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 | |