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...

-chris

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