generic/103: increase reserved bytes for bcachefs

The bcachefs btree nodes are quite large. If we only reserve 512 bytes
we hit an intermittent failure where the fallocate that is intented to
fill the available space triggers a btree node split and the exente update
is interrupted. The retry of the extent update will fail because the
new amount of available space is less than that of the request.

Signed-off-by: Dan Robertson <dan@dlrobertson.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/tests/generic/103 b/tests/generic/103
index fd650ec9..329818eb 100755
--- a/tests/generic/103
+++ b/tests/generic/103
@@ -38,6 +38,13 @@ _consume_freesp()
 		left=$((left + avail / 1024000))
 	fi
 
+	if [ $FSTYP = "bcachefs" ]; then
+		# The bcachefs btree nodes are quite large. If the fallocate
+		# triggers a split leaf of a btree node, we'll need more
+		# than 512 kept in reserve.
+		left=1024
+	fi
+
 	filesizekb=$((avail / 1024 - $left))
 	$XFS_IO_PROG -fc "falloc 0 ${filesizekb}k" $file
 }