From: Josef Bacik <josef@toxicpanda.com>
Date: Fri, 24 Jan 2020 09:32:51 -0500
Git-commit: ca2037fba6af039c18ae3219ff2fbacf2ca7c133
Patch-mainline: 5.7-rc1
References: bsc#1176019
Subject: [PATCH] btrfs: hold a ref on the root in btrfs_recover_log_trees

We replay the log into arbitrary fs roots, hold a ref on the root while
we're doing this.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/tree-log.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 556aa4a614f5..169270c931a9 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -6163,6 +6163,10 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
 		tmp_key.offset = (u64)-1;
 
 		wc.replay_dest = btrfs_get_fs_root(fs_info, &tmp_key, true);
+		if (!IS_ERR(wc.replay_dest)) {
+			if (!btrfs_grab_fs_root(wc.replay_dest))
+				wc.replay_dest = ERR_PTR(-ENOENT);
+		}
 		if (IS_ERR(wc.replay_dest)) {
 			ret = PTR_ERR(wc.replay_dest);
 
@@ -6219,6 +6223,7 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
 		}
 
 		wc.replay_dest->log_root = NULL;
+		btrfs_put_fs_root(wc.replay_dest);
 		free_extent_buffer(log->node);
 		free_extent_buffer(log->commit_root);
 		kfree(log);
-- 
2.26.2