Btrfs: don't allow device replace on RAID5/RAID6
authorStefan Behrens <sbehrens@giantdisaster.de>
Tue, 7 May 2013 17:28:03 +0000 (17:28 +0000)
committerJosef Bacik <jbacik@fusionio.com>
Sat, 18 May 2013 01:40:16 +0000 (21:40 -0400)
commit49688107527a24b0ed3780576257a1225902180b
tree099d5b0d92cb201c4f32c19f00d87aeff7eca6a7
parentb1c79e0947e0c190f865e2eb7b84a0fea0021cec
Btrfs: don't allow device replace on RAID5/RAID6

This is not yet supported and causes crashes. One sad user reported
that it destroyed his filesystem.

One failure is in __btrfs_map_block+0xc1f calling kmalloc(0).

0x5f21f is in __btrfs_map_block (fs/btrfs/volumes.c:4923).
4918                            num_stripes = map->num_stripes;
4919                            max_errors = nr_parity_stripes(map);
4920
4921                            raid_map = kmalloc(sizeof(u64) * num_stripes,
4922                                               GFP_NOFS);
4923                            if (!raid_map) {
4924                                    ret = -ENOMEM;
4925                                    goto out;
4926                            }
4927

There might be more issues. Until this is really tested, don't allow
users to start the procedure on RAID5/RAID6 filesystems.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
fs/btrfs/dev-replace.c