Introduce two new sysctls, "default_request_timeout" and
"max_request_timeout". These control how long (in minutes) a server can
take to reply to a request. If the server does not reply by the timeout,
then the connection will be aborted.
"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 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@xxxxxxxxx>
Reviewed-by: Bernd Schubert <bschubert@xxxxxxx>
---
Documentation/admin-guide/sysctl/fs.rst | 27 +++++++++++++++++++++++++
fs/fuse/fuse_i.h | 10 +++++++++
fs/fuse/inode.c | 16 +++++++++++++--
fs/fuse/sysctl.c | 20 ++++++++++++++++++
4 files changed, 71 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/sysctl/fs.rst b/Documentation/admin-guide/sysctl/fs.rst
index fa25d7e718b3..790a34291467 100644
--- a/Documentation/admin-guide/sysctl/fs.rst
+++ b/Documentation/admin-guide/sysctl/fs.rst
@@ -342,3 +342,30 @@ 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 minutes) 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 a no-op (eg
+requests will not have a default request timeout set if no timeout was
+specified by the server).
+
+``/proc/sys/fs/fuse/max_request_timeout`` is a read/write file for
+setting/getting the maximum timeout (in minutes) 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 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 a no-op (eg requests will not have an upper bound on the
+timeout and if the server did not request a timeout and default_request_timeout
+was not set, there will be no timeout).
+
+Please note that for the timeout options, if the server does not respond to
+the request by the time the timeout elapses, then the connection to the fuse
+server will be aborted. Please also note that the timeouts are not 100%
+precise (eg you may set 10 minutes but the timeout may kick in after 11
+minutes).
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 9092201c4e0b..e82ddff8d752 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 minutes) 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 minutes) 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 ee006f09cd04..1e7cc6509e42 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,
@@ -1701,8 +1704,17 @@ 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 * 60, 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 * 60, HZ, &fc->timeout.req_timeout))
fc->timeout.req_timeout = ULONG_MAX;
timer_setup(&fc->timeout.timer, fuse_check_timeout, 0);
mod_timer(&fc->timeout.timer, jiffies + FUSE_TIMEOUT_TIMER_FREQ);
diff --git a/fs/fuse/sysctl.c b/fs/fuse/sysctl.c
index b272bb333005..6a9094e17950 100644
--- a/fs/fuse/sysctl.c
+++ b/fs/fuse/sysctl.c
@@ -13,6 +13,8 @@ static struct ctl_table_header *fuse_table_header;
/* Bound by fuse_init_out max_pages, which is a u16 */
static unsigned int sysctl_fuse_max_pages_limit = 65535;
+static unsigned int sysctl_fuse_max_req_timeout_limit = U16_MAX;
+
static struct ctl_table fuse_sysctl_table[] = {
{
.procname = "max_pages_limit",
@@ -23,6 +25,24 @@ 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_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = &sysctl_fuse_max_req_timeout_limit,
+ },
+ {
+ .procname = "max_request_timeout",
+ .data = &fuse_max_req_timeout,
+ .maxlen = sizeof(fuse_max_req_timeout),
+ .mode = 0644,
+ .proc_handler = proc_douintvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = &sysctl_fuse_max_req_timeout_limit,
+ },
};
int fuse_sysctl_register(void)
--
2.43.5
