[PATCH] ubifs: Fix O_TMPFILE corner case in ubifs_link()

[Amir Goldstein]

On Thu, Mar 30, 2017 at 11:56 AM, Richard Weinberger <richard at nod.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.

> Cc: <stable at vger.kernel.org>
> Cc: Ralph Sennhauser <ralph.sennhauser at gmail.com>
> Cc: Amir Goldstein <amir73il at gmail.com

typo: missing closing >

> Reported-by: Ralph Sennhauser <ralph.sennhauser at gmail.com>
> Tested-by: Ralph Sennhauser <ralph.sennhauser at gmail.com>
> Reported-by: Amir Goldstein <amir73il at gmail.com

and here too

> Fixes: 474b93704f321 ("ubifs: Implement O_TMPFILE")
> Signed-off-by: Richard Weinberger <richard at nod.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
>