1/*
2 * Copyright (c) 2000,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17 */
18#ifndef	__XFS_EXTFREE_ITEM_H__
19#define	__XFS_EXTFREE_ITEM_H__
20
21/* kernel only EFI/EFD definitions */
22
23struct xfs_mount;
24struct kmem_zone;
25
26/*
27 * Max number of extents in fast allocation path.
28 */
29#define	XFS_EFI_MAX_FAST_EXTENTS	16
30
31/*
32 * Define EFI flag bits. Manipulated by set/clear/test_bit operators.
33 */
34#define	XFS_EFI_RECOVERED	1
35
36/*
37 * This is the "extent free intention" log item.  It is used to log the fact
38 * that some extents need to be free.  It is used in conjunction with the
39 * "extent free done" log item described below.
40 *
41 * The EFI is reference counted so that it is not freed prior to both the EFI
42 * and EFD being committed and unpinned. This ensures the EFI is inserted into
43 * the AIL even in the event of out of order EFI/EFD processing. In other words,
44 * an EFI is born with two references:
45 *
46 * 	1.) an EFI held reference to track EFI AIL insertion
47 * 	2.) an EFD held reference to track EFD commit
48 *
49 * On allocation, both references are the responsibility of the caller. Once the
50 * EFI is added to and dirtied in a transaction, ownership of reference one
51 * transfers to the transaction. The reference is dropped once the EFI is
52 * inserted to the AIL or in the event of failure along the way (e.g., commit
53 * failure, log I/O error, etc.). Note that the caller remains responsible for
54 * the EFD reference under all circumstances to this point. The caller has no
55 * means to detect failure once the transaction is committed, however.
56 * Therefore, an EFD is required after this point, even in the event of
57 * unrelated failure.
58 *
59 * Once an EFD is allocated and dirtied in a transaction, reference two
60 * transfers to the transaction. The EFD reference is dropped once it reaches
61 * the unpin handler. Similar to the EFI, the reference also drops in the event
62 * of commit failure or log I/O errors. Note that the EFD is not inserted in the
63 * AIL, so at this point both the EFI and EFD are freed.
64 */
65typedef struct xfs_efi_log_item {
66	xfs_log_item_t		efi_item;
67	atomic_t		efi_refcount;
68	atomic_t		efi_next_extent;
69	unsigned long		efi_flags;	/* misc flags */
70	xfs_efi_log_format_t	efi_format;
71} xfs_efi_log_item_t;
72
73/*
74 * This is the "extent free done" log item.  It is used to log
75 * the fact that some extents earlier mentioned in an efi item
76 * have been freed.
77 */
78typedef struct xfs_efd_log_item {
79	xfs_log_item_t		efd_item;
80	xfs_efi_log_item_t	*efd_efip;
81	uint			efd_next_extent;
82	xfs_efd_log_format_t	efd_format;
83} xfs_efd_log_item_t;
84
85/*
86 * Max number of extents in fast allocation path.
87 */
88#define	XFS_EFD_MAX_FAST_EXTENTS	16
89
90extern struct kmem_zone	*xfs_efi_zone;
91extern struct kmem_zone	*xfs_efd_zone;
92
93xfs_efi_log_item_t	*xfs_efi_init(struct xfs_mount *, uint);
94xfs_efd_log_item_t	*xfs_efd_init(struct xfs_mount *, xfs_efi_log_item_t *,
95				      uint);
96int			xfs_efi_copy_format(xfs_log_iovec_t *buf,
97					    xfs_efi_log_format_t *dst_efi_fmt);
98void			xfs_efi_item_free(xfs_efi_log_item_t *);
99void			xfs_efi_release(struct xfs_efi_log_item *);
100
101#endif	/* __XFS_EXTFREE_ITEM_H__ */
102