reservations.h

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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * reservations.h
 *
 * Allocation reservations function prototypes and structures.
 *
 * Copyright (C) 2010 Novell.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

#ifndef OCFS2_RESERVATIONS_H
#define OCFS2_RESERVATIONS_H

#include <linux/rbtree.h>

#define OCFS2_DEFAULT_RESV_LEVEL    2
#define OCFS2_MAX_RESV_LEVEL    9
#define OCFS2_MIN_RESV_LEVEL    0

struct ocfs2_alloc_reservation {
    struct rb_node  r_node;

    unsigned int    r_start;    /* Beginning of current window */
    unsigned int    r_len;      /* Length of the window */

    unsigned int    r_last_len; /* Length of most recent alloc */
    unsigned int    r_last_start;   /* Start of most recent alloc */
    struct list_head    r_lru;  /* LRU list head */

    unsigned int    r_flags;
};

#define OCFS2_RESV_FLAG_INUSE   0x01    /* Set when r_node is part of a btree */
#define OCFS2_RESV_FLAG_TMP 0x02    /* Temporary reservation, will be
                     * destroyed immedately after use */
#define OCFS2_RESV_FLAG_DIR 0x04    /* Reservation is for an unindexed
                     * directory btree */

struct ocfs2_reservation_map {
    struct rb_root      m_reservations;
    char            *m_disk_bitmap;

    struct ocfs2_super  *m_osb;

    /* The following are not initialized to meaningful values until a disk
     * bitmap is provided. */
    u32         m_bitmap_len;   /* Number of valid
                         * bits available */

    struct list_head    m_lru;      /* LRU of reservations
                         * structures. */

};

void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv);

#define OCFS2_RESV_TYPES    (OCFS2_RESV_FLAG_TMP|OCFS2_RESV_FLAG_DIR)
void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv,
             unsigned int flags);

int ocfs2_dir_resv_allowed(struct ocfs2_super *osb);

void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
            struct ocfs2_alloc_reservation *resv);


int ocfs2_resmap_init(struct ocfs2_super *osb,
              struct ocfs2_reservation_map *resmap);

void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
              unsigned int clen, char *disk_bitmap);

void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap);

int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
               struct ocfs2_alloc_reservation *resv,
               int *cstart, int *clen);

void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
                   struct ocfs2_alloc_reservation *resv,
                   u32 cstart, u32 clen);

#endif  /* OCFS2_RESERVATIONS_H */