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2024-09-10qapi/block-core: Drop temporary 'prefix'Markus Armbruster
Recent commit "qapi: Smarter camel_to_upper() to reduce need for 'prefix'" added a temporary 'prefix' to delay changing the generated code. Revert it. This improves XDbgBlockGraphNodeType's generated enumeration constant prefix from X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND to XDBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-ID: <20240904111836.3273842-4-armbru@redhat.com>
2024-07-02block: Parse filenames only when explicitly requestedKevin Wolf
When handling image filenames from legacy options such as -drive or from tools, these filenames are parsed for protocol prefixes, including for the json:{} pseudo-protocol. This behaviour is intended for filenames that come directly from the command line and for backing files, which may come from the image file itself. Higher level management tools generally take care to verify that untrusted images don't contain a bad (or any) backing file reference; 'qemu-img info' is a suitable tool for this. However, for other files that can be referenced in images, such as qcow2 data files or VMDK extents, the string from the image file is usually not verified by management tools - and 'qemu-img info' wouldn't be suitable because in contrast to backing files, it already opens these other referenced files. So here the string should be interpreted as a literal local filename. More complex configurations need to be specified explicitly on the command line or in QMP. This patch changes bdrv_open_inherit() so that it only parses filenames if a new parameter parse_filename is true. It is set for the top level in bdrv_open(), for the file child and for the backing file child. All other callers pass false and disable filename parsing this way. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
2024-06-28block: remove separate bdrv_file_open callbackPaolo Bonzini
bdrv_file_open and bdrv_open are completely equivalent, they are never checked except to see which one to invoke. So merge them into a single one. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-28block: do not check bdrv_file_openPaolo Bonzini
The set of BlockDrivers that have .bdrv_file_open coincides with those that have .protocol_name and guess what---checking drv->bdrv_file_open is done to see if the driver is a protocol. So check drv->protocol_name instead. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-28block: make assertion more genericPaolo Bonzini
.bdrv_needs_filename is only set for drivers that also set bdrv_file_open, i.e. protocol drivers. So we can make the assertion always, it will always pass for those drivers that use bdrv_open. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-03-12error: Move ERRP_GUARD() to the beginning of the functionZhao Liu
Since the commit 05e385d2a9 ("error: Move ERRP_GUARD() to the beginning of the function"), there are new codes that don't put ERRP_GUARD() at the beginning of the functions. As stated in the commit 05e385d2a9: "include/qapi/error.h advises to put ERRP_GUARD() right at the beginning of the function, because only then can it guard the whole function.", so clean up the few spots disregarding the advice. Inspired-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Zhao Liu <zhao1.liu@intel.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-ID: <20240312060337.3240965-1-zhao1.liu@linux.intel.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2024-03-12block: Fix missing ERRP_GUARD() for error_prepend()Zhao Liu
As the comment in qapi/error, passing @errp to error_prepend() requires ERRP_GUARD(): * = Why, when and how to use ERRP_GUARD() = * * Without ERRP_GUARD(), use of the @errp parameter is restricted: ... * - It should not be passed to error_prepend(), error_vprepend() or * error_append_hint(), because that doesn't work with &error_fatal. * ERRP_GUARD() lifts these restrictions. * * To use ERRP_GUARD(), add it right at the beginning of the function. * @errp can then be used without worrying about the argument being * NULL or &error_fatal. ERRP_GUARD() could avoid the case when @errp is &error_fatal, the user can't see this additional information, because exit() happens in error_setg earlier than information is added [1]. In block.c, there are 4 functions passing @errp to error_prepend() without ERRP_GUARD(): - bdrv_co_create_opts_simple() - parse_json_filename() - bdrv_open_backing_file() - bdrv_append_temp_snapshot() bdrv_co_create_opts_simple(), is an implementation of BlockDriver.bdrv_co_create_opts(). There are too many possible callers to check the impact of this defect; it may or may not be harmless. Thus it is necessary to protect @errp with ERRP_GUARD(). Though the @errp parameters passed to parse_json_filename(), bdrv_open_backing_file() and bdrv_append_temp_snapshot() points to their callers' local_err, to follow the requirement of @errp, also add missing ERRP_GUARD() at their beginning. [1]: Issue description in the commit message of commit ae7c80a7bd73 ("error: New macro ERRP_GUARD()"). Cc: Kevin Wolf <kwolf@redhat.com> Cc: Hanna Reitz <hreitz@redhat.com> Cc: qemu-block@nongnu.org Signed-off-by: Zhao Liu <zhao1.liu@intel.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-ID: <20240311033822.3142585-4-zhao1.liu@linux.intel.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2024-02-09block: Support detached LUKS header creation using qemu-imgHyman Huang
Even though a LUKS header might be created with cryptsetup, qemu-img should be enhanced to accommodate it as well. Add the 'detached-header' option to specify the creation of a detached LUKS header. This is how it is used: $ qemu-img create --object secret,id=sec0,data=abc123 -f luks > -o cipher-alg=aes-256,cipher-mode=xts -o key-secret=sec0 > -o detached-header=true header.luks Using qemu-img or cryptsetup tools to query information of an LUKS header image as follows: Assume a detached LUKS header image has been created by: $ dd if=/dev/zero of=test-header.img bs=1M count=32 $ dd if=/dev/zero of=test-payload.img bs=1M count=1000 $ cryptsetup luksFormat --header test-header.img test-payload.img > --force-password --type luks1 Header image information could be queried using cryptsetup: $ cryptsetup luksDump test-header.img or qemu-img: $ qemu-img info 'json:{"driver":"luks","file":{"filename": > "test-payload.img"},"header":{"filename":"test-header.img"}}' When using qemu-img, keep in mind that the entire disk information specified by the JSON-format string above must be supplied on the commandline; if not, an overlay check will reveal a problem with the LUKS volume check logic. Signed-off-by: Hyman Huang <yong.huang@smartx.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> [changed to pass 'cflags' to block_crypto_co_create_generic] Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2024-01-26commit: Allow users to request only format driver names in backing file formatPeter Krempa
Introduce a new flag 'backing-mask-protocol' for the block-commit QMP command which instructs the internals to use 'raw' instead of the protocol driver in case when a image is used without a dummy 'raw' wrapper. The flag is designed such that it can be always asserted by management tools even when there isn't any update to backing files. The flag will be used by libvirt so that the backing images still reference the proper format even when libvirt will stop using the dummy raw driver (raw driver with no other config). Libvirt needs this so that the images stay compatible with older libvirt versions which didn't expect that a protocol driver name can appear in the backing file format field. Signed-off-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <2cb46e37093ce793ea1604abc8bbb90f4c8e434b.1701796348.git.pkrempa@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-12-21block: remove outdated AioContext locking commentsStefan Hajnoczi
The AioContext lock no longer exists. There is one noteworthy change: - * More specifically, these functions use BDRV_POLL_WHILE(bs), which - * requires the caller to be either in the main thread and hold - * the BlockdriverState (bs) AioContext lock, or directly in the - * home thread that runs the bs AioContext. Calling them from - * another thread in another AioContext would cause deadlocks. + * More specifically, these functions use BDRV_POLL_WHILE(bs), which requires + * the caller to be either in the main thread or directly in the home thread + * that runs the bs AioContext. Calling them from another thread in another + * AioContext would cause deadlocks. I am not sure whether deadlocks are still possible. Maybe they have just moved to the fine-grained locks that have replaced the AioContext. Since I am not sure if the deadlocks are gone, I have kept the substance unchanged and just removed mention of the AioContext. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-ID: <20231205182011.1976568-15-stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-12-21block: remove bdrv_co_lock()Stefan Hajnoczi
The bdrv_co_lock() and bdrv_co_unlock() functions are already no-ops. Remove them. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20231205182011.1976568-8-stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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>
2023-12-21graph-lock: remove AioContext lockingStefan Hajnoczi
Stop acquiring/releasing the AioContext lock in bdrv_graph_wrlock()/bdrv_graph_unlock() since the lock no longer has any effect. The distinction between bdrv_graph_wrunlock() and bdrv_graph_wrunlock_ctx() becomes meaningless and they can be collapsed into one function. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231205182011.1976568-6-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-21block: Fix deadlocks in bdrv_graph_wrunlock()Kevin Wolf
bdrv_graph_wrunlock() calls aio_poll(), which may run callbacks that have a nested event loop. Nested event loops can depend on other iothreads making progress, so in order to allow them to make progress it must not hold the AioContext lock of another thread while calling aio_poll(). This introduces a @bs parameter to bdrv_graph_wrunlock() whose AioContext is temporarily dropped (which matches bdrv_graph_wrlock()), and a bdrv_graph_wrunlock_ctx() that can be used if the BlockDriverState doesn't necessarily exist any more when unlocking. This also requires a change to bdrv_schedule_unref(), which was relying on the incorrectly taken lock. It needs to take the lock itself now. While this is a separate bug, it can't be fixed a separate patch because otherwise the intermediate state would either deadlock or try to release a lock that we don't even hold. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231115172012.112727-3-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> [kwolf: Fixed up bdrv_schedule_unref()] Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-08block: Protect bs->file with graph_lockKevin Wolf
Almost all functions that access bs->file already take the graph lock now. Add locking to the remaining users and finally annotate the struct field itself as protected by the graph lock. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-25-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-08block: Introduce bdrv_co_change_backing_file()Kevin Wolf
bdrv_change_backing_file() is called both inside and outside coroutine context. This makes it difficult for it to take the graph lock internally. It also means that driver implementations need to be able to run outside of coroutines, too. Switch it to the usual model with a coroutine based implementation and a co_wrapper instead. The new function is marked GRAPH_RDLOCK. As the co_wrapper now runs the function in the AioContext of the node (as it should always have done), this is not GLOBAL_STATE_CODE() any more. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-20-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-08block: Protect bs->backing with graph_lockKevin Wolf
Almost all functions that access bs->backing already take the graph lock now. Add locking to the remaining users and finally annotate the struct field itself as protected by the graph lock. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-18-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_replace_node() GRAPH_WRLOCKKevin Wolf
Instead of taking the writer lock internally, require callers to already hold it when calling bdrv_replace_node(). Its callers may already want to hold the graph lock and so wouldn't be able to call functions that take it internally. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-17-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_replace_node_common() GRAPH_WRLOCKKevin Wolf
Instead of taking the writer lock internally, require callers to already hold it when calling bdrv_replace_node_common(). Basically everthing in the function needs the lock and its callers may already want to hold the graph lock and so wouldn't be able to call functions that take it internally. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-16-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Inline bdrv_set_backing_noperm()Kevin Wolf
It's only a single line and has a single caller. Inlining makes things a bit easier to follow. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-15-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_set_backing_hd_drained() GRAPH_WRLOCKKevin Wolf
Instead of taking the writer lock internally, require callers to already hold it when calling bdrv_set_backing_hd_drained(). Basically everthing in the function needs the lock and its callers may already want to hold the graph lock and so wouldn't be able to call functions that take it internally. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-14-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_filter_child() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_filter_child() need to hold a reader lock for the graph because it accesses bs->file/backing. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-12-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_chain_contains() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_chain_contains() need to hold a reader lock for the graph because it calls bdrv_filter_or_cow_bs(), which accesses bs->file/backing. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-11-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_(un)freeze_backing_chain() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_(un)freeze_backing_chain() need to hold a reader lock for the graph because it calls bdrv_filter_or_cow_child(), which accesses bs->file/backing. Use the opportunity to make bdrv_is_backing_chain_frozen() static, it has no external callers. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-10-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_skip_implicit_filters() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_skip_implicit_filters() need to hold a reader lock for the graph because it calls bdrv_filter_child(), which accesses bs->file/backing. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-8-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_filter_or_cow_bs() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_filter_or_cow_bs() need to hold a reader lock for the graph because it calls bdrv_filter_or_cow_child(), which accesses bs->file/backing. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-7-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_root_attach_child() GRAPH_WRLOCKKevin Wolf
Instead of taking the writer lock internally, require callers to already hold it when calling bdrv_root_attach_child(). These callers will typically already hold the graph lock once the locking work is completed, which means that they can't call functions that take it internally. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-5-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_filter_bs() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_filter_bs() need to hold a reader lock for the graph because it calls bdrv_filter_child(), which accesses bs->file/backing. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-4-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-07block: Mark bdrv_has_zero_init() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_has_zero_init() need to hold a reader lock for the graph because it calls bdrv_filter_bs(), which accesses bs->file/backing. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231027155333.420094-3-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-31block: avoid potential deadlock during bdrv_graph_wrlock() in bdrv_close()Fiona Ebner
by passing the BlockDriverState along, so the held AioContext can be dropped before polling. See commit 31b2ddfea3 ("graph-lock: Unlock the AioContext while polling") which introduced this functionality for more information. The only way to reach bdrv_close() is via bdrv_unref() and for calling that the BlockDriverState's AioContext lock is supposed to be held. Signed-off-by: Fiona Ebner <f.ebner@proxmox.com> Message-ID: <20231019131936.414246-3-f.ebner@proxmox.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Protect bs->children with graph_lockKevin Wolf
Almost all functions that access the child links already take the graph lock now. Add locking to the remaining users and finally annotate the struct field itself as protected by the graph lock. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-22-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Mark bdrv_apply_auto_read_only() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_apply_auto_read_only() need to hold a reader lock for the graph because it calls bdrv_can_set_read_only(), which indirectly accesses the parents list of a node. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-19-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Mark bdrv_op_is_blocked() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_op_is_blocked() need to hold a reader lock for the graph because it calls bdrv_get_device_or_node_name(), which accesses the parents list of a node. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-18-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12qcow2: Mark qcow2_signal_corruption() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of qcow2_signal_corruption() need to hold a reader lock for the graph because it calls bdrv_get_node_name(), which accesses the parents list of a node. For some places, we know that they will hold the lock, but we don't have the GRAPH_RDLOCK annotations yet. In this case, add assume_graph_lock() with a FIXME comment. These places will be removed once everything is properly annotated. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-15-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Mark bdrv_get_parent_name() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_get_parent_name() need to hold a reader lock for the graph because it accesses the parents list of a node. For some places, we know that they will hold the lock, but we don't have the GRAPH_RDLOCK annotations yet. In this case, add assume_graph_lock() with a FIXME comment. These places will be removed once everything is properly annotated. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-13-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Mark bdrv_primary_child() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_primary_child() need to hold a reader lock for the graph because it accesses the children list of a node. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-12-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Mark bdrv_refresh_filename() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_refresh_filename() need to hold a reader lock for the graph because it accesses the children list of a node. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-11-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Take graph rdlock in parts of reopenKevin Wolf
Reopen isn't easy with respect to locking because many of its functions need to iterate the graph, some change it, and then you get some drains in the middle where you can't hold any locks. Therefore just documents most of the functions to be unlocked, and take locks internally before accessing the graph. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-9-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Mark drain related functions GRAPH_RDLOCKEmanuele Giuseppe Esposito
Draining recursively traverses the graph, therefore we need to make sure that also such accesses to the graph are protected by the graph rdlock. There are 3 different drain callers to consider: 1. drain in the main loop: no issue at all, rdlock is nop. 2. drain in an iothread: rdlock only works in main loop or coroutines, so disallow it. 3. drain in a coroutine (regardless of AioContext): the drain mechanism takes care of scheduling a BH in the bs->aio_context that will then take care of perform the actual draining. This is wrong, because as pointed in (2) if bs->aio_context is an iothread then rdlock won't work. Therefore change bdrv_co_yield_to_drain to schedule the BH in the main loop. Caller (2) also implies that we need to modify test-bdrv-drain.c to disallow draining in the iothreads. For some places, we know that they will hold the lock, but we don't have the GRAPH_RDLOCK annotations yet. In this case, add assume_graph_lock() with a FIXME comment. These places will be removed once everything is properly annotated. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-6-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Mark bdrv_first_blk() and bdrv_is_root_node() GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_first_blk() and bdrv_is_root_node() need to hold a reader lock for the graph. These functions are the only functions in block-backend.c that access the parent list of a node. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-5-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12block: Take graph rdlock in bdrv_inactivate_all()Kevin Wolf
The function reads the parents list, so it needs to hold the graph lock. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230929145157.45443-4-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-09-29block: Clean up local variable shadowingMarkus Armbruster
Local variables shadowing other local variables or parameters make the code needlessly hard to understand. Tracked down with -Wshadow=local. Clean up: delete inner declarations when they are actually redundant, else rename variables. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Acked-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20230921121312.1301864-7-armbru@redhat.com>
2023-09-20block: Mark bdrv_unref_child() GRAPH_WRLOCKKevin Wolf
Instead of taking the writer lock internally, require callers to already hold it when calling bdrv_unref_child(). These callers will typically already hold the graph lock once the locking work is completed, which means that they can't call functions that take it internally. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230911094620.45040-21-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-09-20block: Mark bdrv_root_unref_child() GRAPH_WRLOCKKevin Wolf
Instead of taking the writer lock internally, require callers to already hold it when calling bdrv_root_unref_child(). These callers will typically already hold the graph lock once the locking work is completed, which means that they can't call functions that take it internally. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230911094620.45040-20-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-09-20block: Take graph rdlock in bdrv_change_aio_context()Kevin Wolf
The function reads the parents list, so it needs to hold the graph lock. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-ID: <20230911094620.45040-19-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-09-20block: Take graph rdlock in bdrv_drop_intermediate()Kevin Wolf
The function reads the parents list, so it needs to hold the graph lock. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-ID: <20230911094620.45040-18-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-09-20block: Mark bdrv_parent_cb_change_media() GRAPH_RDLOCKKevin Wolf
The function reads the parents list, so it needs to hold the graph lock. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230911094620.45040-17-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-09-20block: Mark bdrv_child_perm() GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_child_perm() need to hold a reader lock for the graph because some implementations access the children list of a node. The callers of bdrv_child_perm() conveniently already hold the lock. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230911094620.45040-16-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-09-20block: Mark bdrv_get_cumulative_perm() and callers GRAPH_RDLOCKKevin Wolf
The function reads the parents list, so it needs to hold the graph lock. This happens to result in BlockDriver.bdrv_set_perm() to be called with the graph lock held. For consistency, make it the same for all of the BlockDriver callbacks for updating permissions and annotate the function pointers with GRAPH_RDLOCK_PTR. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230911094620.45040-15-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-09-20block: Mark bdrv_parent_perms_conflict() and callers GRAPH_RDLOCKKevin Wolf
The function reads the parents list, so it needs to hold the graph lock. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230911094620.45040-14-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>