btrfs: clone a hole post eof when using NO_HOLES feature

Test that when using the NO_HOLES feature, if we truncate down a
file, clone a file range covering only a hole into an offset beyond
the current file size, and then fsync the file, after a power
failure we get the expected file content and we do not get stale
data corresponding to file extents that existed before truncating
the file.

This currently fails on btrfs and is fixed by commit 3660d0bcdb82
("btrfs: fix stale data exposure after cloning a hole with NO_HOLES
enabled")

[Eryu: add the commit id of the patch fixing the bug]

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

tests/btrfs/231

@@ -0,0 +1,87 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2021 SUSE Linux Products GmbH. All Rights Reserved.
+#
+# FSQA Test No. 231
+#
+# Test that when using the NO_HOLES feature, if we truncate down a file, clone a
+# file range covering only a hole into an offset beyond the current file size,
+# and then fsync the file, after a power failure we get the expected file content
+# and we do not get stale data corresponding to file extents that existed before
+# truncating the file.
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	_cleanup_flakey
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/dmflakey
+
+# real QA test starts here
+_supported_fs btrfs
+_require_scratch
+_require_btrfs_fs_feature "no_holes"
+_require_btrfs_mkfs_feature "no-holes"
+_require_dm_target flakey
+
+rm -f $seqres.full
+
+_scratch_mkfs -O no-holes >>$seqres.full 2>&1
+_require_metadata_journaling $SCRATCH_DEV
+_init_flakey
+_mount_flakey
+
+# Create our test file with 3 extents of 256K and a 256K hole at offset 256K.
+# The file has a size of 1280K.
+$XFS_IO_PROG -f -s \
+	     -c "pwrite -S 0xab -b 256K 0 256K" \
+	     -c "pwrite -S 0xcd -b 256K 512K 256K" \
+	     -c "pwrite -S 0xef -b 256K 768K 256K" \
+	     -c "pwrite -S 0x73 -b 256K 1024K 256K" \
+	     $SCRATCH_MNT/foobar | _filter_xfs_io
+
+# Make sure it's durably persisted. We want the last committed super block to
+# point to this particular file extent layout.
+sync
+
+# Now truncate our file to a smaller size, falling within a position of the
+# second extent. This sets the full sync runtime flag on the inode.
+# Then fsync the file to log it and clear the full sync flag from the inode.
+# The third extent is no longer part of the file and therefore it is not logged.
+$XFS_IO_PROG -c "truncate 800K" -c "fsync" $SCRATCH_MNT/foobar
+
+# Now do a clone operation that only clones the hole and sets back the file size
+# to match the size it had before the truncate operation (1280K).
+$XFS_IO_PROG \
+	-c "reflink $SCRATCH_MNT/foobar 256K 1024K 256K" \
+	-c "fsync" \
+	$SCRATCH_MNT/foobar | _filter_xfs_io
+
+echo "File data before power failure:"
+od -A d -t x1 $SCRATCH_MNT/foobar
+
+# Simulate a power failure and then mount again the filesystem to replay the log
+# tree.
+_flakey_drop_and_remount
+
+# This should match what we got before the power failure. The range from 1024K
+# to 1280K should be a hole and not point to an extent full of bytes with a
+# value of 0x73.
+echo "File data after power failure:"
+od -A d -t x1 $SCRATCH_MNT/foobar
+
+_unmount_flakey
+status=0
+exit

tests/btrfs/231.out

@@ -0,0 +1,35 @@
+QA output created by 231
+wrote 262144/262144 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 262144/262144 bytes at offset 524288
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 262144/262144 bytes at offset 786432
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 262144/262144 bytes at offset 1048576
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+linked 262144/262144 bytes at offset 1048576
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+File data before power failure:
+0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
+*
+0262144 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+*
+0524288 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd
+*
+0786432 ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef
+*
+0819200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+*
+1310720
+File data after power failure:
+0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
+*
+0262144 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+*
+0524288 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd
+*
+0786432 ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef
+*
+0819200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+*
+1310720

tests/btrfs/group

@@ -233,3 +233,4 @@
 228 auto quick volume
 229 auto quick send clone
 230 auto quick qgroup limit
+231 auto quick clone log replay