Re: [bug report] btrfs: error out if btrfs_attach_transaction() fails

[Anand Jain <anand.jain@oracle.com>]

   Thanks Dan! You are right. Will fix it.

Anand


On 10/13/2017 04:39 AM, Dan Carpenter wrote:
> Hello Anand Jain,
> 
> The patch 1eea2715ca9b: "btrfs: error out if
> btrfs_attach_transaction() fails" from Sep 28, 2017, leads to the
> following static checker warning:
> 
> 	fs/btrfs/volumes.c:2502 btrfs_init_new_device()
> 	error: 'trans' dereferencing possible ERR_PTR()
> 
> fs/btrfs/volumes.c
>    2479                  ret = btrfs_relocate_sys_chunks(fs_info);
>    2480                  if (ret < 0)
>    2481                          btrfs_handle_fs_error(fs_info, ret,
>    2482                                      "Failed to relocate sys chunks after device initialization. This can be fixed using the \"btrfs balance\" command.");
>    2483                  trans = btrfs_attach_transaction(root);
>    2484                  if (IS_ERR(trans)) {
>    2485                          if (PTR_ERR(trans) == -ENOENT)
>    2486                                  return 0;
>    2487                          ret = PTR_ERR(trans);
>    2488                          goto error_sysfs;
>                                  ^^^^^^^^^^^^^^^^
> We used to have a direct return here.
> 
>    2489                  }
>    2490                  ret = btrfs_commit_transaction(trans);
>    2491          }
>    2492
>    2493          /* Update ctime/mtime for libblkid */
>    2494          update_dev_time(device_path);
>    2495          return ret;
>    2496
>    2497  error_sysfs:
>    2498          btrfs_sysfs_rm_device_link(fs_info->fs_devices, device);
>    2499  error_trans:
>    2500          if (seeding_dev)
>    2501                  sb->s_flags |= MS_RDONLY;
>    2502          btrfs_end_transaction(trans);
>                                        ^^^^^^
> But now it's dereferencing an error pointer inside this function.
> 
>    2503          rcu_string_free(device->name);
>    2504          kfree(device);
>    2505  error:
>    2506          blkdev_put(bdev, FMODE_EXCL);
>    2507          if (seeding_dev && !unlocked) {
>    2508                  mutex_unlock(&uuid_mutex);
>    2509                  up_write(&sb->s_umount);
>    2510          }
>    2511          return ret;
>    2512  }
> 
> regards,
> dan carpenter
>