f2fs: sysfs: add encoding_flags entry

This patch adds a new sysfs entry /sys/fs/f2fs/<disk>/encoding_flags,
it is a read-only entry to show the value of sb.s_encoding_flags, the
value is hexadecimal.

============================     ==========
Flag_Name                        Flag_Value
============================     ==========
SB_ENC_STRICT_MODE_FL            0x00000001
SB_ENC_NO_COMPAT_FALLBACK_FL     0x00000002
============================     ==========

case#1
mkfs.f2fs -f -O casefold -C utf8:strict /dev/vda
mount /dev/vda /mnt/f2fs
cat /sys/fs/f2fs/vda/encoding_flags
1

case#2
mkfs.f2fs -f -O casefold -C utf8 /dev/vda
fsck.f2fs --nolinear-lookup=1 /dev/vda
mount /dev/vda /mnt/f2fs
cat /sys/fs/f2fs/vda/encoding_flags
2

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 59adb7dc6f9efd89a8477f21086127cd058a43c6..1fa140da5a1ac359462a71a20b68366f8886521f 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -846,3 +846,16 @@ Description:       For several zoned storage devices, vendors will provide extra space
                reserved_blocks. However, it is not enough, since this extra space should
                not be shown to users. So, with this new sysfs node, we can hide the space
                by substracting reserved_blocks from total bytes.
+
+What:          /sys/fs/f2fs/<disk>/encoding_flags
+Date:          April 2025
+Contact:       "Chao Yu" <chao@kernel.org>
+Description:   This is a read-only entry to show the value of sb.s_encoding_flags, the
+               value is hexadecimal.
+
+               ============================     ==========
+               Flag_Name                        Flag_Value
+               ============================     ==========
+               SB_ENC_STRICT_MODE_FL            0x00000001
+               SB_ENC_NO_COMPAT_FALLBACK_FL     0x00000002
+               ============================     ==========

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 3a3485622691983717b3478380faefa839945fcc..cf98c5cbb98a8b07aacff7f6cfa3ca1edbcb2c9b 100644 (file)
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -274,6 +274,13 @@ static ssize_t encoding_show(struct f2fs_attr *a,
        return sysfs_emit(buf, "(none)\n");
 }
 
+static ssize_t encoding_flags_show(struct f2fs_attr *a,
+               struct f2fs_sb_info *sbi, char *buf)
+{
+       return sysfs_emit(buf, "%x\n",
+               le16_to_cpu(F2FS_RAW_SUPER(sbi)->s_encoding_flags));
+}
+
 static ssize_t mounted_time_sec_show(struct f2fs_attr *a,
                struct f2fs_sb_info *sbi, char *buf)
 {
@@ -1158,6 +1165,7 @@ F2FS_GENERAL_RO_ATTR(features);
 F2FS_GENERAL_RO_ATTR(current_reserved_blocks);
 F2FS_GENERAL_RO_ATTR(unusable);
 F2FS_GENERAL_RO_ATTR(encoding);
+F2FS_GENERAL_RO_ATTR(encoding_flags);
 F2FS_GENERAL_RO_ATTR(mounted_time_sec);
 F2FS_GENERAL_RO_ATTR(main_blkaddr);
 F2FS_GENERAL_RO_ATTR(pending_discard);
@@ -1270,6 +1278,7 @@ static struct attribute *f2fs_attrs[] = {
        ATTR_LIST(reserved_blocks),
        ATTR_LIST(current_reserved_blocks),
        ATTR_LIST(encoding),
+       ATTR_LIST(encoding_flags),
        ATTR_LIST(mounted_time_sec),
 #ifdef CONFIG_F2FS_STAT_FS
        ATTR_LIST(cp_foreground_calls),