From: Chandan Rajendra <chandan@linux.ibm.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-fscrypt@vger.kernel.org, tytso@mit.edu,
adilger.kernel@dilger.ca, jaegeuk@kernel.org, yuchao0@huawei.com,
hch@infradead.org
Subject: Re: [PATCH V2 12/13] fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page
Date: Wed, 01 May 2019 19:52:02 +0530 [thread overview]
Message-ID: <5118219.DRdbvtsWY3@localhost.localdomain> (raw)
In-Reply-To: <20190430165114.GA48973@gmail.com>
On Tuesday, April 30, 2019 10:21:15 PM IST Eric Biggers wrote:
> 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 <chandan@linux.ibm.com>
> > ---
> > 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?
Thanks for pointing this out. I actually meant to free it. I will see if I can
reuse ciphertext_page in my next patchset rather than freeing and allocating
it each time the loop is executed.
>
> >
> > 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.
I will fix this.
>
> > 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);
>
>
--
chandan
next prev parent reply other threads:[~2019-05-01 14:21 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-28 4:31 [PATCH V2 00/13] Consolidate FS read I/O callbacks code Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 01/13] ext4: Clear BH_Uptodate flag on decryption error Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 02/13] Consolidate "read callbacks" into a new file Chandan Rajendra
2019-04-30 0:00 ` Eric Biggers
2019-05-01 12:30 ` Chandan Rajendra
2019-04-30 1:37 ` Chao Yu
2019-05-01 12:31 ` Chandan Rajendra
2019-04-30 18:05 ` Eric Biggers
2019-05-01 12:32 ` Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 03/13] fsverity: Add call back to decide if verity check has to be performed Chandan Rajendra
2019-04-30 21:10 ` Jeremy Sowden
2019-05-01 12:33 ` Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 04/13] fsverity: Add call back to determine readpage limit Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 05/13] fs/mpage.c: Integrate read callbacks Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 06/13] ext4: Wire up ext4_readpage[s] to use mpage_readpage[s] Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 07/13] Add decryption support for sub-pagesized blocks Chandan Rajendra
2019-04-30 0:38 ` Eric Biggers
2019-05-01 13:40 ` Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 08/13] ext4: Decrypt all boundary blocks when doing buffered write Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 09/13] ext4: Decrypt the block that needs to be partially zeroed Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 10/13] fscrypt_encrypt_page: Loop across all blocks mapped by a page range Chandan Rajendra
2019-04-30 17:11 ` Eric Biggers
2019-04-30 23:08 ` [f2fs-dev] " Eric Biggers
2019-05-01 14:49 ` Chandan Rajendra
2019-05-01 22:29 ` Eric Biggers
2019-05-02 5:52 ` Chandan Rajendra
2019-05-02 18:16 ` Eric Biggers
2019-04-28 4:31 ` [PATCH V2 11/13] ext4: Compute logical block and the page range to be encrypted Chandan Rajendra
2019-04-30 17:01 ` Eric Biggers
2019-05-01 14:11 ` Chandan Rajendra
2019-04-28 4:31 ` [PATCH V2 12/13] fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page Chandan Rajendra
2019-04-30 16:51 ` Eric Biggers
2019-05-01 14:22 ` Chandan Rajendra [this message]
2019-04-28 4:31 ` [PATCH V2 13/13] ext4: Enable encryption for subpage-sized blocks Chandan Rajendra
2019-04-30 0:27 ` [PATCH V2 00/13] Consolidate FS read I/O callbacks code Matthew Wilcox
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