[PATCH 1/2] generic/740: set env for mkfs.exfat

[PATCH 1/2] generic/740: set env for mkfs.exfat

[David Timber]

Foreign filesystem detection is added in exfatprogs version 1.4.1. To
maintain backward compatibility, mkfs.exfat refuses to format the device
only when it's run from terminal with a tty associated to it.

This is similar to how e2fsprogs work around the issue. However,
with exfatprogs, this behaviour can be overridden with the special
environment variable EXFAT_TTY_OVERRIDE to simulate shell invocation by
user.

Signed-off-by: David Timber <dxdt@dev.snart.me>
---
 tests/generic/740 | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/tests/generic/740 b/tests/generic/740
index ce55200f..4f8bf099 100755
--- a/tests/generic/740
+++ b/tests/generic/740
@@ -28,6 +28,18 @@ _require_block_device "${SCRATCH_DEV}"
 # not all the FS support zoned block device
 _require_non_zoned_device "${SCRATCH_DEV}"
 
+mkfs_preop=""
+mkfs_preargs=""
+mkfs_postargs=""
+
+case "$FSTYP" in
+exfat)
+	# For backward compatibility, mkfs.exfat refuses to format only when run
+	# from a tty. This env var should override the behaviour if supported.
+	mkfs_preop="EXFAT_TTY_OVERRIDE=1"
+	;;
+esac
+
 echo "Silence is golden."
 for fs in `echo ${MKFS_PROG}.* | sed -e "s:${MKFS_PROG}.::g"`
 do
@@ -83,7 +95,8 @@ do
 		# next, ensure we don't overwrite it
 
 		echo "=== Attempting $FSTYP overwrite of $fs..." >>$seqres.full
-		${MKFS_PROG} -t $FSTYP $SCRATCH_DEV >>$seqres.full 2>&1
+		eval $mkfs_preop ${MKFS_PROG} -t $FSTYP $mkfs_preargs $SCRATCH_DEV $mkfs_postargs \
+			>>$seqres.full 2>&1
 
 		[ $? -eq 0 ] && echo "Failed - overwrote fs type ${fs}!"
 	else
-- 
2.54.0

[PATCH 2/2] generic/740: add --force option to mkfs.ntfs

[David Timber]

mkntfs refuses to format the target if it's backed by a "real" device
but not a partition to maintain compatibility with Windows. When
formatting the scratch device in NTFS for testing, this behaviour has
to be overridden so that any type of blockdev can be used as a scratch
device.

Signed-off-by: David Timber <dxdt@dev.snart.me>
---
 tests/generic/740 | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tests/generic/740 b/tests/generic/740
index 4f8bf099..718d983d 100755
--- a/tests/generic/740
+++ b/tests/generic/740
@@ -72,8 +72,10 @@ do
 		postargs=2000
 		;;
 	ntfs)
-		# "quick" format that doesn't zero the entire device
-		postargs="--quick"
+		# "quick" format that doesn't zero the entire device. Use -F so
+		# that NTFS-3G mkfs formats the volume even if the scratch
+		# blockdev is not a partition.
+		postargs="--quick --force"
 		;;
 	reiser4)
 		preop="echo y |"
-- 
2.54.0

Re: [PATCH 2/2] generic/740: add --force option to mkfs.ntfs

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH 2/2] generic/740: add --force option to mkfs.ntfs

[Darrick J. Wong]

On Fri, Jun 19, 2026 at 04:22:36AM +0900, David Timber wrote:
> mkntfs refuses to format the target if it's backed by a "real" device
> but not a partition to maintain compatibility with Windows. When
> formatting the scratch device in NTFS for testing, this behaviour has
> to be overridden so that any type of blockdev can be used as a scratch
> device.
> 
> Signed-off-by: David Timber <dxdt@dev.snart.me>
> ---
>  tests/generic/740 | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/generic/740 b/tests/generic/740
> index 4f8bf099..718d983d 100755
> --- a/tests/generic/740
> +++ b/tests/generic/740
> @@ -72,8 +72,10 @@ do
>  		postargs=2000
>  		;;
>  	ntfs)
> -		# "quick" format that doesn't zero the entire device
> -		postargs="--quick"
> +		# "quick" format that doesn't zero the entire device. Use -F so

"Use --force..." ?

--D

> +		# that NTFS-3G mkfs formats the volume even if the scratch
> +		# blockdev is not a partition.
> +		postargs="--quick --force"
>  		;;
>  	reiser4)
>  		preop="echo y |"
> -- 
> 2.54.0
> 
> 

Re: [PATCH 1/2] generic/740: set env for mkfs.exfat

[Christoph Hellwig]

On Fri, Jun 19, 2026 at 04:22:35AM +0900, David Timber wrote:
> Foreign filesystem detection is added in exfatprogs version 1.4.1. To
> maintain backward compatibility, mkfs.exfat refuses to format the device
> only when it's run from terminal with a tty associated to it.
> 
> This is similar to how e2fsprogs work around the issue. However,
> with exfatprogs, this behaviour can be overridden with the special
> environment variable EXFAT_TTY_OVERRIDE to simulate shell invocation by
> user.
> 
> Signed-off-by: David Timber <dxdt@dev.snart.me>
> ---
>  tests/generic/740 | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/tests/generic/740 b/tests/generic/740
> index ce55200f..4f8bf099 100755
> --- a/tests/generic/740
> +++ b/tests/generic/740
> @@ -28,6 +28,18 @@ _require_block_device "${SCRATCH_DEV}"
>  # not all the FS support zoned block device
>  _require_non_zoned_device "${SCRATCH_DEV}"
>  
> +mkfs_preop=""
> +mkfs_preargs=""
> +mkfs_postargs=""
> +
> +case "$FSTYP" in
> +exfat)
> +	# For backward compatibility, mkfs.exfat refuses to format only when run
> +	# from a tty. This env var should override the behaviour if supported.
> +	mkfs_preop="EXFAT_TTY_OVERRIDE=1"
> +	;;
> +esac
> +
>  echo "Silence is golden."
>  for fs in `echo ${MKFS_PROG}.* | sed -e "s:${MKFS_PROG}.::g"`
>  do
> @@ -83,7 +95,8 @@ do
>  		# next, ensure we don't overwrite it
>  
>  		echo "=== Attempting $FSTYP overwrite of $fs..." >>$seqres.full
> -		${MKFS_PROG} -t $FSTYP $SCRATCH_DEV >>$seqres.full 2>&1
> +		eval $mkfs_preop ${MKFS_PROG} -t $FSTYP $mkfs_preargs $SCRATCH_DEV $mkfs_postargs \

breaking up the long line still would be nice here, i.e. keep at 80
characters.  Else looks good.

Re: [PATCH 1/2] generic/740: set env for mkfs.exfat

[Darrick J. Wong]

On Fri, Jun 19, 2026 at 06:53:06AM +0200, Christoph Hellwig wrote:
> On Fri, Jun 19, 2026 at 04:22:35AM +0900, David Timber wrote:
> > Foreign filesystem detection is added in exfatprogs version 1.4.1. To
> > maintain backward compatibility, mkfs.exfat refuses to format the device
> > only when it's run from terminal with a tty associated to it.
> > 
> > This is similar to how e2fsprogs work around the issue. However,
> > with exfatprogs, this behaviour can be overridden with the special
> > environment variable EXFAT_TTY_OVERRIDE to simulate shell invocation by
> > user.
> > 
> > Signed-off-by: David Timber <dxdt@dev.snart.me>
> > ---
> >  tests/generic/740 | 15 ++++++++++++++-
> >  1 file changed, 14 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tests/generic/740 b/tests/generic/740
> > index ce55200f..4f8bf099 100755
> > --- a/tests/generic/740
> > +++ b/tests/generic/740
> > @@ -28,6 +28,18 @@ _require_block_device "${SCRATCH_DEV}"
> >  # not all the FS support zoned block device
> >  _require_non_zoned_device "${SCRATCH_DEV}"
> >  
> > +mkfs_preop=""
> > +mkfs_preargs=""
> > +mkfs_postargs=""
> > +
> > +case "$FSTYP" in
> > +exfat)
> > +	# For backward compatibility, mkfs.exfat refuses to format only when run
> > +	# from a tty. This env var should override the behaviour if supported.
> > +	mkfs_preop="EXFAT_TTY_OVERRIDE=1"
> > +	;;
> > +esac
> > +
> >  echo "Silence is golden."
> >  for fs in `echo ${MKFS_PROG}.* | sed -e "s:${MKFS_PROG}.::g"`
> >  do
> > @@ -83,7 +95,8 @@ do
> >  		# next, ensure we don't overwrite it
> >  
> >  		echo "=== Attempting $FSTYP overwrite of $fs..." >>$seqres.full
> > -		${MKFS_PROG} -t $FSTYP $SCRATCH_DEV >>$seqres.full 2>&1
> > +		eval $mkfs_preop ${MKFS_PROG} -t $FSTYP $mkfs_preargs $SCRATCH_DEV $mkfs_postargs \
> 
> breaking up the long line still would be nice here, i.e. keep at 80
> characters.  Else looks good.

I wonder why we don't just redirect stdin from /dev/null, it's not like
we want to capture user input anyway...

--D