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[2a03:2880:25ff::face:b00c]) by smtp.gmail.com with ESMTPSA id 3f1490d57ef6-e470e54d912sm193050276.60.2024.12.13.18.29.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Dec 2024 18:29:38 -0800 (PST) From: Joanne Koong To: miklos@szeredi.hu, linux-fsdevel@vger.kernel.org Cc: josef@toxicpanda.com, bernd.schubert@fastmail.fm, jefflexu@linux.alibaba.com, laoar.shao@gmail.com, jlayton@kernel.org, senozhatsky@chromium.org, tfiga@chromium.org, bgeffon@google.com, etmartin4313@gmail.com, kernel-team@meta.com, Bernd Schubert Subject: [PATCH v10 2/2] fuse: add default_request_timeout and max_request_timeout sysctls Date: Fri, 13 Dec 2024 18:28:27 -0800 Message-ID: <20241214022827.1773071-3-joannelkoong@gmail.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20241214022827.1773071-1-joannelkoong@gmail.com> References: <20241214022827.1773071-1-joannelkoong@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 U32_MAX. "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 4294967296 | sudo tee /proc/sys/fs/fuse/default_request_timeout tee: /proc/sys/fs/fuse/default_request_timeout: Invalid argument $ echo 4294967295 | sudo tee /proc/sys/fs/fuse/default_request_timeout 4294967295 $ sysctl -a | grep fuse.default_request_timeout fs.fuse.default_request_timeout = 4294967295 $ 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 Reviewed-by: Bernd Schubert Reviewed-by: Josef Bacik --- Documentation/admin-guide/sysctl/fs.rst | 25 +++++++++++++++++++++++++ fs/fuse/fuse_i.h | 10 ++++++++++ fs/fuse/inode.c | 16 ++++++++++++++-- fs/fuse/sysctl.c | 14 ++++++++++++++ 4 files changed, 63 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/sysctl/fs.rst b/Documentation/admin-guide/sysctl/fs.rst index f5ec6c9312e1..12169a5e19dd 100644 --- a/Documentation/admin-guide/sysctl/fs.rst +++ b/Documentation/admin-guide/sysctl/fs.rst @@ -347,3 +347,28 @@ filesystems: ``/proc/sys/fs/fuse/max_pages_limit`` is a read/write file for setting/getting the maximum number of pages that can be used for servicing requests in FUSE. + +``/proc/sys/fs/fuse/default_request_timeout`` is a read/write file for +setting/getting the default timeout (in seconds) for a fuse server to +reply to a kernel-issued request in the event where the server did not +specify a timeout at mount. If the server set a timeout, +then default_request_timeout will be ignored. The default +"default_request_timeout" is set to 0. 0 indicates no default timeout. +The maximum value that can be set is U32_MAX. + +``/proc/sys/fs/fuse/max_request_timeout`` is a read/write file for +setting/getting the maximum timeout (in seconds) for a fuse server to +reply to a kernel-issued request. A value greater than 0 automatically opts +the server into a timeout that will be set to at most "max_request_timeout", +even if the server did not specify a timeout and default_request_timeout is +set to 0. If max_request_timeout is greater than 0 and the server set a timeout +greater than max_request_timeout or default_request_timeout is set to a value +greater than max_request_timeout, the system will use max_request_timeout as the +timeout. 0 indicates no max request timeout. The maximum value that can be set +is U32_MAX. + +For the timeouts, if the server does not respond to the request by the time +the set timeout elapses, then the connection to the fuse server will be aborted. +Please note that the timeouts are not 100% precise (eg you may set 60 seconds but +the timeout may kick in after 70 seconds). The upper margin of error for the +timeout is roughly FUSE_TIMEOUT_TIMER_FREQ seconds. diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 26eb00e5f043..310885b51087 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -46,6 +46,16 @@ /** Maximum of max_pages received in init_out */ extern unsigned int fuse_max_pages_limit; +/* + * Default timeout (in seconds) for the server to reply to a request + * before the connection is aborted, if no timeout was specified on mount. + */ +extern unsigned int fuse_default_req_timeout; +/* + * Max timeout (in seconds) for the server to reply to a request before + * the connection is aborted. + */ +extern unsigned int fuse_max_req_timeout; /** List of active connections */ extern struct list_head fuse_conn_list; diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 02dac88d922e..9f0be79eab74 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -36,6 +36,9 @@ DEFINE_MUTEX(fuse_mutex); static int set_global_limit(const char *val, const struct kernel_param *kp); unsigned int fuse_max_pages_limit = 256; +/* default is no timeout */ +unsigned int fuse_default_req_timeout = 0; +unsigned int fuse_max_req_timeout = 0; unsigned max_user_bgreq; module_param_call(max_user_bgreq, set_global_limit, param_get_uint, @@ -1733,8 +1736,17 @@ EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount); static void fuse_init_fc_timeout(struct fuse_conn *fc, struct fuse_fs_context *ctx) { - if (ctx->req_timeout) { - if (check_mul_overflow(ctx->req_timeout, HZ, &fc->timeout.req_timeout)) + unsigned int timeout = ctx->req_timeout ?: fuse_default_req_timeout; + + if (fuse_max_req_timeout) { + if (!timeout) + timeout = fuse_max_req_timeout; + else + timeout = min(timeout, fuse_max_req_timeout); + } + + if (timeout) { + if (check_mul_overflow(timeout, HZ, &fc->timeout.req_timeout)) fc->timeout.req_timeout = ULONG_MAX; INIT_DELAYED_WORK(&fc->timeout.work, fuse_check_timeout); diff --git a/fs/fuse/sysctl.c b/fs/fuse/sysctl.c index b272bb333005..5017059513f1 100644 --- a/fs/fuse/sysctl.c +++ b/fs/fuse/sysctl.c @@ -23,6 +23,20 @@ static struct ctl_table fuse_sysctl_table[] = { .extra1 = SYSCTL_ONE, .extra2 = &sysctl_fuse_max_pages_limit, }, + { + .procname = "default_request_timeout", + .data = &fuse_default_req_timeout, + .maxlen = sizeof(fuse_default_req_timeout), + .mode = 0644, + .proc_handler = proc_douintvec, + }, + { + .procname = "max_request_timeout", + .data = &fuse_max_req_timeout, + .maxlen = sizeof(fuse_max_req_timeout), + .mode = 0644, + .proc_handler = proc_douintvec, + }, }; int fuse_sysctl_register(void)