On 06/21/2017 05:08 PM, Jeff Mahoney wrote:
On 6/21/17 4:31 PM, Chris Mason wrote:
On 06/21/2017 04:14 PM, Jeff Mahoney wrote:
On 6/14/17 11:44 AM, je...@suse.com wrote:
From: Jeff Mahoney <je...@suse.com>
In a heavy write scenario, we can end up with a large number of pinned
bytes. This can translate into (very) premature ENOSPC because pinned
bytes must be accounted for when allowing a reservation but aren't
accounted for when deciding whether to create a new chunk.
This patch adds the accounting to should_alloc_chunk so that we can
create the chunk.
Signed-off-by: Jeff Mahoney <je...@suse.com>
---
fs/btrfs/extent-tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index cb0b924..d027807 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4389,7 +4389,7 @@ static int should_alloc_chunk(struct
btrfs_fs_info *fs_info,
{
struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
- u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
+ u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved +
sinfo->bytes_pinned + sinfo->bytes_may_use;
u64 thresh;
if (force == CHUNK_ALLOC_FORCE)
Ignore this patch. It certainly allocates chunks more aggressively, but
it means we end up with a ton of metadata chunks even when we don't have
much metadata.
Josef and I pushed this needle back and forth a bunch of times in the
early days. I still think we can allocate a few more chunks than we do
now...
I agree. This patch was to fix an issue that we are seeing during
installation. It'd stop with ENOSPC with >50GB completely unallocated.
The patch passed the test cases that were failing before but now it's
failing differently. I was worried this pattern might be the end result:
Data,single: Size:4.00GiB, Used:3.32GiB
/dev/vde 4.00GiB
Metadata,DUP: Size:20.00GiB, Used:204.12MiB
/dev/vde 40.00GiB
System,DUP: Size:8.00MiB, Used:16.00KiB
/dev/vde 16.00MiB
This is on a fresh file system with just "cp /usr /mnt" executed.
I'm looking into it a bit more now.
Does this failure still happen with Omar's ENOSPC fix (commit:
70e7af244f24c94604ef6eca32ad297632018583)
-chris
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