1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2016 Oracle. All Rights Reserved.
4 * Author: Darrick J. Wong <darrick.wong@oracle.com>
5 */
6#ifndef __XFS_REFCOUNT_H__
7#define __XFS_REFCOUNT_H__
8
9struct xfs_trans;
10struct xfs_mount;
11struct xfs_perag;
12struct xfs_btree_cur;
13struct xfs_bmbt_irec;
14struct xfs_refcount_irec;
15
16extern int xfs_refcount_lookup_le(struct xfs_btree_cur *cur,
17 enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
18extern int xfs_refcount_lookup_ge(struct xfs_btree_cur *cur,
19 enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
20extern int xfs_refcount_lookup_eq(struct xfs_btree_cur *cur,
21 enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
22extern int xfs_refcount_get_rec(struct xfs_btree_cur *cur,
23 struct xfs_refcount_irec *irec, int *stat);
24
25static inline uint32_t
26xfs_refcount_encode_startblock(
27 xfs_agblock_t startblock,
28 enum xfs_refc_domain domain)
29{
30 uint32_t start;
31
32 /*
33 * low level btree operations need to handle the generic btree range
34 * query functions (which set rc_domain == -1U), so we check that the
35 * domain is /not/ shared.
36 */
37 start = startblock & ~XFS_REFC_COWFLAG;
38 if (domain != XFS_REFC_DOMAIN_SHARED)
39 start |= XFS_REFC_COWFLAG;
40
41 return start;
42}
43
44enum xfs_refcount_intent_type {
45 XFS_REFCOUNT_INCREASE = 1,
46 XFS_REFCOUNT_DECREASE,
47 XFS_REFCOUNT_ALLOC_COW,
48 XFS_REFCOUNT_FREE_COW,
49};
50
51struct xfs_refcount_intent {
52 struct list_head ri_list;
53 struct xfs_perag *ri_pag;
54 enum xfs_refcount_intent_type ri_type;
55 xfs_extlen_t ri_blockcount;
56 xfs_fsblock_t ri_startblock;
57};
58
59/* Check that the refcount is appropriate for the record domain. */
60static inline bool
61xfs_refcount_check_domain(
62 const struct xfs_refcount_irec *irec)
63{
64 if (irec->rc_domain == XFS_REFC_DOMAIN_COW && irec->rc_refcount != 1)
65 return false;
66 if (irec->rc_domain == XFS_REFC_DOMAIN_SHARED && irec->rc_refcount < 2)
67 return false;
68 return true;
69}
70
71void xfs_refcount_update_get_group(struct xfs_mount *mp,
72 struct xfs_refcount_intent *ri);
73
74void xfs_refcount_increase_extent(struct xfs_trans *tp,
75 struct xfs_bmbt_irec *irec);
76void xfs_refcount_decrease_extent(struct xfs_trans *tp,
77 struct xfs_bmbt_irec *irec);
78
79extern void xfs_refcount_finish_one_cleanup(struct xfs_trans *tp,
80 struct xfs_btree_cur *rcur, int error);
81extern int xfs_refcount_finish_one(struct xfs_trans *tp,
82 struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur);
83
84extern int xfs_refcount_find_shared(struct xfs_btree_cur *cur,
85 xfs_agblock_t agbno, xfs_extlen_t aglen, xfs_agblock_t *fbno,
86 xfs_extlen_t *flen, bool find_end_of_shared);
87
88void xfs_refcount_alloc_cow_extent(struct xfs_trans *tp, xfs_fsblock_t fsb,
89 xfs_extlen_t len);
90void xfs_refcount_free_cow_extent(struct xfs_trans *tp, xfs_fsblock_t fsb,
91 xfs_extlen_t len);
92extern int xfs_refcount_recover_cow_leftovers(struct xfs_mount *mp,
93 struct xfs_perag *pag);
94
95/*
96 * While we're adjusting the refcounts records of an extent, we have
97 * to keep an eye on the number of extents we're dirtying -- run too
98 * many in a single transaction and we'll exceed the transaction's
99 * reservation and crash the fs. Each record adds 12 bytes to the
100 * log (plus any key updates) so we'll conservatively assume 32 bytes
101 * per record. We must also leave space for btree splits on both ends
102 * of the range and space for the CUD and a new CUI.
103 *
104 * Each EFI that we attach to the transaction is assumed to consume ~32 bytes.
105 * This is a low estimate for an EFI tracking a single extent (16 bytes for the
106 * EFI header, 16 for the extent, and 12 for the xlog op header), but the
107 * estimate is acceptable if there's more than one extent being freed.
108 * In the worst case of freeing every other block during a refcount decrease
109 * operation, we amortize the space used for one EFI log item across 16
110 * extents.
111 */
112#define XFS_REFCOUNT_ITEM_OVERHEAD 32
113
114extern int xfs_refcount_has_records(struct xfs_btree_cur *cur,
115 enum xfs_refc_domain domain, xfs_agblock_t bno,
116 xfs_extlen_t len, enum xbtree_recpacking *outcome);
117union xfs_btree_rec;
118extern void xfs_refcount_btrec_to_irec(const union xfs_btree_rec *rec,
119 struct xfs_refcount_irec *irec);
120xfs_failaddr_t xfs_refcount_check_irec(struct xfs_perag *pag,
121 const struct xfs_refcount_irec *irec);
122extern int xfs_refcount_insert(struct xfs_btree_cur *cur,
123 struct xfs_refcount_irec *irec, int *stat);
124
125extern struct kmem_cache *xfs_refcount_intent_cache;
126
127int __init xfs_refcount_intent_init_cache(void);
128void xfs_refcount_intent_destroy_cache(void);
129
130typedef int (*xfs_refcount_query_range_fn)(
131 struct xfs_btree_cur *cur,
132 const struct xfs_refcount_irec *rec,
133 void *priv);
134
135int xfs_refcount_query_range(struct xfs_btree_cur *cur,
136 const struct xfs_refcount_irec *low_rec,
137 const struct xfs_refcount_irec *high_rec,
138 xfs_refcount_query_range_fn fn, void *priv);
139
140#endif /* __XFS_REFCOUNT_H__ */
141

source code of linux/fs/xfs/libxfs/xfs_refcount.h