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

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Date:   Sun, 14 Jan 2018 21:50:50 +0900
From:   OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:     ChenGuanqiao <chen.chenchacha@...mail.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 2/3] fs: fat: Add volume label entry method function

ChenGuanqiao <chen.chenchacha@...mail.com> writes:

> Signed-off-by: ChenGuanqiao <chen.chenchacha@...mail.com>
> ---
>  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;

Now, dir is always root, so this check doesn't matter.

> +	*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;

Here is too. dir is always root.

> +	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);

-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>