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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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6
block/qed.c
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@ -630,8 +630,8 @@ static void bdrv_qed_close(BlockDriverState *bs)
qemu_vfree(s->l1_table);
}
static int coroutine_fn bdrv_qed_co_create(BlockdevCreateOptions *opts,
Error **errp)
static int coroutine_fn GRAPH_UNLOCKED
bdrv_qed_co_create(BlockdevCreateOptions *opts, Error **errp)
{
BlockdevCreateOptionsQed *qed_opts;
BlockBackend *blk = NULL;
@ -751,7 +751,7 @@ out:
return ret;
}
static int coroutine_fn GRAPH_RDLOCK
static int coroutine_fn GRAPH_UNLOCKED
bdrv_qed_co_create_opts(BlockDriver *drv, const char *filename,
QemuOpts *opts, Error **errp)
{