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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,
        linux-kernel@vger.kernel.org, osandov@osandov.com,
        kernel-team@fb.com
Cc:     Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Subject: [PATCH RFC v2 05/16] btrfs: disable various operations on encrypted inodes
Date:   Sat, 23 Jul 2022 20:53:50 -0400
Message-Id: <58760cc4416ca2e3903c962cc02b9bc4a251a0e9.1658623319.git.sweettea-kernel@dorminy.me>
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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: Omar Sandoval <osandov@osandov.com>
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 d199275adfa4..1fa0fe9f122f 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1896,7 +1896,7 @@ 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;
 	}
@@ -3743,7 +3743,7 @@ 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 12381c87177e..2faa0ddfedf9 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.
+	 */
+	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