On Saturday 06 October 2018 16:33:10 chen.chenchacha wrote:
> On Thu, 2018-10-04 at 19:33 +0200, Pali Rohár wrote:
> > On Friday 05 October 2018 01:21:00 chenchacha wrote:
> > > Signed-off-by: chenchacha <chen.chencha...@foxmail.com>
> > > ---
> > > fs/fat/file.c | 22 ++++++++++++++++++++++
> > > include/uapi/linux/msdos_fs.h | 1 +
> > > 2 files changed, 23 insertions(+)
> > >
> > > diff --git a/fs/fat/file.c b/fs/fat/file.c
> > > index 4724cc9ad650..56db0b5a8df1 100644
> > > --- a/fs/fat/file.c
> > > +++ b/fs/fat/file.c
> > > @@ -121,10 +121,30 @@ static int fat_ioctl_get_volume_id(struct
> > > inode *inode, u32 __user *user_attr)
> > > return put_user(sbi->vol_id, user_attr);
> > > }
> > >
> > > +static int fat_ioctl_get_volume_label(struct inode *inode, u8
> > > __user *label)
> > > +{
> > > + struct super_block *sb = inode->i_sb;
> > > + struct inode *root_inode = d_inode(sb->s_root);
> > > + struct buffer_head *bh = NULL;
> > > + struct msdos_dir_entry *de;
> > > + int err;
> > > +
> > > + inode_lock_shared(root_inode);
> > > + err = fat_get_root_entry(root_inode, &bh, &de);
> > > + if (err == 0) {
> > > + if (copy_to_user(label, de->name, MSDOS_NAME))
> >
> > You need to convert entry name from 8.3 format to label in correct
> > encoding specified by codepage mount option. Plus needs to handle
> > leading 0x03 byte.
> >
> I think it might be better to put the decoder/encoder on the
> application layter.I do not think so. On all other places in msdos.ko and vfat.ko driver which communicate with userspace is that decoder/encoder active and user does not see raw bytes. It is really bad to mix encodings and API of different calls. If in mount option I specified that I want to use XYZ encoding, why driver does not going to respect it? > Similarly, the handle leading 0x03 byte is in the > write function. And make read operation pure, just to carry the volume > label in root directory to the user. > > What do you think, Pali? > -- Pali Rohár pali.ro...@gmail.com
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