[PATCH v2 1/4] common/config: remove redundant export variables

[PATCH v2 1/4] common/config: remove redundant export variables

[Chao Yu]

F2FS_IO_PROG and TIMEOUT_PROG are exported twice, remove the redundant
one.

Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: David Disseldorp <ddiss@suse.de>
---
v2:
- remove another redundant export variable
 common/config | 2 --
 1 file changed, 2 deletions(-)

diff --git a/common/config b/common/config
index 2afbda14..aa525825 100644
--- a/common/config
+++ b/common/config
@@ -191,7 +191,6 @@ export XFS_COPY_PROG="$(type -P xfs_copy)"
 export FSTRIM_PROG="$(type -P fstrim)"
 export DUMPE2FS_PROG="$(type -P dumpe2fs)"
 export RESIZE2FS_PROG="$(type -P resize2fs)"
-export F2FS_IO_PROG="$(type -P f2fs_io)"
 export FIO_PROG="$(type -P fio)"
 export FILEFRAG_PROG="$(type -P filefrag)"
 export E4DEFRAG_PROG="$(type -P e4defrag)"
@@ -220,7 +219,6 @@ export UBIUPDATEVOL_PROG="$(type -P ubiupdatevol)"
 export THIN_CHECK_PROG="$(type -P thin_check)"
 export PYTHON3_PROG="$(type -P python3)"
 export SQLITE3_PROG="$(type -P sqlite3)"
-export TIMEOUT_PROG="$(type -P timeout)"
 export SETCAP_PROG="$(type -P setcap)"
 export GETCAP_PROG="$(type -P getcap)"
 export CAPSH_PROG="$(type -P capsh)"
-- 
2.48.1

[PATCH v2 2/4] common/config: export F2FS_INJECT_PROG

[Chao Yu]

export F2FS_INJECT_PROG w/ inject.f2fs, it can be used for fault injection.

Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: David Disseldorp <ddiss@suse.de>
---
v2:
- no changes
 common/config | 1 +
 1 file changed, 1 insertion(+)

diff --git a/common/config b/common/config
index aa525825..7d017a05 100644
--- a/common/config
+++ b/common/config
@@ -316,6 +316,7 @@ export MKFS_BTRFS_PROG=$(set_mkfs_prog_path_with_opts btrfs)
 export MKFS_F2FS_PROG=$(set_mkfs_prog_path_with_opts f2fs)
 export DUMP_F2FS_PROG=$(type -P dump.f2fs)
 export F2FS_IO_PROG=$(type -P f2fs_io)
+export F2FS_INJECT_PROG=$(type -P inject.f2fs)
 export BTRFS_UTIL_PROG=$(type -P btrfs)
 export BTRFS_SHOW_SUPER_PROG=$(type -P btrfs-show-super)
 export BTRFS_CONVERT_PROG=$(type -P btrfs-convert)
-- 
2.48.1

[PATCH v2 3/4] common/rc: support f2fs in _repair_scratch_fs

[Chao Yu]

Support f2fs in _repair_scratch_fs(), and use -f to repair the image
forcely.

Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: David Disseldorp <ddiss@suse.de>
---
v2:
- no changes
 common/rc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/common/rc b/common/rc
index ca755055..bf24da4e 100644
--- a/common/rc
+++ b/common/rc
@@ -1500,6 +1500,9 @@ _repair_scratch_fs()
 	# want the test to fail:
 	_check_scratch_fs
 	;;
+    f2fs)
+	fsck -t $FSTYP -f $SCRATCH_DEV
+	;;
     *)
 	local dev=$SCRATCH_DEV
 	local fstyp=$FSTYP
-- 
2.48.1

[PATCH v2 4/4] f2fs/009: detect and repair nlink corruption

[Chao Yu]

This is a regression test to check whether fsck can handle corrupted
nlinks correctly, it uses inject.f2fs to inject nlinks w/ wrong value,
and expects fsck.f2fs can detect such corruption and do the repair.

Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Chao Yu <chao@kernel.org>
---
v2:
- make _scratch_mkfs() to format f2fs image forcely
- adjust _check_scratch_fs() to allow specified parameter of f2fs
- add _fixed_by_git_commit
- add _require_command inject.f2fs
- simply return value handling
 common/rc          |   9 ++-
 tests/f2fs/009     | 133 +++++++++++++++++++++++++++++++++++++++++++++
 tests/f2fs/009.out |   2 +
 3 files changed, 143 insertions(+), 1 deletion(-)
 create mode 100755 tests/f2fs/009
 create mode 100644 tests/f2fs/009.out

diff --git a/common/rc b/common/rc
index bf24da4e..e156f3af 100644
--- a/common/rc
+++ b/common/rc
@@ -993,7 +993,7 @@ _scratch_mkfs()
 		mkfs_filter="grep -v -e ^Warning: -e \"^mke2fs \""
 		;;
 	f2fs)
-		mkfs_cmd="$MKFS_F2FS_PROG"
+		mkfs_cmd="$MKFS_F2FS_PROG -f"
 		mkfs_filter="cat"
 		;;
 	ocfs2)
@@ -3682,6 +3682,13 @@ _check_scratch_fs()
     ubifs)
 	# there is no fsck program for ubifs yet
 	;;
+    f2fs)
+        if [ "$FSCK_OPTIONS" == "--dry-run" ]; then
+            fsck -t $FSTYP $device -- $FSCK_OPTIONS >> $seqres.full 2>&1
+        else
+            _check_generic_filesystem $device
+        fi
+        ;;
     *)
 	_check_generic_filesystem $device
 	;;
diff --git a/tests/f2fs/009 b/tests/f2fs/009
new file mode 100755
index 00000000..d14df968
--- /dev/null
+++ b/tests/f2fs/009
@@ -0,0 +1,133 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2025 Chao Yu.  All Rights Reserved.
+#
+# FS QA Test No. f2fs/009
+#
+# This is a regression test to check whether fsck can handle corrupted
+# nlinks correctly, it uses inject.f2fs to inject nlinks w/ wrong value,
+# and expects fsck.f2fs can detect such corruption and do the repair.
+#
+. ./common/preamble
+_begin_fstest auto quick
+
+_require_scratch
+_require_command "$F2FS_INJECT_PROG" inject.f2fs
+
+_fixed_by_git_commit f2fs-tools 958cd6e
+
+filename=$SCRATCH_MNT/foo
+hardlink=$SCRATCH_MNT/bar
+
+for ((i=0;i<14;i++)) do
+	echo "round: " $i >> $seqres.full
+
+	_scratch_mkfs "-f" >> $seqres.full
+	_scratch_mount >> $seqres.full
+
+	if [ $i == 0 ]; then
+		touch $filename
+		ino=`stat -c '%i' $filename`
+		nlink=0
+	elif [ $i == 1 ]; then
+		mkdir $filename
+		ino=`stat -c '%i' $filename`
+		nlink=1
+	elif [ $i == 2 ]; then
+		mknod $filename c 9 0
+		ino=`stat -c '%i' $filename`
+		nlink=0
+	elif [ $i == 3 ]; then
+		mknod $filename b 8 0
+		ino=`stat -c '%i' $filename`
+		nlink=0
+	elif [ $i == 4 ]; then
+		mkfifo $filename
+		ino=`stat -c '%i' $filename`
+		nlink=0
+	elif [ $i == 5 ]; then
+		socket -s $filename >> $seqres.full 2>&1 &
+		pid=$!
+		sleep 2
+		ino=`stat -c '%i' $filename`
+		kill $pid >> $seqres.full 2>&1
+		nlink=0
+	elif [ $i == 6 ]; then
+		ln -s $SCRATCH_MNT/empty $filename
+		ino=`stat -c '%i' $filename`
+		nlink=0
+	elif [ $i == 7 ]; then
+		# orphan inode
+		touch $filename
+		ino=`stat -c '%i' $filename`
+		$F2FS_IO_PROG write 1 0 1 zero atomic_commit $filename 5000 >> $seqres.full 2>&1 &
+		stat $filename >> $seqres.full
+		rm $filename
+		$F2FS_IO_PROG shutdown 1 $SCRATCH_MNT/ >> $seqres.full
+		sleep 6
+		nlink=1
+	elif [ $i == 8 ]; then
+		# hardlink on file
+		touch $filename
+		ino=`stat -c '%i' $filename`
+		ln $filename $hardlink
+		nlink=0
+	elif [ $i == 9 ]; then
+		# hardlink on charactor
+		mknod $filename c 9 0
+		ino=`stat -c '%i' $filename`
+		ln $filename $hardlink
+		nlink=0
+	elif [ $i == 10 ]; then
+		# hardlink on blockdev
+		mknod $filename b 8 0
+		ino=`stat -c '%i' $filename`
+		ln $filename $hardlink
+		nlink=0
+	elif [ $i == 11 ]; then
+		# hardlink on pipe
+		mkfifo $filename
+		ino=`stat -c '%i' $filename`
+		ln $filename $hardlink
+		nlink=0
+	elif [ $i == 12 ]; then
+		# hardlink on socket
+		socket -s $filename >> $seqres.full 2>&1 &
+		pid=$!
+		sleep 2
+		ino=`stat -c '%i' $filename`
+		kill $pid >> $seqres.full 2>&1
+		ln $filename $hardlink
+		nlink=0
+	elif [ $i == 13 ]; then
+		# hardlink on symlink
+		ln -s $SCRATCH_MNT/empty $filename
+		ino=`stat -c '%i' $filename`
+		ln $filename $hardlink
+		nlink=0
+	fi
+
+	if [ $i != 7 ]; then
+		stat $SCRATCH_MNT/* >> $seqres.full
+	fi
+	echo "ino:"$ino >> $seqres.full
+	echo "nlink:"$nlink >> $seqres.full
+
+	_scratch_unmount
+
+	$F2FS_INJECT_PROG --node --mb i_links --nid $ino --val $nlink $SCRATCH_DEV \
+		>> $seqres.full || _fail "fail to inject"
+
+	export FSCK_OPTIONS="--dry-run"
+	_check_scratch_fs >>$seqres.full 2>&1 && _fail "can't find corruption"
+	_repair_scratch_fs >> $seqres.full
+	_check_scratch_fs
+
+	_scratch_mount
+	_scratch_unmount
+done
+
+echo "Silence is golden"
+
+status=0
+exit
diff --git a/tests/f2fs/009.out b/tests/f2fs/009.out
new file mode 100644
index 00000000..7e977155
--- /dev/null
+++ b/tests/f2fs/009.out
@@ -0,0 +1,2 @@
+QA output created by 009
+Silence is golden
-- 
2.48.1

Re: [PATCH v2 4/4] f2fs/009: detect and repair nlink corruption

[Zorro Lang]

On Mon, Mar 10, 2025 at 07:56:21PM +0800, Chao Yu wrote:
> This is a regression test to check whether fsck can handle corrupted
> nlinks correctly, it uses inject.f2fs to inject nlinks w/ wrong value,
> and expects fsck.f2fs can detect such corruption and do the repair.
> 
> Cc: Jaegeuk Kim <jaegeuk@kernel.org>
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
> v2:
> - make _scratch_mkfs() to format f2fs image forcely
> - adjust _check_scratch_fs() to allow specified parameter of f2fs
> - add _fixed_by_git_commit
> - add _require_command inject.f2fs
> - simply return value handling
>  common/rc          |   9 ++-
>  tests/f2fs/009     | 133 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/f2fs/009.out |   2 +
>  3 files changed, 143 insertions(+), 1 deletion(-)
>  create mode 100755 tests/f2fs/009
>  create mode 100644 tests/f2fs/009.out
> 
> diff --git a/common/rc b/common/rc
> index bf24da4e..e156f3af 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -993,7 +993,7 @@ _scratch_mkfs()
>  		mkfs_filter="grep -v -e ^Warning: -e \"^mke2fs \""
>  		;;
>  	f2fs)
> -		mkfs_cmd="$MKFS_F2FS_PROG"
> +		mkfs_cmd="$MKFS_F2FS_PROG -f"
>  		mkfs_filter="cat"
>  		;;
>  	ocfs2)
> @@ -3682,6 +3682,13 @@ _check_scratch_fs()
>      ubifs)
>  	# there is no fsck program for ubifs yet
>  	;;
> +    f2fs)
> +        if [ "$FSCK_OPTIONS" == "--dry-run" ]; then
> +            fsck -t $FSTYP $device -- $FSCK_OPTIONS >> $seqres.full 2>&1
> +        else
> +            _check_generic_filesystem $device
> +        fi

If the "--dry-run" of fsck.f2fs is similar with "-n -y" of fsck.ext4. Then
you might need to change the fsck_opts() function in common/config.

  _fsck_opts()
  {
        case $FSTYP in
        ext2|ext3|ext4)
                export FSCK_OPTIONS="-nf"
                ;;
        reiser*)
                export FSCK_OPTIONS="--yes"
                ;;
        f2fs)
                export FSCK_OPTIONS=""
                ;;
	...
  }

The default FSCK_OPTIONS for f2fs should be "--dry-run".
        f2fs)
                export FSCK_OPTIONS="--dry-run"

Then ...

[snip]

> +	$F2FS_INJECT_PROG --node --mb i_links --nid $ino --val $nlink $SCRATCH_DEV \
> +		>> $seqres.full || _fail "fail to inject"
> +
> +	export FSCK_OPTIONS="--dry-run"

... then you can save this export FSCK_OPTIONS="--dry-run". I've explained
more in your v1 patch review, refer to:

https://lore.kernel.org/fstests/20250310194818.wki325qreuta26nc@dell-per750-06-vm-08.rhts.eng.pek2.redhat.com/T/#u

Thanks,
Zorro

> +	_check_scratch_fs >>$seqres.full 2>&1 && _fail "can't find corruption"
> +	_repair_scratch_fs >> $seqres.full
> +	_check_scratch_fs
> +
> +	_scratch_mount
> +	_scratch_unmount
> +done
> +
> +echo "Silence is golden"
> +
> +status=0
> +exit
> diff --git a/tests/f2fs/009.out b/tests/f2fs/009.out
> new file mode 100644
> index 00000000..7e977155
> --- /dev/null
> +++ b/tests/f2fs/009.out
> @@ -0,0 +1,2 @@
> +QA output created by 009
> +Silence is golden
> -- 
> 2.48.1
> 

Re: [PATCH v2 4/4] f2fs/009: detect and repair nlink corruption

[Zorro Lang]

On Mon, Mar 10, 2025 at 07:56:21PM +0800, Chao Yu wrote:
> This is a regression test to check whether fsck can handle corrupted
> nlinks correctly, it uses inject.f2fs to inject nlinks w/ wrong value,
> and expects fsck.f2fs can detect such corruption and do the repair.
> 
> Cc: Jaegeuk Kim <jaegeuk@kernel.org>
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
> v2:
> - make _scratch_mkfs() to format f2fs image forcely
> - adjust _check_scratch_fs() to allow specified parameter of f2fs
> - add _fixed_by_git_commit
> - add _require_command inject.f2fs
> - simply return value handling
>  common/rc          |   9 ++-
>  tests/f2fs/009     | 133 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/f2fs/009.out |   2 +
>  3 files changed, 143 insertions(+), 1 deletion(-)
>  create mode 100755 tests/f2fs/009
>  create mode 100644 tests/f2fs/009.out
> 
> diff --git a/common/rc b/common/rc
> index bf24da4e..e156f3af 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -993,7 +993,7 @@ _scratch_mkfs()
>  		mkfs_filter="grep -v -e ^Warning: -e \"^mke2fs \""
>  		;;
>  	f2fs)
> -		mkfs_cmd="$MKFS_F2FS_PROG"
> +		mkfs_cmd="$MKFS_F2FS_PROG -f"
>  		mkfs_filter="cat"
>  		;;
>  	ocfs2)
> @@ -3682,6 +3682,13 @@ _check_scratch_fs()
>      ubifs)
>  	# there is no fsck program for ubifs yet
>  	;;
> +    f2fs)
> +        if [ "$FSCK_OPTIONS" == "--dry-run" ]; then
> +            fsck -t $FSTYP $device -- $FSCK_OPTIONS >> $seqres.full 2>&1
> +        else
> +            _check_generic_filesystem $device
> +        fi
> +        ;;
>      *)
>  	_check_generic_filesystem $device
>  	;;
> diff --git a/tests/f2fs/009 b/tests/f2fs/009
> new file mode 100755
> index 00000000..d14df968
> --- /dev/null
> +++ b/tests/f2fs/009
> @@ -0,0 +1,133 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2025 Chao Yu.  All Rights Reserved.
> +#
> +# FS QA Test No. f2fs/009
> +#
> +# This is a regression test to check whether fsck can handle corrupted
> +# nlinks correctly, it uses inject.f2fs to inject nlinks w/ wrong value,
> +# and expects fsck.f2fs can detect such corruption and do the repair.
> +#
> +. ./common/preamble
> +_begin_fstest auto quick
> +
> +_require_scratch
> +_require_command "$F2FS_INJECT_PROG" inject.f2fs
> +
> +_fixed_by_git_commit f2fs-tools 958cd6e
                                           ^^^^^^^^
                                           commit subject?

> +
> +filename=$SCRATCH_MNT/foo
> +hardlink=$SCRATCH_MNT/bar
> +
> +for ((i=0;i<14;i++)) do
> +	echo "round: " $i >> $seqres.full
> +
> +	_scratch_mkfs "-f" >> $seqres.full

As you've add "-f" in _scratch_mkfs, so this "-f" can be removed.

> +	_scratch_mount >> $seqres.full
                          ^^^^^^
                          I think it's useless

> +
> +	if [ $i == 0 ]; then
> +		touch $filename
> +		ino=`stat -c '%i' $filename`
> +		nlink=0
> +	elif [ $i == 1 ]; then
> +		mkdir $filename
> +		ino=`stat -c '%i' $filename`
> +		nlink=1
> +	elif [ $i == 2 ]; then
> +		mknod $filename c 9 0
> +		ino=`stat -c '%i' $filename`
> +		nlink=0
> +	elif [ $i == 3 ]; then
> +		mknod $filename b 8 0
> +		ino=`stat -c '%i' $filename`
> +		nlink=0
> +	elif [ $i == 4 ]; then
> +		mkfifo $filename
> +		ino=`stat -c '%i' $filename`
> +		nlink=0
> +	elif [ $i == 5 ]; then
> +		socket -s $filename >> $seqres.full 2>&1 &
                ^^^^^^

Where's the "socket" command from? I think it's not always installed on any
Linux system. fstests never use this command in any test case. If you
need this command, you might need to check that, and _notrun if it's
not installed.

> +		pid=$!

As you have background processes in this test case, you need to make sure
these processes are killed properly in _cleanup, especially if the test
is killed suddently, refer to generic/019.

Thanks,
Zorro

> +		sleep 2
> +		ino=`stat -c '%i' $filename`
> +		kill $pid >> $seqres.full 2>&1
> +		nlink=0
> +	elif [ $i == 6 ]; then
> +		ln -s $SCRATCH_MNT/empty $filename
> +		ino=`stat -c '%i' $filename`
> +		nlink=0
> +	elif [ $i == 7 ]; then
> +		# orphan inode
> +		touch $filename
> +		ino=`stat -c '%i' $filename`
> +		$F2FS_IO_PROG write 1 0 1 zero atomic_commit $filename 5000 >> $seqres.full 2>&1 &
> +		stat $filename >> $seqres.full
> +		rm $filename
> +		$F2FS_IO_PROG shutdown 1 $SCRATCH_MNT/ >> $seqres.full
> +		sleep 6
> +		nlink=1
> +	elif [ $i == 8 ]; then
> +		# hardlink on file
> +		touch $filename
> +		ino=`stat -c '%i' $filename`
> +		ln $filename $hardlink
> +		nlink=0
> +	elif [ $i == 9 ]; then
> +		# hardlink on charactor
> +		mknod $filename c 9 0
> +		ino=`stat -c '%i' $filename`
> +		ln $filename $hardlink
> +		nlink=0
> +	elif [ $i == 10 ]; then
> +		# hardlink on blockdev
> +		mknod $filename b 8 0
> +		ino=`stat -c '%i' $filename`
> +		ln $filename $hardlink
> +		nlink=0
> +	elif [ $i == 11 ]; then
> +		# hardlink on pipe
> +		mkfifo $filename
> +		ino=`stat -c '%i' $filename`
> +		ln $filename $hardlink
> +		nlink=0
> +	elif [ $i == 12 ]; then
> +		# hardlink on socket
> +		socket -s $filename >> $seqres.full 2>&1 &
> +		pid=$!
> +		sleep 2
> +		ino=`stat -c '%i' $filename`
> +		kill $pid >> $seqres.full 2>&1
> +		ln $filename $hardlink
> +		nlink=0
> +	elif [ $i == 13 ]; then
> +		# hardlink on symlink
> +		ln -s $SCRATCH_MNT/empty $filename
> +		ino=`stat -c '%i' $filename`
> +		ln $filename $hardlink
> +		nlink=0
> +	fi
> +
> +	if [ $i != 7 ]; then
> +		stat $SCRATCH_MNT/* >> $seqres.full
> +	fi
> +	echo "ino:"$ino >> $seqres.full
> +	echo "nlink:"$nlink >> $seqres.full
> +
> +	_scratch_unmount
> +
> +	$F2FS_INJECT_PROG --node --mb i_links --nid $ino --val $nlink $SCRATCH_DEV \
> +		>> $seqres.full || _fail "fail to inject"
> +
> +	export FSCK_OPTIONS="--dry-run"
> +	_check_scratch_fs >>$seqres.full 2>&1 && _fail "can't find corruption"
> +	_repair_scratch_fs >> $seqres.full
> +	_check_scratch_fs
> +
> +	_scratch_mount
> +	_scratch_unmount
> +done
> +
> +echo "Silence is golden"
> +
> +status=0
> +exit
> diff --git a/tests/f2fs/009.out b/tests/f2fs/009.out
> new file mode 100644
> index 00000000..7e977155
> --- /dev/null
> +++ b/tests/f2fs/009.out
> @@ -0,0 +1,2 @@
> +QA output created by 009
> +Silence is golden
> -- 
> 2.48.1
> 

Re: [PATCH v2 4/4] f2fs/009: detect and repair nlink corruption

[Chao Yu]

On 3/11/25 04:25, Zorro Lang wrote:
> On Mon, Mar 10, 2025 at 07:56:21PM +0800, Chao Yu wrote:
>> This is a regression test to check whether fsck can handle corrupted
>> nlinks correctly, it uses inject.f2fs to inject nlinks w/ wrong value,
>> and expects fsck.f2fs can detect such corruption and do the repair.
>>
>> Cc: Jaegeuk Kim <jaegeuk@kernel.org>
>> Signed-off-by: Chao Yu <chao@kernel.org>
>> ---
>> v2:
>> - make _scratch_mkfs() to format f2fs image forcely
>> - adjust _check_scratch_fs() to allow specified parameter of f2fs
>> - add _fixed_by_git_commit
>> - add _require_command inject.f2fs
>> - simply return value handling
>>  common/rc          |   9 ++-
>>  tests/f2fs/009     | 133 +++++++++++++++++++++++++++++++++++++++++++++
>>  tests/f2fs/009.out |   2 +
>>  3 files changed, 143 insertions(+), 1 deletion(-)
>>  create mode 100755 tests/f2fs/009
>>  create mode 100644 tests/f2fs/009.out
>>
>> diff --git a/common/rc b/common/rc
>> index bf24da4e..e156f3af 100644
>> --- a/common/rc
>> +++ b/common/rc
>> @@ -993,7 +993,7 @@ _scratch_mkfs()
>>  		mkfs_filter="grep -v -e ^Warning: -e \"^mke2fs \""
>>  		;;
>>  	f2fs)
>> -		mkfs_cmd="$MKFS_F2FS_PROG"
>> +		mkfs_cmd="$MKFS_F2FS_PROG -f"
>>  		mkfs_filter="cat"
>>  		;;
>>  	ocfs2)
>> @@ -3682,6 +3682,13 @@ _check_scratch_fs()
>>      ubifs)
>>  	# there is no fsck program for ubifs yet
>>  	;;
>> +    f2fs)
>> +        if [ "$FSCK_OPTIONS" == "--dry-run" ]; then
>> +            fsck -t $FSTYP $device -- $FSCK_OPTIONS >> $seqres.full 2>&1
>> +        else
>> +            _check_generic_filesystem $device
>> +        fi
>> +        ;;
>>      *)
>>  	_check_generic_filesystem $device
>>  	;;
>> diff --git a/tests/f2fs/009 b/tests/f2fs/009
>> new file mode 100755
>> index 00000000..d14df968
>> --- /dev/null
>> +++ b/tests/f2fs/009
>> @@ -0,0 +1,133 @@
>> +#! /bin/bash
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Copyright (c) 2025 Chao Yu.  All Rights Reserved.
>> +#
>> +# FS QA Test No. f2fs/009
>> +#
>> +# This is a regression test to check whether fsck can handle corrupted
>> +# nlinks correctly, it uses inject.f2fs to inject nlinks w/ wrong value,
>> +# and expects fsck.f2fs can detect such corruption and do the repair.
>> +#
>> +. ./common/preamble
>> +_begin_fstest auto quick
>> +
>> +_require_scratch
>> +_require_command "$F2FS_INJECT_PROG" inject.f2fs
>> +
>> +_fixed_by_git_commit f2fs-tools 958cd6e
>                                            ^^^^^^^^
>                                            commit subject?
> 
>> +
>> +filename=$SCRATCH_MNT/foo
>> +hardlink=$SCRATCH_MNT/bar
>> +
>> +for ((i=0;i<14;i++)) do
>> +	echo "round: " $i >> $seqres.full
>> +
>> +	_scratch_mkfs "-f" >> $seqres.full
> 
> As you've add "-f" in _scratch_mkfs, so this "-f" can be removed.
> 
>> +	_scratch_mount >> $seqres.full
>                           ^^^^^^
>                           I think it's useless
> 
>> +
>> +	if [ $i == 0 ]; then
>> +		touch $filename
>> +		ino=`stat -c '%i' $filename`
>> +		nlink=0
>> +	elif [ $i == 1 ]; then
>> +		mkdir $filename
>> +		ino=`stat -c '%i' $filename`
>> +		nlink=1
>> +	elif [ $i == 2 ]; then
>> +		mknod $filename c 9 0
>> +		ino=`stat -c '%i' $filename`
>> +		nlink=0
>> +	elif [ $i == 3 ]; then
>> +		mknod $filename b 8 0
>> +		ino=`stat -c '%i' $filename`
>> +		nlink=0
>> +	elif [ $i == 4 ]; then
>> +		mkfifo $filename
>> +		ino=`stat -c '%i' $filename`
>> +		nlink=0
>> +	elif [ $i == 5 ]; then
>> +		socket -s $filename >> $seqres.full 2>&1 &
>                 ^^^^^^
> 
> Where's the "socket" command from? I think it's not always installed on any
> Linux system. fstests never use this command in any test case. If you
> need this command, you might need to check that, and _notrun if it's
> not installed.
> 
>> +		pid=$!
> 
> As you have background processes in this test case, you need to make sure
> these processes are killed properly in _cleanup, especially if the test
> is killed suddently, refer to generic/019.

Zorro, I've updated the patchset, could you please help to check that?

Thanks,

> 
> Thanks,
> Zorro
> 
>> +		sleep 2
>> +		ino=`stat -c '%i' $filename`
>> +		kill $pid >> $seqres.full 2>&1
>> +		nlink=0
>> +	elif [ $i == 6 ]; then
>> +		ln -s $SCRATCH_MNT/empty $filename
>> +		ino=`stat -c '%i' $filename`
>> +		nlink=0
>> +	elif [ $i == 7 ]; then
>> +		# orphan inode
>> +		touch $filename
>> +		ino=`stat -c '%i' $filename`
>> +		$F2FS_IO_PROG write 1 0 1 zero atomic_commit $filename 5000 >> $seqres.full 2>&1 &
>> +		stat $filename >> $seqres.full
>> +		rm $filename
>> +		$F2FS_IO_PROG shutdown 1 $SCRATCH_MNT/ >> $seqres.full
>> +		sleep 6
>> +		nlink=1
>> +	elif [ $i == 8 ]; then
>> +		# hardlink on file
>> +		touch $filename
>> +		ino=`stat -c '%i' $filename`
>> +		ln $filename $hardlink
>> +		nlink=0
>> +	elif [ $i == 9 ]; then
>> +		# hardlink on charactor
>> +		mknod $filename c 9 0
>> +		ino=`stat -c '%i' $filename`
>> +		ln $filename $hardlink
>> +		nlink=0
>> +	elif [ $i == 10 ]; then
>> +		# hardlink on blockdev
>> +		mknod $filename b 8 0
>> +		ino=`stat -c '%i' $filename`
>> +		ln $filename $hardlink
>> +		nlink=0
>> +	elif [ $i == 11 ]; then
>> +		# hardlink on pipe
>> +		mkfifo $filename
>> +		ino=`stat -c '%i' $filename`
>> +		ln $filename $hardlink
>> +		nlink=0
>> +	elif [ $i == 12 ]; then
>> +		# hardlink on socket
>> +		socket -s $filename >> $seqres.full 2>&1 &
>> +		pid=$!
>> +		sleep 2
>> +		ino=`stat -c '%i' $filename`
>> +		kill $pid >> $seqres.full 2>&1
>> +		ln $filename $hardlink
>> +		nlink=0
>> +	elif [ $i == 13 ]; then
>> +		# hardlink on symlink
>> +		ln -s $SCRATCH_MNT/empty $filename
>> +		ino=`stat -c '%i' $filename`
>> +		ln $filename $hardlink
>> +		nlink=0
>> +	fi
>> +
>> +	if [ $i != 7 ]; then
>> +		stat $SCRATCH_MNT/* >> $seqres.full
>> +	fi
>> +	echo "ino:"$ino >> $seqres.full
>> +	echo "nlink:"$nlink >> $seqres.full
>> +
>> +	_scratch_unmount
>> +
>> +	$F2FS_INJECT_PROG --node --mb i_links --nid $ino --val $nlink $SCRATCH_DEV \
>> +		>> $seqres.full || _fail "fail to inject"
>> +
>> +	export FSCK_OPTIONS="--dry-run"
>> +	_check_scratch_fs >>$seqres.full 2>&1 && _fail "can't find corruption"
>> +	_repair_scratch_fs >> $seqres.full
>> +	_check_scratch_fs
>> +
>> +	_scratch_mount
>> +	_scratch_unmount
>> +done
>> +
>> +echo "Silence is golden"
>> +
>> +status=0
>> +exit
>> diff --git a/tests/f2fs/009.out b/tests/f2fs/009.out
>> new file mode 100644
>> index 00000000..7e977155
>> --- /dev/null
>> +++ b/tests/f2fs/009.out
>> @@ -0,0 +1,2 @@
>> +QA output created by 009
>> +Silence is golden
>> -- 
>> 2.48.1
>>
>