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 | #endif /* __XFS_EXTFREE_ITEM_H__ */ |
92 | |