f2fs: catch up to v4.14-rc1

This is cherry-picked from upstrea-f2fs-stable-linux-4.4.y.

Changes include:

commit c7fd9e2b4a6876 ("f2fs: hurry up to issue discard after io interruption")
commit 603dde39653d6d ("f2fs: fix to show correct discard_granularity in sysfs")
...
commit 565f0225f95f15 ("f2fs: factor out discard command info into discard_cmd_control")
commit c4cc29d19eaf01 ("f2fs: remove batched discard in f2fs_trim_fs")

Change-Id: Icd8a85ac0c19a8aa25cd2591a12b4e9b85bdf1c5
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>

7 files changed, 714 insertions, 435 deletions

diff --git a/fs/crypto/Makefile b/fs/crypto/Makefile
index f17684c48739..9f6607f17b53 100644
--- a/fs/crypto/Makefile
+++ b/fs/crypto/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_FS_ENCRYPTION)	+= fscrypto.o
 
 fscrypto-y := crypto.o fname.o policy.o keyinfo.o
+fscrypto-$(CONFIG_BLOCK) += bio.o
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
new file mode 100644
index 000000000000..a91ed46fe503
--- /dev/null
+++ b/fs/crypto/bio.c
@@ -0,0 +1,143 @@
+/*
+ * This contains encryption functions for per-file encryption.
+ *
+ * Copyright (C) 2015, Google, Inc.
+ * Copyright (C) 2015, Motorola Mobility
+ *
+ * Written by Michael Halcrow, 2014.
+ *
+ * Filename encryption additions
+ *	Uday Savagaonkar, 2014
+ * Encryption policy handling additions
+ *	Ildar Muslukhov, 2014
+ * Add fscrypt_pullback_bio_page()
+ *	Jaegeuk Kim, 2015.
+ *
+ * This has not yet undergone a rigorous security audit.
+ *
+ * The usage of AES-XTS should conform to recommendations in NIST
+ * Special Publication 800-38E and IEEE P1619/D16.
+ */
+
+#include <linux/pagemap.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/namei.h>
+#include "fscrypt_private.h"
+
+/*
+ * Call fscrypt_decrypt_page on every single page, reusing the encryption
+ * context.
+ */
+static void completion_pages(struct work_struct *work)
+{
+	struct fscrypt_ctx *ctx =
+		container_of(work, struct fscrypt_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 = fscrypt_decrypt_page(page->mapping->host, page,
+				PAGE_SIZE, 0, page->index);
+
+		if (ret) {
+			WARN_ON_ONCE(1);
+			SetPageError(page);
+		} else {
+			SetPageUptodate(page);
+		}
+		unlock_page(page);
+	}
+	fscrypt_release_ctx(ctx);
+	bio_put(bio);
+}
+
+void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
+{
+	INIT_WORK(&ctx->r.work, completion_pages);
+	ctx->r.bio = bio;
+	queue_work(fscrypt_read_workqueue, &ctx->r.work);
+}
+EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
+
+void fscrypt_pullback_bio_page(struct page **page, bool restore)
+{
+	struct fscrypt_ctx *ctx;
+	struct page *bounce_page;
+
+	/* The bounce data pages are unmapped. */
+	if ((*page)->mapping)
+		return;
+
+	/* The bounce data page is unmapped. */
+	bounce_page = *page;
+	ctx = (struct fscrypt_ctx *)page_private(bounce_page);
+
+	/* restore control page */
+	*page = ctx->w.control_page;
+
+	if (restore)
+		fscrypt_restore_control_page(bounce_page);
+}
+EXPORT_SYMBOL(fscrypt_pullback_bio_page);
+
+int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
+				sector_t pblk, unsigned int len)
+{
+	struct fscrypt_ctx *ctx;
+	struct page *ciphertext_page = NULL;
+	struct bio *bio;
+	int ret, err = 0;
+
+	BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
+
+	ctx = fscrypt_get_ctx(inode, GFP_NOFS);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
+	if (IS_ERR(ciphertext_page)) {
+		err = PTR_ERR(ciphertext_page);
+		goto errout;
+	}
+
+	while (len--) {
+		err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
+					     ZERO_PAGE(0), ciphertext_page,
+					     PAGE_SIZE, 0, GFP_NOFS);
+		if (err)
+			goto errout;
+
+		bio = bio_alloc(GFP_NOWAIT, 1);
+		if (!bio) {
+			err = -ENOMEM;
+			goto errout;
+		}
+		bio->bi_bdev = inode->i_sb->s_bdev;
+		bio->bi_iter.bi_sector =
+			pblk << (inode->i_sb->s_blocksize_bits - 9);
+		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+		ret = bio_add_page(bio, ciphertext_page,
+					inode->i_sb->s_blocksize, 0);
+		if (ret != inode->i_sb->s_blocksize) {
+			/* should never happen! */
+			WARN_ON(1);
+			bio_put(bio);
+			err = -EIO;
+			goto errout;
+		}
+		err = submit_bio_wait(0, bio);
+		bio_put(bio);
+		if (err)
+			goto errout;
+		lblk++;
+		pblk++;
+	}
+	err = 0;
+errout:
+	fscrypt_release_ctx(ctx);
+	return err;
+}
+EXPORT_SYMBOL(fscrypt_zeroout_range);
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 2d40ab9edc9f..c7835df7e7b8 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -24,10 +24,10 @@
 #include <linux/module.h>
 #include <linux/scatterlist.h>
 #include <linux/ratelimit.h>
-#include <linux/bio.h>
 #include <linux/dcache.h>
 #include <linux/namei.h>
-#include <linux/fscrypto.h>
+#include <crypto/aes.h>
+#include "fscrypt_private.h"
 
 static unsigned int num_prealloc_crypto_pages = 32;
 static unsigned int num_prealloc_crypto_ctxs = 128;
@@ -44,7 +44,7 @@ static mempool_t *fscrypt_bounce_page_pool = NULL;
 static LIST_HEAD(fscrypt_free_ctxs);
 static DEFINE_SPINLOCK(fscrypt_ctx_lock);
 
-static struct workqueue_struct *fscrypt_read_workqueue;
+struct workqueue_struct *fscrypt_read_workqueue;
 static DEFINE_MUTEX(fscrypt_init_mutex);
 
 static struct kmem_cache *fscrypt_ctx_cachep;
@@ -63,7 +63,7 @@ void fscrypt_release_ctx(struct fscrypt_ctx *ctx)
 {
 	unsigned long flags;
 
-	if (ctx->flags & FS_WRITE_PATH_FL && ctx->w.bounce_page) {
+	if (ctx->flags & FS_CTX_HAS_BOUNCE_BUFFER_FL && ctx->w.bounce_page) {
 		mempool_free(ctx->w.bounce_page, fscrypt_bounce_page_pool);
 		ctx->w.bounce_page = NULL;
 	}
@@ -88,7 +88,7 @@ EXPORT_SYMBOL(fscrypt_release_ctx);
  * Return: An allocated and initialized encryption context on success; error
  * value or NULL otherwise.
  */
-struct fscrypt_ctx *fscrypt_get_ctx(struct inode *inode, gfp_t gfp_flags)
+struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode, gfp_t gfp_flags)
 {
 	struct fscrypt_ctx *ctx = NULL;
 	struct fscrypt_info *ci = inode->i_crypt_info;
@@ -121,7 +121,7 @@ struct fscrypt_ctx *fscrypt_get_ctx(struct inode *inode, gfp_t gfp_flags)
 	} else {
 		ctx->flags &= ~FS_CTX_REQUIRES_FREE_ENCRYPT_FL;
 	}
-	ctx->flags &= ~FS_WRITE_PATH_FL;
+	ctx->flags &= ~FS_CTX_HAS_BOUNCE_BUFFER_FL;
 	return ctx;
 }
 EXPORT_SYMBOL(fscrypt_get_ctx);
@@ -141,20 +141,15 @@ static void page_crypt_complete(struct crypto_async_request *req, int res)
 	complete(&ecr->completion);
 }
 
-typedef enum {
-	FS_DECRYPT = 0,
-	FS_ENCRYPT,
-} fscrypt_direction_t;
-
-static int do_page_crypto(struct inode *inode,
-			fscrypt_direction_t rw, pgoff_t index,
-			struct page *src_page, struct page *dest_page,
-			gfp_t gfp_flags)
+int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw,
+			   u64 lblk_num, struct page *src_page,
+			   struct page *dest_page, unsigned int len,
+			   unsigned int offs, gfp_t gfp_flags)
 {
 	struct {
 		__le64 index;
-		u8 padding[FS_XTS_TWEAK_SIZE - sizeof(__le64)];
-	} xts_tweak;
+		u8 padding[FS_IV_SIZE - sizeof(__le64)];
+	} iv;
 	struct skcipher_request *req = NULL;
 	DECLARE_FS_COMPLETION_RESULT(ecr);
 	struct scatterlist dst, src;
@@ -162,6 +157,18 @@ static int do_page_crypto(struct inode *inode,
 	struct crypto_skcipher *tfm = ci->ci_ctfm;
 	int res = 0;
 
+	BUG_ON(len == 0);
+
+	BUILD_BUG_ON(sizeof(iv) != FS_IV_SIZE);
+	BUILD_BUG_ON(AES_BLOCK_SIZE != FS_IV_SIZE);
+	iv.index = cpu_to_le64(lblk_num);
+	memset(iv.padding, 0, sizeof(iv.padding));
+
+	if (ci->ci_essiv_tfm != NULL) {
+		crypto_cipher_encrypt_one(ci->ci_essiv_tfm, (u8 *)&iv,
+					  (u8 *)&iv);
+	}
+
 	req = skcipher_request_alloc(tfm, gfp_flags);
 	if (!req) {
 		printk_ratelimited(KERN_ERR
@@ -174,15 +181,11 @@ static int do_page_crypto(struct inode *inode,
 		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
 		page_crypt_complete, &ecr);
 
-	BUILD_BUG_ON(sizeof(xts_tweak) != FS_XTS_TWEAK_SIZE);
-	xts_tweak.index = cpu_to_le64(index);
-	memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding));
-
 	sg_init_table(&dst, 1);
-	sg_set_page(&dst, dest_page, PAGE_SIZE, 0);
+	sg_set_page(&dst, dest_page, len, offs);
 	sg_init_table(&src, 1);
-	sg_set_page(&src, src_page, PAGE_SIZE, 0);
-	skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE, &xts_tweak);
+	sg_set_page(&src, src_page, len, offs);
+	skcipher_request_set_crypt(req, &src, &dst, len, &iv);
 	if (rw == FS_DECRYPT)
 		res = crypto_skcipher_decrypt(req);
 	else
@@ -202,53 +205,86 @@ static int do_page_crypto(struct inode *inode,
 	return 0;
 }
 
-static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
+struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
+				       gfp_t gfp_flags)
 {
 	ctx->w.bounce_page = mempool_alloc(fscrypt_bounce_page_pool, gfp_flags);
 	if (ctx->w.bounce_page == NULL)
 		return ERR_PTR(-ENOMEM);
-	ctx->flags |= FS_WRITE_PATH_FL;
+	ctx->flags |= FS_CTX_HAS_BOUNCE_BUFFER_FL;
 	return ctx->w.bounce_page;
 }
 
 /**
  * fscypt_encrypt_page() - Encrypts a page
- * @inode:          The inode for which the encryption should take place
- * @plaintext_page: The page to encrypt. Must be locked.
- * @gfp_flags:      The gfp flag for memory allocation
+ * @inode:     The inode for which the encryption should take place
+ * @page:      The page to encrypt. Must be locked for bounce-page
+ *             encryption.
+ * @len:       Length of data to encrypt in @page and encrypted
+ *             data in returned page.
+ * @offs:      Offset of data within @page and returned
+ *             page holding encrypted data.
+ * @lblk_num:  Logical block number. This must be unique for multiple
+ *             calls with same inode, except when overwriting
+ *             previously written data.
+ * @gfp_flags: The gfp flag for memory allocation
  *
- * Allocates a ciphertext page and encrypts plaintext_page into it using the ctx
- * encryption context.
+ * Encrypts @page using the ctx encryption context. Performs encryption
+ * either in-place or into a newly allocated bounce page.
+ * Called on the page write path.
  *
- * Called on the page write path.  The caller must call
+ * Bounce page allocation is the default.
+ * In this case, the contents of @page are encrypted and stored in an
+ * allocated bounce page. @page has to be locked and the caller must call
  * fscrypt_restore_control_page() on the returned ciphertext page to
  * release the bounce buffer and the encryption context.
  *
- * Return: An allocated page with the encrypted content on success. Else, an
+ * In-place encryption is used by setting the FS_CFLG_OWN_PAGES flag in
+ * fscrypt_operations. Here, the input-page is returned with its content
+ * encrypted.
+ *
+ * Return: A page with the encrypted content on success. Else, an
  * error value or NULL.
  */
-struct page *fscrypt_encrypt_page(struct inode *inode,
-				struct page *plaintext_page, gfp_t gfp_flags)
+struct page *fscrypt_encrypt_page(const struct inode *inode,
+				struct page *page,
+				unsigned int len,
+				unsigned int offs,
+				u64 lblk_num, gfp_t gfp_flags)
+
 {
 	struct fscrypt_ctx *ctx;
-	struct page *ciphertext_page = NULL;
+	struct page *ciphertext_page = page;
 	int err;
 
-	BUG_ON(!PageLocked(plaintext_page));
+	BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0);
+
+	if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) {
+		/* with inplace-encryption we just encrypt the page */
+		err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page,
+					     ciphertext_page, len, offs,
+					     gfp_flags);
+		if (err)
+			return ERR_PTR(err);
+
+		return ciphertext_page;
+	}
+
+	BUG_ON(!PageLocked(page));
 
 	ctx = fscrypt_get_ctx(inode, gfp_flags);
 	if (IS_ERR(ctx))
 		return (struct page *)ctx;
 
 	/* The encryption operation will require a bounce page. */
-	ciphertext_page = alloc_bounce_page(ctx, gfp_flags);
+	ciphertext_page = fscrypt_alloc_bounce_page(ctx, gfp_flags);
 	if (IS_ERR(ciphertext_page))
 		goto errout;
 
-	ctx->w.control_page = plaintext_page;
-	err = do_page_crypto(inode, FS_ENCRYPT, plaintext_page->index,
-					plaintext_page, ciphertext_page,
-					gfp_flags);
+	ctx->w.control_page = page;
+	err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num,
+				     page, ciphertext_page, len, offs,
+				     gfp_flags);
 	if (err) {
 		ciphertext_page = ERR_PTR(err);
 		goto errout;
@@ -265,8 +301,13 @@ errout:
 EXPORT_SYMBOL(fscrypt_encrypt_page);
 
 /**
- * f2crypt_decrypt_page() - Decrypts a page in-place
- * @page: The page to decrypt. Must be locked.
+ * fscrypt_decrypt_page() - Decrypts a page in-place
+ * @inode:     The corresponding inode for the page to decrypt.
+ * @page:      The page to decrypt. Must be locked in case
+ *             it is a writeback page (FS_CFLG_OWN_PAGES unset).
+ * @len:       Number of bytes in @page to be decrypted.
+ * @offs:      Start of data in @page.
+ * @lblk_num:  Logical block number.
  *
  * Decrypts page in-place using the ctx encryption context.
  *
@@ -274,75 +315,17 @@ EXPORT_SYMBOL(fscrypt_encrypt_page);
  *
  * Return: Zero on success, non-zero otherwise.
  */
-int fscrypt_decrypt_page(struct page *page)
+int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
+			unsigned int len, unsigned int offs, u64 lblk_num)
 {
-	BUG_ON(!PageLocked(page));
+	if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES))
+		BUG_ON(!PageLocked(page));
 
-	return do_page_crypto(page->mapping->host,
-			FS_DECRYPT, page->index, page, page, GFP_NOFS);
+	return fscrypt_do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page,
+				      len, offs, GFP_NOFS);
 }
 EXPORT_SYMBOL(fscrypt_decrypt_page);
 
-int fscrypt_zeroout_range(struct inode *inode, pgoff_t lblk,
-				sector_t pblk, unsigned int len)
-{
-	struct fscrypt_ctx *ctx;
-	struct page *ciphertext_page = NULL;
-	struct bio *bio;
-	int ret, err = 0;
-
-	BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
-
-	ctx = fscrypt_get_ctx(inode, GFP_NOFS);
-	if (IS_ERR(ctx))
-		return PTR_ERR(ctx);
-
-	ciphertext_page = alloc_bounce_page(ctx, GFP_NOWAIT);
-	if (IS_ERR(ciphertext_page)) {
-		err = PTR_ERR(ciphertext_page);
-		goto errout;
-	}
-
-	while (len--) {
-		err = do_page_crypto(inode, FS_ENCRYPT, lblk,
-					ZERO_PAGE(0), ciphertext_page,
-					GFP_NOFS);
-		if (err)
-			goto errout;
-
-		bio = bio_alloc(GFP_NOWAIT, 1);
-		if (!bio) {
-			err = -ENOMEM;
-			goto errout;
-		}
-		bio->bi_bdev = inode->i_sb->s_bdev;
-		bio->bi_iter.bi_sector =
-			pblk << (inode->i_sb->s_blocksize_bits - 9);
-		ret = bio_add_page(bio, ciphertext_page,
-					inode->i_sb->s_blocksize, 0);
-		if (ret != inode->i_sb->s_blocksize) {
-			/* should never happen! */
-			WARN_ON(1);
-			bio_put(bio);
-			err = -EIO;
-			goto errout;
-		}
-		err = submit_bio_wait(WRITE, bio);
-		if ((err == 0) && bio->bi_error)
-			err = -EIO;
-		bio_put(bio);
-		if (err)
-			goto errout;
-		lblk++;
-		pblk++;
-	}
-	err = 0;
-errout:
-	fscrypt_release_ctx(ctx);
-	return err;
-}
-EXPORT_SYMBOL(fscrypt_zeroout_range);
-
 /*
  * Validate dentries for encrypted directories to make sure we aren't
  * potentially caching stale data after a key has been added or
@@ -351,7 +334,6 @@ EXPORT_SYMBOL(fscrypt_zeroout_range);
 static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 {
 	struct dentry *dir;
-	struct fscrypt_info *ci;
 	int dir_has_key, cached_with_key;
 
 	if (flags & LOOKUP_RCU)
@@ -363,18 +345,11 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 		return 0;
 	}
 
-	ci = d_inode(dir)->i_crypt_info;
-	if (ci && ci->ci_keyring_key &&
-	    (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
-					  (1 << KEY_FLAG_REVOKED) |
-					  (1 << KEY_FLAG_DEAD))))
-		ci = NULL;
-
 	/* this should eventually be an flag in d_flags */
 	spin_lock(&dentry->d_lock);
 	cached_with_key = dentry->d_flags & DCACHE_ENCRYPTED_WITH_KEY;
 	spin_unlock(&dentry->d_lock);
-	dir_has_key = (ci != NULL);
+	dir_has_key = (d_inode(dir)->i_crypt_info != NULL);
 	dput(dir);
 
 	/*
@@ -399,63 +374,6 @@ const struct dentry_operations fscrypt_d_ops = {
 };
 EXPORT_SYMBOL(fscrypt_d_ops);
 
-/*
- * Call fscrypt_decrypt_page on every single page, reusing the encryption
- * context.
- */
-static void completion_pages(struct work_struct *work)
-{
-	struct fscrypt_ctx *ctx =
-		container_of(work, struct fscrypt_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 = fscrypt_decrypt_page(page);
-
-		if (ret) {
-			WARN_ON_ONCE(1);
-			SetPageError(page);
-		} else {
-			SetPageUptodate(page);
-		}
-		unlock_page(page);
-	}
-	fscrypt_release_ctx(ctx);
-	bio_put(bio);
-}
-
-void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
-{
-	INIT_WORK(&ctx->r.work, completion_pages);
-	ctx->r.bio = bio;
-	queue_work(fscrypt_read_workqueue, &ctx->r.work);
-}
-EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
-
-void fscrypt_pullback_bio_page(struct page **page, bool restore)
-{
-	struct fscrypt_ctx *ctx;
-	struct page *bounce_page;
-
-	/* The bounce data pages are unmapped. */
-	if ((*page)->mapping)
-		return;
-
-	/* The bounce data page is unmapped. */
-	bounce_page = *page;
-	ctx = (struct fscrypt_ctx *)page_private(bounce_page);
-
-	/* restore control page */
-	*page = ctx->w.control_page;
-
-	if (restore)
-		fscrypt_restore_control_page(bounce_page);
-}
-EXPORT_SYMBOL(fscrypt_pullback_bio_page);
-
 void fscrypt_restore_control_page(struct page *page)
 {
 	struct fscrypt_ctx *ctx;
@@ -481,17 +399,22 @@ static void fscrypt_destroy(void)
 
 /**
  * fscrypt_initialize() - allocate major buffers for fs encryption.
+ * @cop_flags:  fscrypt operations flags
  *
  * We only call this when we start accessing encrypted files, since it
  * results in memory getting allocated that wouldn't otherwise be used.
  *
  * Return: Zero on success, non-zero otherwise.
  */
-int fscrypt_initialize(void)
+int fscrypt_initialize(unsigned int cop_flags)
 {
 	int i, res = -ENOMEM;
 
-	if (fscrypt_bounce_page_pool)
+	/*
+	 * No need to allocate a bounce page pool if there already is one or
+	 * this FS won't use it.
+	 */
+	if (cop_flags & FS_CFLG_OWN_PAGES || fscrypt_bounce_page_pool)
 		return 0;
 
 	mutex_lock(&fscrypt_init_mutex);
@@ -520,7 +443,6 @@ fail:
 	mutex_unlock(&fscrypt_init_mutex);
 	return res;
 }
-EXPORT_SYMBOL(fscrypt_initialize);
 
 /**
  * fscrypt_init() - Set up for fs encryption.
@@ -562,6 +484,8 @@ static void __exit fscrypt_exit(void)
 		destroy_workqueue(fscrypt_read_workqueue);
 	kmem_cache_destroy(fscrypt_ctx_cachep);
 	kmem_cache_destroy(fscrypt_info_cachep);
+
+	fscrypt_essiv_cleanup();
 }
 module_exit(fscrypt_exit);
 
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 9b774f4b50c8..ad9f814fdead 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -12,7 +12,7 @@
 
 #include <linux/scatterlist.h>
 #include <linux/ratelimit.h>
-#include <linux/fscrypto.h>
+#include "fscrypt_private.h"
 
 /**
  * fname_crypt_complete() - completion callback for filename crypto
@@ -159,6 +159,8 @@ static int fname_decrypt(struct inode *inode,
 static const char *lookup_table =
 	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
 
+#define BASE64_CHARS(nbytes)	DIV_ROUND_UP((nbytes) * 4, 3)
+
 /**
  * digest_encode() -
  *
@@ -209,7 +211,7 @@ static int digest_decode(const char *src, int len, char *dst)
 	return cp - dst;
 }
 
-u32 fscrypt_fname_encrypted_size(struct inode *inode, u32 ilen)
+u32 fscrypt_fname_encrypted_size(const struct inode *inode, u32 ilen)
 {
 	int padding = 32;
 	struct fscrypt_info *ci = inode->i_crypt_info;
@@ -227,14 +229,17 @@ EXPORT_SYMBOL(fscrypt_fname_encrypted_size);
  * Allocates an output buffer that is sufficient for the crypto operation
  * specified by the context and the direction.
  */
-int fscrypt_fname_alloc_buffer(struct inode *inode,
+int fscrypt_fname_alloc_buffer(const struct inode *inode,
 				u32 ilen, struct fscrypt_str *crypto_str)
 {
-	unsigned int olen = fscrypt_fname_encrypted_size(inode, ilen);
+	u32 olen = fscrypt_fname_encrypted_size(inode, ilen);
+	const u32 max_encoded_len =
+		max_t(u32, BASE64_CHARS(FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE),
+		      1 + BASE64_CHARS(sizeof(struct fscrypt_digested_name)));
 
 	crypto_str->len = olen;
-	if (olen < FS_FNAME_CRYPTO_DIGEST_SIZE * 2)
-		olen = FS_FNAME_CRYPTO_DIGEST_SIZE * 2;
+	olen = max(olen, max_encoded_len);
+
 	/*
 	 * Allocated buffer can hold one more character to null-terminate the
 	 * string
@@ -266,6 +271,10 @@ EXPORT_SYMBOL(fscrypt_fname_free_buffer);
  *
  * The caller must have allocated sufficient memory for the @oname string.
  *
+ * If the key is available, we'll decrypt the disk name; otherwise, we'll encode
+ * it for presentation.  Short names are directly base64-encoded, while long
+ * names are encoded in fscrypt_digested_name format.
+ *
  * Return: 0 on success, -errno on failure
  */
 int fscrypt_fname_disk_to_usr(struct inode *inode,
@@ -274,7 +283,7 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
 			struct fscrypt_str *oname)
 {
 	const struct qstr qname = FSTR_TO_QSTR(iname);
-	char buf[24];
+	struct fscrypt_digested_name digested_name;
 
 	if (fscrypt_is_dot_dotdot(&qname)) {
 		oname->name[0] = '.';
@@ -289,20 +298,24 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
 	if (inode->i_crypt_info)
 		return fname_decrypt(inode, iname, oname);
 
-	if (iname->len <= FS_FNAME_CRYPTO_DIGEST_SIZE) {
+	if (iname->len <= FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE) {
 		oname->len = digest_encode(iname->name, iname->len,
 					   oname->name);
 		return 0;
 	}
 	if (hash) {
-		memcpy(buf, &hash, 4);
-		memcpy(buf + 4, &minor_hash, 4);
+		digested_name.hash = hash;
+		digested_name.minor_hash = minor_hash;
 	} else {
-		memset(buf, 0, 8);
+		digested_name.hash = 0;
+		digested_name.minor_hash = 0;
 	}
-	memcpy(buf + 8, iname->name + iname->len - 16, 16);
+	memcpy(digested_name.digest,
+	       FSCRYPT_FNAME_DIGEST(iname->name, iname->len),
+	       FSCRYPT_FNAME_DIGEST_SIZE);
 	oname->name[0] = '_';
-	oname->len = 1 + digest_encode(buf, 24, oname->name + 1);
+	oname->len = 1 + digest_encode((const char *)&digested_name,
+				       sizeof(digested_name), oname->name + 1);
 	return 0;
 }
 EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
@@ -332,14 +345,39 @@ int fscrypt_fname_usr_to_disk(struct inode *inode,
 	 * in a directory. Consequently, a user space name cannot be mapped to
 	 * a disk-space name
 	 */
-	return -EACCES;
+	return -ENOKEY;
 }
 EXPORT_SYMBOL(fscrypt_fname_usr_to_disk);
 
+/**
+ * fscrypt_setup_filename() - prepare to search a possibly encrypted directory
+ * @dir: the directory that will be searched
+ * @iname: the user-provided filename being searched for
+ * @lookup: 1 if we're allowed to proceed without the key because it's
+ *	->lookup() or we're finding the dir_entry for deletion; 0 if we cannot
+ *	proceed without the key because we're going to create the dir_entry.
+ * @fname: the filename information to be filled in
+ *
+ * Given a user-provided filename @iname, this function sets @fname->disk_name
+ * to the name that would be stored in the on-disk directory entry, if possible.
+ * If the directory is unencrypted this is simply @iname.  Else, if we have the
+ * directory's encryption key, then @iname is the plaintext, so we encrypt it to
+ * get the disk_name.
+ *
+ * Else, for keyless @lookup operations, @iname is the presented ciphertext, so
+ * we decode it to get either the ciphertext disk_name (for short names) or the
+ * fscrypt_digested_name (for long names).  Non-@lookup operations will be
+ * impossible in this case, so we fail them with ENOKEY.
+ *
+ * If successful, fscrypt_free_filename() must be called later to clean up.
+ *
+ * Return: 0 on success, -errno on failure
+ */
 int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 			      int lookup, struct fscrypt_name *fname)
 {
-	int ret = 0, bigname = 0;
+	int ret;
+	int digested;
 
 	memset(fname, 0, sizeof(struct fscrypt_name));
 	fname->usr_fname = iname;
@@ -350,7 +388,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 		fname->disk_name.len = iname->len;
 		return 0;
 	}
-	ret = get_crypt_info(dir);
+	ret = fscrypt_get_encryption_info(dir);
 	if (ret && ret != -EOPNOTSUPP)
 		return ret;
 
@@ -367,31 +405,43 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 		return 0;
 	}
 	if (!lookup)
-		return -EACCES;
+		return -ENOKEY;
 
 	/*
 	 * We don't have the key and we are doing a lookup; decode the
 	 * user-supplied name
 	 */
-	if (iname->name[0] == '_')
-		bigname = 1;
-	if ((bigname && (iname->len != 33)) || (!bigname && (iname->len > 43)))
-		return -ENOENT;
+	if (iname->name[0] == '_') {
+		if (iname->len !=
+		    1 + BASE64_CHARS(sizeof(struct fscrypt_digested_name)))
+			return -ENOENT;
+		digested = 1;
+	} else {
+		if (iname->len >
+		    BASE64_CHARS(FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE))
+			return -ENOENT;
+		digested = 0;
+	}
 
-	fname->crypto_buf.name = kmalloc(32, GFP_KERNEL);
+	fname->crypto_buf.name =
+		kmalloc(max_t(size_t, FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE,
+			      sizeof(struct fscrypt_digested_name)),
+			GFP_KERNEL);
 	if (fname->crypto_buf.name == NULL)
 		return -ENOMEM;
 
-	ret = digest_decode(iname->name + bigname, iname->len - bigname,
+	ret = digest_decode(iname->name + digested, iname->len - digested,
 				fname->crypto_buf.name);
 	if (ret < 0) {
 		ret = -ENOENT;
 		goto errout;
 	}
 	fname->crypto_buf.len = ret;
-	if (bigname) {
-		memcpy(&fname->hash, fname->crypto_buf.name, 4);
-		memcpy(&fname->minor_hash, fname->crypto_buf.name + 4, 4);
+	if (digested) {
+		const struct fscrypt_digested_name *n =
+			(const void *)fname->crypto_buf.name;
+		fname->hash = n->hash;
+		fname->minor_hash = n->minor_hash;
 	} else {
 		fname->disk_name.name = fname->crypto_buf.name;
 		fname->disk_name.len = fname->crypto_buf.len;
@@ -403,12 +453,3 @@ errout:
 	return ret;
 }
 EXPORT_SYMBOL(fscrypt_setup_filename);
-
-void fscrypt_free_filename(struct fscrypt_name *fname)
-{
-	kfree(fname->crypto_buf.name);
-	fname->crypto_buf.name = NULL;
-	fname->usr_fname = NULL;
-	fname->disk_name.name = NULL;
-}
-EXPORT_SYMBOL(fscrypt_free_filename);
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
new file mode 100644
index 000000000000..79d79755d79b
--- /dev/null
+++ b/fs/crypto/fscrypt_private.h
@@ -0,0 +1,107 @@
+/*
+ * fscrypt_private.h
+ *
+ * Copyright (C) 2015, Google, Inc.
+ *
+ * This contains encryption key functions.
+ *
+ * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
+ */
+
+#ifndef _FSCRYPT_PRIVATE_H
+#define _FSCRYPT_PRIVATE_H
+
+#include <linux/fscrypt_supp.h>
+#include <crypto/hash.h>
+
+/* Encryption parameters */
+#define FS_IV_SIZE			16
+#define FS_AES_128_ECB_KEY_SIZE		16
+#define FS_AES_128_CBC_KEY_SIZE		16
+#define FS_AES_128_CTS_KEY_SIZE		16
+#define FS_AES_256_GCM_KEY_SIZE		32
+#define FS_AES_256_CBC_KEY_SIZE		32
+#define FS_AES_256_CTS_KEY_SIZE		32
+#define FS_AES_256_XTS_KEY_SIZE		64
+
+#define FS_KEY_DERIVATION_NONCE_SIZE		16
+
+/**
+ * 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: Flags
+ *  8 bytes: Master Key descriptor
+ *  16 bytes: Encryption Key derivation nonce
+ */
+struct fscrypt_context {
+	u8 format;
+	u8 contents_encryption_mode;
+	u8 filenames_encryption_mode;
+	u8 flags;
+	u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+	u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+} __packed;
+
+#define FS_ENCRYPTION_CONTEXT_FORMAT_V1		1
+
+/*
+ * A pointer to this structure is stored in the file system's in-core
+ * representation of an inode.
+ */
+struct fscrypt_info {
+	u8 ci_data_mode;
+	u8 ci_filename_mode;
+	u8 ci_flags;
+	struct crypto_skcipher *ci_ctfm;
+	struct crypto_cipher *ci_essiv_tfm;
+	u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
+};
+
+typedef enum {
+	FS_DECRYPT = 0,
+	FS_ENCRYPT,
+} fscrypt_direction_t;
+
+#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL		0x00000001
+#define FS_CTX_HAS_BOUNCE_BUFFER_FL		0x00000002
+
+struct fscrypt_completion_result {
+	struct completion completion;
+	int res;
+};
+
+#define DECLARE_FS_COMPLETION_RESULT(ecr) \
+	struct fscrypt_completion_result ecr = { \
+		COMPLETION_INITIALIZER_ONSTACK((ecr).completion), 0 }
+
+/* bio stuffs */
+#define REQ_OP_READ	READ
+#define REQ_OP_WRITE	WRITE
+#define bio_op(bio)	((bio)->bi_rw & 1)
+
+static inline void bio_set_op_attrs(struct bio *bio, unsigned op,
+		unsigned op_flags)
+{
+	bio->bi_rw = op | op_flags;
+}
+
+/* crypto.c */
+extern int fscrypt_initialize(unsigned int cop_flags);
+extern struct workqueue_struct *fscrypt_read_workqueue;
+extern int fscrypt_do_page_crypto(const struct inode *inode,
+				  fscrypt_direction_t rw, u64 lblk_num,
+				  struct page *src_page,
+				  struct page *dest_page,
+				  unsigned int len, unsigned int offs,
+				  gfp_t gfp_flags);
+extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
+					      gfp_t gfp_flags);
+
+/* keyinfo.c */
+extern void __exit fscrypt_essiv_cleanup(void);
+
+#endif /* _FSCRYPT_PRIVATE_H */
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 67fb6d8876d0..66e0728e9bbe 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -10,7 +10,12 @@
 
 #include <keys/user-type.h>
 #include <linux/scatterlist.h>
-#include <linux/fscrypto.h>
+#include <linux/ratelimit.h>
+#include <crypto/aes.h>
+#include <crypto/sha.h>
+#include "fscrypt_private.h"
+
+static struct crypto_shash *essiv_hash_tfm;
 
 static void derive_crypt_complete(struct crypto_async_request *req, int rc)
 {
@@ -27,13 +32,13 @@ static void derive_crypt_complete(struct crypto_async_request *req, int rc)
  * 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.
+ * @derived_raw_key:  Derived raw key.
  *
  * Return: Zero on success; non-zero otherwise.
  */
 static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
-				u8 source_key[FS_AES_256_XTS_KEY_SIZE],
-				u8 derived_key[FS_AES_256_XTS_KEY_SIZE])
+				const struct fscrypt_key *source_key,
+				u8 derived_raw_key[FS_MAX_KEY_SIZE])
 {
 	int res = 0;
 	struct skcipher_request *req = NULL;
@@ -60,10 +65,10 @@ static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
 	if (res < 0)
 		goto out;
 
-	sg_init_one(&src_sg, source_key, FS_AES_256_XTS_KEY_SIZE);
-	sg_init_one(&dst_sg, derived_key, FS_AES_256_XTS_KEY_SIZE);
-	skcipher_request_set_crypt(req, &src_sg, &dst_sg,
-					FS_AES_256_XTS_KEY_SIZE, NULL);
+	sg_init_one(&src_sg, source_key->raw, source_key->size);
+	sg_init_one(&dst_sg, derived_raw_key, source_key->size);
+	skcipher_request_set_crypt(req, &src_sg, &dst_sg, source_key->size,
+				   NULL);
 	res = crypto_skcipher_encrypt(req);
 	if (res == -EINPROGRESS || res == -EBUSY) {
 		wait_for_completion(&ecr.completion);
@@ -77,28 +82,25 @@ out:
 
 static int validate_user_key(struct fscrypt_info *crypt_info,
 			struct fscrypt_context *ctx, u8 *raw_key,
-			u8 *prefix, int prefix_size)
+			const char *prefix, int min_keysize)
 {
-	u8 *full_key_descriptor;
+	char *description;
 	struct key *keyring_key;
 	struct fscrypt_key *master_key;
 	const struct user_key_payload *ukp;
-	int full_key_len = prefix_size + (FS_KEY_DESCRIPTOR_SIZE * 2) + 1;
 	int res;
 
-	full_key_descriptor = kmalloc(full_key_len, GFP_NOFS);
-	if (!full_key_descriptor)
+	description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
+				FS_KEY_DESCRIPTOR_SIZE,
+				ctx->master_key_descriptor);
+	if (!description)
 		return -ENOMEM;
 
-	memcpy(full_key_descriptor, prefix, prefix_size);
-	sprintf(full_key_descriptor + prefix_size,
-			"%*phN", FS_KEY_DESCRIPTOR_SIZE,
-			ctx->master_key_descriptor);
-	full_key_descriptor[full_key_len - 1] = '\0';
-	keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
-	kfree(full_key_descriptor);
+	keyring_key = request_key(&key_type_logon, description, NULL);
+	kfree(description);
 	if (IS_ERR(keyring_key))
 		return PTR_ERR(keyring_key);
+	down_read(&keyring_key->sem);
 
 	if (keyring_key->type != &key_type_logon) {
 		printk_once(KERN_WARNING
@@ -106,66 +108,68 @@ static int validate_user_key(struct fscrypt_info *crypt_info,
 		res = -ENOKEY;
 		goto out;
 	}
-	down_read(&keyring_key->sem);
 	ukp = user_key_payload(keyring_key);
 	if (ukp->datalen != sizeof(struct fscrypt_key)) {
 		res = -EINVAL;
-		up_read(&keyring_key->sem);
 		goto out;
 	}
 	master_key = (struct fscrypt_key *)ukp->data;
 	BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE);
 
-	if (master_key->size != FS_AES_256_XTS_KEY_SIZE) {
+	if (master_key->size < min_keysize || master_key->size > FS_MAX_KEY_SIZE
+	    || master_key->size % AES_BLOCK_SIZE != 0) {
 		printk_once(KERN_WARNING
 				"%s: key size incorrect: %d\n",
 				__func__, master_key->size);
 		res = -ENOKEY;
-		up_read(&keyring_key->sem);
 		goto out;
 	}
-	res = derive_key_aes(ctx->nonce, master_key->raw, raw_key);
-	up_read(&keyring_key->sem);
-	if (res)
-		goto out;
-
-	crypt_info->ci_keyring_key = keyring_key;
-	return 0;
+	res = derive_key_aes(ctx->nonce, master_key, raw_key);
 out:
+	up_read(&keyring_key->sem);
 	key_put(keyring_key);
 	return res;
 }
 
+static const struct {
+	const char *cipher_str;
+	int keysize;
+} available_modes[] = {
+	[FS_ENCRYPTION_MODE_AES_256_XTS] = { "xts(aes)",
+					     FS_AES_256_XTS_KEY_SIZE },
+	[FS_ENCRYPTION_MODE_AES_256_CTS] = { "cts(cbc(aes))",
+					     FS_AES_256_CTS_KEY_SIZE },
+	[FS_ENCRYPTION_MODE_AES_128_CBC] = { "cbc(aes)",
+					     FS_AES_128_CBC_KEY_SIZE },
+	[FS_ENCRYPTION_MODE_AES_128_CTS] = { "cts(cbc(aes))",
+					     FS_AES_128_CTS_KEY_SIZE },
+};
+
 static int determine_cipher_type(struct fscrypt_info *ci, struct inode *inode,
 				 const char **cipher_str_ret, int *keysize_ret)
 {
-	if (S_ISREG(inode->i_mode)) {
-		if (ci->ci_data_mode == FS_ENCRYPTION_MODE_AES_256_XTS) {
-			*cipher_str_ret = "xts(aes)";
-			*keysize_ret = FS_AES_256_XTS_KEY_SIZE;
-			return 0;
-		}
-		pr_warn_once("fscrypto: unsupported contents encryption mode "
-			     "%d for inode %lu\n",
-			     ci->ci_data_mode, inode->i_ino);
-		return -ENOKEY;
+	u32 mode;
+
+	if (!fscrypt_valid_enc_modes(ci->ci_data_mode, ci->ci_filename_mode)) {
+		pr_warn_ratelimited("fscrypt: inode %lu uses unsupported encryption modes (contents mode %d, filenames mode %d)\n",
+				    inode->i_ino,
+				    ci->ci_data_mode, ci->ci_filename_mode);
+		return -EINVAL;
 	}
 
-	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) {
-		if (ci->ci_filename_mode == FS_ENCRYPTION_MODE_AES_256_CTS) {
-			*cipher_str_ret = "cts(cbc(aes))";
-			*keysize_ret = FS_AES_256_CTS_KEY_SIZE;
-			return 0;
-		}
-		pr_warn_once("fscrypto: unsupported filenames encryption mode "
-			     "%d for inode %lu\n",
-			     ci->ci_filename_mode, inode->i_ino);
-		return -ENOKEY;
+	if (S_ISREG(inode->i_mode)) {
+		mode = ci->ci_data_mode;
+	} else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) {
+		mode = ci->ci_filename_mode;
+	} else {
+		WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
+			  inode->i_ino, (inode->i_mode & S_IFMT));
+		return -EINVAL;
 	}
 
-	pr_warn_once("fscrypto: unsupported file type %d for inode %lu\n",
-		     (inode->i_mode & S_IFMT), inode->i_ino);
-	return -ENOKEY;
+	*cipher_str_ret = available_modes[mode].cipher_str;
+	*keysize_ret = available_modes[mode].keysize;
+	return 0;
 }
 
 static void put_crypt_info(struct fscrypt_info *ci)
@@ -173,12 +177,78 @@ static void put_crypt_info(struct fscrypt_info *ci)
 	if (!ci)
 		return;
 
-	key_put(ci->ci_keyring_key);
 	crypto_free_skcipher(ci->ci_ctfm);
+	crypto_free_cipher(ci->ci_essiv_tfm);
 	kmem_cache_free(fscrypt_info_cachep, ci);
 }
 
-int get_crypt_info(struct inode *inode)
+static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt)
+{
+	struct crypto_shash *tfm = READ_ONCE(essiv_hash_tfm);
+
+	/* init hash transform on demand */
+	if (unlikely(!tfm)) {
+		struct crypto_shash *prev_tfm;
+
+		tfm = crypto_alloc_shash("sha256", 0, 0);
+		if (IS_ERR(tfm)) {
+			pr_warn_ratelimited("fscrypt: error allocating SHA-256 transform: %ld\n",
+					    PTR_ERR(tfm));
+			return PTR_ERR(tfm);
+		}
+		prev_tfm = cmpxchg(&essiv_hash_tfm, NULL, tfm);
+		if (prev_tfm) {
+			crypto_free_shash(tfm);
+			tfm = prev_tfm;
+		}
+	}
+
+	{
+		SHASH_DESC_ON_STACK(desc, tfm);
+		desc->tfm = tfm;
+		desc->flags = 0;
+
+		return crypto_shash_digest(desc, key, keysize, salt);
+	}
+}
+
+static int init_essiv_generator(struct fscrypt_info *ci, const u8 *raw_key,
+				int keysize)
+{
+	int err;
+	struct crypto_cipher *essiv_tfm;
+	u8 salt[SHA256_DIGEST_SIZE];
+
+	essiv_tfm = crypto_alloc_cipher("aes", 0, 0);
+	if (IS_ERR(essiv_tfm))
+		return PTR_ERR(essiv_tfm);
+
+	ci->ci_essiv_tfm = essiv_tfm;
+
+	err = derive_essiv_salt(raw_key, keysize, salt);
+	if (err)
+		goto out;
+
+	/*
+	 * Using SHA256 to derive the salt/key will result in AES-256 being
+	 * used for IV generation. File contents encryption will still use the
+	 * configured keysize (AES-128) nevertheless.
+	 */
+	err = crypto_cipher_setkey(essiv_tfm, salt, sizeof(salt));
+	if (err)
+		goto out;
+
+out:
+	memzero_explicit(salt, sizeof(salt));
+	return err;
+}
+
+void __exit fscrypt_essiv_cleanup(void)
+{
+	crypto_free_shash(essiv_hash_tfm);
+}
+
+int fscrypt_get_encryption_info(struct inode *inode)
 {
 	struct fscrypt_info *crypt_info;
 	struct fscrypt_context ctx;
@@ -188,30 +258,24 @@ int get_crypt_info(struct inode *inode)
 	u8 *raw_key = NULL;
 	int res;
 
-	res = fscrypt_initialize();
+	if (inode->i_crypt_info)
+		return 0;
+
+	res = fscrypt_initialize(inode->i_sb->s_cop->flags);
 	if (res)
 		return res;
 
-	if (!inode->i_sb->s_cop->get_context)
-		return -EOPNOTSUPP;
-retry:
-	crypt_info = ACCESS_ONCE(inode->i_crypt_info);
-	if (crypt_info) {
-		if (!crypt_info->ci_keyring_key ||
-				key_validate(crypt_info->ci_keyring_key) == 0)
-			return 0;
-		fscrypt_put_encryption_info(inode, crypt_info);
-		goto retry;
-	}
-
 	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
 	if (res < 0) {
-		if (!fscrypt_dummy_context_enabled(inode))
+		if (!fscrypt_dummy_context_enabled(inode) ||
+		    inode->i_sb->s_cop->is_encrypted(inode))
 			return res;
+		/* Fake up a context for an unencrypted directory */
+		memset(&ctx, 0, sizeof(ctx));
 		ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
 		ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
 		ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
-		ctx.flags = 0;
+		memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
 	} else if (res != sizeof(ctx)) {
 		return -EINVAL;
 	}
@@ -230,7 +294,7 @@ retry:
 	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;
+	crypt_info->ci_essiv_tfm = NULL;
 	memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
 				sizeof(crypt_info->ci_master_key));
 
@@ -247,20 +311,12 @@ retry:
 	if (!raw_key)
 		goto out;
 
-	if (fscrypt_dummy_context_enabled(inode)) {
-		memset(raw_key, 0x42, FS_AES_256_XTS_KEY_SIZE);
-		goto got_key;
-	}
-
-	res = validate_user_key(crypt_info, &ctx, raw_key,
-			FS_KEY_DESC_PREFIX, FS_KEY_DESC_PREFIX_SIZE);
+	res = validate_user_key(crypt_info, &ctx, raw_key, FS_KEY_DESC_PREFIX,
+				keysize);
 	if (res && inode->i_sb->s_cop->key_prefix) {
-		u8 *prefix = NULL;
-		int prefix_size, res2;
-
-		prefix_size = inode->i_sb->s_cop->key_prefix(inode, &prefix);
-		res2 = validate_user_key(crypt_info, &ctx, raw_key,
-							prefix, prefix_size);
+		int res2 = validate_user_key(crypt_info, &ctx, raw_key,
+					     inode->i_sb->s_cop->key_prefix,
+					     keysize);
 		if (res2) {
 			if (res2 == -ENOKEY)
 				res = -ENOKEY;
@@ -269,30 +325,35 @@ retry:
 	} else 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);
+		pr_debug("%s: error %d (inode %lu) allocating crypto tfm\n",
+			 __func__, res, inode->i_ino);
 		goto out;
 	}
 	crypt_info->ci_ctfm = ctfm;
 	crypto_skcipher_clear_flags(ctfm, ~0);
 	crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY);
+	/*
+	 * if the provided key is longer than keysize, we use the first
+	 * keysize bytes of the derived key only
+	 */
 	res = crypto_skcipher_setkey(ctfm, raw_key, keysize);
 	if (res)
 		goto out;
 
-	kzfree(raw_key);
-	raw_key = NULL;
-	if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) != NULL) {
-		put_crypt_info(crypt_info);
-		goto retry;
+	if (S_ISREG(inode->i_mode) &&
+	    crypt_info->ci_data_mode == FS_ENCRYPTION_MODE_AES_128_CBC) {
+		res = init_essiv_generator(crypt_info, raw_key, keysize);
+		if (res) {
+			pr_debug("%s: error %d (inode %lu) allocating essiv tfm\n",
+				 __func__, res, inode->i_ino);
+			goto out;
+		}
 	}
-	return 0;
-
+	if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) == NULL)
+		crypt_info = NULL;
 out:
 	if (res == -ENOKEY)
 		res = 0;
@@ -300,6 +361,7 @@ out:
 	kzfree(raw_key);
 	return res;
 }
+EXPORT_SYMBOL(fscrypt_get_encryption_info);
 
 void fscrypt_put_encryption_info(struct inode *inode, struct fscrypt_info *ci)
 {
@@ -317,17 +379,3 @@ void fscrypt_put_encryption_info(struct inode *inode, struct fscrypt_info *ci)
 	put_crypt_info(ci);
 }
 EXPORT_SYMBOL(fscrypt_put_encryption_info);
-
-int fscrypt_get_encryption_info(struct inode *inode)
-{
-	struct fscrypt_info *ci = inode->i_crypt_info;
-
-	if (!ci ||
-		(ci->ci_keyring_key &&
-		 (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
-					       (1 << KEY_FLAG_REVOKED) |
-					       (1 << KEY_FLAG_DEAD)))))
-		return get_crypt_info(inode);
-	return 0;
-}
-EXPORT_SYMBOL(fscrypt_get_encryption_info);
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 6865663aac69..9914d51dff86 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -10,76 +10,37 @@
 
 #include <linux/random.h>
 #include <linux/string.h>
-#include <linux/fscrypto.h>
 #include <linux/mount.h>
-
-static int inode_has_encryption_context(struct inode *inode)
-{
-	if (!inode->i_sb->s_cop->get_context)
-		return 0;
-	return (inode->i_sb->s_cop->get_context(inode, NULL, 0L) > 0);
-}
+#include "fscrypt_private.h"
 
 /*
- * check whether the policy is consistent with the encryption context
- * for the inode
+ * check whether an encryption policy is consistent with an encryption context
  */
-static int is_encryption_context_consistent_with_policy(struct inode *inode,
+static bool is_encryption_context_consistent_with_policy(
+				const struct fscrypt_context *ctx,
 				const struct fscrypt_policy *policy)
 {
-	struct fscrypt_context ctx;
-	int res;
-
-	if (!inode->i_sb->s_cop->get_context)
-		return 0;
-
-	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
-	if (res != sizeof(ctx))
-		return 0;
-
-	return (memcmp(ctx.master_key_descriptor, policy->master_key_descriptor,
-			FS_KEY_DESCRIPTOR_SIZE) == 0 &&
-			(ctx.flags == policy->flags) &&
-			(ctx.contents_encryption_mode ==
-			 policy->contents_encryption_mode) &&
-			(ctx.filenames_encryption_mode ==
-			 policy->filenames_encryption_mode));
+	return memcmp(ctx->master_key_descriptor, policy->master_key_descriptor,
+		      FS_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 create_encryption_context_from_policy(struct inode *inode,
 				const struct fscrypt_policy *policy)
 {
 	struct fscrypt_context ctx;
-	int res;
-
-	if (!inode->i_sb->s_cop->set_context)
-		return -EOPNOTSUPP;
-
-	if (inode->i_sb->s_cop->prepare_context) {
-		res = inode->i_sb->s_cop->prepare_context(inode);
-		if (res)
-			return res;
-	}
 
 	ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
 	memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
 					FS_KEY_DESCRIPTOR_SIZE);
 
-	if (!fscrypt_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 (!fscrypt_valid_filenames_enc_mode(
-				policy->filenames_encryption_mode)) {
-		printk(KERN_WARNING
-			"%s: Invalid filenames encryption mode %d\n", __func__,
-			policy->filenames_encryption_mode);
+	if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
+				     policy->filenames_encryption_mode))
 		return -EINVAL;
-	}
 
 	if (policy->flags & ~FS_POLICY_FLAGS_VALID)
 		return -EINVAL;
@@ -93,16 +54,20 @@ static int create_encryption_context_from_policy(struct inode *inode,
 	return inode->i_sb->s_cop->set_context(inode, &ctx, sizeof(ctx), NULL);
 }
 
-int fscrypt_process_policy(struct file *filp,
-				const struct fscrypt_policy *policy)
+int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
 {
+	struct fscrypt_policy policy;
 	struct inode *inode = file_inode(filp);
 	int ret;
+	struct fscrypt_context ctx;
+
+	if (copy_from_user(&policy, arg, sizeof(policy)))
+		return -EFAULT;
 
 	if (!inode_owner_or_capable(inode))
 		return -EACCES;
 
-	if (policy->version != 0)
+	if (policy.version != 0)
 		return -EINVAL;
 
 	ret = mnt_want_write_file(filp);
@@ -111,22 +76,23 @@ int fscrypt_process_policy(struct file *filp,
 
 	inode_lock(inode);
 
-	if (!inode_has_encryption_context(inode)) {
+	ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+	if (ret == -ENODATA) {
 		if (!S_ISDIR(inode->i_mode))
-			ret = -EINVAL;
-		else if (!inode->i_sb->s_cop->empty_dir)
-			ret = -EOPNOTSUPP;
+			ret = -ENOTDIR;
 		else if (!inode->i_sb->s_cop->empty_dir(inode))
 			ret = -ENOTEMPTY;
 		else
 			ret = create_encryption_context_from_policy(inode,
-								    policy);
-	} else if (!is_encryption_context_consistent_with_policy(inode,
-								 policy)) {
-		printk(KERN_WARNING
-		       "%s: Policy inconsistent with encryption context\n",
-		       __func__);
-		ret = -EINVAL;
+								    &policy);
+	} else if (ret == sizeof(ctx) &&
+		   is_encryption_context_consistent_with_policy(&ctx,
+								&policy)) {
+		/* The file already uses the same encryption policy. */
+		ret = 0;
+	} else if (ret >= 0 || ret == -ERANGE) {
+		/* The file already uses a different encryption policy. */
+		ret = -EEXIST;
 	}
 
 	inode_unlock(inode);
@@ -134,49 +100,94 @@ int fscrypt_process_policy(struct file *filp,
 	mnt_drop_write_file(filp);
 	return ret;
 }
-EXPORT_SYMBOL(fscrypt_process_policy);
+EXPORT_SYMBOL(fscrypt_ioctl_set_policy);
 
-int fscrypt_get_policy(struct inode *inode, struct fscrypt_policy *policy)
+int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
 {
+	struct inode *inode = file_inode(filp);
 	struct fscrypt_context ctx;
+	struct fscrypt_policy policy;
 	int res;
 
-	if (!inode->i_sb->s_cop->get_context ||
-			!inode->i_sb->s_cop->is_encrypted(inode))
+	if (!inode->i_sb->s_cop->is_encrypted(inode))
 		return -ENODATA;
 
 	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+	if (res < 0 && res != -ERANGE)
+		return res;
 	if (res != sizeof(ctx))
-		return -ENODATA;
+		return -EINVAL;
 	if (ctx.format != FS_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,
+	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,
 				FS_KEY_DESCRIPTOR_SIZE);
+
+	if (copy_to_user(arg, &policy, sizeof(policy)))
+		return -EFAULT;
 	return 0;
 }
-EXPORT_SYMBOL(fscrypt_get_policy);
+EXPORT_SYMBOL(fscrypt_ioctl_get_policy);
 
+/**
+ * fscrypt_has_permitted_context() - is a file's encryption policy permitted
+ *				     within its directory?
+ *
+ * @parent: inode for parent directory
+ * @child: inode for file being looked up, opened, or linked into @parent
+ *
+ * Filesystems must call this before permitting access to an inode in a
+ * situation where the parent directory is encrypted (either before allowing
+ * ->lookup() to succeed, or for a regular file before allowing it to be opened)
+ * and before any operation that involves linking an inode into an encrypted
+ * directory, including link, rename, and cross rename.  It enforces the
+ * constraint that within a given encrypted directory tree, all files use the
+ * same encryption policy.  The pre-access check is needed to detect potentially
+ * malicious offline violations of this constraint, while the link and rename
+ * checks are needed to prevent online violations of this constraint.
+ *
+ * Return: 1 if permitted, 0 if forbidden.  If forbidden, the caller must fail
+ * the filesystem operation with EPERM.
+ */
 int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
 {
-	struct fscrypt_info *parent_ci, *child_ci;
+	const struct fscrypt_operations *cops = parent->i_sb->s_cop;
+	const struct fscrypt_info *parent_ci, *child_ci;
+	struct fscrypt_context parent_ctx, child_ctx;
 	int res;
 
-	if ((parent == NULL) || (child == NULL)) {
-		printk(KERN_ERR	"parent %p child %p\n", parent, child);
-		BUG_ON(1);
-	}
+	/* No restrictions on file types which are never encrypted */
+	if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) &&
+	    !S_ISLNK(child->i_mode))
+		return 1;
 
-	/* no restrictions if the parent directory is not encrypted */
-	if (!parent->i_sb->s_cop->is_encrypted(parent))
+	/* No restrictions if the parent directory is unencrypted */
+	if (!cops->is_encrypted(parent))
 		return 1;
-	/* if the child directory is not encrypted, this is always a problem */
-	if (!parent->i_sb->s_cop->is_encrypted(child))
+
+	/* Encrypted directories must not contain unencrypted files */
+	if (!cops->is_encrypted(child))
 		return 0;
+
+	/*
+	 * Both parent and child are encrypted, so verify they use the same
+	 * encryption policy.  Compare the fscrypt_info structs if the keys are
+	 * available, otherwise retrieve and compare the fscrypt_contexts.
+	 *
+	 * Note that the fscrypt_context retrieval will be required frequently
+	 * when accessing an encrypted directory tree without the key.
+	 * Performance-wise this is not a big deal because we already don't
+	 * really optimize for file access without the key (to the extent that
+	 * such access is even possible), given that any attempted access
+	 * already causes a fscrypt_context retrieval and keyring search.
+	 *
+	 * In any case, if an unexpected error occurs, fall back to "forbidden".
+	 */
+
 	res = fscrypt_get_encryption_info(parent);
 	if (res)
 		return 0;
@@ -185,17 +196,32 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
 		return 0;
 	parent_ci = parent->i_crypt_info;
 	child_ci = child->i_crypt_info;
-	if (!parent_ci && !child_ci)
-		return 1;
-	if (!parent_ci || !child_ci)
+
+	if (parent_ci && child_ci) {
+		return memcmp(parent_ci->ci_master_key, child_ci->ci_master_key,
+			      FS_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);
+	}
+
+	res = cops->get_context(parent, &parent_ctx, sizeof(parent_ctx));
+	if (res != sizeof(parent_ctx))
+		return 0;
+
+	res = cops->get_context(child, &child_ctx, sizeof(child_ctx));
+	if (res != sizeof(child_ctx))
 		return 0;
 
-	return (memcmp(parent_ci->ci_master_key,
-			child_ci->ci_master_key,
-			FS_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));
+	return memcmp(parent_ctx.master_key_descriptor,
+		      child_ctx.master_key_descriptor,
+		      FS_KEY_DESCRIPTOR_SIZE) == 0 &&
+		(parent_ctx.contents_encryption_mode ==
+		 child_ctx.contents_encryption_mode) &&
+		(parent_ctx.filenames_encryption_mode ==
+		 child_ctx.filenames_encryption_mode) &&
+		(parent_ctx.flags == child_ctx.flags);
 }
 EXPORT_SYMBOL(fscrypt_has_permitted_context);
 
@@ -204,9 +230,9 @@ EXPORT_SYMBOL(fscrypt_has_permitted_context);
  * @parent: Parent inode from which the context is inherited.
  * @child:  Child inode that inherits the context from @parent.
  * @fs_data:  private data given by FS.
- * @preload:  preload child i_crypt_info
+ * @preload:  preload child i_crypt_info if true
  *
- * Return: Zero on success, non-zero otherwise
+ * Return: 0 on success, -errno on failure
  */
 int fscrypt_inherit_context(struct inode *parent, struct inode *child,
 						void *fs_data, bool preload)
@@ -215,9 +241,6 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child,
 	struct fscrypt_info *ci;
 	int res;
 
-	if (!parent->i_sb->s_cop->set_context)
-		return -EOPNOTSUPP;
-
 	res = fscrypt_get_encryption_info(parent);
 	if (res < 0)
 		return res;
@@ -227,19 +250,11 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child,
 		return -ENOKEY;
 
 	ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
-	if (fscrypt_dummy_context_enabled(parent)) {
-		ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
-		ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
-		ctx.flags = 0;
-		memset(ctx.master_key_descriptor, 0x42, FS_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,
-				FS_KEY_DESCRIPTOR_SIZE);
-	}
+	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,
+	       FS_KEY_DESCRIPTOR_SIZE);
 	get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
 	res = parent->i_sb->s_cop->set_context(child, &ctx,
 						sizeof(ctx), fs_data);