xref: /openbmc/linux/fs/xfs/libxfs/xfs_defer.h (revision d2ba09c1)
1 /*
2  * Copyright (C) 2016 Oracle.  All Rights Reserved.
3  *
4  * Author: Darrick J. Wong <darrick.wong@oracle.com>
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version 2
9  * of the License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it would be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write the Free Software Foundation,
18  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
19  */
20 #ifndef __XFS_DEFER_H__
21 #define	__XFS_DEFER_H__
22 
23 struct xfs_defer_op_type;
24 
25 /*
26  * Save a log intent item and a list of extents, so that we can replay
27  * whatever action had to happen to the extent list and file the log done
28  * item.
29  */
30 struct xfs_defer_pending {
31 	const struct xfs_defer_op_type	*dfp_type;	/* function pointers */
32 	struct list_head		dfp_list;	/* pending items */
33 	void				*dfp_intent;	/* log intent item */
34 	void				*dfp_done;	/* log done item */
35 	struct list_head		dfp_work;	/* work items */
36 	unsigned int			dfp_count;	/* # extent items */
37 };
38 
39 /*
40  * Header for deferred operation list.
41  *
42  * dop_low is used by the allocator to activate the lowspace algorithm -
43  * when free space is running low the extent allocator may choose to
44  * allocate an extent from an AG without leaving sufficient space for
45  * a btree split when inserting the new extent.  In this case the allocator
46  * will enable the lowspace algorithm which is supposed to allow further
47  * allocations (such as btree splits and newroots) to allocate from
48  * sequential AGs.  In order to avoid locking AGs out of order the lowspace
49  * algorithm will start searching for free space from AG 0.  If the correct
50  * transaction reservations have been made then this algorithm will eventually
51  * find all the space it needs.
52  */
53 enum xfs_defer_ops_type {
54 	XFS_DEFER_OPS_TYPE_BMAP,
55 	XFS_DEFER_OPS_TYPE_REFCOUNT,
56 	XFS_DEFER_OPS_TYPE_RMAP,
57 	XFS_DEFER_OPS_TYPE_FREE,
58 	XFS_DEFER_OPS_TYPE_MAX,
59 };
60 
61 #define XFS_DEFER_OPS_NR_INODES	2	/* join up to two inodes */
62 #define XFS_DEFER_OPS_NR_BUFS	2	/* join up to two buffers */
63 
64 struct xfs_defer_ops {
65 	bool			dop_committed;	/* did any trans commit? */
66 	bool			dop_low;	/* alloc in low mode */
67 	struct list_head	dop_intake;	/* unlogged pending work */
68 	struct list_head	dop_pending;	/* logged pending work */
69 
70 	/* relog these with each roll */
71 	struct xfs_inode	*dop_inodes[XFS_DEFER_OPS_NR_INODES];
72 	struct xfs_buf		*dop_bufs[XFS_DEFER_OPS_NR_BUFS];
73 };
74 
75 void xfs_defer_add(struct xfs_defer_ops *dop, enum xfs_defer_ops_type type,
76 		struct list_head *h);
77 int xfs_defer_finish(struct xfs_trans **tp, struct xfs_defer_ops *dop);
78 void xfs_defer_cancel(struct xfs_defer_ops *dop);
79 void xfs_defer_init(struct xfs_defer_ops *dop, xfs_fsblock_t *fbp);
80 bool xfs_defer_has_unfinished_work(struct xfs_defer_ops *dop);
81 int xfs_defer_ijoin(struct xfs_defer_ops *dop, struct xfs_inode *ip);
82 int xfs_defer_bjoin(struct xfs_defer_ops *dop, struct xfs_buf *bp);
83 
84 /* Description of a deferred type. */
85 struct xfs_defer_op_type {
86 	enum xfs_defer_ops_type	type;
87 	unsigned int		max_items;
88 	void (*abort_intent)(void *);
89 	void *(*create_done)(struct xfs_trans *, void *, unsigned int);
90 	int (*finish_item)(struct xfs_trans *, struct xfs_defer_ops *,
91 			struct list_head *, void *, void **);
92 	void (*finish_cleanup)(struct xfs_trans *, void *, int);
93 	void (*cancel_item)(struct list_head *);
94 	int (*diff_items)(void *, struct list_head *, struct list_head *);
95 	void *(*create_intent)(struct xfs_trans *, uint);
96 	void (*log_item)(struct xfs_trans *, void *, struct list_head *);
97 };
98 
99 void xfs_defer_init_op_type(const struct xfs_defer_op_type *type);
100 
101 #endif /* __XFS_DEFER_H__ */
102