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_cache;
13
14 /*
15 * Max number of extents in fast allocation path.
16 */
17 #define XFS_EFI_MAX_FAST_EXTENTS 16
18
19 /*
20 * This is the "extent free intention" log item. It is used to log the fact
21 * that some extents need to be free. It is used in conjunction with the
22 * "extent free done" log item described below.
23 *
24 * The EFI is reference counted so that it is not freed prior to both the EFI
25 * and EFD being committed and unpinned. This ensures the EFI is inserted into
26 * the AIL even in the event of out of order EFI/EFD processing. In other words,
27 * an EFI is born with two references:
28 *
29 * 1.) an EFI held reference to track EFI AIL insertion
30 * 2.) an EFD held reference to track EFD commit
31 *
32 * On allocation, both references are the responsibility of the caller. Once the
33 * EFI is added to and dirtied in a transaction, ownership of reference one
34 * transfers to the transaction. The reference is dropped once the EFI is
35 * inserted to the AIL or in the event of failure along the way (e.g., commit
36 * failure, log I/O error, etc.). Note that the caller remains responsible for
37 * the EFD reference under all circumstances to this point. The caller has no
38 * means to detect failure once the transaction is committed, however.
39 * Therefore, an EFD is required after this point, even in the event of
40 * unrelated failure.
41 *
42 * Once an EFD is allocated and dirtied in a transaction, reference two
43 * transfers to the transaction. The EFD reference is dropped once it reaches
44 * the unpin handler. Similar to the EFI, the reference also drops in the event
45 * of commit failure or log I/O errors. Note that the EFD is not inserted in the
46 * AIL, so at this point both the EFI and EFD are freed.
47 */
48 struct xfs_efi_log_item {
49 struct xfs_log_item efi_item;
50 atomic_t efi_refcount;
51 atomic_t efi_next_extent;
52 xfs_efi_log_format_t efi_format;
53 };
54
55 static inline size_t
56 xfs_efi_log_item_sizeof(
57 unsigned int nr)
58 {
59 return offsetof(struct xfs_efi_log_item, efi_format) +
60 xfs_efi_log_format_sizeof(nr);
61 }
62
63 /*
64 * This is the "extent free done" log item. It is used to log
65 * the fact that some extents earlier mentioned in an efi item
66 * have been freed.
67 */
68 struct xfs_efd_log_item {
69 struct xfs_log_item efd_item;
70 struct xfs_efi_log_item *efd_efip;
71 uint efd_next_extent;
72 xfs_efd_log_format_t efd_format;
73 };
74
75 static inline size_t
76 xfs_efd_log_item_sizeof(
77 unsigned int nr)
78 {
79 return offsetof(struct xfs_efd_log_item, efd_format) +
80 xfs_efd_log_format_sizeof(nr);
81 }
82
83 /*
84 * Max number of extents in fast allocation path.
85 */
86 #define XFS_EFD_MAX_FAST_EXTENTS 16
87
88 extern struct kmem_cache *xfs_efi_cache;
89 extern struct kmem_cache *xfs_efd_cache;
90
91 struct xfs_extent_free_item;
92
93 void xfs_extent_free_defer_add(struct xfs_trans *tp,
94 struct xfs_extent_free_item *xefi,
95 struct xfs_defer_pending **dfpp);
96
97 #endif /* __XFS_EXTFREE_ITEM_H__ */
98
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