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/preallocate.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/preallocate.c')
| -rw-r--r-- | block/preallocate.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/block/preallocate.c b/block/preallocate.c index a51fc08515..c9881942a3 100644 --- a/block/preallocate.c +++ b/block/preallocate.c @@ -442,7 +442,7 @@ static int coroutine_fn preallocate_co_flush(BlockDriverState *bs) return bdrv_co_flush(bs->file->bs); } -static int64_t preallocate_getlength(BlockDriverState *bs) +static int64_t coroutine_fn preallocate_co_getlength(BlockDriverState *bs) { int64_t ret; BDRVPreallocateState *s = bs->opaque; @@ -451,7 +451,7 @@ static int64_t preallocate_getlength(BlockDriverState *bs) return s->data_end; } - ret = bdrv_getlength(bs->file->bs); + ret = bdrv_co_getlength(bs->file->bs); if (has_prealloc_perms(bs)) { s->file_end = s->zero_start = s->data_end = ret; @@ -537,9 +537,9 @@ BlockDriver bdrv_preallocate_filter = { .format_name = "preallocate", .instance_size = sizeof(BDRVPreallocateState), - .bdrv_getlength = preallocate_getlength, - .bdrv_open = preallocate_open, - .bdrv_close = preallocate_close, + .bdrv_co_getlength = preallocate_co_getlength, + .bdrv_open = preallocate_open, + .bdrv_close = preallocate_close, .bdrv_reopen_prepare = preallocate_reopen_prepare, .bdrv_reopen_commit = preallocate_reopen_commit, |