linux-kernel - [PATCH v6 1/8] btrfs: disable various operations on encrypted inodes

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Message-ID: <20251112193611.2536093-2-neelx@suse.com>
Date: Wed, 12 Nov 2025 20:36:01 +0100
From: Daniel Vacek <neelx@...e.com>
To: Chris Mason <clm@...com>,
	Josef Bacik <josef@...icpanda.com>,
	David Sterba <dsterba@...e.com>
Cc: Daniel Vacek <neelx@...e.com>,
	linux-btrfs@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Omar Sandoval <osandov@...ndov.com>,
	Sweet Tea Dorminy <sweettea-kernel@...miny.me>
Subject: [PATCH v6 1/8] btrfs: disable various operations on encrypted inodes

From: Omar Sandoval <osandov@...ndov.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@...ndov.com>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@...miny.me>
Signed-off-by: Josef Bacik <josef@...icpanda.com>
Signed-off-by: Daniel Vacek <neelx@...e.com>
---
v5 was 'Reviewed-by: Boris Burkov <boris@....io>' [1] but the rebase
changed the code a bit so dropping.

[1] 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 8737914e8552..b810e831fc23 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