Re: [PATCH v27 04/10] fs/ntfs3: Add file operations and implementation

[Kari Argillander <kari.argillander@gmail.com>]

On Sun, Aug 22, 2021 at 02:20:03PM +0200, Pali Rohár wrote:
> On Thursday 29 July 2021 16:49:37 Konstantin Komarov wrote:
> > diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
> > new file mode 100644
> > index 000000000..b4369c61a
> > --- /dev/null
> > +++ b/fs/ntfs3/file.c
> > @@ -0,0 +1,1130 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + *
> > + * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
> > + *
> > + *  regular file handling primitives for ntfs-based filesystems
> > + */
> > +#include <linux/backing-dev.h>
> > +#include <linux/buffer_head.h>
> > +#include <linux/compat.h>
> > +#include <linux/falloc.h>
> > +#include <linux/fiemap.h>
> > +#include <linux/msdos_fs.h> /* FAT_IOCTL_XXX */
> > +#include <linux/nls.h>
> > +
> > +#include "debug.h"
> > +#include "ntfs.h"
> > +#include "ntfs_fs.h"
> > +
> > +static int ntfs_ioctl_fitrim(struct ntfs_sb_info *sbi, unsigned long arg)
> > +{
> > +	struct fstrim_range __user *user_range;
> > +	struct fstrim_range range;
> > +	struct request_queue *q = bdev_get_queue(sbi->sb->s_bdev);
> > +	int err;
> > +
> > +	if (!capable(CAP_SYS_ADMIN))
> > +		return -EPERM;
> > +
> > +	if (!blk_queue_discard(q))
> > +		return -EOPNOTSUPP;
> > +
> > +	user_range = (struct fstrim_range __user *)arg;
> > +	if (copy_from_user(&range, user_range, sizeof(range)))
> > +		return -EFAULT;
> > +
> > +	range.minlen = max_t(u32, range.minlen, q->limits.discard_granularity);
> > +
> > +	err = ntfs_trim_fs(sbi, &range);
> > +	if (err < 0)
> > +		return err;
> > +
> > +	if (copy_to_user(user_range, &range, sizeof(range)))
> > +		return -EFAULT;
> > +
> > +	return 0;
> > +}
> > +
> > +static long ntfs_ioctl(struct file *filp, u32 cmd, unsigned long arg)
> > +{
> > +	struct inode *inode = file_inode(filp);
> > +	struct ntfs_sb_info *sbi = inode->i_sb->s_fs_info;
> > +	u32 __user *user_attr = (u32 __user *)arg;
> > +
> > +	switch (cmd) {
> > +	case FAT_IOCTL_GET_ATTRIBUTES:
> > +		return put_user(le32_to_cpu(ntfs_i(inode)->std_fa), user_attr);
> > +
> > +	case FAT_IOCTL_GET_VOLUME_ID:
> > +		return put_user(sbi->volume.ser_num, user_attr);
> > +
> > +	case FITRIM:
> > +		return ntfs_ioctl_fitrim(sbi, arg);
> > +	}
> > +	return -ENOTTY; /* Inappropriate ioctl for device */
> > +}
> 
> Hello! What with these two FAT_* ioctls in NTFS code? Should NTFS driver
> really implements FAT ioctls? Because they looks like some legacy API
> which is even not implemented by current ntfs.ko driver.

I was looking same thing when doing new ioctl for shutdown. These
should be dropped completly before this gets upstream. Then we have
more time to think what ioctl calls should used and which are
necessarry.

> Specially, should FS driver implements ioctl for get volume id which in
> this way? Because basically every fs have some kind of uuid / volume id
> and they can be already retrieved by appropriate userspace tool.

My first impression when looking this code was that this is just copy
paste work from fat driver. FITRIM is exactly the same. Whoever
copyed it must have not thinked this very closly. Good thing you
bringing this up.

I didn't want to just yet because there is quite lot messages and
things which are in Komarov todo list. Hopefully radio silence will
end soon. I'm afraid next message will be "Please pull" for Linus
and then it cannot happend because of radio silence.