[PATCH] Revert "generic/470: use thin volume for dmlogwrites target device"

["yangx.jy@xxxxxxxxxxx" <yangx.jy@xxxxxxxxxxx>]

This reverts commit fc5870da485aec0f9196a0f2bed32f73f6b2c664

generic/470 was original designed to verify mmap(MAP_SYNC) on the
log-writes device enabling DAX. As a result, we need to ensure that
all underlying devices under the log-writes device support DAX.
However the thin-volume device never supports DAX so generic/470
with the dm-thin device always gets "[not run] Cannot use thin-pool
devices on DAX capable block devices".

Besides, mmap(MAP_SYNC) will throw "mmap: Operation not supported"
even if we make generic/470 continue unconditionally.

Please see the difference between old and new logic:

          old logic                       new logic
------------------------------------------------------------
 log-writes device(DAX)              log-writes device(DAX)
           |                                   |
PMEM0(DAX) + PMEM1(DAX)   thin-volume(non-DAX) + PMEM1(DAX)
                                  |
                                PMEM0(DAX)
------------------------------------------------------------

I think it is wrong for generic/470 to use thin volume.

Signed-off-by: Xiao Yang <yangx.jy@xxxxxxxxxxx>
---
 tests/generic/470 | 23 ++++++-----------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/tests/generic/470 b/tests/generic/470
index f3407511..93a6e3f4 100755
--- a/tests/generic/470
+++ b/tests/generic/470
@@ -15,33 +15,22 @@ _cleanup()
 {
 	cd /
 	_log_writes_cleanup
-	_dmthin_cleanup
 	rm -f $tmp.*
 }
 
 # Import common functions.
 . ./common/filter
-. ./common/dmthin
 . ./common/dmlogwrites
 
 # real QA test starts here
 _supported_fs generic
-_require_scratch_nocheck
+_require_scratch
 _require_no_logdev
 _require_log_writes_dax_mountopt "dax"
-_require_dm_target thin-pool
 _require_xfs_io_command "mmap" "-S"
 _require_xfs_io_command "log_writes"
 
-devsize=$((1024*1024*200 / 512))        # 200m phys/virt size
-csize=$((1024*64 / 512))                # 64k cluster size
-lowspace=$((1024*1024 / 512))           # 1m low space threshold
-
-# Use a thin device to provide deterministic discard behavior. Discards are used
-# by the log replay tool for fast zeroing to prevent out-of-order replay issues.
-_dmthin_init $devsize $devsize $csize $lowspace
-
-_log_writes_init $DMTHIN_VOL_DEV
+_log_writes_init $SCRATCH_DEV
 _log_writes_mkfs >> $seqres.full 2>&1
 _log_writes_mount -o dax
 
@@ -54,14 +43,14 @@ $XFS_IO_PROG -t -c "truncate $LEN" -c "mmap -S 0 $LEN" -c "mwrite 0 $LEN" \
 # Unmount the scratch dir and tear down the log writes target
 _log_writes_unmount
 _log_writes_remove
-_dmthin_check_fs
+_check_scratch_fs
 
 # destroy previous filesystem so we can be sure our rebuild works
-_mkfs_dev $DMTHIN_VOL_DEV >> $seqres.full 2>&1
+_scratch_mkfs >> $seqres.full 2>&1
 
 # check pre-unmap state
-_log_writes_replay_log preunmap $DMTHIN_VOL_DEV
-_dmthin_mount
+_log_writes_replay_log preunmap $SCRATCH_DEV
+_scratch_mount
 
 # We should see $SCRATCH_MNT/test as having 1 MiB in block allocations
 du -sh $SCRATCH_MNT/test | _filter_scratch | _filter_spaces
-- 
2.34.1