[PATCH v7 1/6] btrfs: disable various operations on encrypted inodes

Daniel Vacek
2025-11-18T16:08:54Z

From: Omar Sandoval <osandov@osandov.com>

Initially, only normal data extents will be encrypted. This change
forbids various other bits:
- allows reflinking only if both inodes have the same encryption status
- disable inline data on encrypted inodes

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Daniel Vacek <neelx@suse.com>
---
v5 was 'Reviewed-by: Boris Burkov <boris@bur.io>' but the rebase changed
the code a bit so dropping.
https://lore.kernel.org/linux-btrfs/20240124195303.GC1789919@zen.localdomain/
---
fs/btrfs/inode.c | 4 ++++
fs/btrfs/reflink.c | 7 +++++++
2 files changed, 11 insertions(+)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f71a5f7f55b9..8e13117eca16 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -592,6 +592,10 @@ static bool can_cow_file_range_inline(struct btrfs_inode *inode,
if (size < i_size_read(&inode->vfs_inode))
return false;

+ /* Encrypted file cannot be inlined. */
+ if (IS_ENCRYPTED(&inode->vfs_inode))
+ return false;
+
return true;
}

diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c
index 775a32a7953a..3c9c570d6493 100644
--- a/fs/btrfs/reflink.c
+++ b/fs/btrfs/reflink.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0

#include <linux/blkdev.h>
+#include <linux/fscrypt.h>
#include <linux/iversion.h>
#include "ctree.h"
#include "fs.h"
@@ -789,6 +790,12 @@ static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in,
ASSERT(inode_in->vfs_inode.i_sb == inode_out->vfs_inode.i_sb);
}

+ /*
+ * Can only reflink encrypted files if both files are encrypted.
+ */
+ if (IS_ENCRYPTED(&inode_in->vfs_inode) != IS_ENCRYPTED(&inode_out->vfs_inode))
+ return -EINVAL;
+
/* Don't make the dst file partly checksummed */
if ((inode_in->flags & BTRFS_INODE_NODATASUM) !=
(inode_out->flags & BTRFS_INODE_NODATASUM)) {
--
2.51.0