Re: [PATCH v12 2/2] fuse: add default_request_timeout and max_request_timeout sysctls

Bernd Schubert
2025-01-23T14:41:32Z

On 1/23/25 15:28, Miklos Szeredi wrote:
> On Thu, 23 Jan 2025 at 10:21, Luis Henriques <luis@igalia.com> wrote:
>>
>> Hi Joanne,
>>
>> On Wed, Jan 22 2025, Joanne Koong wrote:
>>
>>> Introduce two new sysctls, "default_request_timeout" and
>>> "max_request_timeout". These control how long (in seconds) a server can
>>> take to reply to a request. If the server does not reply by the timeout,
>>> then the connection will be aborted. The upper bound on these sysctl
>>> values is 65535.
>>>
>>> "default_request_timeout" sets the default timeout if no timeout is
>>> specified by the fuse server on mount. 0 (default) indicates no default
>>> timeout should be enforced. If the server did specify a timeout, then
>>> default_request_timeout will be ignored.
>>>
>>> "max_request_timeout" sets the max amount of time the server may take to
>>> reply to a request. 0 (default) indicates no maximum timeout. If
>>> max_request_timeout is set and the fuse server attempts to set a
>>> timeout greater than max_request_timeout, the system will use
>>> max_request_timeout as the timeout. Similarly, if default_request_timeout
>>> is greater than max_request_timeout, the system will use
>>> max_request_timeout as the timeout. If the server does not request a
>>> timeout and default_request_timeout is set to 0 but max_request_timeout
>>> is set, then the timeout will be max_request_timeout.
>>>
>>> Please note that these timeouts are not 100% precise. The request may
>>> take roughly an extra FUSE_TIMEOUT_TIMER_FREQ seconds beyond the set max
>>> timeout due to how it's internally implemented.
>>>
>>> $ sysctl -a | grep fuse.default_request_timeout
>>> fs.fuse.default_request_timeout = 0
>>>
>>> $ echo 65536 | sudo tee /proc/sys/fs/fuse/default_request_timeout
>>> tee: /proc/sys/fs/fuse/default_request_timeout: Invalid argument
>>>
>>> $ echo 65535 | sudo tee /proc/sys/fs/fuse/default_request_timeout
>>> 65535
>>>
>>> $ sysctl -a | grep fuse.default_request_timeout
>>> fs.fuse.default_request_timeout = 65535
>>>
>>> $ echo 0 | sudo tee /proc/sys/fs/fuse/default_request_timeout
>>> 0
>>>
>>> $ sysctl -a | grep fuse.default_request_timeout
>>> fs.fuse.default_request_timeout = 0
>>>
>>> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
>>> Reviewed-by: Bernd Schubert <bschubert@ddn.com>
>>> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
>>> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
>
> Thanks, applied and pushed with some cleanups including Luis's clamp idea.

Hi Miklos,

I don't think the timeouts do work with io-uring yet, I'm not sure
yet if I have time to work on that today or tomorrow (on something
else right now, I can try, but no promises).

How shall we handle it, if I don't manage in time?

Thanks,
Bernd