Btrfs: reset cluster's max_size when creating bitmap

The field that indicates the size of the largest contiguous chunk of
free space in the cluster is not initialized when setting up bitmaps,
it's only increased when we find a larger contiguous chunk.  We end up
retaining a larger value than appropriate for highly-fragmented
clusters, which may cause pointless searches for large contiguous
groups, and even cause clusters that do not meet the density
requirements to be set up.

Signed-off-by: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index ff179b1e7423dab78113066d375b5b03bc2f50c0..ec23d43d0c357870a14bf6e79a0ce5baeb93a43d 100644 (file)
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2320,6 +2320,7 @@ again:
 
        if (!found) {
                start = i;
+               cluster->max_size = 0;
                found = true;
        }