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/blklogwrites.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/blklogwrites.c')
| -rw-r--r-- | block/blklogwrites.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/block/blklogwrites.c b/block/blklogwrites.c index a5bf767184..b00b8a6dd0 100644 --- a/block/blklogwrites.c +++ b/block/blklogwrites.c @@ -267,9 +267,9 @@ static void blk_log_writes_close(BlockDriverState *bs) s->log_file = NULL; } -static int64_t blk_log_writes_getlength(BlockDriverState *bs) +static int64_t coroutine_fn blk_log_writes_co_getlength(BlockDriverState *bs) { - return bdrv_getlength(bs->file->bs); + return bdrv_co_getlength(bs->file->bs); } static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c, @@ -498,7 +498,7 @@ static BlockDriver bdrv_blk_log_writes = { .bdrv_open = blk_log_writes_open, .bdrv_close = blk_log_writes_close, - .bdrv_getlength = blk_log_writes_getlength, + .bdrv_co_getlength = blk_log_writes_co_getlength, .bdrv_child_perm = blk_log_writes_child_perm, .bdrv_refresh_limits = blk_log_writes_refresh_limits, |