Re: ENOSPC errors during raid1 rebalance

[Hugo Mills <hugo@carfax.org.uk>]

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On Mon, Mar 03, 2014 at 05:23:43PM +0000, Mike Russo wrote:
> Hi guys -
> 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.

   This is just a guess, but you might have some large (>1GB) extents
in there that span across multiple chunks. I'd suggest running a btrfs
defrag on any particularly big files and see if that helps the situation.

   Hugo.

> Here's my vital stats: (on kernel 3.14-rc4):
> 
> root@ossy:/usr/src/btrfs-progs# /usr/src/btrfs-progs/btrfs fi show
> Label: MyBook  uuid: c99cbefb-6a56-41e2-8f99-19f8b5f67884
>         Total devices 2 FS bytes used 1.09TiB
>         devid    1 size 1.82TiB used 1.12TiB path /dev/sdc1
>         devid    2 size 1.82TiB used 1.05TiB path /dev/sdd1
> 
> Btrfs v3.12
> root@ossy:/usr/src/btrfs-progs# /usr/src/btrfs-progs/btrfs fi df /mymedia
> Data, RAID1: total=1.04TiB, used=1.03TiB
> Data, single: total=70.00GiB, used=64.98GiB
> System, RAID1: total=32.00MiB, used=160.00KiB
> Metadata, RAID1: total=2.00GiB, used=1.33GiB
> 
> 
> I've already done a -dusage=0 and -dusage=5 balance and that cleans up anything that gets left around when these 14 blocks fail get moved.    When mounting with enospc_debug I get messages like this for each block with the problem:
> 
> 
> Mar  3 11:58:16 ossy kernel: [52724.423024] BTRFS: block group 935262683136 has 5368709120 bytes, 5321801728 used 0 pinned 0 reserved [readonly]
> Mar  3 11:58:16 ossy kernel: [52724.423025] BTRFS info (device sdd1): block group has cluster?: no
> Mar  3 11:58:16 ossy kernel: [52724.423026] BTRFS info (device sdd1): 0 blocks of free space at or bigger than bytes is
> Mar  3 11:58:16 ossy kernel: [52724.423027] BTRFS: block group 942778875904 has 5368709120 bytes, 5309296640 used 0 pinned 0 reserved [readonly]
> Mar  3 11:58:16 ossy kernel: [52724.423028] BTRFS info (device sdd1): block group has cluster?: no
> Mar  3 11:58:16 ossy kernel: [52724.423029] BTRFS info (device sdd1): 0 blocks of free space at or bigger than bytes is
> 
> I don't have the space to reformat and if this is a genuine bug I'm sure you guys want to fix it too. What else can I do to resolve or help? 
> 
> 
> Sincerely,
> 
> Michael Russo, Systems Engineer
> PaperSolve, Inc.
> 268 Watchogue Road
> Staten Island, NY 10314
> 

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
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