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Diffstat (limited to 'fs/ocfs2/reservations.h')
| -rw-r--r-- | fs/ocfs2/reservations.h | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/fs/ocfs2/reservations.h b/fs/ocfs2/reservations.h new file mode 100644 index 000000000..42c2b804f --- /dev/null +++ b/fs/ocfs2/reservations.h @@ -0,0 +1,159 @@ +/* -*- mode: c; c-basic-offset: 8; -*- + * vim: noexpandtab sw=8 ts=8 sts=0: + * + * reservations.h + * + * Allocation reservations function prototypes and structures. + * + * Copyright (C) 2010 Novell. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +#ifndef OCFS2_RESERVATIONS_H +#define OCFS2_RESERVATIONS_H + +#include <linux/rbtree.h> + +#define OCFS2_DEFAULT_RESV_LEVEL 2 +#define OCFS2_MAX_RESV_LEVEL 9 +#define OCFS2_MIN_RESV_LEVEL 0 + +struct ocfs2_alloc_reservation { + struct rb_node r_node; + + unsigned int r_start; /* Beginning of current window */ + unsigned int r_len; /* Length of the window */ + + unsigned int r_last_len; /* Length of most recent alloc */ + unsigned int r_last_start; /* Start of most recent alloc */ + struct list_head r_lru; /* LRU list head */ + + unsigned int r_flags; +}; + +#define OCFS2_RESV_FLAG_INUSE 0x01 /* Set when r_node is part of a btree */ +#define OCFS2_RESV_FLAG_TMP 0x02 /* Temporary reservation, will be + * destroyed immedately after use */ +#define OCFS2_RESV_FLAG_DIR 0x04 /* Reservation is for an unindexed + * directory btree */ + +struct ocfs2_reservation_map { + struct rb_root m_reservations; + char *m_disk_bitmap; + + struct ocfs2_super *m_osb; + + /* The following are not initialized to meaningful values until a disk + * bitmap is provided. */ + u32 m_bitmap_len; /* Number of valid + * bits available */ + + struct list_head m_lru; /* LRU of reservations + * structures. */ + +}; + +void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv); + +#define OCFS2_RESV_TYPES (OCFS2_RESV_FLAG_TMP|OCFS2_RESV_FLAG_DIR) +void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv, + unsigned int flags); + +int ocfs2_dir_resv_allowed(struct ocfs2_super *osb); + +/** + * ocfs2_resv_discard() - truncate a reservation + * @resmap: + * @resv: the reservation to truncate. + * + * After this function is called, the reservation will be empty, and + * unlinked from the rbtree. + */ +void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap, + struct ocfs2_alloc_reservation *resv); + + +/** + * ocfs2_resmap_init() - Initialize fields of a reservations bitmap + * @resmap: struct ocfs2_reservation_map to initialize + * @obj: unused for now + * @ops: unused for now + * @max_bitmap_bytes: Maximum size of the bitmap (typically blocksize) + * + * Only possible return value other than '0' is -ENOMEM for failure to + * allocation mirror bitmap. + */ +int ocfs2_resmap_init(struct ocfs2_super *osb, + struct ocfs2_reservation_map *resmap); + +/** + * ocfs2_resmap_restart() - "restart" a reservation bitmap + * @resmap: reservations bitmap + * @clen: Number of valid bits in the bitmap + * @disk_bitmap: the disk bitmap this resmap should refer to. + * + * Re-initialize the parameters of a reservation bitmap. This is + * useful for local alloc window slides. + * + * This function will call ocfs2_trunc_resv against all existing + * reservations. A future version will recalculate existing + * reservations based on the new bitmap. + */ +void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap, + unsigned int clen, char *disk_bitmap); + +/** + * ocfs2_resmap_uninit() - uninitialize a reservation bitmap structure + * @resmap: the struct ocfs2_reservation_map to uninitialize + */ +void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap); + +/** + * ocfs2_resmap_resv_bits() - Return still-valid reservation bits + * @resmap: reservations bitmap + * @resv: reservation to base search from + * @cstart: start of proposed allocation + * @clen: length (in clusters) of proposed allocation + * + * Using the reservation data from resv, this function will compare + * resmap and resmap->m_disk_bitmap to determine what part (if any) of + * the reservation window is still clear to use. If resv is empty, + * this function will try to allocate a window for it. + * + * On success, zero is returned and the valid allocation area is set in cstart + * and clen. + * + * Returns -ENOSPC if reservations are disabled. + */ +int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap, + struct ocfs2_alloc_reservation *resv, + int *cstart, int *clen); + +/** + * ocfs2_resmap_claimed_bits() - Tell the reservation code that bits were used. + * @resmap: reservations bitmap + * @resv: optional reservation to recalulate based on new bitmap + * @cstart: start of allocation in clusters + * @clen: end of allocation in clusters. + * + * Tell the reservation code that bits were used to fulfill allocation in + * resmap. The bits don't have to have been part of any existing + * reservation. But we must always call this function when bits are claimed. + * Internally, the reservations code will use this information to mark the + * reservations bitmap. If resv is passed, it's next allocation window will be + * calculated. It also expects that 'cstart' is the same as we passed back + * from ocfs2_resmap_resv_bits(). + */ +void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap, + struct ocfs2_alloc_reservation *resv, + u32 cstart, u32 clen); + +#endif /* OCFS2_RESERVATIONS_H */ |