Re: Still getting a lot of -28 (ENOSPC?) errors during balance

[Josef Bacik <jbacik@fusionio.com>]

On Tue, Apr 02, 2013 at 02:04:52AM -0600, Roman Mamedov wrote:
> Hello,
> 
> With kernel 3.7.10 patched with "Btrfs: limit the global reserve to 512mb".
> (the problem was occuring also without this patch, but seemed to be even worse).
> 
> At the start of balance:
> 
> Data: total=31.85GB, used=9.96GB
> System: total=4.00MB, used=16.00KB
> Metadata: total=1.01GB, used=696.17MB
> 
> "btrfs balance start -musage=5 -dusage=5" is going on for about 50 minutes
> 
> Current situation:
> 
> Balance on '/mnt/r1/' is running
> 1 out of about 2 chunks balanced (20 considered),  50% left
> 
> Data: total=30.85GB, used=10.04GB
> System: total=4.00MB, used=16.00KB
> Metadata: total=1.01GB, used=851.69MB
> 
> And a constant stream of these in dmesg:
> 

Can you try this out and see if it helps?  Thanks,

Josef

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 0d89ff0..9830e86 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2548,6 +2548,13 @@ static int do_relocation(struct btrfs_trans_handle *trans,
 	list_for_each_entry(edge, &node->upper, list[LOWER]) {
 		cond_resched();
 
+		ret = btrfs_block_rsv_refill(rc->extent_root, rc->block_rsv,
+					     rc->extent_root->leafsize,
+					     BTRFS_RESERVE_FLUSH_ALL);
+		if (ret) {
+			err = ret;
+			break;
+		}
 		upper = edge->node[UPPER];
 		root = select_reloc_root(trans, rc, upper, edges, &nr);
 		BUG_ON(!root);