linux-kernel - RE: [f2fs-dev] [PATCH 3/4] f2fs crypto: check encryption for tmpfile

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Date:	Thu, 28 May 2015 18:20:05 +0800
From:	Chao Yu <chao2.yu@...sung.com>
To:	'Jaegeuk Kim' <jaegeuk@...nel.org>
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net
Subject: RE: [f2fs-dev] [PATCH 3/4] f2fs crypto: check encryption for tmpfile

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@...nel.org]
> Sent: Wednesday, May 20, 2015 8:43 AM
> To: linux-kernel@...r.kernel.org; linux-fsdevel@...r.kernel.org;
> linux-f2fs-devel@...ts.sourceforge.net
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 3/4] f2fs crypto: check encryption for tmpfile
> 
> This patch adds to check encryption for tmpfile in early stage.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> ---
>  fs/f2fs/namei.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index dded2b0..47066b0 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -531,6 +531,11 @@ static int __f2fs_tmpfile(struct inode *dir, struct dentry *dentry,
>  	}
> 
>  	f2fs_lock_op(sbi);
> +
> +	err = f2fs_get_encryption_info(dir);
> +	if (err)
> +		goto out;
> +
>  	err = acquire_orphan_inode(sbi);
>  	if (err)
>  		goto out;
> --
> 2.1.1

I can't find the original thread, so I reply here.
Merged patch in dev branch shows that our code is modified as below:

static int f2fs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
+	int err = f2fs_get_encryption_info(dir);
+	if (err)
+		return err;
+
 	return __f2fs_tmpfile(dir, dentry, mode, NULL);
 }

It seems that, if we try to make a temp file in an unencrypted dir, we will
always fail with -ENODATA in f2fs_get_encryption_info because encryption
context is not exist in xattr.

So we should check dir with f2fs_encrypted_inode() before
f2fs_get_encryption_info() to avoid that.

Thanks,

--
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