xref: /linux/fs/xfs/libxfs/xfs_refcount.h (revision b477ff98d903618a1ab8247861f2ea6e70c0f0f8)
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 
9 struct xfs_trans;
10 struct xfs_mount;
11 struct xfs_perag;
12 struct xfs_btree_cur;
13 struct xfs_bmbt_irec;
14 struct xfs_refcount_irec;
15 struct xfs_rtgroup;
16 
17 extern int xfs_refcount_lookup_le(struct xfs_btree_cur *cur,
18 		enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
19 extern int xfs_refcount_lookup_ge(struct xfs_btree_cur *cur,
20 		enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
21 extern int xfs_refcount_lookup_eq(struct xfs_btree_cur *cur,
22 		enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
23 extern int xfs_refcount_get_rec(struct xfs_btree_cur *cur,
24 		struct xfs_refcount_irec *irec, int *stat);
25 
26 static inline uint32_t
xfs_refcount_encode_startblock(xfs_agblock_t startblock,enum xfs_refc_domain domain)27 xfs_refcount_encode_startblock(
28 	xfs_agblock_t		startblock,
29 	enum xfs_refc_domain	domain)
30 {
31 	uint32_t		start;
32 
33 	/*
34 	 * low level btree operations need to handle the generic btree range
35 	 * query functions (which set rc_domain == -1U), so we check that the
36 	 * domain is /not/ shared.
37 	 */
38 	start = startblock & ~XFS_REFC_COWFLAG;
39 	if (domain != XFS_REFC_DOMAIN_SHARED)
40 		start |= XFS_REFC_COWFLAG;
41 
42 	return start;
43 }
44 
45 enum xfs_refcount_intent_type {
46 	XFS_REFCOUNT_INCREASE = 1,
47 	XFS_REFCOUNT_DECREASE,
48 	XFS_REFCOUNT_ALLOC_COW,
49 	XFS_REFCOUNT_FREE_COW,
50 };
51 
52 #define XFS_REFCOUNT_INTENT_STRINGS \
53 	{ XFS_REFCOUNT_INCREASE,	"incr" }, \
54 	{ XFS_REFCOUNT_DECREASE,	"decr" }, \
55 	{ XFS_REFCOUNT_ALLOC_COW,	"alloc_cow" }, \
56 	{ XFS_REFCOUNT_FREE_COW,	"free_cow" }
57 
58 struct xfs_refcount_intent {
59 	struct list_head			ri_list;
60 	struct xfs_group			*ri_group;
61 	enum xfs_refcount_intent_type		ri_type;
62 	xfs_extlen_t				ri_blockcount;
63 	xfs_fsblock_t				ri_startblock;
64 	bool					ri_realtime;
65 };
66 
67 /* Check that the refcount is appropriate for the record domain. */
68 static inline bool
xfs_refcount_check_domain(const struct xfs_refcount_irec * irec)69 xfs_refcount_check_domain(
70 	const struct xfs_refcount_irec	*irec)
71 {
72 	if (irec->rc_domain == XFS_REFC_DOMAIN_COW && irec->rc_refcount != 1)
73 		return false;
74 	if (irec->rc_domain == XFS_REFC_DOMAIN_SHARED && irec->rc_refcount < 2)
75 		return false;
76 	return true;
77 }
78 
79 void xfs_refcount_increase_extent(struct xfs_trans *tp, bool isrt,
80 		struct xfs_bmbt_irec *irec);
81 void xfs_refcount_decrease_extent(struct xfs_trans *tp, bool isrt,
82 		struct xfs_bmbt_irec *irec);
83 
84 int xfs_refcount_finish_one(struct xfs_trans *tp,
85 		struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur);
86 int xfs_rtrefcount_finish_one(struct xfs_trans *tp,
87 		struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur);
88 
89 extern int xfs_refcount_find_shared(struct xfs_btree_cur *cur,
90 		xfs_agblock_t agbno, xfs_extlen_t aglen, xfs_agblock_t *fbno,
91 		xfs_extlen_t *flen, bool find_end_of_shared);
92 
93 void xfs_refcount_alloc_cow_extent(struct xfs_trans *tp, bool isrt,
94 		xfs_fsblock_t fsb, xfs_extlen_t len);
95 void xfs_refcount_free_cow_extent(struct xfs_trans *tp, bool isrt,
96 		xfs_fsblock_t fsb, xfs_extlen_t len);
97 int xfs_refcount_recover_cow_leftovers(struct xfs_group *xg);
98 
99 /*
100  * While we're adjusting the refcounts records of an extent, we have
101  * to keep an eye on the number of extents we're dirtying -- run too
102  * many in a single transaction and we'll exceed the transaction's
103  * reservation and crash the fs.  Each record adds 12 bytes to the
104  * log (plus any key updates) so we'll conservatively assume 32 bytes
105  * per record.  We must also leave space for btree splits on both ends
106  * of the range and space for the CUD and a new CUI.
107  *
108  * Each EFI that we attach to the transaction is assumed to consume ~32 bytes.
109  * This is a low estimate for an EFI tracking a single extent (16 bytes for the
110  * EFI header, 16 for the extent, and 12 for the xlog op header), but the
111  * estimate is acceptable if there's more than one extent being freed.
112  * In the worst case of freeing every other block during a refcount decrease
113  * operation, we amortize the space used for one EFI log item across 16
114  * extents.
115  */
116 #define XFS_REFCOUNT_ITEM_OVERHEAD	32
117 
118 extern int xfs_refcount_has_records(struct xfs_btree_cur *cur,
119 		enum xfs_refc_domain domain, xfs_agblock_t bno,
120 		xfs_extlen_t len, enum xbtree_recpacking *outcome);
121 union xfs_btree_rec;
122 extern void xfs_refcount_btrec_to_irec(const union xfs_btree_rec *rec,
123 		struct xfs_refcount_irec *irec);
124 xfs_failaddr_t xfs_refcount_check_irec(struct xfs_perag *pag,
125 		const struct xfs_refcount_irec *irec);
126 xfs_failaddr_t xfs_rtrefcount_check_irec(struct xfs_rtgroup *rtg,
127 		const struct xfs_refcount_irec *irec);
128 extern int xfs_refcount_insert(struct xfs_btree_cur *cur,
129 		struct xfs_refcount_irec *irec, int *stat);
130 
131 extern struct kmem_cache	*xfs_refcount_intent_cache;
132 
133 int __init xfs_refcount_intent_init_cache(void);
134 void xfs_refcount_intent_destroy_cache(void);
135 
136 typedef int (*xfs_refcount_query_range_fn)(
137 	struct xfs_btree_cur		*cur,
138 	const struct xfs_refcount_irec	*rec,
139 	void				*priv);
140 
141 int xfs_refcount_query_range(struct xfs_btree_cur *cur,
142 		const struct xfs_refcount_irec *low_rec,
143 		const struct xfs_refcount_irec *high_rec,
144 		xfs_refcount_query_range_fn fn, void *priv);
145 
146 #endif	/* __XFS_REFCOUNT_H__ */
147