Date:   Fri, 10 Dec 2021 22:55:10 +0300 (MSK)
From:   Roman Anufriev <dotdot@yandex-team.ru>
To:     "Theodore Y. Ts'o" <tytso@mit.edu>
cc:     david@fromorbit.com, adilger@dilger.ca, linux-ext4@vger.kernel.org,
        jack@suse.cz, wshilong@ddn.com, dmtrmonakhov@yandex-team.ru,
        darrick.wong@oracle.com
Subject: Re: [PATCH] ext4: compare inode's i_projid with EXT4_DEF_PROJID
 rather than check EXT4_INODE_PROJINHERIT flag
In-Reply-To: <Ya+3L3gBFCeWZki7@mit.edu>
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References: <1638883122-8953-1-git-send-email-dotdot@yandex-team.ru> <alpine.OSX.2.23.453.2112071702150.70498@dotdot-osx> <Ya+3L3gBFCeWZki7@mit.edu>
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On Tue, 7 Dec 2021, Theodore Y. Ts'o wrote:

> On Tue, Dec 07, 2021 at 05:05:19PM +0300, Roman Anufriev wrote:
>>> Commit 7ddf79a10395 ("ext4: only set project inherit bit for directory")
>>> removes EXT4_INODE_PROJINHERIT flag from regular files. This makes
>>> ext4_statfs() output incorrect (function does not apply quota limits
>>> on used/available space, etc) when called on dentry of regular file
>>> with project quota enabled.
>
> Under what circumstance is userspace trying to call statfs on a file
> descriptor?
>
> Removing the test for EXT4_INODE_PROJINHERIT will cause
> incorrect/misleading results being returned in the case where we have
> a directory where a directory hierarchy is using project id's, but
> which is *not* using PROJINHERIT.

I'm not sure I quite understood what will be wrong in that case, because
as Dave mentioned:

> PROJINHERIT just indicates the default projid that an inode is
> created with; ...

 								Roman