From: Chandan Rajendra Subject: [RFC PATCH V2 10/11] Enable writing encrypted files in blocksize less than pagesize setup Date: Mon, 12 Feb 2018 15:13:46 +0530 Message-ID: <20180212094347.22071-11-chandan@linux.vnet.ibm.com> References: <20180212094347.22071-1-chandan@linux.vnet.ibm.com> Cc: Chandan Rajendra , linux-fsdevel@vger.kernel.org, ebiggers3@gmail.com, linux-fscrypt@vger.kernel.org, tytso@mit.edu To: linux-ext4@vger.kernel.org Return-path: In-Reply-To: <20180212094347.22071-1-chandan@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org This commit splits the functionality of fscrypt_encrypt_block(). The allocation of fscrypt context and cipher text page is moved to a new function fscrypt_prep_ciphertext_page(). ext4_bio_write_page() is modified to appropriately make use of the above two functions. Signed-off-by: Chandan Rajendra --- fs/crypto/crypto.c | 71 +++++++++++++++++++++-------------------- fs/ext4/page-io.c | 34 +++++++++++++------- include/linux/fscrypt_notsupp.h | 16 +++++++--- include/linux/fscrypt_supp.h | 9 ++++-- 4 files changed, 75 insertions(+), 55 deletions(-) diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 24e3796..8fb27ee 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -195,6 +195,35 @@ struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx, return ctx->w.bounce_page; } +struct page *fscrypt_prep_ciphertext_page(struct inode *inode, + struct page *page, + gfp_t gfp_flags) +{ + struct page *ciphertext_page; + struct fscrypt_ctx *ctx; + + BUG_ON(!PageLocked(page)); + + ctx = fscrypt_get_ctx(inode, gfp_flags); + if (IS_ERR(ctx)) + return ERR_CAST(ctx); + + ctx->w.control_page = page; + + ciphertext_page = fscrypt_alloc_bounce_page(ctx, gfp_flags); + if (IS_ERR(ciphertext_page)) { + fscrypt_release_ctx(ctx); + return ERR_CAST(ciphertext_page); + } + + SetPagePrivate(ciphertext_page); + set_page_private(ciphertext_page, (unsigned long)ctx); + lock_page(ciphertext_page); + + return ciphertext_page; +} +EXPORT_SYMBOL(fscrypt_prep_ciphertext_page); + /** * fscypt_encrypt_page() - Encrypts a page * @inode: The inode for which the encryption should take place @@ -226,15 +255,11 @@ struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx, * Return: A page with the encrypted content on success. Else, an * error value or NULL. */ -struct page *fscrypt_encrypt_block(const struct inode *inode, - struct page *page, - unsigned int len, - unsigned int offs, - u64 lblk_num, gfp_t gfp_flags) - +int fscrypt_encrypt_block(const struct inode *inode, + struct page *page, struct page *ciphertext_page, + unsigned int len, unsigned int offs, + u64 lblk_num, gfp_t gfp_flags) { - struct fscrypt_ctx *ctx; - struct page *ciphertext_page = page; int err; BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0); @@ -242,41 +267,17 @@ struct page *fscrypt_encrypt_block(const struct inode *inode, if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) { /* with inplace-encryption we just encrypt the page */ err = fscrypt_do_block_crypto(inode, FS_ENCRYPT, lblk_num, page, - ciphertext_page, len, offs, - gfp_flags); - if (err) - return ERR_PTR(err); - - return ciphertext_page; + page, len, offs, gfp_flags); + return err; } BUG_ON(!PageLocked(page)); - ctx = fscrypt_get_ctx(inode, gfp_flags); - if (IS_ERR(ctx)) - return (struct page *)ctx; - - /* The encryption operation will require a bounce page. */ - ciphertext_page = fscrypt_alloc_bounce_page(ctx, gfp_flags); - if (IS_ERR(ciphertext_page)) - goto errout; - - ctx->w.control_page = page; err = fscrypt_do_block_crypto(inode, FS_ENCRYPT, lblk_num, page, ciphertext_page, len, offs, gfp_flags); - if (err) { - ciphertext_page = ERR_PTR(err); - goto errout; - } - SetPagePrivate(ciphertext_page); - set_page_private(ciphertext_page, (unsigned long)ctx); - lock_page(ciphertext_page); - return ciphertext_page; + return err; -errout: - fscrypt_release_ctx(ctx); - return ciphertext_page; } EXPORT_SYMBOL(fscrypt_encrypt_block); diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 0a4a1e7..1e869d5 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -419,9 +419,12 @@ int ext4_bio_write_page(struct ext4_io_submit *io, struct inode *inode = page->mapping->host; unsigned block_start; struct buffer_head *bh, *head; + u64 blk_nr; + gfp_t gfp_flags = GFP_NOFS; int ret = 0; int nr_submitted = 0; int nr_to_submit = 0; + int blocksize = (1 << inode->i_blkbits); BUG_ON(!PageLocked(page)); BUG_ON(PageWriteback(page)); @@ -475,15 +478,11 @@ int ext4_bio_write_page(struct ext4_io_submit *io, nr_to_submit++; } while ((bh = bh->b_this_page) != head); - bh = head = page_buffers(page); - - if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode) && - nr_to_submit) { - gfp_t gfp_flags = GFP_NOFS; - - retry_encrypt: - data_page = fscrypt_encrypt_block(inode, page, PAGE_SIZE, 0, - page->index, gfp_flags); + if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode) + && nr_to_submit) { + retry_prep_ciphertext_page: + data_page = fscrypt_prep_ciphertext_page(inode, page, + gfp_flags); if (IS_ERR(data_page)) { ret = PTR_ERR(data_page); if (ret == -ENOMEM && wbc->sync_mode == WB_SYNC_ALL) { @@ -492,17 +491,28 @@ int ext4_bio_write_page(struct ext4_io_submit *io, congestion_wait(BLK_RW_ASYNC, HZ/50); } gfp_flags |= __GFP_NOFAIL; - goto retry_encrypt; + goto retry_prep_ciphertext_page; } data_page = NULL; goto out; } } + blk_nr = page->index << (PAGE_SHIFT - inode->i_blkbits); + /* Now submit buffers to write */ + bh = head = page_buffers(page); do { if (!buffer_async_write(bh)) continue; + + if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode)) { + ret = fscrypt_encrypt_block(inode, page, data_page, blocksize, + bh_offset(bh), blk_nr, gfp_flags); + if (ret) + break; + } + ret = io_submit_add_bh(io, inode, data_page ? data_page : page, bh); if (ret) { @@ -515,12 +525,12 @@ int ext4_bio_write_page(struct ext4_io_submit *io, } nr_submitted++; clear_buffer_dirty(bh); - } while ((bh = bh->b_this_page) != head); + } while (++blk_nr, (bh = bh->b_this_page) != head); /* Error stopped previous loop? Clean up buffers... */ if (ret) { out: - if (data_page) + if (data_page && bh == head) fscrypt_restore_control_page(data_page); printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret); redirty_page_for_writepage(wbc, page); diff --git a/include/linux/fscrypt_notsupp.h b/include/linux/fscrypt_notsupp.h index aeb6b6d..3b0a53b 100644 --- a/include/linux/fscrypt_notsupp.h +++ b/include/linux/fscrypt_notsupp.h @@ -26,15 +26,21 @@ 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_prep_ciphertext_page(struct inode *inode, + struct page *page, + gfp_t gfp_flags) { return ERR_PTR(-EOPNOTSUPP); } +static inline int fscrypt_encrypt_block(const struct inode *inode, + struct page *page, struct page *ciphertext_page, + unsigned int len, unsigned int offs, + u64 lblk_num, gfp_t gfp_flags) +{ + return -EOPNOTSUPP; +} + static inline int fscrypt_decrypt_block(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, diff --git a/include/linux/fscrypt_supp.h b/include/linux/fscrypt_supp.h index b4c5231..68a5e91 100644 --- a/include/linux/fscrypt_supp.h +++ b/include/linux/fscrypt_supp.h @@ -15,9 +15,12 @@ extern struct kmem_cache *fscrypt_info_cachep; 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_block(const struct inode *, struct page *, - unsigned int, unsigned int, - u64, gfp_t); +extern struct page *fscrypt_prep_ciphertext_page(struct inode *, struct page *, + gfp_t); +extern int fscrypt_encrypt_block(const struct inode *inode, + struct page *page, struct page *ciphertext_page, + unsigned int len, unsigned int offs, + u64 lblk_num, gfp_t gfp_flags); extern int fscrypt_decrypt_block(const struct inode *, struct page *, unsigned int, unsigned int, u64); extern void fscrypt_restore_control_page(struct page *); -- 2.9.5