linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Christoph Hellwig <hch@infradead.org>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: linux-fsdevel@vger.kernel.org,
	Richard Weinberger <richard@nod.at>,
	linux-mtd@lists.infradead.org, kernel@pengutronix.de,
	Jan Kara <jack@suse.com>
Subject: Re: [PATCH 1/8] quota: Allow to pass mount path to quotactl
Date: Fri, 22 Jan 2021 17:16:58 +0000	[thread overview]
Message-ID: <20210122171658.GA237653@infradead.org> (raw)
In-Reply-To: <20210122151536.7982-2-s.hauer@pengutronix.de>

On Fri, Jan 22, 2021 at 04:15:29PM +0100, Sascha Hauer wrote:
> This patch introduces the Q_PATH flag to the quotactl cmd argument.
> When given, the path given in the special argument to quotactl will
> be the mount path where the filesystem is mounted, instead of a path
> to the block device.
> This is necessary for filesystems which do not have a block device as
> backing store. Particularly this is done for upcoming UBIFS support.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

I hate overloading quotactl even more.  Why not add a new quotactl_path
syscall instead?

> +static struct super_block *quotactl_sb(dev_t dev, int cmd)
>  {
>  	struct super_block *sb;
>  	bool excl = false, thawed = false;
>  
>  	if (quotactl_cmd_onoff(cmd)) {
>  		excl = true;
> @@ -901,12 +887,50 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
>  		goto retry;
>  	}
>  	return sb;
> +}
> +
> +/*
> + * look up a superblock on which quota ops will be performed
> + * - use the name of a block device to find the superblock thereon
> + */
> +static struct super_block *quotactl_block(const char __user *special, int cmd)
> +{
> +#ifdef CONFIG_BLOCK
> +	struct filename *tmp = getname(special);
> +	int error;
> +	dev_t dev;
>  
> +	if (IS_ERR(tmp))
> +		return ERR_CAST(tmp);
> +	error = lookup_bdev(tmp->name, &dev);
> +	putname(tmp);
> +	if (error)
> +		return ERR_PTR(error);
> +
> +	return quotactl_sb(dev, cmd);
>  #else
>  	return ERR_PTR(-ENODEV);
>  #endif

Normal kernel style would be to keep the ifdef entirely outside the
function.

> +static struct super_block *quotactl_path(const char __user *special, int cmd)
> +{
> +	struct super_block *sb;
> +	struct path path;
> +	int error;
> +
> +	error = user_path_at(AT_FDCWD, special, LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT,
> +			   &path);

This adds an overly long line.

> +	if (error)
> +		return ERR_PTR(error);
> +
> +	sb = quotactl_sb(path.mnt->mnt_sb->s_dev, cmd);

I think quotactl_sb should take the superblock directly.  This will
need a little refactoring of user_get_super, but will lead to much
better logic.

  reply	other threads:[~2021-01-22 17:24 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-22 15:15 [PATCH v5 0/8] Add quota support to UBIFS Sascha Hauer
2021-01-22 15:15 ` [PATCH 1/8] quota: Allow to pass mount path to quotactl Sascha Hauer
2021-01-22 17:16   ` Christoph Hellwig [this message]
2021-01-25  8:38     ` Sascha Hauer
2021-01-25 15:45       ` Jan Kara
2021-01-25 20:42         ` Christoph Hellwig
2021-01-26 13:17           ` Jan Kara
2021-01-26 13:34             ` Christoph Hellwig
2021-01-26 16:18               ` Jan Kara
2021-01-27 14:05                 ` Sascha Hauer
2021-01-27 14:19                   ` Jan Kara
2021-01-26 10:45         ` Sascha Hauer
2021-01-27 14:46           ` Jan Kara
2021-01-27 16:25             ` Christoph Hellwig
2021-01-22 15:15 ` [PATCH 2/8] ubifs: move checks and preparation into setflags() Sascha Hauer
2021-01-22 15:15 ` [PATCH 3/8] ubifs: Add support for FS_IOC_FS[SG]ETXATTR ioctls Sascha Hauer
2021-01-22 17:18   ` Christoph Hellwig
2021-01-22 15:15 ` [PATCH 4/8] ubifs: do not ubifs_inode() on potentially NULL pointer Sascha Hauer
2021-01-22 15:15 ` [PATCH 5/8] ubifs: Factor out ubifs_set_feature_flag() Sascha Hauer
2021-01-22 15:15 ` [PATCH 6/8] ubifs: Add support for project id Sascha Hauer
2021-01-22 15:15 ` [PATCH 7/8] ubifs: export get_znode Sascha Hauer
2021-01-22 17:20   ` Christoph Hellwig
2021-01-22 15:15 ` [PATCH 8/8] ubifs: Add quota support Sascha Hauer
  -- strict thread matches above, loose matches on Subject: below --
2020-01-24 13:13 [PATCH v4 0/8] Add quota support to UBIFS Sascha Hauer
2020-01-24 13:13 ` [PATCH 1/8] quota: Allow to pass mount path to quotactl Sascha Hauer
2020-01-27 10:45   ` Jan Kara
2020-01-28 10:06     ` Sascha Hauer
2020-01-28 11:41       ` Jan Kara
2020-01-29  1:29       ` Al Viro
2020-01-29 16:14         ` Jan Kara
2020-02-04 10:35         ` Sascha Hauer
2020-02-18  9:22           ` Jan Kara

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210122171658.GA237653@infradead.org \
    --to=hch@infradead.org \
    --cc=jack@suse.com \
    --cc=kernel@pengutronix.de \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-mtd@lists.infradead.org \
    --cc=richard@nod.at \
    --cc=s.hauer@pengutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).