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authorStefan Behrens <sbehrens@giantdisaster.de>2013-05-07 17:28:03 +0000
committerJosef Bacik <jbacik@fusionio.com>2013-05-17 21:40:16 -0400
commit49688107527a24b0ed3780576257a1225902180b (patch)
tree099d5b0d92cb201c4f32c19f00d87aeff7eca6a7 /fs
parentb1c79e0947e0c190f865e2eb7b84a0fea0021cec (diff)
downloadlinux-49688107527a24b0ed3780576257a1225902180b.tar.gz
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/dev-replace.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 7ba7b3900cb8..65241f32d3f8 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -313,6 +313,11 @@ int btrfs_dev_replace_start(struct btrfs_root *root,
 	struct btrfs_device *tgt_device = NULL;
 	struct btrfs_device *src_device = NULL;
 
+	if (btrfs_fs_incompat(fs_info, RAID56)) {
+		pr_warn("btrfs: dev_replace cannot yet handle RAID5/RAID6\n");
+		return -EINVAL;
+	}
+
 	switch (args->start.cont_reading_from_srcdev_mode) {
 	case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS:
 	case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID: