From: Josef Bacik <[email protected]>

The RAID5/6 code will re-arrange bios and submit them through a
different mechanism.  This is problematic with inline encryption as we
have to get the bio and csum it after it's been encrypted, and the
radi5/6 bio's don't have the btrfs_bio embedded, so we have no way to
get the csums put on disk.

This isn't an unsolvable problem, but would require a bit of reworking.
Since we discourage users from using this code currently simply don't
allow encryption on RAID5/6 setups.  If there's sufficient demand in the
future we can add the support for this.

Signed-off-by: Josef Bacik <[email protected]>
Signed-off-by: Daniel Vacek <[email protected]>
---

v5: 
https://lore.kernel.org/linux-btrfs/941f02bb923edadae1aea4ae3e5aa6ba05d1215a.1706116485.git.jo...@toxicpanda.com/
 * No changes since.
---
 fs/btrfs/ioctl.c | 4 ++++
 fs/btrfs/super.c | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index a8adf99ad0a8..1bade8fea16e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -5198,6 +5198,10 @@ long btrfs_ioctl(struct file *file, unsigned int
                        return -EOPNOTSUPP;
                if (sb_rdonly(fs_info->sb))
                        return -EROFS;
+               if (btrfs_fs_incompat(fs_info, RAID56)) {
+                       btrfs_warn(fs_info, "can't enable encryption with 
RAID5/6");
+                       return -EINVAL;
+               }
                /*
                 *  If we crash before we commit, nothing encrypted could have
                 * been written so it doesn't matter whether the encrypted
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 4a2887147ead..aefcbe56e85a 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -734,6 +734,12 @@ bool btrfs_check_options(const struct btrfs_fs_info *info,
        if (btrfs_check_mountopts_zoned(info, mount_opt))
                ret = false;
 
+       if (btrfs_fs_incompat(info, RAID56) &&
+           btrfs_raw_test_opt(*mount_opt, TEST_DUMMY_ENCRYPTION)) {
+               btrfs_err(info, "cannot use test_dummy_encryption with 
RAID5/6");
+               ret = false;
+       }
+
        if (!test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state)) {
                if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE)) {
                        btrfs_warn(info,
-- 
2.51.0


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