diff options
| author | Emanuele Giuseppe Esposito <eesposit@redhat.com> | 2023-01-13 21:42:04 +0100 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2023-02-01 16:52:32 +0100 |
| commit | c86422c5549c0983b4b4525b8f56a1c69dd67aa1 (patch) | |
| tree | 9791a300734a7dda8422e6a531b2d0f592a10768 /block/rbd.c | |
| parent | c057960c4e33becb22d4741156203a4b0d4a3088 (diff) | |
block: Convert bdrv_refresh_total_sectors() to co_wrapper_mixed
BlockDriver->bdrv_getlength is categorized as IO callback, and it
currently doesn't run in a coroutine. We should let it take a graph
rdlock since the callback traverses the block nodes graph, which however
is only possible in a coroutine.
Therefore turn it into a co_wrapper to move the actual function into a
coroutine where the lock can be taken.
Because now this function creates a new coroutine and polls, we need to
take the AioContext lock where it is missing, for the only reason that
internally co_wrapper calls AIO_WAIT_WHILE and it expects to release the
AioContext lock.
This is especially messy when a co_wrapper creates a coroutine and polls
in bdrv_open_driver, because this function has so many callers in so
many context that it can easily lead to deadlocks. Therefore the new
rule for bdrv_open_driver is that the caller must always hold the
AioContext lock of the given bs (except if it is a coroutine), because
the function calls bdrv_refresh_total_sectors() which is now a
co_wrapper.
Once the rwlock is ultimated and placed in every place it needs to be,
we will poll using AIO_WAIT_WHILE_UNLOCKED and remove the AioContext
lock.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230113204212.359076-7-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/rbd.c')
| -rw-r--r-- | block/rbd.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/block/rbd.c b/block/rbd.c index 6167c5e424..c127c1550d 100644 --- a/block/rbd.c +++ b/block/rbd.c @@ -1430,7 +1430,7 @@ static int coroutine_fn qemu_rbd_co_block_status(BlockDriverState *bs, return status; } -static int64_t qemu_rbd_getlength(BlockDriverState *bs) +static int64_t coroutine_fn qemu_rbd_co_getlength(BlockDriverState *bs) { BDRVRBDState *s = bs->opaque; int r; @@ -1654,7 +1654,7 @@ static BlockDriver bdrv_rbd = { .bdrv_get_info = qemu_rbd_getinfo, .bdrv_get_specific_info = qemu_rbd_get_specific_info, .create_opts = &qemu_rbd_create_opts, - .bdrv_getlength = qemu_rbd_getlength, + .bdrv_co_getlength = qemu_rbd_co_getlength, .bdrv_co_truncate = qemu_rbd_co_truncate, .protocol_name = "rbd", |