This reverts commit 0642ea2409f3 ("ext4 crypto: fix to check feature status before get policy"). The commit made a clear and documented ABI change that is not backward compatible. There exists userspace code [1] that relied on the old behavior and is now broken. While we could entertain the idea of updating the userspace code to handle the ABI change, it's my understanding that in general ABI changes that break userspace are frowned upon (to put it nicely). NOTE: if we for some reason do decide to entertain the idea of allowing the ABI change and updating userspace, I'd appreciate any help on how we should make the change. Specifically the old code relied on the different return values to differentiate between "KeyState::NO_KEY" and "KeyState::NOT_SUPPORTED". I'm no expert on the ext4 encryption APIs (I just ended up here tracking down the regression [2]) so I'd need a bit of handholding from someone. [1] https://chromium.googlesource.com/chromiumos/platform2/+/refs/heads/master/cryptohome/dircrypto_util.cc#73 [2] https://crbug.com/1018265 Fixes: 0642ea2409f3 ("ext4 crypto: fix to check feature status before get policy") Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> --- Documentation/filesystems/fscrypt.rst | 3 +-- fs/ext4/ioctl.c | 2 -- 2 files changed, 1 insertion(+), 4 deletions(-) diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 8a0700af9596..4289c29d7c5a 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -562,8 +562,7 @@ FS_IOC_GET_ENCRYPTION_POLICY_EX can fail with the following errors: or this kernel is too old to support FS_IOC_GET_ENCRYPTION_POLICY_EX (try FS_IOC_GET_ENCRYPTION_POLICY instead) - ``EOPNOTSUPP``: the kernel was not configured with encryption - support for this filesystem, or the filesystem superblock has not - had encryption enabled on it + support for this filesystem - ``EOVERFLOW``: the file is encrypted and uses a recognized encryption policy version, but the policy struct does not fit into the provided buffer diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 0b7f316fd30f..13d97fb797b4 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -1181,8 +1181,6 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) #endif } case EXT4_IOC_GET_ENCRYPTION_POLICY: - if (!ext4_has_feature_encrypt(sb)) - return -EOPNOTSUPP; return fscrypt_ioctl_get_policy(filp, (void __user *)arg); case FS_IOC_GET_ENCRYPTION_POLICY_EX: -- 2.24.0.rc1.363.gb1bccd3e3d-goog