From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Biggers Subject: Re: [PATCH V2 12/13] fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page Date: Tue, 30 Apr 2019 09:51:15 -0700 Message-ID: <20190430165114.GA48973@gmail.com> References: <20190428043121.30925-1-chandan@linux.ibm.com> <20190428043121.30925-13-chandan@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1hLVyc-0002yd-4k for linux-f2fs-devel@lists.sourceforge.net; Tue, 30 Apr 2019 16:51:30 +0000 Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-3.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) id 1hLVyV-001GYi-9M for linux-f2fs-devel@lists.sourceforge.net; Tue, 30 Apr 2019 16:51:30 +0000 Content-Disposition: inline In-Reply-To: <20190428043121.30925-13-chandan@linux.ibm.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Chandan Rajendra Cc: tytso@mit.edu, linux-f2fs-devel@lists.sourceforge.net, hch@infradead.org, linux-fscrypt@vger.kernel.org, adilger.kernel@dilger.ca, linux-fsdevel@vger.kernel.org, jaegeuk@kernel.org, linux-ext4@vger.kernel.org On Sun, Apr 28, 2019 at 10:01:20AM +0530, Chandan Rajendra wrote: > For subpage-sized blocks, this commit adds code to encrypt all zeroed > out blocks mapped by a page. > > Signed-off-by: Chandan Rajendra > --- > 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 856f4694902d..46dd2ec50c7d 100644 > --- a/fs/crypto/bio.c > +++ b/fs/crypto/bio.c > @@ -108,29 +108,23 @@ 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; page_bytes should be 'unsigned int', since it's <= PAGE_SIZE. > 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; Should cast len to 'u64' here, in case it's greater than UINT_MAX / blocksize. > > - 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; > + } 'ciphertext_page' is leaked after each loop iteration. Did you mean to free it, or did you mean to reuse it for subsequent iterations? > > bio = bio_alloc(GFP_NOWAIT, 1); > if (!bio) { > @@ -141,9 +135,8 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, > bio->bi_iter.bi_sector = > pblk << (inode->i_sb->s_blocksize_bits - 9); This line uses ->s_blocksize_bits, but your new code uses ->i_blkbits. AFAIK they'll always be the same, but please pick one or the other to use. > 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); > @@ -156,12 +149,15 @@ 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 >