linux-kernel - Re: [PATCH 03/16] vfs: don't evict uninitialized inode

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Message-ID: <CAOssrKfmR0beT4dXjg1dn6DBsPbmGBpS5xHpG9QtAAEgMWo_Xg@mail.gmail.com>
Date:   Mon, 30 Jul 2018 09:41:33 +0200
From:   Miklos Szeredi <mszeredi@...hat.com>
To:     Amir Goldstein <amir73il@...il.com>
Cc:     Al Viro <viro@...iv.linux.org.uk>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Greg KH <gregkh@...uxfoundation.org>
Subject: Re: [PATCH 03/16] vfs: don't evict uninitialized inode

On Mon, Jul 30, 2018 at 7:09 AM, Amir Goldstein <amir73il@...il.com> wrote:
> On Mon, Jul 30, 2018 at 1:04 AM, Al Viro <viro@...iv.linux.org.uk> wrote:
>> From: Miklos Szeredi <mszeredi@...hat.com>
>>
>> iput() ends up calling ->evict() on new inode, which is not yet initialized
>> by owning fs.  So use destroy_inode() instead.
>>
>> Add to sb->s_inodes list only if inode is not in I_CREATING state (meaning
>> that it wasn't allocated with new_inode(), which already does the
>> insertion).
>>
>> Reported-by: Al Viro <viro@...iv.linux.org.uk>
>> Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
>> Fixes: 80ea09a002bf ("vfs: factor out inode_insert5()")
>
> Backport hint: this patch depends on the patch ("new primitive:
> discard_new_inode()") currently commit 22dc9a168272 in Al's for-next.
>
> Still trying to figure out the best format to channel this information to
> stable maintainers...

Why are we talking about stable?  This regression was introduced in
4.18-rc1, spotted by Al *and* reported by testers.  It needs to be
fixed in one way or other in 4.18.

I've nothing against applying "new primitive: discard_new_inode() now
+ this patch, but if it is deemed too risky at this point, we could
just revert the buggy commit 80ea09a002bf ("vfs: factor out
inode_insert5()") and its dependencies.

Thanks,
Miklos