quota.h

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/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Robert Elz at The University of Melbourne.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#ifndef _LINUX_QUOTA_
#define _LINUX_QUOTA_

#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/percpu_counter.h>

#include <linux/dqblk_xfs.h>
#include <linux/dqblk_v1.h>
#include <linux/dqblk_v2.h>

#include <linux/atomic.h>
#include <linux/uidgid.h>
#include <linux/projid.h>
#include <uapi/linux/quota.h>

#undef USRQUOTA
#undef GRPQUOTA
enum quota_type {
    USRQUOTA = 0,       /* element used for user quotas */
    GRPQUOTA = 1,       /* element used for group quotas */
    PRJQUOTA = 2,       /* element used for project quotas */
};

typedef __kernel_uid32_t qid_t; /* Type in which we store ids in memory */
typedef long long qsize_t;  /* Type in which we store sizes */

struct kqid {           /* Type in which we store the quota identifier */
    union {
        kuid_t uid;
        kgid_t gid;
        kprojid_t projid;
    };
    enum quota_type type;  /* USRQUOTA (uid) or GRPQUOTA (gid) or PRJQUOTA (projid) */
};

extern bool qid_eq(struct kqid left, struct kqid right);
extern bool qid_lt(struct kqid left, struct kqid right);
extern qid_t from_kqid(struct user_namespace *to, struct kqid qid);
extern qid_t from_kqid_munged(struct user_namespace *to, struct kqid qid);
extern bool qid_valid(struct kqid qid);

static inline struct kqid make_kqid(struct user_namespace *from,
                    enum quota_type type, qid_t qid)
{
    struct kqid kqid;

    kqid.type = type;
    switch (type) {
    case USRQUOTA:
        kqid.uid = make_kuid(from, qid);
        break;
    case GRPQUOTA:
        kqid.gid = make_kgid(from, qid);
        break;
    case PRJQUOTA:
        kqid.projid = make_kprojid(from, qid);
        break;
    default:
        BUG();
    }
    return kqid;
}

static inline struct kqid make_kqid_invalid(enum quota_type type)
{
    struct kqid kqid;

    kqid.type = type;
    switch (type) {
    case USRQUOTA:
        kqid.uid = INVALID_UID;
        break;
    case GRPQUOTA:
        kqid.gid = INVALID_GID;
        break;
    case PRJQUOTA:
        kqid.projid = INVALID_PROJID;
        break;
    default:
        BUG();
    }
    return kqid;
}

static inline struct kqid make_kqid_uid(kuid_t uid)
{
    struct kqid kqid;
    kqid.type = USRQUOTA;
    kqid.uid = uid;
    return kqid;
}

static inline struct kqid make_kqid_gid(kgid_t gid)
{
    struct kqid kqid;
    kqid.type = GRPQUOTA;
    kqid.gid = gid;
    return kqid;
}

static inline struct kqid make_kqid_projid(kprojid_t projid)
{
    struct kqid kqid;
    kqid.type = PRJQUOTA;
    kqid.projid = projid;
    return kqid;
}


extern spinlock_t dq_data_lock;

/* Maximal numbers of writes for quota operation (insert/delete/update)
 * (over VFS all formats) */
#define DQUOT_INIT_ALLOC max(V1_INIT_ALLOC, V2_INIT_ALLOC)
#define DQUOT_INIT_REWRITE max(V1_INIT_REWRITE, V2_INIT_REWRITE)
#define DQUOT_DEL_ALLOC max(V1_DEL_ALLOC, V2_DEL_ALLOC)
#define DQUOT_DEL_REWRITE max(V1_DEL_REWRITE, V2_DEL_REWRITE)

/*
 * Data for one user/group kept in memory
 */
struct mem_dqblk {
    qsize_t dqb_bhardlimit; /* absolute limit on disk blks alloc */
    qsize_t dqb_bsoftlimit; /* preferred limit on disk blks */
    qsize_t dqb_curspace;   /* current used space */
    qsize_t dqb_rsvspace;   /* current reserved space for delalloc*/
    qsize_t dqb_ihardlimit; /* absolute limit on allocated inodes */
    qsize_t dqb_isoftlimit; /* preferred inode limit */
    qsize_t dqb_curinodes;  /* current # allocated inodes */
    time_t dqb_btime;   /* time limit for excessive disk use */
    time_t dqb_itime;   /* time limit for excessive inode use */
};

/*
 * Data for one quotafile kept in memory
 */
struct quota_format_type;

struct mem_dqinfo {
    struct quota_format_type *dqi_format;
    int dqi_fmt_id;     /* Id of the dqi_format - used when turning
                 * quotas on after remount RW */
    struct list_head dqi_dirty_list;    /* List of dirty dquots */
    unsigned long dqi_flags;
    unsigned int dqi_bgrace;
    unsigned int dqi_igrace;
    qsize_t dqi_maxblimit;
    qsize_t dqi_maxilimit;
    void *dqi_priv;
};

struct super_block;

#define DQF_MASK 0xffff     /* Mask for format specific flags */
#define DQF_GETINFO_MASK 0x1ffff    /* Mask for flags passed to userspace */
#define DQF_SETINFO_MASK 0xffff     /* Mask for flags modifiable from userspace */
#define DQF_SYS_FILE_B      16
#define DQF_SYS_FILE (1 << DQF_SYS_FILE_B)  /* Quota file stored as system file */
#define DQF_INFO_DIRTY_B    31
#define DQF_INFO_DIRTY (1 << DQF_INFO_DIRTY_B)  /* Is info dirty? */

extern void mark_info_dirty(struct super_block *sb, int type);
static inline int info_dirty(struct mem_dqinfo *info)
{
    return test_bit(DQF_INFO_DIRTY_B, &info->dqi_flags);
}

enum {
    DQST_LOOKUPS,
    DQST_DROPS,
    DQST_READS,
    DQST_WRITES,
    DQST_CACHE_HITS,
    DQST_ALLOC_DQUOTS,
    DQST_FREE_DQUOTS,
    DQST_SYNCS,
    _DQST_DQSTAT_LAST
};

struct dqstats {
    int stat[_DQST_DQSTAT_LAST];
    struct percpu_counter counter[_DQST_DQSTAT_LAST];
};

extern struct dqstats *dqstats_pcpu;
extern struct dqstats dqstats;

static inline void dqstats_inc(unsigned int type)
{
    percpu_counter_inc(&dqstats.counter[type]);
}

static inline void dqstats_dec(unsigned int type)
{
    percpu_counter_dec(&dqstats.counter[type]);
}

#define DQ_MOD_B    0   /* dquot modified since read */
#define DQ_BLKS_B   1   /* uid/gid has been warned about blk limit */
#define DQ_INODES_B 2   /* uid/gid has been warned about inode limit */
#define DQ_FAKE_B   3   /* no limits only usage */
#define DQ_READ_B   4   /* dquot was read into memory */
#define DQ_ACTIVE_B 5   /* dquot is active (dquot_release not called) */
#define DQ_LASTSET_B    6   /* Following 6 bits (see QIF_) are reserved\
                 * for the mask of entries set via SETQUOTA\
                 * quotactl. They are set under dq_data_lock\
                 * and the quota format handling dquot can\
                 * clear them when it sees fit. */

struct dquot {
    struct hlist_node dq_hash;  /* Hash list in memory */
    struct list_head dq_inuse;  /* List of all quotas */
    struct list_head dq_free;   /* Free list element */
    struct list_head dq_dirty;  /* List of dirty dquots */
    struct mutex dq_lock;       /* dquot IO lock */
    atomic_t dq_count;      /* Use count */
    wait_queue_head_t dq_wait_unused;   /* Wait queue for dquot to become unused */
    struct super_block *dq_sb;  /* superblock this applies to */
    struct kqid dq_id;      /* ID this applies to (uid, gid, projid) */
    loff_t dq_off;          /* Offset of dquot on disk */
    unsigned long dq_flags;     /* See DQ_* */
    struct mem_dqblk dq_dqb;    /* Diskquota usage */
};

/* Operations which must be implemented by each quota format */
struct quota_format_ops {
    int (*check_quota_file)(struct super_block *sb, int type);  /* Detect whether file is in our format */
    int (*read_file_info)(struct super_block *sb, int type);    /* Read main info about file - called on quotaon() */
    int (*write_file_info)(struct super_block *sb, int type);   /* Write main info about file */
    int (*free_file_info)(struct super_block *sb, int type);    /* Called on quotaoff() */
    int (*read_dqblk)(struct dquot *dquot);     /* Read structure for one user */
    int (*commit_dqblk)(struct dquot *dquot);   /* Write structure for one user */
    int (*release_dqblk)(struct dquot *dquot);  /* Called when last reference to dquot is being dropped */
};

/* Operations working with dquots */
struct dquot_operations {
    int (*write_dquot) (struct dquot *);        /* Ordinary dquot write */
    struct dquot *(*alloc_dquot)(struct super_block *, int);    /* Allocate memory for new dquot */
    void (*destroy_dquot)(struct dquot *);      /* Free memory for dquot */
    int (*acquire_dquot) (struct dquot *);      /* Quota is going to be created on disk */
    int (*release_dquot) (struct dquot *);      /* Quota is going to be deleted from disk */
    int (*mark_dirty) (struct dquot *);     /* Dquot is marked dirty */
    int (*write_info) (struct super_block *, int);  /* Write of quota "superblock" */
    /* get reserved quota for delayed alloc, value returned is managed by
     * quota code only */
    qsize_t *(*get_reserved_space) (struct inode *);
};

struct path;

/* Operations handling requests from userspace */
struct quotactl_ops {
    int (*quota_on)(struct super_block *, int, int, struct path *);
    int (*quota_on_meta)(struct super_block *, int, int);
    int (*quota_off)(struct super_block *, int);
    int (*quota_sync)(struct super_block *, int);
    int (*get_info)(struct super_block *, int, struct if_dqinfo *);
    int (*set_info)(struct super_block *, int, struct if_dqinfo *);
    int (*get_dqblk)(struct super_block *, struct kqid, struct fs_disk_quota *);
    int (*set_dqblk)(struct super_block *, struct kqid, struct fs_disk_quota *);
    int (*get_xstate)(struct super_block *, struct fs_quota_stat *);
    int (*set_xstate)(struct super_block *, unsigned int, int);
};

struct quota_format_type {
    int qf_fmt_id;  /* Quota format id */
    const struct quota_format_ops *qf_ops;  /* Operations of format */
    struct module *qf_owner;        /* Module implementing quota format */
    struct quota_format_type *qf_next;
};

/* Quota state flags - they actually come in two flavors - for users and groups */
enum {
    _DQUOT_USAGE_ENABLED = 0,       /* Track disk usage for users */
    _DQUOT_LIMITS_ENABLED,          /* Enforce quota limits for users */
    _DQUOT_SUSPENDED,           /* User diskquotas are off, but
                         * we have necessary info in
                         * memory to turn them on */
    _DQUOT_STATE_FLAGS
};
#define DQUOT_USAGE_ENABLED (1 << _DQUOT_USAGE_ENABLED)
#define DQUOT_LIMITS_ENABLED    (1 << _DQUOT_LIMITS_ENABLED)
#define DQUOT_SUSPENDED     (1 << _DQUOT_SUSPENDED)
#define DQUOT_STATE_FLAGS   (DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED | \
                 DQUOT_SUSPENDED)
/* Other quota flags */
#define DQUOT_STATE_LAST    (_DQUOT_STATE_FLAGS * MAXQUOTAS)
#define DQUOT_QUOTA_SYS_FILE    (1 << DQUOT_STATE_LAST)
                        /* Quota file is a special
                         * system file and user cannot
                         * touch it. Filesystem is
                         * responsible for setting
                         * S_NOQUOTA, S_NOATIME flags
                         */
#define DQUOT_NEGATIVE_USAGE    (1 << (DQUOT_STATE_LAST + 1))
                           /* Allow negative quota usage */

static inline unsigned int dquot_state_flag(unsigned int flags, int type)
{
    return flags << _DQUOT_STATE_FLAGS * type;
}

static inline unsigned int dquot_generic_flag(unsigned int flags, int type)
{
    return (flags >> _DQUOT_STATE_FLAGS * type) & DQUOT_STATE_FLAGS;
}

#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
extern void quota_send_warning(struct kqid qid, dev_t dev,
                   const char warntype);
#else
static inline void quota_send_warning(struct kqid qid, dev_t dev,
                      const char warntype)
{
    return;
}
#endif /* CONFIG_QUOTA_NETLINK_INTERFACE */

struct quota_info {
    unsigned int flags;         /* Flags for diskquotas on this device */
    struct mutex dqio_mutex;        /* lock device while I/O in progress */
    struct mutex dqonoff_mutex;     /* Serialize quotaon & quotaoff */
    struct rw_semaphore dqptr_sem;      /* serialize ops using quota_info struct, pointers from inode to dquots */
    struct inode *files[MAXQUOTAS];     /* inodes of quotafiles */
    struct mem_dqinfo info[MAXQUOTAS];  /* Information for each quota type */
    const struct quota_format_ops *ops[MAXQUOTAS];  /* Operations for each type */
};

int register_quota_format(struct quota_format_type *fmt);
void unregister_quota_format(struct quota_format_type *fmt);

struct quota_module_name {
    int qm_fmt_id;
    char *qm_mod_name;
};

#define INIT_QUOTA_MODULE_NAMES {\
    {QFMT_VFS_OLD, "quota_v1"},\
    {QFMT_VFS_V0, "quota_v2"},\
    {0, NULL}}

#endif /* _QUOTA_ */