Eric Biggers <ebiggers@xxxxxxxxxx> writes:
> On Fri, Jan 19, 2024 at 03:47:36PM -0300, Gabriel Krisman Bertazi wrote:
>> /*
>> * When d_splice_alias() moves a directory's no-key alias to its plaintext alias
>> * as a result of the encryption key being added, DCACHE_NOKEY_NAME must be
>> * cleared. Note that we don't have to support arbitrary moves of this flag
>> * because fscrypt doesn't allow no-key names to be the source or target of a
>> * rename().
>> */
>> static inline void fscrypt_handle_d_move(struct dentry *dentry)
>> {
>> dentry->d_flags &= ~DCACHE_NOKEY_NAME;
>> +
>> + /*
>> + * Save the d_revalidate call cost during VFS operations. We
>> + * can do it because, when the key is available, the dentry
>> + * can't go stale and the key won't go away without eviction.
>> + */
>> + if (dentry->d_op && dentry->d_op->d_revalidate == fscrypt_d_revalidate)
>> + dentry->d_flags &= ~DCACHE_OP_REVALIDATE;
>> }
>
> Is there any way to optimize this further for the case where fscrypt is not
> being used? This is called unconditionally from d_move(). I've generally been
> trying to avoid things like this where the fscrypt support slows things down for
> everyone even when they're not using the feature.
The problem would be figuring out whether the filesystem has fscrypt
enabled. I think we can rely on sb->s_cop always being set:
if (sb->s_cop)
fscrypt_handle_d_move(dentry);
What do you think?
--
Gabriel Krisman Bertazi
