From: Josef Bacik <josef@toxicpanda.com>
Date: Wed, 20 Nov 2019 15:56:19 +0000 (-0800)
Subject: btrfs: hold a root ref in btrfs_get_dentry
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a2208f19c8a85f41edaaf8536a05780a773b3d8b;p=linux

btrfs: hold a root ref in btrfs_get_dentry

Looking up the inode we need to search the root, make sure we hold a
reference on that root while we're doing the lookup.

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

diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 08cd8c4a02a5..eba6c6d27bad 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -82,12 +82,17 @@ static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
 		err = PTR_ERR(root);
 		goto fail;
 	}
+	if (!btrfs_grab_fs_root(root)) {
+		err = -ENOENT;
+		goto fail;
+	}
 
 	key.objectid = objectid;
 	key.type = BTRFS_INODE_ITEM_KEY;
 	key.offset = 0;
 
 	inode = btrfs_iget(sb, &key, root);
+	btrfs_put_fs_root(root);
 	if (IS_ERR(inode)) {
 		err = PTR_ERR(inode);
 		goto fail;