ext4 crypto: migrate into vfs's crypto engine

This patch removes the most parts of internal crypto codes.
And then, it modifies and adds some ext4-specific crypt codes to use the generic
facility.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/Kconfig

@@ -99,17 +99,9 @@ config EXT4_FS_SECURITY
 	  extended attributes for file security labels, say N.
 
 config EXT4_ENCRYPTION
-	tristate "Ext4 Encryption"
+	bool "Ext4 Encryption"
 	depends on EXT4_FS
-	select CRYPTO_AES
-	select CRYPTO_CBC
-	select CRYPTO_ECB
-	select CRYPTO_XTS
-	select CRYPTO_CTS
-	select CRYPTO_CTR
-	select CRYPTO_SHA256
-	select KEYS
-	select ENCRYPTED_KEYS
+	select FS_ENCRYPTION
 	help
 	  Enable encryption of ext4 files and directories.  This
 	  feature is similar to ecryptfs, but it is more memory

fs/ext4/Makefile

@@ -12,5 +12,3 @@ ext4-y	:= balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o page-io.o \
 
 ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
 ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o
-ext4-$(CONFIG_EXT4_FS_ENCRYPTION)	+= crypto_policy.o crypto.o \
-		crypto_key.o crypto_fname.o

fs/ext4/crypto_key.c

-/*
- * linux/fs/ext4/crypto_key.c
- *
- * Copyright (C) 2015, Google, Inc.
- *
- * This contains encryption key functions for ext4
- *
- * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
- */
-
-#include <crypto/skcipher.h>
-#include <keys/encrypted-type.h>
-#include <keys/user-type.h>
-#include <linux/random.h>
-#include <linux/scatterlist.h>
-#include <uapi/linux/keyctl.h>
-
-#include "ext4.h"
-#include "xattr.h"
-
-static void derive_crypt_complete(struct crypto_async_request *req, int rc)
-{
-	struct ext4_completion_result *ecr = req->data;
-
-	if (rc == -EINPROGRESS)
-		return;
-
-	ecr->res = rc;
-	complete(&ecr->completion);
-}
-
-/**
- * ext4_derive_key_aes() - Derive a key using AES-128-ECB
- * @deriving_key: Encryption key used for derivation.
- * @source_key:   Source key to which to apply derivation.
- * @derived_key:  Derived key.
- *
- * Return: Zero on success; non-zero otherwise.
- */
-static int ext4_derive_key_aes(char deriving_key[EXT4_AES_128_ECB_KEY_SIZE],
-			       char source_key[EXT4_AES_256_XTS_KEY_SIZE],
-			       char derived_key[EXT4_AES_256_XTS_KEY_SIZE])
-{
-	int res = 0;
-	struct skcipher_request *req = NULL;
-	DECLARE_EXT4_COMPLETION_RESULT(ecr);
-	struct scatterlist src_sg, dst_sg;
-	struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
-
-	if (IS_ERR(tfm)) {
-		res = PTR_ERR(tfm);
-		tfm = NULL;
-		goto out;
-	}
-	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
-	req = skcipher_request_alloc(tfm, GFP_NOFS);
-	if (!req) {
-		res = -ENOMEM;
-		goto out;
-	}
-	skcipher_request_set_callback(req,
-			CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-			derive_crypt_complete, &ecr);
-	res = crypto_skcipher_setkey(tfm, deriving_key,
-				     EXT4_AES_128_ECB_KEY_SIZE);
-	if (res < 0)
-		goto out;
-	sg_init_one(&src_sg, source_key, EXT4_AES_256_XTS_KEY_SIZE);
-	sg_init_one(&dst_sg, derived_key, EXT4_AES_256_XTS_KEY_SIZE);
-	skcipher_request_set_crypt(req, &src_sg, &dst_sg,
-				   EXT4_AES_256_XTS_KEY_SIZE, NULL);
-	res = crypto_skcipher_encrypt(req);
-	if (res == -EINPROGRESS || res == -EBUSY) {
-		wait_for_completion(&ecr.completion);
-		res = ecr.res;
-	}
-
-out:
-	skcipher_request_free(req);
-	crypto_free_skcipher(tfm);
-	return res;
-}
-
-void ext4_free_crypt_info(struct ext4_crypt_info *ci)
-{
-	if (!ci)
-		return;
-
-	if (ci->ci_keyring_key)
-		key_put(ci->ci_keyring_key);
-	crypto_free_skcipher(ci->ci_ctfm);
-	kmem_cache_free(ext4_crypt_info_cachep, ci);
-}
-
-void ext4_free_encryption_info(struct inode *inode,
-			       struct ext4_crypt_info *ci)
-{
-	struct ext4_inode_info *ei = EXT4_I(inode);
-	struct ext4_crypt_info *prev;
-
-	if (ci == NULL)
-		ci = ACCESS_ONCE(ei->i_crypt_info);
-	if (ci == NULL)
-		return;
-	prev = cmpxchg(&ei->i_crypt_info, ci, NULL);
-	if (prev != ci)
-		return;
-
-	ext4_free_crypt_info(ci);
-}
-
-int _ext4_get_encryption_info(struct inode *inode)
-{
-	struct ext4_inode_info *ei = EXT4_I(inode);
-	struct ext4_crypt_info *crypt_info;
-	char full_key_descriptor[EXT4_KEY_DESC_PREFIX_SIZE +
-				 (EXT4_KEY_DESCRIPTOR_SIZE * 2) + 1];
-	struct key *keyring_key = NULL;
-	struct ext4_encryption_key *master_key;
-	struct ext4_encryption_context ctx;
-	const struct user_key_payload *ukp;
-	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-	struct crypto_skcipher *ctfm;
-	const char *cipher_str;
-	char raw_key[EXT4_MAX_KEY_SIZE];
-	char mode;
-	int res;
-
-	if (!ext4_read_workqueue) {
-		res = ext4_init_crypto();
-		if (res)
-			return res;
-	}
-
-retry:
-	crypt_info = ACCESS_ONCE(ei->i_crypt_info);
-	if (crypt_info) {
-		if (!crypt_info->ci_keyring_key ||
-		    key_validate(crypt_info->ci_keyring_key) == 0)
-			return 0;
-		ext4_free_encryption_info(inode, crypt_info);
-		goto retry;
-	}
-
-	res = ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
-				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
-				 &ctx, sizeof(ctx));
-	if (res < 0) {
-		if (!DUMMY_ENCRYPTION_ENABLED(sbi))
-			return res;
-		ctx.contents_encryption_mode = EXT4_ENCRYPTION_MODE_AES_256_XTS;
-		ctx.filenames_encryption_mode =
-			EXT4_ENCRYPTION_MODE_AES_256_CTS;
-		ctx.flags = 0;
-	} else if (res != sizeof(ctx))
-		return -EINVAL;
-	res = 0;
-
-	crypt_info = kmem_cache_alloc(ext4_crypt_info_cachep, GFP_KERNEL);
-	if (!crypt_info)
-		return -ENOMEM;
-
-	crypt_info->ci_flags = ctx.flags;
-	crypt_info->ci_data_mode = ctx.contents_encryption_mode;
-	crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
-	crypt_info->ci_ctfm = NULL;
-	crypt_info->ci_keyring_key = NULL;
-	memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
-	       sizeof(crypt_info->ci_master_key));
-	if (S_ISREG(inode->i_mode))
-		mode = crypt_info->ci_data_mode;
-	else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
-		mode = crypt_info->ci_filename_mode;
-	else
-		BUG();
-	switch (mode) {
-	case EXT4_ENCRYPTION_MODE_AES_256_XTS:
-		cipher_str = "xts(aes)";
-		break;
-	case EXT4_ENCRYPTION_MODE_AES_256_CTS:
-		cipher_str = "cts(cbc(aes))";
-		break;
-	default:
-		printk_once(KERN_WARNING
-			    "ext4: unsupported key mode %d (ino %u)\n",
-			    mode, (unsigned) inode->i_ino);
-		res = -ENOKEY;
-		goto out;
-	}
-	if (DUMMY_ENCRYPTION_ENABLED(sbi)) {
-		memset(raw_key, 0x42, EXT4_AES_256_XTS_KEY_SIZE);
-		goto got_key;
-	}
-	memcpy(full_key_descriptor, EXT4_KEY_DESC_PREFIX,
-	       EXT4_KEY_DESC_PREFIX_SIZE);
-	sprintf(full_key_descriptor + EXT4_KEY_DESC_PREFIX_SIZE,
-		"%*phN", EXT4_KEY_DESCRIPTOR_SIZE,
-		ctx.master_key_descriptor);
-	full_key_descriptor[EXT4_KEY_DESC_PREFIX_SIZE +
-			    (2 * EXT4_KEY_DESCRIPTOR_SIZE)] = '\0';
-	keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
-	if (IS_ERR(keyring_key)) {
-		res = PTR_ERR(keyring_key);
-		keyring_key = NULL;
-		goto out;
-	}
-	crypt_info->ci_keyring_key = keyring_key;
-	if (keyring_key->type != &key_type_logon) {
-		printk_once(KERN_WARNING
-			    "ext4: key type must be logon\n");
-		res = -ENOKEY;
-		goto out;
-	}
-	down_read(&keyring_key->sem);
-	ukp = user_key_payload(keyring_key);
-	if (ukp->datalen != sizeof(struct ext4_encryption_key)) {
-		res = -EINVAL;
-		up_read(&keyring_key->sem);
-		goto out;
-	}
-	master_key = (struct ext4_encryption_key *)ukp->data;
-	BUILD_BUG_ON(EXT4_AES_128_ECB_KEY_SIZE !=
-		     EXT4_KEY_DERIVATION_NONCE_SIZE);
-	if (master_key->size != EXT4_AES_256_XTS_KEY_SIZE) {
-		printk_once(KERN_WARNING
-			    "ext4: key size incorrect: %d\n",
-			    master_key->size);
-		res = -ENOKEY;
-		up_read(&keyring_key->sem);
-		goto out;
-	}
-	res = ext4_derive_key_aes(ctx.nonce, master_key->raw,
-				  raw_key);
-	up_read(&keyring_key->sem);
-	if (res)
-		goto out;
-got_key:
-	ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
-	if (!ctfm || IS_ERR(ctfm)) {
-		res = ctfm ? PTR_ERR(ctfm) : -ENOMEM;
-		printk(KERN_DEBUG
-		       "%s: error %d (inode %u) allocating crypto tfm\n",
-		       __func__, res, (unsigned) inode->i_ino);
-		goto out;
-	}
-	crypt_info->ci_ctfm = ctfm;
-	crypto_skcipher_clear_flags(ctfm, ~0);
-	crypto_tfm_set_flags(crypto_skcipher_tfm(ctfm),
-			     CRYPTO_TFM_REQ_WEAK_KEY);
-	res = crypto_skcipher_setkey(ctfm, raw_key,
-				     ext4_encryption_key_size(mode));
-	if (res)
-		goto out;
-	memzero_explicit(raw_key, sizeof(raw_key));
-	if (cmpxchg(&ei->i_crypt_info, NULL, crypt_info) != NULL) {
-		ext4_free_crypt_info(crypt_info);
-		goto retry;
-	}
-	return 0;
-
-out:
-	if (res == -ENOKEY)
-		res = 0;
-	ext4_free_crypt_info(crypt_info);
-	memzero_explicit(raw_key, sizeof(raw_key));
-	return res;
-}
-
-int ext4_has_encryption_key(struct inode *inode)
-{
-	struct ext4_inode_info *ei = EXT4_I(inode);
-
-	return (ei->i_crypt_info != NULL);
-}

fs/ext4/crypto_policy.c

-/*
- * linux/fs/ext4/crypto_policy.c
- *
- * Copyright (C) 2015, Google, Inc.
- *
- * This contains encryption policy functions for ext4
- *
- * Written by Michael Halcrow, 2015.
- */
-
-#include <linux/random.h>
-#include <linux/string.h>
-#include <linux/types.h>
-
-#include "ext4_jbd2.h"
-#include "ext4.h"
-#include "xattr.h"
-
-static int ext4_inode_has_encryption_context(struct inode *inode)
-{
-	int res = ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
-				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, NULL, 0);
-	return (res > 0);
-}
-
-/*
- * check whether the policy is consistent with the encryption context
- * for the inode
- */
-static int ext4_is_encryption_context_consistent_with_policy(
-	struct inode *inode, const struct ext4_encryption_policy *policy)
-{
-	struct ext4_encryption_context ctx;
-	int res = ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
-				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
-				 sizeof(ctx));
-	if (res != sizeof(ctx))
-		return 0;
-	return (memcmp(ctx.master_key_descriptor, policy->master_key_descriptor,
-			EXT4_KEY_DESCRIPTOR_SIZE) == 0 &&
-		(ctx.flags ==
-		 policy->flags) &&
-		(ctx.contents_encryption_mode ==
-		 policy->contents_encryption_mode) &&
-		(ctx.filenames_encryption_mode ==
-		 policy->filenames_encryption_mode));
-}
-
-static int ext4_create_encryption_context_from_policy(
-	struct inode *inode, const struct ext4_encryption_policy *policy)
-{
-	struct ext4_encryption_context ctx;
-	handle_t *handle;
-	int res, res2;
-
-	res = ext4_convert_inline_data(inode);
-	if (res)
-		return res;
-
-	ctx.format = EXT4_ENCRYPTION_CONTEXT_FORMAT_V1;
-	memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
-	       EXT4_KEY_DESCRIPTOR_SIZE);
-	if (!ext4_valid_contents_enc_mode(policy->contents_encryption_mode)) {
-		printk(KERN_WARNING
-		       "%s: Invalid contents encryption mode %d\n", __func__,
-			policy->contents_encryption_mode);
-		return -EINVAL;
-	}
-	if (!ext4_valid_filenames_enc_mode(policy->filenames_encryption_mode)) {
-		printk(KERN_WARNING
-		       "%s: Invalid filenames encryption mode %d\n", __func__,
-			policy->filenames_encryption_mode);
-		return -EINVAL;
-	}
-	if (policy->flags & ~EXT4_POLICY_FLAGS_VALID)
-		return -EINVAL;
-	ctx.contents_encryption_mode = policy->contents_encryption_mode;
-	ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
-	ctx.flags = policy->flags;
-	BUILD_BUG_ON(sizeof(ctx.nonce) != EXT4_KEY_DERIVATION_NONCE_SIZE);
-	get_random_bytes(ctx.nonce, EXT4_KEY_DERIVATION_NONCE_SIZE);
-
-	handle = ext4_journal_start(inode, EXT4_HT_MISC,
-				    ext4_jbd2_credits_xattr(inode));
-	if (IS_ERR(handle))
-		return PTR_ERR(handle);
-	res = ext4_xattr_set(inode, EXT4_XATTR_INDEX_ENCRYPTION,
-			     EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
-			     sizeof(ctx), 0);
-	if (!res) {
-		ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
-		res = ext4_mark_inode_dirty(handle, inode);
-		if (res)
-			EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
-	}
-	res2 = ext4_journal_stop(handle);
-	if (!res)
-		res = res2;
-	return res;
-}
-
-int ext4_process_policy(const struct ext4_encryption_policy *policy,
-			struct inode *inode)
-{
-	if (policy->version != 0)
-		return -EINVAL;
-
-	if (!ext4_inode_has_encryption_context(inode)) {
-		if (!S_ISDIR(inode->i_mode))
-			return -EINVAL;
-		if (!ext4_empty_dir(inode))
-			return -ENOTEMPTY;
-		return ext4_create_encryption_context_from_policy(inode,
-								  policy);
-	}
-
-	if (ext4_is_encryption_context_consistent_with_policy(inode, policy))
-		return 0;
-
-	printk(KERN_WARNING "%s: Policy inconsistent with encryption context\n",
-	       __func__);
-	return -EINVAL;
-}
-
-int ext4_get_policy(struct inode *inode, struct ext4_encryption_policy *policy)
-{
-	struct ext4_encryption_context ctx;
-
-	int res = ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
-				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
-				 &ctx, sizeof(ctx));
-	if (res != sizeof(ctx))
-		return -ENOENT;
-	if (ctx.format != EXT4_ENCRYPTION_CONTEXT_FORMAT_V1)
-		return -EINVAL;
-	policy->version = 0;
-	policy->contents_encryption_mode = ctx.contents_encryption_mode;
-	policy->filenames_encryption_mode = ctx.filenames_encryption_mode;
-	policy->flags = ctx.flags;
-	memcpy(&policy->master_key_descriptor, ctx.master_key_descriptor,
-	       EXT4_KEY_DESCRIPTOR_SIZE);
-	return 0;
-}
-
-int ext4_is_child_context_consistent_with_parent(struct inode *parent,
-						 struct inode *child)
-{
-	struct ext4_crypt_info *parent_ci, *child_ci;
-	int res;
-
-	if ((parent == NULL) || (child == NULL)) {
-		pr_err("parent %p child %p\n", parent, child);
-		WARN_ON(1);	/* Should never happen */
-		return 0;
-	}
-	/* no restrictions if the parent directory is not encrypted */
-	if (!ext4_encrypted_inode(parent))
-		return 1;
-	/* if the child directory is not encrypted, this is always a problem */
-	if (!ext4_encrypted_inode(child))
-		return 0;
-	res = ext4_get_encryption_info(parent);
-	if (res)
-		return 0;
-	res = ext4_get_encryption_info(child);
-	if (res)
-		return 0;
-	parent_ci = EXT4_I(parent)->i_crypt_info;
-	child_ci = EXT4_I(child)->i_crypt_info;
-	if (!parent_ci && !child_ci)
-		return 1;
-	if (!parent_ci || !child_ci)
-		return 0;
-
-	return (memcmp(parent_ci->ci_master_key,
-		       child_ci->ci_master_key,
-		       EXT4_KEY_DESCRIPTOR_SIZE) == 0 &&
-		(parent_ci->ci_data_mode == child_ci->ci_data_mode) &&
-		(parent_ci->ci_filename_mode == child_ci->ci_filename_mode) &&
-		(parent_ci->ci_flags == child_ci->ci_flags));
-}
-
-/**
- * ext4_inherit_context() - Sets a child context from its parent
- * @parent: Parent inode from which the context is inherited.
- * @child:  Child inode that inherits the context from @parent.
- *
- * Return: Zero on success, non-zero otherwise
- */
-int ext4_inherit_context(struct inode *parent, struct inode *child)
-{
-	struct ext4_encryption_context ctx;
-	struct ext4_crypt_info *ci;
-	int res;
-
-	res = ext4_get_encryption_info(parent);
-	if (res < 0)
-		return res;
-	ci = EXT4_I(parent)->i_crypt_info;
-	if (ci == NULL)
-		return -ENOKEY;
-
-	ctx.format = EXT4_ENCRYPTION_CONTEXT_FORMAT_V1;
-	if (DUMMY_ENCRYPTION_ENABLED(EXT4_SB(parent->i_sb))) {
-		ctx.contents_encryption_mode = EXT4_ENCRYPTION_MODE_AES_256_XTS;
-		ctx.filenames_encryption_mode =
-			EXT4_ENCRYPTION_MODE_AES_256_CTS;
-		ctx.flags = 0;
-		memset(ctx.master_key_descriptor, 0x42,
-		       EXT4_KEY_DESCRIPTOR_SIZE);
-		res = 0;
-	} else {
-		ctx.contents_encryption_mode = ci->ci_data_mode;
-		ctx.filenames_encryption_mode = ci->ci_filename_mode;
-		ctx.flags = ci->ci_flags;
-		memcpy(ctx.master_key_descriptor, ci->ci_master_key,
-		       EXT4_KEY_DESCRIPTOR_SIZE);
-	}
-	get_random_bytes(ctx.nonce, EXT4_KEY_DERIVATION_NONCE_SIZE);
-	res = ext4_xattr_set(child, EXT4_XATTR_INDEX_ENCRYPTION,
-			     EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
-			     sizeof(ctx), 0);
-	if (!res) {
-		ext4_set_inode_flag(child, EXT4_INODE_ENCRYPT);
-		ext4_clear_inode_state(child, EXT4_STATE_MAY_INLINE_DATA);
-		res = ext4_get_encryption_info(child);
-	}
-	return res;
-}

fs/ext4/dir.c

@@ -109,10 +109,10 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
 	struct super_block *sb = inode->i_sb;
 	struct buffer_head *bh = NULL;
 	int dir_has_error = 0;
-	struct ext4_str fname_crypto_str = {.name = NULL, .len = 0};
+	struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
 
 	if (ext4_encrypted_inode(inode)) {
-		err = ext4_get_encryption_info(inode);
+		err = fscrypt_get_encryption_info(inode);
 		if (err && err != -ENOKEY)
 			return err;
 	}
@@ -139,8 +139,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
 	}
 
 	if (ext4_encrypted_inode(inode)) {
-		err = ext4_fname_crypto_alloc_buffer(inode, EXT4_NAME_LEN,
-						     &fname_crypto_str);
+		err = fscrypt_fname_alloc_buffer(inode, EXT4_NAME_LEN, &fstr);
 		if (err < 0)
 			return err;
 	}
@@ -253,16 +252,19 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
 					    get_dtype(sb, de->file_type)))
 						goto done;
 				} else {
-					int save_len = fname_crypto_str.len;
+					int save_len = fstr.len;
+					struct fscrypt_str de_name =
+							FSTR_INIT(de->name,
+								de->name_len);
 
 					/* Directory is encrypted */
-					err = ext4_fname_disk_to_usr(inode,
-						NULL, de, &fname_crypto_str);
-					fname_crypto_str.len = save_len;
+					err = fscrypt_fname_disk_to_usr(inode,
+						0, 0, &de_name, &fstr);
+					fstr.len = save_len;
 					if (err < 0)
 						goto errout;
 					if (!dir_emit(ctx,
-					    fname_crypto_str.name, err,
+					    fstr.name, err,
 					    le32_to_cpu(de->inode),
 					    get_dtype(sb, de->file_type)))
 						goto done;
@@ -281,7 +283,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
 	err = 0;
 errout:
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-	ext4_fname_crypto_free_buffer(&fname_crypto_str);
+	fscrypt_fname_free_buffer(&fstr);
 #endif
 	brelse(bh);
 	return err;
@@ -432,7 +434,7 @@ void ext4_htree_free_dir_info(struct dir_private_info *p)
 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 			     __u32 minor_hash,
 			    struct ext4_dir_entry_2 *dirent,
-			    struct ext4_str *ent_name)
+			    struct fscrypt_str *ent_name)
 {
 	struct rb_node **p, *parent = NULL;
 	struct fname *fname, *new_fn;
@@ -609,7 +611,7 @@ static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
 static int ext4_dir_open(struct inode * inode, struct file * filp)
 {
 	if (ext4_encrypted_inode(inode))
-		return ext4_get_encryption_info(inode) ? -EACCES : 0;
+		return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
 	return 0;
 }
 

fs/ext4/ext4_crypto.h

-/*
- * linux/fs/ext4/ext4_crypto.h
- *
- * Copyright (C) 2015, Google, Inc.
- *
- * This contains encryption header content for ext4
- *
- * Written by Michael Halcrow, 2015.
- */
-
-#ifndef _EXT4_CRYPTO_H
-#define _EXT4_CRYPTO_H
-
-#include <linux/fs.h>
-
-#define EXT4_KEY_DESCRIPTOR_SIZE 8
-
-/* Policy provided via an ioctl on the topmost directory */
-struct ext4_encryption_policy {
-	char version;
-	char contents_encryption_mode;
-	char filenames_encryption_mode;
-	char flags;
-	char master_key_descriptor[EXT4_KEY_DESCRIPTOR_SIZE];
-} __attribute__((__packed__));
-
-#define EXT4_ENCRYPTION_CONTEXT_FORMAT_V1 1
-#define EXT4_KEY_DERIVATION_NONCE_SIZE 16
-
-#define EXT4_POLICY_FLAGS_PAD_4		0x00
-#define EXT4_POLICY_FLAGS_PAD_8		0x01
-#define EXT4_POLICY_FLAGS_PAD_16	0x02
-#define EXT4_POLICY_FLAGS_PAD_32	0x03
-#define EXT4_POLICY_FLAGS_PAD_MASK	0x03
-#define EXT4_POLICY_FLAGS_VALID		0x03
-
-/**
- * Encryption context for inode
- *
- * Protector format:
- *  1 byte: Protector format (1 = this version)
- *  1 byte: File contents encryption mode
- *  1 byte: File names encryption mode
- *  1 byte: Reserved
- *  8 bytes: Master Key descriptor
- *  16 bytes: Encryption Key derivation nonce
- */
-struct ext4_encryption_context {
-	char format;
-	char contents_encryption_mode;
-	char filenames_encryption_mode;
-	char flags;
-	char master_key_descriptor[EXT4_KEY_DESCRIPTOR_SIZE];
-	char nonce[EXT4_KEY_DERIVATION_NONCE_SIZE];
-} __attribute__((__packed__));
-
-/* Encryption parameters */
-#define EXT4_XTS_TWEAK_SIZE 16
-#define EXT4_AES_128_ECB_KEY_SIZE 16
-#define EXT4_AES_256_GCM_KEY_SIZE 32
-#define EXT4_AES_256_CBC_KEY_SIZE 32
-#define EXT4_AES_256_CTS_KEY_SIZE 32
-#define EXT4_AES_256_XTS_KEY_SIZE 64
-#define EXT4_MAX_KEY_SIZE 64
-
-#define EXT4_KEY_DESC_PREFIX "ext4:"
-#define EXT4_KEY_DESC_PREFIX_SIZE 5
-
-/* This is passed in from userspace into the kernel keyring */
-struct ext4_encryption_key {
-        __u32 mode;
-        char raw[EXT4_MAX_KEY_SIZE];
-        __u32 size;
-} __attribute__((__packed__));
-
-struct ext4_crypt_info {
-	char		ci_data_mode;
-	char		ci_filename_mode;
-	char		ci_flags;
-	struct crypto_skcipher *ci_ctfm;
-	struct key	*ci_keyring_key;
-	char		ci_master_key[EXT4_KEY_DESCRIPTOR_SIZE];
-};
-
-#define EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL             0x00000001
-#define EXT4_WRITE_PATH_FL			      0x00000002
-
-struct ext4_crypto_ctx {
-	union {
-		struct {
-			struct page *bounce_page;       /* Ciphertext page */
-			struct page *control_page;      /* Original page  */
-		} w;
-		struct {
-			struct bio *bio;
-			struct work_struct work;
-		} r;
-		struct list_head free_list;     /* Free list */
-	};
-	char flags;                      /* Flags */
-	char mode;                       /* Encryption mode for tfm */
-};
-
-struct ext4_completion_result {
-	struct completion completion;
-	int res;
-};
-
-#define DECLARE_EXT4_COMPLETION_RESULT(ecr) \
-	struct ext4_completion_result ecr = { \
-		COMPLETION_INITIALIZER((ecr).completion), 0 }
-
-static inline int ext4_encryption_key_size(int mode)
-{
-	switch (mode) {
-	case EXT4_ENCRYPTION_MODE_AES_256_XTS:
-		return EXT4_AES_256_XTS_KEY_SIZE;
-	case EXT4_ENCRYPTION_MODE_AES_256_GCM:
-		return EXT4_AES_256_GCM_KEY_SIZE;
-	case EXT4_ENCRYPTION_MODE_AES_256_CBC:
-		return EXT4_AES_256_CBC_KEY_SIZE;
-	case EXT4_ENCRYPTION_MODE_AES_256_CTS:
-		return EXT4_AES_256_CTS_KEY_SIZE;
-	default:
-		BUG();
-	}
-	return 0;
-}
-
-#define EXT4_FNAME_NUM_SCATTER_ENTRIES	4
-#define EXT4_CRYPTO_BLOCK_SIZE		16
-#define EXT4_FNAME_CRYPTO_DIGEST_SIZE	32
-
-struct ext4_str {
-	unsigned char *name;
-	u32 len;
-};
-
-/**
- * For encrypted symlinks, the ciphertext length is stored at the beginning
- * of the string in little-endian format.
- */
-struct ext4_encrypted_symlink_data {
-	__le16 len;
-	char encrypted_path[1];
-} __attribute__((__packed__));
-
-/**
- * This function is used to calculate the disk space required to
- * store a filename of length l in encrypted symlink format.
- */
-static inline u32 encrypted_symlink_data_len(u32 l)
-{
-	if (l < EXT4_CRYPTO_BLOCK_SIZE)
-		l = EXT4_CRYPTO_BLOCK_SIZE;
-	return (l + sizeof(struct ext4_encrypted_symlink_data) - 1);
-}
-
-#endif	/* _EXT4_CRYPTO_H */

fs/ext4/file.c

@@ -303,10 +303,10 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
 	struct inode *inode = file->f_mapping->host;
 
 	if (ext4_encrypted_inode(inode)) {
-		int err = ext4_get_encryption_info(inode);
+		int err = fscrypt_get_encryption_info(inode);
 		if (err)
 			return 0;
-		if (ext4_encryption_info(inode) == NULL)
+		if (!fscrypt_has_encryption_key(inode))
 			return -ENOKEY;
 	}
 	file_accessed(file);
@@ -362,16 +362,16 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
 		}
 	}
 	if (ext4_encrypted_inode(inode)) {
-		ret = ext4_get_encryption_info(inode);
+		ret = fscrypt_get_encryption_info(inode);
 		if (ret)
 			return -EACCES;
-		if (ext4_encryption_info(inode) == NULL)
+		if (!fscrypt_has_encryption_key(inode))
 			return -ENOKEY;
 	}
 
 	dir = dget_parent(file_dentry(filp));
 	if (ext4_encrypted_inode(d_inode(dir)) &&
-	    !ext4_is_child_context_consistent_with_parent(d_inode(dir), inode)) {
+			!fscrypt_has_permitted_context(d_inode(dir), inode)) {
 		ext4_warning(inode->i_sb,
 			     "Inconsistent encryption contexts: %lu/%lu",
 			     (unsigned long) d_inode(dir)->i_ino,

fs/ext4/ialloc.c

@@ -767,10 +767,10 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 	if ((ext4_encrypted_inode(dir) ||
 	     DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb))) &&
 	    (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
-		err = ext4_get_encryption_info(dir);
+		err = fscrypt_get_encryption_info(dir);
 		if (err)
 			return ERR_PTR(err);
-		if (ext4_encryption_info(dir) == NULL)
+		if (!fscrypt_has_encryption_key(dir))
 			return ERR_PTR(-EPERM);
 		if (!handle)
 			nblocks += EXT4_DATA_TRANS_BLOCKS(dir->i_sb);
@@ -1115,7 +1115,8 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 	}
 
 	if (encrypt) {
-		err = ext4_inherit_context(dir, inode);
+		/* give pointer to avoid set_context with journal ops. */
+		err = fscrypt_inherit_context(dir, inode, &encrypt, true);
 		if (err)
 			goto fail_free_drop;
 	}

fs/ext4/inline.c

@@ -1326,7 +1326,7 @@ int htree_inlinedir_to_tree(struct file *dir_file,
 	struct ext4_iloc iloc;
 	void *dir_buf = NULL;
 	struct ext4_dir_entry_2 fake;
-	struct ext4_str tmp_str;
+	struct fscrypt_str tmp_str;
 
 	ret = ext4_get_inode_loc(inode, &iloc);
 	if (ret)
@@ -1739,20 +1739,20 @@ ext4_get_inline_entry(struct inode *inode,
 	return (struct ext4_dir_entry_2 *)(inline_pos + offset);
 }
 
-int empty_inline_dir(struct inode *dir, int *has_inline_data)
+bool empty_inline_dir(struct inode *dir, int *has_inline_data)
 {
 	int err, inline_size;
 	struct ext4_iloc iloc;
 	void *inline_pos;
 	unsigned int offset;
 	struct ext4_dir_entry_2 *de;
-	int ret = 1;
+	bool ret = true;
 
 	err = ext4_get_inode_loc(dir, &iloc);
 	if (err) {
 		EXT4_ERROR_INODE(dir, "error %d getting inode %lu block",
 				 err, dir->i_ino);
-		return 1;
+		return true;
 	}
 
 	down_read(&EXT4_I(dir)->xattr_sem);
@@ -1766,7 +1766,7 @@ int empty_inline_dir(struct inode *dir, int *has_inline_data)
 		ext4_warning(dir->i_sb,
 			     "bad inline directory (dir #%lu) - no `..'",
 			     dir->i_ino);
-		ret = 1;
+		ret = true;
 		goto out;
 	}
 
@@ -1784,11 +1784,11 @@ int empty_inline_dir(struct inode *dir, int *has_inline_data)
 				     dir->i_ino, le32_to_cpu(de->inode),
 				     le16_to_cpu(de->rec_len), de->name_len,
 				     inline_size);
-			ret = 1;
+			ret = true;
 			goto out;
 		}
 		if (le32_to_cpu(de->inode)) {
-			ret = 0;
+			ret = false;
 			goto out;
 		}
 		offset += ext4_rec_len_from_disk(de->rec_len, inline_size);

fs/ext4/inode.c

@@ -392,7 +392,7 @@ int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
 	int ret;
 
 	if (ext4_encrypted_inode(inode))
-		return ext4_encrypted_zeroout(inode, lblk, pblk, len);
+		return fscrypt_zeroout_range(inode, lblk, pblk, len);
 
 	ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
 	if (ret > 0)
@@ -1158,7 +1158,7 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
 	if (unlikely(err))
 		page_zero_new_buffers(page, from, to);
 	else if (decrypt)
-		err = ext4_decrypt(page);
+		err = fscrypt_decrypt_page(page);
 	return err;
 }
 #endif
@@ -3735,9 +3735,9 @@ static int __ext4_block_zero_page_range(handle_t *handle,
 		if (S_ISREG(inode->i_mode) &&
 		    ext4_encrypted_inode(inode)) {
 			/* We expect the key to be set. */
-			BUG_ON(!ext4_has_encryption_key(inode));
+			BUG_ON(!fscrypt_has_encryption_key(inode));
 			BUG_ON(blocksize != PAGE_SIZE);
-			WARN_ON_ONCE(ext4_decrypt(page));
+			WARN_ON_ONCE(fscrypt_decrypt_page(page));
 		}
 	}
 	if (ext4_should_journal_data(inode)) {

fs/ext4/ioctl.c

@@ -770,19 +770,13 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return ext4_ext_precache(inode);
 	case EXT4_IOC_SET_ENCRYPTION_POLICY: {
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-		struct ext4_encryption_policy policy;
-		int err = 0;
+		struct fscrypt_policy policy;
 
 		if (copy_from_user(&policy,
-				   (struct ext4_encryption_policy __user *)arg,
-				   sizeof(policy))) {
-			err = -EFAULT;
-			goto encryption_policy_out;
-		}
-
-		err = ext4_process_policy(&policy, inode);
-encryption_policy_out:
-		return err;
+				   (struct fscrypt_policy __user *)arg,
+				   sizeof(policy)))
+			return -EFAULT;
+		return fscrypt_process_policy(inode, &policy);
 #else
 		return -EOPNOTSUPP;
 #endif
@@ -825,12 +819,12 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	}
 	case EXT4_IOC_GET_ENCRYPTION_POLICY: {
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-		struct ext4_encryption_policy policy;
+		struct fscrypt_policy policy;
 		int err = 0;
 
 		if (!ext4_encrypted_inode(inode))
 			return -ENOENT;
-		err = ext4_get_policy(inode, &policy);
+		err = fscrypt_get_policy(inode, &policy);
 		if (err)
 			return err;
 		if (copy_to_user((void __user *)arg, &policy, sizeof(policy)))

fs/ext4/page-io.c

@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/backing-dev.h>
+#include <linux/fscrypto.h>
 
 #include "ext4_jbd2.h"
 #include "xattr.h"
@@ -67,7 +68,6 @@ static void ext4_finish_bio(struct bio *bio)
 		struct page *page = bvec->bv_page;
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 		struct page *data_page = NULL;
-		struct ext4_crypto_ctx *ctx = NULL;
 #endif
 		struct buffer_head *bh, *head;
 		unsigned bio_start = bvec->bv_offset;
@@ -82,8 +82,7 @@ static void ext4_finish_bio(struct bio *bio)
 		if (!page->mapping) {
 			/* The bounce data pages are unmapped. */
 			data_page = page;
-			ctx = (struct ext4_crypto_ctx *)page_private(data_page);
-			page = ctx->w.control_page;
+			fscrypt_pullback_bio_page(&page, false);
 		}
 #endif
 
@@ -113,8 +112,8 @@ static void ext4_finish_bio(struct bio *bio)
 		local_irq_restore(flags);
 		if (!under_io) {
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-			if (ctx)
-				ext4_restore_control_page(data_page);
+			if (data_page)
+				fscrypt_restore_control_page(data_page);
 #endif
 			end_page_writeback(page);
 		}
@@ -472,7 +471,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
 		gfp_t gfp_flags = GFP_NOFS;
 
 	retry_encrypt:
-		data_page = ext4_encrypt(inode, page, gfp_flags);
+		data_page = fscrypt_encrypt_page(inode, page, gfp_flags);
 		if (IS_ERR(data_page)) {
 			ret = PTR_ERR(data_page);
 			if (ret == -ENOMEM && wbc->sync_mode == WB_SYNC_ALL) {
@@ -510,7 +509,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
 	if (ret) {
 	out:
 		if (data_page)
-			ext4_restore_control_page(data_page);
+			fscrypt_restore_control_page(data_page);
 		printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
 		redirty_page_for_writepage(wbc, page);
 		do {

fs/ext4/readpage.c

@@ -46,37 +46,6 @@
 
 #include "ext4.h"
 
-/*
- * Call ext4_decrypt on every single page, reusing the encryption
- * context.
- */
-static void completion_pages(struct work_struct *work)
-{
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-	struct ext4_crypto_ctx *ctx =
-		container_of(work, struct ext4_crypto_ctx, r.work);
-	struct bio	*bio	= ctx->r.bio;
-	struct bio_vec	*bv;
-	int		i;
-
-	bio_for_each_segment_all(bv, bio, i) {
-		struct page *page = bv->bv_page;
-
-		int ret = ext4_decrypt(page);
-		if (ret) {
-			WARN_ON_ONCE(1);
-			SetPageError(page);
-		} else
-			SetPageUptodate(page);
-		unlock_page(page);
-	}
-	ext4_release_crypto_ctx(ctx);
-	bio_put(bio);
-#else
-	BUG();
-#endif
-}
-
 static inline bool ext4_bio_encrypted(struct bio *bio)
 {
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
@@ -104,14 +73,10 @@ static void mpage_end_io(struct bio *bio)
 	int i;
 
 	if (ext4_bio_encrypted(bio)) {
-		struct ext4_crypto_ctx *ctx = bio->bi_private;
-
 		if (bio->bi_error) {
-			ext4_release_crypto_ctx(ctx);
+			fscrypt_release_ctx(bio->bi_private);
 		} else {
-			INIT_WORK(&ctx->r.work, completion_pages);
-			ctx->r.bio = bio;
-			queue_work(ext4_read_workqueue, &ctx->r.work);
+			fscrypt_decrypt_bio_pages(bio->bi_private, bio);
 			return;
 		}
 	}
@@ -274,11 +239,11 @@ int ext4_mpage_readpages(struct address_space *mapping,
 			bio = NULL;
 		}
 		if (bio == NULL) {
-			struct ext4_crypto_ctx *ctx = NULL;
+			struct fscrypt_ctx *ctx = NULL;
 
 			if (ext4_encrypted_inode(inode) &&
 			    S_ISREG(inode->i_mode)) {
-				ctx = ext4_get_crypto_ctx(inode, GFP_NOFS);
+				ctx = fscrypt_get_ctx(inode, GFP_NOFS);
 				if (IS_ERR(ctx))
 					goto set_error_page;
 			}
@@ -286,7 +251,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
 				min_t(int, nr_pages, BIO_MAX_PAGES));
 			if (!bio) {
 				if (ctx)
-					ext4_release_crypto_ctx(ctx);
+					fscrypt_release_ctx(ctx);
 				goto set_error_page;
 			}
 			bio->bi_bdev = bdev;

fs/ext4/super.c

@@ -945,9 +945,6 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
 	ei->i_datasync_tid = 0;
 	atomic_set(&ei->i_unwritten, 0);
 	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-	ei->i_crypt_info = NULL;
-#endif
 	return &ei->vfs_inode;
 }
 
@@ -1026,8 +1023,7 @@ void ext4_clear_inode(struct inode *inode)
 		EXT4_I(inode)->jinode = NULL;
 	}
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-	if (EXT4_I(inode)->i_crypt_info)
-		ext4_free_encryption_info(inode, EXT4_I(inode)->i_crypt_info);
+	fscrypt_put_encryption_info(inode, NULL);
 #endif
 }
 
@@ -1094,6 +1090,90 @@ static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
 	return try_to_free_buffers(page);
 }
 
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
+{
+	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
+				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
+}
+
+static int ext4_key_prefix(struct inode *inode, u8 **key)
+{
+	*key = EXT4_SB(inode->i_sb)->key_prefix;
+	return EXT4_SB(inode->i_sb)->key_prefix_size;
+}
+
+static int ext4_prepare_context(struct inode *inode)
+{
+	return ext4_convert_inline_data(inode);
+}
+
+static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
+							void *fs_data)
+{
+	handle_t *handle;
+	int res, res2;
+
+	/* fs_data is null when internally used. */
+	if (fs_data) {
+		res  = ext4_xattr_set(inode, EXT4_XATTR_INDEX_ENCRYPTION,
+				EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx,
+				len, 0);
+		if (!res) {
+			ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
+			ext4_clear_inode_state(inode,
+					EXT4_STATE_MAY_INLINE_DATA);
+		}
+		return res;
+	}
+
+	handle = ext4_journal_start(inode, EXT4_HT_MISC,
+			ext4_jbd2_credits_xattr(inode));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	res = ext4_xattr_set(inode, EXT4_XATTR_INDEX_ENCRYPTION,
+			EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx,
+			len, 0);
+	if (!res) {
+		ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
+		res = ext4_mark_inode_dirty(handle, inode);
+		if (res)
+			EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
+	}
+	res2 = ext4_journal_stop(handle);
+	if (!res)
+		res = res2;
+	return res;
+}
+
+static int ext4_dummy_context(struct inode *inode)
+{
+	return DUMMY_ENCRYPTION_ENABLED(EXT4_SB(inode->i_sb));
+}
+
+static unsigned ext4_max_namelen(struct inode *inode)
+{
+	return S_ISLNK(inode->i_mode) ? inode->i_sb->s_blocksize :
+		EXT4_NAME_LEN;
+}
+
+static struct fscrypt_operations ext4_cryptops = {
+	.get_context		= ext4_get_context,
+	.key_prefix		= ext4_key_prefix,
+	.prepare_context	= ext4_prepare_context,
+	.set_context		= ext4_set_context,
+	.dummy_context		= ext4_dummy_context,
+	.is_encrypted		= ext4_encrypted_inode,
+	.empty_dir		= ext4_empty_dir,
+	.max_namelen		= ext4_max_namelen,
+};
+#else
+static struct fscrypt_operations ext4_cryptops = {
+	.is_encrypted		= ext4_encrypted_inode,
+};
+#endif
+
 #ifdef CONFIG_QUOTA
 static char *quotatypes[] = INITQFNAMES;
 #define QTYPE2NAME(t) (quotatypes[t])
@@ -3693,6 +3773,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_op = &ext4_sops;
 	sb->s_export_op = &ext4_export_ops;
 	sb->s_xattr = ext4_xattr_handlers;
+	sb->s_cop = &ext4_cryptops;
 #ifdef CONFIG_QUOTA
 	sb->dq_op = &ext4_quota_operations;
 	if (ext4_has_feature_quota(sb))
@@ -4003,6 +4084,11 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
 
 	kfree(orig_data);
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	memcpy(sbi->key_prefix, EXT4_KEY_DESC_PREFIX,
+				EXT4_KEY_DESC_PREFIX_SIZE);
+	sbi->key_prefix_size = EXT4_KEY_DESC_PREFIX_SIZE;
+#endif
 	return 0;
 
 cantfind_ext4:
@@ -5431,7 +5517,6 @@ static int __init ext4_init_fs(void)
 
 static void __exit ext4_exit_fs(void)
 {
-	ext4_exit_crypto();
 	ext4_destroy_lazyinit_thread();
 	unregister_as_ext2();
 	unregister_as_ext3();

fs/ext4/symlink.c

@@ -22,23 +22,22 @@
 #include "ext4.h"
 #include "xattr.h"
 
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
 static const char *ext4_encrypted_get_link(struct dentry *dentry,
 					   struct inode *inode,
 					   struct delayed_call *done)
 {
 	struct page *cpage = NULL;
 	char *caddr, *paddr = NULL;
-	struct ext4_str cstr, pstr;
-	struct ext4_encrypted_symlink_data *sd;
+	struct fscrypt_str cstr, pstr;
+	struct fscrypt_symlink_data *sd;
 	loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
 	int res;
-	u32 plen, max_size = inode->i_sb->s_blocksize;
+	u32 max_size = inode->i_sb->s_blocksize;
 
 	if (!dentry)
 		return ERR_PTR(-ECHILD);
 
-	res = ext4_get_encryption_info(inode);
+	res = fscrypt_get_encryption_info(inode);
 	if (res)
 		return ERR_PTR(res);
 
@@ -54,30 +53,27 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
 	}
 
 	/* Symlink is encrypted */
-	sd = (struct ext4_encrypted_symlink_data *)caddr;
+	sd = (struct fscrypt_symlink_data *)caddr;
 	cstr.name = sd->encrypted_path;
 	cstr.len  = le16_to_cpu(sd->len);
-	if ((cstr.len +
-	     sizeof(struct ext4_encrypted_symlink_data) - 1) >
-	    max_size) {
+	if ((cstr.len + sizeof(struct fscrypt_symlink_data) - 1) > max_size) {
 		/* Symlink data on the disk is corrupted */
 		res = -EFSCORRUPTED;
 		goto errout;
 	}
-	plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?
-		EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len;
-	paddr = kmalloc(plen + 1, GFP_NOFS);
-	if (!paddr) {
-		res = -ENOMEM;
+
+	res = fscrypt_fname_alloc_buffer(inode, cstr.len, &pstr);
+	if (res)
 		goto errout;
-	}
-	pstr.name = paddr;
-	pstr.len = plen;
-	res = _ext4_fname_disk_to_usr(inode, NULL, &cstr, &pstr);
+
+	res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
 	if (res < 0)
 		goto errout;
+
+	paddr = pstr.name;
+
 	/* Null-terminate the name */
-	if (res <= plen)
+	if (res <= pstr.len)
 		paddr[res] = '\0';
 	if (cpage)
 		put_page(cpage);
@@ -99,7 +95,6 @@ const struct inode_operations ext4_encrypted_symlink_inode_operations = {
 	.listxattr	= ext4_listxattr,
 	.removexattr	= generic_removexattr,
 };
-#endif
 
 const struct inode_operations ext4_symlink_inode_operations = {
 	.readlink	= generic_readlink,