linux/fs/gfs2/quota.h
Steven Whitehouse c754fbbb1b GFS2: Use RCU/hlist_bl based hash for quotas
Prior to this patch, GFS2 kept all the quotas for each
super block in a single linked list. This is rather slow
when there are large numbers of quotas.

This patch introduces a hlist_bl based hash table, similar
to the one used for glocks. The initial look up of the quota
is now lockless in the case where it is already cached,
although we still have to take the per quota spinlock in
order to bump the ref count. Either way though, this is a
big improvement on what was there before.

The qd_lock and the per super block list is preserved, for
the time being. However it is intended that since this is no
longer used for its original role, it should be possible to
shrink the number of items on that list in due course and
remove the requirement to take qd_lock in qd_get.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-01-14 19:27:56 +00:00

63 lines
1.9 KiB
C

/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License version 2.
*/
#ifndef __QUOTA_DOT_H__
#define __QUOTA_DOT_H__
#include <linux/list_lru.h>
struct gfs2_inode;
struct gfs2_sbd;
#define NO_UID_QUOTA_CHANGE INVALID_UID
#define NO_GID_QUOTA_CHANGE INVALID_GID
extern int gfs2_quota_hold(struct gfs2_inode *ip, kuid_t uid, kgid_t gid);
extern void gfs2_quota_unhold(struct gfs2_inode *ip);
extern int gfs2_quota_lock(struct gfs2_inode *ip, kuid_t uid, kgid_t gid);
extern void gfs2_quota_unlock(struct gfs2_inode *ip);
extern int gfs2_quota_check(struct gfs2_inode *ip, kuid_t uid, kgid_t gid);
extern void gfs2_quota_change(struct gfs2_inode *ip, s64 change,
kuid_t uid, kgid_t gid);
extern int gfs2_quota_sync(struct super_block *sb, int type);
extern int gfs2_quota_refresh(struct gfs2_sbd *sdp, struct kqid qid);
extern int gfs2_quota_init(struct gfs2_sbd *sdp);
extern void gfs2_quota_cleanup(struct gfs2_sbd *sdp);
extern int gfs2_quotad(void *data);
extern void gfs2_wake_up_statfs(struct gfs2_sbd *sdp);
static inline int gfs2_quota_lock_check(struct gfs2_inode *ip)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
int ret;
if (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF)
return 0;
ret = gfs2_quota_lock(ip, NO_UID_QUOTA_CHANGE, NO_GID_QUOTA_CHANGE);
if (ret)
return ret;
if (sdp->sd_args.ar_quota != GFS2_QUOTA_ON)
return 0;
ret = gfs2_quota_check(ip, ip->i_inode.i_uid, ip->i_inode.i_gid);
if (ret)
gfs2_quota_unlock(ip);
return ret;
}
extern const struct quotactl_ops gfs2_quotactl_ops;
extern struct shrinker gfs2_qd_shrinker;
extern struct list_lru gfs2_qd_lru;
extern void __init gfs2_quota_hash_init(void);
#endif /* __QUOTA_DOT_H__ */