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block: Call .bdrv_co_create(_opts) unlocked

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These are functions that modify the graph, so they must be able to take
a writer lock. This is impossible if they already hold the reader lock.
If they need a reader lock for some of their operations, they should
take it internally.

Many of them go through blk_*(), which will always take the lock itself.
Direct calls of bdrv_*() need to take the reader lock. Note that while
locking for bdrv_co_*() calls is checked by TSA, this is not the case
for the mixed_coroutine_fns bdrv_*(). Holding the lock is still required
when they are called from coroutine context like here!

This effectively reverts 4ec8df0183, but adds some internal locking
instead.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230510203601.418015-2-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf
2023-05-10 22:35:54 +02:00
parent 41f8b63339
commit 4db7ba3b87
14 changed files with 78 additions and 70 deletions
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8
include/block/block-global-state.h
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@@ -58,14 +58,14 @@ BlockDriver *bdrv_find_protocol(const char *filename,
Error **errp);
BlockDriver *bdrv_find_format(const char *format_name);
int coroutine_fn GRAPH_RDLOCK
int coroutine_fn GRAPH_UNLOCKED
bdrv_co_create(BlockDriver *drv, const char *filename, QemuOpts *opts,
Error **errp);
int co_wrapper_bdrv_rdlock bdrv_create(BlockDriver *drv, const char *filename,
QemuOpts *opts, Error **errp);
int co_wrapper bdrv_create(BlockDriver *drv, const char *filename,
QemuOpts *opts, Error **errp);
int coroutine_fn GRAPH_RDLOCK
int coroutine_fn GRAPH_UNLOCKED
bdrv_co_create_file(const char *filename, QemuOpts *opts, Error **errp);
BlockDriverState *bdrv_new(void);