linux-kernel - Re: [PATCH] ubifs: Fix O_TMPFILE corner case in ubifs

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Date:   Thu, 30 Mar 2017 11:10:27 +0200
From:   Ralph Sennhauser <ralph.sennhauser@...il.com>
To:     Amir Goldstein <amir73il@...il.com>
Cc:     Richard Weinberger <richard@....at>, linux-mtd@...ts.infradead.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Artem Bityutskiy <dedekind1@...il.com>,
        "stable [v4.9]" <stable@...r.kernel.org>
Subject: Re: [PATCH] ubifs: Fix O_TMPFILE corner case in ubifs_link()

On Thu, 30 Mar 2017 11:59:17 +0300
Amir Goldstein <amir73il@...il.com> wrote:

> On Thu, Mar 30, 2017 at 11:56 AM, Richard Weinberger <richard@....at>
> wrote:
> > It is perfectly fine to link a tmpfile back using linkat().
> > Since tmpfiles are created with a link count of 0 they appear
> > on the orphan list, upon re-linking the inode has to be removed
> > from the orphan list again.
> >  
> 
> Looks good.

Nothing to add.

Thanks to both of you.
Ralph

> 
> > Cc: <stable@...r.kernel.org>
> > Cc: Ralph Sennhauser <ralph.sennhauser@...il.com>
> > Cc: Amir Goldstein <amir73il@...il.com  
> 
> typo: missing closing >
> 
> > Reported-by: Ralph Sennhauser <ralph.sennhauser@...il.com>
> > Tested-by: Ralph Sennhauser <ralph.sennhauser@...il.com>
> > Reported-by: Amir Goldstein <amir73il@...il.com  
> 
> and here too
> 
> > Fixes: 474b93704f321 ("ubifs: Implement O_TMPFILE")
> > Signed-off-by: Richard Weinberger <richard@....at>
> > ---
> >  fs/ubifs/dir.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
> > index 0858213a4e63..0139155045fe 100644
> > --- a/fs/ubifs/dir.c
> > +++ b/fs/ubifs/dir.c
> > @@ -748,6 +748,11 @@ static int ubifs_link(struct dentry
> > *old_dentry, struct inode *dir, goto out_fname;
> >
> >         lock_2_inodes(dir, inode);
> > +
> > +       /* Handle O_TMPFILE corner case, it is allowed to link a
> > O_TMPFILE. */
> > +       if (inode->i_nlink == 0)
> > +               ubifs_delete_orphan(c, inode->i_ino);
> > +
> >         inc_nlink(inode);
> >         ihold(inode);
> >         inode->i_ctime = ubifs_current_time(inode);
> > --
> > 2.7.3
> >