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Commit 79a9d994 authored by Csaba Henk's avatar Csaba Henk Committed by Miklos Szeredi
Browse files

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: default avatarCsaba Henk <csaba@gluster.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent 487ea5af

fs/fuse/control.c

+134 −2
Original line number Diff line number Diff line
@@ -61,6 +61,121 @@ static ssize_t fuse_conn_waiting_read(struct file *file, char __user *buf, 
	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 @@ static const struct file_operations fuse_ctl_waiting_ops = { 
	.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,
@@ -129,7 +256,12 @@ int fuse_ctl_add_conn(struct fuse_conn *fc) 
	if (!fuse_ctl_add_dentry(parent, fc, "waiting", S_IFREG | 0400, 1,

				 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;

fs/fuse/fuse_i.h

+5 −1
Original line number Diff line number Diff line
@@ -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 @@ extern struct list_head fuse_conn_list; 
/** 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 */

fs/fuse/inode.c

+2 −2
Original line number Diff line number Diff line
@@ -31,7 +31,7 @@ DEFINE_MUTEX(fuse_mutex); 


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 @@ MODULE_PARM_DESC(max_user_bgreq, 
 "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");