[RFC ONLY 12/23] btrfs: disable various operations on encrypted inodes

From: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
To: Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
	David Sterba <dsterba@suse.com>,
	linux-btrfs@vger.kernel.org
Cc: Omar Sandoval <osandov@osandov.com>,
	Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Subject: [RFC ONLY 12/23] btrfs: disable various operations on encrypted inodes
Date: Wed, 13 Jul 2022 06:29:45 -0400	[thread overview]
Message-ID: <74b127c255c1c166acabd3db01acb1e85aa691a9.1657707687.git.sweettea-kernel@dorminy.me> (raw)
In-Reply-To: <cover.1657707686.git.sweettea-kernel@dorminy.me>

From: Omar Sandoval <osandov@osandov.com>

Initially, only normal data extents, using the normal (non-direct) IO
path, will be encrypted. This change forbids various other bits:
- allows reflinking only if both inodes have the same encryption status
- disables compressing encrypted inodes
- disables direct IO on encrypted inodes
- disable inline data on encrypted inodes

Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
---
 fs/btrfs/btrfs_inode.h | 3 +++
 fs/btrfs/file.c        | 4 ++--
 fs/btrfs/inode.c       | 3 ++-
 fs/btrfs/reflink.c     | 7 +++++++
 4 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index b160b8e124e0..ff668686717b 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -400,6 +400,9 @@ static inline bool btrfs_inode_in_log(struct btrfs_inode *inode, u64 generation)
  */
 static inline bool btrfs_inode_can_compress(const struct btrfs_inode *inode)
 {
+	if (IS_ENCRYPTED(&inode->vfs_inode))
+		return false;
+
 	if (inode->flags & BTRFS_INODE_NODATACOW ||
 	    inode->flags & BTRFS_INODE_NODATASUM)
 		return false;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a93b205c663b..31cd95bed301 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1923,7 +1923,7 @@ 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)) {
 		btrfs_inode_unlock(inode, ilock_flags);
 		goto buffered;
 	}
@@ -3772,7 +3772,7 @@ 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))
 		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 9c9f640be636..7c856ce965f9 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 e5c2616a486e..466dfccba094 100644
--- a/fs/btrfs/reflink.c
+++ b/fs/btrfs/reflink.c
@@ -806,6 +806,13 @@ 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.
+	 */
+	if (!fscrypt_have_same_policy(inode_in, inode_out)) {
+		return -EINVAL;
+	}
+
 	/* Don't make the dst file partly checksummed */
 	if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) !=
 	    (BTRFS_I(inode_out)->flags & BTRFS_INODE_NODATASUM)) {
-- 
2.35.1

