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_count: reference count
50 * @ns_list: list head for nilfs_list
51 * @ns_bdev: block device
52 * @ns_bdi: backing dev info
53 * @ns_writer: back pointer to writable nilfs_sb_info
54 * @ns_sem: semaphore for shared states
55 * @ns_mount_mutex: mutex protecting mount process of nilfs
56 * @ns_writer_sem: semaphore protecting ns_writer attach/detach
57 * @ns_sbh: buffer heads of on-disk super blocks
58 * @ns_sbp: pointers to super block data
59 * @ns_sbwtime: previous write time of super block
60 * @ns_sbwcount: write count of super block
61 * @ns_sbsize: size of valid data in super block
62 * @ns_seg_seq: segment sequence counter
63 * @ns_segnum: index number of the latest full segment.
64 * @ns_nextnum: index number of the full segment index to be used next
65 * @ns_pseg_offset: offset of next partial segment in the current full segment
66 * @ns_cno: next checkpoint number
67 * @ns_ctime: write time of the last segment
68 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
69 * @ns_ndirtyblks: Number of dirty data blocks
70 * @ns_last_segment_lock: lock protecting fields for the latest segment
71 * @ns_last_pseg: start block number of the latest segment
72 * @ns_last_seq: sequence value of the latest segment
73 * @ns_last_cno: checkpoint number of the latest segment
74 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
75 * @ns_prev_seq: base sequence number used to decide if advance log cursor
76 * @ns_segctor_sem: segment constructor semaphore
77 * @ns_dat: DAT file inode
78 * @ns_cpfile: checkpoint file inode
79 * @ns_sufile: segusage file inode
80 * @ns_gc_dat: shadow inode of the DAT file inode for GC
81 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
82 * @ns_cptree_lock: lock protecting @ns_cptree
83 * @ns_gc_inodes: dummy inodes to keep 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 mutex ns_mount_mutex;
105 struct rw_semaphore ns_writer_sem;
109 * - loading the latest checkpoint exclusively.
110 * - allocating a new full segment.
111 * - protecting s_dirt in the super_block struct
112 * (see nilfs_write_super) and the following fields.
114 struct buffer_head *ns_sbh[2];
115 struct nilfs_super_block *ns_sbp[2];
117 unsigned ns_sbwcount;
119 unsigned ns_mount_state;
122 * Following fields are dedicated to a writable FS-instance.
123 * Except for the period seeking checkpoint, code outside the segment
124 * constructor must lock a segment semaphore while accessing these
126 * The writable FS-instance is sole during a lifetime of the_nilfs.
131 unsigned long ns_pseg_offset;
134 time_t ns_nongc_ctime;
135 atomic_t ns_ndirtyblks;
138 * The following fields hold information on the latest partial segment
139 * written to disk with a super root. These fields are protected by
140 * ns_last_segment_lock.
142 spinlock_t ns_last_segment_lock;
143 sector_t ns_last_pseg;
149 struct rw_semaphore ns_segctor_sem;
152 * Following fields are lock free except for the period before
153 * the_nilfs is initialized.
155 struct inode *ns_dat;
156 struct inode *ns_cpfile;
157 struct inode *ns_sufile;
158 struct inode *ns_gc_dat;
160 /* Checkpoint tree */
161 struct rb_root ns_cptree;
162 spinlock_t ns_cptree_lock;
165 struct list_head ns_gc_inodes;
167 /* Disk layout information (static) */
168 unsigned int ns_blocksize_bits;
169 unsigned int ns_blocksize;
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;
180 #define THE_NILFS_FNS(bit, name) \
181 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
183 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
185 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
187 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
189 static inline int nilfs_##name(struct the_nilfs *nilfs) \
191 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
194 THE_NILFS_FNS(INIT, init)
195 THE_NILFS_FNS(LOADED, loaded)
196 THE_NILFS_FNS(DISCONTINUED, discontinued)
197 THE_NILFS_FNS(GC_RUNNING, gc_running)
198 THE_NILFS_FNS(SB_DIRTY, sb_dirty)
201 * struct nilfs_root - nilfs root object
202 * @cno: checkpoint number
203 * @rb_node: red-black tree node
204 * @count: refcount of this structure
205 * @nilfs: nilfs object
208 * @inodes_count: number of inodes
209 * @blocks_count: number of blocks (Reserved)
213 struct rb_node rb_node;
216 struct the_nilfs *nilfs;
219 atomic_t inodes_count;
220 atomic_t blocks_count;
223 /* Special checkpoint number */
224 #define NILFS_CPTREE_CURRENT_CNO 0
226 /* Minimum interval of periodical update of superblocks (in seconds) */
227 #define NILFS_SB_FREQ 10
229 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
231 u64 t = get_seconds();
232 return t < nilfs->ns_sbwtime || t > nilfs->ns_sbwtime + NILFS_SB_FREQ;
235 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
237 int flip_bits = nilfs->ns_sbwcount & 0x0FL;
238 return (flip_bits != 0x08 && flip_bits != 0x0F);
241 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
242 struct the_nilfs *find_or_create_nilfs(struct block_device *);
243 void put_nilfs(struct the_nilfs *);
244 int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
245 int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
246 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
247 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
248 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
249 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
251 void nilfs_put_root(struct nilfs_root *root);
252 struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64);
253 int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int);
254 int nilfs_near_disk_full(struct the_nilfs *);
255 void nilfs_fall_back_super_block(struct the_nilfs *);
256 void nilfs_swap_super_block(struct the_nilfs *);
259 static inline void get_nilfs(struct the_nilfs *nilfs)
261 /* Caller must have at least one reference of the_nilfs. */
262 atomic_inc(&nilfs->ns_count);
265 static inline void nilfs_get_root(struct nilfs_root *root)
267 atomic_inc(&root->count);
271 nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
273 down_write(&nilfs->ns_writer_sem);
274 nilfs->ns_writer = sbi;
275 up_write(&nilfs->ns_writer_sem);
279 nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
281 down_write(&nilfs->ns_writer_sem);
282 if (sbi == nilfs->ns_writer)
283 nilfs->ns_writer = NULL;
284 up_write(&nilfs->ns_writer_sem);
287 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
291 down_read(&nilfs->ns_sem);
292 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
293 up_read(&nilfs->ns_sem);
298 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
299 sector_t *seg_start, sector_t *seg_end)
301 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
302 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
304 *seg_start = nilfs->ns_first_data_block;
307 static inline sector_t
308 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
310 return (segnum == 0) ? nilfs->ns_first_data_block :
311 (sector_t)nilfs->ns_blocks_per_segment * segnum;
315 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
317 sector_t segnum = blocknr;
319 sector_div(segnum, nilfs->ns_blocks_per_segment);
324 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
327 /* terminate the current full segment (used in case of I/O-error) */
328 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
331 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
333 /* move forward with a full segment */
334 nilfs->ns_segnum = nilfs->ns_nextnum;
335 nilfs->ns_pseg_offset = 0;
339 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
343 spin_lock(&nilfs->ns_last_segment_lock);
344 cno = nilfs->ns_last_cno;
345 spin_unlock(&nilfs->ns_last_segment_lock);
349 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
351 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
354 #endif /* _THE_NILFS_H */