From: Josef Bacik <josef@toxicpanda.com>
Date: Wed, 20 Nov 2019 19:46:11 +0000 (-0800)
Subject: btrfs: hold a ref on the root in merge_reloc_roots
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1ca575ad7215213f005a96814a01f3d231647f45;p=linux

btrfs: hold a ref on the root in merge_reloc_roots

We look up the corresponding root for the reloc root, we need to hold a
ref while we're messing with it.

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

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 19d69ce41f06..dfd3d9053301 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2505,10 +2505,13 @@ again:
 		if (btrfs_root_refs(&reloc_root->root_item) > 0) {
 			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);
 
 			ret = merge_reloc_root(rc, root);
+			btrfs_put_fs_root(root);
 			if (ret) {
 				if (list_empty(&reloc_root->root_list))
 					list_add_tail(&reloc_root->root_list,