Btrfs: don't look at bio flags after submit_bio
After callling submit_bio, the bio can be freed at any time. The
btrfs submission thread helper was checking the bio flags too late,
which might not give the correct answer.
When CONFIG_DEBUG_PAGE_ALLOC is turned on, it can lead to oopsen.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 4053fc4..9df8e3f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -256,13 +256,13 @@
wake_up(&fs_info->async_submit_wait);
BUG_ON(atomic_read(&cur->bi_cnt) == 0);
- submit_bio(cur->bi_rw, cur);
- num_run++;
- batch_run++;
if (bio_rw_flagged(cur, BIO_RW_SYNCIO))
num_sync_run++;
+ submit_bio(cur->bi_rw, cur);
+ num_run++;
+ batch_run++;
if (need_resched()) {
if (num_sync_run) {
blk_run_backing_dev(bdi, NULL);