linux-ext4 - Re: [PATCH v2 1/5] fscrypt: clean up and improve dentry revalidation

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Message-ID: <20190417001041.GA18090@gmail.com>
Date:   Tue, 16 Apr 2019 17:10:42 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     Theodore Ts'o <tytso@....edu>
Cc:     linux-fscrypt@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
        linux-mtd@...ts.infradead.org, linux-unionfs@...r.kernel.org,
        Sarthak Kukreti <sarthakkukreti@...omium.org>,
        Gao Xiang <gaoxiang25@...wei.com>
Subject: Re: [PATCH v2 1/5] fscrypt: clean up and improve dentry revalidation

On Tue, Apr 16, 2019 at 07:08:40PM -0400, Theodore Ts'o wrote:
> On Wed, Mar 20, 2019 at 11:39:09AM -0700, Eric Biggers wrote:
> > From: Eric Biggers <ebiggers@...gle.com>
> > 
> > Make various improvements to fscrypt dentry revalidation:
> > 
> > - Don't try to handle the case where the per-directory key is removed,
> >   as this can't happen without the inode (and dentries) being evicted.
> > 
> > - Flag ciphertext dentries rather than plaintext dentries, since it's
> >   ciphertext dentries that need the special handling.
> > 
> > - Avoid doing unnecessary work for non-ciphertext dentries.
> > 
> > - When revalidating ciphertext dentries, try to set up the directory's
> >   i_crypt_info to make sure the key is really still absent, rather than
> >   invalidating all negative dentries as the previous code did.  An old
> >   comment suggested we can't do this for locking reasons, but AFAICT
> >   this comment was outdated and it actually works fine.
> > 
> > Signed-off-by: Eric Biggers <ebiggers@...gle.com>
> 
> Looks good, applied.
> 
> 					- Ted

Hi Ted, I assumed you resolved the conflict with "fscrypt: use READ_ONCE() to
access ->i_crypt_info"?  The code in fscrypt_d_revalidate() should be:

        dir = dget_parent(dentry);
        err = fscrypt_get_encryption_info(d_inode(dir));
        valid = !fscrypt_has_encryption_key(d_inode(dir));
        dput(dir);

- Eric