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2023-05-30block/export: Fix null pointer dereference in error pathKevin Wolf1-2/+4
There are some error paths in blk_exp_add() that jump to 'fail:' before 'exp' is even created. So we can't just unconditionally access exp->blk. Add a NULL check, and switch from exp->blk to blk, which is available earlier, just to be extra sure that we really cover all cases where BlockDevOps could have been set for it (in practice, this only happens in drv->create() today, so this part of the change isn't strictly necessary). Fixes: Coverity CID 1509238 Fixes: de79b52604e43fdeba6cee4f5af600b62169f2d2 Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230510203601.418015-3-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> (cherry picked from commit a184563778f2b8970eb93291f08108e66432a575) Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2023-05-10block/export: call blk_set_dev_ops(blk, NULL, NULL)Stefan Hajnoczi1-0/+2
Most export types install BlockDeviceOps pointers. It is easy to forget to remove them because that happens automatically via the "drive" qdev property in hw/ but not block/export/. Put blk_set_dev_ops(blk, NULL, NULL) calls in the core export.c code so the export types don't need to remember. This fixes the nbd and vhost-user-blk export types. Fixes: fd6afc501a01 ("nbd/server: Use drained block ops to quiesce the server") Fixes: ca858a5fe94c ("vhost-user-blk-server: notify client about disk resize") Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20230502211119.720647-1-stefanha@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> (cherry picked from commit de79b52604e43fdeba6cee4f5af600b62169f2d2) Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2022-12-14qapi block: Elide redundant has_FOO in generated CMarkus Armbruster1-1/+1
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]
2022-10-27block: remove bdrv_try_set_aio_context and replace it with ↵Emanuele Giuseppe Esposito1-1/+1
bdrv_try_change_aio_context No functional change intended. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221025084952.2139888-11-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-06-24vduse-blk: Implement vduse-blk exportXie Yongji1-0/+6
This implements a VDUSE block backends based on the libvduse library. We can use it to export the BDSs for both VM and container (host) usage. The new command-line syntax is: $ qemu-storage-daemon \ --blockdev file,node-name=drive0,filename=test.img \ --export vduse-blk,node-name=drive0,id=vduse-export0,writable=on After the qemu-storage-daemon started, we need to use the "vdpa" command to attach the device to vDPA bus: $ vdpa dev add name vduse-export0 mgmtdev vduse Also the device must be removed via the "vdpa" command before we stop the qemu-storage-daemon. Signed-off-by: Xie Yongji <xieyongji@bytedance.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20220523084611.91-7-xieyongji@bytedance.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-03-04block: introduce bdrv_activateEmanuele Giuseppe Esposito1-1/+1
This function is currently just a wrapper for bdrv_invalidate_cache(), but in future will contain the code of bdrv_co_invalidate_cache() that has to always be protected by BQL, and leave the rest in the I/O coroutine. Replace all bdrv_invalidate_cache() invokations with bdrv_activate(). Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220209105452.1694545-4-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-07-20block/export: Conditionally ignore set-context errorMax Reitz1-1/+4
When invoking block-export-add with some iothread and fixed-iothread=false, and changing the node's iothread fails, the error is supposed to be ignored. However, it is still stored in *errp, which is wrong. If a second error occurs, the "*errp must be NULL" assertion in error_setv() fails: qemu-system-x86_64: ../util/error.c:59: error_setv: Assertion `*errp == NULL' failed. So if fixed-iothread=false, we should ignore the error by passing NULL to bdrv_try_set_aio_context(). Fixes: f51d23c80af73c95e0ce703ad06a300f1b3d63ef ("block/export: add iothread and fixed-iothread options") Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210624083825.29224-2-mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-01-28qapi: Use QAPI_LIST_APPEND in trivial casesEric Blake1-5/+2
The easiest spots to use QAPI_LIST_APPEND are where we already have an obvious pointer to the tail of a list. While at it, consistently use the variable name 'tail' for that purpose. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20210113221013.390592-5-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2020-12-11fuse: Allow exporting BDSs via FUSEMax Reitz1-0/+4
block-export-add type=fuse allows mounting block graph nodes via FUSE on some existing regular file. That file should then appears like a raw disk image, and accesses to it result in accesses to the exported BDS. Right now, we only implement the necessary block export functions to set it up and shut it down. We do not implement any access functions, so accessing the mount point only results in errors. This will be addressed by a followup patch. We keep a hash table of exported mount points, because we want to be able to detect when users try to use a mount point twice. This is because we invoke stat() to check whether the given mount point is a regular file, but if that file is served by ourselves (because it is already used as a mount point), then this stat() would have to be served by ourselves, too, which is impossible to do while we (as the caller) are waiting for it to settle. Therefore, keep track of mount point paths to at least catch the most obvious instances of that problem. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20201027190600.192171-3-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-11-03configure: introduce --enable-vhost-user-blk-serverStefan Hajnoczi1-2/+2
Make it possible to compile out the vhost-user-blk server. It is enabled by default on Linux. Note that vhost-user-server.c depends on libvhost-user, which requires CONFIG_LINUX. The CONFIG_VHOST_USER dependency was erroneous since that option controls vhost-user frontends (previously known as "master") and not device backends (previously known as "slave"). Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20201027173528.213464-3-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-10-23block/export: add iothread and fixed-iothread optionsStefan Hajnoczi1-1/+30
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>
2020-10-23util/vhost-user-server: use static library in meson.buildStefan Hajnoczi1-4/+4
Don't compile contrib/libvhost-user/libvhost-user.c again. Instead build the static library once and then reuse it throughout QEMU. Also switch from CONFIG_LINUX to CONFIG_VHOST_USER, which is what the vhost-user tools (vhost-user-gpu, etc) do. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20200924151549.913737-14-stefanha@redhat.com [Added CONFIG_LINUX again because libvhost-user doesn't build on macOS. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-10-23block/export: convert vhost-user-blk server to block export APIStefan Hajnoczi1-0/+6
Use the new QAPI block exports API instead of defining our own QOM objects. This is a large change because the lifecycle of VuBlockDev needs to follow BlockExportDriver. QOM properties are replaced by QAPI options objects. VuBlockDev is renamed VuBlkExport and contains a BlockExport field. Several fields can be dropped since BlockExport already has equivalents. The file names and meson build integration will be adjusted in a future patch. libvhost-user should probably be built as a static library that is linked into QEMU instead of as a .c file that results in duplicate compilation. The new command-line syntax is: $ qemu-storage-daemon \ --blockdev file,node-name=drive0,filename=test.img \ --export vhost-user-blk,node-name=drive0,id=export0,unix-socket=/tmp/vhost-user-blk.sock Note that unix-socket is optional because we may wish to accept chardevs too in the future. Markus noted that supported address families are not explicit in the QAPI schema. It is unlikely that support for more address families will be added since file descriptor passing is required and few address families support it. If a new address family needs to be added, then the QAPI 'features' syntax can be used to advertize them. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Message-id: 20200924151549.913737-12-stefanha@redhat.com [Skip test on big-endian host architectures because this device doesn't support them yet (as already mentioned in a code comment). --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-10-02block/export: Move writable to BlockExportOptionsKevin Wolf1-1/+15
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 query-block-exportsKevin Wolf1-0/+23
This adds a simple QMP command to query the list of block exports. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-25-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Create BlockBackend in blk_exp_add()Kevin Wolf1-4/+45
Every export type will need a BlockBackend, so creating it centrally in blk_exp_add() instead of the .create driver callback avoids duplication. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-24-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Move blk to BlockExportKevin Wolf1-0/+3
Every block export has a BlockBackend representing the disk that is exported. It should live in BlockExport therefore. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-23-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Add BLOCK_EXPORT_DELETED eventKevin Wolf1-0/+2
Clients may want to know when an export has finally disappeard (block-export-del returns earlier than that in the general case), so add a QAPI event for it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20200924152717.287415-22-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Add block-export-delKevin Wolf1-1/+42
Implement a new QMP command block-export-del and make nbd-server-remove a wrapper around it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-21-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Move strong user reference to block_exportsKevin Wolf1-0/+6
The reference owned by the user/monitor that is created when adding the export and dropped when removing it was tied to the 'exports' list in nbd/server.c. Every block export will have a user reference, so move it to the block export level and tie it to the 'block_exports' list in block/export/export.c instead. This is necessary for introducing a QMP command for removing exports. Note that exports are present in block_exports even after the user has requested shutdown. This is different from NBD's exports where exports are immediately removed on a shutdown request, even if they are still in the process of shutting down. In order to avoid that the user still interacts with an export that is shutting down (and possibly removes it a second time), we need to remember if the user actually still owns it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-20-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 Wolf1-0/+26
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 Wolf1-2/+84
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: Allocate BlockExport in blk_exp_add()Kevin Wolf1-1/+17
Instead of letting the driver allocate and return the BlockExport object, allocate it already in blk_exp_add() and pass it. This allows us to initialise the generic part before calling into the driver so that the driver can just use these values instead of having to parse the options a second time. For symmetry, move freeing the BlockExport to blk_exp_unref(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-17-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Move AioContext from NBDExport to BlockExportKevin Wolf1-0/+2
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-15-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Move refcount from NBDExport to BlockExportKevin Wolf1-0/+14
Having a refcount makes sense for all types of block exports. It is also a prerequisite for keeping a list of all exports at the BlockExport level. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-14-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Remove magic from block-export-addKevin Wolf1-3/+10
nbd-server-add tries to be convenient and adds two questionable features that we don't want to share in block-export-add, even for NBD exports: 1. When requesting a writable export of a read-only device, the export is silently downgraded to read-only. This should be an error in the context of block-export-add. 2. When using a BlockBackend name, unplugging the device from the guest will automatically stop the NBD server, too. This may sometimes be what you want, but it could also be very surprising. Let's keep things explicit with block-export-add. If the user wants to stop the export, they should tell us so. Move these things into the nbd-server-add QMP command handler so that they apply only there. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-8-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Add BlockExport infrastructure and block-export-addKevin Wolf1-0/+48
We want to have a common set of commands for all types of block exports. Currently, this is only NBD, but we're going to add more types. This patch adds the basic BlockExport and BlockExportDriver structs and a QMP command block-export-add that creates a new export based on the given BlockExportOptions. qmp_nbd_server_add() becomes a wrapper around qmp_block_export_add(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-5-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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