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Commit 9eead2a8 authored by Linus Torvalds's avatar Linus Torvalds
Browse files
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: add fusectl interface to max_background
  fuse: limit user-specified values of max background requests
  fuse: use drop_nlink() instead of direct nlink manipulation
  fuse: document protocol version negotiation
  fuse: make the number of max background requests and congestion threshold tunable
parents 6f130478 79a9d994
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+135 −3
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;
@@ -156,7 +288,7 @@ void fuse_ctl_remove_conn(struct fuse_conn *fc)
		d_drop(dentry);
		dput(dentry);
	}
	fuse_control_sb->s_root->d_inode->i_nlink--;
	drop_nlink(fuse_control_sb->s_root->d_inode);
}

static int fuse_ctl_fill_super(struct super_block *sb, void *data, int silent)
+5 −5
Original line number Diff line number Diff line
@@ -250,7 +250,7 @@ static void queue_request(struct fuse_conn *fc, struct fuse_req *req)

static void flush_bg_queue(struct fuse_conn *fc)
{
	while (fc->active_background < FUSE_MAX_BACKGROUND &&
	while (fc->active_background < fc->max_background &&
	       !list_empty(&fc->bg_queue)) {
		struct fuse_req *req;

@@ -280,11 +280,11 @@ __releases(&fc->lock)
	list_del(&req->intr_entry);
	req->state = FUSE_REQ_FINISHED;
	if (req->background) {
		if (fc->num_background == FUSE_MAX_BACKGROUND) {
		if (fc->num_background == fc->max_background) {
			fc->blocked = 0;
			wake_up_all(&fc->blocked_waitq);
		}
		if (fc->num_background == FUSE_CONGESTION_THRESHOLD &&
		if (fc->num_background == fc->congestion_threshold &&
		    fc->connected && fc->bdi_initialized) {
			clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
			clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
@@ -410,9 +410,9 @@ static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
{
	req->background = 1;
	fc->num_background++;
	if (fc->num_background == FUSE_MAX_BACKGROUND)
	if (fc->num_background == fc->max_background)
		fc->blocked = 1;
	if (fc->num_background == FUSE_CONGESTION_THRESHOLD &&
	if (fc->num_background == fc->congestion_threshold &&
	    fc->bdi_initialized) {
		set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
		set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
+11 −7
Original line number Diff line number Diff line
@@ -25,12 +25,6 @@
/** Max number of pages that can be used in a single read request */
#define FUSE_MAX_PAGES_PER_REQ 32

/** Maximum number of outstanding background requests */
#define FUSE_MAX_BACKGROUND 12

/** Congestion starts at 75% of maximum */
#define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100)

/** Bias for fi->writectr, meaning new writepages must not be sent */
#define FUSE_NOWRITE INT_MIN

@@ -38,7 +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
@@ -55,6 +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 */
@@ -349,6 +347,12 @@ struct fuse_conn {
	/** rbtree of fuse_files waiting for poll events indexed by ph */
	struct rb_root polled_files;

	/** Maximum number of outstanding background requests */
	unsigned max_background;

	/** Number of background requests at which congestion starts */
	unsigned congestion_threshold;

	/** Number of requests currently in the background */
	unsigned num_background;

+80 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/parser.h>
#include <linux/statfs.h>
#include <linux/random.h>
@@ -28,10 +29,34 @@ 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);

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");
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_PARM_TYPE(max_user_congthresh, "uint");
MODULE_PARM_DESC(max_user_congthresh,
 "Global limit for the maximum congestion threshold an "
 "unprivileged user can set");

#define FUSE_SUPER_MAGIC 0x65735546

#define FUSE_DEFAULT_BLKSIZE 512

/** Maximum number of outstanding background requests */
#define FUSE_DEFAULT_MAX_BACKGROUND 12

/** Congestion starts at 75% of maximum */
#define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)

struct fuse_mount_data {
	int fd;
	unsigned rootmode;
@@ -517,6 +542,8 @@ void fuse_conn_init(struct fuse_conn *fc)
	INIT_LIST_HEAD(&fc->bg_queue);
	INIT_LIST_HEAD(&fc->entry);
	atomic_set(&fc->num_waiting, 0);
	fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
	fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
	fc->khctr = 0;
	fc->polled_files = RB_ROOT;
	fc->reqctr = 0;
@@ -727,6 +754,54 @@ static const struct super_operations fuse_super_operations = {
	.show_options	= fuse_show_options,
};

static void sanitize_global_limit(unsigned *limit)
{
	if (*limit == 0)
		*limit = ((num_physpages << PAGE_SHIFT) >> 13) /
			 sizeof(struct fuse_req);

	if (*limit >= 1 << 16)
		*limit = (1 << 16) - 1;
}

static int set_global_limit(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);

	return 0;
}

static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
{
	int cap_sys_admin = capable(CAP_SYS_ADMIN);

	if (arg->minor < 13)
		return;

	sanitize_global_limit(&max_user_bgreq);
	sanitize_global_limit(&max_user_congthresh);

	if (arg->max_background) {
		fc->max_background = arg->max_background;

		if (!cap_sys_admin && fc->max_background > max_user_bgreq)
			fc->max_background = max_user_bgreq;
	}
	if (arg->congestion_threshold) {
		fc->congestion_threshold = arg->congestion_threshold;

		if (!cap_sys_admin &&
		    fc->congestion_threshold > max_user_congthresh)
			fc->congestion_threshold = max_user_congthresh;
	}
}

static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
{
	struct fuse_init_out *arg = &req->misc.init_out;
@@ -736,6 +811,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
	else {
		unsigned long ra_pages;

		process_init_limits(fc, arg);

		if (arg->minor >= 6) {
			ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
			if (arg->flags & FUSE_ASYNC_READ)
@@ -1150,6 +1227,9 @@ static int __init fuse_init(void)
	if (res)
		goto err_sysfs_cleanup;

	sanitize_global_limit(&max_user_bgreq);
	sanitize_global_limit(&max_user_congthresh);

	return 0;

 err_sysfs_cleanup:
+27 −2
Original line number Diff line number Diff line
@@ -30,6 +30,10 @@
 *  - add umask flag to input argument of open, mknod and mkdir
 *  - add notification messages for invalidation of inodes and
 *    directory entries
 *
 * 7.13
 *  - make max number of background requests and congestion threshold
 *    tunables
 */

#ifndef _LINUX_FUSE_H
@@ -37,11 +41,31 @@

#include <linux/types.h>

/*
 * Version negotiation:
 *
 * Both the kernel and userspace send the version they support in the
 * INIT request and reply respectively.
 *
 * If the major versions match then both shall use the smallest
 * of the two minor versions for communication.
 *
 * If the kernel supports a larger major version, then userspace shall
 * reply with the major version it supports, ignore the rest of the
 * INIT message and expect a new INIT message from the kernel with a
 * matching major version.
 *
 * If the library supports a larger major version, then it shall fall
 * back to the major protocol version sent by the kernel for
 * communication and reply with that major version (and an arbitrary
 * supported minor version).
 */

/** Version number of this interface */
#define FUSE_KERNEL_VERSION 7

/** Minor version number of this interface */
#define FUSE_KERNEL_MINOR_VERSION 12
#define FUSE_KERNEL_MINOR_VERSION 13

/** The node ID of the root inode */
#define FUSE_ROOT_ID 1
@@ -427,7 +451,8 @@ struct fuse_init_out {
	__u32	minor;
	__u32	max_readahead;
	__u32	flags;
	__u32	unused;
	__u16   max_background;
	__u16   congestion_threshold;
	__u32	max_write;
};