generic/456: document the fix commit

Add a link to Ted's post with more details about the bug
and the fix.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

diff --git a/tests/generic/456 b/tests/generic/456
index 8debd3f2d2400da38cc023befdddd33a3676bf63..ed3cacc2c9b3286a68396a5d5f0dfdb626e5deb8 100755 (executable)
--- a/tests/generic/456
+++ b/tests/generic/456
@@ -4,6 +4,9 @@
 # This test is motivated by a bug found in ext4 during random crash
 # consistency tests.
 #
+# Fixed by commit 51e3ae81ec58 ("ext4: fix interaction between i_size,
+# fallocate, and delalloc after a crash")
+#
 #-----------------------------------------------------------------------
 # Copyright (C) 2017 CTERA Networks. All Rights Reserved.
 # Author: Amir Goldstein <amir73il@gmail.com>
@@ -58,6 +61,8 @@ _require_metadata_journaling $SCRATCH_DEV
 _init_flakey
 _mount_flakey
 
+# See this post for reverse engineering of this auto generated test:
+# https://marc.info/?l=linux-ext4&m=151137380830381&w=2
 fsxops=$tmp.fsxops
 cat <<EOF > $fsxops
 write 0x137dd 0xdc69 0x0