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65b4643d RK |
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 */ | |
65b4643d RK |
40 | }; |
41 | ||
42 | /** | |
43 | * struct the_nilfs - struct to supervise multiple nilfs mount points | |
44 | * @ns_flags: flags | |
45 | * @ns_count: reference count | |
33c8e57c | 46 | * @ns_list: list head for nilfs_list |
65b4643d RK |
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 | |
e59399d0 | 51 | * @ns_super_sem: semaphore for global operations across super block instances |
aa7dfb89 | 52 | * @ns_mount_mutex: mutex protecting mount process of nilfs |
027d6404 | 53 | * @ns_writer_sem: semaphore protecting ns_writer attach/detach |
3f82ff55 | 54 | * @ns_current: back pointer to current mount |
e339ad31 RK |
55 | * @ns_sbh: buffer heads of on-disk super blocks |
56 | * @ns_sbp: pointers to super block data | |
57 | * @ns_sbwtime: previous write time of super blocks | |
58 | * @ns_sbsize: size of valid data in super block | |
65b4643d RK |
59 | * @ns_supers: list of nilfs super block structs |
60 | * @ns_seg_seq: segment sequence counter | |
61 | * @ns_segnum: index number of the latest full segment. | |
62 | * @ns_nextnum: index number of the full segment index to be used next | |
63 | * @ns_pseg_offset: offset of next partial segment in the current full segment | |
64 | * @ns_cno: next checkpoint number | |
65 | * @ns_ctime: write time of the last segment | |
66 | * @ns_nongc_ctime: write time of the last segment not for cleaner operation | |
67 | * @ns_ndirtyblks: Number of dirty data blocks | |
68 | * @ns_last_segment_lock: lock protecting fields for the latest segment | |
69 | * @ns_last_pseg: start block number of the latest segment | |
70 | * @ns_last_seq: sequence value of the latest segment | |
71 | * @ns_last_cno: checkpoint number of the latest segment | |
2c2e52fc | 72 | * @ns_prot_seq: least sequence number of segments which must not be reclaimed |
65b4643d RK |
73 | * @ns_free_segments_count: counter of free segments |
74 | * @ns_segctor_sem: segment constructor semaphore | |
75 | * @ns_dat: DAT file inode | |
76 | * @ns_cpfile: checkpoint file inode | |
77 | * @ns_sufile: segusage file inode | |
78 | * @ns_gc_dat: shadow inode of the DAT file inode for GC | |
79 | * @ns_gc_inodes: dummy inodes to keep live blocks | |
80 | * @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks | |
65b4643d RK |
81 | * @ns_blocksize_bits: bit length of block size |
82 | * @ns_nsegments: number of segments in filesystem | |
83 | * @ns_blocks_per_segment: number of blocks per segment | |
84 | * @ns_r_segments_percentage: reserved segments percentage | |
85 | * @ns_nrsvsegs: number of reserved segments | |
86 | * @ns_first_data_block: block number of first data block | |
87 | * @ns_inode_size: size of on-disk inode | |
88 | * @ns_first_ino: first not-special inode number | |
89 | * @ns_crc_seed: seed value of CRC32 calculation | |
90 | */ | |
91 | struct the_nilfs { | |
92 | unsigned long ns_flags; | |
93 | atomic_t ns_count; | |
33c8e57c | 94 | struct list_head ns_list; |
65b4643d RK |
95 | |
96 | struct block_device *ns_bdev; | |
97 | struct backing_dev_info *ns_bdi; | |
98 | struct nilfs_sb_info *ns_writer; | |
99 | struct rw_semaphore ns_sem; | |
e59399d0 | 100 | struct rw_semaphore ns_super_sem; |
aa7dfb89 | 101 | struct mutex ns_mount_mutex; |
027d6404 | 102 | struct rw_semaphore ns_writer_sem; |
65b4643d | 103 | |
e59399d0 RK |
104 | /* |
105 | * components protected by ns_super_sem | |
106 | */ | |
3f82ff55 | 107 | struct nilfs_sb_info *ns_current; |
e59399d0 | 108 | struct list_head ns_supers; |
3f82ff55 | 109 | |
65b4643d RK |
110 | /* |
111 | * used for | |
112 | * - loading the latest checkpoint exclusively. | |
113 | * - allocating a new full segment. | |
114 | * - protecting s_dirt in the super_block struct | |
115 | * (see nilfs_write_super) and the following fields. | |
116 | */ | |
e339ad31 RK |
117 | struct buffer_head *ns_sbh[2]; |
118 | struct nilfs_super_block *ns_sbp[2]; | |
119 | time_t ns_sbwtime[2]; | |
120 | unsigned ns_sbsize; | |
65b4643d | 121 | unsigned ns_mount_state; |
65b4643d RK |
122 | |
123 | /* | |
124 | * Following fields are dedicated to a writable FS-instance. | |
125 | * Except for the period seeking checkpoint, code outside the segment | |
47420c79 RK |
126 | * constructor must lock a segment semaphore while accessing these |
127 | * fields. | |
65b4643d RK |
128 | * The writable FS-instance is sole during a lifetime of the_nilfs. |
129 | */ | |
130 | u64 ns_seg_seq; | |
131 | __u64 ns_segnum; | |
132 | __u64 ns_nextnum; | |
133 | unsigned long ns_pseg_offset; | |
134 | __u64 ns_cno; | |
135 | time_t ns_ctime; | |
136 | time_t ns_nongc_ctime; | |
137 | atomic_t ns_ndirtyblks; | |
138 | ||
139 | /* | |
140 | * The following fields hold information on the latest partial segment | |
141 | * written to disk with a super root. These fields are protected by | |
142 | * ns_last_segment_lock. | |
143 | */ | |
144 | spinlock_t ns_last_segment_lock; | |
145 | sector_t ns_last_pseg; | |
146 | u64 ns_last_seq; | |
147 | __u64 ns_last_cno; | |
2c2e52fc | 148 | u64 ns_prot_seq; |
65b4643d RK |
149 | unsigned long ns_free_segments_count; |
150 | ||
151 | struct rw_semaphore ns_segctor_sem; | |
152 | ||
153 | /* | |
154 | * Following fields are lock free except for the period before | |
155 | * the_nilfs is initialized. | |
156 | */ | |
157 | struct inode *ns_dat; | |
158 | struct inode *ns_cpfile; | |
159 | struct inode *ns_sufile; | |
160 | struct inode *ns_gc_dat; | |
161 | ||
162 | /* GC inode list and hash table head */ | |
163 | struct list_head ns_gc_inodes; | |
164 | struct hlist_head *ns_gc_inodes_h; | |
165 | ||
65b4643d RK |
166 | /* Disk layout information (static) */ |
167 | unsigned int ns_blocksize_bits; | |
168 | unsigned long ns_nsegments; | |
169 | unsigned long ns_blocks_per_segment; | |
170 | unsigned long ns_r_segments_percentage; | |
171 | unsigned long ns_nrsvsegs; | |
172 | unsigned long ns_first_data_block; | |
173 | int ns_inode_size; | |
174 | int ns_first_ino; | |
175 | u32 ns_crc_seed; | |
176 | }; | |
177 | ||
178 | #define NILFS_GCINODE_HASH_BITS 8 | |
179 | #define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS) | |
180 | ||
181 | #define THE_NILFS_FNS(bit, name) \ | |
182 | static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ | |
183 | { \ | |
184 | set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ | |
185 | } \ | |
186 | static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ | |
187 | { \ | |
188 | clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ | |
189 | } \ | |
190 | static inline int nilfs_##name(struct the_nilfs *nilfs) \ | |
191 | { \ | |
192 | return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ | |
193 | } | |
194 | ||
195 | THE_NILFS_FNS(INIT, init) | |
196 | THE_NILFS_FNS(LOADED, loaded) | |
197 | THE_NILFS_FNS(DISCONTINUED, discontinued) | |
65b4643d | 198 | |
e339ad31 RK |
199 | /* Minimum interval of periodical update of superblocks (in seconds) */ |
200 | #define NILFS_SB_FREQ 10 | |
201 | #define NILFS_ALTSB_FREQ 60 /* spare superblock */ | |
202 | ||
79efdd94 JS |
203 | static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) |
204 | { | |
205 | u64 t = get_seconds(); | |
206 | return t < nilfs->ns_sbwtime[0] || | |
207 | t > nilfs->ns_sbwtime[0] + NILFS_SB_FREQ; | |
208 | } | |
209 | ||
210 | static inline int nilfs_altsb_need_update(struct the_nilfs *nilfs) | |
211 | { | |
212 | u64 t = get_seconds(); | |
213 | struct nilfs_super_block **sbp = nilfs->ns_sbp; | |
214 | return sbp[1] && t > nilfs->ns_sbwtime[1] + NILFS_ALTSB_FREQ; | |
215 | } | |
216 | ||
65b4643d | 217 | void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); |
33c8e57c | 218 | struct the_nilfs *find_or_create_nilfs(struct block_device *); |
65b4643d RK |
219 | void put_nilfs(struct the_nilfs *); |
220 | int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *); | |
221 | int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *); | |
222 | int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); | |
6dd47406 | 223 | struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64); |
65b4643d RK |
224 | int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int); |
225 | int nilfs_near_disk_full(struct the_nilfs *); | |
e339ad31 RK |
226 | void nilfs_fall_back_super_block(struct the_nilfs *); |
227 | void nilfs_swap_super_block(struct the_nilfs *); | |
65b4643d RK |
228 | |
229 | ||
230 | static inline void get_nilfs(struct the_nilfs *nilfs) | |
231 | { | |
232 | /* Caller must have at least one reference of the_nilfs. */ | |
233 | atomic_inc(&nilfs->ns_count); | |
234 | } | |
235 | ||
65b4643d RK |
236 | static inline void |
237 | nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) | |
238 | { | |
027d6404 | 239 | down_write(&nilfs->ns_writer_sem); |
65b4643d | 240 | nilfs->ns_writer = sbi; |
027d6404 | 241 | up_write(&nilfs->ns_writer_sem); |
65b4643d RK |
242 | } |
243 | ||
244 | static inline void | |
245 | nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) | |
246 | { | |
027d6404 | 247 | down_write(&nilfs->ns_writer_sem); |
65b4643d RK |
248 | if (sbi == nilfs->ns_writer) |
249 | nilfs->ns_writer = NULL; | |
027d6404 | 250 | up_write(&nilfs->ns_writer_sem); |
65b4643d RK |
251 | } |
252 | ||
6dd47406 RK |
253 | static inline void nilfs_put_sbinfo(struct nilfs_sb_info *sbi) |
254 | { | |
a9245860 | 255 | if (atomic_dec_and_test(&sbi->s_count)) |
6dd47406 RK |
256 | kfree(sbi); |
257 | } | |
258 | ||
65b4643d RK |
259 | static inline void |
260 | nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, | |
261 | sector_t *seg_start, sector_t *seg_end) | |
262 | { | |
263 | *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; | |
264 | *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; | |
265 | if (segnum == 0) | |
266 | *seg_start = nilfs->ns_first_data_block; | |
267 | } | |
268 | ||
269 | static inline sector_t | |
270 | nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) | |
271 | { | |
272 | return (segnum == 0) ? nilfs->ns_first_data_block : | |
273 | (sector_t)nilfs->ns_blocks_per_segment * segnum; | |
274 | } | |
275 | ||
276 | static inline __u64 | |
277 | nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) | |
278 | { | |
279 | sector_t segnum = blocknr; | |
280 | ||
281 | sector_div(segnum, nilfs->ns_blocks_per_segment); | |
282 | return segnum; | |
283 | } | |
284 | ||
285 | static inline void | |
286 | nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, | |
287 | sector_t seg_end) | |
288 | { | |
289 | /* terminate the current full segment (used in case of I/O-error) */ | |
290 | nilfs->ns_pseg_offset = seg_end - seg_start + 1; | |
291 | } | |
292 | ||
293 | static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) | |
294 | { | |
295 | /* move forward with a full segment */ | |
296 | nilfs->ns_segnum = nilfs->ns_nextnum; | |
297 | nilfs->ns_pseg_offset = 0; | |
298 | nilfs->ns_seg_seq++; | |
299 | } | |
300 | ||
301 | static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) | |
302 | { | |
303 | __u64 cno; | |
304 | ||
305 | spin_lock(&nilfs->ns_last_segment_lock); | |
306 | cno = nilfs->ns_last_cno; | |
307 | spin_unlock(&nilfs->ns_last_segment_lock); | |
308 | return cno; | |
309 | } | |
310 | ||
cece5520 RK |
311 | static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) |
312 | { | |
313 | return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; | |
314 | } | |
315 | ||
65b4643d | 316 | #endif /* _THE_NILFS_H */ |