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 struct nilfs_sysfs_dev_subgroups;
37
38 /* the_nilfs struct */
39 enum {
40 THE_NILFS_INIT = 0, /* Information from super_block is set */
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 */
44 };
45
46 /**
47 * struct the_nilfs - struct to supervise multiple nilfs mount points
48 * @ns_flags: flags
49 * @ns_flushed_device: flag indicating if all volatile data was flushed
50 * @ns_bdev: block device
51 * @ns_sem: semaphore for shared states
52 * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts
53 * @ns_sbh: buffer heads of on-disk super blocks
54 * @ns_sbp: pointers to super block data
55 * @ns_sbwtime: previous write time of super block
56 * @ns_sbwcount: write count of super block
57 * @ns_sbsize: size of valid data in super block
58 * @ns_mount_state: file system state
59 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds)
60 * @ns_seg_seq: segment sequence counter
61 * @ns_segnum: index number of the latest full segment.
62 * @ns_nextnum: index number of the full segment index to be used next
63 * @ns_pseg_offset: offset of next partial segment in the current full segment
64 * @ns_cno: next checkpoint number
65 * @ns_ctime: write time of the last segment
66 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
67 * @ns_ndirtyblks: Number of dirty data blocks
68 * @ns_last_segment_lock: lock protecting fields for the latest segment
69 * @ns_last_pseg: start block number of the latest segment
70 * @ns_last_seq: sequence value of the latest segment
71 * @ns_last_cno: checkpoint number of the latest segment
72 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
73 * @ns_prev_seq: base sequence number used to decide if advance log cursor
74 * @ns_writer: log writer
75 * @ns_segctor_sem: semaphore protecting log write
76 * @ns_dat: DAT file inode
77 * @ns_cpfile: checkpoint file inode
78 * @ns_sufile: segusage file inode
79 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
80 * @ns_cptree_lock: lock protecting @ns_cptree
81 * @ns_dirty_files: list of dirty files
82 * @ns_inode_lock: lock protecting @ns_dirty_files
83 * @ns_gc_inodes: dummy inodes to keep live blocks
84 * @ns_next_generation: next generation number for inodes
85 * @ns_next_gen_lock: lock protecting @ns_next_generation
86 * @ns_mount_opt: mount options
87 * @ns_resuid: uid for reserved blocks
88 * @ns_resgid: gid for reserved blocks
89 * @ns_interval: checkpoint creation interval
90 * @ns_watermark: watermark for the number of dirty buffers
91 * @ns_blocksize_bits: bit length of block size
92 * @ns_blocksize: block size
93 * @ns_nsegments: number of segments in filesystem
94 * @ns_blocks_per_segment: number of blocks per segment
95 * @ns_r_segments_percentage: reserved segments percentage
96 * @ns_nrsvsegs: number of reserved segments
97 * @ns_first_data_block: block number of first data block
98 * @ns_inode_size: size of on-disk inode
99 * @ns_first_ino: first not-special inode number
100 * @ns_crc_seed: seed value of CRC32 calculation
101 * @ns_dev_kobj: /sys/fs/<nilfs>/<device>
102 * @ns_dev_kobj_unregister: completion state
103 * @ns_dev_subgroups: <device> subgroups pointer
104 */
105 struct the_nilfs {
106 unsigned long ns_flags;
107 int ns_flushed_device;
108
109 struct block_device *ns_bdev;
110 struct rw_semaphore ns_sem;
111 struct mutex ns_snapshot_mount_mutex;
112
113 /*
114 * used for
115 * - loading the latest checkpoint exclusively.
116 * - allocating a new full segment.
117 */
118 struct buffer_head *ns_sbh[2];
119 struct nilfs_super_block *ns_sbp[2];
120 time_t ns_sbwtime;
121 unsigned ns_sbwcount;
122 unsigned ns_sbsize;
123 unsigned ns_mount_state;
124 unsigned ns_sb_update_freq;
125
126 /*
127 * Following fields are dedicated to a writable FS-instance.
128 * Except for the period seeking checkpoint, code outside the segment
129 * constructor must lock a segment semaphore while accessing these
130 * fields.
131 * The writable FS-instance is sole during a lifetime of the_nilfs.
132 */
133 u64 ns_seg_seq;
134 __u64 ns_segnum;
135 __u64 ns_nextnum;
136 unsigned long ns_pseg_offset;
137 __u64 ns_cno;
138 time_t ns_ctime;
139 time_t ns_nongc_ctime;
140 atomic_t ns_ndirtyblks;
141
142 /*
143 * The following fields hold information on the latest partial segment
144 * written to disk with a super root. These fields are protected by
145 * ns_last_segment_lock.
146 */
147 spinlock_t ns_last_segment_lock;
148 sector_t ns_last_pseg;
149 u64 ns_last_seq;
150 __u64 ns_last_cno;
151 u64 ns_prot_seq;
152 u64 ns_prev_seq;
153
154 struct nilfs_sc_info *ns_writer;
155 struct rw_semaphore ns_segctor_sem;
156
157 /*
158 * Following fields are lock free except for the period before
159 * the_nilfs is initialized.
160 */
161 struct inode *ns_dat;
162 struct inode *ns_cpfile;
163 struct inode *ns_sufile;
164
165 /* Checkpoint tree */
166 struct rb_root ns_cptree;
167 spinlock_t ns_cptree_lock;
168
169 /* Dirty inode list */
170 struct list_head ns_dirty_files;
171 spinlock_t ns_inode_lock;
172
173 /* GC inode list */
174 struct list_head ns_gc_inodes;
175
176 /* Inode allocator */
177 u32 ns_next_generation;
178 spinlock_t ns_next_gen_lock;
179
180 /* Mount options */
181 unsigned long ns_mount_opt;
182
183 uid_t ns_resuid;
184 gid_t ns_resgid;
185 unsigned long ns_interval;
186 unsigned long ns_watermark;
187
188 /* Disk layout information (static) */
189 unsigned int ns_blocksize_bits;
190 unsigned int ns_blocksize;
191 unsigned long ns_nsegments;
192 unsigned long ns_blocks_per_segment;
193 unsigned long ns_r_segments_percentage;
194 unsigned long ns_nrsvsegs;
195 unsigned long ns_first_data_block;
196 int ns_inode_size;
197 int ns_first_ino;
198 u32 ns_crc_seed;
199
200 /* /sys/fs/<nilfs>/<device> */
201 struct kobject ns_dev_kobj;
202 struct completion ns_dev_kobj_unregister;
203 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups;
204 };
205
206 #define THE_NILFS_FNS(bit, name) \
207 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
208 { \
209 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
210 } \
211 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
212 { \
213 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
214 } \
215 static inline int nilfs_##name(struct the_nilfs *nilfs) \
216 { \
217 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
218 }
219
220 THE_NILFS_FNS(INIT, init)
221 THE_NILFS_FNS(DISCONTINUED, discontinued)
222 THE_NILFS_FNS(GC_RUNNING, gc_running)
223 THE_NILFS_FNS(SB_DIRTY, sb_dirty)
224
225 /*
226 * Mount option operations
227 */
228 #define nilfs_clear_opt(nilfs, opt) \
229 do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)
230 #define nilfs_set_opt(nilfs, opt) \
231 do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0)
232 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
233 #define nilfs_write_opt(nilfs, mask, opt) \
234 do { (nilfs)->ns_mount_opt = \
235 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \
236 NILFS_MOUNT_##opt); \
237 } while (0)
238
239 /**
240 * struct nilfs_root - nilfs root object
241 * @cno: checkpoint number
242 * @rb_node: red-black tree node
243 * @count: refcount of this structure
244 * @nilfs: nilfs object
245 * @ifile: inode file
246 * @inodes_count: number of inodes
247 * @blocks_count: number of blocks
248 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot>
249 * @snapshot_kobj_unregister: completion state for kernel object
250 */
251 struct nilfs_root {
252 __u64 cno;
253 struct rb_node rb_node;
254
255 atomic_t count;
256 struct the_nilfs *nilfs;
257 struct inode *ifile;
258
259 atomic64_t inodes_count;
260 atomic64_t blocks_count;
261
262 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */
263 struct kobject snapshot_kobj;
264 struct completion snapshot_kobj_unregister;
265 };
266
267 /* Special checkpoint number */
268 #define NILFS_CPTREE_CURRENT_CNO 0
269
270 /* Minimum interval of periodical update of superblocks (in seconds) */
271 #define NILFS_SB_FREQ 10
272
nilfs_sb_need_update(struct the_nilfs * nilfs)273 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
274 {
275 u64 t = get_seconds();
276 return t < nilfs->ns_sbwtime ||
277 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq;
278 }
279
nilfs_sb_will_flip(struct the_nilfs * nilfs)280 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
281 {
282 int flip_bits = nilfs->ns_sbwcount & 0x0FL;
283 return (flip_bits != 0x08 && flip_bits != 0x0F);
284 }
285
286 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
287 struct the_nilfs *alloc_nilfs(struct block_device *bdev);
288 void destroy_nilfs(struct the_nilfs *nilfs);
289 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data);
290 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
291 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs);
292 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs);
293 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
294 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
295 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
296 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
297 __u64 cno);
298 void nilfs_put_root(struct nilfs_root *root);
299 int nilfs_near_disk_full(struct the_nilfs *);
300 void nilfs_fall_back_super_block(struct the_nilfs *);
301 void nilfs_swap_super_block(struct the_nilfs *);
302
303
nilfs_get_root(struct nilfs_root * root)304 static inline void nilfs_get_root(struct nilfs_root *root)
305 {
306 atomic_inc(&root->count);
307 }
308
nilfs_valid_fs(struct the_nilfs * nilfs)309 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
310 {
311 unsigned valid_fs;
312
313 down_read(&nilfs->ns_sem);
314 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
315 up_read(&nilfs->ns_sem);
316 return valid_fs;
317 }
318
319 static inline void
nilfs_get_segment_range(struct the_nilfs * nilfs,__u64 segnum,sector_t * seg_start,sector_t * seg_end)320 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
321 sector_t *seg_start, sector_t *seg_end)
322 {
323 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
324 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
325 if (segnum == 0)
326 *seg_start = nilfs->ns_first_data_block;
327 }
328
329 static inline sector_t
nilfs_get_segment_start_blocknr(struct the_nilfs * nilfs,__u64 segnum)330 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
331 {
332 return (segnum == 0) ? nilfs->ns_first_data_block :
333 (sector_t)nilfs->ns_blocks_per_segment * segnum;
334 }
335
336 static inline __u64
nilfs_get_segnum_of_block(struct the_nilfs * nilfs,sector_t blocknr)337 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
338 {
339 sector_t segnum = blocknr;
340
341 sector_div(segnum, nilfs->ns_blocks_per_segment);
342 return segnum;
343 }
344
345 static inline void
nilfs_terminate_segment(struct the_nilfs * nilfs,sector_t seg_start,sector_t seg_end)346 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
347 sector_t seg_end)
348 {
349 /* terminate the current full segment (used in case of I/O-error) */
350 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
351 }
352
nilfs_shift_to_next_segment(struct the_nilfs * nilfs)353 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
354 {
355 /* move forward with a full segment */
356 nilfs->ns_segnum = nilfs->ns_nextnum;
357 nilfs->ns_pseg_offset = 0;
358 nilfs->ns_seg_seq++;
359 }
360
nilfs_last_cno(struct the_nilfs * nilfs)361 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
362 {
363 __u64 cno;
364
365 spin_lock(&nilfs->ns_last_segment_lock);
366 cno = nilfs->ns_last_cno;
367 spin_unlock(&nilfs->ns_last_segment_lock);
368 return cno;
369 }
370
nilfs_segment_is_active(struct the_nilfs * nilfs,__u64 n)371 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
372 {
373 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
374 }
375
nilfs_flush_device(struct the_nilfs * nilfs)376 static inline int nilfs_flush_device(struct the_nilfs *nilfs)
377 {
378 int err;
379
380 if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device)
381 return 0;
382
383 nilfs->ns_flushed_device = 1;
384 /*
385 * the store to ns_flushed_device must not be reordered after
386 * blkdev_issue_flush().
387 */
388 smp_wmb();
389
390 err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL, NULL);
391 if (err != -EIO)
392 err = 0;
393 return err;
394 }
395
396 #endif /* _THE_NILFS_H */
397