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* hw/9pfs/9p-synth: Replaced qemu_mutex_lock with QEMU_LOCK_GUARDMahmoud Mandour2021-03-161-8/+4Star
| | | | | | | | | | | | | Replaced a call to qemu_mutex_lock and its respective call to qemu_mutex_unlock and used QEMU_LOCK_GUARD macro in their place. This simplifies the code by removing the call required to unlock and also eliminates goto paths. Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com> Acked-by: Greg Kurz <groug@kaod.org> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20210311031538.5325-9-ma.mandourr@gmail.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* qtest: delete superfluous inclusions of qtest.hChen Qun2021-03-091-1/+0Star
| | | | | | | | | | There are 23 files that include the "sysemu/qtest.h", but they do not use any qtest functions. Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com> Acked-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20210226081414.205946-1-kuhn.chenqun@huawei.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
* 9pfs: Convert reclaim list to QSLISTGreg Kurz2021-01-222-10/+9Star
| | | | | | | | | | Use QSLIST instead of open-coding for a slightly improved readability. No behavioral change. Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20210122143514.215780-1-groug@kaod.org> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: Improve unreclaim loopGreg Kurz2021-01-221-14/+32
| | | | | | | | | | | | | | | | | | | | | | If a fid was actually re-opened by v9fs_reopen_fid(), we re-traverse the fid list from the head in case some other request created a fid that needs to be marked unreclaimable as well (i.e. the client opened a new handle on the path that is being unlinked). This is suboptimal since most if not all fids that require it have likely been taken care of already. This is mostly the result of new fids being added to the head of the list. Since the list is now a QSIMPLEQ, add new fids at the end instead to avoid the need to rewind. Take a reference on the fid to ensure it doesn't go away during v9fs_reopen_fid() and that it can be safely passed to QSIMPLEQ_NEXT() afterwards. Since the associated put_fid() can also yield, same is done with the next fid. So the logic here is to get a reference on a fid and only put it back during the next iteration after we could get a reference on the next fid. Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20210121181510.1459390-1-groug@kaod.org> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: Convert V9fsFidState::fid_list to QSIMPLEQGreg Kurz2021-01-212-25/+20Star
| | | | | | | | | | | The fid_list is currently open-coded. This doesn't seem to serve any purpose that cannot be met with QEMU's generic lists. Let's go for a QSIMPLEQ : this will allow to add new fids at the end of the list and to improve the logic in v9fs_mark_fids_unreclaim(). Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20210118142300.801516-3-groug@kaod.org> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: Convert V9fsFidState::clunked to boolGreg Kurz2021-01-212-3/+3
| | | | | | | | This can only be 0 or 1. Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20210118142300.801516-2-groug@kaod.org> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs/proxy: Check return value of proxy_marshal()Greg Kurz2021-01-211-1/+2
| | | | | | | | | | | | This should always successfully write exactly two 32-bit integers. Make it clear with an assert(), like v9fs_receive_status() and v9fs_receive_response() already do when unmarshalling the same header. Fixes: Coverity CID 1438968 Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <161035859647.1221144.4691749806675653934.stgit@bahia.lan> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: Fully restart unreclaim loop (CVE-2021-20181)Greg Kurz2021-01-151-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Depending on the client activity, the server can be asked to open a huge number of file descriptors and eventually hit RLIMIT_NOFILE. This is currently mitigated using a reclaim logic : the server closes the file descriptors of idle fids, based on the assumption that it will be able to re-open them later. This assumption doesn't hold of course if the client requests the file to be unlinked. In this case, we loop on the entire fid list and mark all related fids as unreclaimable (the reclaim logic will just ignore them) and, of course, we open or re-open their file descriptors if needed since we're about to unlink the file. This is the purpose of v9fs_mark_fids_unreclaim(). Since the actual opening of a file can cause the coroutine to yield, another client request could possibly add a new fid that we may want to mark as non-reclaimable as well. The loop is thus restarted if the re-open request was actually transmitted to the backend. This is achieved by keeping a reference on the first fid (head) before traversing the list. This is wrong in several ways: - a potential clunk request from the client could tear the first fid down and cause the reference to be stale. This leads to a use-after-free error that can be detected with ASAN, using a custom 9p client - fids are added at the head of the list : restarting from the previous head will always miss fids added by a some other potential request All these problems could be avoided if fids were being added at the end of the list. This can be achieved with a QSIMPLEQ, but this is probably too much change for a bug fix. For now let's keep it simple and just restart the loop from the current head. Fixes: CVE-2021-20181 Buglink: https://bugs.launchpad.net/qemu/+bug/1911666 Reported-by: Zero Day Initiative <zdi-disclosures@trendmicro.com> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Message-Id: <161064025265.1838153.15185571283519390907.stgit@bahia.lan> Signed-off-by: Greg Kurz <groug@kaod.org>
* hw/9pfs: Fix Kconfig dependency problem between 9pfs and XenPhilippe Mathieu-Daudé2020-11-052-5/+1Star
| | | | | | | | | | | | | | | | | | | | | | | | | | Commit b2c00bce54c ("meson: convert hw/9pfs, cleanup") introduced CONFIG_9PFS (probably a wrong conflict resolution). This config is not used anywhere. Backends depend on CONFIG_FSDEV_9P which itself depends on CONFIG_VIRTFS. Remove the invalid CONFIG_9PFS and use CONFIG_FSDEV_9P instead, to fix the './configure --without-default-devices --enable-xen' build: /usr/bin/ld: libcommon.fa.p/hw_xen_xen-legacy-backend.c.o: in function `xen_be_register_common': hw/xen/xen-legacy-backend.c:754: undefined reference to `xen_9pfs_ops' /usr/bin/ld: libcommon.fa.p/fsdev_qemu-fsdev.c.o:(.data.rel+0x8): undefined reference to `local_ops' /usr/bin/ld: libcommon.fa.p/fsdev_qemu-fsdev.c.o:(.data.rel+0x20): undefined reference to `synth_ops' /usr/bin/ld: libcommon.fa.p/fsdev_qemu-fsdev.c.o:(.data.rel+0x38): undefined reference to `proxy_ops' collect2: error: ld returned 1 exit status Fixes: b2c00bce54c ("meson: convert hw/9pfs, cleanup") Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Greg Kurz <groug@kaod.org> Tested-by: Greg Kurz <groug@kaod.org> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20201104115706.3101190-3-philmd@redhat.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* hw/9pfs : add space before the open parenthesis '('Xinhao Zhang2020-11-051-1/+1
| | | | | | | | | | | Fix code style. Space required before the open parenthesis '('. Signed-off-by: Xinhao Zhang <zhangxinhao1@huawei.com> Signed-off-by: Kai Deng <dengkai1@huawei.com> Reported-by: Euler Robot <euler.robot@huawei.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20201030043515.1030223-3-zhangxinhao1@huawei.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* hw/9pfs : open brace '{' following struct go on the same lineXinhao Zhang2020-11-051-6/+3Star
| | | | | | | | | | | Fix code style. Open braces for struct should go on the same line. Signed-off-by: Xinhao Zhang <zhangxinhao1@huawei.com> Signed-off-by: Kai Deng <dengkai1@huawei.com> Reported-by: Euler Robot <euler.robot@huawei.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20201030043515.1030223-2-zhangxinhao1@huawei.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* hw/9pfs : add spaces around operatorXinhao Zhang2020-11-052-13/+13
| | | | | | | | | | | Fix code style. Operator needs spaces both sides. Signed-off-by: Xinhao Zhang <zhangxinhao1@huawei.com> Signed-off-by: Kai Deng <dengkai1@huawei.com> Reported-by: Euler Robot <euler.robot@huawei.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20201030043515.1030223-1-zhangxinhao1@huawei.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* 9pfs: suppress performance warnings on qtest runsChristian Schoenebeck2020-10-192-2/+6
| | | | | | | | | | | | | Don't trigger any performance warning if we're just running test cases, because tests intentionally run for edge cases. So far performance warnings were suppressed for the 'synth' fs driver backend only. This patch suppresses them for all 9p fs driver backends. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <a2d2ff2163f8853ea782a7a1d4e6f2afd7c29ffe.1603106145.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* Use OBJECT_DECLARE_SIMPLE_TYPE when possibleEduardo Habkost2020-09-181-3/+1Star
| | | | | | | | | | | | | This converts existing DECLARE_INSTANCE_CHECKER usage to OBJECT_DECLARE_SIMPLE_TYPE when possible. $ ./scripts/codeconverter/converter.py -i \ --pattern=AddObjectDeclareSimpleType $(git grep -l '' -- '*.[ch]') Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Acked-by: Paul Durrant <paul@xen.org> Message-Id: <20200916182519.415636-6-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
* 9pfs: disable msize warning for synth driverChristian Schoenebeck2020-09-152-1/+3
| | | | | | | | | | | | | | | | | | | | | Previous patch introduced a performance warning being logged on host side if client connected with an 'msize' <= 8192. Disable this performance warning for the synth driver to prevent that warning from being printed whenever the 9pfs (qtest) test cases are running. Introduce a new export flag V9FS_NO_PERF_WARN for that purpose, which might also be used to disable such warnings from the CLI in future. We could have also prevented the warning by simply raising P9_MAX_SIZE in virtio-9p-test.c to any value larger than 8192, however in the context of test cases it makes sense running for edge cases, which includes the lowest 'msize' value supported by the server which is 4096, hence we want to preserve an msize of 4096 for the test client. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <E1kEyDy-0006nN-5A@lizzy.crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* 9pfs: log warning if msize <= 8192Christian Schoenebeck2020-09-151-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | It is essential to choose a reasonable high value for 'msize' to avoid severely degraded file I/O performance. This parameter can only be chosen on client/guest side, and a Linux client defaults to an 'msize' of only 8192 if the user did not explicitly specify a value for 'msize', which results in very poor file I/O performance. Unfortunately many users are not aware that they should specify an appropriate value for 'msize' to avoid severe performance issues, so log a performance warning (with a QEMU wiki link explaining this issue in detail) on host side in that case to make it more clear. Currently a client cannot automatically pick a reasonable value for 'msize', because a good value for 'msize' depends on the file I/O potential of the underlying storage on host side, i.e. a feature invisible to the client, and even then a user would still need to trade off between performance profit and additional RAM costs, i.e. with growing 'msize' (RAM occupation), performance still increases, but performance delta will shrink continuously. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <e6fc84845c95816ad5baecb0abd6bfefdcf7ec9f.1599144062.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* Use DECLARE_*CHECKER* macrosEduardo Habkost2020-09-091-2/+2
| | | | | | | | | | | | | | | Generated using: $ ./scripts/codeconverter/converter.py -i \ --pattern=TypeCheckMacro $(git grep -l '' -- '*.[ch]') Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20200831210740.126168-12-ehabkost@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20200831210740.126168-13-ehabkost@redhat.com> Message-Id: <20200831210740.126168-14-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
* Move QOM typedefs and add missing includesEduardo Habkost2020-09-091-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some typedefs and macros are defined after the type check macros. This makes it difficult to automatically replace their definitions with OBJECT_DECLARE_TYPE. Patch generated using: $ ./scripts/codeconverter/converter.py -i \ --pattern=QOMStructTypedefSplit $(git grep -l '' -- '*.[ch]') which will split "typdef struct { ... } TypedefName" declarations. Followed by: $ ./scripts/codeconverter/converter.py -i --pattern=MoveSymbols \ $(git grep -l '' -- '*.[ch]') which will: - move the typedefs and #defines above the type check macros - add missing #include "qom/object.h" lines if necessary Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20200831210740.126168-9-ehabkost@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20200831210740.126168-10-ehabkost@redhat.com> Message-Id: <20200831210740.126168-11-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
* Merge remote-tracking branch 'remotes/cschoenebeck/tags/pull-9p-20200812' ↵Peter Maydell2020-08-244-94/+333
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | into staging 9pfs: Fix severe performance issue of Treaddir requests. # gpg: Signature made Wed 12 Aug 2020 11:06:21 BST # gpg: using RSA key 96D8D110CF7AF8084F88590134C2B58765A47395 # gpg: issuer "qemu_oss@crudebyte.com" # gpg: Good signature from "Christian Schoenebeck <qemu_oss@crudebyte.com>" [unknown] # gpg: WARNING: This key is not certified with a trusted signature! # gpg: There is no indication that the signature belongs to the owner. # Primary key fingerprint: ECAB 1A45 4014 1413 BA38 4926 30DB 47C3 A012 D5F4 # Subkey fingerprint: 96D8 D110 CF7A F808 4F88 5901 34C2 B587 65A4 7395 * remotes/cschoenebeck/tags/pull-9p-20200812: 9pfs: clarify latency of v9fs_co_run_in_worker() 9pfs: differentiate readdir lock between 9P2000.u vs. 9P2000.L 9pfs: T_readdir latency optimization 9pfs: add new function v9fs_co_readdir_many() 9pfs: split out fs driver core of v9fs_co_readdir() 9pfs: make v9fs_readdir_response_size() public tests/virtio-9p: added split readdir tests Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| * 9pfs: clarify latency of v9fs_co_run_in_worker()Christian Schoenebeck2020-08-121-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | As we just fixed a severe performance issue with Treaddir request handling, clarify this overall issue as a comment on v9fs_co_run_in_worker() with the intention to hopefully prevent such performance mistakes in future (and fixing other yet outstanding ones). Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <4d34d332e1aaa8a2cf8dc0b5da4fd7727f2a86e8.1596012787.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
| * 9pfs: differentiate readdir lock between 9P2000.u vs. 9P2000.LChristian Schoenebeck2020-08-122-8/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previous patch suggests that it might make sense to use a different mutex type now while handling readdir requests, depending on the precise protocol variant, as v9fs_do_readdir_with_stat() (used by 9P2000.u) uses a CoMutex to avoid deadlocks that might happen with QemuMutex otherwise, whereas do_readdir_many() (used by 9P2000.L) should better use a QemuMutex, as the precise behaviour of a failed CoMutex lock on fs driver side would not be clear. And to avoid the wrong lock type being used, be now strict and error out if a 9P2000.L client sends a Tread on a directory, and likeweise error out if a 9P2000.u client sends a Treaddir request. This patch is just intended as transitional measure, as currently 9P2000.u vs. 9P2000.L implementations currently differ where the main logic of fetching directory entries is located at (9P2000.u still being more top half focused, while 9P2000.L already being bottom half focused in regards to fetching directory entries that is). Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <9a2ddc347e533b0d801866afd9dfac853d2d4106.1596012787.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
| * 9pfs: T_readdir latency optimizationChristian Schoenebeck2020-08-121-74/+58Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make top half really top half and bottom half really bottom half: Each T_readdir request handling is hopping between threads (main I/O thread and background I/O driver threads) several times for every individual directory entry, which sums up to huge latencies for handling just a single T_readdir request. Instead of doing that, collect now all required directory entries (including all potentially required stat buffers for each entry) in one rush on a background I/O thread from fs driver by calling the previously added function v9fs_co_readdir_many() instead of v9fs_co_readdir(), then assemble the entire resulting network response message for the readdir request on main I/O thread. The fs driver is still aborting the directory entry retrieval loop (on the background I/O thread inside of v9fs_co_readdir_many()) as soon as it would exceed the client's requested maximum R_readdir response size. So this will not introduce a performance penalty on another end. Also: No longer seek initial directory position in v9fs_readdir(), as this is now handled (more consistently) by v9fs_co_readdir_many() instead. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <c7c3d1cf4e86611538cef44897842819d9359d7a.1596012787.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
| * 9pfs: add new function v9fs_co_readdir_many()Christian Schoenebeck2020-08-123-0/+196
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The newly added function v9fs_co_readdir_many() retrieves multiple directory entries with a single fs driver request. It is intended to replace uses of v9fs_co_readdir(), the latter only retrieves a single directory entry per fs driver request instead. The reason for this planned replacement is that for every fs driver request the coroutine is dispatched from main I/O thread to a background I/O thread and eventually dispatched back to main I/O thread. Hopping between threads adds latency. So if a 9pfs Treaddir request reads a large amount of directory entries, this currently sums up to huge latencies of several hundred ms or even more. So using v9fs_co_readdir_many() instead of v9fs_co_readdir() will provide significant performance improvements. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <73dc827a12ef577ae7e644dcf34a5c0e443ab42f.1596012787.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
| * 9pfs: split out fs driver core of v9fs_co_readdir()Christian Schoenebeck2020-08-121-14/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The implementation of v9fs_co_readdir() has two parts: the outer part is executed by main I/O thread, whereas the inner part is executed by fs driver on a background I/O thread. Move the inner part to its own new, private function do_readdir(), so it can be shared by another upcoming new function. This is just a preparatory patch for the subsequent patch, with the purpose to avoid the next patch to clutter the overall diff. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <a426ee06e77584fa2d8253ce5d8bea519eb3ffd4.1596012787.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
| * 9pfs: make v9fs_readdir_response_size() publicChristian Schoenebeck2020-08-122-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | Rename function v9fs_readdir_data_size() -> v9fs_readdir_response_size() and make it callable from other units. So far this function is only used by 9p.c, however subsequent patches require the function to be callable from another 9pfs unit. And as we're at it; also make it clear for what this function is used for. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <3668ebc7d5b929a0e4f1357457060d96f50f76f4.1596012787.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* | meson: convert hw/9pfs, cleanupMarc-André Lureau2020-08-213-9/+24
| | | | | | | | | | | | | | hw/Makefile.objs is gone so there is more code that can be removed. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | trace: switch position of headers to what Meson requiresPaolo Bonzini2020-08-211-0/+1
|/ | | | | | | | | | | | | | | | | Meson doesn't enjoy the same flexibility we have with Make in choosing the include path. In particular the tracing headers are using $(build_root)/$(<D). In order to keep the include directives unchanged, the simplest solution is to generate headers with patterns like "trace/trace-audio.h" and place forwarding headers in the source tree such that for example "audio/trace.h" includes "trace/trace-audio.h". This patch is too ugly to be applied to the Makefiles now. It's only a way to separate the changes to the tracing header files from the Meson rewrite of the tracing logic. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* virtio-9p: Use ERRP_GUARD()Vladimir Sementsov-Ogievskiy2020-07-102-7/+6Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we want to check error after errp-function call, we need to introduce local_err and then propagate it to errp. Instead, use the ERRP_GUARD() macro, benefits are: 1. No need of explicit error_propagate call 2. No need of explicit local_err variable: use errp directly 3. ERRP_GUARD() leaves errp as is if it's not NULL or &error_fatal, this means that we don't break error_abort (we'll abort on error_set, not on error_propagate) If we want to add some info to errp (by error_prepend() or error_append_hint()), we must use the ERRP_GUARD() macro. Otherwise, this info will not be added when errp == &error_fatal (the program will exit prior to the error_append_hint() or error_prepend() call). Fix such a case in v9fs_device_realize_common(). This commit is generated by command sed -n '/^virtio-9p$/,/^$/{s/^F: //p}' MAINTAINERS | \ xargs git ls-files | grep '\.[hc]$' | \ xargs spatch \ --sp-file scripts/coccinelle/errp-guard.cocci \ --macro-file scripts/cocci-macro-file.h \ --in-place --no-show-diff --max-width 80 Reported-by: Kevin Wolf <kwolf@redhat.com> Reported-by: Greg Kurz <groug@kaod.org> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Acked-by: Greg Kurz <groug@kaod.org> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> [Commit message tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200707165037.1026246-7-armbru@redhat.com> [ERRP_AUTO_PROPAGATE() renamed to ERRP_GUARD(), and auto-propagated-errp.cocci to errp-guard.cocci. Commit message tweaked again.]
* Clean up some calls to ignore Error objects the right wayMarkus Armbruster2020-07-021-4/+2Star
| | | | | | | | | | | | | Receiving the error in a local variable only to free it is less clear (and also less efficient) than passing NULL. Clean up. Cc: Daniel P. Berrange <berrange@redhat.com> Cc: Jerome Forissier <jerome@forissier.org> CC: Greg Kurz <groug@kaod.org> Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20200630090351.1247703-4-armbru@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
* xen/9pfs: increase max ring order to 9Stefano Stabellini2020-05-251-1/+1
| | | | | | | | | | The max order allowed by the protocol is 9. Increase the max order supported by QEMU to 9 to increase performance. Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20200521192627.15259-3-sstabellini@kernel.org> Signed-off-by: Greg Kurz <groug@kaod.org>
* xen/9pfs: yield when there isn't enough room on the ringStefano Stabellini2020-05-251-6/+25
| | | | | | | | | | | | | | | | | | | | Instead of truncating replies, which is problematic, wait until the client reads more data and frees bytes on the reply ring. Do that by calling qemu_coroutine_yield(). The corresponding qemu_coroutine_enter_if_inactive() is called from xen_9pfs_bh upon receiving the next notification from the client. We need to be careful to avoid races in case xen_9pfs_bh and the coroutine are both active at the same time. In xen_9pfs_bh, wait until either the critical section is over (ring->co == NULL) or until the coroutine becomes inactive (qemu_coroutine_yield() was called) before continuing. Then, simply wake up the coroutine if it is inactive. Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20200521192627.15259-2-sstabellini@kernel.org> Signed-off-by: Greg Kurz <groug@kaod.org>
* Revert "9p: init_in_iov_from_pdu can truncate the size"Stefano Stabellini2020-05-254-39/+22Star
| | | | | | | | | | This reverts commit 16724a173049ac29c7b5ade741da93a0f46edff7. It causes https://bugs.launchpad.net/bugs/1877688. Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20200521192627.15259-1-sstabellini@kernel.org> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9p: Lock directory streams with a CoMutexGreg Kurz2020-05-251-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | Locking was introduced in QEMU 2.7 to address the deprecation of readdir_r(3) in glibc 2.24. It turns out that the frontend code is the worst place to handle a critical section with a pthread mutex: the code runs in a coroutine on behalf of the QEMU mainloop and then yields control, waiting for the fsdev backend to process the request in a worker thread. If the client resends another readdir request for the same fid before the previous one finally unlocked the mutex, we're deadlocked. This never bit us because the linux client serializes readdir requests for the same fid, but it is quite easy to demonstrate with a custom client. A good solution could be to narrow the critical section in the worker thread code and to return a copy of the dirent to the frontend, but this causes quite some changes in both 9p.c and codir.c. So, instead of that, in order for people to easily backport the fix to older QEMU versions, let's simply use a CoMutex since all the users for this sit in coroutines. Fixes: 7cde47d4a89d ("9p: add locking to V9fsDir") Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <158981894794.109297.3530035833368944254.stgit@bahia.lan> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: include linux/limits.h for XATTR_SIZE_MAXDan Robertson2020-05-251-0/+1
| | | | | | | | | | | | linux/limits.h should be included for the XATTR_SIZE_MAX definition used by v9fs_xattrcreate. Fixes: 3b79ef2cf488 ("9pfs: limit xattr size in xattrcreate") Signed-off-by: Dan Robertson <dan@dlrobertson.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <20200515203015.7090-2-dan@dlrobertson.com> Signed-off-by: Greg Kurz <groug@kaod.org>
* qdev: Unrealize must not failMarkus Armbruster2020-05-153-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Devices may have component devices and buses. Device realization may fail. Realization is recursive: a device's realize() method realizes its components, and device_set_realized() realizes its buses (which should in turn realize the devices on that bus, except bus_set_realized() doesn't implement that, yet). When realization of a component or bus fails, we need to roll back: unrealize everything we realized so far. If any of these unrealizes failed, the device would be left in an inconsistent state. Must not happen. device_set_realized() lets it happen: it ignores errors in the roll back code starting at label child_realize_fail. Since realization is recursive, unrealization must be recursive, too. But how could a partly failed unrealize be rolled back? We'd have to re-realize, which can fail. This design is fundamentally broken. device_set_realized() does not roll back at all. Instead, it keeps unrealizing, ignoring further errors. It can screw up even for a device with no buses: if the lone dc->unrealize() fails, it still unregisters vmstate, and calls listeners' unrealize() callback. bus_set_realized() does not roll back either. Instead, it stops unrealizing. Fortunately, no unrealize method can fail, as we'll see below. To fix the design error, drop parameter @errp from all the unrealize methods. Any unrealize method that uses @errp now needs an update. This leads us to unrealize() methods that can fail. Merely passing it to another unrealize method cannot cause failure, though. Here are the ones that do other things with @errp: * virtio_serial_device_unrealize() Fails when qbus_set_hotplug_handler() fails, but still does all the other work. On failure, the device would stay realized with its resources completely gone. Oops. Can't happen, because qbus_set_hotplug_handler() can't actually fail here. Pass &error_abort to qbus_set_hotplug_handler() instead. * hw/ppc/spapr_drc.c's unrealize() Fails when object_property_del() fails, but all the other work is already done. On failure, the device would stay realized with its vmstate registration gone. Oops. Can't happen, because object_property_del() can't actually fail here. Pass &error_abort to object_property_del() instead. * spapr_phb_unrealize() Fails and bails out when remove_drcs() fails, but other work is already done. On failure, the device would stay realized with some of its resources gone. Oops. remove_drcs() fails only when chassis_from_bus()'s object_property_get_uint() fails, and it can't here. Pass &error_abort to remove_drcs() instead. Therefore, no unrealize method can fail before this patch. device_set_realized()'s recursive unrealization via bus uses object_property_set_bool(). Can't drop @errp there, so pass &error_abort. We similarly unrealize with object_property_set_bool() elsewhere, always ignoring errors. Pass &error_abort instead. Several unrealize methods no longer handle errors from other unrealize methods: virtio_9p_device_unrealize(), virtio_input_device_unrealize(), scsi_qdev_unrealize(), ... Much of the deleted error handling looks wrong anyway. One unrealize methods no longer ignore such errors: usb_ehci_pci_exit(). Several realize methods no longer ignore errors when rolling back: v9fs_device_realize_common(), pci_qdev_unrealize(), spapr_phb_realize(), usb_qdev_realize(), vfio_ccw_realize(), virtio_device_realize(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20200505152926.18877-17-armbru@redhat.com>
* xen-9pfs: Fix log messages of reply errorsChristian Schoenebeck2020-05-141-4/+5
| | | | | | | | | | | | If delivery of some 9pfs response fails for some reason, log the error message by mentioning the 9P protocol reply type, not by client's request type. The latter could be misleading that the error occurred already when handling the request input. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Message-Id: <ad0e5a9b6abde52502aa40b30661d29aebe1590a.1589132512.git.qemu_oss@crudebyte.com> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: local: ignore O_NOATIME if we don't have permissionsOmar Sandoval2020-05-141-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | QEMU's local 9pfs server passes through O_NOATIME from the client. If the QEMU process doesn't have permissions to use O_NOATIME (namely, it does not own the file nor have the CAP_FOWNER capability), the open will fail. This causes issues when from the client's point of view, it believes it has permissions to use O_NOATIME (e.g., a process running as root in the virtual machine). Additionally, overlayfs on Linux opens files on the lower layer using O_NOATIME, so in this case a 9pfs mount can't be used as a lower layer for overlayfs (cf. https://github.com/osandov/drgn/blob/dabfe1971951701da13863dbe6d8a1d172ad9650/vmtest/onoatimehack.c and https://github.com/NixOS/nixpkgs/issues/54509). Luckily, O_NOATIME is effectively a hint, and is often ignored by, e.g., network filesystems. open(2) notes that O_NOATIME "may not be effective on all filesystems. One example is NFS, where the server maintains the access time." This means that we can honor it when possible but fall back to ignoring it. Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Message-Id: <e9bee604e8df528584693a4ec474ded6295ce8ad.1587149256.git.osandov@fb.com> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9p/proxy: Fix export_flagsGreg Kurz2020-03-101-2/+2
| | | | | | | | | | | | | The common fsdev options are set by qemu_fsdev_add() before it calls the backend specific option parsing code. In the case of "proxy" this means "writeout" or "readonly" were simply ignored. This has been broken from the beginning. Reported-by: Stéphane Graber <stgraber@ubuntu.com> Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <158349633705.1237488.8895481990204796135.stgit@bahia.lan>
* hw/9pfs/9p-synth: added directory for readdir testChristian Schoenebeck2020-02-082-0/+24
| | | | | | | | | | | | | | | | | | | This will provide the following virtual files by the 9pfs synth driver: - /ReadDirDir/ReadDirFile99 - /ReadDirDir/ReadDirFile98 ... - /ReadDirDir/ReadDirFile1 - /ReadDirDir/ReadDirFile0 This virtual directory and its virtual 100 files will be used by the upcoming 9pfs readdir tests. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <5408c28c8de25dd575b745cef63bf785305ccef2.1579567020.git.qemu_oss@crudebyte.com> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: validate count sent by client with T_readdirChristian Schoenebeck2020-02-081-0/+9
| | | | | | | | | | | | | | | A good 9p client sends T_readdir with "count" parameter that's sufficiently smaller than client's initially negotiated msize (maximum message size). We perform a check for that though to avoid the server to be interrupted with a "Failed to encode VirtFS reply type 41" transport error message by bad clients. This count value constraint uses msize - 11, because 11 is the header size of R_readdir. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <3990d3891e8ae2074709b56449e96ab4b4b93b7d.1579567020.git.qemu_oss@crudebyte.com> [groug: added comment ] Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: require msize >= 4096Christian Schoenebeck2020-02-082-0/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A client establishes a session by sending a Tversion request along with a 'msize' parameter which client uses to suggest server a maximum message size ever to be used for communication (for both requests and replies) between client and server during that session. If client suggests a 'msize' smaller than 4096 then deny session by server immediately with an error response (Rlerror for "9P2000.L" clients or Rerror for "9P2000.u" clients) instead of replying with Rversion. So far any msize submitted by client with Tversion was simply accepted by server without any check. Introduction of some minimum msize makes sense, because e.g. a msize < 7 would not allow any subsequent 9p operation at all, because 7 is the size of the header section common by all 9p message types. A substantial higher value of 4096 was chosen though to prevent potential issues with some message types. E.g. Rreadlink may yield up to a size of PATH_MAX which is usually 4096, and like almost all 9p message types, Rreadlink is not allowed to be truncated by the 9p protocol. This chosen size also prevents a similar issue with Rreaddir responses (provided client always sends adequate 'count' parameter with Treaddir), because even though directory entries retrieval may be split up over several T/Rreaddir messages; a Rreaddir response must not truncate individual directory entries though. So msize should be large enough to return at least one directory entry with the longest possible file name supported by host. Most file systems support a max. file name length of 255. Largest known file name lenght limit would be currently ReiserFS with max. 4032 bytes, which is also covered by this min. msize value because 4032 + 35 < 4096. Furthermore 4096 is already the minimum msize of the Linux kernel's 9pfs client. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <8ceecb7fb9fdbeabbe55c04339349a36929fb8e3.1579567019.git.qemu_oss@crudebyte.com> Signed-off-by: Greg Kurz <groug@kaod.org>
* Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into stagingPeter Maydell2020-01-271-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * Register qdev properties as class properties (Marc-André) * Cleanups (Philippe) * virtio-scsi fix (Pan Nengyuan) * Tweak Skylake-v3 model id (Kashyap) * x86 UCODE_REV support and nested live migration fix (myself) * Advisory mode for pvpanic (Zhenwei) # gpg: Signature made Fri 24 Jan 2020 20:16:23 GMT # gpg: using RSA key BFFBD25F78C7AE83 # gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full] # gpg: aka "Paolo Bonzini <pbonzini@redhat.com>" [full] # Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4 E2F7 7E15 100C CD36 69B1 # Subkey fingerprint: F133 3857 4B66 2389 866C 7682 BFFB D25F 78C7 AE83 * remotes/bonzini/tags/for-upstream: (58 commits) build-sys: clean up flags included in the linker command line target/i386: Add the 'model-id' for Skylake -v3 CPU models qdev: use object_property_help() qapi/qmp: add ObjectPropertyInfo.default-value qom: introduce object_property_help() qom: simplify qmp_device_list_properties() vl: print default value in object help qdev: register properties as class properties qdev: move instance properties to class properties qdev: rename DeviceClass.props qdev: set properties with device_class_set_props() object: return self in object_ref() object: release all props object: add object_class_property_add_link() object: express const link with link property object: add direct link flag object: rename link "child" to "target" object: check strong flag with & object: do not free class properties object: add object_property_set_default ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| * qdev: set properties with device_class_set_props()Marc-André Lureau2020-01-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following patch will need to handle properties registration during class_init time. Let's use a device_class_set_props() setter. spatch --macro-file scripts/cocci-macro-file.h --sp-file ./scripts/coccinelle/qdev-set-props.cocci --keep-comments --in-place --dir . @@ typedef DeviceClass; DeviceClass *d; expression val; @@ - d->props = val + device_class_set_props(d, val) Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20200110153039.1379601-20-marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | virtio-9p-device: convert to new virtio_delete_queuePan Nengyuan2020-01-221-1/+1
| | | | | | | | | | | | | | | | | | | | Use virtio_delete_queue to make it more clear. Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com> Message-Id: <20200117060927.51996-3-pannengyuan@huawei.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* | virtio-9p-device: fix memleak in virtio_9p_device_unrealizePan Nengyuan2020-01-221-0/+1
|/ | | | | | | | | | | | | | | | | | | | | v->vq forgot to cleanup in virtio_9p_device_unrealize, the memory leak stack is as follow: Direct leak of 14336 byte(s) in 2 object(s) allocated from: #0 0x7f819ae43970 (/lib64/libasan.so.5+0xef970) ??:? #1 0x7f819872f49d (/lib64/libglib-2.0.so.0+0x5249d) ??:? #2 0x55a3a58da624 (./x86_64-softmmu/qemu-system-x86_64+0x2c14624) /mnt/sdb/qemu/hw/virtio/virtio.c:2327 #3 0x55a3a571bac7 (./x86_64-softmmu/qemu-system-x86_64+0x2a55ac7) /mnt/sdb/qemu/hw/9pfs/virtio-9p-device.c:209 #4 0x55a3a58e7bc6 (./x86_64-softmmu/qemu-system-x86_64+0x2c21bc6) /mnt/sdb/qemu/hw/virtio/virtio.c:3504 #5 0x55a3a5ebfb37 (./x86_64-softmmu/qemu-system-x86_64+0x31f9b37) /mnt/sdb/qemu/hw/core/qdev.c:876 Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com> Message-Id: <20200117060927.51996-2-pannengyuan@huawei.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Acked-by: Greg Kurz <groug@kaod.org>
* 9pfs/9p.c: remove unneeded labelsDaniel Henrique Barboza2020-01-201-6/+3Star
| | | | | | | | | | | 'out' label in v9fs_xattr_write() and 'out_nofid' label in v9fs_complete_rename() can be replaced by appropriate return calls. CC: Greg Kurz <groug@kaod.org> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> Acked-by: Greg Kurz <groug@kaod.org> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9p: init_in_iov_from_pdu can truncate the sizeGreg Kurz2020-01-204-21/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | init_in_iov_from_pdu might not be able to allocate the full buffer size requested, which comes from the client and could be larger than the transport has available at the time of the request. Specifically, this can happen with read operations, with the client requesting a read up to the max allowed, which might be more than the transport has available at the time. Today the implementation of init_in_iov_from_pdu throws an error, both Xen and Virtio. Instead, change the V9fsTransport interface so that the size becomes a pointer and can be limited by the implementation of init_in_iov_from_pdu. Change both the Xen and Virtio implementations to set the size to the size of the buffer they managed to allocate, instead of throwing an error. However, if the allocated buffer size is less than P9_IOHDRSZ (the size of the header) still throw an error as the case is unhandable. Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> CC: groug@kaod.org CC: anthony.perard@citrix.com CC: roman@zededa.com CC: qemu_oss@crudebyte.com [groug: fix 32-bit build] Signed-off-by: Greg Kurz <groug@kaod.org>
* 9p: local: always return -1 on error in local_unlinkat_commonDaniel Henrique Barboza2020-01-201-8/+6Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | local_unlinkat_common() is supposed to always return -1 on error. This is being done by jumps to the 'err_out' label, which is a 'return ret' call, and 'ret' is initialized with -1. Unfortunately there is a condition in which the function will return 0 on error: in a case where flags == AT_REMOVEDIR, 'ret' will be 0 when reaching map_dirfd = openat_dir(...) And, if map_dirfd == -1 and errno != ENOENT, the existing 'err_out' jump will execute 'return ret', when ret is still set to zero at that point. This patch fixes it by changing all 'err_out' labels by 'return -1' calls, ensuring that the function will always return -1 on error conditions. 'ret' can be left unintialized since it's now being used just to store the result of 'unlinkat' calls. CC: Greg Kurz <groug@kaod.org> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> [groug: changed prefix in title to be "9p: local:"] Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: local: Fix possible memory leak in local_link()Jiajun Chen2020-01-201-1/+1
| | | | | | | | | | | | There is a possible memory leak while local_link return -1 without free odirpath and oname. Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Jaijun Chen <chenjiajun8@huawei.com> Signed-off-by: Xiang Zheng <zhengxiang9@huawei.com> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: make Error **errp const where it is appropriateVladimir Sementsov-Ogievskiy2019-12-182-2/+2
| | | | | | | | | | | | | | | | | Mostly, Error ** is for returning error from the function, so the callee sets it. However error_append_security_model_hint and error_append_socket_sockfd_hint get already filled errp parameter. They don't change the pointer itself, only change the internal state of referenced Error object. So we can make it Error *const * errp, to stress the behavior. It will also help coccinelle script (in future) to distinguish such cases from common errp usage. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Acked-by: Greg Kurz <groug@kaod.org> Message-Id: <20191205174635.18758-9-vsementsov@virtuozzo.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Commit message replaced] Signed-off-by: Markus Armbruster <armbru@redhat.com>