On Tue, Aug 10, 2021 at 3:12 PM Fengnan Chang [off-list ref] wrote:

Remove cache=always still have this problem, this problem is related
about FUSE_CAP_WRITEBACK_CACHE.

FUSE_CAP_WRITEBACK_CACHE by definition asks the kernel to trust its
own inode attributes. So I don't think we should fix its semantics.
Instead, in your case, it seems that the two mnts (PATHA and PATHB)
are not sharing the same superblock. I would suggest fixing it at a
higher level:
1. use bind-mount to mount PATHA and PATHB,
2. or add a `tag=xxx` argument to fuse mount option to uniquely
identify a fuse file system (just like we do in the virtiofs case)

Cheers,
Tao
-- 
Into Sth. Rich & Strange