linux-ext4 - Re: [PATCH V3 6/7] Add decryption support for sub-pagesized blocks

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Message-Id: <3201150.UV5xBNPoiD@localhost.localdomain>
Date:   Tue, 25 Jun 2019 11:52:43 +0530
From:   Chandan Rajendra <chandan@...ux.ibm.com>
To:     Eric Biggers <ebiggers@...nel.org>
Cc:     linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-fscrypt@...r.kernel.org, tytso@....edu,
        adilger.kernel@...ger.ca, jaegeuk@...nel.org, yuchao0@...wei.com,
        hch@...radead.org
Subject: Re: [PATCH V3 6/7] Add decryption support for sub-pagesized blocks

On Saturday, June 22, 2019 2:59:17 AM IST Eric Biggers wrote:
> On Sun, Jun 16, 2019 at 09:38:12PM +0530, Chandan Rajendra wrote:
> > To support decryption of sub-pagesized blocks this commit adds code to,
> > 1. Track buffer head in "struct read_callbacks_ctx".
> > 2. Pass buffer head argument to all read callbacks.
> > 3. Add new fscrypt helper to decrypt the file data referred to by a
> >    buffer head.
> > 
> > Signed-off-by: Chandan Rajendra <chandan@...ux.ibm.com>
> > ---
> >  fs/buffer.c                    |  55 +++++++++------
> >  fs/crypto/bio.c                |  21 +++++-
> >  fs/f2fs/data.c                 |   2 +-
> >  fs/mpage.c                     |   2 +-
> >  fs/read_callbacks.c            | 118 +++++++++++++++++++++++++--------
> >  include/linux/buffer_head.h    |   1 +
> >  include/linux/read_callbacks.h |  13 +++-
> >  7 files changed, 158 insertions(+), 54 deletions(-)
> > 
> 
> This is another patch that unnecessarily changes way too many components at
> once.  My suggestions elsewhere would resolve this, though:
> 
> - This patch changes fs/f2fs/data.c and fs/mpage.c only to pass a NULL
>   buffer_head to read_callbacks_setup().  But as per my comments on patch 1,
>   read_callbacks_setup() should be split into read_callbacks_setup_bio() and
>   read_callbacks_end_bh().
> 
> - This patch changes fs/crypto/ only to add support for the buffer_head
>   decryption work.  But as per my comments on patch 1, that should be in
>   read_callbacks.c instead.
> 
> And adding buffer_head support to fs/read_callbacks.c should be its own patch,
> *or* should simply be folded into the patch that adds fs/read_callbacks.c.
> 
> Then the only thing remaining in this patch would be updating fs/buffer.c to
> make it use the read_callbacks, which should be retitled to something like
> "fs/buffer.c: add decryption support via read_callbacks".
> 

I agree.

-- 
chandan