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_DISCONTINUED, /* 'next' pointer chain has broken */
40 THE_NILFS_GC_RUNNING, /* gc process is running */
41 THE_NILFS_SB_DIRTY, /* super block is dirty */
45 * struct the_nilfs - struct to supervise multiple nilfs mount points
47 * @ns_bdev: block device
48 * @ns_sem: semaphore for shared states
49 * @ns_sbh: buffer heads of on-disk super blocks
50 * @ns_sbp: pointers to super block data
51 * @ns_sbwtime: previous write time of super block
52 * @ns_sbwcount: write count of super block
53 * @ns_sbsize: size of valid data in super block
54 * @ns_seg_seq: segment sequence counter
55 * @ns_segnum: index number of the latest full segment.
56 * @ns_nextnum: index number of the full segment index to be used next
57 * @ns_pseg_offset: offset of next partial segment in the current full segment
58 * @ns_cno: next checkpoint number
59 * @ns_ctime: write time of the last segment
60 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
61 * @ns_ndirtyblks: Number of dirty data blocks
62 * @ns_last_segment_lock: lock protecting fields for the latest segment
63 * @ns_last_pseg: start block number of the latest segment
64 * @ns_last_seq: sequence value of the latest segment
65 * @ns_last_cno: checkpoint number of the latest segment
66 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
67 * @ns_prev_seq: base sequence number used to decide if advance log cursor
68 * @ns_segctor_sem: segment constructor semaphore
69 * @ns_dat: DAT file inode
70 * @ns_cpfile: checkpoint file inode
71 * @ns_sufile: segusage file inode
72 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
73 * @ns_cptree_lock: lock protecting @ns_cptree
74 * @ns_gc_inodes: dummy inodes to keep live blocks
75 * @ns_mount_opt: mount options
76 * @ns_blocksize_bits: bit length of block size
77 * @ns_blocksize: block size
78 * @ns_nsegments: number of segments in filesystem
79 * @ns_blocks_per_segment: number of blocks per segment
80 * @ns_r_segments_percentage: reserved segments percentage
81 * @ns_nrsvsegs: number of reserved segments
82 * @ns_first_data_block: block number of first data block
83 * @ns_inode_size: size of on-disk inode
84 * @ns_first_ino: first not-special inode number
85 * @ns_crc_seed: seed value of CRC32 calculation
88 unsigned long ns_flags;
90 struct block_device *ns_bdev;
91 struct rw_semaphore ns_sem;
95 * - loading the latest checkpoint exclusively.
96 * - allocating a new full segment.
97 * - protecting s_dirt in the super_block struct
98 * (see nilfs_write_super) and the following fields.
100 struct buffer_head *ns_sbh[2];
101 struct nilfs_super_block *ns_sbp[2];
103 unsigned ns_sbwcount;
105 unsigned ns_mount_state;
108 * Following fields are dedicated to a writable FS-instance.
109 * Except for the period seeking checkpoint, code outside the segment
110 * constructor must lock a segment semaphore while accessing these
112 * The writable FS-instance is sole during a lifetime of the_nilfs.
117 unsigned long ns_pseg_offset;
120 time_t ns_nongc_ctime;
121 atomic_t ns_ndirtyblks;
124 * The following fields hold information on the latest partial segment
125 * written to disk with a super root. These fields are protected by
126 * ns_last_segment_lock.
128 spinlock_t ns_last_segment_lock;
129 sector_t ns_last_pseg;
135 struct rw_semaphore ns_segctor_sem;
138 * Following fields are lock free except for the period before
139 * the_nilfs is initialized.
141 struct inode *ns_dat;
142 struct inode *ns_cpfile;
143 struct inode *ns_sufile;
145 /* Checkpoint tree */
146 struct rb_root ns_cptree;
147 spinlock_t ns_cptree_lock;
150 struct list_head ns_gc_inodes;
153 unsigned long ns_mount_opt;
155 /* Disk layout information (static) */
156 unsigned int ns_blocksize_bits;
157 unsigned int ns_blocksize;
158 unsigned long ns_nsegments;
159 unsigned long ns_blocks_per_segment;
160 unsigned long ns_r_segments_percentage;
161 unsigned long ns_nrsvsegs;
162 unsigned long ns_first_data_block;
168 #define THE_NILFS_FNS(bit, name) \
169 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
171 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
173 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
175 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
177 static inline int nilfs_##name(struct the_nilfs *nilfs) \
179 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
182 THE_NILFS_FNS(INIT, init)
183 THE_NILFS_FNS(DISCONTINUED, discontinued)
184 THE_NILFS_FNS(GC_RUNNING, gc_running)
185 THE_NILFS_FNS(SB_DIRTY, sb_dirty)
188 * Mount option operations
190 #define nilfs_clear_opt(nilfs, opt) \
191 do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)
192 #define nilfs_set_opt(nilfs, opt) \
193 do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0)
194 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
195 #define nilfs_write_opt(nilfs, mask, opt) \
196 do { (nilfs)->ns_mount_opt = \
197 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \
198 NILFS_MOUNT_##opt); \
202 * struct nilfs_root - nilfs root object
203 * @cno: checkpoint number
204 * @rb_node: red-black tree node
205 * @count: refcount of this structure
206 * @nilfs: nilfs object
209 * @inodes_count: number of inodes
210 * @blocks_count: number of blocks (Reserved)
214 struct rb_node rb_node;
217 struct the_nilfs *nilfs;
220 atomic_t inodes_count;
221 atomic_t blocks_count;
224 /* Special checkpoint number */
225 #define NILFS_CPTREE_CURRENT_CNO 0
227 /* Minimum interval of periodical update of superblocks (in seconds) */
228 #define NILFS_SB_FREQ 10
230 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
232 u64 t = get_seconds();
233 return t < nilfs->ns_sbwtime || t > nilfs->ns_sbwtime + NILFS_SB_FREQ;
236 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
238 int flip_bits = nilfs->ns_sbwcount & 0x0FL;
239 return (flip_bits != 0x08 && flip_bits != 0x0F);
242 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
243 struct the_nilfs *alloc_nilfs(struct block_device *bdev);
244 void destroy_nilfs(struct the_nilfs *nilfs);
245 int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
246 int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
247 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
248 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
249 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
250 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
252 void nilfs_put_root(struct nilfs_root *root);
253 struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64);
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 nilfs_get_root(struct nilfs_root *root)
261 atomic_inc(&root->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 */