From: Josef Bacik <josef@toxicpanda.com>
Date: Wed, 20 Nov 2019 19:45:06 +0000 (-0800)
Subject: btrfs: hold a ref on the root in prepare_to_merge
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5a2cfd6d103e863000edd7842856f80d42167359;p=linux

btrfs: hold a ref on the root in prepare_to_merge

We look up the reloc roots corresponding root, we need to hold a ref on
that root.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 473bbbd58d31..19d69ce41f06 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2433,6 +2433,8 @@ again:
 		list_del_init(&reloc_root->root_list);
 
 		root = read_fs_root(fs_info, reloc_root->root_key.offset);
+		if (!btrfs_grab_fs_root(root))
+			BUG();
 		BUG_ON(IS_ERR(root));
 		BUG_ON(root->reloc_root != reloc_root);
 
@@ -2445,6 +2447,7 @@ again:
 		btrfs_update_reloc_root(trans, root);
 
 		list_add(&reloc_root->root_list, &reloc_roots);
+		btrfs_put_fs_root(root);
 	}
 
 	list_splice(&reloc_roots, &rc->reloc_roots);