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1 /*
2  * mdt.h - NILFS meta data file prototype and definitions
3  *
4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will 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  * Written by Ryusuke Konishi.
17  */
18 
19 #ifndef _NILFS_MDT_H
20 #define _NILFS_MDT_H
21 
22 #include <linux/buffer_head.h>
23 #include <linux/blockgroup_lock.h>
24 #include "nilfs.h"
25 #include "page.h"
26 
27 /**
28  * struct nilfs_shadow_map - shadow mapping of meta data file
29  * @bmap_store: shadow copy of bmap state
30  * @frozen_data: shadowed dirty data pages
31  * @frozen_btnodes: shadowed dirty b-tree nodes' pages
32  * @frozen_buffers: list of frozen buffers
33  */
34 struct nilfs_shadow_map {
35 	struct nilfs_bmap_store bmap_store;
36 	struct address_space frozen_data;
37 	struct address_space frozen_btnodes;
38 	struct list_head frozen_buffers;
39 };
40 
41 /**
42  * struct nilfs_mdt_info - on-memory private data of meta data files
43  * @mi_sem: reader/writer semaphore for meta data operations
44  * @mi_bgl: per-blockgroup locking
45  * @mi_entry_size: size of an entry
46  * @mi_first_entry_offset: offset to the first entry
47  * @mi_entries_per_block: number of entries in a block
48  * @mi_palloc_cache: persistent object allocator cache
49  * @mi_shadow: shadow of bmap and page caches
50  * @mi_blocks_per_group: number of blocks in a group
51  * @mi_blocks_per_desc_block: number of blocks per descriptor block
52  */
53 struct nilfs_mdt_info {
54 	struct rw_semaphore	mi_sem;
55 	struct blockgroup_lock *mi_bgl;
56 	unsigned int		mi_entry_size;
57 	unsigned int		mi_first_entry_offset;
58 	unsigned long		mi_entries_per_block;
59 	struct nilfs_palloc_cache *mi_palloc_cache;
60 	struct nilfs_shadow_map *mi_shadow;
61 	unsigned long		mi_blocks_per_group;
62 	unsigned long		mi_blocks_per_desc_block;
63 };
64 
NILFS_MDT(const struct inode * inode)65 static inline struct nilfs_mdt_info *NILFS_MDT(const struct inode *inode)
66 {
67 	return inode->i_private;
68 }
69 
nilfs_is_metadata_file_inode(const struct inode * inode)70 static inline int nilfs_is_metadata_file_inode(const struct inode *inode)
71 {
72 	return inode->i_private != NULL;
73 }
74 
75 /* Default GFP flags using highmem */
76 #define NILFS_MDT_GFP      (__GFP_RECLAIM | __GFP_IO | __GFP_HIGHMEM)
77 
78 int nilfs_mdt_get_block(struct inode *, unsigned long, int,
79 			void (*init_block)(struct inode *,
80 					   struct buffer_head *, void *),
81 			struct buffer_head **);
82 int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
83 			 unsigned long end, unsigned long *blkoff,
84 			 struct buffer_head **out_bh);
85 int nilfs_mdt_delete_block(struct inode *, unsigned long);
86 int nilfs_mdt_forget_block(struct inode *, unsigned long);
87 int nilfs_mdt_fetch_dirty(struct inode *);
88 
89 int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz);
90 void nilfs_mdt_clear(struct inode *inode);
91 void nilfs_mdt_destroy(struct inode *inode);
92 
93 void nilfs_mdt_set_entry_size(struct inode *, unsigned int, unsigned int);
94 
95 int nilfs_mdt_setup_shadow_map(struct inode *inode,
96 			       struct nilfs_shadow_map *shadow);
97 int nilfs_mdt_save_to_shadow_map(struct inode *inode);
98 void nilfs_mdt_restore_from_shadow_map(struct inode *inode);
99 void nilfs_mdt_clear_shadow_map(struct inode *inode);
100 int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh);
101 struct buffer_head *nilfs_mdt_get_frozen_buffer(struct inode *inode,
102 						struct buffer_head *bh);
103 
nilfs_mdt_mark_dirty(struct inode * inode)104 static inline void nilfs_mdt_mark_dirty(struct inode *inode)
105 {
106 	if (!test_bit(NILFS_I_DIRTY, &NILFS_I(inode)->i_state))
107 		set_bit(NILFS_I_DIRTY, &NILFS_I(inode)->i_state);
108 }
109 
nilfs_mdt_clear_dirty(struct inode * inode)110 static inline void nilfs_mdt_clear_dirty(struct inode *inode)
111 {
112 	clear_bit(NILFS_I_DIRTY, &NILFS_I(inode)->i_state);
113 }
114 
nilfs_mdt_cno(struct inode * inode)115 static inline __u64 nilfs_mdt_cno(struct inode *inode)
116 {
117 	return ((struct the_nilfs *)inode->i_sb->s_fs_info)->ns_cno;
118 }
119 
120 static inline spinlock_t *
nilfs_mdt_bgl_lock(struct inode * inode,unsigned int block_group)121 nilfs_mdt_bgl_lock(struct inode *inode, unsigned int block_group)
122 {
123 	return bgl_lock_ptr(NILFS_MDT(inode)->mi_bgl, block_group);
124 }
125 
126 #endif /* _NILFS_MDT_H */
127