Re: [PATCH v5 0/3] FUSE: Implement atomic lookup + open/create

[Miklos Szeredi <miklos@xxxxxxxxxx>]

On Thu, 19 May 2022 at 19:42, Bernd Schubert <bschubert@xxxxxxx> wrote:

> Can you help me a bit to understand what we should change? I had also
> already thought to merge CREATE_EXT and OPEN_ATOMIC - so agreed.
> Shall we make the other cases more visible?

Make it clear in the code flow if we are using the new request or the
old; e.g. rename current fuse_atomic_open() to fuse_open_nonatomic()
and do

static int fuse_open_atomic(...)
{
    ...
    args.opcode = FUSE_OPEN_ATOMIC;
    ...
    err = fuse_simple_request(...);
    if (err == -ENOSYS)
        goto fallback;
    ...
fallback:
    return fuse_open_nonatomic();
}

static int fuse_atomic_open(...)
{
    if (fc->no_open_atomic)
        return fuse_open_nonatomic();
    else
        return fuse_open_atomic();
}

Also we can tweak fuse_dentry_revalidate() so it always invalidates
negative dentries if the new atomic open is available, and possibly
for positive dentries as well, if the rfc patch makes it.

Thanks,
Miklos