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1 | /* |
2 | * the_nilfs.h - the_nilfs shared structure. | |
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 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | * | |
20 | * Written by Ryusuke Konishi <ryusuke@osrg.net> | |
21 | * | |
22 | */ | |
23 | ||
24 | #ifndef _THE_NILFS_H | |
25 | #define _THE_NILFS_H | |
26 | ||
27 | #include <linux/types.h> | |
28 | #include <linux/buffer_head.h> | |
29 | #include <linux/fs.h> | |
30 | #include <linux/blkdev.h> | |
31 | #include <linux/backing-dev.h> | |
32 | #include "sb.h" | |
33 | ||
34 | /* the_nilfs struct */ | |
35 | enum { | |
36 | THE_NILFS_INIT = 0, /* Information from super_block is set */ | |
37 | THE_NILFS_LOADED, /* Roll-back/roll-forward has done and | |
38 | the latest checkpoint was loaded */ | |
39 | THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ | |
40 | THE_NILFS_COND_NONGC_WRITE, /* Condition to wake up cleanerd */ | |
41 | }; | |
42 | ||
43 | /** | |
44 | * struct the_nilfs - struct to supervise multiple nilfs mount points | |
45 | * @ns_flags: flags | |
46 | * @ns_count: reference count | |
47 | * @ns_bdev: block device | |
48 | * @ns_bdi: backing dev info | |
49 | * @ns_writer: back pointer to writable nilfs_sb_info | |
50 | * @ns_sem: semaphore for shared states | |
51 | * @ns_writer_mutex: mutex protecting ns_writer attach/detach | |
52 | * @ns_writer_refcount: number of referrers on ns_writer | |
53 | * @ns_sbh: buffer head of the on-disk super block | |
54 | * @ns_sbp: pointer to the super block data | |
55 | * @ns_used_segments: list of full segments in volatile active state | |
56 | * @ns_supers: list of nilfs super block structs | |
57 | * @ns_seg_seq: segment sequence counter | |
58 | * @ns_segnum: index number of the latest full segment. | |
59 | * @ns_nextnum: index number of the full segment index to be used next | |
60 | * @ns_pseg_offset: offset of next partial segment in the current full segment | |
61 | * @ns_cno: next checkpoint number | |
62 | * @ns_ctime: write time of the last segment | |
63 | * @ns_nongc_ctime: write time of the last segment not for cleaner operation | |
64 | * @ns_ndirtyblks: Number of dirty data blocks | |
65 | * @ns_last_segment_lock: lock protecting fields for the latest segment | |
66 | * @ns_last_pseg: start block number of the latest segment | |
67 | * @ns_last_seq: sequence value of the latest segment | |
68 | * @ns_last_cno: checkpoint number of the latest segment | |
69 | * @ns_free_segments_count: counter of free segments | |
70 | * @ns_segctor_sem: segment constructor semaphore | |
71 | * @ns_dat: DAT file inode | |
72 | * @ns_cpfile: checkpoint file inode | |
73 | * @ns_sufile: segusage file inode | |
74 | * @ns_gc_dat: shadow inode of the DAT file inode for GC | |
75 | * @ns_gc_inodes: dummy inodes to keep live blocks | |
76 | * @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks | |
77 | * @ns_cleanerd_wq: wait queue for cleanerd | |
78 | * @ns_blocksize_bits: bit length of block size | |
79 | * @ns_nsegments: number of segments in filesystem | |
80 | * @ns_blocks_per_segment: number of blocks per segment | |
81 | * @ns_r_segments_percentage: reserved segments percentage | |
82 | * @ns_nrsvsegs: number of reserved segments | |
83 | * @ns_first_data_block: block number of first data block | |
84 | * @ns_inode_size: size of on-disk inode | |
85 | * @ns_first_ino: first not-special inode number | |
86 | * @ns_crc_seed: seed value of CRC32 calculation | |
87 | */ | |
88 | struct the_nilfs { | |
89 | unsigned long ns_flags; | |
90 | atomic_t ns_count; | |
91 | ||
92 | struct block_device *ns_bdev; | |
93 | struct backing_dev_info *ns_bdi; | |
94 | struct nilfs_sb_info *ns_writer; | |
95 | struct rw_semaphore ns_sem; | |
96 | struct mutex ns_writer_mutex; | |
97 | atomic_t ns_writer_refcount; | |
98 | ||
99 | /* | |
100 | * used for | |
101 | * - loading the latest checkpoint exclusively. | |
102 | * - allocating a new full segment. | |
103 | * - protecting s_dirt in the super_block struct | |
104 | * (see nilfs_write_super) and the following fields. | |
105 | */ | |
106 | struct buffer_head *ns_sbh; | |
107 | struct nilfs_super_block *ns_sbp; | |
108 | struct list_head ns_used_segments; | |
109 | unsigned ns_mount_state; | |
110 | struct list_head ns_supers; | |
111 | ||
112 | /* | |
113 | * Following fields are dedicated to a writable FS-instance. | |
114 | * Except for the period seeking checkpoint, code outside the segment | |
115 | * constructor must lock a segment semaphore with transaction_begin() | |
116 | * and transaction_end(), when accessing these fields. | |
117 | * The writable FS-instance is sole during a lifetime of the_nilfs. | |
118 | */ | |
119 | u64 ns_seg_seq; | |
120 | __u64 ns_segnum; | |
121 | __u64 ns_nextnum; | |
122 | unsigned long ns_pseg_offset; | |
123 | __u64 ns_cno; | |
124 | time_t ns_ctime; | |
125 | time_t ns_nongc_ctime; | |
126 | atomic_t ns_ndirtyblks; | |
127 | ||
128 | /* | |
129 | * The following fields hold information on the latest partial segment | |
130 | * written to disk with a super root. These fields are protected by | |
131 | * ns_last_segment_lock. | |
132 | */ | |
133 | spinlock_t ns_last_segment_lock; | |
134 | sector_t ns_last_pseg; | |
135 | u64 ns_last_seq; | |
136 | __u64 ns_last_cno; | |
137 | unsigned long ns_free_segments_count; | |
138 | ||
139 | struct rw_semaphore ns_segctor_sem; | |
140 | ||
141 | /* | |
142 | * Following fields are lock free except for the period before | |
143 | * the_nilfs is initialized. | |
144 | */ | |
145 | struct inode *ns_dat; | |
146 | struct inode *ns_cpfile; | |
147 | struct inode *ns_sufile; | |
148 | struct inode *ns_gc_dat; | |
149 | ||
150 | /* GC inode list and hash table head */ | |
151 | struct list_head ns_gc_inodes; | |
152 | struct hlist_head *ns_gc_inodes_h; | |
153 | ||
154 | /* cleanerd */ | |
155 | wait_queue_head_t ns_cleanerd_wq; | |
156 | ||
157 | /* Disk layout information (static) */ | |
158 | unsigned int ns_blocksize_bits; | |
159 | unsigned long ns_nsegments; | |
160 | unsigned long ns_blocks_per_segment; | |
161 | unsigned long ns_r_segments_percentage; | |
162 | unsigned long ns_nrsvsegs; | |
163 | unsigned long ns_first_data_block; | |
164 | int ns_inode_size; | |
165 | int ns_first_ino; | |
166 | u32 ns_crc_seed; | |
167 | }; | |
168 | ||
169 | #define NILFS_GCINODE_HASH_BITS 8 | |
170 | #define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS) | |
171 | ||
172 | #define THE_NILFS_FNS(bit, name) \ | |
173 | static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ | |
174 | { \ | |
175 | set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ | |
176 | } \ | |
177 | static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ | |
178 | { \ | |
179 | clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ | |
180 | } \ | |
181 | static inline int nilfs_##name(struct the_nilfs *nilfs) \ | |
182 | { \ | |
183 | return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ | |
184 | } | |
185 | ||
186 | THE_NILFS_FNS(INIT, init) | |
187 | THE_NILFS_FNS(LOADED, loaded) | |
188 | THE_NILFS_FNS(DISCONTINUED, discontinued) | |
189 | THE_NILFS_FNS(COND_NONGC_WRITE, cond_nongc_write) | |
190 | ||
191 | void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); | |
192 | struct the_nilfs *alloc_nilfs(struct block_device *); | |
193 | void put_nilfs(struct the_nilfs *); | |
194 | int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *); | |
195 | int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *); | |
196 | int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); | |
197 | void nilfs_dispose_used_segments(struct the_nilfs *); | |
198 | int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int); | |
199 | int nilfs_near_disk_full(struct the_nilfs *); | |
200 | ||
201 | ||
202 | static inline void get_nilfs(struct the_nilfs *nilfs) | |
203 | { | |
204 | /* Caller must have at least one reference of the_nilfs. */ | |
205 | atomic_inc(&nilfs->ns_count); | |
206 | } | |
207 | ||
208 | static inline struct nilfs_sb_info *nilfs_get_writer(struct the_nilfs *nilfs) | |
209 | { | |
210 | if (atomic_inc_and_test(&nilfs->ns_writer_refcount)) | |
211 | mutex_lock(&nilfs->ns_writer_mutex); | |
212 | return nilfs->ns_writer; | |
213 | } | |
214 | ||
215 | static inline void nilfs_put_writer(struct the_nilfs *nilfs) | |
216 | { | |
217 | if (atomic_add_negative(-1, &nilfs->ns_writer_refcount)) | |
218 | mutex_unlock(&nilfs->ns_writer_mutex); | |
219 | } | |
220 | ||
221 | static inline void | |
222 | nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) | |
223 | { | |
224 | mutex_lock(&nilfs->ns_writer_mutex); | |
225 | nilfs->ns_writer = sbi; | |
226 | mutex_unlock(&nilfs->ns_writer_mutex); | |
227 | } | |
228 | ||
229 | static inline void | |
230 | nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) | |
231 | { | |
232 | mutex_lock(&nilfs->ns_writer_mutex); | |
233 | if (sbi == nilfs->ns_writer) | |
234 | nilfs->ns_writer = NULL; | |
235 | mutex_unlock(&nilfs->ns_writer_mutex); | |
236 | } | |
237 | ||
238 | static inline void | |
239 | nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, | |
240 | sector_t *seg_start, sector_t *seg_end) | |
241 | { | |
242 | *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; | |
243 | *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; | |
244 | if (segnum == 0) | |
245 | *seg_start = nilfs->ns_first_data_block; | |
246 | } | |
247 | ||
248 | static inline sector_t | |
249 | nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) | |
250 | { | |
251 | return (segnum == 0) ? nilfs->ns_first_data_block : | |
252 | (sector_t)nilfs->ns_blocks_per_segment * segnum; | |
253 | } | |
254 | ||
255 | static inline __u64 | |
256 | nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) | |
257 | { | |
258 | sector_t segnum = blocknr; | |
259 | ||
260 | sector_div(segnum, nilfs->ns_blocks_per_segment); | |
261 | return segnum; | |
262 | } | |
263 | ||
264 | static inline void | |
265 | nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, | |
266 | sector_t seg_end) | |
267 | { | |
268 | /* terminate the current full segment (used in case of I/O-error) */ | |
269 | nilfs->ns_pseg_offset = seg_end - seg_start + 1; | |
270 | } | |
271 | ||
272 | static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) | |
273 | { | |
274 | /* move forward with a full segment */ | |
275 | nilfs->ns_segnum = nilfs->ns_nextnum; | |
276 | nilfs->ns_pseg_offset = 0; | |
277 | nilfs->ns_seg_seq++; | |
278 | } | |
279 | ||
280 | static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) | |
281 | { | |
282 | __u64 cno; | |
283 | ||
284 | spin_lock(&nilfs->ns_last_segment_lock); | |
285 | cno = nilfs->ns_last_cno; | |
286 | spin_unlock(&nilfs->ns_last_segment_lock); | |
287 | return cno; | |
288 | } | |
289 | ||
290 | #endif /* _THE_NILFS_H */ |