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SubjectRe: [PATCH 3/3] fs: fat: add ioctl method in fat filesystem driver
Date
ChenGuanqiao <chen.chenchacha@foxmail.com> writes:

> +static int fat_check_d_characters(char *label, unsigned long len)
> +{
> + int i;
> +
> + for (i = 0; i < len; ++i) {
> + switch (label[i]) {
> + case 'a' ... 'z':
> + label[i] = __toupper(label[i]);
> + case 'A' ... 'Z':
> + case '0' ... '9':
> + case '_':
> + case 0x20:
> + continue;
> + default:
> + return -EINVAL;
> + }

Same question with previous though, what windows do if label = "a b c"?
(this is including space other than end of name or extension.)

> + }
> +
> + return 0;
> +}

> +static int fat_ioctl_set_volume_label(struct file *file,
> + u8 __user *vol_label)
> +{
> + int err = 0;
> + u8 label[MSDOS_NAME];
> + struct timespec ts;
> + struct buffer_head *boot_bh;
> + struct buffer_head *vol_bh;
> + struct msdos_dir_entry *de;
> + struct fat_boot_sector *b;
> + struct inode *inode = file_inode(file);
> + struct super_block *sb = inode->i_sb;
> + struct msdos_sb_info *sbi = MSDOS_SB(sb);
> +

[...]

> + err = mnt_want_write_file(file);
> + if (err)
> + goto out;
> +
> + down_write(&sb->s_umount);

Looks like inode_lock() for rootdir is gone. It is necessary to
traverse+modify.

> + /* Updates root directory's vol_label */
> + err = fat_get_volume_label_entry(inode, &vol_bh, &de);
> + ts = current_time(inode);
> + if (err) {
> + /* Create volume label entry */
> + err = fat_add_volume_label_entry(inode, label, &ts);
> + if (err)
> + goto out_vol_brelse;
> + } else {
> + /* Write to root directory */
> + memcpy(de->name, label, sizeof(de->name));
> + inode->i_ctime = inode->i_mtime = inode->i_atime = ts;
> +
> + mark_buffer_dirty(vol_bh);
> + }
> +
> + /* Update sector's vol_label */
> + boot_bh = sb_bread(sb, 0);
> + if (boot_bh == NULL) {
> + fat_msg(sb, KERN_ERR,
> + "unable to read boot sector to write volume label");
> + err = -EIO;
> + goto out_boot_brelse;
> + }
> +
> + b = (struct fat_boot_sector *)boot_bh->b_data;
> + if (sbi->fat_bits == 32)
> + memcpy(b->fat32.vol_label, label, sizeof(label));
> + else
> + memcpy(b->fat16.vol_label, label, sizeof(label));
> +
> + mark_buffer_dirty(boot_bh);
> +
> + /* Synchronize the data together */
> + err = sync_dirty_buffer(boot_bh);
> + if (err)
> + goto out_boot_brelse;
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

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