[PATCH v2 0/2] fscrypt / f2fs: prepare I/O path for fs-verity

[PATCH v2 0/2] fscrypt / f2fs: prepare I/O path for fs-verity

[Eric Biggers via Linux-f2fs-devel]

Hello,

These two patches restructure f2fs's read path to allow the data to go
through multiple postprocessing steps, rather than just decryption as is
implemented currently.  This is mainly in preparation for doing
authenticity verification of data via fs-verity, though this change
might also be useful for other future f2fs features, e.g. compression.

These patches don't yet add the fs-verity work, however, as it depends
on the rest of the fs-verity patchset.  I'm planning to send the full
patchset out as an RFC, but some parts need further investigation first.
(The work-in-progress version can be found at
 git://git.kernel.org/pub/scm/linux/kernel/git/mhalcrow/linux.git,
 branch "fs-verity-dev".)

Changed since v1:
	
	- Define NUM_PREALLOC_POST_READ_CTXS

Eric Biggers (2):
  fscrypt: allow synchronous bio decryption
  f2fs: refactor read path to allow multiple postprocessing steps

 fs/crypto/bio.c                 |  35 ++++---
 fs/crypto/crypto.c              |   8 +-
 fs/crypto/fscrypt_private.h     |   1 -
 fs/ext4/readpage.c              |   2 +-
 fs/f2fs/data.c                  | 166 ++++++++++++++++++++++++--------
 fs/f2fs/f2fs.h                  |  12 ++-
 fs/f2fs/file.c                  |   4 +-
 fs/f2fs/gc.c                    |   6 +-
 fs/f2fs/inline.c                |   2 +-
 fs/f2fs/super.c                 |   6 ++
 include/linux/fscrypt_notsupp.h |  13 ++-
 include/linux/fscrypt_supp.h    |   5 +-
 12 files changed, 191 insertions(+), 69 deletions(-)

-- 
2.17.0.484.g0c8726318c-goog


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[PATCH v2 1/2] fscrypt: allow synchronous bio decryption

[Eric Biggers via Linux-f2fs-devel]

Currently, fscrypt provides fscrypt_decrypt_bio_pages() which decrypts a
bio's pages asynchronously, then unlocks them afterwards.  But, this
assumes that decryption is the last "postprocessing step" for the bio,
so it's incompatible with additional postprocessing steps such as
authenticity verification after decryption.

Therefore, rename the existing fscrypt_decrypt_bio_pages() to
fscrypt_enqueue_decrypt_bio().  Then, add fscrypt_decrypt_bio() which
decrypts the pages in the bio synchronously without unlocking the pages,
nor setting them Uptodate; and add fscrypt_enqueue_decrypt_work(), which
enqueues work on the fscrypt_read_workqueue.  The new functions will be
used by filesystems that support both fscrypt and fs-verity.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/crypto/bio.c                 | 35 +++++++++++++++++++++------------
 fs/crypto/crypto.c              |  8 +++++++-
 fs/crypto/fscrypt_private.h     |  1 -
 fs/ext4/readpage.c              |  2 +-
 fs/f2fs/data.c                  |  2 +-
 include/linux/fscrypt_notsupp.h | 13 +++++++++---
 include/linux/fscrypt_supp.h    |  5 ++++-
 7 files changed, 45 insertions(+), 21 deletions(-)

diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index 0d5e6a569d58..0959044c5cee 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -26,15 +26,8 @@
 #include <linux/namei.h>
 #include "fscrypt_private.h"
 
-/*
- * Call fscrypt_decrypt_page on every single page, reusing the encryption
- * context.
- */
-static void completion_pages(struct work_struct *work)
+static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
 {
-	struct fscrypt_ctx *ctx =
-		container_of(work, struct fscrypt_ctx, r.work);
-	struct bio *bio = ctx->r.bio;
 	struct bio_vec *bv;
 	int i;
 
@@ -46,22 +39,38 @@ static void completion_pages(struct work_struct *work)
 		if (ret) {
 			WARN_ON_ONCE(1);
 			SetPageError(page);
-		} else {
+		} else if (done) {
 			SetPageUptodate(page);
 		}
-		unlock_page(page);
+		if (done)
+			unlock_page(page);
 	}
+}
+
+void fscrypt_decrypt_bio(struct bio *bio)
+{
+	__fscrypt_decrypt_bio(bio, false);
+}
+EXPORT_SYMBOL(fscrypt_decrypt_bio);
+
+static void completion_pages(struct work_struct *work)
+{
+	struct fscrypt_ctx *ctx =
+		container_of(work, struct fscrypt_ctx, r.work);
+	struct bio *bio = ctx->r.bio;
+
+	__fscrypt_decrypt_bio(bio, true);
 	fscrypt_release_ctx(ctx);
 	bio_put(bio);
 }
 
-void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
+void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, struct bio *bio)
 {
 	INIT_WORK(&ctx->r.work, completion_pages);
 	ctx->r.bio = bio;
-	queue_work(fscrypt_read_workqueue, &ctx->r.work);
+	fscrypt_enqueue_decrypt_work(&ctx->r.work);
 }
-EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
+EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio);
 
 void fscrypt_pullback_bio_page(struct page **page, bool restore)
 {
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index ce654526c0fb..0758d32ad01b 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -45,12 +45,18 @@ static mempool_t *fscrypt_bounce_page_pool = NULL;
 static LIST_HEAD(fscrypt_free_ctxs);
 static DEFINE_SPINLOCK(fscrypt_ctx_lock);
 
-struct workqueue_struct *fscrypt_read_workqueue;
+static struct workqueue_struct *fscrypt_read_workqueue;
 static DEFINE_MUTEX(fscrypt_init_mutex);
 
 static struct kmem_cache *fscrypt_ctx_cachep;
 struct kmem_cache *fscrypt_info_cachep;
 
+void fscrypt_enqueue_decrypt_work(struct work_struct *work)
+{
+	queue_work(fscrypt_read_workqueue, work);
+}
+EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work);
+
 /**
  * fscrypt_release_ctx() - Releases an encryption context
  * @ctx: The encryption context to release.
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index ad6722bae8b7..4012558f6115 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -97,7 +97,6 @@ static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
 /* crypto.c */
 extern struct kmem_cache *fscrypt_info_cachep;
 extern int fscrypt_initialize(unsigned int cop_flags);
-extern struct workqueue_struct *fscrypt_read_workqueue;
 extern int fscrypt_do_page_crypto(const struct inode *inode,
 				  fscrypt_direction_t rw, u64 lblk_num,
 				  struct page *src_page,
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index 9ffa6fad18db..19b87a8de6ff 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -77,7 +77,7 @@ static void mpage_end_io(struct bio *bio)
 		if (bio->bi_status) {
 			fscrypt_release_ctx(bio->bi_private);
 		} else {
-			fscrypt_decrypt_bio_pages(bio->bi_private, bio);
+			fscrypt_enqueue_decrypt_bio(bio->bi_private, bio);
 			return;
 		}
 	}
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 02237d4d91f5..39225519de1c 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -66,7 +66,7 @@ static void f2fs_read_end_io(struct bio *bio)
 		if (bio->bi_status) {
 			fscrypt_release_ctx(bio->bi_private);
 		} else {
-			fscrypt_decrypt_bio_pages(bio->bi_private, bio);
+			fscrypt_enqueue_decrypt_bio(bio->bi_private, bio);
 			return;
 		}
 	}
diff --git a/include/linux/fscrypt_notsupp.h b/include/linux/fscrypt_notsupp.h
index 44b50c04bae9..9770be37c9d4 100644
--- a/include/linux/fscrypt_notsupp.h
+++ b/include/linux/fscrypt_notsupp.h
@@ -25,6 +25,10 @@ static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
 }
 
 /* crypto.c */
+static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
+{
+}
+
 static inline struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode,
 						  gfp_t gfp_flags)
 {
@@ -160,10 +164,13 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
 }
 
 /* bio.c */
-static inline void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx,
-					     struct bio *bio)
+static inline void fscrypt_decrypt_bio(struct bio *bio)
+{
+}
+
+static inline void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx,
+					       struct bio *bio)
 {
-	return;
 }
 
 static inline void fscrypt_pullback_bio_page(struct page **page, bool restore)
diff --git a/include/linux/fscrypt_supp.h b/include/linux/fscrypt_supp.h
index 477a7a6504d2..2c9a86ac5e83 100644
--- a/include/linux/fscrypt_supp.h
+++ b/include/linux/fscrypt_supp.h
@@ -59,6 +59,7 @@ static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
 }
 
 /* crypto.c */
+extern void fscrypt_enqueue_decrypt_work(struct work_struct *);
 extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t);
 extern void fscrypt_release_ctx(struct fscrypt_ctx *);
 extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
@@ -188,7 +189,9 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
 }
 
 /* bio.c */
-extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
+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);
-- 
2.17.0.484.g0c8726318c-goog


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Re: [PATCH v2 1/2] fscrypt: allow synchronous bio decryption

[Jaegeuk Kim]

Queued in f2fs/dev.
Thanks,

On 04/18, Eric Biggers wrote:
> Currently, fscrypt provides fscrypt_decrypt_bio_pages() which decrypts a
> bio's pages asynchronously, then unlocks them afterwards.  But, this
> assumes that decryption is the last "postprocessing step" for the bio,
> so it's incompatible with additional postprocessing steps such as
> authenticity verification after decryption.
> 
> Therefore, rename the existing fscrypt_decrypt_bio_pages() to
> fscrypt_enqueue_decrypt_bio().  Then, add fscrypt_decrypt_bio() which
> decrypts the pages in the bio synchronously without unlocking the pages,
> nor setting them Uptodate; and add fscrypt_enqueue_decrypt_work(), which
> enqueues work on the fscrypt_read_workqueue.  The new functions will be
> used by filesystems that support both fscrypt and fs-verity.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
>  fs/crypto/bio.c                 | 35 +++++++++++++++++++++------------
>  fs/crypto/crypto.c              |  8 +++++++-
>  fs/crypto/fscrypt_private.h     |  1 -
>  fs/ext4/readpage.c              |  2 +-
>  fs/f2fs/data.c                  |  2 +-
>  include/linux/fscrypt_notsupp.h | 13 +++++++++---
>  include/linux/fscrypt_supp.h    |  5 ++++-
>  7 files changed, 45 insertions(+), 21 deletions(-)
> 
> diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
> index 0d5e6a569d58..0959044c5cee 100644
> --- a/fs/crypto/bio.c
> +++ b/fs/crypto/bio.c
> @@ -26,15 +26,8 @@
>  #include <linux/namei.h>
>  #include "fscrypt_private.h"
>  
> -/*
> - * Call fscrypt_decrypt_page on every single page, reusing the encryption
> - * context.
> - */
> -static void completion_pages(struct work_struct *work)
> +static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
>  {
> -	struct fscrypt_ctx *ctx =
> -		container_of(work, struct fscrypt_ctx, r.work);
> -	struct bio *bio = ctx->r.bio;
>  	struct bio_vec *bv;
>  	int i;
>  
> @@ -46,22 +39,38 @@ static void completion_pages(struct work_struct *work)
>  		if (ret) {
>  			WARN_ON_ONCE(1);
>  			SetPageError(page);
> -		} else {
> +		} else if (done) {
>  			SetPageUptodate(page);
>  		}
> -		unlock_page(page);
> +		if (done)
> +			unlock_page(page);
>  	}
> +}
> +
> +void fscrypt_decrypt_bio(struct bio *bio)
> +{
> +	__fscrypt_decrypt_bio(bio, false);
> +}
> +EXPORT_SYMBOL(fscrypt_decrypt_bio);
> +
> +static void completion_pages(struct work_struct *work)
> +{
> +	struct fscrypt_ctx *ctx =
> +		container_of(work, struct fscrypt_ctx, r.work);
> +	struct bio *bio = ctx->r.bio;
> +
> +	__fscrypt_decrypt_bio(bio, true);
>  	fscrypt_release_ctx(ctx);
>  	bio_put(bio);
>  }
>  
> -void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
> +void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, struct bio *bio)
>  {
>  	INIT_WORK(&ctx->r.work, completion_pages);
>  	ctx->r.bio = bio;
> -	queue_work(fscrypt_read_workqueue, &ctx->r.work);
> +	fscrypt_enqueue_decrypt_work(&ctx->r.work);
>  }
> -EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
> +EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio);
>  
>  void fscrypt_pullback_bio_page(struct page **page, bool restore)
>  {
> diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
> index ce654526c0fb..0758d32ad01b 100644
> --- a/fs/crypto/crypto.c
> +++ b/fs/crypto/crypto.c
> @@ -45,12 +45,18 @@ static mempool_t *fscrypt_bounce_page_pool = NULL;
>  static LIST_HEAD(fscrypt_free_ctxs);
>  static DEFINE_SPINLOCK(fscrypt_ctx_lock);
>  
> -struct workqueue_struct *fscrypt_read_workqueue;
> +static struct workqueue_struct *fscrypt_read_workqueue;
>  static DEFINE_MUTEX(fscrypt_init_mutex);
>  
>  static struct kmem_cache *fscrypt_ctx_cachep;
>  struct kmem_cache *fscrypt_info_cachep;
>  
> +void fscrypt_enqueue_decrypt_work(struct work_struct *work)
> +{
> +	queue_work(fscrypt_read_workqueue, work);
> +}
> +EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work);
> +
>  /**
>   * fscrypt_release_ctx() - Releases an encryption context
>   * @ctx: The encryption context to release.
> diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
> index ad6722bae8b7..4012558f6115 100644
> --- a/fs/crypto/fscrypt_private.h
> +++ b/fs/crypto/fscrypt_private.h
> @@ -97,7 +97,6 @@ static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
>  /* crypto.c */
>  extern struct kmem_cache *fscrypt_info_cachep;
>  extern int fscrypt_initialize(unsigned int cop_flags);
> -extern struct workqueue_struct *fscrypt_read_workqueue;
>  extern int fscrypt_do_page_crypto(const struct inode *inode,
>  				  fscrypt_direction_t rw, u64 lblk_num,
>  				  struct page *src_page,
> diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
> index 9ffa6fad18db..19b87a8de6ff 100644
> --- a/fs/ext4/readpage.c
> +++ b/fs/ext4/readpage.c
> @@ -77,7 +77,7 @@ static void mpage_end_io(struct bio *bio)
>  		if (bio->bi_status) {
>  			fscrypt_release_ctx(bio->bi_private);
>  		} else {
> -			fscrypt_decrypt_bio_pages(bio->bi_private, bio);
> +			fscrypt_enqueue_decrypt_bio(bio->bi_private, bio);
>  			return;
>  		}
>  	}
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 02237d4d91f5..39225519de1c 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -66,7 +66,7 @@ static void f2fs_read_end_io(struct bio *bio)
>  		if (bio->bi_status) {
>  			fscrypt_release_ctx(bio->bi_private);
>  		} else {
> -			fscrypt_decrypt_bio_pages(bio->bi_private, bio);
> +			fscrypt_enqueue_decrypt_bio(bio->bi_private, bio);
>  			return;
>  		}
>  	}
> diff --git a/include/linux/fscrypt_notsupp.h b/include/linux/fscrypt_notsupp.h
> index 44b50c04bae9..9770be37c9d4 100644
> --- a/include/linux/fscrypt_notsupp.h
> +++ b/include/linux/fscrypt_notsupp.h
> @@ -25,6 +25,10 @@ static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
>  }
>  
>  /* crypto.c */
> +static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
> +{
> +}
> +
>  static inline struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode,
>  						  gfp_t gfp_flags)
>  {
> @@ -160,10 +164,13 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
>  }
>  
>  /* bio.c */
> -static inline void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx,
> -					     struct bio *bio)
> +static inline void fscrypt_decrypt_bio(struct bio *bio)
> +{
> +}
> +
> +static inline void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx,
> +					       struct bio *bio)
>  {
> -	return;
>  }
>  
>  static inline void fscrypt_pullback_bio_page(struct page **page, bool restore)
> diff --git a/include/linux/fscrypt_supp.h b/include/linux/fscrypt_supp.h
> index 477a7a6504d2..2c9a86ac5e83 100644
> --- a/include/linux/fscrypt_supp.h
> +++ b/include/linux/fscrypt_supp.h
> @@ -59,6 +59,7 @@ static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
>  }
>  
>  /* crypto.c */
> +extern void fscrypt_enqueue_decrypt_work(struct work_struct *);
>  extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t);
>  extern void fscrypt_release_ctx(struct fscrypt_ctx *);
>  extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
> @@ -188,7 +189,9 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
>  }
>  
>  /* bio.c */
> -extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
> +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);
> -- 
> 2.17.0.484.g0c8726318c-goog

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[PATCH v2 2/2] f2fs: refactor read path to allow multiple postprocessing steps

[Eric Biggers via Linux-f2fs-devel]

Currently f2fs's ->readpage() and ->readpages() assume that either the
data undergoes no postprocessing, or decryption only.  But with
fs-verity, there will be an additional authenticity verification step,
and it may be needed either by itself, or combined with decryption.

To support this, store a 'struct bio_post_read_ctx' in ->bi_private
which contains a work struct, a bitmask of postprocessing steps that are
enabled, and an indicator of the current step.  The bio completion
routine, if there was no I/O error, enqueues the first postprocessing
step.  When that completes, it continues to the next step.  Pages that
fail any postprocessing step have PageError set.  Once all steps have
completed, pages without PageError set are set Uptodate, and all pages
are unlocked.

Also replace f2fs_encrypted_file() with a new function
f2fs_post_read_required() in places like direct I/O and garbage
collection that really should be testing whether the file needs special
I/O processing, not whether it is encrypted specifically.

This may also be useful for other future f2fs features such as
compression.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/f2fs/data.c   | 166 +++++++++++++++++++++++++++++++++++------------
 fs/f2fs/f2fs.h   |  12 +++-
 fs/f2fs/file.c   |   4 +-
 fs/f2fs/gc.c     |   6 +-
 fs/f2fs/inline.c |   2 +-
 fs/f2fs/super.c  |   6 ++
 6 files changed, 147 insertions(+), 49 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 39225519de1c..ad503603ceec 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -30,6 +30,11 @@
 #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;
@@ -50,11 +55,77 @@ static bool __is_cp_guaranteed(struct page *page)
 	return false;
 }
 
-static void f2fs_read_end_io(struct bio *bio)
+/* postprocessing steps for read bios */
+enum bio_post_read_step {
+	STEP_INITIAL = 0,
+	STEP_DECRYPT,
+};
+
+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 bio_vec *bvec;
+	struct page *page;
+	struct bio_vec *bv;
 	int i;
 
+	bio_for_each_segment_all(bv, bio, i) {
+		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 bio_post_read_processing(struct bio_post_read_ctx *ctx)
+{
+	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 */
+	default:
+		__read_end_io(ctx->bio);
+	}
+}
+
+static bool f2fs_bio_post_read_required(struct bio *bio)
+{
+	return bio->bi_private && !bio->bi_status;
+}
+
+static void f2fs_read_end_io(struct bio *bio)
+{
 #ifdef CONFIG_F2FS_FAULT_INJECTION
 	if (time_to_inject(F2FS_P_SB(bio_first_page_all(bio)), FAULT_IO)) {
 		f2fs_show_injection_info(FAULT_IO);
@@ -62,28 +133,15 @@ static void f2fs_read_end_io(struct bio *bio)
 	}
 #endif
 
-	if (f2fs_bio_encrypted(bio)) {
-		if (bio->bi_status) {
-			fscrypt_release_ctx(bio->bi_private);
-		} else {
-			fscrypt_enqueue_decrypt_bio(bio->bi_private, bio);
-			return;
-		}
-	}
-
-	bio_for_each_segment_all(bvec, bio, i) {
-		struct page *page = bvec->bv_page;
+	if (f2fs_bio_post_read_required(bio)) {
+		struct bio_post_read_ctx *ctx = bio->bi_private;
 
-		if (!bio->bi_status) {
-			if (!PageUptodate(page))
-				SetPageUptodate(page);
-		} else {
-			ClearPageUptodate(page);
-			SetPageError(page);
-		}
-		unlock_page(page);
+		ctx->cur_step = STEP_INITIAL;
+		bio_post_read_processing(ctx);
+		return;
 	}
-	bio_put(bio);
+
+	__read_end_io(bio);
 }
 
 static void f2fs_write_end_io(struct bio *bio)
@@ -481,29 +539,33 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 							 unsigned nr_pages)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct fscrypt_ctx *ctx = NULL;
 	struct bio *bio;
-
-	if (f2fs_encrypted_file(inode)) {
-		ctx = fscrypt_get_ctx(inode, GFP_NOFS);
-		if (IS_ERR(ctx))
-			return ERR_CAST(ctx);
-
-		/* wait the page to be moved by cleaning */
-		f2fs_wait_on_block_writeback(sbi, blkaddr);
-	}
+	struct bio_post_read_ctx *ctx;
+	unsigned int post_read_steps = 0;
 
 	bio = f2fs_bio_alloc(sbi, min_t(int, nr_pages, BIO_MAX_PAGES), false);
-	if (!bio) {
-		if (ctx)
-			fscrypt_release_ctx(ctx);
+	if (!bio)
 		return ERR_PTR(-ENOMEM);
-	}
 	f2fs_target_device(sbi, blkaddr, bio);
 	bio->bi_end_io = f2fs_read_end_io;
-	bio->bi_private = ctx;
 	bio_set_op_attrs(bio, REQ_OP_READ, 0);
 
+	if (f2fs_encrypted_file(inode))
+		post_read_steps |= 1 << STEP_DECRYPT;
+	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;
+
+		/* wait the page to be moved by cleaning */
+		f2fs_wait_on_block_writeback(sbi, blkaddr);
+	}
+
 	return bio;
 }
 
@@ -1525,7 +1587,7 @@ static int encrypt_one_page(struct f2fs_io_info *fio)
 	if (!f2fs_encrypted_file(inode))
 		return 0;
 
-	/* wait for GCed encrypted page writeback */
+	/* wait for GCed page writeback via META_MAPPING */
 	f2fs_wait_on_block_writeback(fio->sbi, fio->old_blkaddr);
 
 retry_encrypt:
@@ -2222,8 +2284,8 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 
 	f2fs_wait_on_page_writeback(page, DATA, false);
 
-	/* wait for GCed encrypted page writeback */
-	if (f2fs_encrypted_file(inode))
+	/* wait for GCed page writeback via META_MAPPING */
+	if (f2fs_post_read_required(inode))
 		f2fs_wait_on_block_writeback(sbi, blkaddr);
 
 	if (len == PAGE_SIZE || PageUptodate(page))
@@ -2555,3 +2617,27 @@ const struct address_space_operations f2fs_dblock_aops = {
 	.migratepage    = f2fs_migrate_page,
 #endif
 };
+
+int __init f2fs_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;
+}
+
+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/f2fs.h b/fs/f2fs/f2fs.h
index 1df7f10476d6..ea92c18db624 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2858,6 +2858,8 @@ void destroy_checkpoint_caches(void);
 /*
  * data.c
  */
+int f2fs_init_post_read_processing(void);
+void f2fs_destroy_post_read_processing(void);
 void f2fs_submit_merged_write(struct f2fs_sb_info *sbi, enum page_type type);
 void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi,
 				struct inode *inode, nid_t ino, pgoff_t idx,
@@ -3218,9 +3220,13 @@ static inline void f2fs_set_encrypted_inode(struct inode *inode)
 #endif
 }
 
-static inline bool f2fs_bio_encrypted(struct bio *bio)
+/*
+ * Returns true if the reads of the inode's data need to undergo some
+ * postprocessing step, like decryption or authenticity verification.
+ */
+static inline bool f2fs_post_read_required(struct inode *inode)
 {
-	return bio->bi_private != NULL;
+	return f2fs_encrypted_file(inode);
 }
 
 #define F2FS_FEATURE_FUNCS(name, flagname) \
@@ -3288,7 +3294,7 @@ static inline bool f2fs_may_encrypt(struct inode *inode)
 
 static inline bool f2fs_force_buffered_io(struct inode *inode, int rw)
 {
-	return (f2fs_encrypted_file(inode) ||
+	return (f2fs_post_read_required(inode) ||
 			(rw == WRITE && test_opt(F2FS_I_SB(inode), LFS)) ||
 			F2FS_I_SB(inode)->s_ndevs);
 }
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 6b94f19b3fa8..cc08956334a0 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -110,8 +110,8 @@ static int f2fs_vm_page_mkwrite(struct vm_fault *vmf)
 	/* fill the page */
 	f2fs_wait_on_page_writeback(page, DATA, false);
 
-	/* wait for GCed encrypted page writeback */
-	if (f2fs_encrypted_file(inode))
+	/* wait for GCed page writeback via META_MAPPING */
+	if (f2fs_post_read_required(inode))
 		f2fs_wait_on_block_writeback(sbi, dn.data_blkaddr);
 
 out_sem:
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 9327411fd93b..70418b34c5f6 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -850,8 +850,8 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 			if (IS_ERR(inode) || is_bad_inode(inode))
 				continue;
 
-			/* if encrypted inode, let's go phase 3 */
-			if (f2fs_encrypted_file(inode)) {
+			/* if inode uses special I/O path, let's go phase 3 */
+			if (f2fs_post_read_required(inode)) {
 				add_gc_inode(gc_list, inode);
 				continue;
 			}
@@ -899,7 +899,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 
 			start_bidx = start_bidx_of_node(nofs, inode)
 								+ ofs_in_node;
-			if (f2fs_encrypted_file(inode))
+			if (f2fs_post_read_required(inode))
 				move_data_block(inode, start_bidx, segno, off);
 			else
 				move_data_page(inode, start_bidx, gc_type,
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 265da200daa8..767e41d944c6 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -25,7 +25,7 @@ bool f2fs_may_inline_data(struct inode *inode)
 	if (i_size_read(inode) > MAX_INLINE_DATA(inode))
 		return false;
 
-	if (f2fs_encrypted_file(inode))
+	if (f2fs_post_read_required(inode))
 		return false;
 
 	return true;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 42d564c5ccd0..f31643718c76 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3092,8 +3092,13 @@ static int __init init_f2fs_fs(void)
 	err = f2fs_create_root_stats();
 	if (err)
 		goto free_filesystem;
+	err = f2fs_init_post_read_processing();
+	if (err)
+		goto free_root_stats;
 	return 0;
 
+free_root_stats:
+	f2fs_destroy_root_stats();
 free_filesystem:
 	unregister_filesystem(&f2fs_fs_type);
 free_shrinker:
@@ -3116,6 +3121,7 @@ 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);
-- 
2.17.0.484.g0c8726318c-goog


------------------------------------------------------------------------------
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Re: [PATCH v2 2/2] f2fs: refactor read path to allow multiple postprocessing steps

[Jaegeuk Kim]

Queued in f2fs/dev.
Thanks,

On 04/18, Eric Biggers wrote:
> Currently f2fs's ->readpage() and ->readpages() assume that either the
> data undergoes no postprocessing, or decryption only.  But with
> fs-verity, there will be an additional authenticity verification step,
> and it may be needed either by itself, or combined with decryption.
> 
> To support this, store a 'struct bio_post_read_ctx' in ->bi_private
> which contains a work struct, a bitmask of postprocessing steps that are
> enabled, and an indicator of the current step.  The bio completion
> routine, if there was no I/O error, enqueues the first postprocessing
> step.  When that completes, it continues to the next step.  Pages that
> fail any postprocessing step have PageError set.  Once all steps have
> completed, pages without PageError set are set Uptodate, and all pages
> are unlocked.
> 
> Also replace f2fs_encrypted_file() with a new function
> f2fs_post_read_required() in places like direct I/O and garbage
> collection that really should be testing whether the file needs special
> I/O processing, not whether it is encrypted specifically.
> 
> This may also be useful for other future f2fs features such as
> compression.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
>  fs/f2fs/data.c   | 166 +++++++++++++++++++++++++++++++++++------------
>  fs/f2fs/f2fs.h   |  12 +++-
>  fs/f2fs/file.c   |   4 +-
>  fs/f2fs/gc.c     |   6 +-
>  fs/f2fs/inline.c |   2 +-
>  fs/f2fs/super.c  |   6 ++
>  6 files changed, 147 insertions(+), 49 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 39225519de1c..ad503603ceec 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -30,6 +30,11 @@
>  #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;
> @@ -50,11 +55,77 @@ static bool __is_cp_guaranteed(struct page *page)
>  	return false;
>  }
>  
> -static void f2fs_read_end_io(struct bio *bio)
> +/* postprocessing steps for read bios */
> +enum bio_post_read_step {
> +	STEP_INITIAL = 0,
> +	STEP_DECRYPT,
> +};
> +
> +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 bio_vec *bvec;
> +	struct page *page;
> +	struct bio_vec *bv;
>  	int i;
>  
> +	bio_for_each_segment_all(bv, bio, i) {
> +		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 bio_post_read_processing(struct bio_post_read_ctx *ctx)
> +{
> +	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 */
> +	default:
> +		__read_end_io(ctx->bio);
> +	}
> +}
> +
> +static bool f2fs_bio_post_read_required(struct bio *bio)
> +{
> +	return bio->bi_private && !bio->bi_status;
> +}
> +
> +static void f2fs_read_end_io(struct bio *bio)
> +{
>  #ifdef CONFIG_F2FS_FAULT_INJECTION
>  	if (time_to_inject(F2FS_P_SB(bio_first_page_all(bio)), FAULT_IO)) {
>  		f2fs_show_injection_info(FAULT_IO);
> @@ -62,28 +133,15 @@ static void f2fs_read_end_io(struct bio *bio)
>  	}
>  #endif
>  
> -	if (f2fs_bio_encrypted(bio)) {
> -		if (bio->bi_status) {
> -			fscrypt_release_ctx(bio->bi_private);
> -		} else {
> -			fscrypt_enqueue_decrypt_bio(bio->bi_private, bio);
> -			return;
> -		}
> -	}
> -
> -	bio_for_each_segment_all(bvec, bio, i) {
> -		struct page *page = bvec->bv_page;
> +	if (f2fs_bio_post_read_required(bio)) {
> +		struct bio_post_read_ctx *ctx = bio->bi_private;
>  
> -		if (!bio->bi_status) {
> -			if (!PageUptodate(page))
> -				SetPageUptodate(page);
> -		} else {
> -			ClearPageUptodate(page);
> -			SetPageError(page);
> -		}
> -		unlock_page(page);
> +		ctx->cur_step = STEP_INITIAL;
> +		bio_post_read_processing(ctx);
> +		return;
>  	}
> -	bio_put(bio);
> +
> +	__read_end_io(bio);
>  }
>  
>  static void f2fs_write_end_io(struct bio *bio)
> @@ -481,29 +539,33 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
>  							 unsigned nr_pages)
>  {
>  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> -	struct fscrypt_ctx *ctx = NULL;
>  	struct bio *bio;
> -
> -	if (f2fs_encrypted_file(inode)) {
> -		ctx = fscrypt_get_ctx(inode, GFP_NOFS);
> -		if (IS_ERR(ctx))
> -			return ERR_CAST(ctx);
> -
> -		/* wait the page to be moved by cleaning */
> -		f2fs_wait_on_block_writeback(sbi, blkaddr);
> -	}
> +	struct bio_post_read_ctx *ctx;
> +	unsigned int post_read_steps = 0;
>  
>  	bio = f2fs_bio_alloc(sbi, min_t(int, nr_pages, BIO_MAX_PAGES), false);
> -	if (!bio) {
> -		if (ctx)
> -			fscrypt_release_ctx(ctx);
> +	if (!bio)
>  		return ERR_PTR(-ENOMEM);
> -	}
>  	f2fs_target_device(sbi, blkaddr, bio);
>  	bio->bi_end_io = f2fs_read_end_io;
> -	bio->bi_private = ctx;
>  	bio_set_op_attrs(bio, REQ_OP_READ, 0);
>  
> +	if (f2fs_encrypted_file(inode))
> +		post_read_steps |= 1 << STEP_DECRYPT;
> +	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;
> +
> +		/* wait the page to be moved by cleaning */
> +		f2fs_wait_on_block_writeback(sbi, blkaddr);
> +	}
> +
>  	return bio;
>  }
>  
> @@ -1525,7 +1587,7 @@ static int encrypt_one_page(struct f2fs_io_info *fio)
>  	if (!f2fs_encrypted_file(inode))
>  		return 0;
>  
> -	/* wait for GCed encrypted page writeback */
> +	/* wait for GCed page writeback via META_MAPPING */
>  	f2fs_wait_on_block_writeback(fio->sbi, fio->old_blkaddr);
>  
>  retry_encrypt:
> @@ -2222,8 +2284,8 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
>  
>  	f2fs_wait_on_page_writeback(page, DATA, false);
>  
> -	/* wait for GCed encrypted page writeback */
> -	if (f2fs_encrypted_file(inode))
> +	/* wait for GCed page writeback via META_MAPPING */
> +	if (f2fs_post_read_required(inode))
>  		f2fs_wait_on_block_writeback(sbi, blkaddr);
>  
>  	if (len == PAGE_SIZE || PageUptodate(page))
> @@ -2555,3 +2617,27 @@ const struct address_space_operations f2fs_dblock_aops = {
>  	.migratepage    = f2fs_migrate_page,
>  #endif
>  };
> +
> +int __init f2fs_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;
> +}
> +
> +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/f2fs.h b/fs/f2fs/f2fs.h
> index 1df7f10476d6..ea92c18db624 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -2858,6 +2858,8 @@ void destroy_checkpoint_caches(void);
>  /*
>   * data.c
>   */
> +int f2fs_init_post_read_processing(void);
> +void f2fs_destroy_post_read_processing(void);
>  void f2fs_submit_merged_write(struct f2fs_sb_info *sbi, enum page_type type);
>  void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi,
>  				struct inode *inode, nid_t ino, pgoff_t idx,
> @@ -3218,9 +3220,13 @@ static inline void f2fs_set_encrypted_inode(struct inode *inode)
>  #endif
>  }
>  
> -static inline bool f2fs_bio_encrypted(struct bio *bio)
> +/*
> + * Returns true if the reads of the inode's data need to undergo some
> + * postprocessing step, like decryption or authenticity verification.
> + */
> +static inline bool f2fs_post_read_required(struct inode *inode)
>  {
> -	return bio->bi_private != NULL;
> +	return f2fs_encrypted_file(inode);
>  }
>  
>  #define F2FS_FEATURE_FUNCS(name, flagname) \
> @@ -3288,7 +3294,7 @@ static inline bool f2fs_may_encrypt(struct inode *inode)
>  
>  static inline bool f2fs_force_buffered_io(struct inode *inode, int rw)
>  {
> -	return (f2fs_encrypted_file(inode) ||
> +	return (f2fs_post_read_required(inode) ||
>  			(rw == WRITE && test_opt(F2FS_I_SB(inode), LFS)) ||
>  			F2FS_I_SB(inode)->s_ndevs);
>  }
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 6b94f19b3fa8..cc08956334a0 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -110,8 +110,8 @@ static int f2fs_vm_page_mkwrite(struct vm_fault *vmf)
>  	/* fill the page */
>  	f2fs_wait_on_page_writeback(page, DATA, false);
>  
> -	/* wait for GCed encrypted page writeback */
> -	if (f2fs_encrypted_file(inode))
> +	/* wait for GCed page writeback via META_MAPPING */
> +	if (f2fs_post_read_required(inode))
>  		f2fs_wait_on_block_writeback(sbi, dn.data_blkaddr);
>  
>  out_sem:
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 9327411fd93b..70418b34c5f6 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -850,8 +850,8 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>  			if (IS_ERR(inode) || is_bad_inode(inode))
>  				continue;
>  
> -			/* if encrypted inode, let's go phase 3 */
> -			if (f2fs_encrypted_file(inode)) {
> +			/* if inode uses special I/O path, let's go phase 3 */
> +			if (f2fs_post_read_required(inode)) {
>  				add_gc_inode(gc_list, inode);
>  				continue;
>  			}
> @@ -899,7 +899,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>  
>  			start_bidx = start_bidx_of_node(nofs, inode)
>  								+ ofs_in_node;
> -			if (f2fs_encrypted_file(inode))
> +			if (f2fs_post_read_required(inode))
>  				move_data_block(inode, start_bidx, segno, off);
>  			else
>  				move_data_page(inode, start_bidx, gc_type,
> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
> index 265da200daa8..767e41d944c6 100644
> --- a/fs/f2fs/inline.c
> +++ b/fs/f2fs/inline.c
> @@ -25,7 +25,7 @@ bool f2fs_may_inline_data(struct inode *inode)
>  	if (i_size_read(inode) > MAX_INLINE_DATA(inode))
>  		return false;
>  
> -	if (f2fs_encrypted_file(inode))
> +	if (f2fs_post_read_required(inode))
>  		return false;
>  
>  	return true;
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 42d564c5ccd0..f31643718c76 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -3092,8 +3092,13 @@ static int __init init_f2fs_fs(void)
>  	err = f2fs_create_root_stats();
>  	if (err)
>  		goto free_filesystem;
> +	err = f2fs_init_post_read_processing();
> +	if (err)
> +		goto free_root_stats;
>  	return 0;
>  
> +free_root_stats:
> +	f2fs_destroy_root_stats();
>  free_filesystem:
>  	unregister_filesystem(&f2fs_fs_type);
>  free_shrinker:
> @@ -3116,6 +3121,7 @@ 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);
> -- 
> 2.17.0.484.g0c8726318c-goog

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Re: [PATCH v2 2/2] f2fs: refactor read path to allow multiple postprocessing steps

[Chao Yu]

On 2018/4/19 2:09, Eric Biggers via Linux-f2fs-devel wrote:
> Currently f2fs's ->readpage() and ->readpages() assume that either the
> data undergoes no postprocessing, or decryption only.  But with
> fs-verity, there will be an additional authenticity verification step,
> and it may be needed either by itself, or combined with decryption.
> 
> To support this, store a 'struct bio_post_read_ctx' in ->bi_private
> which contains a work struct, a bitmask of postprocessing steps that are
> enabled, and an indicator of the current step.  The bio completion
> routine, if there was no I/O error, enqueues the first postprocessing
> step.  When that completes, it continues to the next step.  Pages that
> fail any postprocessing step have PageError set.  Once all steps have
> completed, pages without PageError set are set Uptodate, and all pages
> are unlocked.
> 
> Also replace f2fs_encrypted_file() with a new function
> f2fs_post_read_required() in places like direct I/O and garbage
> collection that really should be testing whether the file needs special
> I/O processing, not whether it is encrypted specifically.
> 
> This may also be useful for other future f2fs features such as
> compression.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,


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