[PATCH v7 2/3] fs: fat: Add volume label entry method function

[ChenGuanqiao]

Signed-off-by: ChenGuanqiao <chen.chenchacha@xxxxxxxxxxx>
---
 fs/fat/dir.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 8e100c3bf72c..53f36c03760e 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -881,6 +881,59 @@ static int fat_get_short_entry(struct inode *dir, loff_t *pos,
	return -ENOENT;
 }

+int fat_get_volume_label_entry(struct inode *dir, struct buffer_head **bh,
+			       struct msdos_dir_entry **de)
+{
+	loff_t pos = 0;
+
+	if (dir->i_ino != MSDOS_ROOT_INO)
+		return -EFAULT;
+
+	*bh = NULL;
+	*de = NULL;
+	while (fat_get_entry(dir, &pos, bh, de) >= 0) {
+		if (((*de)->attr & ATTR_VOLUME) && ((*de)->attr != ATTR_EXT) &&
+		    !IS_FREE((*de)->name))
+			return 0;
+	}
+	return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(fat_get_volume_label_entry);
+
+int fat_add_volume_label_entry(struct inode *dir, const unsigned char *name,
+			       struct timespec *ts)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
+	struct msdos_dir_entry de;
+	struct fat_slot_info sinfo;
+	__le16 time, date;
+	int err;
+
+	if (dir->i_ino != MSDOS_ROOT_INO)
+		return -EFAULT;
+
+	memcpy(de.name, name, MSDOS_NAME);
+	de.attr = ATTR_VOLUME;
+	de.lcase = 0;
+	fat_time_unix2fat(sbi, ts, &time, &date, NULL);
+	de.cdate = de.adate = 0;
+	de.ctime = 0;
+	de.ctime_cs = 0;
+	de.time = time;
+	de.date = date;
+	fat_set_start(&de, 0);
+	de.size = 0;
+
+	err = fat_add_entries(dir, &de, 1, &sinfo);
+	if (err)
+		return err;
+
+	brelse(sinfo.bh);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fat_add_volume_label_entry);
+
 /*
  * The ".." entry can not provide the "struct fat_slot_info" information
  * for inode, nor a usable i_pos. So, this function provides some information
--
2.11.0