Re: [PATCH v2] fuse: invalidate readdir cache on epoch bump

[Luis Henriques <luis@igalia.com>]

On Fri, May 15 2026, Joanne Koong wrote:

> On Fri, May 15, 2026 at 1:53 AM Luis Henriques <luis@igalia.com> wrote:
>>
>> On Thu, May 14 2026, Jun Wu wrote:
>>
>> > From: Jun Wu <quark@meta.com>
>> >
>> > FUSE_NOTIFY_INC_EPOCH invalidates dentries, but does not invalidate cached
>> > readdir results. A process with cwd inside a FUSE mount can therefore
>> > observe stale readdir(".") output after an epoch bump.
>> >
>> > Fix this by recording epoch in the readdir cache and checking it on reuse.
>> >
>> > Minimal reproducer:
>> >
>> > - mount a tiny FUSE fs with an empty root directory
>> > - on opendir, enable fi->cache_readdir and fi->keep_cache
>> > - chdir into the mount and call readdir(".") to populate readdir cache
>> > - make the FUSE server report one file in the root directory
>> > - send only FUSE_NOTIFY_INC_EPOCH
>> > - call readdir(".") again; before this change it stays stale, after this
>> >   change it sees the new file
>> >
>> > Fixes: 2396356a945b ("fuse: add more control over cache invalidation behaviour")
>> > Signed-off-by: Jun Wu <quark@meta.com>
>
> Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
>
> (btw, I think your v2 email may have gotten corrupted when sending. I
> wasn't able to find it in my inbox and had to manually import Luis's.
> I'm not seeing it show up on lore [1] either)

Hmm... yeah, looks like there's something funny with his email.  The mail
server I use seems to be more tolerant than lore regarding incorrect
email.  So maybe lore blocked it because the domain and the smtp server
address don't match...?  Anyway, maybe it's worth resending so that
everyone can see it.

Cheers,
-- 
Luís