From: Josef Bacik <josef@toxicpanda.com>
Date: Thu, 11 Oct 2018 15:54:22 -0400
Subject: btrfs: fix insert_reserved error handling
Git-commit: 80ee54bfe8a3850015585ebc84e8d207fcae6831
Patch-mainline: v4.20-rc1
References: bsc##1165949

We were not handling the reserved byte accounting properly for data
references.  Metadata was fine, if it errored out the error paths would
free the bytes_reserved count and pin the extent, but it even missed one
of the error cases.  So instead move this handling up into
run_one_delayed_ref so we are sure that both cases are properly cleaned
up in case of a transaction abort.

CC: stable@vger.kernel.org # 4.18+
Reviewed-by: Nikolay Borisov <nborisov@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/extent-tree.c |   10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2518,6 +2518,9 @@ static int run_one_delayed_ref(struct bt
 					   insert_reserved);
 	else
 		BUG();
+	if (ret && insert_reserved)
+		btrfs_pin_extent(trans->fs_info, node->bytenr,
+				 node->num_bytes, 1);
 	return ret;
 }
 
@@ -8182,19 +8185,14 @@ static int alloc_reserved_tree_block(str
 		size += sizeof(*block_info);
 
 	path = btrfs_alloc_path();
-	if (!path) {
-		btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
-						   fs_info->nodesize);
+	if (!path)
 		return -ENOMEM;
-	}
 
 	path->leave_spinning = 1;
 	ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
 				      ins, size);
 	if (ret) {
 		btrfs_free_path(path);
-		btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
-						   fs_info->nodesize);
 		return ret;
 	}