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2023-01-20include/block: Untangle inclusion loopsMarkus Armbruster
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 d7e2fe4aac8. 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>
2023-01-20coroutine: Split qemu/coroutine-core.h off qemu/coroutine.hMarkus Armbruster
qemu/coroutine.h and qemu/lockable.h include each other. They need each other only in macro expansions, so we could simply drop both inclusions to break the loop, and add suitable includes to files that expand the macros. Instead, move a part of qemu/coroutine.h to new qemu/coroutine-core.h so that qemu/coroutine-core.h doesn't need qemu/lockable.h, and qemu/lockable.h only needs qemu/coroutine-core.h. Result: qemu/coroutine.h includes qemu/lockable.h includes qemu/coroutine-core.h. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20221221131435.3851212-5-armbru@redhat.com> [Semantic rebase conflict with 7c10cb38cc "accel/tcg: Add debuginfo support" resolved]
2023-01-19coroutine: Clean up superfluous inclusion of qemu/coroutine.hMarkus Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20221221131435.3851212-2-armbru@redhat.com>
2022-12-15block-backend: replace bdrv_*_above with blk_*_aboveEmanuele Giuseppe Esposito
Avoid mixing bdrv_* functions with blk_*, so create blk_* counterparts for bdrv_block_status_above and bdrv_is_allocated_above. Note that since blk_co_block_status_above only calls the g_c_w function bdrv_common_block_status_above and is marked as coroutine_fn, call directly bdrv_co_common_block_status_above() to avoid using a g_c_w. Same applies to blk_co_is_allocated_above. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-5-eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-15nbd/server.c: add coroutine_fn annotationsEmanuele Giuseppe Esposito
These functions end up calling bdrv_*() implemented as generated_co_wrapper functions. In addition, they also happen to be always called in coroutine context, meaning all callers are coroutine_fn. This means that the g_c_w function will enter the qemu_in_coroutine() case and eventually suspend (or in other words call qemu_coroutine_yield()). Therefore we can mark such functions coroutine_fn too. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-4-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-13nbd/server: Clean up abuse of BlockExportOptionsNbd member @argMarkus Armbruster
block-export-add argument @name defaults to the value of argument @node-name. nbd_export_create() implements this by copying @node_name to @name. It leaves @has_node_name false, violating the "has_node_name == !!node_name" invariant. Unclean. Falls apart when we elide @has_node_name (next commit): then QAPI frees the same value twice, once for @node_name and once @name. iotest 307 duly explodes. Goes back to commit c62d24e906 "blockdev-nbd: Boxed argument type for nbd-server-add" (v5.0.0). Got moved from qmp_nbd_server_add() to nbd_export_create() (commit 56ee86261e), then copied back (commit b6076afcab). Commit 8675cbd68b "nbd: Utilize QAPI_CLONE for type conversion" (v5.2.0) cleaned up the copy in qmp_nbd_server_add() noting Second, our assignment to arg->name is fishy: the generated QAPI code for qapi_free_NbdServerAddOptions does not visit arg->name if arg->has_name is false, but if it DID visit it, we would have introduced a double-free situation when arg is finally freed. Exactly. However, the copy in nbd_export_create() remained dirty. Clean it up. Since the value stored in member @name is not actually used outside this function, use a local variable instead of modifying the QAPI object. Signed-off-by: Markus Armbruster <armbru@redhat.com> Cc: Eric Blake <eblake@redhat.com> Cc: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Cc: qemu-block@nongnu.org Message-Id: <20221104160712.3005652-10-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
2022-07-12block: Change blk_{pread,pwrite}() param orderAlberto Faria
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>
2022-07-12block: Add a 'flags' param to blk_pread()Alberto Faria
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>
2022-06-29nbd: trace long NBD operationsDenis V. Lunev
At the moment there are 2 sources of lengthy operations if configured: * open connection, which could retry inside and * reconnect of already opened connection These operations could be quite lengthy and cumbersome to catch thus it would be quite natural to add trace points for them. This patch is based on the original downstream work made by Vladimir. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> CC: Kevin Wolf <kwolf@redhat.com> CC: Hanna Reitz <hreitz@redhat.com> CC: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
2022-05-12nbd/server: Allow MULTI_CONN for shared writable exportsEric Blake
According to the NBD spec, a server that advertises NBD_FLAG_CAN_MULTI_CONN promises that multiple client connections will not see any cache inconsistencies: when properly separated by a single flush, actions performed by one client will be visible to another client, regardless of which client did the flush. We always satisfy these conditions in qemu - even when we support multiple clients, ALL clients go through a single point of reference into the block layer, with no local caching. The effect of one client is instantly visible to the next client. Even if our backend were a network device, we argue that any multi-path caching effects that would cause inconsistencies in back-to-back actions not seeing the effect of previous actions would be a bug in that backend, and not the fault of caching in qemu. As such, it is safe to unconditionally advertise CAN_MULTI_CONN for any qemu NBD server situation that supports parallel clients. Note, however, that we don't want to advertise CAN_MULTI_CONN when we know that a second client cannot connect (for historical reasons, qemu-nbd defaults to a single connection while nbd-server-add and QMP commands default to unlimited connections; but we already have existing means to let either style of NBD server creation alter those defaults). This is visible by no longer advertising MULTI_CONN for 'qemu-nbd -r' without -e, as in the iotest nbd-qemu-allocation. The harder part of this patch is setting up an iotest to demonstrate behavior of multiple NBD clients to a single server. It might be possible with parallel qemu-io processes, but I found it easier to do in python with the help of libnbd, and help from Nir and Vladimir in writing the test. Signed-off-by: Eric Blake <eblake@redhat.com> Suggested-by: Nir Soffer <nsoffer@redhat.com> Suggested-by: Vladimir Sementsov-Ogievskiy <v.sementsov-og@mail.ru> Message-Id: <20220512004924.417153-3-eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-04-26qapi: nbd-export: allow select bitmaps by node/name pairVladimir Sementsov-Ogievskiy
Hi all! Current logic of relying on search through backing chain is not safe neither convenient. Sometimes it leads to necessity of extra bitmap copying. Also, we are going to add "snapshot-access" driver, to access some snapshot state through NBD. And this driver is not formally a filter, and of course it's not a COW format driver. So, searching through backing chain will not work. Instead of widening the workaround of bitmap searching, let's extend the interface so that user can select bitmap precisely. Note, that checking for bitmap active status is not copied to the new API, I don't see a reason for it, user should understand the risks. And anyway, bitmap from other node is unrelated to this export being read-only or read-write. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org> Message-Id: <20220314213226.362217-3-v.sementsov-og@mail.ru> [eblake: Adjust S-o-b to Vladimir's new email, with permission] Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2022-03-22Remove trailing ; after G_DEFINE_AUTO macroMarc-André Lureau
The macro doesn't need it. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2022-03-22Replace GCC_FMT_ATTR with G_GNUC_PRINTFMarc-André Lureau
One less qemu-specific macro. It also helps to make some headers/units only depend on glib, and thus moved in standalone projects eventually. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
2022-03-09Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2022-03-07' into ↵Peter Maydell
staging nbd patches for 2022-03-07 - Dan Berrange: Allow qemu-nbd to support TLS over Unix sockets - Eric Blake: Minor cleanups related to 64-bit block operations # gpg: Signature made Tue 08 Mar 2022 01:41:35 GMT # gpg: using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A # gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full] # gpg: aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full] # gpg: aka "[jpeg image of size 6874]" [full] # Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2 F3AA A7A1 6B4A 2527 436A * remotes/ericb/tags/pull-nbd-2022-03-07: qemu-io: Allow larger write zeroes under no fallback qemu-io: Utilize 64-bit status during map nbd/server: Minor cleanups tests/qemu-iotests: validate NBD TLS with UNIX sockets and PSK tests/qemu-iotests: validate NBD TLS with UNIX sockets tests/qemu-iotests: validate NBD TLS with hostname mismatch tests/qemu-iotests: convert NBD TLS test to use standard filters tests/qemu-iotests: introduce filter for qemu-nbd export list tests/qemu-iotests: expand _filter_nbd rules tests/qemu-iotests: add QEMU_IOTESTS_REGEN=1 to update reference file block/nbd: don't restrict TLS usage to IP sockets qemu-nbd: add --tls-hostname option for TLS certificate validation block/nbd: support override of hostname for TLS certificate validation block: pass desired TLS hostname through from block driver client crypto: mandate a hostname when checking x509 creds on a client Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2022-03-07nbd/server: Minor cleanupsEric Blake
Spelling fixes, grammar improvements and consistent spacing, noticed while preparing other patches in this file. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20211203231539.3900865-2-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2022-03-07block: pass desired TLS hostname through from block driver clientDaniel P. Berrangé
In commit a71d597b989fd701b923f09b3c20ac4fcaa55e81 Author: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Date: Thu Jun 10 13:08:00 2021 +0300 block/nbd: reuse nbd_co_do_establish_connection() in nbd_open() the use of the 'hostname' field from the BDRVNBDState struct was lost, and 'nbd_connect' just hardcoded it to match the IP socket address. This was a harmless bug at the time since we block use with anything other than IP sockets. Shortly though, we want to allow the caller to override the hostname used in the TLS certificate checks. This is to allow for TLS when doing port forwarding or tunneling. Thus we need to reinstate the passing along of the 'hostname'. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20220304193610.3293146-3-berrange@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2022-03-07osdep: Move memalign-related functions to their own headerPeter Maydell
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
2022-01-28nbd/server.c: Remove unused fieldNir Soffer
NBDRequestData struct has unused QSIMPLEQ_ENTRY field. It seems that this field exists since the first git commit and was never used. Signed-off-by: Nir Soffer <nsoffer@redhat.com> Message-Id: <20220111194313.581486-1-nsoffer@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Fixes: d9a73806 ("qemu-nbd: introduce NBDRequest", v1.1) Signed-off-by: Eric Blake <eblake@redhat.com>
2021-12-21nbd/client-connection: improve error message of cancelled attemptVladimir Sementsov-Ogievskiy
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2021-12-21nbd/client-connection: nbd_co_establish_connection(): return real errorVladimir Sementsov-Ogievskiy
The only caller of nbd_do_establish_connection() that uses errp is nbd_open(). The only way to cancel this call is through open_timer timeout. And for this case, user will be more interested in description of last failed connect rather than in "Connection attempt cancelled by other operation". So, let's change behavior on cancel to return previous failure error if available. Do the same for non-blocking failure case. In this case we still don't have a caller that is interested in errp. But let's be consistent. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2021-11-22nbd/server: Simplify zero and trimEric Blake
Now that the block layer supports 64-bit operations (see commit 2800637a and friends, new to v6.2), we no longer have to self-fragment requests larger than 2G, reverting the workaround added in 890cbccb08 ("nbd: Fix large trim/zero requests", v5.1.0). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20211117170230.1128262-3-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-11-22nbd/server: Don't complain on certain client disconnectsEric Blake
When a client disconnects abruptly, but did not have any pending requests (for example, when using nbdsh without calling h.shutdown), we used to output the following message: $ qemu-nbd -f raw file $ nbdsh -u 'nbd://localhost:10809' -c 'h.trim(1,0)' qemu-nbd: Disconnect client, due to: Failed to read request: Unexpected end-of-file before all bytes were read Then in commit f148ae7, we refactored nbd_receive_request() to use nbd_read_eof(); when this returns 0, we regressed into tracing uninitialized memory (if tracing is enabled) and reporting a less-specific: qemu-nbd: Disconnect client, due to: Request handling failed in intermediate state Note that with Unix sockets, we have yet another error message, unchanged by the 6.0 regression: $ qemu-nbd -k /tmp/sock -f raw file $ nbdsh -u 'nbd+unix:///?socket=/tmp/sock' -c 'h.trim(1,0)' qemu-nbd: Disconnect client, due to: Failed to send reply: Unable to write to socket: Broken pipe But in all cases, the error message goes away if the client performs a soft shutdown by using NBD_CMD_DISC, rather than a hard shutdown by abrupt disconnect: $ nbdsh -u 'nbd://localhost:10809' -c 'h.trim(1,0)' -c 'h.shutdown()' This patch fixes things to avoid uninitialized memory, and in general avoids warning about a client that does a hard shutdown when not in the middle of a packet. A client that aborts mid-request, or which does not read the full server's reply, can still result in warnings, but those are indeed much more unusual situations. CC: qemu-stable@nongnu.org Fixes: f148ae7d36 ("nbd/server: Quiesce coroutines on context switch", v6.0.0) Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [eblake: defer unrelated typo fixes to later patch] Message-Id: <20211117170230.1128262-2-eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-11-16nbd/server: Silence clang sanitizer warningEric Blake
clang's sanitizer is picky: memset(NULL, x, 0) is technically undefined behavior, even though no sane implementation of memset() deferences the NULL. Caught by the nbd-qemu-allocation iotest. The alternative to checking before each memset is to instead force an allocation of 1 element instead of g_new0(type, 0)'s behavior of returning NULL for a 0-length array. Reported-by: Peter Maydell <peter.maydell@linaro.org> Fixes: 3b1f244c59 (nbd: Allow export of multiple bitmaps for one device) Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20211115223943.626416-1-eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2021-09-29block/nbd: drop connection_coVladimir Sementsov-Ogievskiy
OK, that's a big rewrite of the logic. Pre-patch we have an always running coroutine - connection_co. It does reply receiving and reconnecting. And it leads to a lot of difficult and unobvious code around drained sections and context switch. We also abuse bs->in_flight counter which is increased for connection_co and temporary decreased in points where we want to allow drained section to begin. One of these place is in another file: in nbd_read_eof() in nbd/client.c. We also cancel reconnect and requests waiting for reconnect on drained begin which is not correct. And this patch fixes that. Let's finally drop this always running coroutine and go another way: do both reconnect and receiving in request coroutines. The detailed list of changes below (in the sequence of diff hunks). 1. receiving coroutines are woken directly from nbd_channel_error, when we change s->state 2. nbd_co_establish_connection_cancel(): we don't have drain_begin now, and in nbd_teardown_connection() all requests should already be finished (and reconnect is done from request). So nbd_co_establish_connection_cancel() is called from nbd_cancel_in_flight() (to cancel the request that is doing nbd_co_establish_connection()) and from reconnect_delay_timer_cb() (previously we didn't need it, as reconnect delay only should cancel active requests not the reconnection itself). But now reconnection itself is done in the separate thread (we now call nbd_client_connection_enable_retry() in nbd_open()), and we need to cancel the requests that wait in nbd_co_establish_connection() now). 2A. We do receive headers in request coroutine. But we also should dispatch replies for other pending requests. So, nbd_connection_entry() is turned into nbd_receive_replies(), which does reply dispatching while it receives other request headers, and returns when it receives the requested header. 3. All old staff around drained sections and context switch is dropped. In details: - we don't need to move connection_co to new aio context, as we don't have connection_co anymore - we don't have a fake "request" of connection_co (extra increasing in_flight), so don't care with it in drain_begin/end - we don't stop reconnection during drained section anymore. This means that drain_begin may wait for a long time (up to reconnect_delay). But that's an improvement and more correct behavior see below[*] 4. In nbd_teardown_connection() we don't have to wait for connection_co, as it is dropped. And cleanup for s->ioc and nbd_yank is moved here from removed connection_co. 5. In nbd_co_do_establish_connection() we now should handle NBD_CLIENT_CONNECTING_NOWAIT: if new request comes when we are in NBD_CLIENT_CONNECTING_NOWAIT, it still should call nbd_co_establish_connection() (who knows, maybe the connection was already established by another thread in the background). But we shouldn't wait: if nbd_co_establish_connection() can't return new channel immediately the request should fail (we are in NBD_CLIENT_CONNECTING_NOWAIT state). 6. nbd_reconnect_attempt() is simplified: it's now easier to wait for other requests in the caller, so here we just assert that fact. Also delay time is now initialized here: we can easily detect first attempt and start a timer. 7. nbd_co_reconnect_loop() is dropped, we don't need it. Reconnect retries are fully handle by thread (nbd/client-connection.c), delay timer we initialize in nbd_reconnect_attempt(), we don't have to bother with s->drained and friends. nbd_reconnect_attempt() now called from nbd_co_send_request(). 8. nbd_connection_entry is dropped: reconnect is now handled by nbd_co_send_request(), receiving reply is now handled by nbd_receive_replies(): all handled from request coroutines. 9. So, welcome new nbd_receive_replies() called from request coroutine, that receives reply header instead of nbd_connection_entry(). Like with sending requests, only one coroutine may receive in a moment. So we introduce receive_mutex, which is locked around nbd_receive_reply(). It also protects some related fields. Still, full audit of thread-safety in nbd driver is a separate task. New function waits for a reply with specified handle being received and works rather simple: Under mutex: - if current handle is 0, do receive by hand. If another handle received - switch to other request coroutine, release mutex and yield. Otherwise return success - if current handle == requested handle, we are done - otherwise, release mutex and yield 10: in nbd_co_send_request() we now do nbd_reconnect_attempt() if needed. Also waiting in free_sema queue we now wait for one of two conditions: - connectED, in_flight < MAX_NBD_REQUESTS (so we can start new one) - connectING, in_flight == 0, so we can call nbd_reconnect_attempt() And this logic is protected by s->send_mutex Also, on failure we don't have to care of removed s->connection_co 11. nbd_co_do_receive_one_chunk(): now instead of yield() and wait for s->connection_co we just call new nbd_receive_replies(). 12. nbd_co_receive_one_chunk(): place where s->reply.handle becomes 0, which means that handling of the whole reply is finished. Here we need to wake one of coroutines sleeping in nbd_receive_replies(). If none are sleeping - do nothing. That's another behavior change: we don't have endless recv() in the idle time. It may be considered as a drawback. If so, it may be fixed later. 13. nbd_reply_chunk_iter_receive(): don't care about removed connection_co, just ping in_flight waiters. 14. Don't create connection_co, enable retry in the connection thread (we don't have own reconnect loop anymore) 15. We now need to add a nbd_co_establish_connection_cancel() call in nbd_cancel_in_flight(), to cancel the request that is doing a connection attempt. [*], ok, now we don't cancel reconnect on drain begin. That's correct: reconnect feature leads to possibility of long-running requests (up to reconnect delay). Still, drain begin is not a reason to kill long requests. We should wait for them. This also means, that we can again reproduce a dead-lock, described in 8c517de24a8a1dcbeb54e7e12b5b0fda42a90ace. Why we are OK with it: 1. Now this is not absolutely-dead dead-lock: the vm is unfrozen after reconnect delay. Actually 8c517de24a8a1dc fixed a bug in NBD logic, that was not described in 8c517de24a8a1dc and led to forever dead-lock. The problem was that nobody woke the free_sema queue, but drain_begin can't finish until there is a request in free_sema queue. Now we have a reconnect delay timer that works well. 2. It's not a problem of the NBD driver, but of the ide code, because it does drain_begin under the global mutex; the problem doesn't reproduce when using scsi instead of ide. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210902103805.25686-5-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: grammar and comment tweaks] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-09-29nbd/client-connection: nbd_co_establish_connection(): fix non set errpVladimir Sementsov-Ogievskiy
When we don't have a connection and blocking is false, we return NULL but don't set errp. That's wrong. We have two paths for calling nbd_co_establish_connection(): 1. nbd_open() -> nbd_do_establish_connection() -> ... but that will never set blocking=false 2. nbd_reconnect_attempt() -> nbd_co_do_establish_connection() -> ... but that uses errp=NULL So, we are safe with our wrong errp policy in nbd_co_establish_connection(). Still let's fix it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210906190654.183421-2-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-09-29nbd/server: Allow LIST_META_CONTEXT without STRUCTURED_REPLYEric Blake
The NBD protocol just relaxed the requirements on NBD_OPT_LIST_META_CONTEXT: https://github.com/NetworkBlockDevice/nbd/commit/13a4e33a87 Since listing is not stateful (unlike SET_META_CONTEXT), we don't care if a client asks for meta contexts without first requesting structured replies. Well-behaved clients will still ask for structured reply first (if for no other reason than for back-compat to older servers), but that's no reason to avoid this change. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20210907173505.1499709-1-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-07-26nbd/server: Mark variable unused in nbd_negotiate_meta_queriesRichard Henderson
From clang-13: nbd/server.c:976:22: error: variable 'bitmaps' set but not used \ [-Werror,-Wunused-but-set-variable] which is incorrect; see //bugs.llvm.org/show_bug.cgi?id=3888. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-06-18nbd/client-connection: add option for non-blocking connection attemptVladimir Sementsov-Ogievskiy
We'll need a possibility of non-blocking nbd_co_establish_connection(), so that it returns immediately, and it returns success only if a connections was previously established in background. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210610100802.5888-30-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: return only one io channelVladimir Sementsov-Ogievskiy
block/nbd doesn't need underlying sioc channel anymore. So, we can update nbd/client-connection interface to return only one top-most io channel, which is more straight forward. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210610100802.5888-27-vsementsov@virtuozzo.com> [eblake: squash in Vladimir's fixes for uninit usage caught by clang] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: shutdown connection on releaseVladimir Sementsov-Ogievskiy
Now, when a thread can do negotiation and retry, it may run relatively long. We need a mechanism to stop it, when the user is not interested in a result any more. So, on nbd_client_connection_release() let's shutdown the socket, and do not retry connection if thread is detached. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210610100802.5888-22-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: implement connection retryVladimir Sementsov-Ogievskiy
Add an option for a thread to retry connecting until it succeeds. We'll use nbd/client-connection both for reconnect and for initial connection in nbd_open(), so we need a possibility to use same NBDClientConnection instance to connect once in nbd_open() and then use retry semantics for reconnect. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210610100802.5888-21-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: grammar tweak] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: add possibility of negotiationVladimir Sementsov-Ogievskiy
Add arguments and logic to support nbd negotiation in the same thread after successful connection. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210610100802.5888-20-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: use QEMU_LOCK_GUARDVladimir Sementsov-Ogievskiy
We don't update connect_thread_func() to use QEMU_LOCK_GUARD, as it will get more complex critical sections logic in further commit, where QEMU_LOCK_GUARD doesn't help. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210610100802.5888-19-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd: move connection code from block/nbd to nbd/client-connectionVladimir Sementsov-Ogievskiy
We now have bs-independent connection API, which consists of four functions: nbd_client_connection_new() nbd_client_connection_release() nbd_co_establish_connection() nbd_co_establish_connection_cancel() Move them to a separate file together with NBDClientConnection structure which becomes private to the new API. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210610100802.5888-18-vsementsov@virtuozzo.com> [eblake: comment tweaks] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-02Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into stagingPeter Maydell
Block layer patches - NBD server: Fix crashes related to switching between AioContexts - file-posix: Workaround for discard/write_zeroes on buggy filesystems - Follow-up fixes for the reopen vs. permission changes - quorum: Fix error handling for flush - block-copy: Refactor copy_range handling - docs: Describe how to use 'null-co' block driver # gpg: Signature made Wed 02 Jun 2021 14:44:15 BST # gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6 # gpg: issuer "kwolf@redhat.com" # gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full] # Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6 * remotes/kevin/tags/for-upstream: docs/secure-coding-practices: Describe how to use 'null-co' block driver block-copy: refactor copy_range handling block-copy: fix block_copy_task_entry() progress update nbd/server: Use drained block ops to quiesce the server block-backend: add drained_poll block: improve permission conflict error message block: simplify bdrv_child_user_desc() block/vvfat: inherit child_vvfat_qcow from child_of_bds block: improve bdrv_child_get_parent_desc() block-backend: improve blk_root_get_parent_desc() block: document child argument of bdrv_attach_child_common() block/file-posix: Try other fallbacks after invalid FALLOC_FL_ZERO_RANGE block/file-posix: Fix problem with fallocate(PUNCH_HOLE) on GPFS block: drop BlockBackendRootState::read_only block: drop BlockDriverState::read_only block: consistently use bdrv_is_read_only() block/vvfat: fix vvfat_child_perm crash block/vvfat: child_vvfat_qcow: add .get_parent_aio_context, fix crash qemu-io-cmds: assert that we don't have .perm requested in no-blk case block/quorum: Provide .bdrv_co_flush instead of .bdrv_co_flush_to_disk Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-06-02nbd/server: Use drained block ops to quiesce the serverSergio Lopez
Before switching between AioContexts we need to make sure that we're fully quiesced ("nb_requests == 0" for every client) when entering the drained section. To do this, we set "quiescing = true" for every client on ".drained_begin" to prevent new coroutines from being created, and check if "nb_requests == 0" on ".drained_poll". Finally, once we're exiting the drained section, on ".drained_end" we set "quiescing = false" and call "nbd_client_receive_next_request()" to resume the processing of new requests. With these changes, "blk_aio_attach()" and "blk_aio_detach()" can be reverted to be as simple as they were before f148ae7d36. RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1960137 Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Sergio Lopez <slp@redhat.com> Message-Id: <20210602060552.17433-3-slp@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-06-02docs: fix references to docs/devel/tracing.rstStefano Garzarella
Commit e50caf4a5c ("tracing: convert documentation to rST") converted docs/devel/tracing.txt to docs/devel/tracing.rst. We still have several references to the old file, so let's fix them with the following command: sed -i s/tracing.txt/tracing.rst/ $(git grep -l docs/devel/tracing.txt) Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20210517151702.109066-2-sgarzare@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2021-03-08nbd: server: Report holes for raw imagesNir Soffer
When querying image extents for raw image, qemu-nbd reports holes as zero: $ qemu-nbd -t -r -f raw empty-6g.raw $ qemu-img map --output json nbd://localhost [{ "start": 0, "length": 6442450944, "depth": 0, "zero": true, "data": true, "offset": 0}] $ qemu-img map --output json empty-6g.raw [{ "start": 0, "length": 6442450944, "depth": 0, "zero": true, "data": false, "offset": 0}] Turns out that qemu-img map reports a hole based on BDRV_BLOCK_DATA, but nbd server reports a hole based on BDRV_BLOCK_ALLOCATED. The NBD protocol says: NBD_STATE_HOLE (bit 0): if set, the block represents a hole (and future writes to that area may cause fragmentation or encounter an NBD_ENOSPC error); if clear, the block is allocated or the server could not otherwise determine its status. qemu-img manual says: whether the sectors contain actual data or not (boolean field data; if false, the sectors are either unallocated or stored as optimized all-zero clusters); To me, data=false looks compatible with NBD_STATE_HOLE. From user point of view, getting same results from qemu-nbd and qemu-img is more important than being more correct about allocation status. Changing nbd server to report holes using BDRV_BLOCK_DATA makes qemu-nbd results compatible with qemu-img map: $ qemu-img map --output json nbd://localhost [{ "start": 0, "length": 6442450944, "depth": 0, "zero": true, "data": false, "offset": 0}] Signed-off-by: Nir Soffer <nsoffer@redhat.com> Message-Id: <20210219160752.1826830-1-nsoffer@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-01-20nbd/server: Quiesce coroutines on context switchSergio Lopez
When switching between AIO contexts we need to me make sure that both recv_coroutine and send_coroutine are not scheduled to run. Otherwise, QEMU may crash while attaching the new context with an error like this one: aio_co_schedule: Co-routine was already scheduled in 'aio_co_schedule' To achieve this we need a local implementation of 'qio_channel_readv_all_eof' named 'nbd_read_eof' (a trick already done by 'nbd/client.c') that allows us to interrupt the operation and to know when recv_coroutine is yielding. With this in place, we delegate detaching the AIO context to the owning context with a BH ('nbd_aio_detach_bh') scheduled using 'aio_wait_bh_oneshot'. This BH signals that we need to quiesce the channel by setting 'client->quiescing' to 'true', and either waits for the coroutine to finish using AIO_WAIT_WHILE or, if it's yielding in 'nbd_read_eof', actively enters the coroutine to interrupt it. RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1900326 Signed-off-by: Sergio Lopez <slp@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20201214170519.223781-4-slp@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-11-17Merge remote-tracking branch ↵Peter Maydell
'remotes/huth-gitlab/tags/pull-request-2020-11-17' into staging * Fixes for compiling on Haiku, and add Haiku VM for compile-testing * Update NetBSD VM to version 9.1 * Misc fixes (e.g. categorize some devices) # gpg: Signature made Tue 17 Nov 2020 09:20:31 GMT # gpg: using RSA key 27B88847EEE0250118F3EAB92ED9D774FE702DB5 # gpg: issuer "thuth@redhat.com" # gpg: Good signature from "Thomas Huth <th.huth@gmx.de>" [full] # gpg: aka "Thomas Huth <thuth@redhat.com>" [full] # gpg: aka "Thomas Huth <huth@tuxfamily.org>" [full] # gpg: aka "Thomas Huth <th.huth@posteo.de>" [unknown] # Primary key fingerprint: 27B8 8847 EEE0 2501 18F3 EAB9 2ED9 D774 FE70 2DB5 * remotes/huth-gitlab/tags/pull-request-2020-11-17: max111x: put it into the 'misc' category nand: put it into the 'storage' category ads7846: put it into the 'input' category ssd0323: put it into the 'display' category gitlab-ci: Use $CI_REGISTRY instead of hard-coding registry.gitlab.com target/microblaze: Fix possible array out of bounds in mmu_write() tests/vm: update NetBSD to 9.1 tests/vm: Add Haiku test based on their vagrant images configure: Add a proper check for sys/ioccom.h and use it in tpm_ioctl.h configure: Do not build pc-bios/optionrom on Haiku configure: Fix the _BSD_SOURCE define for the Haiku build qemu/bswap: Remove unused qemu_bswap_len() Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-11-17configure: Add a proper check for sys/ioccom.h and use it in tpm_ioctl.hThomas Huth
On Solaris and Haiku, the _IO() macros are defined in <sys/ioccom.h>. Add a proper check for this header to our build system, and make sure to include the header in tpm_ioctl.h to fix a build failure on Solaris and Haiku. Message-Id: <20201115152317.42752-1-thuth@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2020-11-16nbd: Silence Coverity false positiveEric Blake
Coverity noticed (CID 1436125) that we check the return value of nbd_extent_array_add in most places, but not at the end of bitmap_to_extents(). The return value exists to break loops before a future iteration, so there is nothing to check if we are already done iterating. Adding a cast to void, plus a comment why, pacifies Coverity. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20201111163510.713855-1-eblake@redhat.com> [eblake: Prefer cast to void over odd && usage] Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2020-10-30nbd: Add 'qemu-nbd -A' to expose allocation depthEric Blake
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>
2020-10-30nbd: Add new qemu:allocation-depth metadata contextEric Blake
'qemu-img map' provides a way to determine which extents of an image come from the top layer vs. inherited from a backing chain. This is useful information worth exposing over NBD. There is a proposal to add a QMP command block-dirty-bitmap-populate which can create a dirty bitmap that reflects allocation information, at which point the qemu:dirty-bitmap:NAME metadata context can expose that information via the creation of a temporary bitmap, but we can shorten the effort by adding a new qemu:allocation-depth metadata context that does the same thing without an intermediate bitmap (this patch does not eliminate the need for that proposal, as it will have other uses as well). While documenting things, remember that although the NBD protocol has NBD_OPT_SET_META_CONTEXT, the rest of its documentation refers to 'metadata context', which is a more apt description of what is actually being used by NBD_CMD_BLOCK_STATUS: the user is requesting metadata by passing one or more context names. So I also touched up some existing wording to prefer the term 'metadata context' where it makes sense. Note that this patch does not actually enable any way to request a server to enable this context; that will come in the next patch. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20201027050556.269064-10-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2020-10-30nbd: Allow export of multiple bitmaps for one deviceEric Blake
With this, 'qemu-nbd -B b0 -B b1 -f qcow2 img.qcow2' can let you sniff out multiple bitmaps from one server. qemu-img as client can still only read one bitmap per client connection, but other NBD clients (hello libnbd) can now read multiple bitmaps in a single pass. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201027050556.269064-8-eblake@redhat.com>
2020-10-30nbd: Refactor counting of metadata contextsEric Blake
Rather than open-code the count of negotiated contexts at several sites, embed it directly into the struct. This will make it easier for upcoming commits to support even more simultaneous contexts. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20201027050556.269064-7-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2020-10-30nbd: Simplify qemu bitmap context nameEric Blake
Each dirty bitmap already knows its name; by reducing the scope of the places where we construct "qemu:dirty-bitmap:NAME" strings, tracking the name is more localized, and there are fewer per-export fields to worry about. This in turn will make it easier for an upcoming patch to export more than one bitmap at once. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201027050556.269064-6-eblake@redhat.com>
2020-10-30nbd: Update qapi to support exporting multiple bitmapsEric Blake
Since 'block-export-add' is new to 5.2, we can still tweak the interface; there, allowing 'bitmaps':['str'] is nicer than 'bitmap':'str'. This wires up the qapi and qemu-nbd changes to permit passing multiple bitmaps as distinct metadata contexts that the NBD client may request, but the actual support for more than one will require a further patch to the server. Note that there are no changes made to the existing deprecated 'nbd-server-add' command; this required splitting the QAPI type BlockExportOptionsNbd, which fortunately does not affect QMP introspection. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20201027050556.269064-5-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-10-23block/export: add iothread and fixed-iothread optionsStefan Hajnoczi
Make it possible to specify the iothread where the export will run. By default the block node can be moved to other AioContexts later and the export will follow. The fixed-iothread option forces strict behavior that prevents changing AioContext while the export is active. See the QAPI docs for details. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20200929125516.186715-5-stefanha@redhat.com [Fix stray '#' character in block-export.json and add missing "(since: 5.2)" as suggested by Eric Blake. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-10-23block: move block exports to libblockdevStefan Hajnoczi
Block exports are used by softmmu, qemu-storage-daemon, and qemu-nbd. They are not used by other programs and are not otherwise needed in libblock. Undo the recent move of blockdev-nbd.c from blockdev_ss into block_ss. Since bdrv_close_all() (libblock) calls blk_exp_close_all() (libblockdev) a stub function is required.. Make qemu-nbd.c use signal handling utility functions instead of duplicating the code. This helps because os-posix.c is in libblockdev and it depends on a qemu_system_killed() symbol that qemu-nbd.c lacks. Once we use the signal handling utility functions we also end up providing the necessary symbol. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20200929125516.186715-4-stefanha@redhat.com [Fixed s/ndb/nbd/ typo in commit description as suggested by Eric Blake --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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