Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux

Pull fscrypt updates from Eric Biggers:
 "This update adds support for configuring the crypto data unit size
  (i.e. the granularity of file contents encryption) to be less than the
  filesystem block size. This can allow users to use inline encryption
  hardware in some cases when it wouldn't otherwise be possible.

  In addition, there are two commits that are prerequisites for the
  extent-based encryption support that the btrfs folks are working on"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux:
  fscrypt: track master key presence separately from secret
  fscrypt: rename fscrypt_info => fscrypt_inode_info
  fscrypt: support crypto data unit size less than filesystem block size
  fscrypt: replace get_ino_and_lblk_bits with just has_32bit_inodes
  fscrypt: compute max_lblk_bits from s_maxbytes and block size
  fscrypt: make the bounce page pool opt-in instead of opt-out
  fscrypt: make it clearer that key_prefix is deprecated

18 files changed, 546 insertions, 349 deletions

diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
index a624e92f2687..1b84f818e574 100644
--- a/Documentation/filesystems/fscrypt.rst
+++ b/Documentation/filesystems/fscrypt.rst
@@ -261,9 +261,9 @@ DIRECT_KEY policies
 
 The Adiantum encryption mode (see `Encryption modes and usage`_) is
 suitable for both contents and filenames encryption, and it accepts
-long IVs --- long enough to hold both an 8-byte logical block number
-and a 16-byte per-file nonce.  Also, the overhead of each Adiantum key
-is greater than that of an AES-256-XTS key.
+long IVs --- long enough to hold both an 8-byte data unit index and a
+16-byte per-file nonce.  Also, the overhead of each Adiantum key is
+greater than that of an AES-256-XTS key.
 
 Therefore, to improve performance and save memory, for Adiantum a
 "direct key" configuration is supported.  When the user has enabled
@@ -300,8 +300,8 @@ IV_INO_LBLK_32 policies
 
 IV_INO_LBLK_32 policies work like IV_INO_LBLK_64, except that for
 IV_INO_LBLK_32, the inode number is hashed with SipHash-2-4 (where the
-SipHash key is derived from the master key) and added to the file
-logical block number mod 2^32 to produce a 32-bit IV.
+SipHash key is derived from the master key) and added to the file data
+unit index mod 2^32 to produce a 32-bit IV.
 
 This format is optimized for use with inline encryption hardware
 compliant with the eMMC v5.2 standard, which supports only 32 IV bits
@@ -451,31 +451,62 @@ acceleration is recommended:
 Contents encryption
 -------------------
 
-For file contents, each filesystem block is encrypted independently.
-Starting from Linux kernel 5.5, encryption of filesystems with block
-size less than system's page size is supported.
-
-Each block's IV is set to the logical block number within the file as
-a little endian number, except that:
-
-- With CBC mode encryption, ESSIV is also used.  Specifically, each IV
-  is encrypted with AES-256 where the AES-256 key is the SHA-256 hash
-  of the file's data encryption key.
-
-- With `DIRECT_KEY policies`_, the file's nonce is appended to the IV.
-  Currently this is only allowed with the Adiantum encryption mode.
-
-- With `IV_INO_LBLK_64 policies`_, the logical block number is limited
-  to 32 bits and is placed in bits 0-31 of the IV.  The inode number
-  (which is also limited to 32 bits) is placed in bits 32-63.
-
-- With `IV_INO_LBLK_32 policies`_, the logical block number is limited
-  to 32 bits and is placed in bits 0-31 of the IV.  The inode number
-  is then hashed and added mod 2^32.
-
-Note that because file logical block numbers are included in the IVs,
-filesystems must enforce that blocks are never shifted around within
-encrypted files, e.g. via "collapse range" or "insert range".
+For contents encryption, each file's contents is divided into "data
+units".  Each data unit is encrypted independently.  The IV for each
+data unit incorporates the zero-based index of the data unit within
+the file.  This ensures that each data unit within a file is encrypted
+differently, which is essential to prevent leaking information.
+
+Note: the encryption depending on the offset into the file means that
+operations like "collapse range" and "insert range" that rearrange the
+extent mapping of files are not supported on encrypted files.
+
+There are two cases for the sizes of the data units:
+
+* Fixed-size data units.  This is how all filesystems other than UBIFS
+  work.  A file's data units are all the same size; the last data unit
+  is zero-padded if needed.  By default, the data unit size is equal
+  to the filesystem block size.  On some filesystems, users can select
+  a sub-block data unit size via the ``log2_data_unit_size`` field of
+  the encryption policy; see `FS_IOC_SET_ENCRYPTION_POLICY`_.
+
+* Variable-size data units.  This is what UBIFS does.  Each "UBIFS
+  data node" is treated as a crypto data unit.  Each contains variable
+  length, possibly compressed data, zero-padded to the next 16-byte
+  boundary.  Users cannot select a sub-block data unit size on UBIFS.
+
+In the case of compression + encryption, the compressed data is
+encrypted.  UBIFS compression works as described above.  f2fs
+compression works a bit differently; it compresses a number of
+filesystem blocks into a smaller number of filesystem blocks.
+Therefore a f2fs-compressed file still uses fixed-size data units, and
+it is encrypted in a similar way to a file containing holes.
+
+As mentioned in `Key hierarchy`_, the default encryption setting uses
+per-file keys.  In this case, the IV for each data unit is simply the
+index of the data unit in the file.  However, users can select an
+encryption setting that does not use per-file keys.  For these, some
+kind of file identifier is incorporated into the IVs as follows:
+
+- With `DIRECT_KEY policies`_, the data unit index is placed in bits
+  0-63 of the IV, and the file's nonce is placed in bits 64-191.
+
+- With `IV_INO_LBLK_64 policies`_, the data unit index is placed in
+  bits 0-31 of the IV, and the file's inode number is placed in bits
+  32-63.  This setting is only allowed when data unit indices and
+  inode numbers fit in 32 bits.
+
+- With `IV_INO_LBLK_32 policies`_, the file's inode number is hashed
+  and added to the data unit index.  The resulting value is truncated
+  to 32 bits and placed in bits 0-31 of the IV.  This setting is only
+  allowed when data unit indices and inode numbers fit in 32 bits.
+
+The byte order of the IV is always little endian.
+
+If the user selects FSCRYPT_MODE_AES_128_CBC for the contents mode, an
+ESSIV layer is automatically included.  In this case, before the IV is
+passed to AES-128-CBC, it is encrypted with AES-256 where the AES-256
+key is the SHA-256 hash of the file's contents encryption key.
 
 Filenames encryption
 --------------------
@@ -544,7 +575,8 @@ follows::
             __u8 contents_encryption_mode;
             __u8 filenames_encryption_mode;
             __u8 flags;
-            __u8 __reserved[4];
+            __u8 log2_data_unit_size;
+            __u8 __reserved[3];
             __u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
     };
 
@@ -586,6 +618,29 @@ This structure must be initialized as follows:
   The DIRECT_KEY, IV_INO_LBLK_64, and IV_INO_LBLK_32 flags are
   mutually exclusive.
 
+- ``log2_data_unit_size`` is the log2 of the data unit size in bytes,
+  or 0 to select the default data unit size.  The data unit size is
+  the granularity of file contents encryption.  For example, setting
+  ``log2_data_unit_size`` to 12 causes file contents be passed to the
+  underlying encryption algorithm (such as AES-256-XTS) in 4096-byte
+  data units, each with its own IV.
+
+  Not all filesystems support setting ``log2_data_unit_size``.  ext4
+  and f2fs support it since Linux v6.7.  On filesystems that support
+  it, the supported nonzero values are 9 through the log2 of the
+  filesystem block size, inclusively.  The default value of 0 selects
+  the filesystem block size.
+
+  The main use case for ``log2_data_unit_size`` is for selecting a
+  data unit size smaller than the filesystem block size for
+  compatibility with inline encryption hardware that only supports
+  smaller data unit sizes.  ``/sys/block/$disk/queue/crypto/`` may be
+  useful for checking which data unit sizes are supported by a
+  particular system's inline encryption hardware.
+
+  Leave this field zeroed unless you are certain you need it.  Using
+  an unnecessarily small data unit size reduces performance.
+
 - For v2 encryption policies, ``__reserved`` must be zeroed.
 
 - For v1 encryption policies, ``master_key_descriptor`` specifies how
@@ -1079,8 +1134,8 @@ The caller must zero all input fields, then fill in ``key_spec``:
 On success, 0 is returned and the kernel fills in the output fields:
 
 - ``status`` indicates whether the key is absent, present, or
-  incompletely removed.  Incompletely removed means that the master
-  secret has been removed, but some files are still in use; i.e.,
+  incompletely removed.  Incompletely removed means that removal has
+  been initiated, but some files are still in use; i.e.,
   `FS_IOC_REMOVE_ENCRYPTION_KEY`_ returned 0 but set the informational
   status flag FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY.
 
diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
index 5b5112c78462..e3b1c3fab412 100644
--- a/fs/ceph/crypto.c
+++ b/fs/ceph/crypto.c
@@ -133,6 +133,7 @@ static const union fscrypt_policy *ceph_get_dummy_policy(struct super_block *sb)
 }
 
 static struct fscrypt_operations ceph_fscrypt_ops = {
+	.needs_bounce_pages	= 1,
 	.get_context		= ceph_crypt_get_context,
 	.set_context		= ceph_crypt_set_context,
 	.get_dummy_policy	= ceph_get_dummy_policy,
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index 62e1a3dd8357..0ad8c30b8fa5 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -111,10 +111,14 @@ out:
 int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 			  sector_t pblk, unsigned int len)
 {
-	const unsigned int blockbits = inode->i_blkbits;
-	const unsigned int blocksize = 1 << blockbits;
-	const unsigned int blocks_per_page_bits = PAGE_SHIFT - blockbits;
-	const unsigned int blocks_per_page = 1 << blocks_per_page_bits;
+	const struct fscrypt_inode_info *ci = inode->i_crypt_info;
+	const unsigned int du_bits = ci->ci_data_unit_bits;
+	const unsigned int du_size = 1U << du_bits;
+	const unsigned int du_per_page_bits = PAGE_SHIFT - du_bits;
+	const unsigned int du_per_page = 1U << du_per_page_bits;
+	u64 du_index = (u64)lblk << (inode->i_blkbits - du_bits);
+	u64 du_remaining = (u64)len << (inode->i_blkbits - du_bits);
+	sector_t sector = pblk << (inode->i_blkbits - SECTOR_SHIFT);
 	struct page *pages[16]; /* write up to 16 pages at a time */
 	unsigned int nr_pages;
 	unsigned int i;
@@ -130,8 +134,8 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 							  len);
 
 	BUILD_BUG_ON(ARRAY_SIZE(pages) > BIO_MAX_VECS);
-	nr_pages = min_t(unsigned int, ARRAY_SIZE(pages),
-			 (len + blocks_per_page - 1) >> blocks_per_page_bits);
+	nr_pages = min_t(u64, ARRAY_SIZE(pages),
+			 (du_remaining + du_per_page - 1) >> du_per_page_bits);
 
 	/*
 	 * We need at least one page for ciphertext.  Allocate the first one
@@ -154,21 +158,22 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 	bio = bio_alloc(inode->i_sb->s_bdev, nr_pages, REQ_OP_WRITE, GFP_NOFS);
 
 	do {
-		bio->bi_iter.bi_sector = pblk << (blockbits - 9);
+		bio->bi_iter.bi_sector = sector;
 
 		i = 0;
 		offset = 0;
 		do {
-			err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk,
-						  ZERO_PAGE(0), pages[i],
-						  blocksize, offset, GFP_NOFS);
+			err = fscrypt_crypt_data_unit(ci, FS_ENCRYPT, du_index,
+						      ZERO_PAGE(0), pages[i],
+						      du_size, offset,
+						      GFP_NOFS);
 			if (err)
 				goto out;
-			lblk++;
-			pblk++;
-			len--;
-			offset += blocksize;
-			if (offset == PAGE_SIZE || len == 0) {
+			du_index++;
+			sector += 1U << (du_bits - SECTOR_SHIFT);
+			du_remaining--;
+			offset += du_size;
+			if (offset == PAGE_SIZE || du_remaining == 0) {
 				ret = bio_add_page(bio, pages[i++], offset, 0);
 				if (WARN_ON_ONCE(ret != offset)) {
 					err = -EIO;
@@ -176,13 +181,13 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 				}
 				offset = 0;
 			}
-		} while (i != nr_pages && len != 0);
+		} while (i != nr_pages && du_remaining != 0);
 
 		err = submit_bio_wait(bio);
 		if (err)
 			goto out;
 		bio_reset(bio, inode->i_sb->s_bdev, REQ_OP_WRITE);
-	} while (len != 0);
+	} while (du_remaining != 0);
 	err = 0;
 out:
 	bio_put(bio);
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 6a837e4b80dc..328470d40dec 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -39,7 +39,7 @@ static mempool_t *fscrypt_bounce_page_pool = NULL;
 static struct workqueue_struct *fscrypt_read_workqueue;
 static DEFINE_MUTEX(fscrypt_init_mutex);
 
-struct kmem_cache *fscrypt_info_cachep;
+struct kmem_cache *fscrypt_inode_info_cachep;
 
 void fscrypt_enqueue_decrypt_work(struct work_struct *work)
 {
@@ -49,6 +49,13 @@ EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work);
 
 struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags)
 {
+	if (WARN_ON_ONCE(!fscrypt_bounce_page_pool)) {
+		/*
+		 * Oops, the filesystem called a function that uses the bounce
+		 * page pool, but it didn't set needs_bounce_pages.
+		 */
+		return NULL;
+	}
 	return mempool_alloc(fscrypt_bounce_page_pool, gfp_flags);
 }
 
@@ -70,44 +77,44 @@ void fscrypt_free_bounce_page(struct page *bounce_page)
 EXPORT_SYMBOL(fscrypt_free_bounce_page);
 
 /*
- * Generate the IV for the given logical block number within the given file.
- * For filenames encryption, lblk_num == 0.
+ * Generate the IV for the given data unit index within the given file.
+ * For filenames encryption, index == 0.
  *
  * Keep this in sync with fscrypt_limit_io_blocks().  fscrypt_limit_io_blocks()
  * needs to know about any IV generation methods where the low bits of IV don't
- * simply contain the lblk_num (e.g., IV_INO_LBLK_32).
+ * simply contain the data unit index (e.g., IV_INO_LBLK_32).
  */
-void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
-			 const struct fscrypt_info *ci)
+void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index,
+			 const struct fscrypt_inode_info *ci)
 {
 	u8 flags = fscrypt_policy_flags(&ci->ci_policy);
 
 	memset(iv, 0, ci->ci_mode->ivsize);
 
 	if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) {
-		WARN_ON_ONCE(lblk_num > U32_MAX);
+		WARN_ON_ONCE(index > U32_MAX);
 		WARN_ON_ONCE(ci->ci_inode->i_ino > U32_MAX);
-		lblk_num |= (u64)ci->ci_inode->i_ino << 32;
+		index |= (u64)ci->ci_inode->i_ino << 32;
 	} else if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) {
-		WARN_ON_ONCE(lblk_num > U32_MAX);
-		lblk_num = (u32)(ci->ci_hashed_ino + lblk_num);
+		WARN_ON_ONCE(index > U32_MAX);
+		index = (u32)(ci->ci_hashed_ino + index);
 	} else if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {
 		memcpy(iv->nonce, ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE);
 	}
-	iv->lblk_num = cpu_to_le64(lblk_num);
+	iv->index = cpu_to_le64(index);
 }
 
-/* Encrypt or decrypt a single filesystem block of file contents */
-int fscrypt_crypt_block(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)
+/* Encrypt or decrypt a single "data unit" of file contents. */
+int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
+			    fscrypt_direction_t rw, u64 index,
+			    struct page *src_page, struct page *dest_page,
+			    unsigned int len, unsigned int offs,
+			    gfp_t gfp_flags)
 {
 	union fscrypt_iv iv;
 	struct skcipher_request *req = NULL;
 	DECLARE_CRYPTO_WAIT(wait);
 	struct scatterlist dst, src;
-	struct fscrypt_info *ci = inode->i_crypt_info;
 	struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
 	int res = 0;
 
@@ -116,7 +123,7 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw,
 	if (WARN_ON_ONCE(len % FSCRYPT_CONTENTS_ALIGNMENT != 0))
 		return -EINVAL;
 
-	fscrypt_generate_iv(&iv, lblk_num, ci);
+	fscrypt_generate_iv(&iv, index, ci);
 
 	req = skcipher_request_alloc(tfm, gfp_flags);
 	if (!req)
@@ -137,28 +144,29 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw,
 		res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
 	skcipher_request_free(req);
 	if (res) {
-		fscrypt_err(inode, "%scryption failed for block %llu: %d",
-			    (rw == FS_DECRYPT ? "De" : "En"), lblk_num, res);
+		fscrypt_err(ci->ci_inode,
+			    "%scryption failed for data unit %llu: %d",
+			    (rw == FS_DECRYPT ? "De" : "En"), index, res);
 		return res;
 	}
 	return 0;
 }
 
 /**
- * fscrypt_encrypt_pagecache_blocks() - Encrypt filesystem blocks from a
- *					pagecache page
- * @page:      The locked pagecache page containing the block(s) to encrypt
- * @len:       Total size of the block(s) to encrypt.  Must be a nonzero
- *		multiple of the filesystem's block size.
- * @offs:      Byte offset within @page of the first block to encrypt.  Must be
- *		a multiple of the filesystem's block size.
- * @gfp_flags: Memory allocation flags.  See details below.
+ * fscrypt_encrypt_pagecache_blocks() - Encrypt data from a pagecache page
+ * @page: the locked pagecache page containing the data to encrypt
+ * @len: size of the data to encrypt, in bytes
+ * @offs: offset within @page of the data to encrypt, in bytes
+ * @gfp_flags: memory allocation flags; see details below
+ *
+ * This allocates a new bounce page and encrypts the given data into it.  The
+ * length and offset of the data must be aligned to the file's crypto data unit
+ * size.  Alignment to the filesystem block size fulfills this requirement, as
+ * the filesystem block size is always a multiple of the data unit size.
  *
- * A new bounce page is allocated, and the specified block(s) are encrypted into
- * it.  In the bounce page, the ciphertext block(s) will be located at the same
- * offsets at which the plaintext block(s) were located in the source page; any
- * other parts of the bounce page will be left uninitialized.  However, normally
- * blocksize == PAGE_SIZE and the whole page is encrypted at once.
+ * In the bounce page, the ciphertext data will be located at the same offset at
+ * which the plaintext data was located in the source page.  Any other parts of
+ * the bounce page will be left uninitialized.
  *
  * This is for use by the filesystem's ->writepages() method.
  *
@@ -176,28 +184,29 @@ struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
 
 {
 	const struct inode *inode = page->mapping->host;
-	const unsigned int blockbits = inode->i_blkbits;
-	const unsigned int blocksize = 1 << blockbits;
+	const struct fscrypt_inode_info *ci = inode->i_crypt_info;
+	const unsigned int du_bits = ci->ci_data_unit_bits;
+	const unsigned int du_size = 1U << du_bits;
 	struct page *ciphertext_page;
-	u64 lblk_num = ((u64)page->index << (PAGE_SHIFT - blockbits)) +
-		       (offs >> blockbits);
+	u64 index = ((u64)page->index << (PAGE_SHIFT - du_bits)) +
+		    (offs >> du_bits);
 	unsigned int i;
 	int err;
 
 	if (WARN_ON_ONCE(!PageLocked(page)))
 		return ERR_PTR(-EINVAL);
 
-	if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, blocksize)))
+	if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size)))
 		return ERR_PTR(-EINVAL);
 
 	ciphertext_page = fscrypt_alloc_bounce_page(gfp_flags);
 	if (!ciphertext_page)
 		return ERR_PTR(-ENOMEM);
 
-	for (i = offs; i < offs + len; i += blocksize, lblk_num++) {
-		err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk_num,
-					  page, ciphertext_page,
-					  blocksize, i, gfp_flags);
+	for (i = offs; i < offs + len; i += du_size, index++) {
+		err = fscrypt_crypt_data_unit(ci, FS_ENCRYPT, index,
+					      page, ciphertext_page,
+					      du_size, i, gfp_flags);
 		if (err) {
 			fscrypt_free_bounce_page(ciphertext_page);
 			return ERR_PTR(err);
@@ -224,30 +233,33 @@ EXPORT_SYMBOL(fscrypt_encrypt_pagecache_blocks);
  * arbitrary page, not necessarily in the original pagecache page.  The @inode
  * and @lblk_num must be specified, as they can't be determined from @page.
  *
+ * This is not compatible with fscrypt_operations::supports_subblock_data_units.
+ *
  * Return: 0 on success; -errno on failure
  */
 int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page,
 				  unsigned int len, unsigned int offs,
 				  u64 lblk_num, gfp_t gfp_flags)
 {
-	return fscrypt_crypt_block(inode, FS_ENCRYPT, lblk_num, page, page,
-				   len, offs, gfp_flags);
+	if (WARN_ON_ONCE(inode->i_sb->s_cop->supports_subblock_data_units))
+		return -EOPNOTSUPP;
+	return fscrypt_crypt_data_unit(inode->i_crypt_info, FS_ENCRYPT,
+				       lblk_num, page, page, len, offs,
+				       gfp_flags);
 }
 EXPORT_SYMBOL(fscrypt_encrypt_block_inplace);
 
 /**
- * fscrypt_decrypt_pagecache_blocks() - Decrypt filesystem blocks in a
- *					pagecache folio
- * @folio:     The locked pagecache folio containing the block(s) to decrypt
- * @len:       Total size of the block(s) to decrypt.  Must be a nonzero
- *		multiple of the filesystem's block size.
- * @offs:      Byte offset within @folio of the first block to decrypt.  Must be
- *		a multiple of the filesystem's block size.
+ * fscrypt_decrypt_pagecache_blocks() - Decrypt data from a pagecache folio
+ * @folio: the pagecache folio containing the data to decrypt
+ * @len: size of the data to decrypt, in bytes
+ * @offs: offset within @folio of the data to decrypt, in bytes
  *
- * The specified block(s) are decrypted in-place within the pagecache folio,
- * which must still be locked and not uptodate.
- *
- * This is for use by the filesystem's ->readahead() method.
+ * Decrypt data that has just been read from an encrypted file.  The data must
+ * be located in a pagecache folio that is still locked and not yet uptodate.
+ * The length and offset of the data must be aligned to the file's crypto data
+ * unit size.  Alignment to the filesystem block size fulfills this requirement,
+ * as the filesystem block size is always a multiple of the data unit size.
  *
  * Return: 0 on success; -errno on failure
  */
@@ -255,25 +267,26 @@ int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len,
 				     size_t offs)
 {
 	const struct inode *inode = folio->mapping->host;
-	const unsigned int blockbits = inode->i_blkbits;
-	const unsigned int blocksize = 1 << blockbits;
-	u64 lblk_num = ((u64)folio->index << (PAGE_SHIFT - blockbits)) +
-		       (offs >> blockbits);
+	const struct fscrypt_inode_info *ci = inode->i_crypt_info;
+	const unsigned int du_bits = ci->ci_data_unit_bits;
+	const unsigned int du_size = 1U << du_bits;
+	u64 index = ((u64)folio->index << (PAGE_SHIFT - du_bits)) +
+		    (offs >> du_bits);
 	size_t i;
 	int err;
 
 	if (WARN_ON_ONCE(!folio_test_locked(folio)))
 		return -EINVAL;
 
-	if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, blocksize)))
+	if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size)))
 		return -EINVAL;
 
-	for (i = offs; i < offs + len; i += blocksize, lblk_num++) {
+	for (i = offs; i < offs + len; i += du_size, index++) {
 		struct page *page = folio_page(folio, i >> PAGE_SHIFT);
 
-		err = fscrypt_crypt_block(inode, FS_DECRYPT, lblk_num, page,
-					  page, blocksize, i & ~PAGE_MASK,
-					  GFP_NOFS);
+		err = fscrypt_crypt_data_unit(ci, FS_DECRYPT, index, page,
+					      page, du_size, i & ~PAGE_MASK,
+					      GFP_NOFS);
 		if (err)
 			return err;
 	}
@@ -295,14 +308,19 @@ EXPORT_SYMBOL(fscrypt_decrypt_pagecache_blocks);
  * arbitrary page, not necessarily in the original pagecache page.  The @inode
  * and @lblk_num must be specified, as they can't be determined from @page.
  *
+ * This is not compatible with fscrypt_operations::supports_subblock_data_units.
+ *
  * Return: 0 on success; -errno on failure
  */
 int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page,
 				  unsigned int len, unsigned int offs,
 				  u64 lblk_num)
 {
-	return fscrypt_crypt_block(inode, FS_DECRYPT, lblk_num, page, page,
-				   len, offs, GFP_NOFS);
+	if (WARN_ON_ONCE(inode->i_sb->s_cop->supports_subblock_data_units))
+		return -EOPNOTSUPP;
+	return fscrypt_crypt_data_unit(inode->i_crypt_info, FS_DECRYPT,
+				       lblk_num, page, page, len, offs,
+				       GFP_NOFS);
 }
 EXPORT_SYMBOL(fscrypt_decrypt_block_inplace);
 
@@ -325,7 +343,7 @@ int fscrypt_initialize(struct super_block *sb)
 		return 0;
 
 	/* No need to allocate a bounce page pool if this FS won't use it. */
-	if (sb->s_cop->flags & FS_CFLG_OWN_PAGES)
+	if (!sb->s_cop->needs_bounce_pages)
 		return 0;
 
 	mutex_lock(&fscrypt_init_mutex);
@@ -391,18 +409,19 @@ static int __init fscrypt_init(void)
 	if (!fscrypt_read_workqueue)
 		goto fail;
 
-	fscrypt_info_cachep = KMEM_CACHE(fscrypt_info, SLAB_RECLAIM_ACCOUNT);
-	if (!fscrypt_info_cachep)
+	fscrypt_inode_info_cachep = KMEM_CACHE(fscrypt_inode_info,
+					       SLAB_RECLAIM_ACCOUNT);
+	if (!fscrypt_inode_info_cachep)
 		goto fail_free_queue;
 
 	err = fscrypt_init_keyring();
 	if (err)
-		goto fail_free_info;
+		goto fail_free_inode_info;
 
 	return 0;
 
-fail_free_info:
-	kmem_cache_destroy(fscrypt_info_cachep);
+fail_free_inode_info:
+	kmem_cache_destroy(fscrypt_inode_info_cachep);
 fail_free_queue:
 	destroy_workqueue(fscrypt_read_workqueue);
 fail:
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 6eae3f12ad50..7b3fc189593a 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -100,7 +100,7 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 {
 	struct skcipher_request *req = NULL;
 	DECLARE_CRYPTO_WAIT(wait);
-	const struct fscrypt_info *ci = inode->i_crypt_info;
+	const struct fscrypt_inode_info *ci = inode->i_crypt_info;
 	struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
 	union fscrypt_iv iv;
 	struct scatterlist sg;
@@ -157,7 +157,7 @@ static int fname_decrypt(const struct inode *inode,
 	struct skcipher_request *req = NULL;
 	DECLARE_CRYPTO_WAIT(wait);
 	struct scatterlist src_sg, dst_sg;
-	const struct fscrypt_info *ci = inode->i_crypt_info;
+	const struct fscrypt_inode_info *ci = inode->i_crypt_info;
 	struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
 	union fscrypt_iv iv;
 	int res;
@@ -568,7 +568,7 @@ EXPORT_SYMBOL_GPL(fscrypt_match_name);
  */
 u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name)
 {
-	const struct fscrypt_info *ci = dir->i_crypt_info;
+	const struct fscrypt_inode_info *ci = dir->i_crypt_info;
 
 	WARN_ON_ONCE(!ci->ci_dirhash_key_initialized);
 
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 2d63da48635a..1892356cf924 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -47,7 +47,8 @@ struct fscrypt_context_v2 {
 	u8 contents_encryption_mode;
 	u8 filenames_encryption_mode;
 	u8 flags;
-	u8 __reserved[4];
+	u8 log2_data_unit_size;
+	u8 __reserved[3];
 	u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
 	u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
 };
@@ -165,6 +166,26 @@ fscrypt_policy_flags(const union fscrypt_policy *policy)
 	BUG();
 }
 
+static inline int
+fscrypt_policy_v2_du_bits(const struct fscrypt_policy_v2 *policy,
+			  const struct inode *inode)
+{
+	return policy->log2_data_unit_size ?: inode->i_blkbits;
+}
+
+static inline int
+fscrypt_policy_du_bits(const union fscrypt_policy *policy,
+		       const struct inode *inode)
+{
+	switch (policy->version) {
+	case FSCRYPT_POLICY_V1:
+		return inode->i_blkbits;
+	case FSCRYPT_POLICY_V2:
+		return fscrypt_policy_v2_du_bits(&policy->v2, inode);
+	}
+	BUG();
+}
+
 /*
  * For encrypted symlinks, the ciphertext length is stored at the beginning
  * of the string in little-endian format.
@@ -189,18 +210,18 @@ struct fscrypt_prepared_key {
 };
 
 /*
- * fscrypt_info - the "encryption key" for an inode
+ * fscrypt_inode_info - the "encryption key" for an inode
  *
  * When an encrypted file's key is made available, an instance of this struct is
  * allocated and stored in ->i_crypt_info.  Once created, it remains until the
  * inode is evicted.
  */
-struct fscrypt_info {
+struct fscrypt_inode_info {
 
 	/* The key in a form prepared for actual encryption/decryption */
 	struct fscrypt_prepared_key ci_enc_key;
 
-	/* True if ci_enc_key should be freed when this fscrypt_info is freed */
+	/* True if ci_enc_key should be freed when this struct is freed */
 	bool ci_owns_key;
 
 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
@@ -212,6 +233,16 @@ struct fscrypt_info {
 #endif
 
 	/*
+	 * log2 of the data unit size (granularity of contents encryption) of
+	 * this file.  This is computable from ci_policy and ci_inode but is
+	 * cached here for efficiency.  Only used for regular files.
+	 */
+	u8 ci_data_unit_bits;
+
+	/* Cached value: log2 of number of data units per FS block */
+	u8 ci_data_units_per_block_bits;
+
+	/*
 	 * Encryption mode used for this inode.  It corresponds to either the
 	 * contents or filenames encryption mode, depending on the inode type.
 	 */
@@ -263,12 +294,13 @@ typedef enum {
 } fscrypt_direction_t;
 
 /* crypto.c */
-extern struct kmem_cache *fscrypt_info_cachep;
+extern struct kmem_cache *fscrypt_inode_info_cachep;
 int fscrypt_initialize(struct super_block *sb);
-int fscrypt_crypt_block(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);
+int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
+			    fscrypt_direction_t rw, u64 index,
+			    struct page *src_page, struct page *dest_page,
+			    unsigned int len, unsigned int offs,
+			    gfp_t gfp_flags);
 struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags);
 
 void __printf(3, 4) __cold
@@ -283,8 +315,8 @@ fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...);
 
 union fscrypt_iv {
 	struct {
-		/* logical block number within the file */
-		__le64 lblk_num;
+		/* zero-based index of data unit within the file */
+		__le64 index;
 
 		/* per-file nonce; only set in DIRECT_KEY mode */
 		u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
@@ -293,8 +325,18 @@ union fscrypt_iv {
 	__le64 dun[FSCRYPT_MAX_IV_SIZE / sizeof(__le64)];
 };
 
-void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
-			 const struct fscrypt_info *ci);
+void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index,
+			 const struct fscrypt_inode_info *ci);
+
+/*
+ * Return the number of bits used by the maximum file data unit index that is
+ * possible on the given filesystem, using the given log2 data unit size.
+ */
+static inline int
+fscrypt_max_file_dun_bits(const struct super_block *sb, int du_bits)
+{
+	return fls64(sb->s_maxbytes - 1) - du_bits;
+}
 
 /* fname.c */
 bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
@@ -332,17 +374,17 @@ void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf);
 
 /* inline_crypt.c */
 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
-int fscrypt_select_encryption_impl(struct fscrypt_info *ci);
+int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci);
 
 static inline bool
-fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
+fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci)
 {
 	return ci->ci_inlinecrypt;
 }
 
 int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
 				     const u8 *raw_key,
-				     const struct fscrypt_info *ci);
+				     const struct fscrypt_inode_info *ci);
 
 void fscrypt_destroy_inline_crypt_key(struct super_block *sb,
 				      struct fscrypt_prepared_key *prep_key);
@@ -353,7 +395,7 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb,
  */
 static inline bool
 fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
-			const struct fscrypt_info *ci)
+			const struct fscrypt_inode_info *ci)
 {
 	/*
 	 * The two smp_load_acquire()'s here pair with the smp_store_release()'s
@@ -370,13 +412,13 @@ fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
 
 #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
 
-static inline int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
+static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci)
 {
 	return 0;
 }
 
 static inline bool
-fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
+fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci)
 {
 	return false;
 }
@@ -384,7 +426,7 @@ fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
 static inline int
 fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
 				 const u8 *raw_key,
-				 const struct fscrypt_info *ci)
+				 const struct fscrypt_inode_info *ci)
 {
 	WARN_ON_ONCE(1);
 	return -EOPNOTSUPP;
@@ -398,7 +440,7 @@ fscrypt_destroy_inline_crypt_key(struct super_block *sb,
 
 static inline bool
 fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
-			const struct fscrypt_info *ci)
+			const struct fscrypt_inode_info *ci)
 {
 	return smp_load_acquire(&prep_key->tfm) != NULL;
 }
@@ -433,8 +475,28 @@ struct fscrypt_master_key_secret {
  * fscrypt_master_key - an in-use master key
  *
  * This represents a master encryption key which has been added to the
- * filesystem and can be used to "unlock" the encrypted files which were
- * encrypted with it.
+ * filesystem.  There are three high-level states that a key can be in:
+ *
+ * FSCRYPT_KEY_STATUS_PRESENT
+ *	Key is fully usable; it can be used to unlock inodes that are encrypted
+ *	with it (this includes being able to create new inodes).  ->mk_present
+ *	indicates whether the key is in this state.  ->mk_secret exists, the key
+ *	is in the keyring, and ->mk_active_refs > 0 due to ->mk_present.
+ *
+ * FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED
+ *	Removal of this key has been initiated, but some inodes that were
+ *	unlocked with it are still in-use.  Like ABSENT, ->mk_secret is wiped,
+ *	and the key can no longer be used to unlock inodes.  Unlike ABSENT, the
+ *	key is still in the keyring; ->mk_decrypted_inodes is nonempty; and
+ *	->mk_active_refs > 0, being equal to the size of ->mk_decrypted_inodes.
+ *
+ *	This state transitions to ABSENT if ->mk_decrypted_inodes becomes empty,
+ *	or to PRESENT if FS_IOC_ADD_ENCRYPTION_KEY is called again for this key.
+ *
+ * FSCRYPT_KEY_STATUS_ABSENT
+ *	Key is fully removed.  The key is no longer in the keyring,
+ *	->mk_decrypted_inodes is empty, ->mk_active_refs == 0, ->mk_secret is
+ *	wiped, and the key can no longer be used to unlock inodes.
  */
 struct fscrypt_master_key {
 
@@ -444,7 +506,7 @@ struct fscrypt_master_key {
 	 */
 	struct hlist_node			mk_node;
 
-	/* Semaphore that protects ->mk_secret and ->mk_users */
+	/* Semaphore that protects ->mk_secret, ->mk_users, and ->mk_present */
 	struct rw_semaphore			mk_sem;
 
 	/*
@@ -454,8 +516,8 @@ struct fscrypt_master_key {
 	 * ->mk_direct_keys) that have been prepared continue to exist.
 	 * A structural ref only guarantees that the struct continues to exist.
 	 *
-	 * There is one active ref associated with ->mk_secret being present,
-	 * and one active ref for each inode in ->mk_decrypted_inodes.
+	 * There is one active ref associated with ->mk_present being true, and
+	 * one active ref for each inode in ->mk_decrypted_inodes.
 	 *
 	 * There is one structural ref associated with the active refcount being
 	 * nonzero.  Finding a key in the keyring also takes a structural ref,
@@ -467,17 +529,10 @@ struct fscrypt_master_key {
 	struct rcu_head				mk_rcu_head;
 
 	/*
-	 * The secret key material.  After FS_IOC_REMOVE_ENCRYPTION_KEY is
-	 * executed, this is wiped and no new inodes can be unlocked with this
-	 * key; however, there may still be inodes in ->mk_decrypted_inodes
-	 * which could not be evicted.  As long as some inodes still remain,
-	 * FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or
-	 * FS_IOC_ADD_ENCRYPTION_KEY can add the secret again.
+	 * The secret key material.  Wiped as soon as it is no longer needed;
+	 * for details, see the fscrypt_master_key struct comment.
 	 *
-	 * While ->mk_secret is present, one ref in ->mk_active_refs is held.
-	 *
-	 * Locking: protected by ->mk_sem.  The manipulation of ->mk_active_refs
-	 *	    associated with this field is protected by ->mk_sem as well.
+	 * Locking: protected by ->mk_sem.
 	 */
 	struct fscrypt_master_key_secret	mk_secret;
 
@@ -500,7 +555,7 @@ struct fscrypt_master_key {
 	 *
 	 * Locking: protected by ->mk_sem.  (We don't just rely on the keyrings
 	 * subsystem semaphore ->mk_users->sem, as we need support for atomic
-	 * search+insert along with proper synchronization with ->mk_secret.)
+	 * search+insert along with proper synchronization with other fields.)
 	 */
 	struct key		*mk_users;
 
@@ -523,20 +578,17 @@ struct fscrypt_master_key {
 	siphash_key_t		mk_ino_hash_key;
 	bool			mk_ino_hash_key_initialized;
 
-} __randomize_layout;
-
-static inline bool
-is_master_key_secret_present(const struct fscrypt_master_key_secret *secret)
-{
 	/*
-	 * The READ_ONCE() is only necessary for fscrypt_drop_inode().
-	 * fscrypt_drop_inode() runs in atomic context, so it can't take the key
-	 * semaphore and thus 'secret' can change concurrently which would be a
-	 * data race.  But fscrypt_drop_inode() only need to know whether the
-	 * secret *was* present at the time of check, so READ_ONCE() suffices.
+	 * Whether this key is in the "present" state, i.e. fully usable.  For
+	 * details, see the fscrypt_master_key struct comment.
+	 *
+	 * Locking: protected by ->mk_sem, but can be read locklessly using
+	 * READ_ONCE().  Writers must use WRITE_ONCE() when concurrent readers
+	 * are possible.
 	 */
-	return READ_ONCE(secret->size) != 0;
-}
+	bool			mk_present;
+
+} __randomize_layout;
 
 static inline const char *master_key_spec_type(
 				const struct fscrypt_key_specifier *spec)
@@ -598,17 +650,18 @@ struct fscrypt_mode {
 extern struct fscrypt_mode fscrypt_modes[];
 
 int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key,
-			const u8 *raw_key, const struct fscrypt_info *ci);
+			const u8 *raw_key, const struct fscrypt_inode_info *ci);
 
 void fscrypt_destroy_prepared_key(struct super_block *sb,
 				  struct fscrypt_prepared_key *prep_key);
 
-int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key);
+int fscrypt_set_per_file_enc_key(struct fscrypt_inode_info *ci,
+				 const u8 *raw_key);
 
-int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
+int fscrypt_derive_dirhash_key(struct fscrypt_inode_info *ci,
 			       const struct fscrypt_master_key *mk);
 
-void fscrypt_hash_inode_number(struct fscrypt_info *ci,
+void fscrypt_hash_inode_number(struct fscrypt_inode_info *ci,
 			       const struct fscrypt_master_key *mk);
 
 int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported);
@@ -643,10 +696,11 @@ static inline int fscrypt_require_key(struct inode *inode)
 
 void fscrypt_put_direct_key(struct fscrypt_direct_key *dk);
 
-int fscrypt_setup_v1_file_key(struct fscrypt_info *ci,
+int fscrypt_setup_v1_file_key(struct fscrypt_inode_info *ci,
 			      const u8 *raw_master_key);
 
-int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci);
+int fscrypt_setup_v1_file_key_via_subscribed_keyrings(
+				struct fscrypt_inode_info *ci);
 
 /* policy.c */
 
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index 6238dbcadcad..52504dd478d3 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -169,7 +169,7 @@ EXPORT_SYMBOL_GPL(__fscrypt_prepare_setattr);
 int fscrypt_prepare_setflags(struct inode *inode,
 			     unsigned int oldflags, unsigned int flags)
 {
-	struct fscrypt_info *ci;
+	struct fscrypt_inode_info *ci;
 	struct fscrypt_master_key *mk;
 	int err;
 
@@ -187,7 +187,7 @@ int fscrypt_prepare_setflags(struct inode *inode,
 			return -EINVAL;
 		mk = ci->ci_master_key;
 		down_read(&mk->mk_sem);
-		if (is_master_key_secret_present(&mk->mk_secret))
+		if (mk->mk_present)
 			err = fscrypt_derive_dirhash_key(ci, mk);
 		else
 			err = -ENOKEY;
diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c
index 8bfb3ce86476..b4002aea7cdb 100644
--- a/fs/crypto/inline_crypt.c
+++ b/fs/crypto/inline_crypt.c
@@ -39,11 +39,11 @@ static struct block_device **fscrypt_get_devices(struct super_block *sb,
 	return devs;
 }
 
-static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci)
+static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_inode_info *ci)
 {
-	struct super_block *sb = ci->ci_inode->i_sb;
+	const struct super_block *sb = ci->ci_inode->i_sb;
 	unsigned int flags = fscrypt_policy_flags(&ci->ci_policy);
-	int ino_bits = 64, lblk_bits = 64;
+	int dun_bits;
 
 	if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY)
 		return offsetofend(union fscrypt_iv, nonce);
@@ -54,10 +54,9 @@ static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci)
 	if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)
 		return sizeof(__le32);
 
-	/* Default case: IVs are just the file logical block number */
-	if (sb->s_cop->get_ino_and_lblk_bits)
-		sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits);
-	return DIV_ROUND_UP(lblk_bits, 8);
+	/* Default case: IVs are just the file data unit index */
+	dun_bits = fscrypt_max_file_dun_bits(sb, ci->ci_data_unit_bits);
+	return DIV_ROUND_UP(dun_bits, 8);
 }
 
 /*
@@ -90,7 +89,7 @@ static void fscrypt_log_blk_crypto_impl(struct fscrypt_mode *mode,
 }
 
 /* Enable inline encryption for this file if supported. */
-int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
+int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci)
 {
 	const struct inode *inode = ci->ci_inode;
 	struct super_block *sb = inode->i_sb;
@@ -129,7 +128,7 @@ int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
 	 * crypto configuration that the file would use.
 	 */
 	crypto_cfg.crypto_mode = ci->ci_mode->blk_crypto_mode;
-	crypto_cfg.data_unit_size = sb->s_blocksize;
+	crypto_cfg.data_unit_size = 1U << ci->ci_data_unit_bits;
 	crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci);
 
 	devs = fscrypt_get_devices(sb, &num_devs);
@@ -152,7 +151,7 @@ out_free_devs:
 
 int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
 				     const u8 *raw_key,
-				     const struct fscrypt_info *ci)
+				     const struct fscrypt_inode_info *ci)
 {
 	const struct inode *inode = ci->ci_inode;
 	struct super_block *sb = inode->i_sb;
@@ -168,7 +167,8 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
 		return -ENOMEM;
 
 	err = blk_crypto_init_key(blk_key, raw_key, crypto_mode,
-				  fscrypt_get_dun_bytes(ci), sb->s_blocksize);
+				  fscrypt_get_dun_bytes(ci),
+				  1U << ci->ci_data_unit_bits);
 	if (err) {
 		fscrypt_err(inode, "error %d initializing blk-crypto key", err);
 		goto fail;
@@ -232,13 +232,15 @@ bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode)
 }
 EXPORT_SYMBOL_GPL(__fscrypt_inode_uses_inline_crypto);
 
-static void fscrypt_generate_dun(const struct fscrypt_info *ci, u64 lblk_num,
+static void fscrypt_generate_dun(const struct fscrypt_inode_info *ci,
+				 u64 lblk_num,
 				 u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE])
 {
+	u64 index = lblk_num << ci->ci_data_units_per_block_bits;
 	union fscrypt_iv iv;
 	int i;
 
-	fscrypt_generate_iv(&iv, lblk_num, ci);
+	fscrypt_generate_iv(&iv, index, ci);
 
 	BUILD_BUG_ON(FSCRYPT_MAX_IV_SIZE > BLK_CRYPTO_MAX_IV_SIZE);
 	memset(dun, 0, BLK_CRYPTO_MAX_IV_SIZE);
@@ -265,7 +267,7 @@ static void fscrypt_generate_dun(const struct fscrypt_info *ci, u64 lblk_num,
 void fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode,
 			       u64 first_lblk, gfp_t gfp_mask)
 {
-	const struct fscrypt_info *ci;
+	const struct fscrypt_inode_info *ci;
 	u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
 
 	if (!fscrypt_inode_uses_inline_crypto(inode))
@@ -456,7 +458,7 @@ EXPORT_SYMBOL_GPL(fscrypt_dio_supported);
  */
 u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks)
 {
-	const struct fscrypt_info *ci;
+	const struct fscrypt_inode_info *ci;
 	u32 dun;
 
 	if (!fscrypt_inode_uses_inline_crypto(inode))
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 7cbb1fd872ac..f34a9b0b9e92 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -99,10 +99,10 @@ void fscrypt_put_master_key_activeref(struct super_block *sb,
 	spin_unlock(&sb->s_master_keys->lock);
 
 	/*
-	 * ->mk_active_refs == 0 implies that ->mk_secret is not present and
-	 * that ->mk_decrypted_inodes is empty.
+	 * ->mk_active_refs == 0 implies that ->mk_present is false and
+	 * ->mk_decrypted_inodes is empty.
 	 */
-	WARN_ON_ONCE(is_master_key_secret_present(&mk->mk_secret));
+	WARN_ON_ONCE(mk->mk_present);
 	WARN_ON_ONCE(!list_empty(&mk->mk_decrypted_inodes));
 
 	for (i = 0; i <= FSCRYPT_MODE_MAX; i++) {
@@ -121,6 +121,18 @@ void fscrypt_put_master_key_activeref(struct super_block *sb,
 	fscrypt_put_master_key(mk);
 }
 
+/*
+ * This transitions the key state from present to incompletely removed, and then
+ * potentially to absent (depending on whether inodes remain).
+ */
+static void fscrypt_initiate_key_removal(struct super_block *sb,
+					 struct fscrypt_master_key *mk)
+{
+	WRITE_ONCE(mk->mk_present, false);
+	wipe_master_key_secret(&mk->mk_secret);
+	fscrypt_put_master_key_activeref(sb, mk);
+}
+
 static inline bool valid_key_spec(const struct fscrypt_key_specifier *spec)
 {
 	if (spec->__reserved)
@@ -234,14 +246,13 @@ void fscrypt_destroy_keyring(struct super_block *sb)
 			 * evicted, every key remaining in the keyring should
 			 * have an empty inode list, and should only still be in
 			 * the keyring due to the single active ref associated
-			 * with ->mk_secret.  There should be no structural refs
-			 * beyond the one associated with the active ref.
+			 * with ->mk_present.  There should be no structural
+			 * refs beyond the one associated with the active ref.
 			 */
 			WARN_ON_ONCE(refcount_read(&mk->mk_active_refs) != 1);
 			WARN_ON_ONCE(refcount_read(&mk->mk_struct_refs) != 1);
-			WARN_ON_ONCE(!is_master_key_secret_present(&mk->mk_secret));
-			wipe_master_key_secret(&mk->mk_secret);
-			fscrypt_put_master_key_activeref(sb, mk);
+			WARN_ON_ONCE(!mk->mk_present);
+			fscrypt_initiate_key_removal(sb, mk);
 		}
 	}
 	kfree_sensitive(keyring);
@@ -439,7 +450,8 @@ static int add_new_master_key(struct super_block *sb,
 	}
 
 	move_master_key_secret(&mk->mk_secret, secret);
-	refcount_set(&mk->mk_active_refs, 1); /* ->mk_secret is present */
+	mk->mk_present = true;
+	refcount_set(&mk->mk_active_refs, 1); /* ->mk_present is true */
 
 	spin_lock(&keyring->lock);
 	hlist_add_head_rcu(&mk->mk_node,
@@ -478,11 +490,18 @@ static int add_existing_master_key(struct fscrypt_master_key *mk,
 			return err;
 	}
 
-	/* Re-add the secret if needed. */
-	if (!is_master_key_secret_present(&mk->mk_secret)) {
-		if (!refcount_inc_not_zero(&mk->mk_active_refs))
+	/* If the key is incompletely removed, make it present again. */
+	if (!mk->mk_present) {
+		if (!refcount_inc_not_zero(&mk->mk_active_refs)) {
+			/*
+			 * Raced with the last active ref being dropped, so the
+			 * key has become, or is about to become, "absent".
+			 * Therefore, we need to allocate a new key struct.
+			 */
 			return KEY_DEAD;
+		}
 		move_master_key_secret(&mk->mk_secret, secret);
+		WRITE_ONCE(mk->mk_present, true);
 	}
 
 	return 0;
@@ -506,8 +525,8 @@ static int do_add_master_key(struct super_block *sb,
 			err = add_new_master_key(sb, secret, mk_spec);
 	} else {
 		/*
-		 * Found the key in ->s_master_keys.  Re-add the secret if
-		 * needed, and add the user to ->mk_users if needed.
+		 * Found the key in ->s_master_keys.  Add the user to ->mk_users
+		 * if needed, and make the key "present" again if possible.
 		 */
 		down_write(&mk->mk_sem);
 		err = add_existing_master_key(mk, secret);
@@ -867,7 +886,7 @@ static void shrink_dcache_inode(struct inode *inode)
 
 static void evict_dentries_for_decrypted_inodes(struct fscrypt_master_key *mk)
 {
-	struct fscrypt_info *ci;
+	struct fscrypt_inode_info *ci;
 	struct inode *inode;
 	struct inode *toput_inode = NULL;
 
@@ -917,7 +936,7 @@ static int check_for_busy_inodes(struct super_block *sb,
 		/* select an example file to show for debugging purposes */
 		struct inode *inode =
 			list_first_entry(&mk->mk_decrypted_inodes,
-					 struct fscrypt_info,
+					 struct fscrypt_inode_info,
 					 ci_master_key_link)->ci_inode;
 		ino = inode->i_ino;
 	}
@@ -989,9 +1008,8 @@ static int try_to_lock_encrypted_files(struct super_block *sb,
  *
  * If all inodes were evicted, then we unlink the fscrypt_master_key from the
  * keyring.  Otherwise it remains in the keyring in the "incompletely removed"
- * state (without the actual secret key) where it tracks the list of remaining
- * inodes.  Userspace can execute the ioctl again later to retry eviction, or
- * alternatively can re-add the secret key again.
+ * state where it tracks the list of remaining inodes.  Userspace can execute
+ * the ioctl again later to retry eviction, or alternatively can re-add the key.
  *
  * For more details, see the "Removing keys" section of
  * Documentation/filesystems/fscrypt.rst.
@@ -1053,11 +1071,10 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
 		}
 	}
 
-	/* No user claims remaining.  Go ahead and wipe the secret. */
+	/* No user claims remaining.  Initiate removal of the key. */
 	err = -ENOKEY;
-	if (is_master_key_secret_present(&mk->mk_secret)) {
-		wipe_master_key_secret(&mk->mk_secret);
-		fscrypt_put_master_key_activeref(sb, mk);
+	if (mk->mk_present) {
+		fscrypt_initiate_key_removal(sb, mk);
 		err = 0;
 	}
 	inodes_remain = refcount_read(&mk->mk_active_refs) > 0;
@@ -1074,9 +1091,9 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
 	}
 	/*
 	 * We return 0 if we successfully did something: removed a claim to the
-	 * key, wiped the secret, or tried locking the files again.  Users need
-	 * to check the informational status flags if they care whether the key
-	 * has been fully removed including all files locked.
+	 * key, initiated removal of the key, or tried locking the files again.
+	 * Users need to check the informational status flags if they care
+	 * whether the key has been fully removed including all files locked.
 	 */
 out_put_key:
 	fscrypt_put_master_key(mk);
@@ -1103,12 +1120,11 @@ EXPORT_SYMBOL_GPL(fscrypt_ioctl_remove_key_all_users);
  * Retrieve the status of an fscrypt master encryption key.
  *
  * We set ->status to indicate whether the key is absent, present, or
- * incompletely removed.  "Incompletely removed" means that the master key
- * secret has been removed, but some files which had been unlocked with it are
- * still in use.  This field allows applications to easily determine the state
- * of an encrypted directory without using a hack such as trying to open a
- * regular file in it (which can confuse the "incompletely removed" state with
- * absent or present).
+ * incompletely removed.  (For an explanation of what these statuses mean and
+ * how they are represented internally, see struct fscrypt_master_key.)  This
+ * field allows applications to easily determine the status of an encrypted
+ * directory without using a hack such as trying to open a regular file in it
+ * (which can confuse the "incompletely removed" status with absent or present).
  *
  * In addition, for v2 policy keys we allow applications to determine, via
  * ->status_flags and ->user_count, whether the key has been added by the
@@ -1150,7 +1166,7 @@ int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg)
 	}
 	down_read(&mk->mk_sem);
 
-	if (!is_master_key_secret_present(&mk->mk_secret)) {
+	if (!mk->mk_present) {
 		arg.status = refcount_read(&mk->mk_active_refs) > 0 ?
 			FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED :
 			FSCRYPT_KEY_STATUS_ABSENT /* raced with full removal */;
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index 361f41ef46c7..d71f7c799e79 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -148,7 +148,7 @@ err_free_tfm:
  * and IV generation method (@ci->ci_policy.flags).
  */
 int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key,
-			const u8 *raw_key, const struct fscrypt_info *ci)
+			const u8 *raw_key, const struct fscrypt_inode_info *ci)
 {
 	struct crypto_skcipher *tfm;
 
@@ -178,13 +178,14 @@ void fscrypt_destroy_prepared_key(struct super_block *sb,
 }
 
 /* Given a per-file encryption key, set up the file's crypto transform object */
-int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key)
+int fscrypt_set_per_file_enc_key(struct fscrypt_inode_info *ci,
+				 const u8 *raw_key)
 {
 	ci->ci_owns_key = true;
 	return fscrypt_prepare_key(&ci->ci_enc_key, raw_key, ci);
 }
 
-static int setup_per_mode_enc_key(struct fscrypt_info *ci,
+static int setup_per_mode_enc_key(struct fscrypt_inode_info *ci,
 				  struct fscrypt_master_key *mk,
 				  struct fscrypt_prepared_key *keys,
 				  u8 hkdf_context, bool include_fs_uuid)
@@ -265,7 +266,7 @@ static int fscrypt_derive_siphash_key(const struct fscrypt_master_key *mk,
 	return 0;
 }
 
-int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
+int fscrypt_derive_dirhash_key(struct fscrypt_inode_info *ci,
 			       const struct fscrypt_master_key *mk)
 {
 	int err;
@@ -279,7 +280,7 @@ int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
 	return 0;
 }
 
-void fscrypt_hash_inode_number(struct fscrypt_info *ci,
+void fscrypt_hash_inode_number(struct fscrypt_inode_info *ci,
 			       const struct fscrypt_master_key *mk)
 {
 	WARN_ON_ONCE(ci->ci_inode->i_ino == 0);
@@ -289,7 +290,7 @@ void fscrypt_hash_inode_number(struct fscrypt_info *ci,
 					      &mk->mk_ino_hash_key);
 }
 
-static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci,
+static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_inode_info *ci,
 					    struct fscrypt_master_key *mk)
 {
 	int err;
@@ -329,7 +330,7 @@ unlock:
 	return 0;
 }
 
-static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci,
+static int fscrypt_setup_v2_file_key(struct fscrypt_inode_info *ci,
 				     struct fscrypt_master_key *mk,
 				     bool need_dirhash_key)
 {
@@ -404,7 +405,7 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci,
  * still allow 512-bit master keys if the user chooses to use them, though.)
  */
 static bool fscrypt_valid_master_key_size(const struct fscrypt_master_key *mk,
-					  const struct fscrypt_info *ci)
+					  const struct fscrypt_inode_info *ci)
 {
 	unsigned int min_keysize;
 
@@ -430,11 +431,12 @@ static bool fscrypt_valid_master_key_size(const struct fscrypt_master_key *mk,
  *
  * If the master key is found in the filesystem-level keyring, then it is
  * returned in *mk_ret with its semaphore read-locked.  This is needed to ensure
- * that only one task links the fscrypt_info into ->mk_decrypted_inodes (as
- * multiple tasks may race to create an fscrypt_info for the same inode), and to
- * synchronize the master key being removed with a new inode starting to use it.
+ * that only one task links the fscrypt_inode_info into ->mk_decrypted_inodes
+ * (as multiple tasks may race to create an fscrypt_inode_info for the same
+ * inode), and to synchronize the master key being removed with a new inode
+ * starting to use it.
  */
-static int setup_file_encryption_key(struct fscrypt_info *ci,
+static int setup_file_encryption_key(struct fscrypt_inode_info *ci,
 				     bool need_dirhash_key,
 				     struct fscrypt_master_key **mk_ret)
 {
@@ -484,8 +486,8 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
 	}
 	down_read(&mk->mk_sem);
 
-	/* Has the secret been removed (via FS_IOC_REMOVE_ENCRYPTION_KEY)? */
-	if (!is_master_key_secret_present(&mk->mk_secret)) {
+	if (!mk->mk_present) {
+		/* FS_IOC_REMOVE_ENCRYPTION_KEY has been executed on this key */
 		err = -ENOKEY;
 		goto out_release_key;
 	}
@@ -519,7 +521,7 @@ out_release_key:
 	return err;
 }
 
-static void put_crypt_info(struct fscrypt_info *ci)
+static void put_crypt_info(struct fscrypt_inode_info *ci)
 {
 	struct fscrypt_master_key *mk;
 
@@ -537,8 +539,8 @@ static void put_crypt_info(struct fscrypt_info *ci)
 		/*
 		 * Remove this inode from the list of inodes that were unlocked
 		 * with the master key.  In addition, if we're removing the last
-		 * inode from a master key struct that already had its secret
-		 * removed, then complete the full removal of the struct.
+		 * inode from an incompletely removed key, then complete the
+		 * full removal of the key.
 		 */
 		spin_lock(&mk->mk_decrypted_inodes_lock);
 		list_del(&ci->ci_master_key_link);
@@ -546,7 +548,7 @@ static void put_crypt_info(struct fscrypt_info *ci)
 		fscrypt_put_master_key_activeref(ci->ci_inode->i_sb, mk);
 	}
 	memzero_explicit(ci, sizeof(*ci));
-	kmem_cache_free(fscrypt_info_cachep, ci);
+	kmem_cache_free(fscrypt_inode_info_cachep, ci);
 }
 
 static int
@@ -555,7 +557,7 @@ fscrypt_setup_encryption_info(struct inode *inode,
 			      const u8 nonce[FSCRYPT_FILE_NONCE_SIZE],
 			      bool need_dirhash_key)
 {
-	struct fscrypt_info *crypt_info;
+	struct fscrypt_inode_info *crypt_info;
 	struct fscrypt_mode *mode;
 	struct fscrypt_master_key *mk = NULL;
 	int res;
@@ -564,7 +566,7 @@ fscrypt_setup_encryption_info(struct inode *inode,
 	if (res)
 		return res;
 
-	crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_KERNEL);
+	crypt_info = kmem_cache_zalloc(fscrypt_inode_info_cachep, GFP_KERNEL);
 	if (!crypt_info)
 		return -ENOMEM;
 
@@ -580,6 +582,11 @@ fscrypt_setup_encryption_info(struct inode *inode,
 	WARN_ON_ONCE(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
 	crypt_info->ci_mode = mode;
 
+	crypt_info->ci_data_unit_bits =
+		fscrypt_policy_du_bits(&crypt_info->ci_policy, inode);
+	crypt_info->ci_data_units_per_block_bits =
+		inode->i_blkbits - crypt_info->ci_data_unit_bits;
+
 	res = setup_file_encryption_key(crypt_info, need_dirhash_key, &mk);
 	if (res)
 		goto out;
@@ -587,8 +594,8 @@ fscrypt_setup_encryption_info(struct inode *inode,
 	/*
 	 * For existing inodes, multiple tasks may race to set ->i_crypt_info.
 	 * So use cmpxchg_release().  This pairs with the smp_load_acquire() in
-	 * fscrypt_get_info().  I.e., here we publish ->i_crypt_info with a
-	 * RELEASE barrier so that other tasks can ACQUIRE it.
+	 * fscrypt_get_inode_info().  I.e., here we publish ->i_crypt_info with
+	 * a RELEASE barrier so that other tasks can ACQUIRE it.
 	 */
 	if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL) {
 		/*
@@ -735,8 +742,8 @@ EXPORT_SYMBOL_GPL(fscrypt_prepare_new_inode);
  * fscrypt_put_encryption_info() - free most of an inode's fscrypt data
  * @inode: an inode being evicted
  *
- * Free the inode's fscrypt_info.  Filesystems must call this when the inode is
- * being evicted.  An RCU grace period need not have elapsed yet.
+ * Free the inode's fscrypt_inode_info.  Filesystems must call this when the
+ * inode is being evicted.  An RCU grace period need not have elapsed yet.
  */
 void fscrypt_put_encryption_info(struct inode *inode)
 {
@@ -773,7 +780,7 @@ EXPORT_SYMBOL(fscrypt_free_inode);
  */
 int fscrypt_drop_inode(struct inode *inode)
 {
-	const struct fscrypt_info *ci = fscrypt_get_info(inode);
+	const struct fscrypt_inode_info *ci = fscrypt_get_inode_info(inode);
 
 	/*
 	 * If ci is NULL, then the inode doesn't have an encryption key set up
@@ -794,13 +801,14 @@ int fscrypt_drop_inode(struct inode *inode)
 		return 0;
 
 	/*
-	 * Note: since we aren't holding the key semaphore, the result here can
+	 * We can't take ->mk_sem here, since this runs in atomic context.
+	 * Therefore, ->mk_present can change concurrently, and our result may
 	 * immediately become outdated.  But there's no correctness problem with
 	 * unnecessarily evicting.  Nor is there a correctness problem with not
 	 * evicting while iput() is racing with the key being removed, since
 	 * then the thread removing the key will either evict the inode itself
 	 * or will correctly detect that it wasn't evicted due to the race.
 	 */
-	return !is_master_key_secret_present(&ci->ci_master_key->mk_secret);
+	return !READ_ONCE(ci->ci_master_key->mk_present);
 }
 EXPORT_SYMBOL_GPL(fscrypt_drop_inode);
diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c
index 75dabd9b27f9..a10710bc8123 100644
--- a/fs/crypto/keysetup_v1.c
+++ b/fs/crypto/keysetup_v1.c
@@ -178,7 +178,8 @@ void fscrypt_put_direct_key(struct fscrypt_direct_key *dk)
  */
 static struct fscrypt_direct_key *
 find_or_insert_direct_key(struct fscrypt_direct_key *to_insert,
-			  const u8 *raw_key, const struct fscrypt_info *ci)
+			  const u8 *raw_key,
+			  const struct fscrypt_inode_info *ci)
 {
 	unsigned long hash_key;
 	struct fscrypt_direct_key *dk;
@@ -218,7 +219,7 @@ find_or_insert_direct_key(struct fscrypt_direct_key *to_insert,
 
 /* Prepare to encrypt directly using the master key in the given mode */
 static struct fscrypt_direct_key *
-fscrypt_get_direct_key(const struct fscrypt_info *ci, const u8 *raw_key)
+fscrypt_get_direct_key(const struct fscrypt_inode_info *ci, const u8 *raw_key)
 {
 	struct fscrypt_direct_key *dk;
 	int err;
@@ -250,7 +251,7 @@ err_free_dk:
 }
 
 /* v1 policy, DIRECT_KEY: use the master key directly */
-static int setup_v1_file_key_direct(struct fscrypt_info *ci,
+static int setup_v1_file_key_direct(struct fscrypt_inode_info *ci,
 				    const u8 *raw_master_key)
 {
 	struct fscrypt_direct_key *dk;
@@ -264,7 +265,7 @@ static int setup_v1_file_key_direct(struct fscrypt_info *ci,
 }
 
 /* v1 policy, !DIRECT_KEY: derive the file's encryption key */
-static int setup_v1_file_key_derived(struct fscrypt_info *ci,
+static int setup_v1_file_key_derived(struct fscrypt_inode_info *ci,
 				     const u8 *raw_master_key)
 {
 	u8 *derived_key;
@@ -289,7 +290,8 @@ out:
 	return err;
 }
 
-int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key)
+int fscrypt_setup_v1_file_key(struct fscrypt_inode_info *ci,
+			      const u8 *raw_master_key)
 {
 	if (ci->ci_policy.v1.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY)
 		return setup_v1_file_key_direct(ci, raw_master_key);
@@ -297,8 +299,10 @@ int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key)
 		return setup_v1_file_key_derived(ci, raw_master_key);
 }
 
-int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
+int
+fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_inode_info *ci)
 {
+	const struct super_block *sb = ci->ci_inode->i_sb;
 	struct key *key;
 	const struct fscrypt_key *payload;
 	int err;
@@ -306,8 +310,8 @@ int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
 	key = find_and_lock_process_key(FSCRYPT_KEY_DESC_PREFIX,
 					ci->ci_policy.v1.master_key_descriptor,
 					ci->ci_mode->keysize, &payload);
-	if (key == ERR_PTR(-ENOKEY) && ci->ci_inode->i_sb->s_cop->key_prefix) {
-		key = find_and_lock_process_key(ci->ci_inode->i_sb->s_cop->key_prefix,
+	if (key == ERR_PTR(-ENOKEY) && sb->s_cop->legacy_key_prefix) {
+		key = find_and_lock_process_key(sb->s_cop->legacy_key_prefix,
 						ci->ci_policy.v1.master_key_descriptor,
 						ci->ci_mode->keysize, &payload);
 	}
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index f4456ecb3f87..701259991277 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -118,12 +118,11 @@ static bool supported_direct_key_modes(const struct inode *inode,
 }
 
 static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy,
-					 const struct inode *inode,
-					 const char *type,
-					 int max_ino_bits, int max_lblk_bits)
+					 const struct inode *inode)
 {
+	const char *type = (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64)
+				? "IV_INO_LBLK_64" : "IV_INO_LBLK_32";
 	struct super_block *sb = inode->i_sb;
-	int ino_bits = 64, lblk_bits = 64;
 
 	/*
 	 * IV_INO_LBLK_* exist only because of hardware limitations, and
@@ -150,17 +149,29 @@ static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy,
 			     type, sb->s_id);
 		return false;
 	}
-	if (sb->s_cop->get_ino_and_lblk_bits)
-		sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits);
-	if (ino_bits > max_ino_bits) {
+
+	/*
+	 * IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that inode numbers fit
+	 * in 32 bits.  In principle, IV_INO_LBLK_32 could support longer inode
+	 * numbers because it hashes the inode number; however, currently the
+	 * inode number is gotten from inode::i_ino which is 'unsigned long'.
+	 * So for now the implementation limit is 32 bits.
+	 */
+	if (!sb->s_cop->has_32bit_inodes) {
 		fscrypt_warn(inode,
 			     "Can't use %s policy on filesystem '%s' because its inode numbers are too long",
 			     type, sb->s_id);
 		return false;
 	}
-	if (lblk_bits > max_lblk_bits) {
+
+	/*
+	 * IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that file data unit
+	 * indices fit in 32 bits.
+	 */
+	if (fscrypt_max_file_dun_bits(sb,
+			fscrypt_policy_v2_du_bits(policy, inode)) > 32) {
 		fscrypt_warn(inode,
-			     "Can't use %s policy on filesystem '%s' because its block numbers are too long",
+			     "Can't use %s policy on filesystem '%s' because its maximum file size is too large",
 			     type, sb->s_id);
 		return false;
 	}
@@ -233,25 +244,39 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy,
 		return false;
 	}
 
+	if (policy->log2_data_unit_size) {
+		if (!inode->i_sb->s_cop->supports_subblock_data_units) {
+			fscrypt_warn(inode,
+				     "Filesystem does not support configuring crypto data unit size");
+			return false;
+		}
+		if (policy->log2_data_unit_size > inode->i_blkbits ||
+		    policy->log2_data_unit_size < SECTOR_SHIFT /* 9 */) {
+			fscrypt_warn(inode,
+				     "Unsupported log2_data_unit_size in encryption policy: %d",
+				     policy->log2_data_unit_size);
+			return false;
+		}
+		if (policy->log2_data_unit_size != inode->i_blkbits &&
+		    (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
+			/*
+			 * Not safe to enable yet, as we need to ensure that DUN
+			 * wraparound can only occur on a FS block boundary.
+			 */
+			fscrypt_warn(inode,
+				     "Sub-block data units not yet supported with IV_INO_LBLK_32");
+			return false;
+		}
+	}
+
 	if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) &&
 	    !supported_direct_key_modes(inode, policy->contents_encryption_mode,
 					policy->filenames_encryption_mode))
 		return false;
 
-	if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) &&
-	    !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_64",
-					  32, 32))
-		return false;
-
-	/*
-	 * IV_INO_LBLK_32 hashes the inode number, so in principle it can
-	 * support any ino_bits.  However, currently the inode number is gotten
-	 * from inode::i_ino which is 'unsigned long'.  So for now the
-	 * implementation limit is 32 bits.
-	 */
-	if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) &&
-	    !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32",
-					  32, 32))
+	if ((policy->flags & (FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 |
+			      FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) &&
+	    !supported_iv_ino_lblk_policy(policy, inode))
 		return false;
 
 	if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) {
@@ -330,6 +355,7 @@ static int fscrypt_new_context(union fscrypt_context *ctx_u,
 		ctx->filenames_encryption_mode =
 			policy->filenames_encryption_mode;
 		ctx->flags = policy->flags;
+		ctx->log2_data_unit_size = policy->log2_data_unit_size;
 		memcpy(ctx->master_key_identifier,
 		       policy->master_key_identifier,
 		       sizeof(ctx->master_key_identifier));
@@ -390,6 +416,7 @@ int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
 		policy->filenames_encryption_mode =
 			ctx->filenames_encryption_mode;
 		policy->flags = ctx->flags;
+		policy->log2_data_unit_size = ctx->log2_data_unit_size;
 		memcpy(policy->__reserved, ctx->__reserved,
 		       sizeof(policy->__reserved));
 		memcpy(policy->master_key_identifier,
@@ -405,11 +432,11 @@ int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
 /* Retrieve an inode's encryption policy */
 static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy)
 {
-	const struct fscrypt_info *ci;
+	const struct fscrypt_inode_info *ci;
 	union fscrypt_context ctx;
 	int ret;
 
-	ci = fscrypt_get_info(inode);
+	ci = fscrypt_get_inode_info(inode);
 	if (ci) {
 		/* key available, use the cached policy */
 		*policy = ci->ci_policy;
@@ -647,7 +674,7 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
 
 	/*
 	 * Both parent and child are encrypted, so verify they use the same
-	 * encryption policy.  Compare the fscrypt_info structs if the keys are
+	 * encryption policy.  Compare the cached policies if the keys are
 	 * available, otherwise retrieve and compare the fscrypt_contexts.
 	 *
 	 * Note that the fscrypt_context retrieval will be required frequently
@@ -717,7 +744,7 @@ const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir)
  */
 int fscrypt_context_for_new_inode(void *ctx, struct inode *inode)
 {
-	struct fscrypt_info *ci = inode->i_crypt_info;
+	struct fscrypt_inode_info *ci = inode->i_crypt_info;
 
 	BUILD_BUG_ON(sizeof(union fscrypt_context) !=
 			FSCRYPT_SET_CONTEXT_MAX_SIZE);
@@ -742,7 +769,7 @@ EXPORT_SYMBOL_GPL(fscrypt_context_for_new_inode);
  */
 int fscrypt_set_context(struct inode *inode, void *fs_data)
 {
-	struct fscrypt_info *ci = inode->i_crypt_info;
+	struct fscrypt_inode_info *ci = inode->i_crypt_info;
 	union fscrypt_context ctx;
 	int ctxsize;
 
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 453d4da5de52..7ae0b61258a7 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -232,19 +232,14 @@ static bool ext4_has_stable_inodes(struct super_block *sb)
 	return ext4_has_feature_stable_inodes(sb);
 }
 
-static void ext4_get_ino_and_lblk_bits(struct super_block *sb,
-				       int *ino_bits_ret, int *lblk_bits_ret)
-{
-	*ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count);
-	*lblk_bits_ret = 8 * sizeof(ext4_lblk_t);
-}
-
 const struct fscrypt_operations ext4_cryptops = {
-	.key_prefix		= "ext4:",
+	.needs_bounce_pages	= 1,
+	.has_32bit_inodes	= 1,
+	.supports_subblock_data_units = 1,
+	.legacy_key_prefix	= "ext4:",
 	.get_context		= ext4_get_context,
 	.set_context		= ext4_set_context,
 	.get_dummy_policy	= ext4_get_dummy_policy,
 	.empty_dir		= ext4_empty_dir,
 	.has_stable_inodes	= ext4_has_stable_inodes,
-	.get_ino_and_lblk_bits	= ext4_get_ino_and_lblk_bits,
 };
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 6172ecd95bd9..be17d77513d5 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3203,13 +3203,6 @@ static bool f2fs_has_stable_inodes(struct super_block *sb)
 	return true;
 }
 
-static void f2fs_get_ino_and_lblk_bits(struct super_block *sb,
-				       int *ino_bits_ret, int *lblk_bits_ret)
-{
-	*ino_bits_ret = 8 * sizeof(nid_t);
-	*lblk_bits_ret = 8 * sizeof(block_t);
-}
-
 static struct block_device **f2fs_get_devices(struct super_block *sb,
 					      unsigned int *num_devs)
 {
@@ -3231,13 +3224,15 @@ static struct block_device **f2fs_get_devices(struct super_block *sb,
 }
 
 static const struct fscrypt_operations f2fs_cryptops = {
-	.key_prefix		= "f2fs:",
+	.needs_bounce_pages	= 1,
+	.has_32bit_inodes	= 1,
+	.supports_subblock_data_units = 1,
+	.legacy_key_prefix	= "f2fs:",
 	.get_context		= f2fs_get_context,
 	.set_context		= f2fs_set_context,
 	.get_dummy_policy	= f2fs_get_dummy_policy,
 	.empty_dir		= f2fs_empty_dir,
 	.has_stable_inodes	= f2fs_has_stable_inodes,
-	.get_ino_and_lblk_bits	= f2fs_get_ino_and_lblk_bits,
 	.get_devices		= f2fs_get_devices,
 };
 #endif
diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c
index 3125e76376ee..921f9033d0d2 100644
--- a/fs/ubifs/crypto.c
+++ b/fs/ubifs/crypto.c
@@ -88,8 +88,7 @@ int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
 }
 
 const struct fscrypt_operations ubifs_crypt_operations = {
-	.flags			= FS_CFLG_OWN_PAGES,
-	.key_prefix		= "ubifs:",
+	.legacy_key_prefix	= "ubifs:",
 	.get_context		= ubifs_crypt_get_context,
 	.set_context		= ubifs_crypt_set_context,
 	.empty_dir		= ubifs_crypt_empty_dir,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2bc171fe891c..bd522c0ac267 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -67,7 +67,7 @@ struct swap_info_struct;
 struct seq_file;
 struct workqueue_struct;
 struct iov_iter;
-struct fscrypt_info;
+struct fscrypt_inode_info;
 struct fscrypt_operations;
 struct fsverity_info;
 struct fsverity_operations;
@@ -738,7 +738,7 @@ struct inode {
 #endif
 
 #ifdef CONFIG_FS_ENCRYPTION
-	struct fscrypt_info	*i_crypt_info;
+	struct fscrypt_inode_info	*i_crypt_info;
 #endif
 
 #ifdef CONFIG_FS_VERITY
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index c895b12737a1..12f9e455d569 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -31,7 +31,7 @@
 #define FSCRYPT_CONTENTS_ALIGNMENT 16
 
 union fscrypt_policy;
-struct fscrypt_info;
+struct fscrypt_inode_info;
 struct fs_parameter;
 struct seq_file;
 
@@ -59,26 +59,55 @@ struct fscrypt_name {
 
 #ifdef CONFIG_FS_ENCRYPTION
 
-/*
- * If set, the fscrypt bounce page pool won't be allocated (unless another
- * filesystem needs it).  Set this if the filesystem always uses its own bounce
- * pages for writes and therefore won't need the fscrypt bounce page pool.
- */
-#define FS_CFLG_OWN_PAGES (1U << 1)
-
 /* Crypto operations for filesystems */
 struct fscrypt_operations {
 
-	/* Set of optional flags; see above for allowed flags */
-	unsigned int flags;
+	/*
+	 * If set, then fs/crypto/ will allocate a global bounce page pool the
+	 * first time an encryption key is set up for a file.  The bounce page
+	 * pool is required by the following functions:
+	 *
+	 * - fscrypt_encrypt_pagecache_blocks()
+	 * - fscrypt_zeroout_range() for files not using inline crypto
+	 *
+	 * If the filesystem doesn't use those, it doesn't need to set this.
+	 */
+	unsigned int needs_bounce_pages : 1;
 
 	/*
-	 * If set, this is a filesystem-specific key description prefix that
-	 * will be accepted for "logon" keys for v1 fscrypt policies, in
-	 * addition to the generic prefix "fscrypt:".  This functionality is
-	 * deprecated, so new filesystems shouldn't set this field.
+	 * If set, then fs/crypto/ will allow the use of encryption settings
+	 * that assume inode numbers fit in 32 bits (i.e.
+	 * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64}), provided that the other
+	 * prerequisites for these settings are also met.  This is only useful
+	 * if the filesystem wants to support inline encryption hardware that is
+	 * limited to 32-bit or 64-bit data unit numbers and where programming
+	 * keyslots is very slow.
 	 */
-	const char *key_prefix;
+	unsigned int has_32bit_inodes : 1;
+
+	/*
+	 * If set, then fs/crypto/ will allow users to select a crypto data unit
+	 * size that is less than the filesystem block size.  This is done via
+	 * the log2_data_unit_size field of the fscrypt policy.  This flag is
+	 * not compatible with filesystems that encrypt variable-length blocks
+	 * (i.e. blocks that aren't all equal to filesystem's block size), for
+	 * example as a result of compression.  It's also not compatible with
+	 * the fscrypt_encrypt_block_inplace() and
+	 * fscrypt_decrypt_block_inplace() functions.
+	 */
+	unsigned int supports_subblock_data_units : 1;
+
+	/*
+	 * This field exists only for backwards compatibility reasons and should
+	 * only be set by the filesystems that are setting it already.  It
+	 * contains the filesystem-specific key description prefix that is
+	 * accepted for "logon" keys for v1 fscrypt policies.  This
+	 * functionality is deprecated in favor of the generic prefix
+	 * "fscrypt:", which itself is deprecated in favor of the filesystem
+	 * keyring ioctls such as FS_IOC_ADD_ENCRYPTION_KEY.  Filesystems that
+	 * are newly adding fscrypt support should not set this field.
+	 */
+	const char *legacy_key_prefix;
 
 	/*
 	 * Get the fscrypt context of the given inode.
@@ -146,21 +175,6 @@ struct fscrypt_operations {
 	bool (*has_stable_inodes)(struct super_block *sb);
 
 	/*
-	 * Get the number of bits that the filesystem uses to represent inode
-	 * numbers and file logical block numbers.
-	 *
-	 * By default, both of these are assumed to be 64-bit.  This function
-	 * can be implemented to declare that either or both of these numbers is
-	 * shorter, which may allow the use of the
-	 * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags and/or the use of
-	 * inline crypto hardware whose maximum DUN length is less than 64 bits
-	 * (e.g., eMMC v5.2 spec compliant hardware).  This function only needs
-	 * to be implemented if support for one of these features is needed.
-	 */
-	void (*get_ino_and_lblk_bits)(struct super_block *sb,
-				      int *ino_bits_ret, int *lblk_bits_ret);
-
-	/*
 	 * Return an array of pointers to the block devices to which the
 	 * filesystem may write encrypted file contents, NULL if the filesystem
 	 * only has a single such block device, or an ERR_PTR() on error.
@@ -178,7 +192,8 @@ struct fscrypt_operations {
 					     unsigned int *num_devs);
 };
 
-static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode)
+static inline struct fscrypt_inode_info *
+fscrypt_get_inode_info(const struct inode *inode)
 {
 	/*
 	 * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info().
@@ -390,7 +405,8 @@ static inline void fscrypt_set_ops(struct super_block *sb,
 }
 #else  /* !CONFIG_FS_ENCRYPTION */
 
-static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode)
+static inline struct fscrypt_inode_info *
+fscrypt_get_inode_info(const struct inode *inode)
 {
 	return NULL;
 }
@@ -868,7 +884,7 @@ static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
  */
 static inline bool fscrypt_has_encryption_key(const struct inode *inode)
 {
-	return fscrypt_get_info(inode) != NULL;
+	return fscrypt_get_inode_info(inode) != NULL;
 }
 
 /**
diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h
index fd1fb0d5389d..7a8f4c290187 100644
--- a/include/uapi/linux/fscrypt.h
+++ b/include/uapi/linux/fscrypt.h
@@ -71,7 +71,8 @@ struct fscrypt_policy_v2 {
 	__u8 contents_encryption_mode;
 	__u8 filenames_encryption_mode;
 	__u8 flags;
-	__u8 __reserved[4];
+	__u8 log2_data_unit_size;
+	__u8 __reserved[3];
 	__u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
 };