1 /* -*- mode: c; c-basic-offset: 8; -*- 2 * vim: noexpandtab sw=8 ts=8 sts=0: 3 * 4 * reservations.h 5 * 6 * Allocation reservations function prototypes and structures. 7 * 8 * Copyright (C) 2010 Novell. All rights reserved. 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public 12 * License version 2 as published by the Free Software Foundation. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 */ 19 20 #ifndef OCFS2_RESERVATIONS_H 21 #define OCFS2_RESERVATIONS_H 22 23 #include <linux/rbtree.h> 24 25 #define OCFS2_DEFAULT_RESV_LEVEL 2 26 #define OCFS2_MAX_RESV_LEVEL 9 27 #define OCFS2_MIN_RESV_LEVEL 0 28 29 struct ocfs2_alloc_reservation { 30 struct rb_node r_node; 31 32 unsigned int r_start; /* Beginning of current window */ 33 unsigned int r_len; /* Length of the window */ 34 35 unsigned int r_last_len; /* Length of most recent alloc */ 36 unsigned int r_last_start; /* Start of most recent alloc */ 37 struct list_head r_lru; /* LRU list head */ 38 39 unsigned int r_flags; 40 }; 41 42 #define OCFS2_RESV_FLAG_INUSE 0x01 /* Set when r_node is part of a btree */ 43 #define OCFS2_RESV_FLAG_TMP 0x02 /* Temporary reservation, will be 44 * destroyed immedately after use */ 45 #define OCFS2_RESV_FLAG_DIR 0x04 /* Reservation is for an unindexed 46 * directory btree */ 47 48 struct ocfs2_reservation_map { 49 struct rb_root m_reservations; 50 char *m_disk_bitmap; 51 52 struct ocfs2_super *m_osb; 53 54 /* The following are not initialized to meaningful values until a disk 55 * bitmap is provided. */ 56 u32 m_bitmap_len; /* Number of valid 57 * bits available */ 58 59 struct list_head m_lru; /* LRU of reservations 60 * structures. */ 61 62 }; 63 64 void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv); 65 66 #define OCFS2_RESV_TYPES (OCFS2_RESV_FLAG_TMP|OCFS2_RESV_FLAG_DIR) 67 void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv, 68 unsigned int flags); 69 70 int ocfs2_dir_resv_allowed(struct ocfs2_super *osb); 71 72 /** 73 * ocfs2_resv_discard() - truncate a reservation 74 * @resmap: 75 * @resv: the reservation to truncate. 76 * 77 * After this function is called, the reservation will be empty, and 78 * unlinked from the rbtree. 79 */ 80 void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap, 81 struct ocfs2_alloc_reservation *resv); 82 83 84 /** 85 * ocfs2_resmap_init() - Initialize fields of a reservations bitmap 86 * @resmap: struct ocfs2_reservation_map to initialize 87 * @obj: unused for now 88 * @ops: unused for now 89 * @max_bitmap_bytes: Maximum size of the bitmap (typically blocksize) 90 * 91 * Only possible return value other than '0' is -ENOMEM for failure to 92 * allocation mirror bitmap. 93 */ 94 int ocfs2_resmap_init(struct ocfs2_super *osb, 95 struct ocfs2_reservation_map *resmap); 96 97 /** 98 * ocfs2_resmap_restart() - "restart" a reservation bitmap 99 * @resmap: reservations bitmap 100 * @clen: Number of valid bits in the bitmap 101 * @disk_bitmap: the disk bitmap this resmap should refer to. 102 * 103 * Re-initialize the parameters of a reservation bitmap. This is 104 * useful for local alloc window slides. 105 * 106 * This function will call ocfs2_trunc_resv against all existing 107 * reservations. A future version will recalculate existing 108 * reservations based on the new bitmap. 109 */ 110 void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap, 111 unsigned int clen, char *disk_bitmap); 112 113 /** 114 * ocfs2_resmap_uninit() - uninitialize a reservation bitmap structure 115 * @resmap: the struct ocfs2_reservation_map to uninitialize 116 */ 117 void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap); 118 119 /** 120 * ocfs2_resmap_resv_bits() - Return still-valid reservation bits 121 * @resmap: reservations bitmap 122 * @resv: reservation to base search from 123 * @cstart: start of proposed allocation 124 * @clen: length (in clusters) of proposed allocation 125 * 126 * Using the reservation data from resv, this function will compare 127 * resmap and resmap->m_disk_bitmap to determine what part (if any) of 128 * the reservation window is still clear to use. If resv is empty, 129 * this function will try to allocate a window for it. 130 * 131 * On success, zero is returned and the valid allocation area is set in cstart 132 * and clen. 133 * 134 * Returns -ENOSPC if reservations are disabled. 135 */ 136 int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap, 137 struct ocfs2_alloc_reservation *resv, 138 int *cstart, int *clen); 139 140 /** 141 * ocfs2_resmap_claimed_bits() - Tell the reservation code that bits were used. 142 * @resmap: reservations bitmap 143 * @resv: optional reservation to recalulate based on new bitmap 144 * @cstart: start of allocation in clusters 145 * @clen: end of allocation in clusters. 146 * 147 * Tell the reservation code that bits were used to fulfill allocation in 148 * resmap. The bits don't have to have been part of any existing 149 * reservation. But we must always call this function when bits are claimed. 150 * Internally, the reservations code will use this information to mark the 151 * reservations bitmap. If resv is passed, it's next allocation window will be 152 * calculated. It also expects that 'cstart' is the same as we passed back 153 * from ocfs2_resmap_resv_bits(). 154 */ 155 void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap, 156 struct ocfs2_alloc_reservation *resv, 157 u32 cstart, u32 clen); 158 159 #endif /* OCFS2_RESERVATIONS_H */ 160