From: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
To: Jan Kara <jack@suse.cz>
Cc: <mtk.manpages@gmail.com>, <linux-man@vger.kernel.org>
Subject: Re: [PATCH] quotactl.2: Add some details about Q_QUOTAON
Date: Thu, 24 Oct 2019 18:03:22 +0800 [thread overview]
Message-ID: <dcc9aac1-77f2-83bb-a4a1-5cc4623ecd58@cn.fujitsu.com> (raw)
In-Reply-To: <20191024095558.GL31271@quack2.suse.cz>
on 2019/10/24 17:55, Jan Kara wrote:
> On Thu 24-10-19 16:11:33, Yang Xu wrote:
>> For Q_QUOTAON, on old kernel we can use quotacheck -ug to
>> generate quota files. But in current kernel, we can also hide them
>> in system inodes and indicate them by using "quota" or project feature.
>>
>> For user or group quota, we can do as below(etc ext4):
>> mkfs.ext4 -F -o quota /dev/sda5
>> mount /dev/sda5 /mnt
>> quotactl(QCMD(Q_QUOTAON, USRQUOTA), /dev/sda5, QFMT_VFS_V0, NULL);
>>
>> For project quota, we can do as below(etc ext4)
>> mkfs.ext4 -F -o quota,project /dev/sda5
>> mount /dev/sda5 /mnt
>> quotactl(QCMD(Q_QUOTAON, PRJQUOTA), /dev/sda5, QFMT_VFS_V0, NULL);
>>
>> Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
>
> ...
>> The quota file must exist; it is normally created with the
>> .BR quotacheck (8)
>> -program.
>> +program. It also can been stored as hidden system inode. In this case, there
>> +are no visible quota files in filesystem and no need to use
>> +.BR quotacheck (8)
>> +program. This is indicated by 'quota' and 'project' features.
>> This operation requires privilege
>> .RB ( CAP_SYS_ADMIN ).
>> .TP 8
>
> This is a good clarification. Thanks! I'd just somewhat expand this like:
>
> Quota information can be also stored in hidden system inodes for ext4, xfs,
> and other filesystems if the filesystem is configured so. In this case,
> there are no visible quota files and there is no need to use quotacheck(8).
> Quota information is always kept consistent by the filesystem and Q_QUOTAON
> quotactl only enables enforcement of quota limits. The presence of hidden
> system inodes with quota information is indicated by DQF_SYS_FILE flag in
> Q_GETINFO output.
Good. It is very professional.
>
>> @@ -638,7 +641,8 @@ The
>> .I id
>> argument is ignored.
>> .TP
>> -.B Q_XQUOTARM
>> +.B Q_XQUOTARM (Since linux 3.16)
>> +.\" 9da93f9b7cdf8ab28da6b364cdc1fafc8670b4dc
>
> Not sure if we need to specify commit ID here...
It is only a supplementary explanation. Other flag has similar id
message such as Q_XGETNEXTQUOTA in quotactl.2
------
.BR Q_XGETNEXTQUOTA " (since Linux 4.6)"
.\" commit 8b37524962b9c54423374717786198f5c0820a28
------
So, I think it is no problem.
>
> Honza
>
next prev parent reply other threads:[~2019-10-24 10:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-24 8:11 [PATCH] quotactl.2: Add some details about Q_QUOTAON Yang Xu
2019-10-24 9:55 ` Jan Kara
2019-10-24 10:03 ` Yang Xu [this message]
2019-10-25 6:06 ` [PATCH v2] " Yang Xu
2019-10-31 6:04 ` Michael Kerrisk (man-pages)
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