Mike Russo posted on Mon, 03 Mar 2014 17:23:43 +0000 as excerpted: > I'm trying to convert a disk from single (/dev/sdc1) to RAID1 > (dev/sdd1), and the filesystem was previously ext4 but the conversion > seemed to go just fine, and I have no snapshots. System and metadata > convert, and almost all my data converts, but there are 70 stubborn GB > (14 blocks of 5GB each) that refuse to convert and I get ENOSPC errors > when trying to reallocate them.
While I created entirely new btrfs filesystems here and copied everything over rather than converting so I've not had personal experience with the conversion process... The wiki[1] says[2] that while the conversion process uses the same data blocks for both ext3/4 and btrfs, it duplicates the ext3/4 metadata, creating a new btrfs copy (or two, for default metadata dup mode), leaving the original ext3/4 copy untouched. Btrfs modifications are then done using standard btrfs COW (copy-on-write) methods, so the ext3/4 data, while originally shared, remains untouched as well. That allows rollback if desired, but does tie up some some space with the automatically created btrfs "snapshot" that contains the ext3/4 metadata and untouched data. While you say you have no snapshots, it's unclear whether you mean none that you've created /since/ the conversion, but you didn't delete that original snapshot so still have it, or whether you deleted that automatically created btrfs snapshot of the old ext3/4 filesystem and simply didn't specifically mention it. I'm guessing that it's the former, and that btrfs is refusing to balance/ restripe that old ext3/4 snapshot albeit with a very confusing ENOSPC error message, since it'd kill the old ext3/4 filesystem and you could no longer rollback. If that's the case, the page at [2] explains how you get rid of the old ext3/4 snapshot once you're sure you won't be rolling back and thus no longer need it. With a bit of luck, that's all you need to do, and after deleting that, you can finish your balance/restripe. =:^) If you've already btrfs subvol delete-ed the ext2_saved subvolume, or if you hadn't but doing so doesn't solve the problem, well, I went for the low-hanging-fruit solution but obviously that wasn't it. =:^( Hopefully someone else can help further. --- [1] https://btrfs.wiki.kernel.org Bookmark it! =:^) [2] https://btrfs.wiki.kernel.org/index.php/Conversion_from_Ext3 -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
