Re: 3.14.23-rt20 - fs,btrfs: fix rt deadlock on extent_buffer->lock

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

* Mike Galbraith | 2014-11-02 08:31:18 [+0100]:

>--- a/fs/btrfs/ctree.c
>+++ b/fs/btrfs/ctree.c
>@@ -80,7 +80,7 @@ noinline void btrfs_clear_path_blocking(
> {
> 	int i;
> 
>-#ifdef CONFIG_DEBUG_LOCK_ALLOC
>+#if (defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_PREEMPT_RT_BASE))
> 	/* lockdep really cares that we take all of these spinlocks
> 	 * in the right order.  If any of the locks in the path are not
> 	 * currently blocking, it is going to complain.  So, make really

This is gone since commit f82c458 ("btrfs: fix lockups from
btrfs_clear_path_blocking")

>@@ -107,7 +107,7 @@ noinline void btrfs_clear_path_blocking(
> 		}
> 	}
> 
>-#ifdef CONFIG_DEBUG_LOCK_ALLOC
>+#if (defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_PREEMPT_RT_BASE))
> 	if (held)
> 		btrfs_clear_lock_blocking_rw(held, held_rw);
> #endif
>--- a/fs/btrfs/extent-tree.c
>+++ b/fs/btrfs/extent-tree.c
>@@ -6938,14 +6938,6 @@ use_block_rsv(struct btrfs_trans_handle
> 		goto again;
> 	}
> 
>-	if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
>-		static DEFINE_RATELIMIT_STATE(_rs,
>-				DEFAULT_RATELIMIT_INTERVAL * 10,
>-				/*DEFAULT_RATELIMIT_BURST*/ 1);
>-		if (__ratelimit(&_rs))
>-			WARN(1, KERN_DEBUG
>-				"BTRFS: block rsv returned %d\n", ret);
>-	}
> try_reserve:
> 	ret = reserve_metadata_bytes(root, block_rsv, blocksize,
> 				     BTRFS_RESERVE_NO_FLUSH);
>
and this look like just a warning with enabled debug that is supressed.
May I drop this patch?

Sebastian