[RFC PATCH 00/14] Consolidate Post read processing code

[RFC PATCH 00/14] Consolidate Post read processing code

[Chandan Rajendra]

This patchset moves the "post read processing" code into a file of its
own (i.e. fs/post_read_process.c) and modifies the generic
do_mpage_readpge() to make use of the functionality provided. With
these changes in place, the patchset changes Ext4 to use
mpage_readpage[s] instead of its own custom ext4_readpage[s]()
functions. This is done to reduce duplicity of code across
filesystems. Also, Post read processing sources will be built only if
one of CONFIG_FS_ENCRYPTION and CONFIG_FS_VERITY is enabled.

Members of "struct fscrypt_ctx" that tracked status of a "write"
operation are now made an anonymous structure since the decryption
state tracking members are now moved into "struct post_read_ctx".

The patchset also modifies fs/buffer.c and fscrypt functionality to
get file encryption/decryption to work with subpage-sized blocks.

The following fixes from Eric Biggers are prerequisites for this
patchset,
  fscrypt: fix race where ->lookup() marks plaintext dentry as ciphertext
  fscrypt: only set dentry_operations on ciphertext dentries
  fscrypt: clear DCACHE_ENCRYPTED_NAME when unaliasing directory
  fscrypt: fix race allowing rename() and link() of ciphertext dentries
  fscrypt: clean up and improve dentry revalidation

The patches can also be obtained from,
"https://github.com/chandanr/linux.git subpage-encryption"

TODO:
1. The subset of the fscrypt_encrypt_page() that deals with
   FS_CFLG_OWN_PAGES case still needs to be tested. UBIFS seems to be the
   only user of this piece of code.
2. Verity changes needs to be added for F2FS and I will add them in the
   next patchset based on the review comments obtained for the current
   patchset.

Chandan Rajendra (14):
  ext4: Clear BH_Uptodate flag on decryption error
  Consolidate "post read processing" into a new file
  fsverity: Add call back to decide if verity check has to be performed
  fsverity: Add call back to determine readpage limit
  fs/mpage.c: Integrate post read processing
  ext4: Wire up ext4_readpage[s] to use mpage_readpage[s]
  Remove the term "bio" from post read processing
  Add decryption support for sub-pagesized blocks
  ext4: Decrypt all boundary blocks when doing buffered write
  ext4: Decrypt the block that needs to be partially zeroed
  fscrypt_encrypt_page: Loop across all blocks mapped by a page range
  ext4: Compute logical block and the page range to be encrypted
  fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page
  ext4: Enable encryption for subpage-sized blocks

 Documentation/filesystems/fscrypt.rst |   4 +-
 fs/Makefile                           |   4 +
 fs/buffer.c                           |  82 +++--
 fs/crypto/bio.c                       | 109 ++++---
 fs/crypto/crypto.c                    |  73 +++--
 fs/crypto/fscrypt_private.h           |   3 +
 fs/ext4/Makefile                      |   2 +-
 fs/ext4/ext4.h                        |   2 -
 fs/ext4/inode.c                       |  47 ++-
 fs/ext4/page-io.c                     |   9 +-
 fs/ext4/readpage.c                    | 445 --------------------------
 fs/ext4/super.c                       |  40 ++-
 fs/f2fs/data.c                        | 148 ++-------
 fs/f2fs/super.c                       |   9 +-
 fs/mpage.c                            |  45 ++-
 fs/post_read_process.c                | 155 +++++++++
 fs/verity/verify.c                    |  12 +
 include/linux/buffer_head.h           |   1 +
 include/linux/fscrypt.h               |  20 +-
 include/linux/fsverity.h              |   2 +
 include/linux/post_read_process.h     |  22 ++
 21 files changed, 503 insertions(+), 731 deletions(-)
 delete mode 100644 fs/ext4/readpage.c
 create mode 100644 fs/post_read_process.c
 create mode 100644 include/linux/post_read_process.h

-- 
2.19.1

[RFC PATCH 01/14] ext4: Clear BH_Uptodate flag on decryption error

[Chandan Rajendra]

On an error return from fscrypt_decrypt_page(), ext4_block_write_begin()
can return with the page's buffer_head marked with BH_Uptodate
flag. This commit clears the BH_Uptodate flag in such cases.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/ext4/inode.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3c2e7f5a6c84..05b258db8673 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1225,11 +1225,15 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
 		if (!buffer_uptodate(*wait_bh))
 			err = -EIO;
 	}
-	if (unlikely(err))
+	if (unlikely(err)) {
 		page_zero_new_buffers(page, from, to);
-	else if (decrypt)
+	} else if (decrypt) {
 		err = fscrypt_decrypt_page(page->mapping->host, page,
 				PAGE_SIZE, 0, page->index);
+		if (err)
+			clear_buffer_uptodate(*wait_bh);
+	}
+
 	return err;
 }
 #endif
-- 
2.19.1

[RFC PATCH 02/14] Consolidate "post read processing" into a new file

[Chandan Rajendra]

The post read processing code is used by both Ext4 and F2FS. Hence to
remove duplicity, this commit moves the code into
include/linux/post_read_process.h and fs/post_read_process.c.

The corresponding decrypt and verity "work" functions have been moved
inside fscrypt and fsverity sources. With these in place, the post
processing code now has to just invoke enqueue functions provided by
fscrypt and fsverity.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/Makefile                       |   4 +
 fs/crypto/bio.c                   |  23 ++---
 fs/crypto/crypto.c                |  17 ++--
 fs/crypto/fscrypt_private.h       |   3 +
 fs/ext4/ext4.h                    |   2 -
 fs/ext4/readpage.c                | 154 +-----------------------------
 fs/ext4/super.c                   |   9 +-
 fs/f2fs/data.c                    | 146 ++++------------------------
 fs/f2fs/super.c                   |   9 +-
 fs/post_read_process.c            | 136 ++++++++++++++++++++++++++
 fs/verity/verify.c                |  12 +++
 include/linux/fscrypt.h           |  20 +---
 include/linux/post_read_process.h |  21 ++++
 13 files changed, 220 insertions(+), 336 deletions(-)
 create mode 100644 fs/post_read_process.c
 create mode 100644 include/linux/post_read_process.h

diff --git a/fs/Makefile b/fs/Makefile
index 9dd2186e74b5..f9abc3f71d3c 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -21,6 +21,10 @@ else
 obj-y +=	no-block.o
 endif
 
+ifeq (y, $(firstword $(filter y,$(CONFIG_FS_ENCRYPTION) $(CONFIG_FS_VERITY))))
+obj-y +=	post_read_process.o
+endif
+
 obj-$(CONFIG_PROC_FS) += proc_namespace.o
 
 obj-y				+= notify/
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index 5759bcd018cd..3e40d65ae6a8 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -24,6 +24,8 @@
 #include <linux/module.h>
 #include <linux/bio.h>
 #include <linux/namei.h>
+#include <linux/post_read_process.h>
+
 #include "fscrypt_private.h"
 
 static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
@@ -54,24 +56,15 @@ void fscrypt_decrypt_bio(struct bio *bio)
 }
 EXPORT_SYMBOL(fscrypt_decrypt_bio);
 
-static void completion_pages(struct work_struct *work)
+void fscrypt_decrypt_work(struct work_struct *work)
 {
-	struct fscrypt_ctx *ctx =
-		container_of(work, struct fscrypt_ctx, r.work);
-	struct bio *bio = ctx->r.bio;
+	struct bio_post_read_ctx *ctx =
+		container_of(work, struct bio_post_read_ctx, work);
 
-	__fscrypt_decrypt_bio(bio, true);
-	fscrypt_release_ctx(ctx);
-	bio_put(bio);
-}
+	fscrypt_decrypt_bio(ctx->bio);
 
-void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, struct bio *bio)
-{
-	INIT_WORK(&ctx->r.work, completion_pages);
-	ctx->r.bio = bio;
-	fscrypt_enqueue_decrypt_work(&ctx->r.work);
+	bio_post_read_processing(ctx);
 }
-EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio);
 
 void fscrypt_pullback_bio_page(struct page **page, bool restore)
 {
@@ -87,7 +80,7 @@ void fscrypt_pullback_bio_page(struct page **page, bool restore)
 	ctx = (struct fscrypt_ctx *)page_private(bounce_page);
 
 	/* restore control page */
-	*page = ctx->w.control_page;
+	*page = ctx->control_page;
 
 	if (restore)
 		fscrypt_restore_control_page(bounce_page);
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 3fc84bf2b1e5..ffa9302a7351 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -53,6 +53,7 @@ struct kmem_cache *fscrypt_info_cachep;
 
 void fscrypt_enqueue_decrypt_work(struct work_struct *work)
 {
+	INIT_WORK(work, fscrypt_decrypt_work);
 	queue_work(fscrypt_read_workqueue, work);
 }
 EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work);
@@ -70,11 +71,11 @@ void fscrypt_release_ctx(struct fscrypt_ctx *ctx)
 {
 	unsigned long flags;
 
-	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;
+	if (ctx->flags & FS_CTX_HAS_BOUNCE_BUFFER_FL && ctx->bounce_page) {
+		mempool_free(ctx->bounce_page, fscrypt_bounce_page_pool);
+		ctx->bounce_page = NULL;
 	}
-	ctx->w.control_page = NULL;
+	ctx->control_page = NULL;
 	if (ctx->flags & FS_CTX_REQUIRES_FREE_ENCRYPT_FL) {
 		kmem_cache_free(fscrypt_ctx_cachep, ctx);
 	} else {
@@ -194,11 +195,11 @@ int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw,
 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)
+	ctx->bounce_page = mempool_alloc(fscrypt_bounce_page_pool, gfp_flags);
+	if (ctx->bounce_page == NULL)
 		return ERR_PTR(-ENOMEM);
 	ctx->flags |= FS_CTX_HAS_BOUNCE_BUFFER_FL;
-	return ctx->w.bounce_page;
+	return ctx->bounce_page;
 }
 
 /**
@@ -267,7 +268,7 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
 	if (IS_ERR(ciphertext_page))
 		goto errout;
 
-	ctx->w.control_page = page;
+	ctx->control_page = page;
 	err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num,
 				     page, ciphertext_page, len, offs,
 				     gfp_flags);
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 7da276159593..412a3bcf9efd 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -114,6 +114,9 @@ static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
 	return false;
 }
 
+/* bio.c */
+void fscrypt_decrypt_work(struct work_struct *work);
+
 /* crypto.c */
 extern struct kmem_cache *fscrypt_info_cachep;
 extern int fscrypt_initialize(unsigned int cop_flags);
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index f2b0e628ff7b..23f8568c9b53 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3127,8 +3127,6 @@ static inline void ext4_set_de_type(struct super_block *sb,
 extern int ext4_mpage_readpages(struct address_space *mapping,
 				struct list_head *pages, struct page *page,
 				unsigned nr_pages, bool is_readahead);
-extern int __init ext4_init_post_read_processing(void);
-extern void ext4_exit_post_read_processing(void);
 
 /* symlink.c */
 extern const struct inode_operations ext4_encrypted_symlink_inode_operations;
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index 0169e3809da3..8943fc41fd33 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -44,14 +44,10 @@
 #include <linux/backing-dev.h>
 #include <linux/pagevec.h>
 #include <linux/cleancache.h>
+#include <linux/post_read_process.h>
 
 #include "ext4.h"
 
-#define NUM_PREALLOC_POST_READ_CTXS	128
-
-static struct kmem_cache *bio_post_read_ctx_cache;
-static mempool_t *bio_post_read_ctx_pool;
-
 static inline bool ext4_bio_encrypted(struct bio *bio)
 {
 #ifdef CONFIG_FS_ENCRYPTION
@@ -61,125 +57,6 @@ static inline bool ext4_bio_encrypted(struct bio *bio)
 #endif
 }
 
-/* postprocessing steps for read bios */
-enum bio_post_read_step {
-	STEP_INITIAL = 0,
-	STEP_DECRYPT,
-	STEP_VERITY,
-};
-
-struct bio_post_read_ctx {
-	struct bio *bio;
-	struct work_struct work;
-	unsigned int cur_step;
-	unsigned int enabled_steps;
-};
-
-static void __read_end_io(struct bio *bio)
-{
-	struct page *page;
-	struct bio_vec *bv;
-	int i;
-	struct bvec_iter_all iter_all;
-
-	bio_for_each_segment_all(bv, bio, i, iter_all) {
-		page = bv->bv_page;
-
-		/* PG_error was set if any post_read step failed */
-		if (bio->bi_status || PageError(page)) {
-			ClearPageUptodate(page);
-			SetPageError(page);
-		} else {
-			SetPageUptodate(page);
-		}
-		unlock_page(page);
-	}
-	if (bio->bi_private)
-		mempool_free(bio->bi_private, bio_post_read_ctx_pool);
-	bio_put(bio);
-}
-
-static void bio_post_read_processing(struct bio_post_read_ctx *ctx);
-
-static void decrypt_work(struct work_struct *work)
-{
-	struct bio_post_read_ctx *ctx =
-		container_of(work, struct bio_post_read_ctx, work);
-
-	fscrypt_decrypt_bio(ctx->bio);
-
-	bio_post_read_processing(ctx);
-}
-
-static void verity_work(struct work_struct *work)
-{
-	struct bio_post_read_ctx *ctx =
-		container_of(work, struct bio_post_read_ctx, work);
-
-	fsverity_verify_bio(ctx->bio);
-
-	bio_post_read_processing(ctx);
-}
-
-static void bio_post_read_processing(struct bio_post_read_ctx *ctx)
-{
-	/*
-	 * We use different work queues for decryption and for verity because
-	 * verity may require reading metadata pages that need decryption, and
-	 * we shouldn't recurse to the same workqueue.
-	 */
-	switch (++ctx->cur_step) {
-	case STEP_DECRYPT:
-		if (ctx->enabled_steps & (1 << STEP_DECRYPT)) {
-			INIT_WORK(&ctx->work, decrypt_work);
-			fscrypt_enqueue_decrypt_work(&ctx->work);
-			return;
-		}
-		ctx->cur_step++;
-		/* fall-through */
-	case STEP_VERITY:
-		if (ctx->enabled_steps & (1 << STEP_VERITY)) {
-			INIT_WORK(&ctx->work, verity_work);
-			fsverity_enqueue_verify_work(&ctx->work);
-			return;
-		}
-		ctx->cur_step++;
-		/* fall-through */
-	default:
-		__read_end_io(ctx->bio);
-	}
-}
-
-static struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
-						       struct bio *bio,
-						       pgoff_t index)
-{
-	unsigned int post_read_steps = 0;
-	struct bio_post_read_ctx *ctx = NULL;
-
-	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
-		post_read_steps |= 1 << STEP_DECRYPT;
-#ifdef CONFIG_FS_VERITY
-	if (inode->i_verity_info != NULL &&
-	    (index < ((i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT)))
-		post_read_steps |= 1 << STEP_VERITY;
-#endif
-	if (post_read_steps) {
-		ctx = mempool_alloc(bio_post_read_ctx_pool, GFP_NOFS);
-		if (!ctx)
-			return ERR_PTR(-ENOMEM);
-		ctx->bio = bio;
-		ctx->enabled_steps = post_read_steps;
-		bio->bi_private = ctx;
-	}
-	return ctx;
-}
-
-static bool bio_post_read_required(struct bio *bio)
-{
-	return bio->bi_private && !bio->bi_status;
-}
-
 /*
  * I/O completion handler for multipage BIOs.
  *
@@ -197,11 +74,10 @@ static void mpage_end_io(struct bio *bio)
 	if (bio_post_read_required(bio)) {
 		struct bio_post_read_ctx *ctx = bio->bi_private;
 
-		ctx->cur_step = STEP_INITIAL;
 		bio_post_read_processing(ctx);
 		return;
 	}
-	__read_end_io(bio);
+	end_bio_post_read_processing(bio);
 }
 
 static inline loff_t ext4_readpage_limit(struct inode *inode)
@@ -417,29 +293,3 @@ int ext4_mpage_readpages(struct address_space *mapping,
 		submit_bio(bio);
 	return 0;
 }
-
-int __init ext4_init_post_read_processing(void)
-{
-	bio_post_read_ctx_cache =
-		kmem_cache_create("ext4_bio_post_read_ctx",
-				  sizeof(struct bio_post_read_ctx), 0, 0, NULL);
-	if (!bio_post_read_ctx_cache)
-		goto fail;
-	bio_post_read_ctx_pool =
-		mempool_create_slab_pool(NUM_PREALLOC_POST_READ_CTXS,
-					 bio_post_read_ctx_cache);
-	if (!bio_post_read_ctx_pool)
-		goto fail_free_cache;
-	return 0;
-
-fail_free_cache:
-	kmem_cache_destroy(bio_post_read_ctx_cache);
-fail:
-	return -ENOMEM;
-}
-
-void ext4_exit_post_read_processing(void)
-{
-	mempool_destroy(bio_post_read_ctx_pool);
-	kmem_cache_destroy(bio_post_read_ctx_cache);
-}
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4ae6f5849caa..aba724f82cc3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -6101,10 +6101,6 @@ static int __init ext4_init_fs(void)
 		return err;
 
 	err = ext4_init_pending();
-	if (err)
-		goto out7;
-
-	err = ext4_init_post_read_processing();
 	if (err)
 		goto out6;
 
@@ -6146,10 +6142,8 @@ static int __init ext4_init_fs(void)
 out4:
 	ext4_exit_pageio();
 out5:
-	ext4_exit_post_read_processing();
-out6:
 	ext4_exit_pending();
-out7:
+out6:
 	ext4_exit_es();
 
 	return err;
@@ -6166,7 +6160,6 @@ static void __exit ext4_exit_fs(void)
 	ext4_exit_sysfs();
 	ext4_exit_system_zone();
 	ext4_exit_pageio();
-	ext4_exit_post_read_processing();
 	ext4_exit_es();
 	ext4_exit_pending();
 }
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 038b958d0fa9..2f62244f6d24 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -18,6 +18,7 @@
 #include <linux/uio.h>
 #include <linux/cleancache.h>
 #include <linux/sched/signal.h>
+#include <linux/post_read_process.h>
 
 #include "f2fs.h"
 #include "node.h"
@@ -25,11 +26,6 @@
 #include "trace.h"
 #include <trace/events/f2fs.h>
 
-#define NUM_PREALLOC_POST_READ_CTXS	128
-
-static struct kmem_cache *bio_post_read_ctx_cache;
-static mempool_t *bio_post_read_ctx_pool;
-
 static bool __is_cp_guaranteed(struct page *page)
 {
 	struct address_space *mapping = page->mapping;
@@ -69,20 +65,6 @@ static enum count_type __read_io_type(struct page *page)
 	return F2FS_RD_DATA;
 }
 
-/* postprocessing steps for read bios */
-enum bio_post_read_step {
-	STEP_INITIAL = 0,
-	STEP_DECRYPT,
-	STEP_VERITY,
-};
-
-struct bio_post_read_ctx {
-	struct bio *bio;
-	struct work_struct work;
-	unsigned int cur_step;
-	unsigned int enabled_steps;
-};
-
 static void __read_end_io(struct bio *bio)
 {
 	struct page *page;
@@ -104,65 +86,16 @@ static void __read_end_io(struct bio *bio)
 		dec_page_count(F2FS_P_SB(page), __read_io_type(page));
 		unlock_page(page);
 	}
-	if (bio->bi_private)
-		mempool_free(bio->bi_private, bio_post_read_ctx_pool);
-	bio_put(bio);
-}
-
-static void bio_post_read_processing(struct bio_post_read_ctx *ctx);
 
-static void decrypt_work(struct work_struct *work)
-{
-	struct bio_post_read_ctx *ctx =
-		container_of(work, struct bio_post_read_ctx, work);
-
-	fscrypt_decrypt_bio(ctx->bio);
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+	if (bio->bi_private) {
+		struct bio_post_read_ctx *ctx;
 
-	bio_post_read_processing(ctx);
-}
-
-static void verity_work(struct work_struct *work)
-{
-	struct bio_post_read_ctx *ctx =
-		container_of(work, struct bio_post_read_ctx, work);
-
-	fsverity_verify_bio(ctx->bio);
-
-	bio_post_read_processing(ctx);
-}
-
-static void bio_post_read_processing(struct bio_post_read_ctx *ctx)
-{
-	/*
-	 * We use different work queues for decryption and for verity because
-	 * verity may require reading metadata pages that need decryption, and
-	 * we shouldn't recurse to the same workqueue.
-	 */
-	switch (++ctx->cur_step) {
-	case STEP_DECRYPT:
-		if (ctx->enabled_steps & (1 << STEP_DECRYPT)) {
-			INIT_WORK(&ctx->work, decrypt_work);
-			fscrypt_enqueue_decrypt_work(&ctx->work);
-			return;
-		}
-		ctx->cur_step++;
-		/* fall-through */
-	case STEP_VERITY:
-		if (ctx->enabled_steps & (1 << STEP_VERITY)) {
-			INIT_WORK(&ctx->work, verity_work);
-			fsverity_enqueue_verify_work(&ctx->work);
-			return;
-		}
-		ctx->cur_step++;
-		/* fall-through */
-	default:
-		__read_end_io(ctx->bio);
+		ctx = bio->bi_private;
+		put_bio_post_read_ctx(ctx);
 	}
-}
-
-static bool f2fs_bio_post_read_required(struct bio *bio)
-{
-	return bio->bi_private && !bio->bi_status;
+#endif
+	bio_put(bio);
 }
 
 static void f2fs_read_end_io(struct bio *bio)
@@ -173,14 +106,12 @@ static void f2fs_read_end_io(struct bio *bio)
 		bio->bi_status = BLK_STS_IOERR;
 	}
 
-	if (f2fs_bio_post_read_required(bio)) {
-		struct bio_post_read_ctx *ctx = bio->bi_private;
-
-		ctx->cur_step = STEP_INITIAL;
-		bio_post_read_processing(ctx);
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+	if (!bio->bi_status && bio->bi_private) {
+		bio_post_read_processing((struct bio_post_read_ctx *)(bio->bi_private));
 		return;
 	}
-
+#endif
 	__read_end_io(bio);
 }
 
@@ -582,9 +513,9 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct bio *bio;
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
 	struct bio_post_read_ctx *ctx;
-	unsigned int post_read_steps = 0;
-
+#endif
 	if (!f2fs_is_valid_blkaddr(sbi, blkaddr, DATA_GENERIC))
 		return ERR_PTR(-EFAULT);
 
@@ -595,24 +526,13 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 	bio->bi_end_io = f2fs_read_end_io;
 	bio_set_op_attrs(bio, REQ_OP_READ, op_flag);
 
-	if (f2fs_encrypted_file(inode))
-		post_read_steps |= 1 << STEP_DECRYPT;
-#ifdef CONFIG_FS_VERITY
-	if (inode->i_verity_info != NULL &&
-	    (first_idx < ((i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT)))
-		post_read_steps |= 1 << STEP_VERITY;
-#endif
-	if (post_read_steps) {
-		ctx = mempool_alloc(bio_post_read_ctx_pool, GFP_NOFS);
-		if (!ctx) {
-			bio_put(bio);
-			return ERR_PTR(-ENOMEM);
-		}
-		ctx->bio = bio;
-		ctx->enabled_steps = post_read_steps;
-		bio->bi_private = ctx;
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+	ctx = get_bio_post_read_ctx(inode, bio, first_idx);
+	if (IS_ERR(ctx)) {
+		bio_put(bio);
+		return (struct bio *)ctx;
 	}
-
+#endif
 	return bio;
 }
 
@@ -2894,29 +2814,3 @@ void f2fs_clear_page_cache_dirty_tag(struct page *page)
 						PAGECACHE_TAG_DIRTY);
 	xa_unlock_irqrestore(&mapping->i_pages, flags);
 }
-
-int __init f2fs_init_post_read_processing(void)
-{
-	bio_post_read_ctx_cache =
-		kmem_cache_create("f2fs_bio_post_read_ctx",
-				  sizeof(struct bio_post_read_ctx), 0, 0, NULL);
-	if (!bio_post_read_ctx_cache)
-		goto fail;
-	bio_post_read_ctx_pool =
-		mempool_create_slab_pool(NUM_PREALLOC_POST_READ_CTXS,
-					 bio_post_read_ctx_cache);
-	if (!bio_post_read_ctx_pool)
-		goto fail_free_cache;
-	return 0;
-
-fail_free_cache:
-	kmem_cache_destroy(bio_post_read_ctx_cache);
-fail:
-	return -ENOMEM;
-}
-
-void __exit f2fs_destroy_post_read_processing(void)
-{
-	mempool_destroy(bio_post_read_ctx_pool);
-	kmem_cache_destroy(bio_post_read_ctx_cache);
-}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 0e187f67b206..2f75f06c784a 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3633,15 +3633,11 @@ static int __init init_f2fs_fs(void)
 	err = register_filesystem(&f2fs_fs_type);
 	if (err)
 		goto free_shrinker;
+
 	f2fs_create_root_stats();
-	err = f2fs_init_post_read_processing();
-	if (err)
-		goto free_root_stats;
+
 	return 0;
 
-free_root_stats:
-	f2fs_destroy_root_stats();
-	unregister_filesystem(&f2fs_fs_type);
 free_shrinker:
 	unregister_shrinker(&f2fs_shrinker_info);
 free_sysfs:
@@ -3662,7 +3658,6 @@ static int __init init_f2fs_fs(void)
 
 static void __exit exit_f2fs_fs(void)
 {
-	f2fs_destroy_post_read_processing();
 	f2fs_destroy_root_stats();
 	unregister_filesystem(&f2fs_fs_type);
 	unregister_shrinker(&f2fs_shrinker_info);
diff --git a/fs/post_read_process.c b/fs/post_read_process.c
new file mode 100644
index 000000000000..d203fc263091
--- /dev/null
+++ b/fs/post_read_process.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file tracks the state machine that needs to be executed after reading
+ * data from files that are encrypted and/or have verity metadata associated
+ * with them.
+ */
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/bio.h>
+#include <linux/fscrypt.h>
+#include <linux/fsverity.h>
+#include <linux/post_read_process.h>
+
+#define NUM_PREALLOC_POST_READ_CTXS	128
+
+static struct kmem_cache *bio_post_read_ctx_cache;
+static mempool_t *bio_post_read_ctx_pool;
+
+/* postprocessing steps for read bios */
+enum bio_post_read_step {
+	STEP_INITIAL = 0,
+	STEP_DECRYPT,
+	STEP_VERITY,
+};
+
+void end_bio_post_read_processing(struct bio *bio)
+{
+	struct page *page;
+	struct bio_vec *bv;
+	int i;
+	struct bvec_iter_all iter_all;
+
+	bio_for_each_segment_all(bv, bio, i, iter_all) {
+		page = bv->bv_page;
+
+		BUG_ON(bio->bi_status);
+
+		if (!PageError(page))
+			SetPageUptodate(page);
+
+		unlock_page(page);
+	}
+	if (bio->bi_private)
+		put_bio_post_read_ctx(bio->bi_private);
+	bio_put(bio);
+}
+EXPORT_SYMBOL(end_bio_post_read_processing);
+
+void bio_post_read_processing(struct bio_post_read_ctx *ctx)
+{
+	/*
+	 * We use different work queues for decryption and for verity because
+	 * verity may require reading metadata pages that need decryption, and
+	 * we shouldn't recurse to the same workqueue.
+	 */
+	switch (++ctx->cur_step) {
+	case STEP_DECRYPT:
+		if (ctx->enabled_steps & (1 << STEP_DECRYPT)) {
+			fscrypt_enqueue_decrypt_work(&ctx->work);
+			return;
+		}
+		ctx->cur_step++;
+		/* fall-through */
+	case STEP_VERITY:
+		if (ctx->enabled_steps & (1 << STEP_VERITY)) {
+			fsverity_enqueue_verify_work(&ctx->work);
+			return;
+		}
+		ctx->cur_step++;
+		/* fall-through */
+	default:
+		end_bio_post_read_processing(ctx->bio);
+	}
+}
+EXPORT_SYMBOL(bio_post_read_processing);
+
+struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
+						struct bio *bio,
+						pgoff_t index)
+{
+	unsigned int post_read_steps = 0;
+	struct bio_post_read_ctx *ctx = NULL;
+
+	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
+		post_read_steps |= 1 << STEP_DECRYPT;
+#ifdef CONFIG_FS_VERITY
+	if (inode->i_verity_info != NULL &&
+		(index < ((i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT)))
+		post_read_steps |= 1 << STEP_VERITY;
+#endif
+	if (post_read_steps) {
+		ctx = mempool_alloc(bio_post_read_ctx_pool, GFP_NOFS);
+		if (!ctx)
+			return ERR_PTR(-ENOMEM);
+		ctx->bio = bio;
+		ctx->inode = inode;
+		ctx->enabled_steps = post_read_steps;
+		ctx->cur_step = STEP_INITIAL;
+		bio->bi_private = ctx;
+	}
+	return ctx;
+}
+EXPORT_SYMBOL(get_bio_post_read_ctx);
+
+void put_bio_post_read_ctx(struct bio_post_read_ctx *ctx)
+{
+	mempool_free(ctx, bio_post_read_ctx_pool);
+}
+EXPORT_SYMBOL(put_bio_post_read_ctx);
+
+bool bio_post_read_required(struct bio *bio)
+{
+	return bio->bi_private && !bio->bi_status;
+}
+EXPORT_SYMBOL(bio_post_read_required);
+
+static int __init bio_init_post_read_processing(void)
+{
+	bio_post_read_ctx_cache = KMEM_CACHE(bio_post_read_ctx, 0);
+	if (!bio_post_read_ctx_cache)
+		goto fail;
+	bio_post_read_ctx_pool =
+		mempool_create_slab_pool(NUM_PREALLOC_POST_READ_CTXS,
+					 bio_post_read_ctx_cache);
+	if (!bio_post_read_ctx_pool)
+		goto fail_free_cache;
+	return 0;
+
+fail_free_cache:
+	kmem_cache_destroy(bio_post_read_ctx_cache);
+fail:
+	return -ENOMEM;
+}
+
+fs_initcall(bio_init_post_read_processing);
diff --git a/fs/verity/verify.c b/fs/verity/verify.c
index 5732453a81e7..f81d8ff847ec 100644
--- a/fs/verity/verify.c
+++ b/fs/verity/verify.c
@@ -13,6 +13,7 @@
 #include <linux/pagemap.h>
 #include <linux/ratelimit.h>
 #include <linux/scatterlist.h>
+#include <linux/post_read_process.h>
 
 struct workqueue_struct *fsverity_read_workqueue;
 
@@ -284,6 +285,16 @@ void fsverity_verify_bio(struct bio *bio)
 EXPORT_SYMBOL_GPL(fsverity_verify_bio);
 #endif /* CONFIG_BLOCK */
 
+static void fsverity_verify_work(struct work_struct *work)
+{
+	struct bio_post_read_ctx *ctx =
+		container_of(work, struct bio_post_read_ctx, work);
+
+	fsverity_verify_bio(ctx->bio);
+
+	bio_post_read_processing(ctx);
+}
+
 /**
  * fsverity_enqueue_verify_work - enqueue work on the fs-verity workqueue
  *
@@ -291,6 +302,7 @@ EXPORT_SYMBOL_GPL(fsverity_verify_bio);
  */
 void fsverity_enqueue_verify_work(struct work_struct *work)
 {
+	INIT_WORK(work, fsverity_verify_work);
 	queue_work(fsverity_read_workqueue, work);
 }
 EXPORT_SYMBOL_GPL(fsverity_enqueue_verify_work);
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index c00b764d6b8c..a760b7bd81d4 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -68,11 +68,7 @@ struct fscrypt_ctx {
 		struct {
 			struct page *bounce_page;	/* Ciphertext page */
 			struct page *control_page;	/* Original page  */
-		} w;
-		struct {
-			struct bio *bio;
-			struct work_struct work;
-		} r;
+		};
 		struct list_head free_list;	/* Free list */
 	};
 	u8 flags;				/* Flags */
@@ -113,7 +109,7 @@ extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned in
 
 static inline struct page *fscrypt_control_page(struct page *page)
 {
-	return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
+	return ((struct fscrypt_ctx *)page_private(page))->control_page;
 }
 
 extern void fscrypt_restore_control_page(struct page *);
@@ -218,9 +214,6 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
 }
 
 /* bio.c */
-extern void fscrypt_decrypt_bio(struct bio *);
-extern void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx,
-					struct bio *bio);
 extern void fscrypt_pullback_bio_page(struct page **, bool);
 extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
 				 unsigned int);
@@ -390,15 +383,6 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
 	return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len);
 }
 
-/* bio.c */
-static inline void fscrypt_decrypt_bio(struct bio *bio)
-{
-}
-
-static inline void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx,
-					       struct bio *bio)
-{
-}
 
 static inline void fscrypt_pullback_bio_page(struct page **page, bool restore)
 {
diff --git a/include/linux/post_read_process.h b/include/linux/post_read_process.h
new file mode 100644
index 000000000000..09e52928f861
--- /dev/null
+++ b/include/linux/post_read_process.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _POST_READ_PROCESS_H
+#define _POST_READ_PROCESS_H
+
+struct bio_post_read_ctx {
+	struct bio *bio;
+	struct inode *inode;
+	struct work_struct work;
+	unsigned int cur_step;
+	unsigned int enabled_steps;
+};
+
+void end_bio_post_read_processing(struct bio *bio);
+void bio_post_read_processing(struct bio_post_read_ctx *ctx);
+struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
+						struct bio *bio,
+						pgoff_t index);
+void put_bio_post_read_ctx(struct bio_post_read_ctx *ctx);
+bool bio_post_read_required(struct bio *bio);
+
+#endif	/* _POST_READ_PROCESS_H */
-- 
2.19.1

[RFC PATCH 03/14] fsverity: Add call back to decide if verity check has to be performed

[Chandan Rajendra]

Ext4 and F2FS store verity metadata in data extents (beyond
inode->i_size) associated with a file. But other filesystems might
choose alternative means to store verity metadata. Hence this commit
adds a callback function pointer to 'struct fsverity_operations' to help
in deciding if verity operation needs to performed against a page-cache
page holding file data.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/ext4/super.c          | 6 ++++++
 fs/post_read_process.c   | 4 +++-
 include/linux/fsverity.h | 1 +
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index aba724f82cc3..63d73b360f1d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1428,10 +1428,16 @@ static struct page *ext4_read_verity_metadata_page(struct inode *inode,
 	return read_mapping_page(inode->i_mapping, index, NULL);
 }
 
+static bool ext4_verity_required(struct inode *inode, pgoff_t index)
+{
+	return index < (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+}
+
 static const struct fsverity_operations ext4_verityops = {
 	.set_verity		= ext4_set_verity,
 	.get_metadata_end	= ext4_get_verity_metadata_end,
 	.read_metadata_page	= ext4_read_verity_metadata_page,
+	.verity_required	= ext4_verity_required,
 };
 #endif /* CONFIG_FS_VERITY */
 
diff --git a/fs/post_read_process.c b/fs/post_read_process.c
index d203fc263091..c408184b671a 100644
--- a/fs/post_read_process.c
+++ b/fs/post_read_process.c
@@ -86,7 +86,9 @@ struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
 		post_read_steps |= 1 << STEP_DECRYPT;
 #ifdef CONFIG_FS_VERITY
 	if (inode->i_verity_info != NULL &&
-		(index < ((i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT)))
+		((inode->i_sb->s_vop->verity_required
+			&& inode->i_sb->s_vop->verity_required(inode, index))
+			|| (inode->i_sb->s_vop->verity_required == NULL))
 		post_read_steps |= 1 << STEP_VERITY;
 #endif
 	if (post_read_steps) {
diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h
index 7c33b42abf1b..b83712d6c79a 100644
--- a/include/linux/fsverity.h
+++ b/include/linux/fsverity.h
@@ -18,6 +18,7 @@ struct fsverity_operations {
 	int (*set_verity)(struct inode *inode, loff_t data_i_size);
 	int (*get_metadata_end)(struct inode *inode, loff_t *metadata_end_ret);
 	struct page *(*read_metadata_page)(struct inode *inode, pgoff_t index);
+	bool (*verity_required)(struct inode *inode, pgoff_t index);
 };
 
 #ifdef CONFIG_FS_VERITY
-- 
2.19.1

[RFC PATCH 04/14] fsverity: Add call back to determine readpage limit

[Chandan Rajendra]

Ext4 and F2FS store verity metadata beyond i_size. This commit adds a
call back pointer to "struct fsverity_operations" which helps in
determining the the real file size limit upto which data can be read
from the file.

This call back will be required in order to get do_mpage_readpage()
to read files having verity metadata appended beyond i_size.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/ext4/super.c          | 18 ++++++++++++++++++
 include/linux/fsverity.h |  1 +
 2 files changed, 19 insertions(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 63d73b360f1d..cadf50f9503f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1428,6 +1428,23 @@ static struct page *ext4_read_verity_metadata_page(struct inode *inode,
 	return read_mapping_page(inode->i_mapping, index, NULL);
 }
 
+static loff_t ext4_readpage_limit(struct inode *inode)
+{
+#ifdef CONFIG_FS_VERITY
+	if (IS_VERITY(inode)) {
+		if (inode->i_verity_info)
+			/* limit to end of metadata region */
+			return fsverity_full_i_size(inode);
+		/*
+		 * fsverity_info is currently being set up and no user reads are
+		 * allowed yet.  It's easiest to just not enforce a limit yet.
+		 */
+		return inode->i_sb->s_maxbytes;
+	}
+#endif
+	return i_size_read(inode);
+}
+
 static bool ext4_verity_required(struct inode *inode, pgoff_t index)
 {
 	return index < (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -1438,6 +1455,7 @@ static const struct fsverity_operations ext4_verityops = {
 	.get_metadata_end	= ext4_get_verity_metadata_end,
 	.read_metadata_page	= ext4_read_verity_metadata_page,
 	.verity_required	= ext4_verity_required,
+	.readpage_limit		= ext4_readpage_limit,
 };
 #endif /* CONFIG_FS_VERITY */
 
diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h
index b83712d6c79a..fc8113acbbfe 100644
--- a/include/linux/fsverity.h
+++ b/include/linux/fsverity.h
@@ -19,6 +19,7 @@ struct fsverity_operations {
 	int (*get_metadata_end)(struct inode *inode, loff_t *metadata_end_ret);
 	struct page *(*read_metadata_page)(struct inode *inode, pgoff_t index);
 	bool (*verity_required)(struct inode *inode, pgoff_t index);
+	loff_t (*readpage_limit)(struct inode *inode);
 };
 
 #ifdef CONFIG_FS_VERITY
-- 
2.19.1

[RFC PATCH 05/14] fs/mpage.c: Integrate post read processing

[Chandan Rajendra]

This commit adds code to make do_mpage_readpage() to be "post read
processing" aware i.e. for files requiring decryption/verification,
do_mpage_readpage() now allocates a context structure and assigns the
corresponding pointer to bio->bi_private. At endio time, a non-zero
bio->bi_private indicates that after the read operation is performed, the
bio's payload needs to be processed further before handing over the data
to user space.

The context structure is used for tracking the state machine associated
with post read processing.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/mpage.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/fs/mpage.c b/fs/mpage.c
index 3f19da75178b..b1fe1afa626e 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -30,6 +30,10 @@
 #include <linux/backing-dev.h>
 #include <linux/pagevec.h>
 #include <linux/cleancache.h>
+#include <linux/fsverity.h>
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+#include <linux/post_read_process.h>
+#endif
 #include "internal.h"
 
 /*
@@ -50,6 +54,20 @@ static void mpage_end_io(struct bio *bio)
 	int i;
 	struct bvec_iter_all iter_all;
 
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+	if (!bio->bi_status && bio->bi_private) {
+		struct bio_post_read_ctx *ctx;
+
+		ctx = bio->bi_private;
+
+		bio_post_read_processing(ctx);
+		return;
+	}
+
+	if (bio->bi_private)
+		put_bio_post_read_ctx((struct bio_post_read_ctx *)(bio->bi_private));
+#endif
+
 	bio_for_each_segment_all(bv, bio, i, iter_all) {
 		struct page *page = bv->bv_page;
 		page_endio(page, bio_op(bio),
@@ -189,7 +207,13 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 
 	block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits);
 	last_block = block_in_file + args->nr_pages * blocks_per_page;
-	last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
+#ifdef CONFIG_FS_VERITY
+	if (IS_VERITY(inode) && inode->i_sb->s_vop->readpage_limit)
+		last_block_in_file = inode->i_sb->s_vop->readpage_limit(inode);
+	else
+#endif
+		last_block_in_file = (i_size_read(inode) + blocksize - 1)
+			>> blkbits;
 	if (last_block > last_block_in_file)
 		last_block = last_block_in_file;
 	page_block = 0;
@@ -277,6 +301,10 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 	if (first_hole != blocks_per_page) {
 		zero_user_segment(page, first_hole << blkbits, PAGE_SIZE);
 		if (first_hole == 0) {
+#ifdef CONFIG_FS_VERITY
+			if (IS_VERITY(inode) && inode->i_sb->s_vop->check_hole)
+				inode->i_sb->s_vop->check_hole(inode, page);
+#endif
 			SetPageUptodate(page);
 			unlock_page(page);
 			goto out;
@@ -299,7 +327,11 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 
 alloc_new:
 	if (args->bio == NULL) {
-		if (first_hole == blocks_per_page) {
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+		struct bio_post_read_ctx *ctx;
+#endif
+		if (first_hole == blocks_per_page
+			&& !(IS_ENCRYPTED(inode) || IS_VERITY(inode))) {
 			if (!bdev_read_page(bdev, blocks[0] << (blkbits - 9),
 								page))
 				goto out;
@@ -310,6 +342,15 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 					gfp);
 		if (args->bio == NULL)
 			goto confused;
+
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+		ctx = get_bio_post_read_ctx(inode, args->bio, page->index);
+		if (IS_ERR(ctx)) {
+			bio_put(args->bio);
+			args->bio = NULL;
+			goto confused;
+		}
+#endif
 	}
 
 	length = first_hole << blkbits;
-- 
2.19.1

[RFC PATCH 06/14] ext4: Wire up ext4_readpage[s] to use mpage_readpage[s]

[Chandan Rajendra]

Now that do_mpage_readpage() is "post read process" aware, this commit
gets ext4_readpage[s] to use mpage_readpage[s] and deletes ext4's
readpage.c since the associated functionality is not required anymore.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/ext4/Makefile   |   2 +-
 fs/ext4/inode.c    |   5 +-
 fs/ext4/readpage.c | 295 ---------------------------------------------
 3 files changed, 3 insertions(+), 299 deletions(-)
 delete mode 100644 fs/ext4/readpage.c

diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 8fdfcd3c3e04..7c38803a808d 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -8,7 +8,7 @@ obj-$(CONFIG_EXT4_FS) += ext4.o
 ext4-y	:= balloc.o bitmap.o block_validity.o dir.o ext4_jbd2.o extents.o \
 		extents_status.o file.o fsmap.o fsync.o hash.o ialloc.o \
 		indirect.o inline.o inode.o ioctl.o mballoc.o migrate.o \
-		mmp.o move_extent.o namei.o page-io.o readpage.o resize.o \
+		mmp.o move_extent.o namei.o page-io.o resize.o \
 		super.o symlink.o sysfs.o xattr.o xattr_trusted.o xattr_user.o
 
 ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 05b258db8673..1327e04334df 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3353,8 +3353,7 @@ static int ext4_readpage(struct file *file, struct page *page)
 		ret = ext4_readpage_inline(inode, page);
 
 	if (ret == -EAGAIN)
-		return ext4_mpage_readpages(page->mapping, NULL, page, 1,
-						false);
+		return mpage_readpage(page, ext4_get_block);
 
 	return ret;
 }
@@ -3369,7 +3368,7 @@ ext4_readpages(struct file *file, struct address_space *mapping,
 	if (ext4_has_inline_data(inode))
 		return 0;
 
-	return ext4_mpage_readpages(mapping, pages, NULL, nr_pages, true);
+	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
 }
 
 static void ext4_invalidatepage(struct page *page, unsigned int offset,
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
deleted file mode 100644
index 8943fc41fd33..000000000000
--- a/fs/ext4/readpage.c
+++ /dev/null
@@ -1,295 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * linux/fs/ext4/readpage.c
- *
- * Copyright (C) 2002, Linus Torvalds.
- * Copyright (C) 2015, Google, Inc.
- *
- * This was originally taken from fs/mpage.c
- *
- * The intent is the ext4_mpage_readpages() function here is intended
- * to replace mpage_readpages() in the general case, not just for
- * encrypted files.  It has some limitations (see below), where it
- * will fall back to read_block_full_page(), but these limitations
- * should only be hit when page_size != block_size.
- *
- * This will allow us to attach a callback function to support ext4
- * encryption.
- *
- * If anything unusual happens, such as:
- *
- * - encountering a page which has buffers
- * - encountering a page which has a non-hole after a hole
- * - encountering a page with non-contiguous blocks
- *
- * then this code just gives up and calls the buffer_head-based read function.
- * It does handle a page which has holes at the end - that is a common case:
- * the end-of-file on blocksize < PAGE_SIZE setups.
- *
- */
-
-#include <linux/kernel.h>
-#include <linux/export.h>
-#include <linux/mm.h>
-#include <linux/kdev_t.h>
-#include <linux/gfp.h>
-#include <linux/bio.h>
-#include <linux/fs.h>
-#include <linux/buffer_head.h>
-#include <linux/blkdev.h>
-#include <linux/highmem.h>
-#include <linux/prefetch.h>
-#include <linux/mpage.h>
-#include <linux/writeback.h>
-#include <linux/backing-dev.h>
-#include <linux/pagevec.h>
-#include <linux/cleancache.h>
-#include <linux/post_read_process.h>
-
-#include "ext4.h"
-
-static inline bool ext4_bio_encrypted(struct bio *bio)
-{
-#ifdef CONFIG_FS_ENCRYPTION
-	return unlikely(bio->bi_private != NULL);
-#else
-	return false;
-#endif
-}
-
-/*
- * I/O completion handler for multipage BIOs.
- *
- * The mpage code never puts partial pages into a BIO (except for end-of-file).
- * If a page does not map to a contiguous run of blocks then it simply falls
- * back to block_read_full_page().
- *
- * Why is this?  If a page's completion depends on a number of different BIOs
- * which can complete in any order (or at the same time) then determining the
- * status of that page is hard.  See end_buffer_async_read() for the details.
- * There is no point in duplicating all that complexity.
- */
-static void mpage_end_io(struct bio *bio)
-{
-	if (bio_post_read_required(bio)) {
-		struct bio_post_read_ctx *ctx = bio->bi_private;
-
-		bio_post_read_processing(ctx);
-		return;
-	}
-	end_bio_post_read_processing(bio);
-}
-
-static inline loff_t ext4_readpage_limit(struct inode *inode)
-{
-#ifdef CONFIG_FS_VERITY
-	if (IS_VERITY(inode)) {
-		if (inode->i_verity_info)
-			/* limit to end of metadata region */
-			return fsverity_full_i_size(inode);
-		/*
-		 * fsverity_info is currently being set up and no user reads are
-		 * allowed yet.  It's easiest to just not enforce a limit yet.
-		 */
-		return inode->i_sb->s_maxbytes;
-	}
-#endif
-	return i_size_read(inode);
-}
-
-int ext4_mpage_readpages(struct address_space *mapping,
-			 struct list_head *pages, struct page *page,
-			 unsigned nr_pages, bool is_readahead)
-{
-	struct bio *bio = NULL;
-	sector_t last_block_in_bio = 0;
-
-	struct inode *inode = mapping->host;
-	const unsigned blkbits = inode->i_blkbits;
-	const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
-	const unsigned blocksize = 1 << blkbits;
-	sector_t block_in_file;
-	sector_t last_block;
-	sector_t last_block_in_file;
-	sector_t blocks[MAX_BUF_PER_PAGE];
-	unsigned page_block;
-	struct block_device *bdev = inode->i_sb->s_bdev;
-	int length;
-	unsigned relative_block = 0;
-	struct ext4_map_blocks map;
-
-	map.m_pblk = 0;
-	map.m_lblk = 0;
-	map.m_len = 0;
-	map.m_flags = 0;
-
-	for (; nr_pages; nr_pages--) {
-		int fully_mapped = 1;
-		unsigned first_hole = blocks_per_page;
-
-		prefetchw(&page->flags);
-		if (pages) {
-			page = lru_to_page(pages);
-			list_del(&page->lru);
-			if (add_to_page_cache_lru(page, mapping, page->index,
-				  readahead_gfp_mask(mapping)))
-				goto next_page;
-		}
-
-		if (page_has_buffers(page))
-			goto confused;
-
-		block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits);
-		last_block = block_in_file + nr_pages * blocks_per_page;
-		last_block_in_file = (ext4_readpage_limit(inode) +
-				      blocksize - 1) >> blkbits;
-		if (last_block > last_block_in_file)
-			last_block = last_block_in_file;
-		page_block = 0;
-
-		/*
-		 * Map blocks using the previous result first.
-		 */
-		if ((map.m_flags & EXT4_MAP_MAPPED) &&
-		    block_in_file > map.m_lblk &&
-		    block_in_file < (map.m_lblk + map.m_len)) {
-			unsigned map_offset = block_in_file - map.m_lblk;
-			unsigned last = map.m_len - map_offset;
-
-			for (relative_block = 0; ; relative_block++) {
-				if (relative_block == last) {
-					/* needed? */
-					map.m_flags &= ~EXT4_MAP_MAPPED;
-					break;
-				}
-				if (page_block == blocks_per_page)
-					break;
-				blocks[page_block] = map.m_pblk + map_offset +
-					relative_block;
-				page_block++;
-				block_in_file++;
-			}
-		}
-
-		/*
-		 * Then do more ext4_map_blocks() calls until we are
-		 * done with this page.
-		 */
-		while (page_block < blocks_per_page) {
-			if (block_in_file < last_block) {
-				map.m_lblk = block_in_file;
-				map.m_len = last_block - block_in_file;
-
-				if (ext4_map_blocks(NULL, inode, &map, 0) < 0) {
-				set_error_page:
-					SetPageError(page);
-					zero_user_segment(page, 0,
-							  PAGE_SIZE);
-					unlock_page(page);
-					goto next_page;
-				}
-			}
-			if ((map.m_flags & EXT4_MAP_MAPPED) == 0) {
-				fully_mapped = 0;
-				if (first_hole == blocks_per_page)
-					first_hole = page_block;
-				page_block++;
-				block_in_file++;
-				continue;
-			}
-			if (first_hole != blocks_per_page)
-				goto confused;		/* hole -> non-hole */
-
-			/* Contiguous blocks? */
-			if (page_block && blocks[page_block-1] != map.m_pblk-1)
-				goto confused;
-			for (relative_block = 0; ; relative_block++) {
-				if (relative_block == map.m_len) {
-					/* needed? */
-					map.m_flags &= ~EXT4_MAP_MAPPED;
-					break;
-				} else if (page_block == blocks_per_page)
-					break;
-				blocks[page_block] = map.m_pblk+relative_block;
-				page_block++;
-				block_in_file++;
-			}
-		}
-		if (first_hole != blocks_per_page) {
-			zero_user_segment(page, first_hole << blkbits,
-					  PAGE_SIZE);
-			if (first_hole == 0) {
-				if (!fsverity_check_hole(inode, page))
-					goto set_error_page;
-				SetPageUptodate(page);
-				unlock_page(page);
-				goto next_page;
-			}
-		} else if (fully_mapped) {
-			SetPageMappedToDisk(page);
-		}
-		if (fully_mapped && blocks_per_page == 1 &&
-		    !PageUptodate(page) && cleancache_get_page(page) == 0) {
-			SetPageUptodate(page);
-			goto confused;
-		}
-
-		/*
-		 * This page will go to BIO.  Do we need to send this
-		 * BIO off first?
-		 */
-		if (bio && (last_block_in_bio != blocks[0] - 1)) {
-		submit_and_realloc:
-			submit_bio(bio);
-			bio = NULL;
-		}
-		if (bio == NULL) {
-			struct bio_post_read_ctx *ctx;
-
-			bio = bio_alloc(GFP_KERNEL,
-				min_t(int, nr_pages, BIO_MAX_PAGES));
-			if (!bio)
-				goto set_error_page;
-			ctx = get_bio_post_read_ctx(inode, bio, page->index);
-			if (IS_ERR(ctx)) {
-				bio_put(bio);
-				goto set_error_page;
-			}
-			bio_set_dev(bio, bdev);
-			bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
-			bio->bi_end_io = mpage_end_io;
-			bio->bi_private = ctx;
-			bio_set_op_attrs(bio, REQ_OP_READ,
-						is_readahead ? REQ_RAHEAD : 0);
-		}
-
-		length = first_hole << blkbits;
-		if (bio_add_page(bio, page, length, 0) < length)
-			goto submit_and_realloc;
-
-		if (((map.m_flags & EXT4_MAP_BOUNDARY) &&
-		     (relative_block == map.m_len)) ||
-		    (first_hole != blocks_per_page)) {
-			submit_bio(bio);
-			bio = NULL;
-		} else
-			last_block_in_bio = blocks[blocks_per_page - 1];
-		goto next_page;
-	confused:
-		if (bio) {
-			submit_bio(bio);
-			bio = NULL;
-		}
-		if (!PageUptodate(page))
-			block_read_full_page(page, ext4_get_block);
-		else
-			unlock_page(page);
-	next_page:
-		if (pages)
-			put_page(page);
-	}
-	BUG_ON(pages && !list_empty(pages));
-	if (bio)
-		submit_bio(bio);
-	return 0;
-}
-- 
2.19.1

[RFC PATCH 07/14] Remove the term "bio" from post read processing

[Chandan Rajendra]

For block size < page size, apart from handling bios, post read
processing needs to handle buffer heads. Hence this commit removes the
term "bio" from the identifiers associated with post read processing.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/crypto/bio.c                   |  6 ++--
 fs/f2fs/data.c                    | 10 +++---
 fs/mpage.c                        | 10 +++---
 fs/post_read_process.c            | 56 +++++++++++++++----------------
 fs/verity/verify.c                |  6 ++--
 include/linux/post_read_process.h | 16 ++++-----
 6 files changed, 52 insertions(+), 52 deletions(-)

diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index 3e40d65ae6a8..bab48dfa3765 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -58,12 +58,12 @@ EXPORT_SYMBOL(fscrypt_decrypt_bio);
 
 void fscrypt_decrypt_work(struct work_struct *work)
 {
-	struct bio_post_read_ctx *ctx =
-		container_of(work, struct bio_post_read_ctx, work);
+	struct post_read_ctx *ctx =
+		container_of(work, struct post_read_ctx, work);
 
 	fscrypt_decrypt_bio(ctx->bio);
 
-	bio_post_read_processing(ctx);
+	post_read_processing(ctx);
 }
 
 void fscrypt_pullback_bio_page(struct page **page, bool restore)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 2f62244f6d24..f00f018bed27 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -89,10 +89,10 @@ static void __read_end_io(struct bio *bio)
 
 #if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
 	if (bio->bi_private) {
-		struct bio_post_read_ctx *ctx;
+		struct post_read_ctx *ctx;
 
 		ctx = bio->bi_private;
-		put_bio_post_read_ctx(ctx);
+		put_post_read_ctx(ctx);
 	}
 #endif
 	bio_put(bio);
@@ -108,7 +108,7 @@ static void f2fs_read_end_io(struct bio *bio)
 
 #if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
 	if (!bio->bi_status && bio->bi_private) {
-		bio_post_read_processing((struct bio_post_read_ctx *)(bio->bi_private));
+		post_read_processing((struct post_read_ctx *)(bio->bi_private));
 		return;
 	}
 #endif
@@ -514,7 +514,7 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct bio *bio;
 #if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
-	struct bio_post_read_ctx *ctx;
+	struct post_read_ctx *ctx;
 #endif
 	if (!f2fs_is_valid_blkaddr(sbi, blkaddr, DATA_GENERIC))
 		return ERR_PTR(-EFAULT);
@@ -527,7 +527,7 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 	bio_set_op_attrs(bio, REQ_OP_READ, op_flag);
 
 #if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
-	ctx = get_bio_post_read_ctx(inode, bio, first_idx);
+	ctx = get_post_read_ctx(inode, bio, first_idx);
 	if (IS_ERR(ctx)) {
 		bio_put(bio);
 		return (struct bio *)ctx;
diff --git a/fs/mpage.c b/fs/mpage.c
index b1fe1afa626e..3c0e484a1d2f 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -56,16 +56,16 @@ static void mpage_end_io(struct bio *bio)
 
 #if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
 	if (!bio->bi_status && bio->bi_private) {
-		struct bio_post_read_ctx *ctx;
+		struct post_read_ctx *ctx;
 
 		ctx = bio->bi_private;
 
-		bio_post_read_processing(ctx);
+		post_read_processing(ctx);
 		return;
 	}
 
 	if (bio->bi_private)
-		put_bio_post_read_ctx((struct bio_post_read_ctx *)(bio->bi_private));
+		put_post_read_ctx((struct post_read_ctx *)(bio->bi_private));
 #endif
 
 	bio_for_each_segment_all(bv, bio, i, iter_all) {
@@ -328,7 +328,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 alloc_new:
 	if (args->bio == NULL) {
 #if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
-		struct bio_post_read_ctx *ctx;
+		struct post_read_ctx *ctx;
 #endif
 		if (first_hole == blocks_per_page
 			&& !(IS_ENCRYPTED(inode) || IS_VERITY(inode))) {
@@ -344,7 +344,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 			goto confused;
 
 #if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
-		ctx = get_bio_post_read_ctx(inode, args->bio, page->index);
+		ctx = get_post_read_ctx(inode, args->bio, page->index);
 		if (IS_ERR(ctx)) {
 			bio_put(args->bio);
 			args->bio = NULL;
diff --git a/fs/post_read_process.c b/fs/post_read_process.c
index c408184b671a..f0ec1957a8b3 100644
--- a/fs/post_read_process.c
+++ b/fs/post_read_process.c
@@ -14,17 +14,17 @@
 
 #define NUM_PREALLOC_POST_READ_CTXS	128
 
-static struct kmem_cache *bio_post_read_ctx_cache;
-static mempool_t *bio_post_read_ctx_pool;
+static struct kmem_cache *post_read_ctx_cache;
+static mempool_t *post_read_ctx_pool;
 
 /* postprocessing steps for read bios */
-enum bio_post_read_step {
+enum post_read_step {
 	STEP_INITIAL = 0,
 	STEP_DECRYPT,
 	STEP_VERITY,
 };
 
-void end_bio_post_read_processing(struct bio *bio)
+void end_post_read_processing(struct bio *bio)
 {
 	struct page *page;
 	struct bio_vec *bv;
@@ -42,12 +42,12 @@ void end_bio_post_read_processing(struct bio *bio)
 		unlock_page(page);
 	}
 	if (bio->bi_private)
-		put_bio_post_read_ctx(bio->bi_private);
+		put_post_read_ctx(bio->bi_private);
 	bio_put(bio);
 }
-EXPORT_SYMBOL(end_bio_post_read_processing);
+EXPORT_SYMBOL(end_post_read_processing);
 
-void bio_post_read_processing(struct bio_post_read_ctx *ctx)
+void post_read_processing(struct post_read_ctx *ctx)
 {
 	/*
 	 * We use different work queues for decryption and for verity because
@@ -70,17 +70,17 @@ void bio_post_read_processing(struct bio_post_read_ctx *ctx)
 		ctx->cur_step++;
 		/* fall-through */
 	default:
-		end_bio_post_read_processing(ctx->bio);
+		end_post_read_processing(ctx->bio);
 	}
 }
-EXPORT_SYMBOL(bio_post_read_processing);
+EXPORT_SYMBOL(post_read_processing);
 
-struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
-						struct bio *bio,
-						pgoff_t index)
+struct post_read_ctx *get_post_read_ctx(struct inode *inode,
+					struct bio *bio,
+					pgoff_t index)
 {
 	unsigned int post_read_steps = 0;
-	struct bio_post_read_ctx *ctx = NULL;
+	struct post_read_ctx *ctx = NULL;
 
 	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
 		post_read_steps |= 1 << STEP_DECRYPT;
@@ -92,7 +92,7 @@ struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
 		post_read_steps |= 1 << STEP_VERITY;
 #endif
 	if (post_read_steps) {
-		ctx = mempool_alloc(bio_post_read_ctx_pool, GFP_NOFS);
+		ctx = mempool_alloc(post_read_ctx_pool, GFP_NOFS);
 		if (!ctx)
 			return ERR_PTR(-ENOMEM);
 		ctx->bio = bio;
@@ -103,36 +103,36 @@ struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
 	}
 	return ctx;
 }
-EXPORT_SYMBOL(get_bio_post_read_ctx);
+EXPORT_SYMBOL(get_post_read_ctx);
 
-void put_bio_post_read_ctx(struct bio_post_read_ctx *ctx)
+void put_post_read_ctx(struct post_read_ctx *ctx)
 {
-	mempool_free(ctx, bio_post_read_ctx_pool);
+	mempool_free(ctx, post_read_ctx_pool);
 }
-EXPORT_SYMBOL(put_bio_post_read_ctx);
+EXPORT_SYMBOL(put_post_read_ctx);
 
-bool bio_post_read_required(struct bio *bio)
+bool post_read_required(struct bio *bio)
 {
 	return bio->bi_private && !bio->bi_status;
 }
-EXPORT_SYMBOL(bio_post_read_required);
+EXPORT_SYMBOL(post_read_required);
 
-static int __init bio_init_post_read_processing(void)
+static int __init init_post_read_processing(void)
 {
-	bio_post_read_ctx_cache = KMEM_CACHE(bio_post_read_ctx, 0);
-	if (!bio_post_read_ctx_cache)
+	post_read_ctx_cache = KMEM_CACHE(post_read_ctx, 0);
+	if (!post_read_ctx_cache)
 		goto fail;
-	bio_post_read_ctx_pool =
+	post_read_ctx_pool =
 		mempool_create_slab_pool(NUM_PREALLOC_POST_READ_CTXS,
-					 bio_post_read_ctx_cache);
-	if (!bio_post_read_ctx_pool)
+					 post_read_ctx_cache);
+	if (!post_read_ctx_pool)
 		goto fail_free_cache;
 	return 0;
 
 fail_free_cache:
-	kmem_cache_destroy(bio_post_read_ctx_cache);
+	kmem_cache_destroy(post_read_ctx_cache);
 fail:
 	return -ENOMEM;
 }
 
-fs_initcall(bio_init_post_read_processing);
+fs_initcall(init_post_read_processing);
diff --git a/fs/verity/verify.c b/fs/verity/verify.c
index f81d8ff847ec..6cb43c538a3c 100644
--- a/fs/verity/verify.c
+++ b/fs/verity/verify.c
@@ -287,12 +287,12 @@ EXPORT_SYMBOL_GPL(fsverity_verify_bio);
 
 static void fsverity_verify_work(struct work_struct *work)
 {
-	struct bio_post_read_ctx *ctx =
-		container_of(work, struct bio_post_read_ctx, work);
+	struct post_read_ctx *ctx =
+		container_of(work, struct post_read_ctx, work);
 
 	fsverity_verify_bio(ctx->bio);
 
-	bio_post_read_processing(ctx);
+	post_read_processing(ctx);
 }
 
 /**
diff --git a/include/linux/post_read_process.h b/include/linux/post_read_process.h
index 09e52928f861..523bdecf9252 100644
--- a/include/linux/post_read_process.h
+++ b/include/linux/post_read_process.h
@@ -2,7 +2,7 @@
 #ifndef _POST_READ_PROCESS_H
 #define _POST_READ_PROCESS_H
 
-struct bio_post_read_ctx {
+struct post_read_ctx {
 	struct bio *bio;
 	struct inode *inode;
 	struct work_struct work;
@@ -10,12 +10,12 @@ struct bio_post_read_ctx {
 	unsigned int enabled_steps;
 };
 
-void end_bio_post_read_processing(struct bio *bio);
-void bio_post_read_processing(struct bio_post_read_ctx *ctx);
-struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
-						struct bio *bio,
-						pgoff_t index);
-void put_bio_post_read_ctx(struct bio_post_read_ctx *ctx);
-bool bio_post_read_required(struct bio *bio);
+void end_post_read_processing(struct bio *bio);
+void post_read_processing(struct post_read_ctx *ctx);
+struct post_read_ctx *get_post_read_ctx(struct inode *inode,
+					struct bio *bio,
+					pgoff_t index);
+void put_post_read_ctx(struct post_read_ctx *ctx);
+bool post_read_required(struct bio *bio);
 
 #endif	/* _POST_READ_PROCESS_H */
-- 
2.19.1

[RFC PATCH 08/14] Add decryption support for sub-pagesized blocks

[Chandan Rajendra]

To support decryption of sub-pagesized blocks this commit adds code to,
1. Track buffer head in "struct post_read_ctx".
2. Pass buffer head argument to all "post read" processing functions.
3. In the corresponding endio, loop across all the blocks mapped by the
   page, decrypting each block in turn.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/buffer.c                       | 82 +++++++++++++++++++++++--------
 fs/crypto/bio.c                   | 48 ++++++++++++------
 fs/crypto/crypto.c                | 19 ++++++-
 fs/f2fs/data.c                    |  2 +-
 fs/mpage.c                        |  2 +-
 fs/post_read_process.c            | 53 +++++++++++++-------
 include/linux/buffer_head.h       |  1 +
 include/linux/post_read_process.h |  5 +-
 8 files changed, 151 insertions(+), 61 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index ce357602f471..6ed1637e785d 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -45,6 +45,7 @@
 #include <linux/bit_spinlock.h>
 #include <linux/pagevec.h>
 #include <linux/sched/mm.h>
+#include <linux/post_read_process.h>
 #include <trace/events/block.h>
 
 static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
@@ -245,11 +246,7 @@ __find_get_block_slow(struct block_device *bdev, sector_t block)
 	return ret;
 }
 
-/*
- * I/O completion handler for block_read_full_page() - pages
- * which come unlocked at the end of I/O.
- */
-static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
+void end_buffer_page_read(struct buffer_head *bh)
 {
 	unsigned long flags;
 	struct buffer_head *first;
@@ -257,17 +254,7 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
 	struct page *page;
 	int page_uptodate = 1;
 
-	BUG_ON(!buffer_async_read(bh));
-
 	page = bh->b_page;
-	if (uptodate) {
-		set_buffer_uptodate(bh);
-	} else {
-		clear_buffer_uptodate(bh);
-		buffer_io_error(bh, ", async page read");
-		SetPageError(page);
-	}
-
 	/*
 	 * Be _very_ careful from here on. Bad things can happen if
 	 * two buffer heads end IO at almost the same time and both
@@ -305,6 +292,45 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
 	local_irq_restore(flags);
 	return;
 }
+EXPORT_SYMBOL(end_buffer_page_read);
+
+/*
+ * I/O completion handler for block_read_full_page() - pages
+ * which come unlocked at the end of I/O.
+ */
+static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
+{
+	struct page *page;
+
+	BUG_ON(!buffer_async_read(bh));
+
+	if (uptodate && bh->b_private) {
+		struct post_read_ctx *ctx = bh->b_private;
+
+		post_read_processing(ctx);
+		return;
+	}
+
+	if (bh->b_private) {
+		struct post_read_ctx *ctx = bh->b_private;
+
+		WARN_ON(uptodate);
+		put_post_read_ctx(ctx);
+	}
+
+	page = bh->b_page;
+	if (uptodate) {
+		set_buffer_uptodate(bh);
+	} else {
+		clear_buffer_uptodate(bh);
+		buffer_io_error(bh, ", async page read");
+		SetPageError(page);
+	}
+
+	end_buffer_page_read(bh);
+
+	return;
+}
 
 /*
  * Completion handler for block_write_full_page() - pages which are unlocked
@@ -2220,7 +2246,11 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
 {
 	struct inode *inode = page->mapping->host;
 	sector_t iblock, lblock;
-	struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
+	struct buffer_head *bh, *head;
+	struct {
+		sector_t blk_nr;
+		struct buffer_head *bh;
+	} arr[MAX_BUF_PER_PAGE];
 	unsigned int blocksize, bbits;
 	int nr, i;
 	int fully_mapped = 1;
@@ -2262,7 +2292,9 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
 			if (buffer_uptodate(bh))
 				continue;
 		}
-		arr[nr++] = bh;
+		arr[nr].blk_nr = iblock;
+		arr[nr].bh = bh;
+		++nr;
 	} while (i++, iblock++, (bh = bh->b_this_page) != head);
 
 	if (fully_mapped)
@@ -2281,7 +2313,7 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
 
 	/* Stage two: lock the buffers */
 	for (i = 0; i < nr; i++) {
-		bh = arr[i];
+		bh = arr[i].bh;
 		lock_buffer(bh);
 		mark_buffer_async_read(bh);
 	}
@@ -2292,11 +2324,19 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
 	 * the underlying blockdev brought it uptodate (the sct fix).
 	 */
 	for (i = 0; i < nr; i++) {
-		bh = arr[i];
-		if (buffer_uptodate(bh))
+		struct post_read_ctx *ctx;
+
+		bh = arr[i].bh;
+		if (buffer_uptodate(bh)) {
 			end_buffer_async_read(bh, 1);
-		else
+		} else {
+			ctx = get_post_read_ctx(inode, NULL, bh, arr[i].blk_nr);
+			if (WARN_ON(IS_ERR(ctx))) {
+				end_buffer_async_read(bh, 0);
+				continue;
+			}
 			submit_bh(REQ_OP_READ, 0, bh);
+		}
 	}
 	return 0;
 }
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index bab48dfa3765..83de1e46f546 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -24,44 +24,60 @@
 #include <linux/module.h>
 #include <linux/bio.h>
 #include <linux/namei.h>
+#include <linux/buffer_head.h>
 #include <linux/post_read_process.h>
 
 #include "fscrypt_private.h"
 
-static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
+static void fscrypt_decrypt(struct bio *bio, struct buffer_head *bh)
 {
+	struct inode *inode;
+	struct page *page;
 	struct bio_vec *bv;
+	sector_t blk_nr;
+	int ret;
 	int i;
 	struct bvec_iter_all iter_all;
 
-	bio_for_each_segment_all(bv, bio, i, iter_all) {
-		struct page *page = bv->bv_page;
-		int ret = fscrypt_decrypt_page(page->mapping->host, page,
-				PAGE_SIZE, 0, page->index);
+	WARN_ON(!bh && !bio);
 
+	if (bh) {
+		page = bh->b_page;
+		inode = page->mapping->host;
+
+		blk_nr = page->index << (PAGE_SHIFT - inode->i_blkbits);
+		blk_nr += (bh_offset(bh) >> inode->i_blkbits);
+
+		ret = fscrypt_decrypt_page(inode, page, i_blocksize(inode),
+					bh_offset(bh), blk_nr);
 		if (ret) {
 			WARN_ON_ONCE(1);
 			SetPageError(page);
-		} else if (done) {
-			SetPageUptodate(page);
 		}
-		if (done)
-			unlock_page(page);
+	} else if (bio) {
+		bio_for_each_segment_all(bv, bio, i, iter_all) {
+			struct page *page = bv->bv_page;
+			struct inode *inode = page->mapping->host;
+			const unsigned int blkbits = inode->i_blkbits;
+			u64 page_blk = page->index << (PAGE_SHIFT - blkbits);
+			u64 blk = page_blk + (bv->bv_offset >> blkbits);
+			int ret = fscrypt_decrypt_page(page->mapping->host,
+						page, bv->bv_len,
+						bv->bv_offset, blk);
+			if (ret) {
+				WARN_ON_ONCE(1);
+				SetPageError(page);
+			}
+		}
 	}
 }
 
-void fscrypt_decrypt_bio(struct bio *bio)
-{
-	__fscrypt_decrypt_bio(bio, false);
-}
-EXPORT_SYMBOL(fscrypt_decrypt_bio);
-
 void fscrypt_decrypt_work(struct work_struct *work)
 {
 	struct post_read_ctx *ctx =
 		container_of(work, struct post_read_ctx, work);
 
-	fscrypt_decrypt_bio(ctx->bio);
+	fscrypt_decrypt(ctx->bio, ctx->bh);
 
 	post_read_processing(ctx);
 }
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index ffa9302a7351..4f0d832cae71 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -305,11 +305,26 @@ EXPORT_SYMBOL(fscrypt_encrypt_page);
 int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
 			unsigned int len, unsigned int offs, u64 lblk_num)
 {
+	int i, page_nr_blks;
+	int err = 0;
+
 	if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES))
 		BUG_ON(!PageLocked(page));
 
-	return fscrypt_do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page,
-				      len, offs, GFP_NOFS);
+	page_nr_blks = len >> inode->i_blkbits;
+
+	for (i = 0; i < page_nr_blks; i++) {
+		err = fscrypt_do_page_crypto(inode, FS_DECRYPT, lblk_num,
+					page, page, i_blocksize(inode), offs,
+					GFP_NOFS);
+		if (err)
+			break;
+
+		++lblk_num;
+		offs += i_blocksize(inode);
+	}
+
+	return err;
 }
 EXPORT_SYMBOL(fscrypt_decrypt_page);
 
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index f00f018bed27..933b28d5809e 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -527,7 +527,7 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 	bio_set_op_attrs(bio, REQ_OP_READ, op_flag);
 
 #if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
-	ctx = get_post_read_ctx(inode, bio, first_idx);
+	ctx = get_post_read_ctx(inode, bio, NULL, first_idx);
 	if (IS_ERR(ctx)) {
 		bio_put(bio);
 		return (struct bio *)ctx;
diff --git a/fs/mpage.c b/fs/mpage.c
index 3c0e484a1d2f..4f672889a947 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -344,7 +344,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 			goto confused;
 
 #if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
-		ctx = get_post_read_ctx(inode, args->bio, page->index);
+		ctx = get_post_read_ctx(inode, args->bio, NULL, page->index);
 		if (IS_ERR(ctx)) {
 			bio_put(args->bio);
 			args->bio = NULL;
diff --git a/fs/post_read_process.c b/fs/post_read_process.c
index f0ec1957a8b3..b633f3dda4bd 100644
--- a/fs/post_read_process.c
+++ b/fs/post_read_process.c
@@ -8,6 +8,7 @@
 #include <linux/mm.h>
 #include <linux/pagemap.h>
 #include <linux/bio.h>
+#include <linux/buffer_head.h>
 #include <linux/fscrypt.h>
 #include <linux/fsverity.h>
 #include <linux/post_read_process.h>
@@ -24,26 +25,41 @@ enum post_read_step {
 	STEP_VERITY,
 };
 
-void end_post_read_processing(struct bio *bio)
+void end_post_read_processing(struct bio *bio, struct buffer_head *bh)
 {
+	struct post_read_ctx *ctx;
 	struct page *page;
 	struct bio_vec *bv;
 	int i;
 	struct bvec_iter_all iter_all;
 
-	bio_for_each_segment_all(bv, bio, i, iter_all) {
-		page = bv->bv_page;
+	if (bh) {
+		if (!PageError(bh->b_page))
+			set_buffer_uptodate(bh);
 
-		BUG_ON(bio->bi_status);
+		ctx = bh->b_private;
 
-		if (!PageError(page))
-			SetPageUptodate(page);
+		end_buffer_page_read(bh);
 
-		unlock_page(page);
+		put_post_read_ctx(ctx);
+	} else if (bio) {
+		bio_for_each_segment_all(bv, bio, i, iter_all) {
+			page = bv->bv_page;
+
+			WARN_ON(bio->bi_status);
+
+			if (!PageError(page))
+				SetPageUptodate(page);
+
+			unlock_page(page);
+		}
+		WARN_ON(!bio->bi_private);
+
+		ctx = bio->bi_private;
+		put_post_read_ctx(ctx);
+
+		bio_put(bio);
 	}
-	if (bio->bi_private)
-		put_post_read_ctx(bio->bi_private);
-	bio_put(bio);
 }
 EXPORT_SYMBOL(end_post_read_processing);
 
@@ -70,18 +86,21 @@ void post_read_processing(struct post_read_ctx *ctx)
 		ctx->cur_step++;
 		/* fall-through */
 	default:
-		end_post_read_processing(ctx->bio);
+		end_post_read_processing(ctx->bio, ctx->bh);
 	}
 }
 EXPORT_SYMBOL(post_read_processing);
 
 struct post_read_ctx *get_post_read_ctx(struct inode *inode,
 					struct bio *bio,
+					struct buffer_head *bh,
 					pgoff_t index)
 {
 	unsigned int post_read_steps = 0;
 	struct post_read_ctx *ctx = NULL;
 
+	WARN_ON(!bh && !bio);
+
 	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
 		post_read_steps |= 1 << STEP_DECRYPT;
 #ifdef CONFIG_FS_VERITY
@@ -95,11 +114,15 @@ struct post_read_ctx *get_post_read_ctx(struct inode *inode,
 		ctx = mempool_alloc(post_read_ctx_pool, GFP_NOFS);
 		if (!ctx)
 			return ERR_PTR(-ENOMEM);
+		ctx->bh = bh;
 		ctx->bio = bio;
 		ctx->inode = inode;
 		ctx->enabled_steps = post_read_steps;
 		ctx->cur_step = STEP_INITIAL;
-		bio->bi_private = ctx;
+		if (bio)
+			bio->bi_private = ctx;
+		else if (bh)
+			bh->b_private = ctx;
 	}
 	return ctx;
 }
@@ -111,12 +134,6 @@ void put_post_read_ctx(struct post_read_ctx *ctx)
 }
 EXPORT_SYMBOL(put_post_read_ctx);
 
-bool post_read_required(struct bio *bio)
-{
-	return bio->bi_private && !bio->bi_status;
-}
-EXPORT_SYMBOL(post_read_required);
-
 static int __init init_post_read_processing(void)
 {
 	post_read_ctx_cache = KMEM_CACHE(post_read_ctx, 0);
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 7b73ef7f902d..782ed6350dfc 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -165,6 +165,7 @@ void create_empty_buffers(struct page *, unsigned long,
 void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
 void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
 void end_buffer_async_write(struct buffer_head *bh, int uptodate);
+void end_buffer_page_read(struct buffer_head *bh);
 
 /* Things to do with buffers at mapping->private_list */
 void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode);
diff --git a/include/linux/post_read_process.h b/include/linux/post_read_process.h
index 523bdecf9252..cb3e676aea64 100644
--- a/include/linux/post_read_process.h
+++ b/include/linux/post_read_process.h
@@ -3,6 +3,7 @@
 #define _POST_READ_PROCESS_H
 
 struct post_read_ctx {
+	struct buffer_head *bh;
 	struct bio *bio;
 	struct inode *inode;
 	struct work_struct work;
@@ -10,12 +11,12 @@ struct post_read_ctx {
 	unsigned int enabled_steps;
 };
 
-void end_post_read_processing(struct bio *bio);
+void end_post_read_processing(struct bio *bio, struct buffer_head *bh);
 void post_read_processing(struct post_read_ctx *ctx);
 struct post_read_ctx *get_post_read_ctx(struct inode *inode,
 					struct bio *bio,
+					struct buffer_head *bh,
 					pgoff_t index);
 void put_post_read_ctx(struct post_read_ctx *ctx);
-bool post_read_required(struct bio *bio);
 
 #endif	/* _POST_READ_PROCESS_H */
-- 
2.19.1

[RFC PATCH 09/14] ext4: Decrypt all boundary blocks when doing buffered write

[Chandan Rajendra]

With subpage sized blocks, ext4_block_write_begin() can have up to two
blocks to decrypt. Hence this commit invokes fscrypt_decrypt_page() for
each of those blocks.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/ext4/inode.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1327e04334df..51744a3c3964 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1156,12 +1156,14 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
 	unsigned to = from + len;
 	struct inode *inode = page->mapping->host;
 	unsigned block_start, block_end;
-	sector_t block;
+	sector_t block, page_blk_nr;
 	int err = 0;
 	unsigned blocksize = inode->i_sb->s_blocksize;
 	unsigned bbits;
-	struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
+	struct buffer_head *bh, *head, *wait[2];
+	int nr_wait = 0;
 	bool decrypt = false;
+	int i;
 
 	BUG_ON(!PageLocked(page));
 	BUG_ON(from > PAGE_SIZE);
@@ -1213,25 +1215,36 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
 		    !buffer_unwritten(bh) &&
 		    (block_start < from || block_end > to)) {
 			ll_rw_block(REQ_OP_READ, 0, 1, &bh);
-			*wait_bh++ = bh;
+			wait[nr_wait++] = bh;
 			decrypt = IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
 		}
 	}
 	/*
 	 * If we issued read requests, let them complete.
 	 */
-	while (wait_bh > wait) {
-		wait_on_buffer(*--wait_bh);
-		if (!buffer_uptodate(*wait_bh))
+	for (i = 0; i < nr_wait; i++) {
+		wait_on_buffer(wait[i]);
+		if (!buffer_uptodate(wait[i]))
 			err = -EIO;
 	}
 	if (unlikely(err)) {
 		page_zero_new_buffers(page, from, to);
 	} else if (decrypt) {
-		err = fscrypt_decrypt_page(page->mapping->host, page,
-				PAGE_SIZE, 0, page->index);
-		if (err)
-			clear_buffer_uptodate(*wait_bh);
+		page_blk_nr = (sector_t)page->index << (PAGE_SHIFT - bbits);
+
+		for (i = 0; i < nr_wait; i++) {
+			int err2;
+
+			block = page_blk_nr + (bh_offset(wait[i]) >> bbits);
+			err2 = fscrypt_decrypt_page(page->mapping->host, page,
+						wait[i]->b_size,
+						bh_offset(wait[i]),
+						block);
+			if (err2) {
+				clear_buffer_uptodate(wait[i]);
+				err = err2;
+			}
+		}
 	}
 
 	return err;
-- 
2.19.1

[RFC PATCH 10/14] ext4: Decrypt the block that needs to be partially zeroed

[Chandan Rajendra]

__ext4_block_zero_page_range decrypts the entire page. This commit
decrypts the block to be partially zeroed instead of the whole page.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/ext4/inode.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 51744a3c3964..ade1816697a8 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4080,9 +4080,10 @@ static int __ext4_block_zero_page_range(handle_t *handle,
 		if (S_ISREG(inode->i_mode) && IS_ENCRYPTED(inode)) {
 			/* We expect the key to be set. */
 			BUG_ON(!fscrypt_has_encryption_key(inode));
-			BUG_ON(blocksize != PAGE_SIZE);
 			WARN_ON_ONCE(fscrypt_decrypt_page(page->mapping->host,
-						page, PAGE_SIZE, 0, page->index));
+							page, blocksize,
+							round_down(offset, blocksize),
+							iblock));
 		}
 	}
 	if (ext4_should_journal_data(inode)) {
-- 
2.19.1

[RFC PATCH 11/14] fscrypt_encrypt_page: Loop across all blocks mapped by a page range

[Chandan Rajendra]

For subpage-sized blocks, this commit now encrypts all blocks mapped by
a page range.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/crypto/crypto.c | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 4f0d832cae71..84d11d8eb7e3 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -242,18 +242,26 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
 {
 	struct fscrypt_ctx *ctx;
 	struct page *ciphertext_page = page;
+	int i, page_nr_blks;
 	int err;
 
 	BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0);
 
+	page_nr_blks = len >> inode->i_blkbits;
+
 	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);
-
+		for (i = 0; i < page_nr_blks; i++) {
+			err = fscrypt_do_page_crypto(inode, FS_ENCRYPT,
+						lblk_num, page,
+						ciphertext_page,
+						i_blocksize(inode), offs,
+						gfp_flags);
+			if (err)
+				return ERR_PTR(err);
+			++lblk_num;
+			offs += i_blocksize(inode);
+		}
 		return ciphertext_page;
 	}
 
@@ -269,12 +277,17 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
 		goto errout;
 
 	ctx->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;
+
+	for (i = 0; i < page_nr_blks; i++) {
+		err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num,
+					page, ciphertext_page, i_blocksize(inode), offs,
+					gfp_flags);
+		if (err) {
+			ciphertext_page = ERR_PTR(err);
+			goto errout;
+		}
+		++lblk_num;
+		offs += i_blocksize(inode);
 	}
 	SetPagePrivate(ciphertext_page);
 	set_page_private(ciphertext_page, (unsigned long)ctx);
-- 
2.19.1

[RFC PATCH 12/14] ext4: Compute logical block and the page range to be encrypted

[Chandan Rajendra]

For subpage-sized blocks, the initial logical block number mapped by a
page can be different from page->index. Hence this commit adds code to
compute the first logical block mapped by the page and also the page
range to be encrypted.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/ext4/page-io.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 3e9298e6a705..75485ee9e800 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -418,6 +418,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
 {
 	struct page *data_page = NULL;
 	struct inode *inode = page->mapping->host;
+	u64 page_blk;
 	unsigned block_start;
 	struct buffer_head *bh, *head;
 	int ret = 0;
@@ -478,10 +479,14 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
 
 	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) && nr_to_submit) {
 		gfp_t gfp_flags = GFP_NOFS;
+		unsigned int page_bytes;
+
+		page_bytes = round_up(len, i_blocksize(inode));
+		page_blk = page->index << (PAGE_SHIFT - inode->i_blkbits);
 
 	retry_encrypt:
-		data_page = fscrypt_encrypt_page(inode, page, PAGE_SIZE, 0,
-						page->index, gfp_flags);
+		data_page = fscrypt_encrypt_page(inode, page, page_bytes, 0,
+						page_blk, gfp_flags);
 		if (IS_ERR(data_page)) {
 			ret = PTR_ERR(data_page);
 			if (ret == -ENOMEM && wbc->sync_mode == WB_SYNC_ALL) {
-- 
2.19.1

[RFC PATCH 13/14] fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page

[Chandan Rajendra]

For subpage-sized blocks, this commit adds code to encrypt all zeroed
out blocks mapped by a page.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/crypto/bio.c | 40 ++++++++++++++++++----------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index 83de1e46f546..2c6ce4218fd4 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -106,29 +106,23 @@ 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;
+	u64 total_bytes, page_bytes;
 	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);
+	total_bytes = len << inode->i_blkbits;
 
-	ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
-	if (IS_ERR(ciphertext_page)) {
-		err = PTR_ERR(ciphertext_page);
-		goto errout;
-	}
+	while (total_bytes) {
+		page_bytes = min_t(u64, total_bytes, PAGE_SIZE);
 
-	while (len--) {
-		err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
-					     ZERO_PAGE(0), ciphertext_page,
-					     PAGE_SIZE, 0, GFP_NOFS);
-		if (err)
+		ciphertext_page = fscrypt_encrypt_page(inode, ZERO_PAGE(0),
+						page_bytes, 0, lblk, GFP_NOFS);
+		if (IS_ERR(ciphertext_page)) {
+			err = PTR_ERR(ciphertext_page);
+			ciphertext_page = NULL;
 			goto errout;
+		}
 
 		bio = bio_alloc(GFP_NOWAIT, 1);
 		if (!bio) {
@@ -139,9 +133,8 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 		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) {
+		ret = bio_add_page(bio, ciphertext_page, page_bytes, 0);
+		if (ret != page_bytes) {
 			/* should never happen! */
 			WARN_ON(1);
 			bio_put(bio);
@@ -154,12 +147,15 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 		bio_put(bio);
 		if (err)
 			goto errout;
-		lblk++;
-		pblk++;
+
+		lblk += page_bytes >> inode->i_blkbits;
+		pblk += page_bytes >> inode->i_blkbits;
+		total_bytes -= page_bytes;
 	}
 	err = 0;
 errout:
-	fscrypt_release_ctx(ctx);
+	if (!IS_ERR_OR_NULL(ciphertext_page))
+		fscrypt_restore_control_page(ciphertext_page);
 	return err;
 }
 EXPORT_SYMBOL(fscrypt_zeroout_range);
-- 
2.19.1

[RFC PATCH 14/14] ext4: Enable encryption for subpage-sized blocks

[Chandan Rajendra]

Now that we have the code to support encryption for subpage-sized
blocks, this commit removes the conditional check in filesystem mount
code.

The commit also changes the support statement in
Documentation/filesystems/fscrypt.rst to reflect the fact that
encryption of filesystems with blocksize less than page size now works.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 Documentation/filesystems/fscrypt.rst | 4 ++--
 fs/ext4/super.c                       | 7 -------
 2 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
index 08c23b60e016..ff2fea121da9 100644
--- a/Documentation/filesystems/fscrypt.rst
+++ b/Documentation/filesystems/fscrypt.rst
@@ -213,8 +213,8 @@ Contents encryption
 -------------------
 
 For file contents, each filesystem block is encrypted independently.
-Currently, only the case where the filesystem block size is equal to
-the system's page size (usually 4096 bytes) is supported.
+Starting from Linux kernel 5.3, 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:
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index cadf50f9503f..549e5bec1aba 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4433,13 +4433,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		}
 	}
 
-	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
-	    (blocksize != PAGE_SIZE)) {
-		ext4_msg(sb, KERN_ERR,
-			 "Unsupported blocksize for fs encryption");
-		goto failed_mount_wq;
-	}
-
 	if (DUMMY_ENCRYPTION_ENABLED(sbi) && !sb_rdonly(sb) &&
 	    !ext4_has_feature_encrypt(sb)) {
 		ext4_set_feature_encrypt(sb);
-- 
2.19.1