fuse: add fusectl interface to max_background
Make the max_background and congestion_threshold parameters of a FUSE
mount tunable at runtime by adding the respective knobs to its directory
within the fusectl filesystem.
Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/control.c b/fs/fuse/control.c
index 218d514..3773fd6 100644
--- a/fs/fuse/control.c
+++ b/fs/fuse/control.c
@@ -61,6 +61,121 @@
return simple_read_from_buffer(buf, len, ppos, tmp, size);
}
+static ssize_t fuse_conn_limit_read(struct file *file, char __user *buf,
+ size_t len, loff_t *ppos, unsigned val)
+{
+ char tmp[32];
+ size_t size = sprintf(tmp, "%u\n", val);
+
+ return simple_read_from_buffer(buf, len, ppos, tmp, size);
+}
+
+static ssize_t fuse_conn_limit_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos, unsigned *val,
+ unsigned global_limit)
+{
+ unsigned long t;
+ char tmp[32];
+ unsigned limit = (1 << 16) - 1;
+ int err;
+
+ if (*ppos || count >= sizeof(tmp) - 1)
+ return -EINVAL;
+
+ if (copy_from_user(tmp, buf, count))
+ return -EINVAL;
+
+ tmp[count] = '\0';
+
+ err = strict_strtoul(tmp, 0, &t);
+ if (err)
+ return err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ limit = min(limit, global_limit);
+
+ if (t > limit)
+ return -EINVAL;
+
+ *val = t;
+
+ return count;
+}
+
+static ssize_t fuse_conn_max_background_read(struct file *file,
+ char __user *buf, size_t len,
+ loff_t *ppos)
+{
+ struct fuse_conn *fc;
+ unsigned val;
+
+ fc = fuse_ctl_file_conn_get(file);
+ if (!fc)
+ return 0;
+
+ val = fc->max_background;
+ fuse_conn_put(fc);
+
+ return fuse_conn_limit_read(file, buf, len, ppos, val);
+}
+
+static ssize_t fuse_conn_max_background_write(struct file *file,
+ const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned val;
+ ssize_t ret;
+
+ ret = fuse_conn_limit_write(file, buf, count, ppos, &val,
+ max_user_bgreq);
+ if (ret > 0) {
+ struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
+ if (fc) {
+ fc->max_background = val;
+ fuse_conn_put(fc);
+ }
+ }
+
+ return ret;
+}
+
+static ssize_t fuse_conn_congestion_threshold_read(struct file *file,
+ char __user *buf, size_t len,
+ loff_t *ppos)
+{
+ struct fuse_conn *fc;
+ unsigned val;
+
+ fc = fuse_ctl_file_conn_get(file);
+ if (!fc)
+ return 0;
+
+ val = fc->congestion_threshold;
+ fuse_conn_put(fc);
+
+ return fuse_conn_limit_read(file, buf, len, ppos, val);
+}
+
+static ssize_t fuse_conn_congestion_threshold_write(struct file *file,
+ const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned val;
+ ssize_t ret;
+
+ ret = fuse_conn_limit_write(file, buf, count, ppos, &val,
+ max_user_congthresh);
+ if (ret > 0) {
+ struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
+ if (fc) {
+ fc->congestion_threshold = val;
+ fuse_conn_put(fc);
+ }
+ }
+
+ return ret;
+}
+
static const struct file_operations fuse_ctl_abort_ops = {
.open = nonseekable_open,
.write = fuse_conn_abort_write,
@@ -71,6 +186,18 @@
.read = fuse_conn_waiting_read,
};
+static const struct file_operations fuse_conn_max_background_ops = {
+ .open = nonseekable_open,
+ .read = fuse_conn_max_background_read,
+ .write = fuse_conn_max_background_write,
+};
+
+static const struct file_operations fuse_conn_congestion_threshold_ops = {
+ .open = nonseekable_open,
+ .read = fuse_conn_congestion_threshold_read,
+ .write = fuse_conn_congestion_threshold_write,
+};
+
static struct dentry *fuse_ctl_add_dentry(struct dentry *parent,
struct fuse_conn *fc,
const char *name,
@@ -127,9 +254,14 @@
goto err;
if (!fuse_ctl_add_dentry(parent, fc, "waiting", S_IFREG | 0400, 1,
- NULL, &fuse_ctl_waiting_ops) ||
+ NULL, &fuse_ctl_waiting_ops) ||
!fuse_ctl_add_dentry(parent, fc, "abort", S_IFREG | 0200, 1,
- NULL, &fuse_ctl_abort_ops))
+ NULL, &fuse_ctl_abort_ops) ||
+ !fuse_ctl_add_dentry(parent, fc, "max_background", S_IFREG | 0600,
+ 1, NULL, &fuse_conn_max_background_ops) ||
+ !fuse_ctl_add_dentry(parent, fc, "congestion_threshold",
+ S_IFREG | 0600, 1, NULL,
+ &fuse_conn_congestion_threshold_ops))
goto err;
return 0;
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 6bcfab0..fc9c79f 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -32,7 +32,7 @@
#define FUSE_NAME_MAX 1024
/** Number of dentries for each connection in the control filesystem */
-#define FUSE_CTL_NUM_DENTRIES 3
+#define FUSE_CTL_NUM_DENTRIES 5
/** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
module will check permissions based on the file mode. Otherwise no
@@ -49,6 +49,10 @@
/** Global mutex protecting fuse_conn_list and the control filesystem */
extern struct mutex fuse_mutex;
+/** Module parameters */
+extern unsigned max_user_bgreq;
+extern unsigned max_user_congthresh;
+
/** FUSE inode */
struct fuse_inode {
/** Inode data */
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index e54ddbd..8f9aca8 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -31,7 +31,7 @@
static int set_global_limit(const char *val, struct kernel_param *kp);
-static unsigned max_user_bgreq;
+unsigned max_user_bgreq;
module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
&max_user_bgreq, 0644);
__MODULE_PARM_TYPE(max_user_bgreq, "uint");
@@ -39,7 +39,7 @@
"Global limit for the maximum number of backgrounded requests an "
"unprivileged user can set");
-static unsigned max_user_congthresh;
+unsigned max_user_congthresh;
module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
&max_user_congthresh, 0644);
__MODULE_PARM_TYPE(max_user_congthresh, "uint");