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From: Christoph Hellwig <hch@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Sascha Hauer <s.hauer@pengutronix.de>,
	Christoph Hellwig <hch@infradead.org>,
	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: Mon, 25 Jan 2021 20:42:49 +0000	[thread overview]
Message-ID: <20210125204249.GA1103662@infradead.org> (raw)
In-Reply-To: <20210125154507.GH1175@quack2.suse.cz>

On Mon, Jan 25, 2021 at 04:45:07PM +0100, Jan Kara wrote:
> > What do you mean by "take"? Take the superblock as an argument to
> > quotactl_sb() or take a reference to the superblock?
> > Sorry, I don't really get where you aiming at.
> 
> I think Christoph was pointing at the fact it is suboptimal to search for
> superblock by device number when you already have a pointer to it.  And I
> guess he was suggesting we could pass 'sb' pointer to quotactl_sb() when we
> already have it. Although to be honest, I'm not sure how Christoph imagines
> the refactoring of user_get_super() he mentions - when we have a path
> looked up through user_path(), that pins the superblock the path is on so
> it cannot be unmounted. So perhaps quotactl_sb() can done like:

I don't think we need a quotactl_sb at all, do_quotactl is in fact a
pretty good abstraction as-is.

For the path based one we just need to factor out a little helper
to set excl and thaw and then call it like:

	sb = path.dentry->d_inode->i_sb;

	if (excl)
		down_write(&sb->s_umount);
	else
		down_read(&sb->s_umount);
	if (thawed && sb->s_writers.frozen != SB_UNFROZEN)
		ret = -EBUSY;
	else
		ret = do_quotactl(sb, type, cmds, id, addr, &path);
	if (excl)
		up_write(&sb->s_umount);
	else
		up_read(&sb->s_umount);

as there is no good reason to bring over the somewhat strange wait until
unfrozen semantics to a new syscall.

  reply	other threads:[~2021-01-25 20:47 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
2021-01-25  8:38     ` Sascha Hauer
2021-01-25 15:45       ` Jan Kara
2021-01-25 20:42         ` Christoph Hellwig [this message]
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

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