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_snapshot_mount_mutex: mutex to protect snapshot mounts
51 * @ns_sbh: buffer heads of on-disk super blocks
52 * @ns_sbp: pointers to super block data
53 * @ns_sbwtime: previous write time of super block
54 * @ns_sbwcount: write count of super block
55 * @ns_sbsize: size of valid data in super block
56 * @ns_seg_seq: segment sequence counter
57 * @ns_segnum: index number of the latest full segment.
58 * @ns_nextnum: index number of the full segment index to be used next
59 * @ns_pseg_offset: offset of next partial segment in the current full segment
60 * @ns_cno: next checkpoint number
61 * @ns_ctime: write time of the last segment
62 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
63 * @ns_ndirtyblks: Number of dirty data blocks
64 * @ns_last_segment_lock: lock protecting fields for the latest segment
65 * @ns_last_pseg: start block number of the latest segment
66 * @ns_last_seq: sequence value of the latest segment
67 * @ns_last_cno: checkpoint number of the latest segment
68 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
69 * @ns_prev_seq: base sequence number used to decide if advance log cursor
70 * @ns_writer: log writer
71 * @ns_segctor_sem: semaphore protecting log write
72 * @ns_dat: DAT file inode
73 * @ns_cpfile: checkpoint file inode
74 * @ns_sufile: segusage file inode
75 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
76 * @ns_cptree_lock: lock protecting @ns_cptree
77 * @ns_dirty_files: list of dirty files
78 * @ns_inode_lock: lock protecting @ns_dirty_files
79 * @ns_gc_inodes: dummy inodes to keep live blocks
80 * @ns_next_generation: next generation number for inodes
81 * @ns_next_gen_lock: lock protecting @ns_next_generation
82 * @ns_mount_opt: mount options
83 * @ns_resuid: uid for reserved blocks
84 * @ns_resgid: gid for reserved blocks
85 * @ns_interval: checkpoint creation interval
86 * @ns_watermark: watermark for the number of dirty buffers
87 * @ns_blocksize_bits: bit length of block size
88 * @ns_blocksize: block size
89 * @ns_nsegments: number of segments in filesystem
90 * @ns_blocks_per_segment: number of blocks per segment
91 * @ns_r_segments_percentage: reserved segments percentage
92 * @ns_nrsvsegs: number of reserved segments
93 * @ns_first_data_block: block number of first data block
94 * @ns_inode_size: size of on-disk inode
95 * @ns_first_ino: first not-special inode number
96 * @ns_crc_seed: seed value of CRC32 calculation
97 */
98 struct the_nilfs {
99 unsigned long ns_flags;
100
101 struct block_device *ns_bdev;
102 struct rw_semaphore ns_sem;
103 struct mutex ns_snapshot_mount_mutex;
104
105 /*
106 * used for
107 * - loading the latest checkpoint exclusively.
108 * - allocating a new full segment.
109 * - protecting s_dirt in the super_block struct
110 * (see nilfs_write_super) and the following fields.
111 */
112 struct buffer_head *ns_sbh[2];
113 struct nilfs_super_block *ns_sbp[2];
114 time_t ns_sbwtime;
115 unsigned ns_sbwcount;
116 unsigned ns_sbsize;
117 unsigned ns_mount_state;
118
119 /*
120 * Following fields are dedicated to a writable FS-instance.
121 * Except for the period seeking checkpoint, code outside the segment
122 * constructor must lock a segment semaphore while accessing these
123 * fields.
124 * The writable FS-instance is sole during a lifetime of the_nilfs.
125 */
126 u64 ns_seg_seq;
127 __u64 ns_segnum;
128 __u64 ns_nextnum;
129 unsigned long ns_pseg_offset;
130 __u64 ns_cno;
131 time_t ns_ctime;
132 time_t ns_nongc_ctime;
133 atomic_t ns_ndirtyblks;
134
135 /*
136 * The following fields hold information on the latest partial segment
137 * written to disk with a super root. These fields are protected by
138 * ns_last_segment_lock.
139 */
140 spinlock_t ns_last_segment_lock;
141 sector_t ns_last_pseg;
142 u64 ns_last_seq;
143 __u64 ns_last_cno;
144 u64 ns_prot_seq;
145 u64 ns_prev_seq;
146
147 struct nilfs_sc_info *ns_writer;
148 struct rw_semaphore ns_segctor_sem;
149
150 /*
151 * Following fields are lock free except for the period before
152 * the_nilfs is initialized.
153 */
154 struct inode *ns_dat;
155 struct inode *ns_cpfile;
156 struct inode *ns_sufile;
157
158 /* Checkpoint tree */
159 struct rb_root ns_cptree;
160 spinlock_t ns_cptree_lock;
161
162 /* Dirty inode list */
163 struct list_head ns_dirty_files;
164 spinlock_t ns_inode_lock;
165
166 /* GC inode list */
167 struct list_head ns_gc_inodes;
168
169 /* Inode allocator */
170 u32 ns_next_generation;
171 spinlock_t ns_next_gen_lock;
172
173 /* Mount options */
174 unsigned long ns_mount_opt;
175
176 uid_t ns_resuid;
177 gid_t ns_resgid;
178 unsigned long ns_interval;
179 unsigned long ns_watermark;
180
181 /* Disk layout information (static) */
182 unsigned int ns_blocksize_bits;
183 unsigned int ns_blocksize;
184 unsigned long ns_nsegments;
185 unsigned long ns_blocks_per_segment;
186 unsigned long ns_r_segments_percentage;
187 unsigned long ns_nrsvsegs;
188 unsigned long ns_first_data_block;
189 int ns_inode_size;
190 int ns_first_ino;
191 u32 ns_crc_seed;
192 };
193
194 #define THE_NILFS_FNS(bit, name) \
195 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
196 { \
197 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
198 } \
199 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
200 { \
201 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
202 } \
203 static inline int nilfs_##name(struct the_nilfs *nilfs) \
204 { \
205 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
206 }
207
208 THE_NILFS_FNS(INIT, init)
209 THE_NILFS_FNS(DISCONTINUED, discontinued)
210 THE_NILFS_FNS(GC_RUNNING, gc_running)
211 THE_NILFS_FNS(SB_DIRTY, sb_dirty)
212
213 /*
214 * Mount option operations
215 */
216 #define nilfs_clear_opt(nilfs, opt) \
217 do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)
218 #define nilfs_set_opt(nilfs, opt) \
219 do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0)
220 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
221 #define nilfs_write_opt(nilfs, mask, opt) \
222 do { (nilfs)->ns_mount_opt = \
223 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \
224 NILFS_MOUNT_##opt); \
225 } while (0)
226
227 /**
228 * struct nilfs_root - nilfs root object
229 * @cno: checkpoint number
230 * @rb_node: red-black tree node
231 * @count: refcount of this structure
232 * @nilfs: nilfs object
233 * @ifile: inode file
234 * @root: root inode
235 * @inodes_count: number of inodes
236 * @blocks_count: number of blocks (Reserved)
237 */
238 struct nilfs_root {
239 __u64 cno;
240 struct rb_node rb_node;
241
242 atomic_t count;
243 struct the_nilfs *nilfs;
244 struct inode *ifile;
245
246 atomic_t inodes_count;
247 atomic_t blocks_count;
248 };
249
250 /* Special checkpoint number */
251 #define NILFS_CPTREE_CURRENT_CNO 0
252
253 /* Minimum interval of periodical update of superblocks (in seconds) */
254 #define NILFS_SB_FREQ 10
255
nilfs_sb_need_update(struct the_nilfs * nilfs)256 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
257 {
258 u64 t = get_seconds();
259 return t < nilfs->ns_sbwtime || t > nilfs->ns_sbwtime + NILFS_SB_FREQ;
260 }
261
nilfs_sb_will_flip(struct the_nilfs * nilfs)262 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
263 {
264 int flip_bits = nilfs->ns_sbwcount & 0x0FL;
265 return (flip_bits != 0x08 && flip_bits != 0x0F);
266 }
267
268 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
269 struct the_nilfs *alloc_nilfs(struct block_device *bdev);
270 void destroy_nilfs(struct the_nilfs *nilfs);
271 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data);
272 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
273 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs);
274 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs);
275 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
276 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
277 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
278 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
279 __u64 cno);
280 void nilfs_put_root(struct nilfs_root *root);
281 int nilfs_near_disk_full(struct the_nilfs *);
282 void nilfs_fall_back_super_block(struct the_nilfs *);
283 void nilfs_swap_super_block(struct the_nilfs *);
284
285
nilfs_get_root(struct nilfs_root * root)286 static inline void nilfs_get_root(struct nilfs_root *root)
287 {
288 atomic_inc(&root->count);
289 }
290
nilfs_valid_fs(struct the_nilfs * nilfs)291 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
292 {
293 unsigned valid_fs;
294
295 down_read(&nilfs->ns_sem);
296 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
297 up_read(&nilfs->ns_sem);
298 return valid_fs;
299 }
300
301 static inline void
nilfs_get_segment_range(struct the_nilfs * nilfs,__u64 segnum,sector_t * seg_start,sector_t * seg_end)302 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
303 sector_t *seg_start, sector_t *seg_end)
304 {
305 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
306 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
307 if (segnum == 0)
308 *seg_start = nilfs->ns_first_data_block;
309 }
310
311 static inline sector_t
nilfs_get_segment_start_blocknr(struct the_nilfs * nilfs,__u64 segnum)312 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
313 {
314 return (segnum == 0) ? nilfs->ns_first_data_block :
315 (sector_t)nilfs->ns_blocks_per_segment * segnum;
316 }
317
318 static inline __u64
nilfs_get_segnum_of_block(struct the_nilfs * nilfs,sector_t blocknr)319 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
320 {
321 sector_t segnum = blocknr;
322
323 sector_div(segnum, nilfs->ns_blocks_per_segment);
324 return segnum;
325 }
326
327 static inline void
nilfs_terminate_segment(struct the_nilfs * nilfs,sector_t seg_start,sector_t seg_end)328 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
329 sector_t seg_end)
330 {
331 /* terminate the current full segment (used in case of I/O-error) */
332 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
333 }
334
nilfs_shift_to_next_segment(struct the_nilfs * nilfs)335 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
336 {
337 /* move forward with a full segment */
338 nilfs->ns_segnum = nilfs->ns_nextnum;
339 nilfs->ns_pseg_offset = 0;
340 nilfs->ns_seg_seq++;
341 }
342
nilfs_last_cno(struct the_nilfs * nilfs)343 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
344 {
345 __u64 cno;
346
347 spin_lock(&nilfs->ns_last_segment_lock);
348 cno = nilfs->ns_last_cno;
349 spin_unlock(&nilfs->ns_last_segment_lock);
350 return cno;
351 }
352
nilfs_segment_is_active(struct the_nilfs * nilfs,__u64 n)353 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
354 {
355 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
356 }
357
358 #endif /* _THE_NILFS_H */
359