bwlp/qemu.git/include/block/block.h, branch spice_video_codecs

include/block/block: split header into I/O and global state API

2022-03-04T17:18:25+00:00

block.h currently contains a mix of functions: some of them run under the BQL and modify the block layer graph, others are instead thread-safe and perform I/O in iothreads. Some others can only be called by either the main loop or the iothread running the AioContext (and not other iothreads), and using them in another thread would cause deadlocks, and therefore it is not ideal to define them as I/O. It is not easy to understand which function is part of which group (I/O vs GS vs "I/O or GS"), and this patch aims to clarify it. The "GS" functions need the BQL, and often use aio_context_acquire/release and/or drain to be sure they can modify the graph safely. The I/O function are instead thread safe, and can run in any AioContext. "I/O or GS" functions run instead in the main loop or in a single iothread, and use BDRV_POLL_WHILE(). By splitting the header in two files, block-io.h and block-global-state.h we have a clearer view on what needs what kind of protection. block-common.h contains common structures shared by both headers. block.h is left there for legacy and to avoid changing all includes in all c files that use the block APIs. Assertions are added in the next patch. Signed-off-by: Emanuele Giuseppe Esposito Message-Id: <20220303151616.325444-4-eesposit@redhat.com> Signed-off-by: Kevin Wolf

block: rename bdrv_invalidate_cache_all, blk_invalidate_cache and test_sync_op_invalidate_cache

2022-03-04T17:14:40+00:00

Following the bdrv_activate renaming, change also the name of the respective callers. bdrv_invalidate_cache_all -> bdrv_activate_all blk_invalidate_cache -> blk_activate test_sync_op_invalidate_cache -> test_sync_op_activate No functional change intended. Signed-off-by: Emanuele Giuseppe Esposito Reviewed-by: Juan Quintela Reviewed-by: Hanna Reitz Message-Id: <20220209105452.1694545-5-eesposit@redhat.com> Signed-off-by: Kevin Wolf

block: introduce bdrv_activate

2022-03-04T17:14:40+00:00

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 Reviewed-by: Hanna Reitz Message-Id: <20220209105452.1694545-4-eesposit@redhat.com> Signed-off-by: Kevin Wolf

block.h: remove outdated comment

2022-02-01T12:28:53+00:00

The comment "disk I/O throttling" doesn't make any sense at all any more. It was added in commit 0563e191516 to describe bdrv_io_limits_enable()/disable(), which were removed in commit 97148076, so the comment is just a forgotten leftover. Suggested-by: Kevin Wolf Signed-off-by: Emanuele Giuseppe Esposito Message-Id: <20220131125615.74612-1-eesposit@redhat.com> Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Hanna Reitz

block: drop BLK_PERM_GRAPH_MOD

2022-01-14T11:03:16+00:00

First, this permission never protected a node from being changed, as generic child-replacing functions don't check it. Second, it's a strange thing: it presents a permission of parent node to change its child. But generally, children are replaced by different mechanisms, like jobs or qmp commands, not by nodes. Graph-mod permission is hard to understand. All other permissions describe operations which done by parent node on its child: read, write, resize. Graph modification operations are something completely different. The only place where BLK_PERM_GRAPH_MOD is used as "perm" (not shared perm) is mirror_start_job, for s->target. Still modern code should use bdrv_freeze_backing_chain() to protect from graph modification, if we don't do it somewhere it may be considered as a bug. So, it's a bit risky to drop GRAPH_MOD, and analyzing of possible loss of protection is hard. But one day we should do it, let's do it now. One more bit of information is that locking the corresponding byte in file-posix doesn't make sense at all. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210902093754.2352-1-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf

block: implement bdrv_new_open_driver_opts()

2021-10-06T08:25:55+00:00

Add version of bdrv_new_open_driver() that supports QDict options. We'll use it in further commit. Simply add one more argument to bdrv_new_open_driver() is worse, as there are too many invocations of bdrv_new_open_driver() to update then. Signed-off-by: Vladimir Sementsov-Ogievskiy Suggested-by: Kevin Wolf Message-Id: <20210920115538.264372-2-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf

include/block.h: remove outdated comment

2021-10-06T08:25:55+00:00

There are a couple of errors in bdrv_drained_begin header comment: - block_job_pause does not exist anymore, it has been replaced with job_pause in b15de82867 - job_pause is automatically invoked as a .drained_begin callback (child_job_drained_begin) by the child_job BdrvChildClass struct in blockjob.c. So no additional pause should be required. Signed-off-by: Emanuele Giuseppe Esposito Message-Id: <20210903113800.59970-1-eesposit@redhat.com> Reviewed-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf

block: introduce bdrv_replace_child_bs()

2021-09-01T10:57:31+00:00

Add function to transactionally replace bs inside BdrvChild. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Max Reitz Message-Id: <20210824083856.17408-2-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz

block: Acquire AioContexts during bdrv_reopen_multiple()

2021-07-09T11:19:11+00:00

As the BlockReopenQueue can contain nodes in multiple AioContexts, only one of which may be locked when AIO_WAIT_WHILE() can be called, we can't let the caller lock the right contexts. Instead, individually lock the AioContext of a single node when iterating the queue. Reintroduce bdrv_reopen() as a wrapper for reopening a single node that drains the node and temporarily drops the AioContext lock for bdrv_reopen_multiple(). Signed-off-by: Kevin Wolf Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210708114709.206487-4-kwolf@redhat.com> Signed-off-by: Kevin Wolf

block: Add bdrv_reopen_queue_free()

2021-07-09T11:19:11+00:00

Move the code to free a BlockReopenQueue to a separate function. It will be used in a subsequent patch. [ kwolf: Also free explicit_options and options, and explicitly qobject_ref() the value when it continues to be used. This makes future memory leaks less likely. ] Signed-off-by: Alberto Garcia Signed-off-by: Kevin Wolf Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210708114709.206487-3-kwolf@redhat.com> Signed-off-by: Kevin Wolf