1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * the_nilfs.h - the_nilfs shared structure.
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Written by Ryusuke Konishi.
8 *
9 */
10
11 #ifndef _THE_NILFS_H
12 #define _THE_NILFS_H
13
14 #include <linux/types.h>
15 #include <linux/buffer_head.h>
16 #include <linux/rbtree.h>
17 #include <linux/fs.h>
18 #include <linux/blkdev.h>
19 #include <linux/backing-dev.h>
20 #include <linux/slab.h>
21 #include <linux/refcount.h>
22
23 struct nilfs_sc_info;
24 struct nilfs_sysfs_dev_subgroups;
25
26 /* the_nilfs struct */
27 enum {
28 THE_NILFS_INIT = 0, /* Information from super_block is set */
29 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
30 THE_NILFS_GC_RUNNING, /* gc process is running */
31 THE_NILFS_SB_DIRTY, /* super block is dirty */
32 };
33
34 /**
35 * struct the_nilfs - struct to supervise multiple nilfs mount points
36 * @ns_flags: flags
37 * @ns_flushed_device: flag indicating if all volatile data was flushed
38 * @ns_sb: back pointer to super block instance
39 * @ns_bdev: block device
40 * @ns_sem: semaphore for shared states
41 * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts
42 * @ns_sbh: buffer heads of on-disk super blocks
43 * @ns_sbp: pointers to super block data
44 * @ns_sbwtime: previous write time of super block
45 * @ns_sbwcount: write count of super block
46 * @ns_sbsize: size of valid data in super block
47 * @ns_mount_state: file system state
48 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds)
49 * @ns_seg_seq: segment sequence counter
50 * @ns_segnum: index number of the latest full segment.
51 * @ns_nextnum: index number of the full segment index to be used next
52 * @ns_pseg_offset: offset of next partial segment in the current full segment
53 * @ns_cno: next checkpoint number
54 * @ns_ctime: write time of the last segment
55 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
56 * @ns_ndirtyblks: Number of dirty data blocks
57 * @ns_last_segment_lock: lock protecting fields for the latest segment
58 * @ns_last_pseg: start block number of the latest segment
59 * @ns_last_seq: sequence value of the latest segment
60 * @ns_last_cno: checkpoint number of the latest segment
61 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
62 * @ns_prev_seq: base sequence number used to decide if advance log cursor
63 * @ns_writer: log writer
64 * @ns_segctor_sem: semaphore protecting log write
65 * @ns_dat: DAT file inode
66 * @ns_cpfile: checkpoint file inode
67 * @ns_sufile: segusage file inode
68 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
69 * @ns_cptree_lock: lock protecting @ns_cptree
70 * @ns_dirty_files: list of dirty files
71 * @ns_inode_lock: lock protecting @ns_dirty_files
72 * @ns_gc_inodes: dummy inodes to keep live blocks
73 * @ns_next_generation: next generation number for inodes
74 * @ns_next_gen_lock: lock protecting @ns_next_generation
75 * @ns_mount_opt: mount options
76 * @ns_resuid: uid for reserved blocks
77 * @ns_resgid: gid for reserved blocks
78 * @ns_interval: checkpoint creation interval
79 * @ns_watermark: watermark for the number of dirty buffers
80 * @ns_blocksize_bits: bit length of block size
81 * @ns_blocksize: block size
82 * @ns_nsegments: number of segments in filesystem
83 * @ns_blocks_per_segment: number of blocks per segment
84 * @ns_r_segments_percentage: reserved segments percentage
85 * @ns_nrsvsegs: number of reserved segments
86 * @ns_first_data_block: block number of first data block
87 * @ns_inode_size: size of on-disk inode
88 * @ns_first_ino: first not-special inode number
89 * @ns_crc_seed: seed value of CRC32 calculation
90 * @ns_dev_kobj: /sys/fs/<nilfs>/<device>
91 * @ns_dev_kobj_unregister: completion state
92 * @ns_dev_subgroups: <device> subgroups pointer
93 */
94 struct the_nilfs {
95 unsigned long ns_flags;
96 int ns_flushed_device;
97
98 struct super_block *ns_sb;
99 struct block_device *ns_bdev;
100 struct rw_semaphore ns_sem;
101 struct mutex ns_snapshot_mount_mutex;
102
103 /*
104 * used for
105 * - loading the latest checkpoint exclusively.
106 * - allocating a new full segment.
107 */
108 struct buffer_head *ns_sbh[2];
109 struct nilfs_super_block *ns_sbp[2];
110 time64_t ns_sbwtime;
111 unsigned int ns_sbwcount;
112 unsigned int ns_sbsize;
113 unsigned int ns_mount_state;
114 unsigned int ns_sb_update_freq;
115
116 /*
117 * The following fields are updated by a writable FS-instance.
118 * These fields are protected by ns_segctor_sem outside load_nilfs().
119 */
120 u64 ns_seg_seq;
121 __u64 ns_segnum;
122 __u64 ns_nextnum;
123 unsigned long ns_pseg_offset;
124 __u64 ns_cno;
125 time64_t ns_ctime;
126 time64_t ns_nongc_ctime;
127 atomic_t ns_ndirtyblks;
128
129 /*
130 * The following fields hold information on the latest partial segment
131 * written to disk with a super root. These fields are protected by
132 * ns_last_segment_lock.
133 */
134 spinlock_t ns_last_segment_lock;
135 sector_t ns_last_pseg;
136 u64 ns_last_seq;
137 __u64 ns_last_cno;
138 u64 ns_prot_seq;
139 u64 ns_prev_seq;
140
141 struct nilfs_sc_info *ns_writer;
142 struct rw_semaphore ns_segctor_sem;
143
144 /*
145 * Following fields are lock free except for the period before
146 * the_nilfs is initialized.
147 */
148 struct inode *ns_dat;
149 struct inode *ns_cpfile;
150 struct inode *ns_sufile;
151
152 /* Checkpoint tree */
153 struct rb_root ns_cptree;
154 spinlock_t ns_cptree_lock;
155
156 /* Dirty inode list */
157 struct list_head ns_dirty_files;
158 spinlock_t ns_inode_lock;
159
160 /* GC inode list */
161 struct list_head ns_gc_inodes;
162
163 /* Inode allocator */
164 u32 ns_next_generation;
165 spinlock_t ns_next_gen_lock;
166
167 /* Mount options */
168 unsigned long ns_mount_opt;
169
170 uid_t ns_resuid;
171 gid_t ns_resgid;
172 unsigned long ns_interval;
173 unsigned long ns_watermark;
174
175 /* Disk layout information (static) */
176 unsigned int ns_blocksize_bits;
177 unsigned int ns_blocksize;
178 unsigned long ns_nsegments;
179 unsigned long ns_blocks_per_segment;
180 unsigned long ns_r_segments_percentage;
181 unsigned long ns_nrsvsegs;
182 unsigned long ns_first_data_block;
183 int ns_inode_size;
184 int ns_first_ino;
185 u32 ns_crc_seed;
186
187 /* /sys/fs/<nilfs>/<device> */
188 struct kobject ns_dev_kobj;
189 struct completion ns_dev_kobj_unregister;
190 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups;
191 };
192
193 #define THE_NILFS_FNS(bit, name) \
194 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
195 { \
196 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
197 } \
198 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
199 { \
200 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
201 } \
202 static inline int nilfs_##name(struct the_nilfs *nilfs) \
203 { \
204 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
205 }
206
207 THE_NILFS_FNS(INIT, init)
208 THE_NILFS_FNS(DISCONTINUED, discontinued)
209 THE_NILFS_FNS(GC_RUNNING, gc_running)
210 THE_NILFS_FNS(SB_DIRTY, sb_dirty)
211
212 /*
213 * Mount option operations
214 */
215 #define nilfs_clear_opt(nilfs, opt) \
216 ((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt)
217 #define nilfs_set_opt(nilfs, opt) \
218 ((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt)
219 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
220 #define nilfs_write_opt(nilfs, mask, opt) \
221 ((nilfs)->ns_mount_opt = \
222 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \
223 NILFS_MOUNT_##opt)) \
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 * @inodes_count: number of inodes
233 * @blocks_count: number of blocks
234 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot>
235 * @snapshot_kobj_unregister: completion state for kernel object
236 */
237 struct nilfs_root {
238 __u64 cno;
239 struct rb_node rb_node;
240
241 refcount_t count;
242 struct the_nilfs *nilfs;
243 struct inode *ifile;
244
245 atomic64_t inodes_count;
246 atomic64_t blocks_count;
247
248 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */
249 struct kobject snapshot_kobj;
250 struct completion snapshot_kobj_unregister;
251 };
252
253 /* Special checkpoint number */
254 #define NILFS_CPTREE_CURRENT_CNO 0
255
256 /* Minimum interval of periodical update of superblocks (in seconds) */
257 #define NILFS_SB_FREQ 10
258
nilfs_sb_need_update(struct the_nilfs * nilfs)259 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
260 {
261 u64 t = ktime_get_real_seconds();
262
263 return t < nilfs->ns_sbwtime ||
264 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq;
265 }
266
nilfs_sb_will_flip(struct the_nilfs * nilfs)267 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
268 {
269 int flip_bits = nilfs->ns_sbwcount & 0x0FL;
270
271 return (flip_bits != 0x08 && flip_bits != 0x0F);
272 }
273
274 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
275 struct the_nilfs *alloc_nilfs(struct super_block *sb);
276 void destroy_nilfs(struct the_nilfs *nilfs);
277 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data);
278 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
279 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs);
280 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs);
281 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
282 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
283 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
284 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
285 __u64 cno);
286 void nilfs_put_root(struct nilfs_root *root);
287 int nilfs_near_disk_full(struct the_nilfs *);
288 void nilfs_fall_back_super_block(struct the_nilfs *);
289 void nilfs_swap_super_block(struct the_nilfs *);
290
291
nilfs_get_root(struct nilfs_root * root)292 static inline void nilfs_get_root(struct nilfs_root *root)
293 {
294 refcount_inc(&root->count);
295 }
296
nilfs_valid_fs(struct the_nilfs * nilfs)297 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
298 {
299 unsigned int valid_fs;
300
301 down_read(&nilfs->ns_sem);
302 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
303 up_read(&nilfs->ns_sem);
304 return valid_fs;
305 }
306
307 static inline void
nilfs_get_segment_range(struct the_nilfs * nilfs,__u64 segnum,sector_t * seg_start,sector_t * seg_end)308 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
309 sector_t *seg_start, sector_t *seg_end)
310 {
311 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
312 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
313 if (segnum == 0)
314 *seg_start = nilfs->ns_first_data_block;
315 }
316
317 static inline sector_t
nilfs_get_segment_start_blocknr(struct the_nilfs * nilfs,__u64 segnum)318 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
319 {
320 return (segnum == 0) ? nilfs->ns_first_data_block :
321 (sector_t)nilfs->ns_blocks_per_segment * segnum;
322 }
323
324 static inline __u64
nilfs_get_segnum_of_block(struct the_nilfs * nilfs,sector_t blocknr)325 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
326 {
327 sector_t segnum = blocknr;
328
329 sector_div(segnum, nilfs->ns_blocks_per_segment);
330 return segnum;
331 }
332
333 static inline void
nilfs_terminate_segment(struct the_nilfs * nilfs,sector_t seg_start,sector_t seg_end)334 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
335 sector_t seg_end)
336 {
337 /* terminate the current full segment (used in case of I/O-error) */
338 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
339 }
340
nilfs_shift_to_next_segment(struct the_nilfs * nilfs)341 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
342 {
343 /* move forward with a full segment */
344 nilfs->ns_segnum = nilfs->ns_nextnum;
345 nilfs->ns_pseg_offset = 0;
346 nilfs->ns_seg_seq++;
347 }
348
nilfs_last_cno(struct the_nilfs * nilfs)349 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
350 {
351 __u64 cno;
352
353 spin_lock(&nilfs->ns_last_segment_lock);
354 cno = nilfs->ns_last_cno;
355 spin_unlock(&nilfs->ns_last_segment_lock);
356 return cno;
357 }
358
nilfs_segment_is_active(struct the_nilfs * nilfs,__u64 n)359 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
360 {
361 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
362 }
363
nilfs_flush_device(struct the_nilfs * nilfs)364 static inline int nilfs_flush_device(struct the_nilfs *nilfs)
365 {
366 int err;
367
368 if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device)
369 return 0;
370
371 nilfs->ns_flushed_device = 1;
372 /*
373 * the store to ns_flushed_device must not be reordered after
374 * blkdev_issue_flush().
375 */
376 smp_wmb();
377
378 err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL, NULL);
379 if (err != -EIO)
380 err = 0;
381 return err;
382 }
383
384 #endif /* _THE_NILFS_H */
385