2 * the_nilfs.h - the_nilfs shared structure.
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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.
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.
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
20 * Written by Ryusuke Konishi <ryusuke@osrg.net>
27 #include <linux/types.h>
28 #include <linux/buffer_head.h>
30 #include <linux/blkdev.h>
31 #include <linux/backing-dev.h>
34 /* the_nilfs struct */
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 */
43 * struct the_nilfs - struct to supervise multiple nilfs mount points
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_writer_mutex: mutex protecting ns_writer attach/detach
52 * @ns_writer_refcount: number of referrers on ns_writer
53 * @ns_current: back pointer to current mount
54 * @ns_sbh: buffer heads of on-disk super blocks
55 * @ns_sbp: pointers to super block data
56 * @ns_sbwtime: previous write time of super blocks
57 * @ns_sbsize: size of valid data in super block
58 * @ns_supers: list of nilfs super block structs
59 * @ns_seg_seq: segment sequence counter
60 * @ns_segnum: index number of the latest full segment.
61 * @ns_nextnum: index number of the full segment index to be used next
62 * @ns_pseg_offset: offset of next partial segment in the current full segment
63 * @ns_cno: next checkpoint number
64 * @ns_ctime: write time of the last segment
65 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
66 * @ns_ndirtyblks: Number of dirty data blocks
67 * @ns_last_segment_lock: lock protecting fields for the latest segment
68 * @ns_last_pseg: start block number of the latest segment
69 * @ns_last_seq: sequence value of the latest segment
70 * @ns_last_cno: checkpoint number of the latest segment
71 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
72 * @ns_free_segments_count: counter of free segments
73 * @ns_segctor_sem: segment constructor semaphore
74 * @ns_dat: DAT file inode
75 * @ns_cpfile: checkpoint file inode
76 * @ns_sufile: segusage file inode
77 * @ns_gc_dat: shadow inode of the DAT file inode for GC
78 * @ns_gc_inodes: dummy inodes to keep live blocks
79 * @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks
80 * @ns_blocksize_bits: bit length of block size
81 * @ns_nsegments: number of segments in filesystem
82 * @ns_blocks_per_segment: number of blocks per segment
83 * @ns_r_segments_percentage: reserved segments percentage
84 * @ns_nrsvsegs: number of reserved segments
85 * @ns_first_data_block: block number of first data block
86 * @ns_inode_size: size of on-disk inode
87 * @ns_first_ino: first not-special inode number
88 * @ns_crc_seed: seed value of CRC32 calculation
91 unsigned long ns_flags
;
93 struct list_head ns_list
;
95 struct block_device
*ns_bdev
;
96 struct backing_dev_info
*ns_bdi
;
97 struct nilfs_sb_info
*ns_writer
;
98 struct rw_semaphore ns_sem
;
99 struct mutex ns_writer_mutex
;
100 atomic_t ns_writer_refcount
;
102 struct nilfs_sb_info
*ns_current
;
106 * - loading the latest checkpoint exclusively.
107 * - allocating a new full segment.
108 * - protecting s_dirt in the super_block struct
109 * (see nilfs_write_super) and the following fields.
111 struct buffer_head
*ns_sbh
[2];
112 struct nilfs_super_block
*ns_sbp
[2];
113 time_t ns_sbwtime
[2];
115 unsigned ns_mount_state
;
116 struct list_head ns_supers
;
119 * Following fields are dedicated to a writable FS-instance.
120 * Except for the period seeking checkpoint, code outside the segment
121 * constructor must lock a segment semaphore while accessing these
123 * The writable FS-instance is sole during a lifetime of the_nilfs.
128 unsigned long ns_pseg_offset
;
131 time_t ns_nongc_ctime
;
132 atomic_t ns_ndirtyblks
;
135 * The following fields hold information on the latest partial segment
136 * written to disk with a super root. These fields are protected by
137 * ns_last_segment_lock.
139 spinlock_t ns_last_segment_lock
;
140 sector_t ns_last_pseg
;
144 unsigned long ns_free_segments_count
;
146 struct rw_semaphore ns_segctor_sem
;
149 * Following fields are lock free except for the period before
150 * the_nilfs is initialized.
152 struct inode
*ns_dat
;
153 struct inode
*ns_cpfile
;
154 struct inode
*ns_sufile
;
155 struct inode
*ns_gc_dat
;
157 /* GC inode list and hash table head */
158 struct list_head ns_gc_inodes
;
159 struct hlist_head
*ns_gc_inodes_h
;
161 /* Disk layout information (static) */
162 unsigned int ns_blocksize_bits
;
163 unsigned long ns_nsegments
;
164 unsigned long ns_blocks_per_segment
;
165 unsigned long ns_r_segments_percentage
;
166 unsigned long ns_nrsvsegs
;
167 unsigned long ns_first_data_block
;
173 #define NILFS_GCINODE_HASH_BITS 8
174 #define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS)
176 #define THE_NILFS_FNS(bit, name) \
177 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
179 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
181 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
183 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
185 static inline int nilfs_##name(struct the_nilfs *nilfs) \
187 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
190 THE_NILFS_FNS(INIT
, init
)
191 THE_NILFS_FNS(LOADED
, loaded
)
192 THE_NILFS_FNS(DISCONTINUED
, discontinued
)
194 /* Minimum interval of periodical update of superblocks (in seconds) */
195 #define NILFS_SB_FREQ 10
196 #define NILFS_ALTSB_FREQ 60 /* spare superblock */
198 void nilfs_set_last_segment(struct the_nilfs
*, sector_t
, u64
, __u64
);
199 struct the_nilfs
*find_or_create_nilfs(struct block_device
*);
200 void put_nilfs(struct the_nilfs
*);
201 int init_nilfs(struct the_nilfs
*, struct nilfs_sb_info
*, char *);
202 int load_nilfs(struct the_nilfs
*, struct nilfs_sb_info
*);
203 int nilfs_count_free_blocks(struct the_nilfs
*, sector_t
*);
204 struct nilfs_sb_info
*nilfs_find_sbinfo(struct the_nilfs
*, int, __u64
);
205 int nilfs_checkpoint_is_mounted(struct the_nilfs
*, __u64
, int);
206 int nilfs_near_disk_full(struct the_nilfs
*);
207 void nilfs_fall_back_super_block(struct the_nilfs
*);
208 void nilfs_swap_super_block(struct the_nilfs
*);
211 static inline void get_nilfs(struct the_nilfs
*nilfs
)
213 /* Caller must have at least one reference of the_nilfs. */
214 atomic_inc(&nilfs
->ns_count
);
217 static inline struct nilfs_sb_info
*nilfs_get_writer(struct the_nilfs
*nilfs
)
219 if (atomic_inc_and_test(&nilfs
->ns_writer_refcount
))
220 mutex_lock(&nilfs
->ns_writer_mutex
);
221 return nilfs
->ns_writer
;
224 static inline void nilfs_put_writer(struct the_nilfs
*nilfs
)
226 if (atomic_add_negative(-1, &nilfs
->ns_writer_refcount
))
227 mutex_unlock(&nilfs
->ns_writer_mutex
);
231 nilfs_attach_writer(struct the_nilfs
*nilfs
, struct nilfs_sb_info
*sbi
)
233 mutex_lock(&nilfs
->ns_writer_mutex
);
234 nilfs
->ns_writer
= sbi
;
235 mutex_unlock(&nilfs
->ns_writer_mutex
);
239 nilfs_detach_writer(struct the_nilfs
*nilfs
, struct nilfs_sb_info
*sbi
)
241 mutex_lock(&nilfs
->ns_writer_mutex
);
242 if (sbi
== nilfs
->ns_writer
)
243 nilfs
->ns_writer
= NULL
;
244 mutex_unlock(&nilfs
->ns_writer_mutex
);
247 static inline void nilfs_put_sbinfo(struct nilfs_sb_info
*sbi
)
249 if (!atomic_dec_and_test(&sbi
->s_count
))
254 nilfs_get_segment_range(struct the_nilfs
*nilfs
, __u64 segnum
,
255 sector_t
*seg_start
, sector_t
*seg_end
)
257 *seg_start
= (sector_t
)nilfs
->ns_blocks_per_segment
* segnum
;
258 *seg_end
= *seg_start
+ nilfs
->ns_blocks_per_segment
- 1;
260 *seg_start
= nilfs
->ns_first_data_block
;
263 static inline sector_t
264 nilfs_get_segment_start_blocknr(struct the_nilfs
*nilfs
, __u64 segnum
)
266 return (segnum
== 0) ? nilfs
->ns_first_data_block
:
267 (sector_t
)nilfs
->ns_blocks_per_segment
* segnum
;
271 nilfs_get_segnum_of_block(struct the_nilfs
*nilfs
, sector_t blocknr
)
273 sector_t segnum
= blocknr
;
275 sector_div(segnum
, nilfs
->ns_blocks_per_segment
);
280 nilfs_terminate_segment(struct the_nilfs
*nilfs
, sector_t seg_start
,
283 /* terminate the current full segment (used in case of I/O-error) */
284 nilfs
->ns_pseg_offset
= seg_end
- seg_start
+ 1;
287 static inline void nilfs_shift_to_next_segment(struct the_nilfs
*nilfs
)
289 /* move forward with a full segment */
290 nilfs
->ns_segnum
= nilfs
->ns_nextnum
;
291 nilfs
->ns_pseg_offset
= 0;
295 static inline __u64
nilfs_last_cno(struct the_nilfs
*nilfs
)
299 spin_lock(&nilfs
->ns_last_segment_lock
);
300 cno
= nilfs
->ns_last_cno
;
301 spin_unlock(&nilfs
->ns_last_segment_lock
);
305 static inline int nilfs_segment_is_active(struct the_nilfs
*nilfs
, __u64 n
)
307 return n
== nilfs
->ns_segnum
|| n
== nilfs
->ns_nextnum
;
310 #endif /* _THE_NILFS_H */