1 /*
2 * the_nilfs.h - the_nilfs shared structure.
3 *
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5 *
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.
10 *
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.
15 *
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
19 *
20 * Written by Ryusuke Konishi <ryusuke@osrg.net>
21 *
22 */
23
24 #ifndef _THE_NILFS_H
25 #define _THE_NILFS_H
26
27 #include <linux/types.h>
28 #include <linux/buffer_head.h>
29 #include <linux/rbtree.h>
30 #include <linux/fs.h>
31 #include <linux/blkdev.h>
32 #include <linux/backing-dev.h>
33 #include <linux/slab.h>
34
35 struct nilfs_sc_info;
36
37 /* the_nilfs struct */
38 enum {
39 THE_NILFS_INIT = 0, /* Information from super_block is set */
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 */
43 };
44
45 /**
46 * struct the_nilfs - struct to supervise multiple nilfs mount points
47 * @ns_flags: flags
48 * @ns_bdev: block device
49 * @ns_sem: semaphore for shared states
50 * @ns_sbh: buffer heads of on-disk super blocks
51 * @ns_sbp: pointers to super block data
52 * @ns_sbwtime: previous write time of super block
53 * @ns_sbwcount: write count of super block
54 * @ns_sbsize: size of valid data in super block
55 * @ns_seg_seq: segment sequence counter
56 * @ns_segnum: index number of the latest full segment.
57 * @ns_nextnum: index number of the full segment index to be used next
58 * @ns_pseg_offset: offset of next partial segment in the current full segment
59 * @ns_cno: next checkpoint number
60 * @ns_ctime: write time of the last segment
61 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
62 * @ns_ndirtyblks: Number of dirty data blocks
63 * @ns_last_segment_lock: lock protecting fields for the latest segment
64 * @ns_last_pseg: start block number of the latest segment
65 * @ns_last_seq: sequence value of the latest segment
66 * @ns_last_cno: checkpoint number of the latest segment
67 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
68 * @ns_prev_seq: base sequence number used to decide if advance log cursor
69 * @ns_writer: log writer
70 * @ns_segctor_sem: semaphore protecting log write
71 * @ns_dat: DAT file inode
72 * @ns_cpfile: checkpoint file inode
73 * @ns_sufile: segusage file inode
74 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
75 * @ns_cptree_lock: lock protecting @ns_cptree
76 * @ns_dirty_files: list of dirty files
77 * @ns_inode_lock: lock protecting @ns_dirty_files
78 * @ns_gc_inodes: dummy inodes to keep live blocks
79 * @ns_next_generation: next generation number for inodes
80 * @ns_next_gen_lock: lock protecting @ns_next_generation
81 * @ns_mount_opt: mount options
82 * @ns_resuid: uid for reserved blocks
83 * @ns_resgid: gid for reserved blocks
84 * @ns_interval: checkpoint creation interval
85 * @ns_watermark: watermark for the number of dirty buffers
86 * @ns_blocksize_bits: bit length of block size
87 * @ns_blocksize: block size
88 * @ns_nsegments: number of segments in filesystem
89 * @ns_blocks_per_segment: number of blocks per segment
90 * @ns_r_segments_percentage: reserved segments percentage
91 * @ns_nrsvsegs: number of reserved segments
92 * @ns_first_data_block: block number of first data block
93 * @ns_inode_size: size of on-disk inode
94 * @ns_first_ino: first not-special inode number
95 * @ns_crc_seed: seed value of CRC32 calculation
96 */
97 struct the_nilfs {
98 unsigned long ns_flags;
99
100 struct block_device *ns_bdev;
101 struct rw_semaphore ns_sem;
102
103 /*
104 * used for
105 * - loading the latest checkpoint exclusively.
106 * - allocating a new full segment.
107 * - protecting s_dirt in the super_block struct
108 * (see nilfs_write_super) and the following fields.
109 */
110 struct buffer_head *ns_sbh[2];
111 struct nilfs_super_block *ns_sbp[2];
112 time_t ns_sbwtime;
113 unsigned ns_sbwcount;
114 unsigned ns_sbsize;
115 unsigned ns_mount_state;
116
117 /*
118 * Following fields are dedicated to a writable FS-instance.
119 * Except for the period seeking checkpoint, code outside the segment
120 * constructor must lock a segment semaphore while accessing these
121 * fields.
122 * The writable FS-instance is sole during a lifetime of the_nilfs.
123 */
124 u64 ns_seg_seq;
125 __u64 ns_segnum;
126 __u64 ns_nextnum;
127 unsigned long ns_pseg_offset;
128 __u64 ns_cno;
129 time_t ns_ctime;
130 time_t ns_nongc_ctime;
131 atomic_t ns_ndirtyblks;
132
133 /*
134 * The following fields hold information on the latest partial segment
135 * written to disk with a super root. These fields are protected by
136 * ns_last_segment_lock.
137 */
138 spinlock_t ns_last_segment_lock;
139 sector_t ns_last_pseg;
140 u64 ns_last_seq;
141 __u64 ns_last_cno;
142 u64 ns_prot_seq;
143 u64 ns_prev_seq;
144
145 struct nilfs_sc_info *ns_writer;
146 struct rw_semaphore ns_segctor_sem;
147
148 /*
149 * Following fields are lock free except for the period before
150 * the_nilfs is initialized.
151 */
152 struct inode *ns_dat;
153 struct inode *ns_cpfile;
154 struct inode *ns_sufile;
155
156 /* Checkpoint tree */
157 struct rb_root ns_cptree;
158 spinlock_t ns_cptree_lock;
159
160 /* Dirty inode list */
161 struct list_head ns_dirty_files;
162 spinlock_t ns_inode_lock;
163
164 /* GC inode list */
165 struct list_head ns_gc_inodes;
166
167 /* Inode allocator */
168 u32 ns_next_generation;
169 spinlock_t ns_next_gen_lock;
170
171 /* Mount options */
172 unsigned long ns_mount_opt;
173
174 uid_t ns_resuid;
175 gid_t ns_resgid;
176 unsigned long ns_interval;
177 unsigned long ns_watermark;
178
179 /* Disk layout information (static) */
180 unsigned int ns_blocksize_bits;
181 unsigned int ns_blocksize;
182 unsigned long ns_nsegments;
183 unsigned long ns_blocks_per_segment;
184 unsigned long ns_r_segments_percentage;
185 unsigned long ns_nrsvsegs;
186 unsigned long ns_first_data_block;
187 int ns_inode_size;
188 int ns_first_ino;
189 u32 ns_crc_seed;
190 };
191
192 #define THE_NILFS_FNS(bit, name) \
193 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
194 { \
195 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
196 } \
197 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
198 { \
199 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
200 } \
201 static inline int nilfs_##name(struct the_nilfs *nilfs) \
202 { \
203 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
204 }
205
206 THE_NILFS_FNS(INIT, init)
207 THE_NILFS_FNS(DISCONTINUED, discontinued)
208 THE_NILFS_FNS(GC_RUNNING, gc_running)
209 THE_NILFS_FNS(SB_DIRTY, sb_dirty)
210
211 /*
212 * Mount option operations
213 */
214 #define nilfs_clear_opt(nilfs, opt) \
215 do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)
216 #define nilfs_set_opt(nilfs, opt) \
217 do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0)
218 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
219 #define nilfs_write_opt(nilfs, mask, opt) \
220 do { (nilfs)->ns_mount_opt = \
221 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \
222 NILFS_MOUNT_##opt); \
223 } while (0)
224
225 /**
226 * struct nilfs_root - nilfs root object
227 * @cno: checkpoint number
228 * @rb_node: red-black tree node
229 * @count: refcount of this structure
230 * @nilfs: nilfs object
231 * @ifile: inode file
232 * @root: root inode
233 * @inodes_count: number of inodes
234 * @blocks_count: number of blocks (Reserved)
235 */
236 struct nilfs_root {
237 __u64 cno;
238 struct rb_node rb_node;
239
240 atomic_t count;
241 struct the_nilfs *nilfs;
242 struct inode *ifile;
243
244 atomic_t inodes_count;
245 atomic_t blocks_count;
246 };
247
248 /* Special checkpoint number */
249 #define NILFS_CPTREE_CURRENT_CNO 0
250
251 /* Minimum interval of periodical update of superblocks (in seconds) */
252 #define NILFS_SB_FREQ 10
253
nilfs_sb_need_update(struct the_nilfs * nilfs)254 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
255 {
256 u64 t = get_seconds();
257 return t < nilfs->ns_sbwtime || t > nilfs->ns_sbwtime + NILFS_SB_FREQ;
258 }
259
nilfs_sb_will_flip(struct the_nilfs * nilfs)260 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
261 {
262 int flip_bits = nilfs->ns_sbwcount & 0x0FL;
263 return (flip_bits != 0x08 && flip_bits != 0x0F);
264 }
265
266 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
267 struct the_nilfs *alloc_nilfs(struct block_device *bdev);
268 void destroy_nilfs(struct the_nilfs *nilfs);
269 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data);
270 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
271 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
272 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
273 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
274 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
275 __u64 cno);
276 void nilfs_put_root(struct nilfs_root *root);
277 int nilfs_near_disk_full(struct the_nilfs *);
278 void nilfs_fall_back_super_block(struct the_nilfs *);
279 void nilfs_swap_super_block(struct the_nilfs *);
280
281
nilfs_get_root(struct nilfs_root * root)282 static inline void nilfs_get_root(struct nilfs_root *root)
283 {
284 atomic_inc(&root->count);
285 }
286
nilfs_valid_fs(struct the_nilfs * nilfs)287 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
288 {
289 unsigned valid_fs;
290
291 down_read(&nilfs->ns_sem);
292 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
293 up_read(&nilfs->ns_sem);
294 return valid_fs;
295 }
296
297 static inline void
nilfs_get_segment_range(struct the_nilfs * nilfs,__u64 segnum,sector_t * seg_start,sector_t * seg_end)298 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
299 sector_t *seg_start, sector_t *seg_end)
300 {
301 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
302 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
303 if (segnum == 0)
304 *seg_start = nilfs->ns_first_data_block;
305 }
306
307 static inline sector_t
nilfs_get_segment_start_blocknr(struct the_nilfs * nilfs,__u64 segnum)308 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
309 {
310 return (segnum == 0) ? nilfs->ns_first_data_block :
311 (sector_t)nilfs->ns_blocks_per_segment * segnum;
312 }
313
314 static inline __u64
nilfs_get_segnum_of_block(struct the_nilfs * nilfs,sector_t blocknr)315 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
316 {
317 sector_t segnum = blocknr;
318
319 sector_div(segnum, nilfs->ns_blocks_per_segment);
320 return segnum;
321 }
322
323 static inline void
nilfs_terminate_segment(struct the_nilfs * nilfs,sector_t seg_start,sector_t seg_end)324 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
325 sector_t seg_end)
326 {
327 /* terminate the current full segment (used in case of I/O-error) */
328 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
329 }
330
nilfs_shift_to_next_segment(struct the_nilfs * nilfs)331 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
332 {
333 /* move forward with a full segment */
334 nilfs->ns_segnum = nilfs->ns_nextnum;
335 nilfs->ns_pseg_offset = 0;
336 nilfs->ns_seg_seq++;
337 }
338
nilfs_last_cno(struct the_nilfs * nilfs)339 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
340 {
341 __u64 cno;
342
343 spin_lock(&nilfs->ns_last_segment_lock);
344 cno = nilfs->ns_last_cno;
345 spin_unlock(&nilfs->ns_last_segment_lock);
346 return cno;
347 }
348
nilfs_segment_is_active(struct the_nilfs * nilfs,__u64 n)349 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
350 {
351 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
352 }
353
354 #endif /* _THE_NILFS_H */
355