lkml.org 
[lkml]   [2018]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 3/3] fs: fat: add ioctl method in fat filesystem driver
+Cc: Pali, who AFAIRC is interested in FAT labeling mess.

On Wed, Jan 17, 2018 at 12:43 PM, ChenGuanqiao
<chen.chenchacha@foxmail.com> wrote:

Commit message?

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

> #include <linux/fsnotify.h>
> #include <linux/security.h>
> #include <linux/falloc.h>
> +#include <linux/ctype.h>

It would be better to squeeze it to have order (to some extent) preserved.

> +static int fat_check_d_characters(char *label, unsigned long len)
> +{
> + int i;
> +
> + for (i = 0; i < len; ++i) {

Oy vey, unsigned long len vs. int i.

> + switch (label[i]) {
> + case 'a' ... 'z':
> + label[i] = __toupper(label[i]);
> + case 'A' ... 'Z':
> + case '0' ... '9':
> + case '_':
> + case 0x20:
> + continue;

I'm not sure this is best approach. And since there is no commit
message I can't be constructive.

> + default:
> + return -EINVAL;
> + }
> + }
> +
> + return 0;
> +}

> +static int fat_ioctl_get_volume_label(struct inode *inode,
> + u8 __user *vol_label)
> +{

> + int err = 0;

Redundant assignment.

> + struct buffer_head *bh;
> + struct msdos_dir_entry *de;
> + struct super_block *sb = inode->i_sb;

Moreover, perhaps reversed tree order for the definition block?

> +
> + inode = d_inode(sb->s_root);
> + inode_lock_shared(inode);
> +
> + err = fat_get_volume_label_entry(inode, &bh, &de);
> + if (err)
> + goto out;
> +
> + if (copy_to_user(vol_label, de->name, MSDOS_NAME))
> + err = -EFAULT;
> +
> + brelse(bh);
> +out:
> + inode_unlock_shared(inode);
> +
> + return err;
> +}
> +

> +static int fat_ioctl_set_volume_label(struct file *file,
> + u8 __user *vol_label)

Perhaps vol_label -> label, and fit one line?

> +{
> + 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);
> +
> + inode = d_inode(sb->s_root);
> +
> + if (copy_from_user(label, vol_label, sizeof(label))) {
> + err = -EFAULT;
> + goto out;
> + }
> +
> + err = fat_check_d_characters(label, sizeof(label));
> + if (err)
> + goto out;
> +
> + err = mnt_want_write_file(file);
> + if (err)
> + goto out;
> +
> + down_write(&sb->s_umount);
> +
> + /* 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;
> +
> +out_boot_brelse:
> + brelse(boot_bh);
> +out_vol_brelse:
> + brelse(vol_bh);
> +
> + up_write(&sb->s_umount);
> + mnt_drop_write_file(file);
> +out:
> + return err;
> +}



--
With Best Regards,
Andy Shevchenko

\
 
 \ /
  Last update: 2018-01-29 14:19    [W:0.166 / U:4.596 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site