From: Richard Weinberger <richard.weinberger@gmail.com>
To: Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@infradead.org>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Dongsheng Yang <yangds.fnst@cn.fujitsu.com>,
Richard Weinberger <richard@nod.at>,
linux-mtd@lists.infradead.org, kernel@pengutronix.de,
Sascha Hauer <s.hauer@pengutronix.de>
Subject: Re: UBIFS quota support
Date: Wed, 23 Jan 2019 00:07:12 +0100 [thread overview]
Message-ID: <CAFLxGvyrNaq6ya9TNr-tdEEbV=qsi8qEko6R7oJ-DtkxPJMk0g@mail.gmail.com> (raw)
In-Reply-To: <20190110114448.vcx6w76ibmxwvlh3@pengutronix.de>
On Thu, Jan 10, 2019 at 12:45 PM Sascha Hauer <s.hauer@pengutronix.de> wrote:
>
> Hi all,
>
> I'm currently working on resurrecting the UBIFS quota patches posted back in
> 2015 by Dongsheng Yang, last posted here:
>
> http://lists.infradead.org/pipermail/linux-mtd/2015-September/061812.html
>
> First of all I think work stopped there, there is no newer UBIFS quota
> support I am missing, right?
>
> One problem with this series was that the quotactl systemcall expects a
> path to a block device. UBIFS doesn't work on a block device but on a
> character device instead.
> The solution in this series was to pass the path to the cdev in
> quotactl. A struct cdev * member was added to struct super_block which
> was used to identify the superblock for a given cdev. This approach was
> rejected by Christoph ("I don't think the cdev has any business in core
> VFS code."). Apart from that UBIFS can not only be mounted with a path
> to the character device (mount -t ubifs /dev/ubix_y /mnt) but also in
> the form ubix:volname (mount -t ubifs ubix:volname /mnt) in which case
> userspace doesn't have any valid path it could pass in quotactl.
>
> An idea out of this would be to allow to pass the mountpoint instead of
> the path to the block device in quotactl which would work with nfs or
> even tmpfs aswell. Would that be acceptable? Any other ideas?
*kind ping*
Jan, another thing Sascha and I are not sure about, what are the consistency
constraints of the quota file?
If I read the code correctly, quota just writes to the quota file and
assumes that
the file system makes sure about consistency. Either by fsck fixing the quota
file or having a data journal for the quota file.
In case of UBIFS where we have a data journal this should be doable.
Is it okay when the quota file has S_SYNC set?
--
Thanks,
//richard
WARNING: multiple messages have this Message-ID (diff)
From: Richard Weinberger <richard.weinberger@gmail.com>
To: Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@infradead.org>
Cc: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>,
Richard Weinberger <richard@nod.at>,
Sascha Hauer <s.hauer@pengutronix.de>,
linux-mtd@lists.infradead.org, kernel@pengutronix.de,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: UBIFS quota support
Date: Wed, 23 Jan 2019 00:07:12 +0100 [thread overview]
Message-ID: <CAFLxGvyrNaq6ya9TNr-tdEEbV=qsi8qEko6R7oJ-DtkxPJMk0g@mail.gmail.com> (raw)
In-Reply-To: <20190110114448.vcx6w76ibmxwvlh3@pengutronix.de>
On Thu, Jan 10, 2019 at 12:45 PM Sascha Hauer <s.hauer@pengutronix.de> wrote:
>
> Hi all,
>
> I'm currently working on resurrecting the UBIFS quota patches posted back in
> 2015 by Dongsheng Yang, last posted here:
>
> http://lists.infradead.org/pipermail/linux-mtd/2015-September/061812.html
>
> First of all I think work stopped there, there is no newer UBIFS quota
> support I am missing, right?
>
> One problem with this series was that the quotactl systemcall expects a
> path to a block device. UBIFS doesn't work on a block device but on a
> character device instead.
> The solution in this series was to pass the path to the cdev in
> quotactl. A struct cdev * member was added to struct super_block which
> was used to identify the superblock for a given cdev. This approach was
> rejected by Christoph ("I don't think the cdev has any business in core
> VFS code."). Apart from that UBIFS can not only be mounted with a path
> to the character device (mount -t ubifs /dev/ubix_y /mnt) but also in
> the form ubix:volname (mount -t ubifs ubix:volname /mnt) in which case
> userspace doesn't have any valid path it could pass in quotactl.
>
> An idea out of this would be to allow to pass the mountpoint instead of
> the path to the block device in quotactl which would work with nfs or
> even tmpfs aswell. Would that be acceptable? Any other ideas?
*kind ping*
Jan, another thing Sascha and I are not sure about, what are the consistency
constraints of the quota file?
If I read the code correctly, quota just writes to the quota file and
assumes that
the file system makes sure about consistency. Either by fsck fixing the quota
file or having a data journal for the quota file.
In case of UBIFS where we have a data journal this should be doable.
Is it okay when the quota file has S_SYNC set?
--
Thanks,
//richard
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2019-01-22 23:07 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 11:44 UBIFS quota support Sascha Hauer
2019-01-10 11:44 ` Sascha Hauer
2019-01-22 23:07 ` Richard Weinberger [this message]
2019-01-22 23:07 ` Richard Weinberger
2019-01-23 9:43 ` Sascha Hauer
2019-01-23 9:43 ` Sascha Hauer
2019-01-23 9:46 ` Richard Weinberger
2019-01-23 9:46 ` Richard Weinberger
2019-01-23 9:55 ` Sascha Hauer
2019-01-23 9:55 ` Sascha Hauer
2019-01-23 10:47 ` Richard Weinberger
2019-01-23 10:47 ` Richard Weinberger
2019-01-23 15:47 ` Jan Kara
2019-01-23 15:47 ` Jan Kara
2019-01-25 9:21 ` Sascha Hauer
2019-01-25 9:21 ` Sascha Hauer
2019-01-28 8:09 ` Christoph Hellwig
2019-01-28 8:09 ` Christoph Hellwig
2019-01-30 12:45 ` Jan Kara
2019-01-30 12:45 ` Jan Kara
2019-01-31 7:37 ` Sascha Hauer
2019-01-31 7:37 ` Sascha Hauer
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