diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 920df7585b0d..5e75a4e3a5be 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -732,6 +732,42 @@ const u8 *btrfs_sb_fsid_ptr(const struct btrfs_super_block *sb) return has_metadata_uuid ? sb->metadata_uuid : sb->fsid; } +static bool is_same_device(struct btrfs_device *device, const char *new_path) +{ + struct path old = { .mnt = NULL, .dentry = NULL }; + struct path new = { .mnt = NULL, .dentry = NULL }; + char *old_path = NULL; + bool is_same = false; + int ret; + + if (!device->name) + goto out; + + old_path = kzalloc(PATH_MAX, GFP_NOFS); + if (!old_path) + goto out; + + rcu_read_lock(); + ret = strscpy(old_path, rcu_str_deref(device->name), PATH_MAX); + rcu_read_unlock(); + if (ret < 0) + goto out; + + ret = kern_path(old_path, LOOKUP_FOLLOW, &old); + if (ret) + goto out; + ret = kern_path(new_path, LOOKUP_FOLLOW, &new); + if (ret) + goto out; + if (path_equal(&old, &new)) + is_same = true; +out: + kfree(old_path); + path_put(&old); + path_put(&new); + return is_same; +} + /* * Add new device to list of registered devices * @@ -852,7 +888,7 @@ static noinline struct btrfs_device *device_list_add(const char *path, MAJOR(path_devt), MINOR(path_devt), current->comm, task_pid_nr(current)); - } else if (!device->name || strcmp(device->name->str, path)) { + } else if (!device->name || !is_same_device(device, path)) { /* * When FS is already mounted. * 1. If you are here and if the device->name is NULL that