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Ryusuke Konishi65b46432009-04-06 19:01:23 -07001/*
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 */
35enum {
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 */
Jiro SEKIBA1cf58fa2009-09-03 22:24:17 +090040 THE_NILFS_GC_RUNNING, /* gc process is running */
Ryusuke Konishi65b46432009-04-06 19:01:23 -070041};
42
43/**
44 * struct the_nilfs - struct to supervise multiple nilfs mount points
45 * @ns_flags: flags
46 * @ns_count: reference count
Ryusuke Konishi33c8e572009-06-08 01:39:29 +090047 * @ns_list: list head for nilfs_list
Ryusuke Konishi65b46432009-04-06 19:01:23 -070048 * @ns_bdev: block device
49 * @ns_bdi: backing dev info
50 * @ns_writer: back pointer to writable nilfs_sb_info
51 * @ns_sem: semaphore for shared states
Ryusuke Konishie59399d2009-06-08 01:39:32 +090052 * @ns_super_sem: semaphore for global operations across super block instances
Ryusuke Konishiaa7dfb82009-06-08 01:39:33 +090053 * @ns_mount_mutex: mutex protecting mount process of nilfs
Ryusuke Konishi027d6402009-08-02 22:45:33 +090054 * @ns_writer_sem: semaphore protecting ns_writer attach/detach
Ryusuke Konishi3f82ff52009-06-08 01:39:30 +090055 * @ns_current: back pointer to current mount
Ryusuke Konishie339ad32009-04-06 19:01:59 -070056 * @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
Ryusuke Konishi65b46432009-04-06 19:01:23 -070060 * @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
Ryusuke Konishi2c2e52f2009-04-06 19:01:54 -070073 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
Ryusuke Konishi65b46432009-04-06 19:01:23 -070074 * @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
Ryusuke Konishi65b46432009-04-06 19:01:23 -070082 * @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 */
92struct the_nilfs {
93 unsigned long ns_flags;
94 atomic_t ns_count;
Ryusuke Konishi33c8e572009-06-08 01:39:29 +090095 struct list_head ns_list;
Ryusuke Konishi65b46432009-04-06 19:01:23 -070096
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;
Ryusuke Konishie59399d2009-06-08 01:39:32 +0900101 struct rw_semaphore ns_super_sem;
Ryusuke Konishiaa7dfb82009-06-08 01:39:33 +0900102 struct mutex ns_mount_mutex;
Ryusuke Konishi027d6402009-08-02 22:45:33 +0900103 struct rw_semaphore ns_writer_sem;
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700104
Ryusuke Konishie59399d2009-06-08 01:39:32 +0900105 /*
106 * components protected by ns_super_sem
107 */
Ryusuke Konishi3f82ff52009-06-08 01:39:30 +0900108 struct nilfs_sb_info *ns_current;
Ryusuke Konishie59399d2009-06-08 01:39:32 +0900109 struct list_head ns_supers;
Ryusuke Konishi3f82ff52009-06-08 01:39:30 +0900110
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700111 /*
112 * used for
113 * - loading the latest checkpoint exclusively.
114 * - allocating a new full segment.
115 * - protecting s_dirt in the super_block struct
116 * (see nilfs_write_super) and the following fields.
117 */
Ryusuke Konishie339ad32009-04-06 19:01:59 -0700118 struct buffer_head *ns_sbh[2];
119 struct nilfs_super_block *ns_sbp[2];
120 time_t ns_sbwtime[2];
121 unsigned ns_sbsize;
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700122 unsigned ns_mount_state;
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700123
124 /*
125 * Following fields are dedicated to a writable FS-instance.
126 * Except for the period seeking checkpoint, code outside the segment
Ryusuke Konishi47420c72009-04-06 19:01:45 -0700127 * constructor must lock a segment semaphore while accessing these
128 * fields.
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700129 * The writable FS-instance is sole during a lifetime of the_nilfs.
130 */
131 u64 ns_seg_seq;
132 __u64 ns_segnum;
133 __u64 ns_nextnum;
134 unsigned long ns_pseg_offset;
135 __u64 ns_cno;
136 time_t ns_ctime;
137 time_t ns_nongc_ctime;
138 atomic_t ns_ndirtyblks;
139
140 /*
141 * The following fields hold information on the latest partial segment
142 * written to disk with a super root. These fields are protected by
143 * ns_last_segment_lock.
144 */
145 spinlock_t ns_last_segment_lock;
146 sector_t ns_last_pseg;
147 u64 ns_last_seq;
148 __u64 ns_last_cno;
Ryusuke Konishi2c2e52f2009-04-06 19:01:54 -0700149 u64 ns_prot_seq;
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700150 unsigned long ns_free_segments_count;
151
152 struct rw_semaphore ns_segctor_sem;
153
154 /*
155 * Following fields are lock free except for the period before
156 * the_nilfs is initialized.
157 */
158 struct inode *ns_dat;
159 struct inode *ns_cpfile;
160 struct inode *ns_sufile;
161 struct inode *ns_gc_dat;
162
163 /* GC inode list and hash table head */
164 struct list_head ns_gc_inodes;
165 struct hlist_head *ns_gc_inodes_h;
166
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700167 /* Disk layout information (static) */
168 unsigned int ns_blocksize_bits;
169 unsigned long ns_nsegments;
170 unsigned long ns_blocks_per_segment;
171 unsigned long ns_r_segments_percentage;
172 unsigned long ns_nrsvsegs;
173 unsigned long ns_first_data_block;
174 int ns_inode_size;
175 int ns_first_ino;
176 u32 ns_crc_seed;
177};
178
179#define NILFS_GCINODE_HASH_BITS 8
180#define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS)
181
182#define THE_NILFS_FNS(bit, name) \
183static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
184{ \
185 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
186} \
187static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
188{ \
189 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
190} \
191static inline int nilfs_##name(struct the_nilfs *nilfs) \
192{ \
193 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
194}
195
196THE_NILFS_FNS(INIT, init)
197THE_NILFS_FNS(LOADED, loaded)
198THE_NILFS_FNS(DISCONTINUED, discontinued)
Jiro SEKIBA1cf58fa2009-09-03 22:24:17 +0900199THE_NILFS_FNS(GC_RUNNING, gc_running)
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700200
Ryusuke Konishie339ad32009-04-06 19:01:59 -0700201/* Minimum interval of periodical update of superblocks (in seconds) */
202#define NILFS_SB_FREQ 10
203#define NILFS_ALTSB_FREQ 60 /* spare superblock */
204
Jiro SEKIBA79efdd92009-07-23 01:26:34 +0900205static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
206{
207 u64 t = get_seconds();
208 return t < nilfs->ns_sbwtime[0] ||
209 t > nilfs->ns_sbwtime[0] + NILFS_SB_FREQ;
210}
211
212static inline int nilfs_altsb_need_update(struct the_nilfs *nilfs)
213{
214 u64 t = get_seconds();
215 struct nilfs_super_block **sbp = nilfs->ns_sbp;
216 return sbp[1] && t > nilfs->ns_sbwtime[1] + NILFS_ALTSB_FREQ;
217}
218
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700219void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
Ryusuke Konishi33c8e572009-06-08 01:39:29 +0900220struct the_nilfs *find_or_create_nilfs(struct block_device *);
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700221void put_nilfs(struct the_nilfs *);
222int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
223int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
224int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
Ryusuke Konishi6dd47402009-06-08 01:39:31 +0900225struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64);
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700226int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int);
227int nilfs_near_disk_full(struct the_nilfs *);
Ryusuke Konishie339ad32009-04-06 19:01:59 -0700228void nilfs_fall_back_super_block(struct the_nilfs *);
229void nilfs_swap_super_block(struct the_nilfs *);
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700230
231
232static inline void get_nilfs(struct the_nilfs *nilfs)
233{
234 /* Caller must have at least one reference of the_nilfs. */
235 atomic_inc(&nilfs->ns_count);
236}
237
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700238static inline void
239nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
240{
Ryusuke Konishi027d6402009-08-02 22:45:33 +0900241 down_write(&nilfs->ns_writer_sem);
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700242 nilfs->ns_writer = sbi;
Ryusuke Konishi027d6402009-08-02 22:45:33 +0900243 up_write(&nilfs->ns_writer_sem);
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700244}
245
246static inline void
247nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
248{
Ryusuke Konishi027d6402009-08-02 22:45:33 +0900249 down_write(&nilfs->ns_writer_sem);
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700250 if (sbi == nilfs->ns_writer)
251 nilfs->ns_writer = NULL;
Ryusuke Konishi027d6402009-08-02 22:45:33 +0900252 up_write(&nilfs->ns_writer_sem);
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700253}
254
Ryusuke Konishi6dd47402009-06-08 01:39:31 +0900255static inline void nilfs_put_sbinfo(struct nilfs_sb_info *sbi)
256{
Ryusuke Konishia9245862009-08-19 00:29:43 +0900257 if (atomic_dec_and_test(&sbi->s_count))
Ryusuke Konishi6dd47402009-06-08 01:39:31 +0900258 kfree(sbi);
259}
260
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700261static inline void
262nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
263 sector_t *seg_start, sector_t *seg_end)
264{
265 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
266 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
267 if (segnum == 0)
268 *seg_start = nilfs->ns_first_data_block;
269}
270
271static inline sector_t
272nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
273{
274 return (segnum == 0) ? nilfs->ns_first_data_block :
275 (sector_t)nilfs->ns_blocks_per_segment * segnum;
276}
277
278static inline __u64
279nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
280{
281 sector_t segnum = blocknr;
282
283 sector_div(segnum, nilfs->ns_blocks_per_segment);
284 return segnum;
285}
286
287static inline void
288nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
289 sector_t seg_end)
290{
291 /* terminate the current full segment (used in case of I/O-error) */
292 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
293}
294
295static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
296{
297 /* move forward with a full segment */
298 nilfs->ns_segnum = nilfs->ns_nextnum;
299 nilfs->ns_pseg_offset = 0;
300 nilfs->ns_seg_seq++;
301}
302
303static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
304{
305 __u64 cno;
306
307 spin_lock(&nilfs->ns_last_segment_lock);
308 cno = nilfs->ns_last_cno;
309 spin_unlock(&nilfs->ns_last_segment_lock);
310 return cno;
311}
312
Ryusuke Konishicece5522009-04-06 19:01:58 -0700313static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
314{
315 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
316}
317
Ryusuke Konishi65b46432009-04-06 19:01:23 -0700318#endif /* _THE_NILFS_H */