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