From d2d0727b1654e11563f181f4d3d48b9275514480 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 20 May 2019 09:29:39 -0700 Subject: fscrypt: simplify bounce page handling Currently, bounce page handling for writes to encrypted files is unnecessarily complicated. A fscrypt_ctx is allocated along with each bounce page, page_private(bounce_page) points to this fscrypt_ctx, and fscrypt_ctx::w::control_page points to the original pagecache page. However, because writes don't use the fscrypt_ctx for anything else, there's no reason why page_private(bounce_page) can't just point to the original pagecache page directly. Therefore, this patch makes this change. In the process, it also cleans up the API exposed to filesystems that allows testing whether a page is a bounce page, getting the pagecache page from a bounce page, and freeing a bounce page. Reviewed-by: Chandan Rajendra Signed-off-by: Eric Biggers --- include/linux/fscrypt.h | 38 ++++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-) (limited to 'include/linux') diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index f7680ef1abd2..d016fa384d60 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -112,12 +112,17 @@ extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *, extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int, unsigned int, u64); -static inline struct page *fscrypt_control_page(struct page *page) +static inline bool fscrypt_is_bounce_page(struct page *page) { - return ((struct fscrypt_ctx *)page_private(page))->w.control_page; + return page->mapping == NULL; } -extern void fscrypt_restore_control_page(struct page *); +static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) +{ + return (struct page *)page_private(bounce_page); +} + +extern void fscrypt_free_bounce_page(struct page *bounce_page); /* policy.c */ extern int fscrypt_ioctl_set_policy(struct file *, const void __user *); @@ -223,7 +228,6 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname, 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); @@ -300,15 +304,19 @@ static inline int fscrypt_decrypt_page(const struct inode *inode, return -EOPNOTSUPP; } -static inline struct page *fscrypt_control_page(struct page *page) +static inline bool fscrypt_is_bounce_page(struct page *page) +{ + return false; +} + +static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) { WARN_ON_ONCE(1); return ERR_PTR(-EINVAL); } -static inline void fscrypt_restore_control_page(struct page *page) +static inline void fscrypt_free_bounce_page(struct page *bounce_page) { - return; } /* policy.c */ @@ -410,11 +418,6 @@ static inline void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, { } -static inline void fscrypt_pullback_bio_page(struct page **page, bool restore) -{ - return; -} - static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, sector_t pblk, unsigned int len) { @@ -692,4 +695,15 @@ static inline int fscrypt_encrypt_symlink(struct inode *inode, return 0; } +/* If *pagep is a bounce page, free it and set *pagep to the pagecache page */ +static inline void fscrypt_finalize_bounce_page(struct page **pagep) +{ + struct page *page = *pagep; + + if (fscrypt_is_bounce_page(page)) { + *pagep = fscrypt_pagecache_page(page); + fscrypt_free_bounce_page(page); + } +} + #endif /* _LINUX_FSCRYPT_H */ -- cgit v1.2.3 From 2a415a0257314cb2e49fb9ac4c6770837112f261 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 20 May 2019 09:29:40 -0700 Subject: fscrypt: remove the "write" part of struct fscrypt_ctx Now that fscrypt_ctx is not used for writes, remove the 'w' fields. Reviewed-by: Chandan Rajendra Signed-off-by: Eric Biggers --- include/linux/fscrypt.h | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index d016fa384d60..1c7287f146a9 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -63,16 +63,13 @@ struct fscrypt_operations { unsigned int max_namelen; }; +/* Decryption work */ struct fscrypt_ctx { union { - 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 */ -- cgit v1.2.3 From 03569f2fb8e734f281379767de674e23c38b0b14 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 20 May 2019 09:29:43 -0700 Subject: fscrypt: introduce fscrypt_encrypt_block_inplace() fscrypt_encrypt_page() behaves very differently depending on whether the filesystem set FS_CFLG_OWN_PAGES in its fscrypt_operations. This makes the function difficult to understand and document. It also makes it so that all callers have to provide inode and lblk_num, when fscrypt could determine these itself for pagecache pages. Therefore, move the FS_CFLG_OWN_PAGES behavior into a new function fscrypt_encrypt_block_inplace(). This is in preparation for allowing encryption on ext4 filesystems with blocksize != PAGE_SIZE. Reviewed-by: Chandan Rajendra Signed-off-by: Eric Biggers --- include/linux/fscrypt.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux') diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 1c7287f146a9..a9b2d26e615d 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -106,6 +106,10 @@ extern void fscrypt_release_ctx(struct fscrypt_ctx *); extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *, unsigned int, unsigned int, u64, gfp_t); +extern int fscrypt_encrypt_block_inplace(const struct inode *inode, + struct page *page, unsigned int len, + unsigned int offs, u64 lblk_num, + gfp_t gfp_flags); extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int, unsigned int, u64); @@ -293,6 +297,15 @@ static inline struct page *fscrypt_encrypt_page(const struct inode *inode, return ERR_PTR(-EOPNOTSUPP); } +static inline int fscrypt_encrypt_block_inplace(const struct inode *inode, + struct page *page, + unsigned int len, + unsigned int offs, u64 lblk_num, + gfp_t gfp_flags) +{ + return -EOPNOTSUPP; +} + static inline int fscrypt_decrypt_page(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, -- cgit v1.2.3 From 53bc1d854c64c20d967dab15b111baca02a6d99e Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 20 May 2019 09:29:44 -0700 Subject: fscrypt: support encrypting multiple filesystem blocks per page Rename fscrypt_encrypt_page() to fscrypt_encrypt_pagecache_blocks() and redefine its behavior to encrypt all filesystem blocks from the given region of the given page, rather than assuming that the region consists of just one filesystem block. Also remove the 'inode' and 'lblk_num' parameters, since they can be retrieved from the page as it's already assumed to be a pagecache page. This is in preparation for allowing encryption on ext4 filesystems with blocksize != PAGE_SIZE. This is based on work by Chandan Rajendra. Reviewed-by: Chandan Rajendra Signed-off-by: Eric Biggers --- include/linux/fscrypt.h | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'include/linux') diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index a9b2d26e615d..c7e16bd16a6c 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -103,9 +103,11 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) extern void fscrypt_enqueue_decrypt_work(struct work_struct *); extern struct fscrypt_ctx *fscrypt_get_ctx(gfp_t); extern void fscrypt_release_ctx(struct fscrypt_ctx *); -extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *, - unsigned int, unsigned int, - u64, gfp_t); + +extern struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, + unsigned int len, + unsigned int offs, + gfp_t gfp_flags); extern int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num, @@ -288,11 +290,10 @@ static inline void fscrypt_release_ctx(struct fscrypt_ctx *ctx) return; } -static inline struct page *fscrypt_encrypt_page(const struct inode *inode, - struct page *page, - unsigned int len, - unsigned int offs, - u64 lblk_num, gfp_t gfp_flags) +static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, + unsigned int len, + unsigned int offs, + gfp_t gfp_flags) { return ERR_PTR(-EOPNOTSUPP); } -- cgit v1.2.3 From 41adbcb7267b0060682576d523956160b5c617bd Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 20 May 2019 09:29:46 -0700 Subject: fscrypt: introduce fscrypt_decrypt_block_inplace() Currently fscrypt_decrypt_page() does one of two logically distinct things depending on whether FS_CFLG_OWN_PAGES is set in the filesystem's fscrypt_operations: decrypt a pagecache page in-place, or decrypt a filesystem block in-place in any page. Currently these happen to share the same implementation, but this conflates the notion of blocks and pages. It also makes it so that all callers have to provide inode and lblk_num, when fscrypt could determine these itself for pagecache pages. Therefore, move the FS_CFLG_OWN_PAGES behavior into a new function fscrypt_decrypt_block_inplace(). This mirrors fscrypt_encrypt_block_inplace(). This is in preparation for allowing encryption on ext4 filesystems with blocksize != PAGE_SIZE. Reviewed-by: Chandan Rajendra Signed-off-by: Eric Biggers --- include/linux/fscrypt.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/linux') diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index c7e16bd16a6c..315affc99b05 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -114,6 +114,9 @@ extern int fscrypt_encrypt_block_inplace(const struct inode *inode, gfp_t gfp_flags); extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int, unsigned int, u64); +extern int fscrypt_decrypt_block_inplace(const struct inode *inode, + struct page *page, unsigned int len, + unsigned int offs, u64 lblk_num); static inline bool fscrypt_is_bounce_page(struct page *page) { @@ -315,6 +318,14 @@ static inline int fscrypt_decrypt_page(const struct inode *inode, return -EOPNOTSUPP; } +static inline int fscrypt_decrypt_block_inplace(const struct inode *inode, + struct page *page, + unsigned int len, + unsigned int offs, u64 lblk_num) +{ + return -EOPNOTSUPP; +} + static inline bool fscrypt_is_bounce_page(struct page *page) { return false; -- cgit v1.2.3 From aa8bc1ac6ef32a332671ca25e06cfd277a3839a5 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 20 May 2019 09:29:47 -0700 Subject: fscrypt: support decrypting multiple filesystem blocks per page Rename fscrypt_decrypt_page() to fscrypt_decrypt_pagecache_blocks() and redefine its behavior to decrypt all filesystem blocks in the given region of the given page, rather than assuming that the region consists of just one filesystem block. Also remove the 'inode' and 'lblk_num' parameters, since they can be retrieved from the page as it's already assumed to be a pagecache page. This is in preparation for allowing encryption on ext4 filesystems with blocksize != PAGE_SIZE. This is based on work by Chandan Rajendra. Reviewed-by: Chandan Rajendra Signed-off-by: Eric Biggers --- include/linux/fscrypt.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 315affc99b05..bd8f207a2fb6 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -112,8 +112,9 @@ extern int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num, gfp_t gfp_flags); -extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int, - unsigned int, u64); + +extern int fscrypt_decrypt_pagecache_blocks(struct page *page, unsigned int len, + unsigned int offs); extern int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num); @@ -310,10 +311,9 @@ static inline int fscrypt_encrypt_block_inplace(const struct inode *inode, return -EOPNOTSUPP; } -static inline int fscrypt_decrypt_page(const struct inode *inode, - struct page *page, - unsigned int len, unsigned int offs, - u64 lblk_num) +static inline int fscrypt_decrypt_pagecache_blocks(struct page *page, + unsigned int len, + unsigned int offs) { return -EOPNOTSUPP; } -- cgit v1.2.3