of reconnect attempts, so all requests are
waiting for the connection.
connecting-nowait: reconnecting is in progress, there were a lot of
attempts of reconnect, all requests will return errors.
two old modes are used too:
connected: normal state
quit: exiting after fatal error or on close
Possible transitions are:
* -> quit
connecting-* -> connected
connecting-wait -> connecting-nowait (transition is done after
reconnect-delay seconds in connecting-wait mode)
connected -> connecting-wait
2. Implement reconnect in connection_co. So, in connecting-* mode,
connection_co, tries to reconnect unlimited times.
3. Retry nbd queries on channel error, if we are in connecting-wait
state.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20191009084158.15614-3-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
The client side is fairly straightforward: if the server advertised
fast zero support, then we can map that to BDRV_REQ_NO_FALLBACK
support. A server that advertises FAST_ZERO but not WRITE_ZEROES
is technically broken, but we can ignore that situation as it does
not change our behavior.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190823143726.27062-4-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Thanks to our recent move to use glib's g_autofree, I can join the
bandwagon. Getting rid of gotos is fun ;)
There are probably more places where we could register cleanup
functions and get rid of more gotos; this patch just focuses on the
labels that existed merely to call g_free.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190824172813.29720-2-eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
