Btrfs: account for large extents with enospc
On our gluster boxes we stream large tar balls of backups onto our fses. With
160gb of ram this means we get really large contiguous ranges of dirty data, but
the way our ENOSPC stuff works is that as long as it's contiguous we only hold
metadata reservation for one extent. The problem is we limit our extents to
128mb, so we'll end up with at least 800 extents so our enospc accounting is
quite a bit lower than what we need. To keep track of this make sure we
increase outstanding_extents for every multiple of the max extent size so we can
be sure to have enough reserved metadata space. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d3562dd..b3dd55f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -198,6 +198,8 @@
#define BTRFS_DIRTY_METADATA_THRESH (32 * 1024 * 1024)
+#define BTRFS_MAX_EXTENT_SIZE (128 * 1024 * 1024)
+
/*
* The key defines the order in the tree, and so it also defines (optimal)
* block layout.