1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000,2005 Silicon Graphics, Inc.
4  * All Rights Reserved.
5  */
6 #ifndef	__XFS_EXTFREE_ITEM_H__
7 #define	__XFS_EXTFREE_ITEM_H__
8 
9 /* kernel only EFI/EFD definitions */
10 
11 struct xfs_mount;
12 struct kmem_zone;
13 
14 /*
15  * Max number of extents in fast allocation path.
16  */
17 #define	XFS_EFI_MAX_FAST_EXTENTS	16
18 
19 /*
20  * Define EFI flag bits. Manipulated by set/clear/test_bit operators.
21  */
22 #define	XFS_EFI_RECOVERED	1
23 
24 /*
25  * This is the "extent free intention" log item.  It is used to log the fact
26  * that some extents need to be free.  It is used in conjunction with the
27  * "extent free done" log item described below.
28  *
29  * The EFI is reference counted so that it is not freed prior to both the EFI
30  * and EFD being committed and unpinned. This ensures the EFI is inserted into
31  * the AIL even in the event of out of order EFI/EFD processing. In other words,
32  * an EFI is born with two references:
33  *
34  * 	1.) an EFI held reference to track EFI AIL insertion
35  * 	2.) an EFD held reference to track EFD commit
36  *
37  * On allocation, both references are the responsibility of the caller. Once the
38  * EFI is added to and dirtied in a transaction, ownership of reference one
39  * transfers to the transaction. The reference is dropped once the EFI is
40  * inserted to the AIL or in the event of failure along the way (e.g., commit
41  * failure, log I/O error, etc.). Note that the caller remains responsible for
42  * the EFD reference under all circumstances to this point. The caller has no
43  * means to detect failure once the transaction is committed, however.
44  * Therefore, an EFD is required after this point, even in the event of
45  * unrelated failure.
46  *
47  * Once an EFD is allocated and dirtied in a transaction, reference two
48  * transfers to the transaction. The EFD reference is dropped once it reaches
49  * the unpin handler. Similar to the EFI, the reference also drops in the event
50  * of commit failure or log I/O errors. Note that the EFD is not inserted in the
51  * AIL, so at this point both the EFI and EFD are freed.
52  */
53 typedef struct xfs_efi_log_item {
54 	xfs_log_item_t		efi_item;
55 	atomic_t		efi_refcount;
56 	atomic_t		efi_next_extent;
57 	unsigned long		efi_flags;	/* misc flags */
58 	xfs_efi_log_format_t	efi_format;
59 } xfs_efi_log_item_t;
60 
61 /*
62  * This is the "extent free done" log item.  It is used to log
63  * the fact that some extents earlier mentioned in an efi item
64  * have been freed.
65  */
66 typedef struct xfs_efd_log_item {
67 	xfs_log_item_t		efd_item;
68 	xfs_efi_log_item_t	*efd_efip;
69 	uint			efd_next_extent;
70 	xfs_efd_log_format_t	efd_format;
71 } xfs_efd_log_item_t;
72 
73 /*
74  * Max number of extents in fast allocation path.
75  */
76 #define	XFS_EFD_MAX_FAST_EXTENTS	16
77 
78 extern struct kmem_zone	*xfs_efi_zone;
79 extern struct kmem_zone	*xfs_efd_zone;
80 
81 xfs_efi_log_item_t	*xfs_efi_init(struct xfs_mount *, uint);
82 xfs_efd_log_item_t	*xfs_efd_init(struct xfs_mount *, xfs_efi_log_item_t *,
83 				      uint);
84 int			xfs_efi_copy_format(xfs_log_iovec_t *buf,
85 					    xfs_efi_log_format_t *dst_efi_fmt);
86 void			xfs_efi_item_free(xfs_efi_log_item_t *);
87 void			xfs_efi_release(struct xfs_efi_log_item *);
88 
89 int			xfs_efi_recover(struct xfs_mount *mp,
90 					struct xfs_efi_log_item *efip);
91 
92 #endif	/* __XFS_EXTFREE_ITEM_H__ */
93