The AioContext lock no longer exists.
There is one noteworthy change:
- * More specifically, these functions use BDRV_POLL_WHILE(bs), which
- * requires the caller to be either in the main thread and hold
- * the BlockdriverState (bs) AioContext lock, or directly in the
- * home thread that runs the bs AioContext. Calling them from
- * another thread in another AioContext would cause deadlocks.
+ * More specifically, these functions use BDRV_POLL_WHILE(bs), which requires
+ * the caller to be either in the main thread or directly in the home thread
+ * that runs the bs AioContext. Calling them from another thread in another
+ * AioContext would cause deadlocks.
I am not sure whether deadlocks are still possible. Maybe they have just
moved to the fine-grained locks that have replaced the AioContext. Since
I am not sure if the deadlocks are gone, I have kept the substance
unchanged and just removed mention of the AioContext.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20231205182011.1976568-15-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is the big patch that removes
aio_context_acquire()/aio_context_release() from the block layer and
affected block layer users.
There isn't a clean way to split this patch and the reviewers are likely
the same group of people, so I decided to do it in one patch.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-ID: <20231205182011.1976568-7-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The vhost-user-blk export implement AioContext switches in its drain
implementation. This means that on drain_begin, it detaches the server
from its AioContext and on drain_end, attaches it again and schedules
the server->co_trip coroutine in the updated AioContext.
However, nothing guarantees that server->co_trip is even safe to be
scheduled. Not only is it unclear that the coroutine is actually in a
state where it can be reentered externally without causing problems, but
with two consecutive drains, it is possible that the scheduled coroutine
didn't have a chance yet to run and trying to schedule an already
scheduled coroutine a second time crashes with an assertion failure.
Following the model of NBD, this commit makes the vhost-user-blk export
shut down server->co_trip during drain so that resuming the export means
creating and scheduling a new coroutine, which is always safe.
There is one exception: If the drain call didn't poll (for example, this
happens in the context of bdrv_graph_wrlock()), then the coroutine
didn't have a chance to shut down. However, in this case the AioContext
can't have changed; changing the AioContext always involves a polling
drain. So in this case we can simply assert that the AioContext is
unchanged and just leave the coroutine running or wake it up if it has
yielded to wait for the AioContext to be attached again.
Fixes: e1054cd4aa
Fixes: https://issues.redhat.com/browse/RHEL-1708
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231127115755.22846-1-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_first_blk() and bdrv_is_root_node() need to hold a reader lock
for the graph. These functions are the only functions in block-backend.c
that access the parent list of a node.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230929145157.45443-5-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Slave/master nomenclature was replaced with backend/frontend in commit
1fc19b6527 ("vhost-user: Adopt new backend naming")
This patch replaces all remaining uses of master and slave in the
codebase.
Signed-off-by: Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-Id: <20230613080849.2115347-1-manos.pitsidianakis@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
All callers now pass is_external=false to aio_set_fd_handler() and
aio_set_event_notifier(). The aio_disable_external() API that
temporarily disables fd handlers that were registered is_external=true
is therefore dead code.
Remove aio_disable_external(), aio_enable_external(), and the
is_external arguments to aio_set_fd_handler() and
aio_set_event_notifier().
The entire test-fdmon-epoll test is removed because its sole purpose was
testing aio_disable_external().
Parts of this patch were generated using the following coccinelle
(https://coccinelle.lip6.fr/) semantic patch:
@@
expression ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque;
@@
- aio_set_fd_handler(ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque)
+ aio_set_fd_handler(ctx, fd, io_read, io_write, io_poll, io_poll_ready, opaque)
@@
expression ctx, notifier, is_external, io_read, io_poll, io_poll_ready;
@@
- aio_set_event_notifier(ctx, notifier, is_external, io_read, io_poll, io_poll_ready)
+ aio_set_event_notifier(ctx, notifier, io_read, io_poll, io_poll_ready)
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230516190238.8401-21-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is part of ongoing work to remove the aio_disable_external() API.
Use BlockDevOps .drained_begin/end/poll() instead of
aio_set_fd_handler(is_external=true).
As a side-effect the FUSE export now follows AioContext changes like the
other export types.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-16-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The FUSE export calls blk_exp_ref/unref() without the AioContext lock.
Instead of fixing the FUSE export, adjust blk_exp_ref/unref() so they
work without the AioContext lock. This way it's less error-prone.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-15-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
vduse_blk_detach_ctx() waits for in-flight requests using
AIO_WAIT_WHILE(). This is not allowed according to a comment in
bdrv_set_aio_context_commit():
/*
* Take the old AioContex when detaching it from bs.
* At this point, new_context lock is already acquired, and we are now
* also taking old_context. This is safe as long as bdrv_detach_aio_context
* does not call AIO_POLL_WHILE().
*/
Use this opportunity to rewrite the drain code in vduse-blk:
- Use the BlockExport refcount so that vduse_blk_exp_delete() is only
called when there are no more requests in flight.
- Implement .drained_poll() so in-flight request coroutines are stopped
by the time .bdrv_detach_aio_context() is called.
- Remove AIO_WAIT_WHILE() from vduse_blk_detach_ctx() to solve the
.bdrv_detach_aio_context() constraint violation. It's no longer
needed due to the previous changes.
- Always handle the VDUSE file descriptor, even in drained sections. The
VDUSE file descriptor doesn't submit I/O, so it's safe to handle it in
drained sections. This ensures that the VDUSE kernel code gets a fast
response.
- Suspend virtqueue fd handlers in .drained_begin() and resume them in
.drained_end(). This eliminates the need for the
aio_set_fd_handler(is_external=true) flag, which is being removed from
QEMU.
This is a long list but splitting it into individual commits would
probably lead to git bisect failures - the changes are all related.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-14-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
vhost-user activity must be suspended during bdrv_drained_begin/end().
This prevents new requests from interfering with whatever is happening
in the drained section.
Previously this was done using aio_set_fd_handler()'s is_external
argument. In a multi-queue block layer world the aio_disable_external()
API cannot be used since multiple AioContext may be processing I/O, not
just one.
Switch to BlockDevOps->drained_begin/end() callbacks.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-8-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Each vhost-user-blk request runs in a coroutine. When the BlockBackend
enters a drained section we need to enter a quiescent state. Currently
any in-flight requests race with bdrv_drained_begin() because it is
unaware of vhost-user-blk requests.
When blk_co_preadv/pwritev()/etc returns it wakes the
bdrv_drained_begin() thread but vhost-user-blk request processing has
not yet finished. The request coroutine continues executing while the
main loop thread thinks it is in a drained section.
One example where this is unsafe is for blk_set_aio_context() where
bdrv_drained_begin() is called before .aio_context_detached() and
.aio_context_attach(). If request coroutines are still running after
bdrv_drained_begin(), then the AioContext could change underneath them
and they race with new requests processed in the new AioContext. This
could lead to virtqueue corruption, for example.
(This example is theoretical, I came across this while reading the
code and have not tried to reproduce it.)
It's easy to make bdrv_drained_begin() wait for in-flight requests: add
a .drained_poll() callback that checks the VuServer's in-flight counter.
VuServer just needs an API that returns true when there are requests in
flight. The in-flight counter needs to be atomic.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-7-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The VuServer object has a refcount field and ref/unref APIs. The name is
confusing because it's actually an in-flight request counter instead of
a refcount.
Normally a refcount destroys the object upon reaching zero. The VuServer
counter is used to wake up the vhost-user coroutine when there are no
more requests.
Avoid confusing by renaming refcount and ref/unref to in_flight and
inc/dec.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-6-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There are some error paths in blk_exp_add() that jump to 'fail:' before
'exp' is even created. So we can't just unconditionally access exp->blk.
Add a NULL check, and switch from exp->blk to blk, which is available
earlier, just to be extra sure that we really cover all cases where
BlockDevOps could have been set for it (in practice, this only happens
in drv->create() today, so this part of the change isn't strictly
necessary).
Fixes: Coverity CID 1509238
Fixes: de79b52604
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230510203601.418015-3-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Most export types install BlockDeviceOps pointers. It is easy to forget
to remove them because that happens automatically via the "drive" qdev
property in hw/ but not block/export/.
Put blk_set_dev_ops(blk, NULL, NULL) calls in the core export.c code so
the export types don't need to remember.
This fixes the nbd and vhost-user-blk export types.
Fixes: fd6afc501a ("nbd/server: Use drained block ops to quiesce the server")
Fixes: ca858a5fe9 ("vhost-user-blk-server: notify client about disk resize")
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20230502211119.720647-1-stefanha@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
- Protect BlockBackend.queued_requests with its own lock
- Switch to AIO_WAIT_WHILE_UNLOCKED() where possible
- AioContext removal: LinuxAioState/LuringState/ThreadPool
- Add more coroutine_fn annotations, use bdrv/blk_co_*
- Fix crash when execute hmp_commit
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Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into staging
Block layer patches
- Protect BlockBackend.queued_requests with its own lock
- Switch to AIO_WAIT_WHILE_UNLOCKED() where possible
- AioContext removal: LinuxAioState/LuringState/ThreadPool
- Add more coroutine_fn annotations, use bdrv/blk_co_*
- Fix crash when execute hmp_commit
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# gpg: Signature made Tue 25 Apr 2023 02:12:29 PM BST
# gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg: issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
* tag 'for-upstream' of https://repo.or.cz/qemu/kevin: (25 commits)
block/monitor: Fix crash when executing HMP commit
vmdk: make vmdk_is_cid_valid a coroutine_fn
qcow2: mark various functions as coroutine_fn and GRAPH_RDLOCK
tests: mark more coroutine_fns
qemu-pr-helper: mark more coroutine_fns
9pfs: mark more coroutine_fns
nbd: mark more coroutine_fns, do not use co_wrappers
mirror: make mirror_flush a coroutine_fn, do not use co_wrappers
blkdebug: add missing coroutine_fn annotation
vvfat: mark various functions as coroutine_fn
thread-pool: avoid passing the pool parameter every time
thread-pool: use ThreadPool from the running thread
io_uring: use LuringState from the running thread
linux-aio: use LinuxAioState from the running thread
block: add missing coroutine_fn to bdrv_sum_allocated_file_size()
include/block: fixup typos
monitor: convert monitor_cleanup() to AIO_WAIT_WHILE_UNLOCKED()
hmp: convert handle_hmp_command() to AIO_WAIT_WHILE_UNLOCKED()
block: convert bdrv_drain_all_begin() to AIO_WAIT_WHILE_UNLOCKED()
block: convert bdrv_graph_wrlock() to AIO_WAIT_WHILE_UNLOCKED()
...
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
There is no change in behavior. Switch to AIO_WAIT_WHILE_UNLOCKED()
instead of AIO_WAIT_WHILE() to document that this code has already been
audited and converted. The AioContext argument is already NULL so
aio_context_release() is never called anyway.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230309190855.414275-3-stefanha@redhat.com>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Currently block_resize qmp command is simply ignored by vhost-user-blk
export. So, the block-node is successfully resized, but virtio config
is unchanged and guest doesn't see that disk is resized.
Let's handle the resize by modifying the config and notifying the guest
appropriately.
After this comment, lsblk in linux guest with attached
vhost-user-blk-pci device shows new size immediately after block_resize
QMP command on vhost-user exported block node.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-Id: <20230321201323.3695923-1-vsementsov@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
blk_get_geometry() eventually calls bdrv_nb_sectors(), which is a
co_wrapper_mixed_bdrv_rdlock. This means that when it is called from
coroutine context, it already assume to have the graph locked.
However, virtio_blk_sect_range_ok() in block/export/virtio-blk-handler.c
(used by vhost-user-blk and VDUSE exports) runs in a coroutine, but
doesn't take the graph lock - blk_*() functions are generally expected
to do that internally. This causes an assertion failure when accessing
an export for the first time if it runs in an iothread.
This is an example of the crash:
$ ./storage-daemon/qemu-storage-daemon --object iothread,id=th0 --blockdev file,filename=/home/kwolf/images/hd.img,node-name=disk --export vhost-user-blk,addr.type=unix,addr.path=/tmp/vhost.sock,node-name=disk,id=exp0,iothread=th0
qemu-storage-daemon: ../block/graph-lock.c:268: void assert_bdrv_graph_readable(void): Assertion `qemu_in_main_thread() || reader_count()' failed.
(gdb) bt
#0 0x00007ffff6eafe5c in __pthread_kill_implementation () from /lib64/libc.so.6
#1 0x00007ffff6e5fa76 in raise () from /lib64/libc.so.6
#2 0x00007ffff6e497fc in abort () from /lib64/libc.so.6
#3 0x00007ffff6e4971b in __assert_fail_base.cold () from /lib64/libc.so.6
#4 0x00007ffff6e58656 in __assert_fail () from /lib64/libc.so.6
#5 0x00005555556337a3 in assert_bdrv_graph_readable () at ../block/graph-lock.c:268
#6 0x00005555555fd5a2 in bdrv_co_nb_sectors (bs=0x5555564c5ef0) at ../block.c:5847
#7 0x00005555555ee949 in bdrv_nb_sectors (bs=0x5555564c5ef0) at block/block-gen.c:256
#8 0x00005555555fd6b9 in bdrv_get_geometry (bs=0x5555564c5ef0, nb_sectors_ptr=0x7fffef7fedd0) at ../block.c:5884
#9 0x000055555562ad6d in blk_get_geometry (blk=0x5555564cb200, nb_sectors_ptr=0x7fffef7fedd0) at ../block/block-backend.c:1624
#10 0x00005555555ddb74 in virtio_blk_sect_range_ok (blk=0x5555564cb200, block_size=512, sector=0, size=512) at ../block/export/virtio-blk-handler.c:44
#11 0x00005555555dd80d in virtio_blk_process_req (handler=0x5555564cbb98, in_iov=0x7fffe8003830, out_iov=0x7fffe8003860, in_num=1, out_num=0) at ../block/export/virtio-blk-handler.c:189
#12 0x00005555555dd546 in vu_blk_virtio_process_req (opaque=0x7fffe8003800) at ../block/export/vhost-user-blk-server.c:66
#13 0x00005555557bf4a1 in coroutine_trampoline (i0=-402635264, i1=32767) at ../util/coroutine-ucontext.c:177
#14 0x00007ffff6e75c20 in ?? () from /lib64/libc.so.6
#15 0x00007fffefffa870 in ?? ()
#16 0x0000000000000000 in ?? ()
Fix this by creating a new blk_co_get_geometry() that takes the lock,
and changing blk_get_geometry() to be a co_wrapper_mixed around it.
To make the resulting code cleaner, virtio-blk-handler.c can directly
call the coroutine version now (though that wouldn't be necessary for
fixing the bug, taking the lock in blk_co_get_geometry() is what fixes
it).
Fixes: 8ab8140a04
Reported-by: Lukáš Doktor <ldoktor@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230327113959.60071-1-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
fallocate(2) says about PUNCH_HOLE: "After a successful call, subsequent
reads from this range will return zeros." As it is, PUNCH_HOLE is
implemented as a call to blk_pdiscard(), which does not guarantee this.
We must call blk_pwrite_zeroes() instead. The difference to ZERO_RANGE
is that we pass the `BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK` flags to
the call -- the storage is supposed to be unmapped, and a slow fallback
by actually writing zeroes as data is not allowed.
Closes: https://gitlab.com/qemu-project/qemu/-/issues/1507
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230227104725.33511-2-hreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit was created with scripts/clean-includes.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230202133830.2152150-18-armbru@redhat.com>
We have two inclusion loops:
block/block.h
-> block/block-global-state.h
-> block/block-common.h
-> block/blockjob.h
-> block/block.h
block/block.h
-> block/block-io.h
-> block/block-common.h
-> block/blockjob.h
-> block/block.h
I believe these go back to Emanuele's reorganization of the block API,
merged a few months ago in commit d7e2fe4aac.
Fortunately, breaking them is merely a matter of deleting unnecessary
includes from headers, and adding them back in places where they are
now missing.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221221133551.3967339-2-armbru@redhat.com>
The has_FOO for pointer-valued FOO are redundant, except for arrays.
They are also a nuisance to work with. Recent commit "qapi: Start to
elide redundant has_FOO in generated C" provided the means to elide
them step by step. This is the step for qapi/block*.json.
Said commit explains the transformation in more detail.
There is one instance of the invariant violation mentioned there:
qcow2_signal_corruption() passes false, "" when node_name is an empty
string. Take care to pass NULL then.
The previous two commits cleaned up two more.
Additionally, helper bdrv_latency_histogram_stats() loses its output
parameters and returns a value instead.
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Hanna Reitz <hreitz@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221104160712.3005652-11-armbru@redhat.com>
[Fixes for #ifndef LIBRBD_SUPPORTS_ENCRYPTION and MacOS squashed in]
No functional change intended.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221025084952.2139888-11-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Swap 'buf' and 'bytes' around for consistency with
blk_co_{pread,pwrite}(), and in preparation to implement these functions
using generated_co_wrapper.
Callers were updated using this Coccinelle script:
@@ expression blk, offset, buf, bytes, flags; @@
- blk_pread(blk, offset, buf, bytes, flags)
+ blk_pread(blk, offset, bytes, buf, flags)
@@ expression blk, offset, buf, bytes, flags; @@
- blk_pwrite(blk, offset, buf, bytes, flags)
+ blk_pwrite(blk, offset, bytes, buf, flags)
It had no effect on hw/block/nand.c, presumably due to the #if, so that
file was updated manually.
Overly-long lines were then fixed by hand.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-4-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
For consistency with other I/O functions, and in preparation to
implement it using generated_co_wrapper.
Callers were updated using this Coccinelle script:
@@ expression blk, offset, buf, bytes; @@
- blk_pread(blk, offset, buf, bytes)
+ blk_pread(blk, offset, buf, bytes, 0)
It had no effect on hw/block/nand.c, presumably due to the #if, so that
file was updated manually.
Overly-long lines were then fixed by hand.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-3-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Currently we use 'id' option as the name of VDUSE device.
It's a bit confusing since we use one value for two different
purposes: the ID to identfy the export within QEMU (must be
distinct from any other exports in the same QEMU process, but
can overlap with names used by other processes), and the VDUSE
name to uniquely identify it on the host (must be distinct from
other VDUSE devices on the same host, but can overlap with other
export types like NBD in the same process). To make it clear,
this patch adds a separate 'name' option to specify the VDUSE
name for the vduse-blk export instead.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Message-Id: <20220614051532.92-7-xieyongji@bytedance.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add a 'serial' option to allow user to specify this value
explicitly. And the default value is changed to an empty
string as what we did in "hw/block/virtio-blk.c".
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Message-Id: <20220614051532.92-6-xieyongji@bytedance.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
To support reconnecting after restart or crash, VDUSE backend
might need to resubmit inflight I/Os. This stores the metadata
such as the index of inflight I/O's descriptors to a shm file so
that VDUSE backend can restore them during reconnecting.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Message-Id: <20220523084611.91-9-xieyongji@bytedance.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
To support block resize, this uses vduse_dev_update_config()
to update the capacity field in configuration space and inject
config interrupt on the block resize callback.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220523084611.91-8-xieyongji@bytedance.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This implements a VDUSE block backends based on
the libvduse library. We can use it to export the BDSs
for both VM and container (host) usage.
The new command-line syntax is:
$ qemu-storage-daemon \
--blockdev file,node-name=drive0,filename=test.img \
--export vduse-blk,node-name=drive0,id=vduse-export0,writable=on
After the qemu-storage-daemon started, we need to use
the "vdpa" command to attach the device to vDPA bus:
$ vdpa dev add name vduse-export0 mgmtdev vduse
Also the device must be removed via the "vdpa" command
before we stop the qemu-storage-daemon.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220523084611.91-7-xieyongji@bytedance.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Abstract the common logic of virtio-blk I/O process to a function
named virtio_blk_process_req(). It's needed for the following commit.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Message-Id: <20220523084611.91-4-xieyongji@bytedance.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Now the req->size is set to the correct value only
when handling VIRTIO_BLK_T_GET_ID request. This patch
fixes it.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Message-Id: <20220523084611.91-3-xieyongji@bytedance.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit 1b7fd72955 ("block: rename buffer_alignment to
guest_block_size") noted:
At this point, the field is set by the device emulation, but completely
ignored by the block layer.
The last time the value of buffer_alignment/guest_block_size was
actually used was before commit 339064d506 ("block: Don't use guest
sector size for qemu_blockalign()").
This value has not been used since 2013. Get rid of it.
Cc: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220518130945.2657905-1-stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Faria <afaria@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Move the various memalign-related functions out of osdep.h and into
their own header, which we include only where they are used.
While we're doing this, add some brief documentation comments.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20220226180723.1706285-10-peter.maydell@linaro.org
Allow writable exports to get BLK_PERM_RESIZE permission
from creation, in fuse_export_create().
In this way, there is no need to give the permission in
fuse_do_truncate(), which might be run in an iothread.
Permissions should be set only in the main thread, so
in any case if an iothread tries to set RESIZE, it will
be blocked.
Also assert in fuse_do_truncate that if we give the
RESIZE permission we can then restore the original ones.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220303151616.325444-7-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function is currently just a wrapper for bdrv_invalidate_cache(),
but in future will contain the code of bdrv_co_invalidate_cache() that
has to always be protected by BQL, and leave the rest in the I/O
coroutine.
Replace all bdrv_invalidate_cache() invokations with bdrv_activate().
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220209105452.1694545-4-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
When building on FreeBSD we get:
[816/6851] Compiling C object libblockdev.fa.p/block_export_fuse.c.o
../block/export/fuse.c:628:16: error: use of undeclared identifier 'FALLOC_FL_KEEP_SIZE'
if (mode & FALLOC_FL_KEEP_SIZE) {
^
../block/export/fuse.c:651:16: error: use of undeclared identifier 'FALLOC_FL_PUNCH_HOLE'
if (mode & FALLOC_FL_PUNCH_HOLE) {
^
../block/export/fuse.c:652:22: error: use of undeclared identifier 'FALLOC_FL_KEEP_SIZE'
if (!(mode & FALLOC_FL_KEEP_SIZE)) {
^
3 errors generated.
FAILED: libblockdev.fa.p/block_export_fuse.c.o
Meson indeed reported FALLOC_FL_PUNCH_HOLE is not available:
C compiler for the host machine: cc (clang 10.0.1 "FreeBSD clang version 10.0.1")
Checking for function "fallocate" : NO
Checking for function "posix_fallocate" : YES
Header <linux/falloc.h> has symbol "FALLOC_FL_PUNCH_HOLE" : NO
Header <linux/falloc.h> has symbol "FALLOC_FL_ZERO_RANGE" : NO
...
Similarly to commit 304332039 ("block/export/fuse.c: fix musl build"),
guard the code requiring FALLOC_FL_KEEP_SIZE / FALLOC_FL_PUNCH_HOLE
definitions under CONFIG_FALLOCATE_PUNCH_HOLE #ifdef'ry.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220201112655.344373-3-f4bug@amsat.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In order to safely maintain a mixture of #ifdef'ry with if-else-if
ladder, rearrange the last statement (!mode) first. Since it is
mutually exclusive with the other conditions, checking it first
doesn't make any logical difference, but allows to add #ifdef'ry
around in a more cleanly way.
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220201112655.344373-2-f4bug@amsat.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The vhost-user-blk export runs requests asynchronously in their own
coroutine. When the vhost connection goes away and we want to stop the
vhost-user server, we need to wait for these coroutines to stop before
we can unmap the shared memory. Otherwise, they would still access the
unmapped memory and crash.
This introduces a refcount to VuServer which is increased when spawning
a new request coroutine and decreased before the coroutine exits. The
memory is only unmapped when the refcount reaches zero.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20220125151435.48792-1-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Adaptive polling measures the execution time of the polling check plus
handlers called when a polled event becomes ready. Handlers can take a
significant amount of time, making it look like polling was running for
a long time when in fact the event handler was running for a long time.
For example, on Linux the io_submit(2) syscall invoked when a virtio-blk
device's virtqueue becomes ready can take 10s of microseconds. This
can exceed the default polling interval (32 microseconds) and cause
adaptive polling to stop polling.
By excluding the handler's execution time from the polling check we make
the adaptive polling calculation more accurate. As a result, the event
loop now stays in polling mode where previously it would have fallen
back to file descriptor monitoring.
The following data was collected with virtio-blk num-queues=2
event_idx=off using an IOThread. Before:
168k IOPS, IOThread syscalls:
9837.115 ( 0.020 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 16, iocbpp: 0x7fcb9f937db0) = 16
9837.158 ( 0.002 ms): IO iothread1/620155 write(fd: 103, buf: 0x556a2ef71b88, count: 8) = 8
9837.161 ( 0.001 ms): IO iothread1/620155 write(fd: 104, buf: 0x556a2ef71b88, count: 8) = 8
9837.163 ( 0.001 ms): IO iothread1/620155 ppoll(ufds: 0x7fcb90002800, nfds: 4, tsp: 0x7fcb9f1342d0, sigsetsize: 8) = 3
9837.164 ( 0.001 ms): IO iothread1/620155 read(fd: 107, buf: 0x7fcb9f939cc0, count: 512) = 8
9837.174 ( 0.001 ms): IO iothread1/620155 read(fd: 105, buf: 0x7fcb9f939cc0, count: 512) = 8
9837.176 ( 0.001 ms): IO iothread1/620155 read(fd: 106, buf: 0x7fcb9f939cc0, count: 512) = 8
9837.209 ( 0.035 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 32, iocbpp: 0x7fca7d0cebe0) = 32
174k IOPS (+3.6%), IOThread syscalls:
9809.566 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0cdd62be0) = 32
9809.625 ( 0.001 ms): IO iothread1/623061 write(fd: 103, buf: 0x5647cfba5f58, count: 8) = 8
9809.627 ( 0.002 ms): IO iothread1/623061 write(fd: 104, buf: 0x5647cfba5f58, count: 8) = 8
9809.663 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0d0388b50) = 32
Notice that ppoll(2) and eventfd read(2) syscalls are eliminated because
the IOThread stays in polling mode instead of falling back to file
descriptor monitoring.
As usual, polling is not implemented on Windows so this patch ignores
the new io_poll_read() callback in aio-win32.c.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id: 20211207132336.36627-2-stefanha@redhat.com
[Fixed up aio_set_event_notifier() calls in
tests/unit/test-fdmon-epoll.c added after this series was queued.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Include linux/falloc.h if CONFIG_FALLOCATE_ZERO_RANGE is defined to fix
50482fda98
and avoid the following build failure on musl:
../block/export/fuse.c: In function 'fuse_fallocate':
../block/export/fuse.c:643:21: error: 'FALLOC_FL_ZERO_RANGE' undeclared (first use in this function)
643 | else if (mode & FALLOC_FL_ZERO_RANGE) {
| ^~~~~~~~~~~~~~~~~~~~
Fixes:
- http://autobuild.buildroot.org/results/be24433a429fda681fb66698160132c1c99bc53b
Fixes: 50482fda98 ("block/export/fuse.c: fix musl build")
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Message-Id: <20211022095209.1319671-1-fontaine.fabrice@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Include linux/fs.h to avoid the following build failure on uclibc or
musl raised since version 6.0.0:
../block/export/fuse.c: In function 'fuse_lseek':
../block/export/fuse.c:641:19: error: 'SEEK_HOLE' undeclared (first use in this function)
641 | if (whence != SEEK_HOLE && whence != SEEK_DATA) {
| ^~~~~~~~~
../block/export/fuse.c:641:19: note: each undeclared identifier is reported only once for each function it appears in
../block/export/fuse.c:641:42: error: 'SEEK_DATA' undeclared (first use in this function); did you mean 'SEEK_SET'?
641 | if (whence != SEEK_HOLE && whence != SEEK_DATA) {
| ^~~~~~~~~
| SEEK_SET
Fixes:
- http://autobuild.buildroot.org/results/33c90ebf04997f4d3557cfa66abc9cf9a3076137
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Message-Id: <20210827220301.272887-1-fontaine.fabrice@gmail.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Fix the following build failure on musl raised since version 6.0.0 and
4ca37a96a7
because musl does not define FALLOC_FL_ZERO_RANGE:
../block/export/fuse.c: In function 'fuse_fallocate':
../block/export/fuse.c:563:23: error: 'FALLOC_FL_ZERO_RANGE' undeclared (first use in this function)
563 | } else if (mode & FALLOC_FL_ZERO_RANGE) {
| ^~~~~~~~~~~~~~~~~~~~
Fixes:
- http://autobuild.buildroot.org/results/b96e3d364fd1f8bbfb18904a742e73327d308f64
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Message-Id: <20210809095101.1101336-1-fontaine.fabrice@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
When invoking block-export-add with some iothread and
fixed-iothread=false, and changing the node's iothread fails, the error
is supposed to be ignored.
However, it is still stored in *errp, which is wrong. If a second error
occurs, the "*errp must be NULL" assertion in error_setv() fails:
qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion
`*errp == NULL' failed.
So if fixed-iothread=false, we should ignore the error by passing NULL
to bdrv_try_set_aio_context().
Fixes: f51d23c80a
("block/export: add iothread and fixed-iothread options")
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210624083825.29224-2-mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Allow changing the file mode, UID, and GID through SETATTR.
Without allow_other, UID and GID are not allowed to be changed, because
it would not make sense. Also, changing group or others' permissions
is not allowed either.
For read-only exports, +w cannot be set.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210625142317.271673-5-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In order to support changing other attributes than the file size in
fuse_setattr(), we have to give each its own independent branch. This
also applies to the only attribute we do support right now.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210625142317.271673-4-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Without the allow_other mount option, no user (not even root) but the
one who started qemu/the storage daemon can access the export. Allow
users to configure the export such that such accesses are possible.
While allow_other is probably what users want, we cannot make it an
unconditional default, because passing it is only possible (for non-root
users) if the global fuse.conf configuration file allows it. Thus, the
default is an 'auto' mode, in which we first try with allow_other, and
then fall back to without.
FuseExport.allow_other reports whether allow_other was actually used as
a mount option or not. Currently, this information is not used, but a
future patch will let this field decide whether e.g. an export's UID and
GID can be changed through chmod.
One notable thing about 'auto' mode is that libfuse may print error
messages directly to stderr, and so may fusermount (which it executes).
Our export code cannot really filter or hide them. Therefore, if 'auto'
fails its first attempt and has to fall back, fusermount will print an
error message that mounting with allow_other failed.
This behavior necessitates a change to iotest 308, namely we need to
filter out this error message (because if the first attempt at mounting
with allow_other succeeds, there will be no such message).
Furthermore, common.rc's _make_test_img should use allow-other=off for
FUSE exports, because iotests generally do not need to access images
from other users, so allow-other=on or allow-other=auto have no
advantage. OTOH, allow-other=on will not work on systems where
user_allow_other is disabled, and with allow-other=auto, we get said
error message that we would need to filter out again. Just disabling
allow-other is simplest.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210625142317.271673-3-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We do not do any permission checks in fuse_open(), so let the kernel do
them. We already let fuse_getattr() report the proper UNIX permissions,
so this should work the way we want.
This causes a change in 308's reference output, because now opening a
non-writable export with O_RDWR fails already, instead of only actually
attempting to write to it. (That is an improvement.)
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210625142317.271673-2-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The checks in vu_blk_sect_range_ok() assume VIRTIO_BLK_SECTOR_SIZE is
equal to BDRV_SECTOR_SIZE. This is true, but let's add a
QEMU_BUILD_BUG_ON() to make it explicit.
We might as well check that the request buffer size is a multiple of
VIRTIO_BLK_SECTOR_SIZE while we're at it.
Suggested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20210331142727.391465-1-stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
