From: Josef Bacik <josef@toxicpanda.com>
Date: Fri, 24 Jan 2020 09:32:33 -0500
Git-commit: 3ca35e839e949811c7e35b7ef786de225a1c5008
Patch-mainline: 5.7-rc1
References: bsc#1176019
Subject: [PATCH] btrfs: hold a ref on the root in search_ioctl

We lookup a arbitrary fs root, we need to hold a ref on that root.  If
we're using our own inodes root then grab a ref on that as well to make
the cleanup easier.

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/ioctl.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0e524f3eaa9f..b173bb6915d9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2180,7 +2180,7 @@ static noinline int search_ioctl(struct inode *inode,
 
 	if (sk->tree_id == 0) {
 		/* search the root of the inode that was passed */
-		root = BTRFS_I(inode)->root;
+		root = btrfs_grab_fs_root(BTRFS_I(inode)->root);
 	} else {
 		key.objectid = sk->tree_id;
 		key.type = BTRFS_ROOT_ITEM_KEY;
@@ -2190,6 +2190,10 @@ static noinline int search_ioctl(struct inode *inode,
 			btrfs_free_path(path);
 			return PTR_ERR(root);
 		}
+		if (!btrfs_grab_fs_root(root)) {
+			btrfs_free_path(path);
+			return -ENOENT;
+		}
 	}
 
 	key.objectid = sk->min_objectid;
@@ -2214,6 +2218,7 @@ static noinline int search_ioctl(struct inode *inode,
 		ret = 0;
 err:
 	sk->nr_items = num_found;
+	btrfs_put_fs_root(root);
 	btrfs_free_path(path);
 	return ret;
 }
-- 
2.26.2