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

From: Adrian Hunter
Date: Thu Mar 30 2017 - 05:37:59 EST


On 30/03/17 11:56, Richard Weinberger 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.
>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Cc: Ralph Sennhauser <ralph.sennhauser@xxxxxxxxx>
> Cc: Amir Goldstein <amir73il@xxxxxxxxx
> Reported-by: Ralph Sennhauser <ralph.sennhauser@xxxxxxxxx>
> Tested-by: Ralph Sennhauser <ralph.sennhauser@xxxxxxxxx>
> Reported-by: Amir Goldstein <amir73il@xxxxxxxxx
> Fixes: 474b93704f321 ("ubifs: Implement O_TMPFILE")
> Signed-off-by: Richard Weinberger <richard@xxxxxx>
> ---
> 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);

Isn't there also a deletion inode in the journal? If the recovery sees that
won't it delete the file data?