Re: [PATCH] fuse: mark DAX inode releases as blocking

[Jingbo Xu <jefflexu@linux.alibaba.com>]

On 1/27/26 2:40 AM, Darrick J. Wong wrote:

> I wonder if fuse ought to grow the ability to whine when something is
> trying to issue a synchronous fuse command while running in a command
> queue completion context (aka the worker threads) but I don't know how
> difficult that would *really* be.

I had also observed similar issue where the FUSE daemon thread is
hanging in:

request_wait_answer
fuse_simple_request
fuse_flush_times
fuse write_inode
writeback_single_inode
write_inode_now
fuse_release
_fput

At that time I had no idea how FUSE daemon thread could trigger fuse
file release and thus I didn't dive into this further...

I think commit 26e5c67deb2e ("fuse: fix livelock in synchronous file put
from fuseblk workers") is not adequate in this case, as the commit only
makes FUSE_RELEASE request asynchronously, while in this case the daemon
thread can wait for FUSE_WRITE and FUSE_SETATTR.

Maybe the very first entry i.e. fuse_release() needs to be executed in
an asynchronous context (e.g. workqueue)...


-- 
Thanks,
Jingbo