Re: [PATCH v4 07/10] tmpfs: Add casefold lookup support

[André Almeida]

Hey Krisman,

Em 12/09/2024 16:04, Gabriel Krisman Bertazi escreveu:
> André Almeida <andrealmeid@xxxxxxxxxx> writes:

[...]

> > +#if IS_ENABLED(CONFIG_UNICODE)
> > +	if (ctx->encoding) {
> > +		sb->s_encoding = ctx->encoding;
> > +		sb->s_d_op = &shmem_ci_dentry_ops;
> > +		if (ctx->strict_encoding)
> > +			sb->s_encoding_flags = SB_ENC_STRICT_MODE_FL;
> > +	}
> >   #else
> > -	sb->s_flags |= SB_NOUSER;
> > +	sb->s_d_op = &simple_dentry_operations;
>
> Moving simple_dentry_operations to be set at s_d_op should be a separate
> patch.
>
> It is a change that has non-obvious side effects (i.e. the way we
> treat the root dentry) so it needs proper review by itself.  It is
> also not related to the rest of the case-insensitive patch.

The idea of setting simple_dentry_operations come from my previous 
approach of having our own shmem_lookup(), replacing simple_lookup(). 
Now that we are settled to keep with simple_lookup() anyway (that 
already sets simple_dentry_operations), I think we don't need this 
change anymore, right?

This will be set for every dentry that doesn't have a 
dentry->d_sb->s_d_op. Case-insensitive mount points will have this set, 
so we don't risk overwriting it.