Set default global limits for backgrounded requests and congestion
threshold considering the tunable maximum request size.
They are calculated using size of fuse_req structure, which is
variable due to it. This patch sets them according to the current
request size unless they are set via mod_param by the system
administrator.
Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@xxxxxxxxxxx>
Cc: Miklos Szeredi <miklos@xxxxxxxxxx>
Cc: Nikolaus Rath <Nikolaus@xxxxxxxx>
Cc: Liu Yuan <namei.unix@xxxxxxxxx>
Cc: Has-Wen Nienhuys <hanwen@xxxxxxxxx>
---
fs/fuse/fuse_i.h | 4 +++
fs/fuse/inode.c | 62 ++++++++++++++++++++++++++++++++++++++++++++----------
2 files changed, 55 insertions(+), 11 deletions(-)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 46df615..2dda6eb 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -27,6 +27,10 @@
/** Default number of pages that can be used in a single read/write request */
#define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32
+/** Maximum size of struct fuse_req */
+#define FUSE_CURRENT_REQ_SIZE (sizeof(struct fuse_req) +\
+ sysfs_max_req_pages * sizeof(struct page *))
+
/** Bias for fi->writectr, meaning new writepages must not be sent */
#define FUSE_NOWRITE INT_MIN
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 5f84a40..dc0302f 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -29,25 +29,36 @@ static struct kmem_cache *fuse_inode_cachep;
struct list_head fuse_conn_list;
DEFINE_MUTEX(fuse_mutex);
-static int set_global_limit(const char *val, struct kernel_param *kp);
+static int set_global_limit_bgreq(const char *val, struct kernel_param *kp);
+static int set_global_limit_thresh(const char *val, struct kernel_param *kp);
unsigned max_user_bgreq;
-module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
- &max_user_bgreq, 0644);
+module_param_call(max_user_bgreq, set_global_limit_bgreq,
+ param_get_uint, &max_user_bgreq, 0644);
__MODULE_PARM_TYPE(max_user_bgreq, "uint");
MODULE_PARM_DESC(max_user_bgreq,
"Global limit for the maximum number of backgrounded requests an "
"unprivileged user can set");
unsigned max_user_congthresh;
-module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
- &max_user_congthresh, 0644);
+module_param_call(max_user_congthresh, set_global_limit_thresh,
+ param_get_uint, &max_user_congthresh, 0644);
__MODULE_PARM_TYPE(max_user_congthresh, "uint");
MODULE_PARM_DESC(max_user_congthresh,
"Global limit for the maximum congestion threshold an "
"unprivileged user can set");
/**
+ * The flags below are used in order to distinguish how to set
+ * max_user_bgreq and max_user_congthresh, respectively. They
+ * should be used if they are set via mod_param. If not, we should
+ * check their current limitation using check_global_limit() any
+ * time due to the tunable read/write request size.
+ */
+static bool mod_param_set_flg_bgreq;
+static bool mod_param_set_flg_thresh;
+
+/**
* Maximum number of pages allocated for struct fuse_req.
* It can be changed via sysfs to arbitrary number between
* FUSE_DEFAULT_MAX_PAGES_PER_REQ and nr_pages equivalent
@@ -766,13 +777,39 @@ static void sanitize_global_limit(unsigned *limit)
{
if (*limit == 0)
*limit = ((num_physpages << PAGE_SHIFT) >> 13) /
- sizeof(struct fuse_req);
+ FUSE_CURRENT_REQ_SIZE;
if (*limit >= 1 << 16)
*limit = (1 << 16) - 1;
}
-static int set_global_limit(const char *val, struct kernel_param *kp)
+static void check_global_limit(unsigned *limit, bool mod_param_flg)
+{
+ if (!mod_param_flg) {
+ unsigned cur_global_limit = 0;
+
+ sanitize_global_limit(&cur_global_limit);
+ *limit = cur_global_limit;
+ }
+}
+
+static int set_global_limit_bgreq(const char *val, struct kernel_param *kp)
+{
+ int rv;
+
+ rv = param_set_uint(val, kp);
+ if (rv)
+ return rv;
+
+ sanitize_global_limit((unsigned *)kp->arg);
+
+ /* max_user_bgreq is set via mod_param */
+ mod_param_set_flg_bgreq = true;
+
+ return 0;
+}
+
+static int set_global_limit_thresh(const char *val, struct kernel_param *kp)
{
int rv;
@@ -782,6 +819,9 @@ static int set_global_limit(const char *val, struct kernel_param *kp)
sanitize_global_limit((unsigned *)kp->arg);
+ /* max_user_congthresh is set via mod_param */
+ mod_param_set_flg_thresh = true;
+
return 0;
}
@@ -801,8 +841,8 @@ static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
if (arg->minor < 13)
return;
- sanitize_global_limit(&max_user_bgreq);
- sanitize_global_limit(&max_user_congthresh);
+ check_global_limit(&max_user_bgreq, mod_param_set_flg_bgreq);
+ check_global_limit(&max_user_congthresh, mod_param_set_flg_thresh);
if (arg->max_background) {
fc->max_background = arg->max_background;
@@ -1309,8 +1349,8 @@ static int __init fuse_init(void)
if (res)
goto err_sysfs_cleanup;
- sanitize_global_limit(&max_user_bgreq);
- sanitize_global_limit(&max_user_congthresh);
+ check_global_limit(&max_user_bgreq, mod_param_set_flg_bgreq);
+ check_global_limit(&max_user_congthresh, mod_param_set_flg_thresh);
return 0;
--
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