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2024-08-08nbd/server: Plumb in new args to nbd_client_add()Eric Blake
Upcoming patches to fix a CVE need to track an opaque pointer passed in by the owner of a client object, as well as request for a time limit on how fast negotiation must complete. Prepare for that by changing the signature of nbd_client_new() and adding an accessor to get at the opaque pointer, although for now the two servers (qemu-nbd.c and blockdev-nbd.c) do not change behavior even though they pass in a new default timeout value. Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Eric Blake <eblake@redhat.com> Message-ID: <20240807174943.771624-11-eblake@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> [eblake: s/LIMIT/MAX_SECS/ as suggested by Dan] Signed-off-by: Eric Blake <eblake@redhat.com>
2024-08-08nbd: Minor style and typo fixesEric Blake
Touch up a comment with the wrong type name, and an over-long line, both noticed while working on upcoming patches. Signed-off-by: Eric Blake <eblake@redhat.com> Message-ID: <20240807174943.771624-10-eblake@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-02-13qemu-nbd: mention --tls-hostname option in qemu-nbd --helpMichael Tokarev
This option was not documented. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1240 Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2023-12-21block: remove AioContext lockingStefan Hajnoczi
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>
2023-10-05nbd/server: Add FLAG_PAYLOAD support to CMD_BLOCK_STATUSEric Blake
Allow a client to request a subset of negotiated meta contexts. For example, a client may ask to use a single connection to learn about both block status and dirty bitmaps, but where the dirty bitmap queries only need to be performed on a subset of the disk; forcing the server to compute that information on block status queries in the rest of the disk is wasted effort (both at the server, and on the amount of traffic sent over the wire to be parsed and ignored by the client). Qemu as an NBD client never requests to use more than one meta context, so it has no need to use block status payloads. Testing this instead requires support from libnbd, which CAN access multiple meta contexts in parallel from a single NBD connection; an interop test submitted to the libnbd project at the same time as this patch demonstrates the feature working, as well as testing some corner cases (for example, when the payload length is longer than the export length), although other corner cases (like passing the same id duplicated) requires a protocol fuzzer because libnbd is not wired up to break the protocol that badly. This also includes tweaks to 'qemu-nbd --list' to show when a server is advertising the capability, and to the testsuite to reflect the addition to that output. Of note: qemu will always advertise the new feature bit during NBD_OPT_INFO if extended headers have alreay been negotiated (regardless of whether any NBD_OPT_SET_META_CONTEXT negotiation has occurred); but for NBD_OPT_GO, qemu only advertises the feature if block status is also enabled (that is, if the client does not negotiate any contexts, then NBD_CMD_BLOCK_STATUS cannot be used, so the feature is not advertised). Signed-off-by: Eric Blake <eblake@redhat.com> Message-ID: <20230925192229.3186470-26-eblake@redhat.com> [eblake: fix logic to reject unnegotiated contexts] Signed-off-by: Eric Blake <eblake@redhat.com>
2023-10-05nbd/client: Request extended headers during negotiationEric Blake
All the pieces are in place for a client to finally request extended headers. Note that we must not request extended headers when qemu-nbd is used to connect to the kernel module (as nbd.ko does not expect them, but expects us to do the negotiation in userspace before handing the socket over to the kernel), but there is no harm in all other clients requesting them. Extended headers are not essential to the information collected during 'qemu-nbd --list', but probing for it gives us one more piece of information in that output. Update the iotests affected by the new line of output. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230925192229.3186470-23-eblake@redhat.com>
2023-09-29qemu-nbd: changes towards enabling -Wshadow=localEric Blake
Address all compiler complaints from -Wshadow in qemu-nbd. Several instances of 'int ret' became shadows when commit 4fbec260 added 'ret' at a higher scope in main. More interesting was the 'void *ret' capturing the result of a pthread; where we were conceptually doing '(void*)(intptr_t)EXIT_FAILURE != NULL' which just feels wrong (even though it happens to compile correctly), so it was worth a better cleanup. Signed-off-by: Eric Blake <eblake@redhat.com> Message-ID: <20230922205019.2755352-2-eblake@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2023-09-22nbd: Replace bool structured_reply with mode enumEric Blake
The upcoming patches for 64-bit extensions requires various points in the protocol to make decisions based on what was negotiated. While we could easily add a 'bool extended_headers' alongside the existing 'bool structured_reply', this does not scale well if more modes are added in the future. Better is to expose the mode enum added in the recent commit bfe04d0a7d out to a wider use in the code base. Where the code previously checked for structured_reply being set or clear, it now prefers checking for an inequality; this works because the nodes are in a continuum of increasing abilities, and allows us to touch fewer places if we ever insert other modes in the middle of the enum. There should be no semantic change in this patch. Signed-off-by: Eric Blake <eblake@redhat.com> Message-ID: <20230829175826.377251-20-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
2023-09-08qemu-nbd: Restore "qemu-nbd -v --fork" outputDenis V. Lunev
Closing stderr earlier is good for daemonized qemu-nbd under ssh earlier, but breaks the case where -v is being used to track what is happening in the server, as in iotest 233. When we know we are verbose, we should preserve original stderr and restore it once the setup stage is done. This commit restores the original behavior with -v option. In this case original output inside the test is kept intact. Reported-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> CC: Hanna Reitz <hreitz@redhat.com> CC: Mike Maslenkin <mike.maslenkin@gmail.com> Fixes: 5c56dd27a2 ("qemu-nbd: fix regression with qemu-nbd --fork run over ssh") Message-ID: <20230906093210.339585-7-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Eric Blake <eblake@redhat.com> [eblake: fix build by avoiding stderr as struct member name] Signed-off-by: Eric Blake <eblake@redhat.com>
2023-09-07qemu-nbd: invent nbd_client_release_pipe() helperDenis V. Lunev
Move the code from main() and nbd_client_thread() into the specific helper. This code is going to be grown. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230906093210.339585-6-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2023-09-07qemu-nbd: put saddr into into struct NbdClientOptsDenis V. Lunev
We pass other parameters into nbd_client_thread() in this way. This patch makes the code more consistent. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230906093210.339585-5-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2023-09-07qemu-nbd: move srcpath into struct NbdClientOptsDenis V. Lunev
We pass other parameters into nbd_client_thread() in this way. This patch makes the code more consistent. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230906093210.339585-4-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: Note that this also cleans up a -Wshadow issue, first introduced in e5b815b0] Signed-off-by: Eric Blake <eblake@redhat.com>
2023-09-07qemu-nbd: define struct NbdClientOpts when HAVE_NBD_DEVICE is not definedDenis V. Lunev
This patch also drops definition of some locals in main() to avoid useless data copy. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230906093210.339585-3-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2023-09-07qemu-nbd: improve error message for dup2 errorDenis V. Lunev
This error happens if we are not able to close the pipe to the parent (to trace errors in the child process) and assign stderr to /dev/null as required by the daemonizing convention. Signed-off-by: Denis V. Lunev <den@openvz.org> Suggested-by: Eric Blake <eblake@redhat.com> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230906093210.339585-2-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: commit message grammar] Signed-off-by: Eric Blake <eblake@redhat.com>
2023-09-07nbd: drop unused nbd_receive_negotiate() aio_context argumentStefan Hajnoczi
aio_context is always NULL, so drop it. Suggested-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-ID: <20230830224802.493686-2-stefanha@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2023-07-27qemu-nbd: regression with arguments passing into nbd_client_thread()Denis V. Lunev
Unfortunately commit 03b67621445d601c9cdc7dfe25812e9f19b81488 Author: Denis V. Lunev <den@openvz.org> Date: Mon Jul 17 16:55:40 2023 +0200 qemu-nbd: pass structure into nbd_client_thread instead of plain char* has introduced a regression. struct NbdClientOpts resides on stack inside 'if' block. This specifically means that this stack space could be reused once the execution will leave that block of the code. This means that parameters passed into nbd_client_thread could be overwritten at any moment. The patch moves the data to the namespace of main() function effectively preserving it for the whole process lifetime. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> CC: <qemu-stable@nongnu.org> Reviewed-by: Eric Blake <eblake@redhat.com> Message-ID: <20230727105828.324314-1-den@openvz.org> Signed-off-by: Eric Blake <eblake@redhat.com>
2023-07-19qemu-nbd: make verbose bool and local variable in main()Denis V. Lunev
Pass 'verbose' to nbd_client_thread() inside NbdClientOpts which looks a little bit cleaner and make it bool as it is used as bool actually. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230717202520.236999-1-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2023-07-19qemu-nbd: handle dup2() error when qemu-nbd finished setup processDenis V. Lunev
Fail on error, we are in trouble. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230717145544.194786-6-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: avoid intermediate variable] Signed-off-by: Eric Blake <eblake@redhat.com>
2023-07-19qemu-nbd: properly report error on error in dup2() after qemu_daemon()Denis V. Lunev
We are trying to temporarily redirect stderr of daemonized process to a pipe to report a error and get failed. In that case we could not use error_report() helper, but should write the message directly into the problematic pipe. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230717145544.194786-4-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: rearrange patch series, fix typo] Signed-off-by: Eric Blake <eblake@redhat.com>
2023-07-19qemu-nbd: properly report error if qemu_daemon() is failedDenis V. Lunev
errno has been overwritten by dup2() just below qemu_daemon() and thus improperly returned to the caller. Fix accordingly. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230717145544.194786-5-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: reorder patch series] Signed-off-by: Eric Blake <eblake@redhat.com>
2023-07-19qemu-nbd: fix regression with qemu-nbd --fork run over sshDenis V. Lunev
Commit e6df58a5578fee7a50bbf36f4a50a2781cff855d Author: Hanna Reitz <hreitz@redhat.com> Date: Wed May 8 23:18:18 2019 +0200 qemu-nbd: Do not close stderr has introduced an interesting regression. Original behavior of ssh somehost qemu-nbd /home/den/tmp/file -f raw --fork was the following: * qemu-nbd was started as a daemon * the command execution is done and ssh exited with success The patch has changed this behavior and 'ssh' command now hangs forever. According to the normal specification of the daemon() call, we should endup with STDERR pointing to /dev/null. That should be done at the very end of the successful startup sequence when the pipe to the bootstrap process (used for diagnostics) is no longer needed. This could be achived in the same way as done for 'qemu-nbd -c' case. That was commit 0eaf453e, also fixing up e6df58a5. STDOUT copying to STDERR does the trick. This also leads to proper 'ssh' connection closing which fixes my original problem. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> CC: Hanna Reitz <hreitz@redhat.com> CC: <qemu-stable@nongnu.org> Message-ID: <20230717145544.194786-3-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2023-07-19qemu-nbd: pass structure into nbd_client_thread instead of plain char*Denis V. Lunev
We are going to pass additional flag inside next patch. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> CC: <qemu-stable@nongnu.org> Message-ID: <20230717145544.194786-2-den@openvz.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2023-05-30block: Take main AioContext lock when calling bdrv_open()Kevin Wolf
The function documentation already says that all callers must hold the main AioContext lock, but not all of them do. This can cause assertion failures when functions called by bdrv_open() try to drop the lock. Fix a few more callers to take the lock before calling bdrv_open(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230525124713.401149-4-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-14qapi block: Elide redundant has_FOO in generated CMarkus Armbruster
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]
2022-05-12qemu-nbd: Pass max connections to blockdev layerEric Blake
The next patch wants to adjust whether the NBD server code advertises MULTI_CONN based on whether it is known if the server limits to exactly one client. For a server started by QMP, this information is obtained through nbd_server_start (which can support more than one export); but for qemu-nbd (which supports exactly one export), it is controlled only by the command-line option -e/--shared. Since we already have a hook function used by qemu-nbd, it's easiest to just alter its signature to fit our needs. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20220512004924.417153-2-eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-05-03Replace qemu_pipe() with g_unix_open_pipe()Marc-André Lureau
GLib g_unix_open_pipe() is essentially like qemu_pipe(), available since 2.30. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
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>
2022-04-21include: rename qemu-common.h qemu/help-texts.hMarc-André Lureau
Suggested-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Warner Losh <imp@bsdimp.com> Message-Id: <20220420132624.2439741-7-marcandre.lureau@redhat.com>
2022-04-20util/log: Pass Error pointer to qemu_set_logRichard Henderson
Do not force exit within qemu_set_log; return bool and pass an Error value back up the stack as per usual. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20220417183019.755276-5-richard.henderson@linaro.org>
2022-03-07block/nbd: don't restrict TLS usage to IP socketsDaniel P. Berrangé
The TLS usage for NBD was restricted to IP sockets because validating x509 certificates requires knowledge of the hostname that the client is connecting to. TLS does not have to use x509 certificates though, as PSK (pre-shared keys) provide an alternative credential option. These have no requirement for a hostname and can thus be trivially used for UNIX sockets. Furthermore, with the ability to overide the default hostname for TLS validation in the previous patch, it is now also valid to want to use x509 certificates with FD passing and UNIX sockets. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20220304193610.3293146-6-berrange@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2022-03-07qemu-nbd: add --tls-hostname option for TLS certificate validationDaniel P. Berrangé
When using the --list option, qemu-nbd acts as an NBD client rather than a server. As such when using TLS, it has a need to validate the server certificate. This adds a --tls-hostname option which can be used to override the default hostname used for certificate validation. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20220304193610.3293146-5-berrange@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-11-16nbd/server: Add --selinux-label optionRichard W.M. Jones
Under SELinux, Unix domain sockets have two labels. One is on the disk and can be set with commands such as chcon(1). There is a different label stored in memory (called the process label). This can only be set by the process creating the socket. When using SELinux + SVirt and wanting qemu to be able to connect to a qemu-nbd instance, you must set both labels correctly first. For qemu-nbd the options to set the second label are awkward. You can create the socket in a wrapper program and then exec into qemu-nbd. Or you could try something with LD_PRELOAD. This commit adds the ability to set the label straightforwardly on the command line, via the new --selinux-label flag. (The name of the flag is the same as the equivalent nbdkit option.) A worked example showing how to use the new option can be found in this bug: https://bugzilla.redhat.com/show_bug.cgi?id=1984938 Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1984938 Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> [eblake: rebase to configure changes, reject --selinux-label if it is not compiled in or not used on a Unix socket] Note that we may relax some of these restrictions at a later date, such as making it possible to label a TCP socket, although it may be smarter to do so as a generic QMP action rather than more one-off command lines in qemu-nbd. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20211115202944.615966-1-eblake@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com> [eblake: adjust meson output as suggested by thuth] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-09-29qemu-nbd: Change default cache mode to writebackNir Soffer
Both qemu and qemu-img use writeback cache mode by default, which is already documented in qemu(1). qemu-nbd uses writethrough cache mode by default, and the default cache mode is not documented. According to the qemu-nbd(8): --cache=CACHE The cache mode to be used with the file. See the documentation of the emulator's -drive cache=... option for allowed values. qemu(1) says: The default mode is cache=writeback. So users have no reason to assume that qemu-nbd is using writethough cache mode. The only hint is the painfully slow writing when using the defaults. Looking in git history, it seems that qemu used writethrough in the past to support broken guests that did not flush data properly, or could not flush due to limitations in qemu. But qemu-nbd clients can use NBD_CMD_FLUSH to flush data, so using writethrough does not help anyone. Change the default cache mode to writback, and document the default and available values properly in the online help and manual. With this change converting image via qemu-nbd is 3.5 times faster. $ qemu-img create dst.img 50g $ qemu-nbd -t -f raw -k /tmp/nbd.sock dst.img Before this change: $ hyperfine -r3 "./qemu-img convert -p -f raw -O raw -T none -W fedora34.img nbd+unix:///?socket=/tmp/nbd.sock" Benchmark #1: ./qemu-img convert -p -f raw -O raw -T none -W fedora34.img nbd+unix:///?socket=/tmp/nbd.sock Time (mean ± σ): 83.639 s ± 5.970 s [User: 2.733 s, System: 6.112 s] Range (min … max): 76.749 s … 87.245 s 3 runs After this change: $ hyperfine -r3 "./qemu-img convert -p -f raw -O raw -T none -W fedora34.img nbd+unix:///?socket=/tmp/nbd.sock" Benchmark #1: ./qemu-img convert -p -f raw -O raw -T none -W fedora34.img nbd+unix:///?socket=/tmp/nbd.sock Time (mean ± σ): 23.522 s ± 0.433 s [User: 2.083 s, System: 5.475 s] Range (min … max): 23.234 s … 24.019 s 3 runs Users can avoid the issue by using --cache=writeback[1] but the defaults should give good performance for the common use case. [1] https://bugzilla.redhat.com/1990656 Signed-off-by: Nir Soffer <nsoffer@redhat.com> Message-Id: <20210813205519.50518-1-nsoffer@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake <eblake@redhat.com>
2021-08-26error: Use error_fatal to simplify obvious fatal errors (again)Markus Armbruster
We did this with scripts/coccinelle/use-error_fatal.cocci before, in commit 50beeb68094 and 007b06578ab. This commit cleans up rarer variations that don't seem worth matching with Coccinelle. Cc: Thomas Huth <thuth@redhat.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Peter Xu <peterx@redhat.com> Cc: Juan Quintela <quintela@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Marc-André Lureau <marcandre.lureau@redhat.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20210720125408.387910-2-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2021-06-29qemu-nbd: Use qcrypto_tls_creds_check_endpoint()Philippe Mathieu-Daudé
Avoid accessing QCryptoTLSCreds internals by using the qcrypto_tls_creds_check_endpoint() helper. Tested-by: Akihiko Odaki <akihiko.odaki@gmail.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2021-03-19qemu-nbd: Use user_creatable_process_cmdline() for --objectKevin Wolf
This switches qemu-nbd from a QemuOpts-based parser for --object to user_creatable_process_cmdline() which uses a keyval parser and enforces the QAPI schema. Apart from being a cleanup, this makes non-scalar properties accessible. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2021-02-12qemu-nbd: Permit --shared=0 for unlimited clientsEric Blake
This gives us better feature parity with QMP nbd-server-start, where max-connections defaults to 0 for unlimited. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20210209152759.209074-3-eblake@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2021-02-12qemu-nbd: Use SOMAXCONN for socket listen() backlogEric Blake
Our default of a backlog of 1 connection is rather puny; it gets in the way when we are explicitly allowing multiple clients (such as qemu-nbd -e N [--shared], or nbd-server-start with its default "max-connections":0 for unlimited), but is even a problem when we stick to qemu-nbd's default of only 1 active client but use -t [--persistent] where a second client can start using the server once the first finishes. While the effects are less noticeable on TCP sockets (since the client can poll() to learn when the server is ready again), it is definitely observable on Unix sockets, where on Linux, a client will fail with EAGAIN and no recourse but to sleep an arbitrary amount of time before retrying if the server backlog is already full. Since QMP nbd-server-start is always persistent, it now always requests a backlog of SOMAXCONN; meanwhile, qemu-nbd will request SOMAXCONN if persistent, otherwise its backlog should be based on the expected number of clients. See https://bugzilla.redhat.com/1925045 for a demonstration of where our low backlog prevents libnbd from connecting as many parallel clients as it wants. Reported-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> CC: qemu-stable@nongnu.org Message-Id: <20210209152759.209074-2-eblake@redhat.com> Tested-by: Richard W.M. Jones <rjones@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-02-02block: move blk_exp_close_all() to qemu_cleanup()Sergio Lopez
Move blk_exp_close_all() from bdrv_close() to qemu_cleanup(), before bdrv_drain_all_begin(). Export drivers may have coroutines yielding at some point in the block layer, so we need to shut them down before draining the block layer, as otherwise they may get stuck blk_wait_while_drained(). RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1900505 Signed-off-by: Sergio Lopez <slp@redhat.com> Message-Id: <20210201125032.44713-3-slp@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-01-20qemu-nbd: Fix a memleak in nbd_client_thread()Alex Chen
When the qio_channel_socket_connect_sync() fails we should goto 'out_socket' label to free the 'sioc' instead of goto 'out' label. In addition, there's a lot of redundant code in the successful branch and the error branch, optimize it. Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Alex Chen <alex.chen@huawei.com> Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201208134944.27962-1-alex.chen@huawei.com>
2021-01-20qemu-nbd: Fix a memleak in qemu_nbd_client_list()Alex Chen
When the qio_channel_socket_connect_sync() fails we should goto 'out' label to free the 'sioc' instead of return. Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Alex Chen <alex.chen@huawei.com> Message-Id: <20201130123651.17543-1-alex.chen@huawei.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-11-11trace: remove argument from trace_init_filePaolo Bonzini
It is not needed, all the callers are just saving what was retrieved from -trace and trace_init_file can retrieve it on its own. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20201102115841.4017692-1-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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: 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: 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>
2020-10-09qemu-nbd: Honor SIGINT and SIGHUPEric Blake
Honoring just SIGTERM on Linux is too weak; we also want to handle other common signals, and do so even on BSD. Why? Because at least 'qemu-nbd -B bitmap' needs a chance to clean up the in-use bit on bitmaps when the server is shut down via a signal. See also: http://bugzilla.redhat.com/1883608 Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200930121105.667049-2-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [eblake: apply comment tweak suggested by Vladimir; fix ifdef around termsig_handler] Signed-off-by: Eric Blake <eblake@redhat.com>
2020-10-02block/export: Move writable to BlockExportOptionsKevin Wolf
The 'writable' option is a basic option that will probably be applicable to most if not all export types that we will implement. Move it from NBD to the generic BlockExport layer. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-26-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Add 'id' option to block-export-addKevin Wolf
We'll need an id to identify block exports in monitor commands. This adds one. Note that this is different from the 'name' option in the NBD server, which is the externally visible export name. While block export ids need to be unique in the whole process, export names must be unique only for the same server. Different export types or (potentially in the future) multiple NBD servers can have the same export name externally, but still need different block export ids internally. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-19-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Add blk_exp_close_all(_type)Kevin Wolf
This adds a function to shut down all block exports, and another one to shut down the block exports of a single type. The latter is used for now when stopping the NBD server. As soon as we implement support for multiple NBD servers, we'll need a per-server list of exports and it will be replaced by a function using that. As a side effect, the BlockExport layer has a list tracking all existing exports now. closed_exports loses its only user and can go away. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-18-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Add node-name to BlockExportOptionsKevin Wolf
Every block export needs a block node to export, so add a 'node-name' option to BlockExportOptions and remove the replaced option 'device' from BlockExportOptionsNbd. To maintain compatibility in nbd-server-add, BlockExportOptionsNbd needs to be wrapped by a new type NbdServerAddOptions that adds 'device' back because nbd-server-add doesn't use the BlockExportOptions base type at all (so even without changing it to a 'node-name' option in block-export-add, this compatibility code would be necessary). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-16-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>