1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Persistent object (dat entry/disk inode) allocator/deallocator
4  *
5  * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
6  *
7  * Originally written by Koji Sato.
8  * Two allocators were unified by Ryusuke Konishi and Amagai Yoshiji.
9  */
10 
11 #ifndef _NILFS_ALLOC_H
12 #define _NILFS_ALLOC_H
13 
14 #include <linux/types.h>
15 #include <linux/buffer_head.h>
16 #include <linux/fs.h>
17 
18 /**
19  * nilfs_palloc_entries_per_group - get the number of entries per group
20  * @inode: inode of metadata file using this allocator
21  *
22  * The number of entries per group is defined by the number of bits
23  * that a bitmap block can maintain.
24  *
25  * Return: Number of entries per group.
26  */
27 static inline unsigned long
28 nilfs_palloc_entries_per_group(const struct inode *inode)
29 {
30 	return 1UL << (inode->i_blkbits + 3 /* log2(8 = CHAR_BITS) */);
31 }
32 
33 int nilfs_palloc_init_blockgroup(struct inode *, unsigned int);
34 int nilfs_palloc_get_entry_block(struct inode *, __u64, int,
35 				 struct buffer_head **);
36 size_t nilfs_palloc_entry_offset(const struct inode *inode, __u64 nr,
37 				 const struct buffer_head *bh);
38 
39 int nilfs_palloc_count_max_entries(struct inode *, u64, u64 *);
40 
41 /**
42  * struct nilfs_palloc_req - persistent allocator request and reply
43  * @pr_entry_nr: entry number (vblocknr or inode number)
44  * @pr_desc_bh: buffer head of the buffer containing block group descriptors
45  * @pr_bitmap_bh: buffer head of the buffer containing a block group bitmap
46  * @pr_entry_bh: buffer head of the buffer containing translation entries
47  */
48 struct nilfs_palloc_req {
49 	__u64 pr_entry_nr;
50 	struct buffer_head *pr_desc_bh;
51 	struct buffer_head *pr_bitmap_bh;
52 	struct buffer_head *pr_entry_bh;
53 };
54 
55 int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
56 				     struct nilfs_palloc_req *req, bool wrap);
57 void nilfs_palloc_commit_alloc_entry(struct inode *,
58 				     struct nilfs_palloc_req *);
59 void nilfs_palloc_abort_alloc_entry(struct inode *, struct nilfs_palloc_req *);
60 void nilfs_palloc_commit_free_entry(struct inode *, struct nilfs_palloc_req *);
61 int nilfs_palloc_prepare_free_entry(struct inode *, struct nilfs_palloc_req *);
62 void nilfs_palloc_abort_free_entry(struct inode *, struct nilfs_palloc_req *);
63 int nilfs_palloc_freev(struct inode *, __u64 *, size_t);
64 
65 #define nilfs_set_bit_atomic		ext2_set_bit_atomic
66 #define nilfs_clear_bit_atomic		ext2_clear_bit_atomic
67 #define nilfs_find_next_zero_bit	find_next_zero_bit_le
68 #define nilfs_find_next_bit		find_next_bit_le
69 
70 /**
71  * struct nilfs_bh_assoc - block offset and buffer head association
72  * @blkoff: block offset
73  * @bh: buffer head
74  */
75 struct nilfs_bh_assoc {
76 	unsigned long blkoff;
77 	struct buffer_head *bh;
78 };
79 
80 /**
81  * struct nilfs_palloc_cache - persistent object allocator cache
82  * @lock: cache protecting lock
83  * @prev_desc: blockgroup descriptors cache
84  * @prev_bitmap: blockgroup bitmap cache
85  * @prev_entry: translation entries cache
86  */
87 struct nilfs_palloc_cache {
88 	spinlock_t lock;
89 	struct nilfs_bh_assoc prev_desc;
90 	struct nilfs_bh_assoc prev_bitmap;
91 	struct nilfs_bh_assoc prev_entry;
92 };
93 
94 void nilfs_palloc_setup_cache(struct inode *inode,
95 			      struct nilfs_palloc_cache *cache);
96 void nilfs_palloc_clear_cache(struct inode *inode);
97 void nilfs_palloc_destroy_cache(struct inode *inode);
98 
99 #endif	/* _NILFS_ALLOC_H */
100