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