1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
6 * Allocation reservations function prototypes and structures.
8 * Copyright (C) 2010 Novell. All rights reserved.
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.
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.
20 #ifndef OCFS2_RESERVATIONS_H
21 #define OCFS2_RESERVATIONS_H
23 #include <linux/rbtree.h>
25 #define OCFS2_DEFAULT_RESV_LEVEL 2
26 #define OCFS2_MAX_RESV_LEVEL 9
27 #define OCFS2_MIN_RESV_LEVEL 0
29 struct ocfs2_alloc_reservation
{
30 struct rb_node r_node
;
32 unsigned int r_start
; /* Beginning of current window */
33 unsigned int r_len
; /* Length of the window */
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 */
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
48 struct ocfs2_reservation_map
{
49 struct rb_root m_reservations
;
52 struct ocfs2_super
*m_osb
;
54 /* The following are not initialized to meaningful values until a disk
55 * bitmap is provided. */
56 u32 m_bitmap_len
; /* Number of valid
59 struct list_head m_lru
; /* LRU of reservations
64 void ocfs2_resv_init_once(struct ocfs2_alloc_reservation
*resv
);
66 #define OCFS2_RESV_TYPES (OCFS2_RESV_FLAG_TMP|OCFS2_RESV_FLAG_DIR)
67 void ocfs2_resv_set_type(struct ocfs2_alloc_reservation
*resv
,
70 int ocfs2_dir_resv_allowed(struct ocfs2_super
*osb
);
73 * ocfs2_resv_discard() - truncate a reservation
75 * @resv: the reservation to truncate.
77 * After this function is called, the reservation will be empty, and
78 * unlinked from the rbtree.
80 void ocfs2_resv_discard(struct ocfs2_reservation_map
*resmap
,
81 struct ocfs2_alloc_reservation
*resv
);
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)
91 * Only possible return value other than '0' is -ENOMEM for failure to
92 * allocation mirror bitmap.
94 int ocfs2_resmap_init(struct ocfs2_super
*osb
,
95 struct ocfs2_reservation_map
*resmap
);
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.
103 * Re-initialize the parameters of a reservation bitmap. This is
104 * useful for local alloc window slides.
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.
110 void ocfs2_resmap_restart(struct ocfs2_reservation_map
*resmap
,
111 unsigned int clen
, char *disk_bitmap
);
114 * ocfs2_resmap_uninit() - uninitialize a reservation bitmap structure
115 * @resmap: the struct ocfs2_reservation_map to uninitialize
117 void ocfs2_resmap_uninit(struct ocfs2_reservation_map
*resmap
);
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
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.
131 * On success, zero is returned and the valid allocation area is set in cstart
134 * Returns -ENOSPC if reservations are disabled.
136 int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map
*resmap
,
137 struct ocfs2_alloc_reservation
*resv
,
138 int *cstart
, int *clen
);
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.
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().
155 void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map
*resmap
,
156 struct ocfs2_alloc_reservation
*resv
,
157 u32 cstart
, u32 clen
);
159 #endif /* OCFS2_RESERVATIONS_H */
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