[PATCH for 4.6] btrfs: disable a spurious WARN_ON in btrfs_destroy_inode.

[Adam Borowski <kilobyte@angband.pl>]

This happens a lot on real-world loads.  The issue is apparently benign,
as unsaved pending checksums are moot when the ship^Winode is going down
anyway.  Thus, no need to cause panic in users.

I've retained the warning in CONFIG_BTRFS_ASSERT builds, as this shouldn't
happen.  I've replaced the no longer helpful register+stack dump with a
printk that mentions the device affected.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
---
 fs/btrfs/inode.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2aaba58..ed78104 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9258,7 +9258,10 @@ void btrfs_destroy_inode(struct inode *inode)
 	WARN_ON(BTRFS_I(inode)->outstanding_extents);
 	WARN_ON(BTRFS_I(inode)->reserved_extents);
 	WARN_ON(BTRFS_I(inode)->delalloc_bytes);
-	WARN_ON(BTRFS_I(inode)->csum_bytes);
+#ifdef CONFIG_BTRFS_ASSERT
+	if (BTRFS_I(inode)->csum_bytes)
+		btrfs_info(root->fs_info, "btrfs_destroy_inode: leftover csum_bytes");
+#endif
 	WARN_ON(BTRFS_I(inode)->defrag_bytes);
 
 	/*
--
2.8.1