Commit e0ae99941423 ("btrfs: preallocate device flush bio") reworked
the way the flush bio is allocated and used. Concretely it allocates
the bio in __alloc_device and then re-uses it multiple times with a
very simple endio routine that just calls complete() without consuming
a reference. Allocated bios by default come with a ref count of 1,
which is then consumed by the endio routine (or not, in which case they
should be bio_put by the caller). The way the impleementation works now
is that the flush bio has a refcount of 2 and we only ever bio_put it
once, leaving it to hang indefinitely. Fix this by removing the extra
bio_get in __alloc_device.
Fixes: e0ae99941423 ("btrfs: preallocate device flush bio")
Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
---
fs/btrfs/volumes.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 132966950f5f..3690822d469a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -312,7 +312,6 @@ static struct btrfs_device *__alloc_device(void)
kfree(dev);
return ERR_PTR(-ENOMEM);
}
- bio_get(dev->flush_bio);
INIT_LIST_HEAD(&dev->dev_list);
INIT_LIST_HEAD(&dev->dev_alloc_list);
--
2.7.4
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