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>
32 #include <linux/slab.h>
35 /* the_nilfs struct */
37 THE_NILFS_INIT
= 0, /* Information from super_block is set */
38 THE_NILFS_LOADED
, /* Roll-back/roll-forward has done and
39 the latest checkpoint was loaded */
40 THE_NILFS_DISCONTINUED
, /* 'next' pointer chain has broken */
41 THE_NILFS_GC_RUNNING
, /* gc process is running */
42 THE_NILFS_SB_DIRTY
, /* super block is dirty */
46 * struct the_nilfs - struct to supervise multiple nilfs mount points
48 * @ns_count: reference count
49 * @ns_list: list head for nilfs_list
50 * @ns_bdev: block device
51 * @ns_bdi: backing dev info
52 * @ns_writer: back pointer to writable nilfs_sb_info
53 * @ns_sem: semaphore for shared states
54 * @ns_super_sem: semaphore for global operations across super block instances
55 * @ns_mount_mutex: mutex protecting mount process of nilfs
56 * @ns_writer_sem: semaphore protecting ns_writer attach/detach
57 * @ns_current: back pointer to current mount
58 * @ns_sbh: buffer heads of on-disk super blocks
59 * @ns_sbp: pointers to super block data
60 * @ns_sbwtime: previous write time of super block
61 * @ns_sbwcount: write count of super block
62 * @ns_sbsize: size of valid data in super block
63 * @ns_supers: list of nilfs super block structs
64 * @ns_seg_seq: segment sequence counter
65 * @ns_segnum: index number of the latest full segment.
66 * @ns_nextnum: index number of the full segment index to be used next
67 * @ns_pseg_offset: offset of next partial segment in the current full segment
68 * @ns_cno: next checkpoint number
69 * @ns_ctime: write time of the last segment
70 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
71 * @ns_ndirtyblks: Number of dirty data blocks
72 * @ns_last_segment_lock: lock protecting fields for the latest segment
73 * @ns_last_pseg: start block number of the latest segment
74 * @ns_last_seq: sequence value of the latest segment
75 * @ns_last_cno: checkpoint number of the latest segment
76 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
77 * @ns_segctor_sem: segment constructor semaphore
78 * @ns_dat: DAT file inode
79 * @ns_cpfile: checkpoint file inode
80 * @ns_sufile: segusage file inode
81 * @ns_gc_dat: shadow inode of the DAT file inode for GC
82 * @ns_gc_inodes: dummy inodes to keep live blocks
83 * @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks
84 * @ns_blocksize_bits: bit length of block size
85 * @ns_blocksize: block size
86 * @ns_nsegments: number of segments in filesystem
87 * @ns_blocks_per_segment: number of blocks per segment
88 * @ns_r_segments_percentage: reserved segments percentage
89 * @ns_nrsvsegs: number of reserved segments
90 * @ns_first_data_block: block number of first data block
91 * @ns_inode_size: size of on-disk inode
92 * @ns_first_ino: first not-special inode number
93 * @ns_crc_seed: seed value of CRC32 calculation
96 unsigned long ns_flags
;
98 struct list_head ns_list
;
100 struct block_device
*ns_bdev
;
101 struct backing_dev_info
*ns_bdi
;
102 struct nilfs_sb_info
*ns_writer
;
103 struct rw_semaphore ns_sem
;
104 struct rw_semaphore ns_super_sem
;
105 struct mutex ns_mount_mutex
;
106 struct rw_semaphore ns_writer_sem
;
109 * components protected by ns_super_sem
111 struct nilfs_sb_info
*ns_current
;
112 struct list_head ns_supers
;
116 * - loading the latest checkpoint exclusively.
117 * - allocating a new full segment.
118 * - protecting s_dirt in the super_block struct
119 * (see nilfs_write_super) and the following fields.
121 struct buffer_head
*ns_sbh
[2];
122 struct nilfs_super_block
*ns_sbp
[2];
124 unsigned ns_sbwcount
;
126 unsigned ns_mount_state
;
129 * Following fields are dedicated to a writable FS-instance.
130 * Except for the period seeking checkpoint, code outside the segment
131 * constructor must lock a segment semaphore while accessing these
133 * The writable FS-instance is sole during a lifetime of the_nilfs.
138 unsigned long ns_pseg_offset
;
141 time_t ns_nongc_ctime
;
142 atomic_t ns_ndirtyblks
;
145 * The following fields hold information on the latest partial segment
146 * written to disk with a super root. These fields are protected by
147 * ns_last_segment_lock.
149 spinlock_t ns_last_segment_lock
;
150 sector_t ns_last_pseg
;
155 struct rw_semaphore ns_segctor_sem
;
158 * Following fields are lock free except for the period before
159 * the_nilfs is initialized.
161 struct inode
*ns_dat
;
162 struct inode
*ns_cpfile
;
163 struct inode
*ns_sufile
;
164 struct inode
*ns_gc_dat
;
166 /* GC inode list and hash table head */
167 struct list_head ns_gc_inodes
;
168 struct hlist_head
*ns_gc_inodes_h
;
170 /* Disk layout information (static) */
171 unsigned int ns_blocksize_bits
;
172 unsigned int ns_blocksize
;
173 unsigned long ns_nsegments
;
174 unsigned long ns_blocks_per_segment
;
175 unsigned long ns_r_segments_percentage
;
176 unsigned long ns_nrsvsegs
;
177 unsigned long ns_first_data_block
;
183 #define NILFS_GCINODE_HASH_BITS 8
184 #define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS)
186 #define THE_NILFS_FNS(bit, name) \
187 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
189 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
191 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
193 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
195 static inline int nilfs_##name(struct the_nilfs *nilfs) \
197 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
200 THE_NILFS_FNS(INIT
, init
)
201 THE_NILFS_FNS(LOADED
, loaded
)
202 THE_NILFS_FNS(DISCONTINUED
, discontinued
)
203 THE_NILFS_FNS(GC_RUNNING
, gc_running
)
204 THE_NILFS_FNS(SB_DIRTY
, sb_dirty
)
206 /* Minimum interval of periodical update of superblocks (in seconds) */
207 #define NILFS_SB_FREQ 10
209 static inline int nilfs_sb_need_update(struct the_nilfs
*nilfs
)
211 u64 t
= get_seconds();
212 return t
< nilfs
->ns_sbwtime
|| t
> nilfs
->ns_sbwtime
+ NILFS_SB_FREQ
;
215 static inline int nilfs_sb_will_flip(struct the_nilfs
*nilfs
)
217 int flip_bits
= nilfs
->ns_sbwcount
& 0x0FL
;
218 return (flip_bits
!= 0x08 && flip_bits
!= 0x0F);
221 void nilfs_set_last_segment(struct the_nilfs
*, sector_t
, u64
, __u64
);
222 struct the_nilfs
*find_or_create_nilfs(struct block_device
*);
223 void put_nilfs(struct the_nilfs
*);
224 int init_nilfs(struct the_nilfs
*, struct nilfs_sb_info
*, char *);
225 int load_nilfs(struct the_nilfs
*, struct nilfs_sb_info
*);
226 int nilfs_discard_segments(struct the_nilfs
*, __u64
*, size_t);
227 int nilfs_count_free_blocks(struct the_nilfs
*, sector_t
*);
228 struct nilfs_sb_info
*nilfs_find_sbinfo(struct the_nilfs
*, int, __u64
);
229 int nilfs_checkpoint_is_mounted(struct the_nilfs
*, __u64
, int);
230 int nilfs_near_disk_full(struct the_nilfs
*);
231 void nilfs_fall_back_super_block(struct the_nilfs
*);
232 void nilfs_swap_super_block(struct the_nilfs
*);
235 static inline void get_nilfs(struct the_nilfs
*nilfs
)
237 /* Caller must have at least one reference of the_nilfs. */
238 atomic_inc(&nilfs
->ns_count
);
242 nilfs_attach_writer(struct the_nilfs
*nilfs
, struct nilfs_sb_info
*sbi
)
244 down_write(&nilfs
->ns_writer_sem
);
245 nilfs
->ns_writer
= sbi
;
246 up_write(&nilfs
->ns_writer_sem
);
250 nilfs_detach_writer(struct the_nilfs
*nilfs
, struct nilfs_sb_info
*sbi
)
252 down_write(&nilfs
->ns_writer_sem
);
253 if (sbi
== nilfs
->ns_writer
)
254 nilfs
->ns_writer
= NULL
;
255 up_write(&nilfs
->ns_writer_sem
);
258 static inline void nilfs_put_sbinfo(struct nilfs_sb_info
*sbi
)
260 if (atomic_dec_and_test(&sbi
->s_count
))
264 static inline int nilfs_valid_fs(struct the_nilfs
*nilfs
)
268 down_read(&nilfs
->ns_sem
);
269 valid_fs
= (nilfs
->ns_mount_state
& NILFS_VALID_FS
);
270 up_read(&nilfs
->ns_sem
);
275 nilfs_get_segment_range(struct the_nilfs
*nilfs
, __u64 segnum
,
276 sector_t
*seg_start
, sector_t
*seg_end
)
278 *seg_start
= (sector_t
)nilfs
->ns_blocks_per_segment
* segnum
;
279 *seg_end
= *seg_start
+ nilfs
->ns_blocks_per_segment
- 1;
281 *seg_start
= nilfs
->ns_first_data_block
;
284 static inline sector_t
285 nilfs_get_segment_start_blocknr(struct the_nilfs
*nilfs
, __u64 segnum
)
287 return (segnum
== 0) ? nilfs
->ns_first_data_block
:
288 (sector_t
)nilfs
->ns_blocks_per_segment
* segnum
;
292 nilfs_get_segnum_of_block(struct the_nilfs
*nilfs
, sector_t blocknr
)
294 sector_t segnum
= blocknr
;
296 sector_div(segnum
, nilfs
->ns_blocks_per_segment
);
301 nilfs_terminate_segment(struct the_nilfs
*nilfs
, sector_t seg_start
,
304 /* terminate the current full segment (used in case of I/O-error) */
305 nilfs
->ns_pseg_offset
= seg_end
- seg_start
+ 1;
308 static inline void nilfs_shift_to_next_segment(struct the_nilfs
*nilfs
)
310 /* move forward with a full segment */
311 nilfs
->ns_segnum
= nilfs
->ns_nextnum
;
312 nilfs
->ns_pseg_offset
= 0;
316 static inline __u64
nilfs_last_cno(struct the_nilfs
*nilfs
)
320 spin_lock(&nilfs
->ns_last_segment_lock
);
321 cno
= nilfs
->ns_last_cno
;
322 spin_unlock(&nilfs
->ns_last_segment_lock
);
326 static inline int nilfs_segment_is_active(struct the_nilfs
*nilfs
, __u64 n
)
328 return n
== nilfs
->ns_segnum
|| n
== nilfs
->ns_nextnum
;
331 #endif /* _THE_NILFS_H */