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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 | }; |
41 | |
42 | /** |
43 | * struct the_nilfs - struct to supervise multiple nilfs mount points |
44 | * @ns_flags: flags |
45 | * @ns_count: reference count |
46 | * @ns_list: list head for nilfs_list |
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_super_sem: semaphore for global operations across super block instances |
52 | * @ns_mount_mutex: mutex protecting mount process of nilfs |
53 | * @ns_writer_mutex: mutex protecting ns_writer attach/detach |
54 | * @ns_writer_refcount: number of referrers on ns_writer |
55 | * @ns_current: back pointer to current mount |
56 | * @ns_sbh: buffer heads of on-disk super blocks |
57 | * @ns_sbp: pointers to super block data |
58 | * @ns_sbwtime: previous write time of super blocks |
59 | * @ns_sbsize: size of valid data in super block |
60 | * @ns_supers: list of nilfs super block structs |
61 | * @ns_seg_seq: segment sequence counter |
62 | * @ns_segnum: index number of the latest full segment. |
63 | * @ns_nextnum: index number of the full segment index to be used next |
64 | * @ns_pseg_offset: offset of next partial segment in the current full segment |
65 | * @ns_cno: next checkpoint number |
66 | * @ns_ctime: write time of the last segment |
67 | * @ns_nongc_ctime: write time of the last segment not for cleaner operation |
68 | * @ns_ndirtyblks: Number of dirty data blocks |
69 | * @ns_last_segment_lock: lock protecting fields for the latest segment |
70 | * @ns_last_pseg: start block number of the latest segment |
71 | * @ns_last_seq: sequence value of the latest segment |
72 | * @ns_last_cno: checkpoint number of the latest segment |
73 | * @ns_prot_seq: least sequence number of segments which must not be reclaimed |
74 | * @ns_free_segments_count: counter of free segments |
75 | * @ns_segctor_sem: segment constructor semaphore |
76 | * @ns_dat: DAT file inode |
77 | * @ns_cpfile: checkpoint file inode |
78 | * @ns_sufile: segusage file inode |
79 | * @ns_gc_dat: shadow inode of the DAT file inode for GC |
80 | * @ns_gc_inodes: dummy inodes to keep live blocks |
81 | * @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks |
82 | * @ns_blocksize_bits: bit length of block size |
83 | * @ns_nsegments: number of segments in filesystem |
84 | * @ns_blocks_per_segment: number of blocks per segment |
85 | * @ns_r_segments_percentage: reserved segments percentage |
86 | * @ns_nrsvsegs: number of reserved segments |
87 | * @ns_first_data_block: block number of first data block |
88 | * @ns_inode_size: size of on-disk inode |
89 | * @ns_first_ino: first not-special inode number |
90 | * @ns_crc_seed: seed value of CRC32 calculation |
91 | */ |
92 | struct the_nilfs { |
93 | unsigned long ns_flags; |
94 | atomic_t ns_count; |
95 | struct list_head ns_list; |
96 | |
97 | struct block_device *ns_bdev; |
98 | struct backing_dev_info *ns_bdi; |
99 | struct nilfs_sb_info *ns_writer; |
100 | struct rw_semaphore ns_sem; |
101 | struct rw_semaphore ns_super_sem; |
102 | struct mutex ns_mount_mutex; |
103 | struct mutex ns_writer_mutex; |
104 | atomic_t ns_writer_refcount; |
105 | |
106 | /* |
107 | * components protected by ns_super_sem |
108 | */ |
109 | struct nilfs_sb_info *ns_current; |
110 | struct list_head ns_supers; |
111 | |
112 | /* |
113 | * used for |
114 | * - loading the latest checkpoint exclusively. |
115 | * - allocating a new full segment. |
116 | * - protecting s_dirt in the super_block struct |
117 | * (see nilfs_write_super) and the following fields. |
118 | */ |
119 | struct buffer_head *ns_sbh[2]; |
120 | struct nilfs_super_block *ns_sbp[2]; |
121 | time_t ns_sbwtime[2]; |
122 | unsigned ns_sbsize; |
123 | unsigned ns_mount_state; |
124 | |
125 | /* |
126 | * Following fields are dedicated to a writable FS-instance. |
127 | * Except for the period seeking checkpoint, code outside the segment |
128 | * constructor must lock a segment semaphore while accessing these |
129 | * fields. |
130 | * The writable FS-instance is sole during a lifetime of the_nilfs. |
131 | */ |
132 | u64 ns_seg_seq; |
133 | __u64 ns_segnum; |
134 | __u64 ns_nextnum; |
135 | unsigned long ns_pseg_offset; |
136 | __u64 ns_cno; |
137 | time_t ns_ctime; |
138 | time_t ns_nongc_ctime; |
139 | atomic_t ns_ndirtyblks; |
140 | |
141 | /* |
142 | * The following fields hold information on the latest partial segment |
143 | * written to disk with a super root. These fields are protected by |
144 | * ns_last_segment_lock. |
145 | */ |
146 | spinlock_t ns_last_segment_lock; |
147 | sector_t ns_last_pseg; |
148 | u64 ns_last_seq; |
149 | __u64 ns_last_cno; |
150 | u64 ns_prot_seq; |
151 | unsigned long ns_free_segments_count; |
152 | |
153 | struct rw_semaphore ns_segctor_sem; |
154 | |
155 | /* |
156 | * Following fields are lock free except for the period before |
157 | * the_nilfs is initialized. |
158 | */ |
159 | struct inode *ns_dat; |
160 | struct inode *ns_cpfile; |
161 | struct inode *ns_sufile; |
162 | struct inode *ns_gc_dat; |
163 | |
164 | /* GC inode list and hash table head */ |
165 | struct list_head ns_gc_inodes; |
166 | struct hlist_head *ns_gc_inodes_h; |
167 | |
168 | /* Disk layout information (static) */ |
169 | unsigned int ns_blocksize_bits; |
170 | unsigned long ns_nsegments; |
171 | unsigned long ns_blocks_per_segment; |
172 | unsigned long ns_r_segments_percentage; |
173 | unsigned long ns_nrsvsegs; |
174 | unsigned long ns_first_data_block; |
175 | int ns_inode_size; |
176 | int ns_first_ino; |
177 | u32 ns_crc_seed; |
178 | }; |
179 | |
180 | #define NILFS_GCINODE_HASH_BITS 8 |
181 | #define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS) |
182 | |
183 | #define THE_NILFS_FNS(bit, name) \ |
184 | static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ |
185 | { \ |
186 | set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ |
187 | } \ |
188 | static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ |
189 | { \ |
190 | clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ |
191 | } \ |
192 | static inline int nilfs_##name(struct the_nilfs *nilfs) \ |
193 | { \ |
194 | return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ |
195 | } |
196 | |
197 | THE_NILFS_FNS(INIT, init) |
198 | THE_NILFS_FNS(LOADED, loaded) |
199 | THE_NILFS_FNS(DISCONTINUED, discontinued) |
200 | |
201 | /* Minimum interval of periodical update of superblocks (in seconds) */ |
202 | #define NILFS_SB_FREQ 10 |
203 | #define NILFS_ALTSB_FREQ 60 /* spare superblock */ |
204 | |
205 | void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); |
206 | struct the_nilfs *find_or_create_nilfs(struct block_device *); |
207 | void put_nilfs(struct the_nilfs *); |
208 | int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *); |
209 | int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *); |
210 | int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); |
211 | struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64); |
212 | int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int); |
213 | int nilfs_near_disk_full(struct the_nilfs *); |
214 | void nilfs_fall_back_super_block(struct the_nilfs *); |
215 | void nilfs_swap_super_block(struct the_nilfs *); |
216 | |
217 | |
218 | static inline void get_nilfs(struct the_nilfs *nilfs) |
219 | { |
220 | /* Caller must have at least one reference of the_nilfs. */ |
221 | atomic_inc(&nilfs->ns_count); |
222 | } |
223 | |
224 | static inline struct nilfs_sb_info *nilfs_get_writer(struct the_nilfs *nilfs) |
225 | { |
226 | if (atomic_inc_and_test(&nilfs->ns_writer_refcount)) |
227 | mutex_lock(&nilfs->ns_writer_mutex); |
228 | return nilfs->ns_writer; |
229 | } |
230 | |
231 | static inline void nilfs_put_writer(struct the_nilfs *nilfs) |
232 | { |
233 | if (atomic_add_negative(-1, &nilfs->ns_writer_refcount)) |
234 | mutex_unlock(&nilfs->ns_writer_mutex); |
235 | } |
236 | |
237 | static inline void |
238 | nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) |
239 | { |
240 | mutex_lock(&nilfs->ns_writer_mutex); |
241 | nilfs->ns_writer = sbi; |
242 | mutex_unlock(&nilfs->ns_writer_mutex); |
243 | } |
244 | |
245 | static inline void |
246 | nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) |
247 | { |
248 | mutex_lock(&nilfs->ns_writer_mutex); |
249 | if (sbi == nilfs->ns_writer) |
250 | nilfs->ns_writer = NULL; |
251 | mutex_unlock(&nilfs->ns_writer_mutex); |
252 | } |
253 | |
254 | static inline void nilfs_put_sbinfo(struct nilfs_sb_info *sbi) |
255 | { |
256 | if (atomic_dec_and_test(&sbi->s_count)) |
257 | kfree(sbi); |
258 | } |
259 | |
260 | static inline void |
261 | nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, |
262 | sector_t *seg_start, sector_t *seg_end) |
263 | { |
264 | *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; |
265 | *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; |
266 | if (segnum == 0) |
267 | *seg_start = nilfs->ns_first_data_block; |
268 | } |
269 | |
270 | static inline sector_t |
271 | nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) |
272 | { |
273 | return (segnum == 0) ? nilfs->ns_first_data_block : |
274 | (sector_t)nilfs->ns_blocks_per_segment * segnum; |
275 | } |
276 | |
277 | static inline __u64 |
278 | nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) |
279 | { |
280 | sector_t segnum = blocknr; |
281 | |
282 | sector_div(segnum, nilfs->ns_blocks_per_segment); |
283 | return segnum; |
284 | } |
285 | |
286 | static inline void |
287 | nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, |
288 | sector_t seg_end) |
289 | { |
290 | /* terminate the current full segment (used in case of I/O-error) */ |
291 | nilfs->ns_pseg_offset = seg_end - seg_start + 1; |
292 | } |
293 | |
294 | static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) |
295 | { |
296 | /* move forward with a full segment */ |
297 | nilfs->ns_segnum = nilfs->ns_nextnum; |
298 | nilfs->ns_pseg_offset = 0; |
299 | nilfs->ns_seg_seq++; |
300 | } |
301 | |
302 | static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) |
303 | { |
304 | __u64 cno; |
305 | |
306 | spin_lock(&nilfs->ns_last_segment_lock); |
307 | cno = nilfs->ns_last_cno; |
308 | spin_unlock(&nilfs->ns_last_segment_lock); |
309 | return cno; |
310 | } |
311 | |
312 | static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) |
313 | { |
314 | return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; |
315 | } |
316 | |
317 | #endif /* _THE_NILFS_H */ |
318 |
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