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 * Written by Ryusuke Konishi.
17 *
18 */
19
20 #ifndef _THE_NILFS_H
21 #define _THE_NILFS_H
22
23 #include <linux/types.h>
24 #include <linux/buffer_head.h>
25 #include <linux/rbtree.h>
26 #include <linux/fs.h>
27 #include <linux/blkdev.h>
28 #include <linux/backing-dev.h>
29 #include <linux/slab.h>
30
31 struct nilfs_sc_info;
32 struct nilfs_sysfs_dev_subgroups;
33
34 /* the_nilfs struct */
35 enum {
36 THE_NILFS_INIT = 0, /* Information from super_block is set */
37 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
38 THE_NILFS_GC_RUNNING, /* gc process is running */
39 THE_NILFS_SB_DIRTY, /* super block is dirty */
40 };
41
42 /**
43 * struct the_nilfs - struct to supervise multiple nilfs mount points
44 * @ns_flags: flags
45 * @ns_flushed_device: flag indicating if all volatile data was flushed
46 * @ns_sb: back pointer to super block instance
47 * @ns_bdev: block device
48 * @ns_sem: semaphore for shared states
49 * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts
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_mount_state: file system state
56 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds)
57 * @ns_seg_seq: segment sequence counter
58 * @ns_segnum: index number of the latest full segment.
59 * @ns_nextnum: index number of the full segment index to be used next
60 * @ns_pseg_offset: offset of next partial segment in the current full segment
61 * @ns_cno: next checkpoint number
62 * @ns_ctime: write time of the last segment
63 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
64 * @ns_ndirtyblks: Number of dirty data blocks
65 * @ns_last_segment_lock: lock protecting fields for the latest segment
66 * @ns_last_pseg: start block number of the latest segment
67 * @ns_last_seq: sequence value of the latest segment
68 * @ns_last_cno: checkpoint number of the latest segment
69 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
70 * @ns_prev_seq: base sequence number used to decide if advance log cursor
71 * @ns_writer: log writer
72 * @ns_segctor_sem: semaphore protecting log write
73 * @ns_dat: DAT file inode
74 * @ns_cpfile: checkpoint file inode
75 * @ns_sufile: segusage file inode
76 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
77 * @ns_cptree_lock: lock protecting @ns_cptree
78 * @ns_dirty_files: list of dirty files
79 * @ns_inode_lock: lock protecting @ns_dirty_files
80 * @ns_gc_inodes: dummy inodes to keep live blocks
81 * @ns_next_generation: next generation number for inodes
82 * @ns_next_gen_lock: lock protecting @ns_next_generation
83 * @ns_mount_opt: mount options
84 * @ns_resuid: uid for reserved blocks
85 * @ns_resgid: gid for reserved blocks
86 * @ns_interval: checkpoint creation interval
87 * @ns_watermark: watermark for the number of dirty buffers
88 * @ns_blocksize_bits: bit length of block size
89 * @ns_blocksize: block size
90 * @ns_nsegments: number of segments in filesystem
91 * @ns_blocks_per_segment: number of blocks per segment
92 * @ns_r_segments_percentage: reserved segments percentage
93 * @ns_nrsvsegs: number of reserved segments
94 * @ns_first_data_block: block number of first data block
95 * @ns_inode_size: size of on-disk inode
96 * @ns_first_ino: first not-special inode number
97 * @ns_crc_seed: seed value of CRC32 calculation
98 * @ns_dev_kobj: /sys/fs/<nilfs>/<device>
99 * @ns_dev_kobj_unregister: completion state
100 * @ns_dev_subgroups: <device> subgroups pointer
101 */
102 struct the_nilfs {
103 unsigned long ns_flags;
104 int ns_flushed_device;
105
106 struct super_block *ns_sb;
107 struct block_device *ns_bdev;
108 struct rw_semaphore ns_sem;
109 struct mutex ns_snapshot_mount_mutex;
110
111 /*
112 * used for
113 * - loading the latest checkpoint exclusively.
114 * - allocating a new full segment.
115 */
116 struct buffer_head *ns_sbh[2];
117 struct nilfs_super_block *ns_sbp[2];
118 time_t ns_sbwtime;
119 unsigned int ns_sbwcount;
120 unsigned int ns_sbsize;
121 unsigned int ns_mount_state;
122 unsigned int ns_sb_update_freq;
123
124 /*
125 * The following fields are updated by a writable FS-instance.
126 * These fields are protected by ns_segctor_sem outside load_nilfs().
127 */
128 u64 ns_seg_seq;
129 __u64 ns_segnum;
130 __u64 ns_nextnum;
131 unsigned long ns_pseg_offset;
132 __u64 ns_cno;
133 time_t ns_ctime;
134 time_t ns_nongc_ctime;
135 atomic_t ns_ndirtyblks;
136
137 /*
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.
141 */
142 spinlock_t ns_last_segment_lock;
143 sector_t ns_last_pseg;
144 u64 ns_last_seq;
145 __u64 ns_last_cno;
146 u64 ns_prot_seq;
147 u64 ns_prev_seq;
148
149 struct nilfs_sc_info *ns_writer;
150 struct rw_semaphore ns_segctor_sem;
151
152 /*
153 * Following fields are lock free except for the period before
154 * the_nilfs is initialized.
155 */
156 struct inode *ns_dat;
157 struct inode *ns_cpfile;
158 struct inode *ns_sufile;
159
160 /* Checkpoint tree */
161 struct rb_root ns_cptree;
162 spinlock_t ns_cptree_lock;
163
164 /* Dirty inode list */
165 struct list_head ns_dirty_files;
166 spinlock_t ns_inode_lock;
167
168 /* GC inode list */
169 struct list_head ns_gc_inodes;
170
171 /* Inode allocator */
172 u32 ns_next_generation;
173 spinlock_t ns_next_gen_lock;
174
175 /* Mount options */
176 unsigned long ns_mount_opt;
177
178 uid_t ns_resuid;
179 gid_t ns_resgid;
180 unsigned long ns_interval;
181 unsigned long ns_watermark;
182
183 /* Disk layout information (static) */
184 unsigned int ns_blocksize_bits;
185 unsigned int ns_blocksize;
186 unsigned long ns_nsegments;
187 unsigned long ns_blocks_per_segment;
188 unsigned long ns_r_segments_percentage;
189 unsigned long ns_nrsvsegs;
190 unsigned long ns_first_data_block;
191 int ns_inode_size;
192 int ns_first_ino;
193 u32 ns_crc_seed;
194
195 /* /sys/fs/<nilfs>/<device> */
196 struct kobject ns_dev_kobj;
197 struct completion ns_dev_kobj_unregister;
198 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups;
199 };
200
201 #define THE_NILFS_FNS(bit, name) \
202 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
203 { \
204 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
205 } \
206 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
207 { \
208 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
209 } \
210 static inline int nilfs_##name(struct the_nilfs *nilfs) \
211 { \
212 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
213 }
214
215 THE_NILFS_FNS(INIT, init)
216 THE_NILFS_FNS(DISCONTINUED, discontinued)
217 THE_NILFS_FNS(GC_RUNNING, gc_running)
218 THE_NILFS_FNS(SB_DIRTY, sb_dirty)
219
220 /*
221 * Mount option operations
222 */
223 #define nilfs_clear_opt(nilfs, opt) \
224 ((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt)
225 #define nilfs_set_opt(nilfs, opt) \
226 ((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt)
227 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
228 #define nilfs_write_opt(nilfs, mask, opt) \
229 ((nilfs)->ns_mount_opt = \
230 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \
231 NILFS_MOUNT_##opt)) \
232
233 /**
234 * struct nilfs_root - nilfs root object
235 * @cno: checkpoint number
236 * @rb_node: red-black tree node
237 * @count: refcount of this structure
238 * @nilfs: nilfs object
239 * @ifile: inode file
240 * @inodes_count: number of inodes
241 * @blocks_count: number of blocks
242 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot>
243 * @snapshot_kobj_unregister: completion state for kernel object
244 */
245 struct nilfs_root {
246 __u64 cno;
247 struct rb_node rb_node;
248
249 atomic_t count;
250 struct the_nilfs *nilfs;
251 struct inode *ifile;
252
253 atomic64_t inodes_count;
254 atomic64_t blocks_count;
255
256 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */
257 struct kobject snapshot_kobj;
258 struct completion snapshot_kobj_unregister;
259 };
260
261 /* Special checkpoint number */
262 #define NILFS_CPTREE_CURRENT_CNO 0
263
264 /* Minimum interval of periodical update of superblocks (in seconds) */
265 #define NILFS_SB_FREQ 10
266
nilfs_sb_need_update(struct the_nilfs * nilfs)267 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
268 {
269 u64 t = get_seconds();
270
271 return t < nilfs->ns_sbwtime ||
272 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq;
273 }
274
nilfs_sb_will_flip(struct the_nilfs * nilfs)275 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
276 {
277 int flip_bits = nilfs->ns_sbwcount & 0x0FL;
278
279 return (flip_bits != 0x08 && flip_bits != 0x0F);
280 }
281
282 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
283 struct the_nilfs *alloc_nilfs(struct super_block *sb);
284 void destroy_nilfs(struct the_nilfs *nilfs);
285 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data);
286 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
287 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs);
288 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs);
289 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
290 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
291 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
292 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
293 __u64 cno);
294 void nilfs_put_root(struct nilfs_root *root);
295 int nilfs_near_disk_full(struct the_nilfs *);
296 void nilfs_fall_back_super_block(struct the_nilfs *);
297 void nilfs_swap_super_block(struct the_nilfs *);
298
299
nilfs_get_root(struct nilfs_root * root)300 static inline void nilfs_get_root(struct nilfs_root *root)
301 {
302 atomic_inc(&root->count);
303 }
304
nilfs_valid_fs(struct the_nilfs * nilfs)305 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
306 {
307 unsigned int valid_fs;
308
309 down_read(&nilfs->ns_sem);
310 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
311 up_read(&nilfs->ns_sem);
312 return valid_fs;
313 }
314
315 static inline void
nilfs_get_segment_range(struct the_nilfs * nilfs,__u64 segnum,sector_t * seg_start,sector_t * seg_end)316 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
317 sector_t *seg_start, sector_t *seg_end)
318 {
319 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
320 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
321 if (segnum == 0)
322 *seg_start = nilfs->ns_first_data_block;
323 }
324
325 static inline sector_t
nilfs_get_segment_start_blocknr(struct the_nilfs * nilfs,__u64 segnum)326 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
327 {
328 return (segnum == 0) ? nilfs->ns_first_data_block :
329 (sector_t)nilfs->ns_blocks_per_segment * segnum;
330 }
331
332 static inline __u64
nilfs_get_segnum_of_block(struct the_nilfs * nilfs,sector_t blocknr)333 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
334 {
335 sector_t segnum = blocknr;
336
337 sector_div(segnum, nilfs->ns_blocks_per_segment);
338 return segnum;
339 }
340
341 static inline void
nilfs_terminate_segment(struct the_nilfs * nilfs,sector_t seg_start,sector_t seg_end)342 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
343 sector_t seg_end)
344 {
345 /* terminate the current full segment (used in case of I/O-error) */
346 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
347 }
348
nilfs_shift_to_next_segment(struct the_nilfs * nilfs)349 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
350 {
351 /* move forward with a full segment */
352 nilfs->ns_segnum = nilfs->ns_nextnum;
353 nilfs->ns_pseg_offset = 0;
354 nilfs->ns_seg_seq++;
355 }
356
nilfs_last_cno(struct the_nilfs * nilfs)357 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
358 {
359 __u64 cno;
360
361 spin_lock(&nilfs->ns_last_segment_lock);
362 cno = nilfs->ns_last_cno;
363 spin_unlock(&nilfs->ns_last_segment_lock);
364 return cno;
365 }
366
nilfs_segment_is_active(struct the_nilfs * nilfs,__u64 n)367 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
368 {
369 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
370 }
371
nilfs_flush_device(struct the_nilfs * nilfs)372 static inline int nilfs_flush_device(struct the_nilfs *nilfs)
373 {
374 int err;
375
376 if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device)
377 return 0;
378
379 nilfs->ns_flushed_device = 1;
380 /*
381 * the store to ns_flushed_device must not be reordered after
382 * blkdev_issue_flush().
383 */
384 smp_wmb();
385
386 err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL, NULL);
387 if (err != -EIO)
388 err = 0;
389 return err;
390 }
391
392 #endif /* _THE_NILFS_H */
393