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linux-next/fs/gfs2/quota.h
Bob Peterson 2fba46a04c gfs2: Change inode qa_data to allow multiple users
Before this patch, multiple users called gfs2_qa_alloc which allocated
a qadata structure to the inode, if quotas are turned on. Later, in
file close or evict, the structure was deleted with gfs2_qa_delete.
But there can be several competing processes who need access to the
structure. There were races between file close (release) and the others.
Thus, a release could delete the structure out from under a process
that relied upon its existence. For example, chown.

This patch changes the management of the qadata structures to be
a get/put scheme. Function gfs2_qa_alloc has been changed to gfs2_qa_get
and if the structure is allocated, the count essentially starts out at
1. Function gfs2_qa_delete has been renamed to gfs2_qa_put, and the
last guy to decrement the count to 0 frees the memory.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-03-27 14:08:04 -05:00

66 lines
2.0 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*/
#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_qa_get(struct gfs2_inode *ip);
extern void gfs2_qa_put(struct gfs2_inode *ip);
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,
struct gfs2_alloc_parms *ap);
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_alloc_parms *ap)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
int ret;
ap->allowed = UINT_MAX; /* Assume we are permitted a whole lot */
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, ap);
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__ */