Re: [RFC PATCH v4 17/17] ceph: add fscrypt ioctls

[Luis Henriques <lhenriques@suse.de>]

Jeff Layton <jlayton@kernel.org> writes:

> Most of the ioctls, we gate on the MDS feature support. The exception is
> the key removal and status functions that we still want to work if the
> MDS's were to (inexplicably) lose the feature.
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  fs/ceph/ioctl.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 61 insertions(+)
>
> diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
> index 6e061bf62ad4..832909f3eb1b 100644
> --- a/fs/ceph/ioctl.c
> +++ b/fs/ceph/ioctl.c
> @@ -6,6 +6,7 @@
>  #include "mds_client.h"
>  #include "ioctl.h"
>  #include <linux/ceph/striper.h>
> +#include <linux/fscrypt.h>
>  
>  /*
>   * ioctls
> @@ -268,8 +269,29 @@ static long ceph_ioctl_syncio(struct file *file)
>  	return 0;
>  }
>  
> +static int vet_mds_for_fscrypt(struct file *file)
> +{
> +	int i, ret = -EOPNOTSUPP;
> +	struct ceph_mds_client	*mdsc = ceph_sb_to_mdsc(file_inode(file)->i_sb);
> +
> +	mutex_lock(&mdsc->mutex);
> +	for (i = 0; i < mdsc->max_sessions; i++) {
> +		struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
> +
> +		if (!s)
> +			continue;
> +		if (test_bit(CEPHFS_FEATURE_ALTERNATE_NAME, &s->s_features))
> +			ret = 0;

And another one, I believe...?  We need this here:

		ceph_put_mds_session(s);

Also, isn't this logic broken?  Shouldn't we walk through all the sessions
and return 0 only if they all have that feature bit set?

Cheers,
-- 
Luis

> +		break;
> +	}
> +	mutex_unlock(&mdsc->mutex);
> +	return ret;
> +}
> +
>  long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>  {
> +	int ret;
> +
>  	dout("ioctl file %p cmd %u arg %lu\n", file, cmd, arg);
>  	switch (cmd) {
>  	case CEPH_IOC_GET_LAYOUT:
> @@ -289,6 +311,45 @@ long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>  
>  	case CEPH_IOC_SYNCIO:
>  		return ceph_ioctl_syncio(file);
> +
> +	case FS_IOC_SET_ENCRYPTION_POLICY:
> +		ret = vet_mds_for_fscrypt(file);
> +		if (ret)
> +			return ret;
> +		return fscrypt_ioctl_set_policy(file, (const void __user *)arg);
> +
> +	case FS_IOC_GET_ENCRYPTION_POLICY:
> +		ret = vet_mds_for_fscrypt(file);
> +		if (ret)
> +			return ret;
> +		return fscrypt_ioctl_get_policy(file, (void __user *)arg);
> +
> +	case FS_IOC_GET_ENCRYPTION_POLICY_EX:
> +		ret = vet_mds_for_fscrypt(file);
> +		if (ret)
> +			return ret;
> +		return fscrypt_ioctl_get_policy_ex(file, (void __user *)arg);
> +
> +	case FS_IOC_ADD_ENCRYPTION_KEY:
> +		ret = vet_mds_for_fscrypt(file);
> +		if (ret)
> +			return ret;
> +		return fscrypt_ioctl_add_key(file, (void __user *)arg);
> +
> +	case FS_IOC_REMOVE_ENCRYPTION_KEY:
> +		return fscrypt_ioctl_remove_key(file, (void __user *)arg);
> +
> +	case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
> +		return fscrypt_ioctl_remove_key_all_users(file, (void __user *)arg);
> +
> +	case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
> +		return fscrypt_ioctl_get_key_status(file, (void __user *)arg);
> +
> +	case FS_IOC_GET_ENCRYPTION_NONCE:
> +		ret = vet_mds_for_fscrypt(file);
> +		if (ret)
> +			return ret;
> +		return fscrypt_ioctl_get_nonce(file, (void __user *)arg);
>  	}
>  
>  	return -ENOTTY;
> -- 
>
> 2.29.2
>