On Wednesday, February 20, 2019 4:52:44 AM IST Eric Biggers wrote:
> Hi Chandan,
>
> On Mon, Feb 18, 2019 at 03:34:27PM +0530, Chandan Rajendra wrote:
> > 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@xxxxxxxxxxxxx>
> > ---
> > fs/Makefile | 3 +-
> > fs/crypto/bio.c | 21 ++--
> > fs/crypto/crypto.c | 1 +
> > fs/crypto/fscrypt_private.h | 3 +
> > fs/ext4/ext4.h | 2 -
> > fs/ext4/readpage.c | 153 +-----------------------------
> > fs/ext4/super.c | 9 +-
> > fs/post_read_process.c | 127 +++++++++++++++++++++++++
> > fs/verity/verify.c | 12 +++
> > include/linux/fscrypt.h | 11 ---
> > include/linux/post_read_process.h | 21 ++++
> > 11 files changed, 176 insertions(+), 187 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 10b37f651ffd..5f6c0cba102b 100644
> > --- a/fs/Makefile
> > +++ b/fs/Makefile
> > @@ -12,7 +12,8 @@ obj-y := open.o read_write.o file_table.o super.o \
> > attr.o bad_inode.o file.o filesystems.o namespace.o \
> > seq_file.o xattr.o libfs.o fs-writeback.o \
> > pnode.o splice.o sync.o utimes.o d_path.o \
> > - stack.o fs_struct.o statfs.o fs_pin.o nsfs.o
> > + stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
> > + post_read_process.o
> >
>
> To avoid bloating every Linux kernel in existence, post_read_process.c should
> only be compiled if CONFIG_FS_ENCRYPTION || CONFIG_FS_VERITY.
>
Will do.
> > ifeq ($(CONFIG_BLOCK),y)
> > obj-y += buffer.o block_dev.o direct-io.o mpage.o
> > diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
> > index 0959044c5cee..a659a76c05e4 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)
> > @@ -53,24 +55,15 @@ 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)
> > {
> > diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
> > index 4dc788e3bc96..36d599784e5a 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);
> > 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 0ffa84772667..c0245820bafe 100644
> > --- a/fs/ext4/ext4.h
> > +++ b/fs/ext4/ext4.h
> > @@ -3088,8 +3088,6 @@ 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 93fbc15177a3..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
> > @@ -61,124 +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;
> > -
> > - 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 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.
> > *
> > @@ -196,11 +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)
> > @@ -416,29 +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 95a5d9fbbb9f..9314dddfbf34 100644
> > --- a/fs/ext4/super.c
> > +++ b/fs/ext4/super.c
> > @@ -6102,10 +6102,6 @@ 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;
> >
> > @@ -6147,10 +6143,8 @@ 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;
> > @@ -6167,7 +6161,6 @@ 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/post_read_process.c b/fs/post_read_process.c
> > new file mode 100644
> > index 000000000000..9720eeff0160
> > --- /dev/null
> > +++ b/fs/post_read_process.c
> > @@ -0,0 +1,127 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +#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>
>
> To help people who come across this code, please add a comment at the top of
> this file that briefly describes what it is.
>
Sure, I will add a header describing the the code's utility.
> > +
> > +#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;
> > +
> > + 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)
> > + put_bio_post_read_ctx(bio->bi_private);
> > + bio_put(bio);
> > +}
> > +
> > +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);
> > + }
> > +}
> > +
> > +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;
> > +}
> > +
> > +void put_bio_post_read_ctx(struct bio_post_read_ctx *ctx)
> > +{
> > + mempool_free(ctx, bio_post_read_ctx_pool);
> > +}
> > +
> > +bool bio_post_read_required(struct bio *bio)
> > +{
> > + return bio->bi_private && !bio->bi_status;
> > +}
> > +
> > +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 fbfb68eff358..4f7cd2269e83 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;
> >
> > @@ -283,6 +284,16 @@ 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
> > *
> > @@ -290,6 +301,7 @@ 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 6ba193c23f37..13f70e22aff2 100644
> > --- a/include/linux/fscrypt.h
> > +++ b/include/linux/fscrypt.h
> > @@ -68,10 +68,6 @@ struct fscrypt_ctx {
> > struct page *bounce_page; /* Ciphertext page */
> > struct page *control_page; /* Original page */
> > } w;
> > - struct {
> > - struct bio *bio;
> > - struct work_struct work;
> > - } r;
>
> Now that 'struct fscrypt_ctx' is only used for writes, the 'w' part should be
> changed to an anonymous struct.
Ok. I will change that.
>
> > struct list_head free_list; /* Free list */
> > };
> > u8 flags; /* Flags */
> > @@ -206,8 +202,6 @@ 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);
> > @@ -376,11 +370,6 @@ 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)
> > {
> > return;
> > 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 */
>
> - Eric
>
>
--
chandan
