fuse: fix possible deadlock if rings are never initialized

When mounting a user-space filesystem using io_uring, the initialization
of the rings is done separately in the server side.  If for some reason
(e.g. a server bug) this step is not performed it will be impossible to
unmount the filesystem if there are already requests waiting.

This issue is easily reproduced with the libfuse passthrough_ll example,
if the queue depth is set to '0' and a request is queued before trying to
unmount the filesystem.  When trying to force the unmount, fuse_abort_conn()
will try to wake up all tasks waiting in fc->blocked_waitq, but because the
rings were never initialized, fuse_uring_ready() will never return 'true'.

Fixes: 3393ff964e0f ("fuse: block request allocation until io-uring init is complete")
Signed-off-by: Luis Henriques <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Acked-by: Miklos Szeredi <[email protected]>
Reviewed-by: Bernd Schubert <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

0 files changed, 0 insertions, 0 deletions