Merge branch 'ext/anand/harden-dev-rename' into for-next-next-v4.20-20181106

1 files changed, 23 insertions, 0 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 1e7f99d4b1cf..0fb123bb53e2 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -850,6 +850,29 @@ static noinline struct btrfs_device *device_list_add(const char *path,
 			return ERR_PTR(-EEXIST);
 		}
 
+		/*
+		 * we are going to replace the device path, make sure its the
+		 * same device if the device mounted
+		 */
+		if (device->bdev) {
+			struct block_device *path_bdev;
+
+			path_bdev = lookup_bdev(path);
+			if (IS_ERR(path_bdev)) {
+				mutex_unlock(&fs_devices->device_list_mutex);
+				return ERR_CAST(path_bdev);
+			}
+
+			if (device->bdev != path_bdev) {
+				bdput(path_bdev);
+				mutex_unlock(&fs_devices->device_list_mutex);
+				return ERR_PTR(-EEXIST);
+			}
+			bdput(path_bdev);
+			pr_info("BTRFS: device fsid:devid %pU:%llu old path:%s new path:%s\n",
+				disk_super->fsid, devid, rcu_str_deref(device->name), path);
+		}
+
 		name = rcu_string_strdup(path, GFP_NOFS);
 		if (!name) {
 			mutex_unlock(&fs_devices->device_list_mutex);