From: Nikolay Borisov nborisov@suse.com
[ Upstream commit beed9263f4000c48a5c48912f26576f6fa091181 ]
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@suse.com Reviewed-by: Liu Bo bo.li.liu@oracle.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- fs/btrfs/volumes.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 4006b2a1233d..bc534fafacf9 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -236,7 +236,6 @@ 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);