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>
29 #include <linux/rbtree.h>
31 #include <linux/blkdev.h>
32 #include <linux/backing-dev.h>
33 #include <linux/slab.h>
36 /* the_nilfs struct */
38 THE_NILFS_INIT
= 0, /* Information from super_block is set */
39 THE_NILFS_LOADED
, /* Roll-back/roll-forward has done and
40 the latest checkpoint was loaded */
41 THE_NILFS_DISCONTINUED
, /* 'next' pointer chain has broken */
42 THE_NILFS_GC_RUNNING
, /* gc process is running */
43 THE_NILFS_SB_DIRTY
, /* super block is dirty */
47 * struct the_nilfs - struct to supervise multiple nilfs mount points
49 * @ns_bdev: block device
50 * @ns_bdi: backing dev info
51 * @ns_writer: back pointer to writable nilfs_sb_info
52 * @ns_sem: semaphore for shared states
53 * @ns_writer_sem: semaphore protecting ns_writer attach/detach
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 block
57 * @ns_sbwcount: write count of super block
58 * @ns_sbsize: size of valid data in super block
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_prev_seq: base sequence number used to decide if advance log cursor
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_cptree: rb-tree of all mounted checkpoints (nilfs_root)
78 * @ns_cptree_lock: lock protecting @ns_cptree
79 * @ns_gc_inodes: dummy inodes to keep live blocks
80 * @ns_blocksize_bits: bit length of block size
81 * @ns_blocksize: 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
92 unsigned long ns_flags
;
94 struct block_device
*ns_bdev
;
95 struct backing_dev_info
*ns_bdi
;
96 struct nilfs_sb_info
*ns_writer
;
97 struct rw_semaphore ns_sem
;
98 struct rw_semaphore ns_writer_sem
;
102 * - loading the latest checkpoint exclusively.
103 * - allocating a new full segment.
104 * - protecting s_dirt in the super_block struct
105 * (see nilfs_write_super) and the following fields.
107 struct buffer_head
*ns_sbh
[2];
108 struct nilfs_super_block
*ns_sbp
[2];
110 unsigned ns_sbwcount
;
112 unsigned ns_mount_state
;
115 * Following fields are dedicated to a writable FS-instance.
116 * Except for the period seeking checkpoint, code outside the segment
117 * constructor must lock a segment semaphore while accessing these
119 * The writable FS-instance is sole during a lifetime of the_nilfs.
124 unsigned long ns_pseg_offset
;
127 time_t ns_nongc_ctime
;
128 atomic_t ns_ndirtyblks
;
131 * The following fields hold information on the latest partial segment
132 * written to disk with a super root. These fields are protected by
133 * ns_last_segment_lock.
135 spinlock_t ns_last_segment_lock
;
136 sector_t ns_last_pseg
;
142 struct rw_semaphore ns_segctor_sem
;
145 * Following fields are lock free except for the period before
146 * the_nilfs is initialized.
148 struct inode
*ns_dat
;
149 struct inode
*ns_cpfile
;
150 struct inode
*ns_sufile
;
152 /* Checkpoint tree */
153 struct rb_root ns_cptree
;
154 spinlock_t ns_cptree_lock
;
157 struct list_head ns_gc_inodes
;
159 /* Disk layout information (static) */
160 unsigned int ns_blocksize_bits
;
161 unsigned int ns_blocksize
;
162 unsigned long ns_nsegments
;
163 unsigned long ns_blocks_per_segment
;
164 unsigned long ns_r_segments_percentage
;
165 unsigned long ns_nrsvsegs
;
166 unsigned long ns_first_data_block
;
172 #define THE_NILFS_FNS(bit, name) \
173 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
175 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
177 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
179 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
181 static inline int nilfs_##name(struct the_nilfs *nilfs) \
183 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
186 THE_NILFS_FNS(INIT
, init
)
187 THE_NILFS_FNS(LOADED
, loaded
)
188 THE_NILFS_FNS(DISCONTINUED
, discontinued
)
189 THE_NILFS_FNS(GC_RUNNING
, gc_running
)
190 THE_NILFS_FNS(SB_DIRTY
, sb_dirty
)
193 * struct nilfs_root - nilfs root object
194 * @cno: checkpoint number
195 * @rb_node: red-black tree node
196 * @count: refcount of this structure
197 * @nilfs: nilfs object
200 * @inodes_count: number of inodes
201 * @blocks_count: number of blocks (Reserved)
205 struct rb_node rb_node
;
208 struct the_nilfs
*nilfs
;
211 atomic_t inodes_count
;
212 atomic_t blocks_count
;
215 /* Special checkpoint number */
216 #define NILFS_CPTREE_CURRENT_CNO 0
218 /* Minimum interval of periodical update of superblocks (in seconds) */
219 #define NILFS_SB_FREQ 10
221 static inline int nilfs_sb_need_update(struct the_nilfs
*nilfs
)
223 u64 t
= get_seconds();
224 return t
< nilfs
->ns_sbwtime
|| t
> nilfs
->ns_sbwtime
+ NILFS_SB_FREQ
;
227 static inline int nilfs_sb_will_flip(struct the_nilfs
*nilfs
)
229 int flip_bits
= nilfs
->ns_sbwcount
& 0x0FL
;
230 return (flip_bits
!= 0x08 && flip_bits
!= 0x0F);
233 void nilfs_set_last_segment(struct the_nilfs
*, sector_t
, u64
, __u64
);
234 struct the_nilfs
*alloc_nilfs(struct block_device
*bdev
);
235 void destroy_nilfs(struct the_nilfs
*nilfs
);
236 int init_nilfs(struct the_nilfs
*, struct nilfs_sb_info
*, char *);
237 int load_nilfs(struct the_nilfs
*, struct nilfs_sb_info
*);
238 int nilfs_discard_segments(struct the_nilfs
*, __u64
*, size_t);
239 int nilfs_count_free_blocks(struct the_nilfs
*, sector_t
*);
240 struct nilfs_root
*nilfs_lookup_root(struct the_nilfs
*nilfs
, __u64 cno
);
241 struct nilfs_root
*nilfs_find_or_create_root(struct the_nilfs
*nilfs
,
243 void nilfs_put_root(struct nilfs_root
*root
);
244 struct nilfs_sb_info
*nilfs_find_sbinfo(struct the_nilfs
*, int, __u64
);
245 int nilfs_near_disk_full(struct the_nilfs
*);
246 void nilfs_fall_back_super_block(struct the_nilfs
*);
247 void nilfs_swap_super_block(struct the_nilfs
*);
250 static inline void nilfs_get_root(struct nilfs_root
*root
)
252 atomic_inc(&root
->count
);
256 nilfs_attach_writer(struct the_nilfs
*nilfs
, struct nilfs_sb_info
*sbi
)
258 down_write(&nilfs
->ns_writer_sem
);
259 nilfs
->ns_writer
= sbi
;
260 up_write(&nilfs
->ns_writer_sem
);
264 nilfs_detach_writer(struct the_nilfs
*nilfs
, struct nilfs_sb_info
*sbi
)
266 down_write(&nilfs
->ns_writer_sem
);
267 if (sbi
== nilfs
->ns_writer
)
268 nilfs
->ns_writer
= NULL
;
269 up_write(&nilfs
->ns_writer_sem
);
272 static inline int nilfs_valid_fs(struct the_nilfs
*nilfs
)
276 down_read(&nilfs
->ns_sem
);
277 valid_fs
= (nilfs
->ns_mount_state
& NILFS_VALID_FS
);
278 up_read(&nilfs
->ns_sem
);
283 nilfs_get_segment_range(struct the_nilfs
*nilfs
, __u64 segnum
,
284 sector_t
*seg_start
, sector_t
*seg_end
)
286 *seg_start
= (sector_t
)nilfs
->ns_blocks_per_segment
* segnum
;
287 *seg_end
= *seg_start
+ nilfs
->ns_blocks_per_segment
- 1;
289 *seg_start
= nilfs
->ns_first_data_block
;
292 static inline sector_t
293 nilfs_get_segment_start_blocknr(struct the_nilfs
*nilfs
, __u64 segnum
)
295 return (segnum
== 0) ? nilfs
->ns_first_data_block
:
296 (sector_t
)nilfs
->ns_blocks_per_segment
* segnum
;
300 nilfs_get_segnum_of_block(struct the_nilfs
*nilfs
, sector_t blocknr
)
302 sector_t segnum
= blocknr
;
304 sector_div(segnum
, nilfs
->ns_blocks_per_segment
);
309 nilfs_terminate_segment(struct the_nilfs
*nilfs
, sector_t seg_start
,
312 /* terminate the current full segment (used in case of I/O-error) */
313 nilfs
->ns_pseg_offset
= seg_end
- seg_start
+ 1;
316 static inline void nilfs_shift_to_next_segment(struct the_nilfs
*nilfs
)
318 /* move forward with a full segment */
319 nilfs
->ns_segnum
= nilfs
->ns_nextnum
;
320 nilfs
->ns_pseg_offset
= 0;
324 static inline __u64
nilfs_last_cno(struct the_nilfs
*nilfs
)
328 spin_lock(&nilfs
->ns_last_segment_lock
);
329 cno
= nilfs
->ns_last_cno
;
330 spin_unlock(&nilfs
->ns_last_segment_lock
);
334 static inline int nilfs_segment_is_active(struct the_nilfs
*nilfs
, __u64 n
)
336 return n
== nilfs
->ns_segnum
|| n
== nilfs
->ns_nextnum
;
339 #endif /* _THE_NILFS_H */