linux-ext4 - Re: [PATCH 4/9] ext4: don't call fscrypt_get_encryption_info() from dx_show

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Date:   Wed, 2 Dec 2020 15:48:37 -0700
From:   Andreas Dilger <adilger@...ger.ca>
To:     Eric Biggers <ebiggers@...nel.org>
Cc:     linux-fscrypt@...r.kernel.org, linux-ext4@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-mtd@...ts.infradead.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 4/9] ext4: don't call fscrypt_get_encryption_info() from
 dx_show_leaf()

On Nov 24, 2020, at 5:23 PM, Eric Biggers <ebiggers@...nel.org> wrote:
> 
> From: Eric Biggers <ebiggers@...gle.com>
> 
> The call to fscrypt_get_encryption_info() in dx_show_leaf() is too low
> in the call tree; fscrypt_get_encryption_info() should have already been
> called when starting the directory operation.  And indeed, it already
> is.  Moreover, the encryption key is guaranteed to already be available
> because dx_show_leaf() is only called when adding a new directory entry.
> 
> And even if the key wasn't available, dx_show_leaf() uses
> fscrypt_fname_disk_to_usr() which knows how to create a no-key name.
> 
> So for the above reasons, and because it would be desirable to stop
> exporting fscrypt_get_encryption_info() directly to filesystems, remove
> the call to fscrypt_get_encryption_info() from dx_show_leaf().
> 
> Signed-off-by: Eric Biggers <ebiggers@...gle.com>

Reviewed-by: Andreas Dilger <adilger@...ger.ca>

> ---
> fs/ext4/namei.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index 793fc7db9d28..7b31aea3e025 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -643,13 +643,7 @@ static struct stats dx_show_leaf(struct inode *dir,
> 
> 				name  = de->name;
> 				len = de->name_len;
> -				if (IS_ENCRYPTED(dir))
> -					res = fscrypt_get_encryption_info(dir);
> -				if (res) {
> -					printk(KERN_WARNING "Error setting up"
> -					       " fname crypto: %d\n", res);
> -				}
> -				if (!fscrypt_has_encryption_key(dir)) {
> +				if (!IS_ENCRYPTED(dir)) {
> 					/* Directory is not encrypted */
> 					ext4fs_dirhash(dir, de->name,
> 						de->name_len, &h);
> --
> 2.29.2
> 


Cheers, Andreas






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