Kline, Matthew
2014-Nov-12 18:48 UTC
btrfs balance fails with no space errors (despite having plenty)
Hi all, Yesterday I converted my ext4 root and home partitions on my home machine to btrfs using btrfs-convert. After confirming that everything went well, I followed the wiki instructions to nuke the 'ext2_saved" subvolume, then defraggad and rebalanced. Everything went according to plan on my root partition, but my home partition claimed to have run out of space when rebalancing. I did some digging and tried the following to resolve the problem, but to no avail. So far I have: - Made sure I deleted the subvolume (a common cause of this problem). `sudo btrfs subvolume list -a /home` exits with no output. - Made sure I defragged the newly converted btrfs partition before attempting to rebalance it. - Made sure that I actually have space on the partition. It is only about 60% full - see sdb1 below: ~ % sudo btrfs fi show Label: none uuid: 3a154348-9bd4-4c3f-aaf8-e9446d3797db Total devices 1 FS bytes used 9.49GiB devid 1 size 87.47GiB used 11.03GiB path /dev/sda3 Label: none uuid: cc90ee50-bbda-46d6-a7e6-fe1c8578d75b Total devices 1 FS bytes used 124.98GiB devid 1 size 200.00GiB used 127.03GiB path /dev/sdb1 - Made sure I have metadata space (as suggested on the problem FAQ): ~ % sudo btrfs fi df /home Data, single: total=126.00GiB, used=124.58GiB System, single: total=32.00MiB, used=20.00KiB Metadata, single: total=1.00GiB, used=404.27MiB GlobalReserve, single: total=136.00MiB, used=0.00B - Ran partial rebalances using the `-dusage` flag (as suggested on the problem FAQ), which successfully balanced a handful of blocks. - Checked the system log - nothing interesting comes up. btrfs happily chugs along with "found xxx extents" and "relocating block group xxxxx flags 1" messages before unceremoniously ending with "7 enospc errors during balance". In spite of all of this, a full rebalance still fails when it's about 95% done. I'm at a complete loss as to what could be causing it - I know that it's not completely necessary (especially with a single drive), and `btrfs scrub` finds no errors with the file system, but the wiki gives the impression that it's a good idea after you convert from ext. Is there something I'm missing? Best, Matt Kline Other obligatory info: I'm on Arch Linux using btrfs 3.17.1. uname -a is Linux kline-arch 3.17.2-1-ARCH #1 SMP PREEMPT Thu Oct 30 20:49:39 CET 2014 x86_64 GNU/Linux -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at vger.kernel.org/majordomo-info.html