On Fri, Sep 04, 2020 at 12:05:23PM -0400, Jeff Layton wrote:
> CephFS will need to be able to generate a context for a new "prepared"
> inode. Add a new routine for getting the context out of an in-core
> inode.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/crypto/policy.c | 20 ++++++++++++++++++++
> include/linux/fscrypt.h | 1 +
> 2 files changed, 21 insertions(+)
>
> diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
> index c56ad886f7d7..10eddd113a21 100644
> --- a/fs/crypto/policy.c
> +++ b/fs/crypto/policy.c
> @@ -670,6 +670,26 @@ int fscrypt_set_context(struct inode *inode, void *fs_data)
> }
> EXPORT_SYMBOL_GPL(fscrypt_set_context);
>
> +/**
> + * fscrypt_context_from_inode() - fetch the encryption context out of in-core inode
Comment doesn't match the function name.
Also, the name isn't very clear. How about calling this
fscrypt_context_for_new_inode()?
BTW, I might rename fscrypt_new_context_from_policy() to
fscrypt_context_from_policy() in my patchset. Since it now makes the caller
provide the nonce, technically it's no longer limited to "new" contexts.
> + * @ctx: where context should be written
> + * @inode: inode from which to fetch context
> + *
> + * Given an in-core prepared, but not-necessarily fully-instantiated inode,
> + * generate an encryption context from its policy and write it to ctx.
Clarify what is meant by "prepared" (fscrypt_prepare_new_inode() was called)
vs. "instantiated".
> + *
> + * Returns size of the context.
> + */
> +int fscrypt_new_context_from_inode(union fscrypt_context *ctx, struct inode *inode)
> +{
> + struct fscrypt_info *ci = inode->i_crypt_info;
> +
> + BUILD_BUG_ON(sizeof(*ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE);
> +
> + return fscrypt_new_context_from_policy(ctx, &ci->ci_policy, ci->ci_nonce);
> +}
> +EXPORT_SYMBOL_GPL(fscrypt_new_context_from_inode);
fscrypt_set_context() should be changed to call this, instead of duplicating the
same logic. As part of that, the WARN_ON_ONCE(!ci) that's currently in
fscrypt_set_context() should go in here instead.
- Eric
