From: Josef Bacik <josef@toxicpanda.com>
Date: Fri, 12 Mar 2021 15:24:56 -0500
Subject: btrfs: convert some BUG_ON()'s to ASSERT()'s in do_relocation
Git-commit: ffe30dd892ad37f1193ae639ce7e2ad142a62721
Patch-mainline: v5.13-rc1
References: bsc#1187833

A few of these are checking for correctness, and won't be triggered by
corrupted file systems, so convert them to ASSERT() instead of BUG_ON()
and add a comment explaining their existence.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/relocation.c |   18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2865,7 +2865,11 @@ static int do_relocation(struct btrfs_tr
 	int slot;
 	int ret = 0;
 
-	BUG_ON(lowest && node->eb);
+	/*
+	 * If we are lowest then this is the first time we're processing this
+	 * block, and thus shouldn't have an eb associated with it yet.
+	 */
+	ASSERT(!lowest || !node->eb);
 
 	path->lowest_level = node->level + 1;
 	rc->backref_cache.path[node->level] = node;
@@ -2961,7 +2965,11 @@ static int do_relocation(struct btrfs_tr
 			free_extent_buffer(eb);
 			if (ret < 0)
 				goto next;
-			BUG_ON(node->eb != eb);
+			/*
+			 * We've just COWed this block, it should have updated
+			 * the correct backref node entry.
+			 */
+			ASSERT(node->eb == eb);
 		} else {
 			btrfs_set_node_blockptr(upper->eb, slot,
 						node->eb->start);
@@ -2997,7 +3005,11 @@ next:
 	}
 
 	path->lowest_level = 0;
-	BUG_ON(ret == -ENOSPC);
+	/*
+	 * We should have allocated all of our space in the block rsv and thus
+	 * shouldn't ENOSPC.
+	 */
+	ASSERT(ret != -ENOSPC);
 	return ret;
 }