scratch rtdev handling improvements

scratch rtdev handling improvements

[Christoph Hellwig]

Hi all,

this series improves handling of the scratch rtdev.  It is a combination
of Darrick's earlier patches for xfs/655 and xfs/656 and my earlier
patch for a common helper so that they don't conflict.

[PATCH 1/3] xfs/656: rearrange directio pread/pwrite for zoned filesystems

[Christoph Hellwig]

From: "Darrick J. Wong" <djwong@kernel.org>

On zoned filesystems, a write failure shuts down the filesystem, which
makes this test fail with:

 --- /run/fstests/bin/tests/xfs/656.out	2026-03-13 16:19:08.152939212 -0700
 +++ /run/fstests/logs/xfs/656.out.bad	2026-06-30 18:16:43.847849604 -0700
 @@ -1,10 +1,9 @@
  QA output created by 656
  Format and mount
  pwrite: Input/output error
 -pread: Input/output error
 +stat: Input/output error
  pread: Input/output error
  fsync: Input/output error
  VICTIM pos NUM len NUM: directio_write: Input/output error
 -VICTIM pos NUM len NUM: directio_read: Input/output error
  VICTIM pos NUM len NUM: buffered_read: Input/output error
  VICTIM pos NUM len NUM: buffered_write: Input/output error

Reorder the directio pread and pwrite to avoid this unnecessary failure.
Note that we cycle the mount between the direct and buffered io tests,
which is why we only need to fix the directio test.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 tests/xfs/656     | 2 +-
 tests/xfs/656.out | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/xfs/656 b/tests/xfs/656
index 3830d7193fcb..c01276eb384b 100755
--- a/tests/xfs/656
+++ b/tests/xfs/656
@@ -66,8 +66,8 @@ $XFS_IO_PROG -c 'healthmon -c -v' $SCRATCH_MNT >> $tmp.healthmon &
 healer_pid=$!
 sleep 1	# wait for program to start up
 _dmerror_load_error_table
-$XFS_IO_PROG -d -c 'pwrite -b 256k 12k 16k' $testfile >> $seqres.full
 $XFS_IO_PROG -d -c 'pread -b 256k 10g 16k' $testfile >> $seqres.full
+$XFS_IO_PROG -d -c 'pwrite -b 256k 12k 16k' $testfile >> $seqres.full
 _dmerror_load_working_table
 
 _dmerror_unmount
diff --git a/tests/xfs/656.out b/tests/xfs/656.out
index 83b2f5948a77..4d6633060acd 100644
--- a/tests/xfs/656.out
+++ b/tests/xfs/656.out
@@ -1,10 +1,10 @@
 QA output created by 656
 Format and mount
-pwrite: Input/output error
 pread: Input/output error
+pwrite: Input/output error
 pread: Input/output error
 fsync: Input/output error
-VICTIM pos NUM len NUM: directio_write: Input/output error
 VICTIM pos NUM len NUM: directio_read: Input/output error
+VICTIM pos NUM len NUM: directio_write: Input/output error
 VICTIM pos NUM len NUM: buffered_read: Input/output error
 VICTIM pos NUM len NUM: buffered_write: Input/output error
-- 
2.53.0

[PATCH 2/3] xfs/65[56]: don't unset SCRATCH_RTDEV here

[Christoph Hellwig]

From: "Darrick J. Wong" <djwong@kernel.org>

Both of these tests claim that they have to unset SCRATCH_RTDEV to avoid
formatting failures due to the rt bitmap consuming all the space in the
"small" data device.  However, the format doesn't constrain the size of
the data device, so the justification doesn't apply.  Remove the whole
thing.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 tests/xfs/655 | 4 ----
 tests/xfs/656 | 4 ----
 2 files changed, 8 deletions(-)

diff --git a/tests/xfs/655 b/tests/xfs/655
index a4162d70b321..9d09cc000531 100755
--- a/tests/xfs/655
+++ b/tests/xfs/655
@@ -24,10 +24,6 @@ _require_scratch_nocheck
 _require_scratch_xfs_crc # can't detect minor corruption w/o crc
 _require_xfs_io_command healthmon
 
-# Disable the scratch rt device to avoid test failures relating to the rt
-# bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
-
 echo "Format and mount"
 _scratch_mkfs -d agcount=1 | _filter_mkfs 2> $tmp.mkfs >> $seqres.full
 . $tmp.mkfs
diff --git a/tests/xfs/656 b/tests/xfs/656
index c01276eb384b..5114a6c24003 100755
--- a/tests/xfs/656
+++ b/tests/xfs/656
@@ -40,10 +40,6 @@ filter_healer_errors() {
 		uniq
 }
 
-# Disable the scratch rt device to avoid test failures relating to the rt
-# bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
-
 echo "Format and mount"
 _scratch_mkfs > $seqres.full 2>&1
 _dmerror_init no_log
-- 
2.53.0

[PATCH 3/3] formalize and fix disabling the RT subvolume

[Christoph Hellwig]

Various test unset SCRATCH_RTDEV to avoid dealing with metadata
allocations for the RT subvolume in the main device or differences
in RT subvolume behavior.  Besides being rather ad-hoc, this unset
also fails to disable the internal RT zoned subvolume.

Add a _disable_scratch_realtime helper that not only unsets
SCRATCH_RTDEV, but also disables the zoned allocator and with
that the internal RT subvolume.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 common/filestreams | 2 +-
 common/rc          | 9 +++++++++
 tests/generic/250  | 2 +-
 tests/generic/252  | 2 +-
 tests/generic/441  | 2 +-
 tests/generic/484  | 2 +-
 tests/generic/487  | 2 +-
 tests/xfs/076      | 2 +-
 tests/xfs/189      | 2 +-
 tests/xfs/205      | 2 +-
 tests/xfs/306      | 2 +-
 tests/xfs/444      | 2 +-
 tests/xfs/445      | 2 +-
 13 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/common/filestreams b/common/filestreams
index 2d83a3661b01..c5421ef3ff2b 100644
--- a/common/filestreams
+++ b/common/filestreams
@@ -84,7 +84,7 @@ _test_streams() {
 	# Disable the scratch rt device to avoid test failures relating to the
 	# rt bitmap consuming free space in our small data device and throwing
 	# off the filestreams allocator.
-	unset SCRATCH_RTDEV
+	_disable_scratch_realtime
 
 	# Skip these tests on zoned file systems as filestreams don't work
 	# with the zoned allocator, and the operation below would force it into
diff --git a/common/rc b/common/rc
index 4947255479ca..d8d4d5292f8c 100644
--- a/common/rc
+++ b/common/rc
@@ -2435,6 +2435,15 @@ _require_no_realtime()
 		_notrun "Test not compatible with realtime subvolumes, skipped this test"
 }
 
+# Disable usage of internal or external scratch devices
+_disable_scratch_realtime()
+{
+	unset SCRATCH_RTDEV
+	if [ "$FSTYP" = "xfs" ]; then
+		MKFS_OPTIONS="${MKFS_OPTIONS//-r zoned=1}"
+	fi
+}
+
 # this test requires that a specified command (executable) exists
 # $1 - command, $2 - name for error message
 #
diff --git a/tests/generic/250 b/tests/generic/250
index 605d7c8ade3d..32326114798c 100755
--- a/tests/generic/250
+++ b/tests/generic/250
@@ -29,7 +29,7 @@ _require_odirect
 
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 fssize=$((196 * 1048576))
 echo "Format and mount"
diff --git a/tests/generic/252 b/tests/generic/252
index 2ad0524c2037..2e462b61fce4 100755
--- a/tests/generic/252
+++ b/tests/generic/252
@@ -30,7 +30,7 @@ AIO_TEST="$here/src/aio-dio-regress/aiocp"
 
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 fssize=$((196 * 1048576))
 echo "Format and mount"
diff --git a/tests/generic/441 b/tests/generic/441
index cc370bea5052..c3a096926eaf 100755
--- a/tests/generic/441
+++ b/tests/generic/441
@@ -47,7 +47,7 @@ _require_test_program dmerror
 
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 echo "Format and mount"
 _scratch_mkfs > $seqres.full 2>&1
diff --git a/tests/generic/484 b/tests/generic/484
index 0455efcb6000..e2fea8c6b18d 100755
--- a/tests/generic/484
+++ b/tests/generic/484
@@ -35,7 +35,7 @@ _require_xfs_io_command "syncfs"
 
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 echo "Format and mount"
 _scratch_mkfs > $seqres.full 2>&1
diff --git a/tests/generic/487 b/tests/generic/487
index 364f7eb4c032..cc6c8f0e63d9 100755
--- a/tests/generic/487
+++ b/tests/generic/487
@@ -40,7 +40,7 @@ _require_dm_target error
 
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 echo "Format and mount"
 _scratch_mkfs > $seqres.full 2>&1
diff --git a/tests/xfs/076 b/tests/xfs/076
index 2ea6459b0dbe..103ad7509e0f 100755
--- a/tests/xfs/076
+++ b/tests/xfs/076
@@ -66,7 +66,7 @@ _require_xfs_sparse_inodes
 
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 _scratch_mkfs "-d size=96m -m crc=1 -i sparse" | tee -a $seqres.full | \
 	_filter_mkfs > /dev/null 2> $tmp.mkfs
diff --git a/tests/xfs/189 b/tests/xfs/189
index 1770023760fd..aa9712afac35 100755
--- a/tests/xfs/189
+++ b/tests/xfs/189
@@ -250,7 +250,7 @@ _require_no_realtime
 _require_scratch
 _require_noattr2
 
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 unset SCRATCH_LOGDEV
 
 _scratch_mkfs_xfs | _filter_mkfs 2>/dev/null
diff --git a/tests/xfs/205 b/tests/xfs/205
index 73d51d8d602f..7d8c0e5e33dc 100755
--- a/tests/xfs/205
+++ b/tests/xfs/205
@@ -18,7 +18,7 @@ _require_scratch_nocheck
 
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 fsblksz=1024
 _scratch_mkfs_xfs -d size=$((32768*fsblksz)) -b size=$fsblksz >> $seqres.full 2>&1
diff --git a/tests/xfs/306 b/tests/xfs/306
index d48b753632d5..60c2b486f671 100755
--- a/tests/xfs/306
+++ b/tests/xfs/306
@@ -26,7 +26,7 @@ _require_test_program "punch-alternating"
 
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming all the free space in our small data device.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 # Create a small fs with a large directory block size. We want to fill up the fs
 # quickly and then create multi-fsb dirblocks over fragmented free space.
diff --git a/tests/xfs/444 b/tests/xfs/444
index 13c9de528ec8..949c5711e2c8 100755
--- a/tests/xfs/444
+++ b/tests/xfs/444
@@ -31,7 +31,7 @@ _require_scratch_xfs_crc
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming free space in our small data device and throwing off the
 # filestreams allocator.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 mount_loop() {
 	if ! _try_scratch_mount >> $seqres.full 2>&1; then
diff --git a/tests/xfs/445 b/tests/xfs/445
index 0ea85ad018d6..2e9b6ca1be34 100755
--- a/tests/xfs/445
+++ b/tests/xfs/445
@@ -42,7 +42,7 @@ _check_filestreams_support || _notrun "filestreams not available"
 # Disable the scratch rt device to avoid test failures relating to the rt
 # bitmap consuming free space in our small data device and throwing off the
 # filestreams allocator.
-unset SCRATCH_RTDEV
+_disable_scratch_realtime
 
 # use small AGs for frequent stream switching
 _scratch_mkfs_xfs -d agsize=20m,size=2g >> $seqres.full 2>&1
-- 
2.53.0

Re: [PATCH 3/3] formalize and fix disabling the RT subvolume

[Darrick J. Wong]

On Fri, Jul 10, 2026 at 07:27:35AM +0200, Christoph Hellwig wrote:
> Various test unset SCRATCH_RTDEV to avoid dealing with metadata
> allocations for the RT subvolume in the main device or differences
> in RT subvolume behavior.  Besides being rather ad-hoc, this unset
> also fails to disable the internal RT zoned subvolume.
> 
> Add a _disable_scratch_realtime helper that not only unsets
> SCRATCH_RTDEV, but also disables the zoned allocator and with
> that the internal RT subvolume.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good to me now! :)

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  common/filestreams | 2 +-
>  common/rc          | 9 +++++++++
>  tests/generic/250  | 2 +-
>  tests/generic/252  | 2 +-
>  tests/generic/441  | 2 +-
>  tests/generic/484  | 2 +-
>  tests/generic/487  | 2 +-
>  tests/xfs/076      | 2 +-
>  tests/xfs/189      | 2 +-
>  tests/xfs/205      | 2 +-
>  tests/xfs/306      | 2 +-
>  tests/xfs/444      | 2 +-
>  tests/xfs/445      | 2 +-
>  13 files changed, 21 insertions(+), 12 deletions(-)
> 
> diff --git a/common/filestreams b/common/filestreams
> index 2d83a3661b01..c5421ef3ff2b 100644
> --- a/common/filestreams
> +++ b/common/filestreams
> @@ -84,7 +84,7 @@ _test_streams() {
>  	# Disable the scratch rt device to avoid test failures relating to the
>  	# rt bitmap consuming free space in our small data device and throwing
>  	# off the filestreams allocator.
> -	unset SCRATCH_RTDEV
> +	_disable_scratch_realtime
>  
>  	# Skip these tests on zoned file systems as filestreams don't work
>  	# with the zoned allocator, and the operation below would force it into
> diff --git a/common/rc b/common/rc
> index 4947255479ca..d8d4d5292f8c 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -2435,6 +2435,15 @@ _require_no_realtime()
>  		_notrun "Test not compatible with realtime subvolumes, skipped this test"
>  }
>  
> +# Disable usage of internal or external scratch devices
> +_disable_scratch_realtime()
> +{
> +	unset SCRATCH_RTDEV
> +	if [ "$FSTYP" = "xfs" ]; then
> +		MKFS_OPTIONS="${MKFS_OPTIONS//-r zoned=1}"
> +	fi
> +}
> +
>  # this test requires that a specified command (executable) exists
>  # $1 - command, $2 - name for error message
>  #
> diff --git a/tests/generic/250 b/tests/generic/250
> index 605d7c8ade3d..32326114798c 100755
> --- a/tests/generic/250
> +++ b/tests/generic/250
> @@ -29,7 +29,7 @@ _require_odirect
>  
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming all the free space in our small data device.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  fssize=$((196 * 1048576))
>  echo "Format and mount"
> diff --git a/tests/generic/252 b/tests/generic/252
> index 2ad0524c2037..2e462b61fce4 100755
> --- a/tests/generic/252
> +++ b/tests/generic/252
> @@ -30,7 +30,7 @@ AIO_TEST="$here/src/aio-dio-regress/aiocp"
>  
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming all the free space in our small data device.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  fssize=$((196 * 1048576))
>  echo "Format and mount"
> diff --git a/tests/generic/441 b/tests/generic/441
> index cc370bea5052..c3a096926eaf 100755
> --- a/tests/generic/441
> +++ b/tests/generic/441
> @@ -47,7 +47,7 @@ _require_test_program dmerror
>  
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming all the free space in our small data device.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  echo "Format and mount"
>  _scratch_mkfs > $seqres.full 2>&1
> diff --git a/tests/generic/484 b/tests/generic/484
> index 0455efcb6000..e2fea8c6b18d 100755
> --- a/tests/generic/484
> +++ b/tests/generic/484
> @@ -35,7 +35,7 @@ _require_xfs_io_command "syncfs"
>  
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming all the free space in our small data device.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  echo "Format and mount"
>  _scratch_mkfs > $seqres.full 2>&1
> diff --git a/tests/generic/487 b/tests/generic/487
> index 364f7eb4c032..cc6c8f0e63d9 100755
> --- a/tests/generic/487
> +++ b/tests/generic/487
> @@ -40,7 +40,7 @@ _require_dm_target error
>  
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming all the free space in our small data device.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  echo "Format and mount"
>  _scratch_mkfs > $seqres.full 2>&1
> diff --git a/tests/xfs/076 b/tests/xfs/076
> index 2ea6459b0dbe..103ad7509e0f 100755
> --- a/tests/xfs/076
> +++ b/tests/xfs/076
> @@ -66,7 +66,7 @@ _require_xfs_sparse_inodes
>  
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming all the free space in our small data device.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  _scratch_mkfs "-d size=96m -m crc=1 -i sparse" | tee -a $seqres.full | \
>  	_filter_mkfs > /dev/null 2> $tmp.mkfs
> diff --git a/tests/xfs/189 b/tests/xfs/189
> index 1770023760fd..aa9712afac35 100755
> --- a/tests/xfs/189
> +++ b/tests/xfs/189
> @@ -250,7 +250,7 @@ _require_no_realtime
>  _require_scratch
>  _require_noattr2
>  
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  unset SCRATCH_LOGDEV
>  
>  _scratch_mkfs_xfs | _filter_mkfs 2>/dev/null
> diff --git a/tests/xfs/205 b/tests/xfs/205
> index 73d51d8d602f..7d8c0e5e33dc 100755
> --- a/tests/xfs/205
> +++ b/tests/xfs/205
> @@ -18,7 +18,7 @@ _require_scratch_nocheck
>  
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming all the free space in our small data device.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  fsblksz=1024
>  _scratch_mkfs_xfs -d size=$((32768*fsblksz)) -b size=$fsblksz >> $seqres.full 2>&1
> diff --git a/tests/xfs/306 b/tests/xfs/306
> index d48b753632d5..60c2b486f671 100755
> --- a/tests/xfs/306
> +++ b/tests/xfs/306
> @@ -26,7 +26,7 @@ _require_test_program "punch-alternating"
>  
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming all the free space in our small data device.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  # Create a small fs with a large directory block size. We want to fill up the fs
>  # quickly and then create multi-fsb dirblocks over fragmented free space.
> diff --git a/tests/xfs/444 b/tests/xfs/444
> index 13c9de528ec8..949c5711e2c8 100755
> --- a/tests/xfs/444
> +++ b/tests/xfs/444
> @@ -31,7 +31,7 @@ _require_scratch_xfs_crc
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming free space in our small data device and throwing off the
>  # filestreams allocator.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  mount_loop() {
>  	if ! _try_scratch_mount >> $seqres.full 2>&1; then
> diff --git a/tests/xfs/445 b/tests/xfs/445
> index 0ea85ad018d6..2e9b6ca1be34 100755
> --- a/tests/xfs/445
> +++ b/tests/xfs/445
> @@ -42,7 +42,7 @@ _check_filestreams_support || _notrun "filestreams not available"
>  # Disable the scratch rt device to avoid test failures relating to the rt
>  # bitmap consuming free space in our small data device and throwing off the
>  # filestreams allocator.
> -unset SCRATCH_RTDEV
> +_disable_scratch_realtime
>  
>  # use small AGs for frequent stream switching
>  _scratch_mkfs_xfs -d agsize=20m,size=2g >> $seqres.full 2>&1
> -- 
> 2.53.0
> 
>