[PATCH 1/1] generic/103: increase reserved bytes for bcachefs

[Dan Robertson <dan@dlrobertson.com>]

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>
---
 tests/generic/103 | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tests/generic/103 b/tests/generic/103
index b22b0159..610f31f6 100755
--- a/tests/generic/103
+++ b/tests/generic/103
@@ -43,7 +43,15 @@ _consume_freesp()
 
 	# consume nearly all available space (leave ~512kB)
 	avail=`_get_available_space $SCRATCH_MNT`
-	filesizekb=$((avail / 1024 - 512))
+	if [ $FSTYP = "bcachefs" ]; then
+		# The bcachefs btree nodes are quite large. If the fallocate
+		# triggers a split leaf of a btree node, we'll need more
+		# than 512 kept in reserve.
+		reserve=1024
+	else
+		reserve=512
+	fi
+	filesizekb=$((avail / 1024 - reserve))
 	$XFS_IO_PROG -fc "falloc 0 ${filesizekb}k" $file
 }