[linux-2.6-block.git] / fs / ocfs2 / reservations.h

/* SPDX-License-Identifier: GPL-2.0-only */
/* -*- 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.
 */

#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 */
Commit	Line	Data
1802d0be	1	/* SPDX-License-Identifier: GPL-2.0-only */
d02f00cc MF	2	/* -- mode: c; c-basic-offset: 8; --
	3	* vim: noexpandtab sw=8 ts=8 sts=0:
	4	*
	5	* reservations.h
	6	*
	7	* Allocation reservations function prototypes and structures.
	8	*
	9	* Copyright (C) 2010 Novell. All rights reserved.
d02f00cc MF	10	*/
	11
	12	#ifndef OCFS2_RESERVATIONS_H
	13	#define OCFS2_RESERVATIONS_H
	14
	15	#include <linux/rbtree.h>
	16
b07f8f24	17	#define OCFS2_DEFAULT_RESV_LEVEL 2
d02f00cc MF	18	#define OCFS2_MAX_RESV_LEVEL 9
	19	#define OCFS2_MIN_RESV_LEVEL 0
	20
	21	struct ocfs2_alloc_reservation {
	22	struct rb_node r_node;
	23
25985edc	24	unsigned int r_start; /* Beginning of current window */
d02f00cc MF	25	unsigned int r_len; /* Length of the window */
	26
	27	unsigned int r_last_len; /* Length of most recent alloc */
	28	unsigned int r_last_start; /* Start of most recent alloc */
	29	struct list_head r_lru; /* LRU list head */
	30
	31	unsigned int r_flags;
	32	};
	33
	34	#define OCFS2_RESV_FLAG_INUSE 0x01 /* Set when r_node is part of a btree */
	35	#define OCFS2_RESV_FLAG_TMP 0x02 /* Temporary reservation, will be
	36	* destroyed immedately after use */
e3b4a97d MF	37	#define OCFS2_RESV_FLAG_DIR 0x04 /* Reservation is for an unindexed
e3b4a97d MF	38	* directory btree */
d02f00cc MF	39
	40	struct ocfs2_reservation_map {
	41	struct rb_root m_reservations;
	42	char *m_disk_bitmap;
	43
	44	struct ocfs2_super *m_osb;
	45
	46	/* The following are not initialized to meaningful values until a disk
	47	* bitmap is provided. */
	48	u32 m_bitmap_len; /* Number of valid
	49	* bits available */
	50
	51	struct list_head m_lru; /* LRU of reservations
	52	* structures. */
	53
	54	};
	55
	56	void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv);
	57
e3b4a97d	58	#define OCFS2_RESV_TYPES (OCFS2_RESV_FLAG_TMP\|OCFS2_RESV_FLAG_DIR)
d02f00cc MF	59	void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv,
	60	unsigned int flags);
	61
83f92318 MF	62	int ocfs2_dir_resv_allowed(struct ocfs2_super *osb);
83f92318 MF	63
d02f00cc MF	64	/**
	65	* ocfs2_resv_discard() - truncate a reservation
	66	* @resmap:
	67	* @resv: the reservation to truncate.
	68	*
	69	* After this function is called, the reservation will be empty, and
	70	* unlinked from the rbtree.
	71	*/
	72	void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
	73	struct ocfs2_alloc_reservation *resv);
	74
	75
	76	/**
	77	* ocfs2_resmap_init() - Initialize fields of a reservations bitmap
	78	* @resmap: struct ocfs2_reservation_map to initialize
	79	* @obj: unused for now
	80	* @ops: unused for now
	81	* @max_bitmap_bytes: Maximum size of the bitmap (typically blocksize)
	82	*
	83	* Only possible return value other than '0' is -ENOMEM for failure to
	84	* allocation mirror bitmap.
	85	*/
	86	int ocfs2_resmap_init(struct ocfs2_super *osb,
	87	struct ocfs2_reservation_map *resmap);
	88
	89	/**
	90	* ocfs2_resmap_restart() - "restart" a reservation bitmap
	91	* @resmap: reservations bitmap
	92	* @clen: Number of valid bits in the bitmap
	93	* @disk_bitmap: the disk bitmap this resmap should refer to.
	94	*
	95	* Re-initialize the parameters of a reservation bitmap. This is
	96	* useful for local alloc window slides.
	97	*
	98	* This function will call ocfs2_trunc_resv against all existing
	99	* reservations. A future version will recalculate existing
	100	* reservations based on the new bitmap.
	101	*/
	102	void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
	103	unsigned int clen, char *disk_bitmap);
	104
	105	/**
	106	* ocfs2_resmap_uninit() - uninitialize a reservation bitmap structure
	107	* @resmap: the struct ocfs2_reservation_map to uninitialize
	108	*/
	109	void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap);
	110
	111	/**
	112	* ocfs2_resmap_resv_bits() - Return still-valid reservation bits
	113	* @resmap: reservations bitmap
	114	* @resv: reservation to base search from
	115	* @cstart: start of proposed allocation
	116	* @clen: length (in clusters) of proposed allocation
	117	*
	118	* Using the reservation data from resv, this function will compare
	119	* resmap and resmap->m_disk_bitmap to determine what part (if any) of
	120	* the reservation window is still clear to use. If resv is empty,
	121	* this function will try to allocate a window for it.
	122	*
	123	* On success, zero is returned and the valid allocation area is set in cstart
	124	* and clen.
	125	*
	126	* Returns -ENOSPC if reservations are disabled.
	127	*/
128	int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
129	struct ocfs2_alloc_reservation *resv,
130	int cstart, int clen);
131
132	/**
133	* ocfs2_resmap_claimed_bits() - Tell the reservation code that bits were used.
134	* @resmap: reservations bitmap
135	* @resv: optional reservation to recalulate based on new bitmap
136	* @cstart: start of allocation in clusters
137	* @clen: end of allocation in clusters.
138	*
139	* Tell the reservation code that bits were used to fulfill allocation in
140	* resmap. The bits don't have to have been part of any existing
141	* reservation. But we must always call this function when bits are claimed.
142	* Internally, the reservations code will use this information to mark the
143	* reservations bitmap. If resv is passed, it's next allocation window will be
b065556a TM	144	* calculated. It also expects that 'cstart' is the same as we passed back
b065556a TM	145	* from ocfs2_resmap_resv_bits().
d02f00cc MF	146	*/
	147	void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
	148	struct ocfs2_alloc_reservation *resv,
	149	u32 cstart, u32 clen);
	150
	151	#endif /* OCFS2_RESERVATIONS_H */