Re: [PATCH v2 11/20] btrfs: disable various operations on encrypted inodes

From: David Sterba <dsterba@suse.cz>
To: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>,
	Jaegeuk Kim <jaegeuk@kernel.org>,
	Eric Biggers <ebiggers@kernel.org>, Chris Mason <clm@fb.com>,
	Josef Bacik <josef@toxicpanda.com>,
	David Sterba <dsterba@suse.com>,
	linux-fscrypt@vger.kernel.org, linux-btrfs@vger.kernel.org,
	kernel-team@fb.com, Omar Sandoval <osandov@osandov.com>
Subject: Re: [PATCH v2 11/20] btrfs: disable various operations on encrypted inodes
Date: Wed, 7 Sep 2022 22:11:34 +0200	[thread overview]
Message-ID: <20220907201133.GJ32411@twin.jikos.cz> (raw)
In-Reply-To: <927dbeab576537ac0e4c954a8c3d13b148cd6a26.1662420176.git.sweettea-kernel@dorminy.me>

On Mon, Sep 05, 2022 at 08:35:26PM -0400, Sweet Tea Dorminy wrote:
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -1895,7 +1895,7 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
>  		goto relock;
>  	}
>  
> -	if (check_direct_IO(fs_info, from, pos)) {
> +	if (IS_ENCRYPTED(inode) || check_direct_IO(fs_info, from, pos)) {

I'm not sure if we want the IS_ENCRYPTED as an explicit check or put it
to check_direct_IO, but probably to make it obvious that direct io does
not work with it a separate check is ok.

>  		btrfs_inode_unlock(inode, ilock_flags);
>  		goto buffered;
>  	}
> @@ -3729,7 +3729,7 @@ static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
>  	ssize_t read = 0;
>  	ssize_t ret;
>  
> -	if (fsverity_active(inode))
> +	if (IS_ENCRYPTED(inode) || fsverity_active(inode))

Yeah as we have something similar for verity.

>  		return 0;
>  
>  	if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 482c5b3d9e70..fea48c12a33a 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -409,7 +409,8 @@ static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 size,
>  	 * compressed) data fits in a leaf and the configured maximum inline
>  	 * size.
>  	 */
> -	if (size < i_size_read(&inode->vfs_inode) ||
> +	if (IS_ENCRYPTED(&inode->vfs_inode) ||
> +	    size < i_size_read(&inode->vfs_inode) ||
>  	    size > fs_info->sectorsize ||
>  	    data_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info) ||
>  	    data_len > fs_info->max_inline)
> diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c
> index 9acf47b11fe6..d22086e1cbc8 100644
> --- a/fs/btrfs/reflink.c
> +++ b/fs/btrfs/reflink.c
> @@ -805,6 +805,13 @@ static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in,
>  		ASSERT(inode_in->i_sb == inode_out->i_sb);
>  	}
>  
> +	/*
> +	 * Can only reflink encrypted files if both files are encrypted.
> +	 */

The comment fits on one line (and slight 80 chars overflow is ok).

> +	if (!fscrypt_have_same_policy(inode_in, inode_out)) {
> +		return -EINVAL;

Single statements don't need the { }

> +	}
> +