From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Gwendal Grignou <gwendal@chromium.org>,
dlunev@chromium.org
Subject: Re: [PATCH] fat: ignore .. subdir and always add a link to dirs
Date: Wed, 13 Mar 2024 20:06:41 +0900 [thread overview]
Message-ID: <874jdajsqm.fsf@mail.parknet.co.jp> (raw)
In-Reply-To: <ZfFmvGRlNR4ZiMMC@quatroqueijos.cascardo.eti.br> (Thadeu Lima de Souza Cascardo's message of "Wed, 13 Mar 2024 05:41:32 -0300")
Thadeu Lima de Souza Cascardo <cascardo@igalia.com> writes:
>> So you break the mkdir/rmdir link counting, isn't it?
>>
>
> It is off by one on those images with directories without ".." subdir.
> Otherwise, everything else works fine. mkdir/rmdir inside such directories work
> without any issues as rmdir that same directory.
mkdir() increase link count, rmdir decrease link count. Your change set
a dir link count always 2? So if there are 3 normal subdirs, and rmdir
all those normal dirs, link count underflow.
Thanks.
> If, on the other hand, we left everything as is and only skipped the
> validation, such directories would be created with a link count of 0. Then,
> doing a mkdir inside them would crash the kernel with a BUG as we cannot
> increment the link count of an inode with 0 links.
>
> So the idea of the fix here is that, independently of the existence of "..",
> the link count will always be at least 1.
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
next prev parent reply other threads:[~2024-03-13 11:06 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-22 20:30 [PATCH] fat: ignore .. subdir and always add a link to dirs Thadeu Lima de Souza Cascardo
2024-02-23 1:52 ` OGAWA Hirofumi
2024-02-23 2:02 ` Thadeu Lima de Souza Cascardo
2024-02-23 8:27 ` OGAWA Hirofumi
2024-02-23 8:32 ` OGAWA Hirofumi
2024-02-23 9:58 ` Thadeu Lima de Souza Cascardo
2024-02-23 12:29 ` OGAWA Hirofumi
2024-02-23 13:16 ` Thadeu Lima de Souza Cascardo
2024-02-23 13:33 ` Thadeu Lima de Souza Cascardo
2024-02-28 1:42 ` Thadeu Lima de Souza Cascardo
2024-02-28 3:38 ` OGAWA Hirofumi
2024-02-28 9:10 ` Thadeu Lima de Souza Cascardo
2024-03-04 23:37 ` Thadeu Lima de Souza Cascardo
2024-03-05 4:14 ` OGAWA Hirofumi
2024-03-10 5:52 ` OGAWA Hirofumi
2024-03-10 10:14 ` Thadeu Lima de Souza Cascardo
2024-03-10 14:59 ` OGAWA Hirofumi
2024-03-13 7:58 ` Thadeu Lima de Souza Cascardo
2024-03-13 8:05 ` OGAWA Hirofumi
2024-03-13 8:41 ` Thadeu Lima de Souza Cascardo
2024-03-13 11:06 ` OGAWA Hirofumi [this message]
2024-03-13 11:16 ` Thadeu Lima de Souza Cascardo
2024-03-13 12:43 ` OGAWA Hirofumi
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