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