1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* -*- mode: c; c-basic-offset: 8; -*- 3 * vim: noexpandtab sw=8 ts=8 sts=0: 4 * 5 * reservations.h 6 * 7 * Allocation reservations function prototypes and structures. 8 * 9 * Copyright (C) 2010 Novell. All rights reserved. 10 */ 11 12 #ifndef OCFS2_RESERVATIONS_H 13 #define OCFS2_RESERVATIONS_H 14 15 #include <linux/rbtree.h> 16 17 #define OCFS2_DEFAULT_RESV_LEVEL 2 18 #define OCFS2_MAX_RESV_LEVEL 9 19 #define OCFS2_MIN_RESV_LEVEL 0 20 21 struct ocfs2_alloc_reservation { 22 struct rb_node r_node; 23 24 unsigned int r_start; /* Beginning of current window */ 25 unsigned int r_len; /* Length of the window */ 26 27 unsigned int r_last_len; /* Length of most recent alloc */ 28 unsigned int r_last_start; /* Start of most recent alloc */ 29 struct list_head r_lru; /* LRU list head */ 30 31 unsigned int r_flags; 32 }; 33 34 #define OCFS2_RESV_FLAG_INUSE 0x01 /* Set when r_node is part of a btree */ 35 #define OCFS2_RESV_FLAG_TMP 0x02 /* Temporary reservation, will be 36 * destroyed immedately after use */ 37 #define OCFS2_RESV_FLAG_DIR 0x04 /* Reservation is for an unindexed 38 * directory btree */ 39 40 struct ocfs2_reservation_map { 41 struct rb_root m_reservations; 42 char *m_disk_bitmap; 43 44 struct ocfs2_super *m_osb; 45 46 /* The following are not initialized to meaningful values until a disk 47 * bitmap is provided. */ 48 u32 m_bitmap_len; /* Number of valid 49 * bits available */ 50 51 struct list_head m_lru; /* LRU of reservations 52 * structures. */ 53 54 }; 55 56 void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv); 57 58 #define OCFS2_RESV_TYPES (OCFS2_RESV_FLAG_TMP|OCFS2_RESV_FLAG_DIR) 59 void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv, 60 unsigned int flags); 61 62 int ocfs2_dir_resv_allowed(struct ocfs2_super *osb); 63 64 /** 65 * ocfs2_resv_discard() - truncate a reservation 66 * @resmap: 67 * @resv: the reservation to truncate. 68 * 69 * After this function is called, the reservation will be empty, and 70 * unlinked from the rbtree. 71 */ 72 void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap, 73 struct ocfs2_alloc_reservation *resv); 74 75 76 /** 77 * ocfs2_resmap_init() - Initialize fields of a reservations bitmap 78 * @resmap: struct ocfs2_reservation_map to initialize 79 * @obj: unused for now 80 * @ops: unused for now 81 * @max_bitmap_bytes: Maximum size of the bitmap (typically blocksize) 82 * 83 * Only possible return value other than '0' is -ENOMEM for failure to 84 * allocation mirror bitmap. 85 */ 86 int ocfs2_resmap_init(struct ocfs2_super *osb, 87 struct ocfs2_reservation_map *resmap); 88 89 /** 90 * ocfs2_resmap_restart() - "restart" a reservation bitmap 91 * @resmap: reservations bitmap 92 * @clen: Number of valid bits in the bitmap 93 * @disk_bitmap: the disk bitmap this resmap should refer to. 94 * 95 * Re-initialize the parameters of a reservation bitmap. This is 96 * useful for local alloc window slides. 97 * 98 * This function will call ocfs2_trunc_resv against all existing 99 * reservations. A future version will recalculate existing 100 * reservations based on the new bitmap. 101 */ 102 void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap, 103 unsigned int clen, char *disk_bitmap); 104 105 /** 106 * ocfs2_resmap_uninit() - uninitialize a reservation bitmap structure 107 * @resmap: the struct ocfs2_reservation_map to uninitialize 108 */ 109 void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap); 110 111 /** 112 * ocfs2_resmap_resv_bits() - Return still-valid reservation bits 113 * @resmap: reservations bitmap 114 * @resv: reservation to base search from 115 * @cstart: start of proposed allocation 116 * @clen: length (in clusters) of proposed allocation 117 * 118 * Using the reservation data from resv, this function will compare 119 * resmap and resmap->m_disk_bitmap to determine what part (if any) of 120 * the reservation window is still clear to use. If resv is empty, 121 * this function will try to allocate a window for it. 122 * 123 * On success, zero is returned and the valid allocation area is set in cstart 124 * and clen. 125 * 126 * Returns -ENOSPC if reservations are disabled. 127 */ 128 int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap, 129 struct ocfs2_alloc_reservation *resv, 130 int *cstart, int *clen); 131 132 /** 133 * ocfs2_resmap_claimed_bits() - Tell the reservation code that bits were used. 134 * @resmap: reservations bitmap 135 * @resv: optional reservation to recalulate based on new bitmap 136 * @cstart: start of allocation in clusters 137 * @clen: end of allocation in clusters. 138 * 139 * Tell the reservation code that bits were used to fulfill allocation in 140 * resmap. The bits don't have to have been part of any existing 141 * reservation. But we must always call this function when bits are claimed. 142 * Internally, the reservations code will use this information to mark the 143 * reservations bitmap. If resv is passed, it's next allocation window will be 144 * calculated. It also expects that 'cstart' is the same as we passed back 145 * from ocfs2_resmap_resv_bits(). 146 */ 147 void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap, 148 struct ocfs2_alloc_reservation *resv, 149 u32 cstart, u32 clen); 150 151 #endif /* OCFS2_RESERVATIONS_H */ 152