1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * 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 THE_NILFS_PURGING, /* disposing dirty files for cleanup */
33 };
34
35 /**
36 * struct the_nilfs - struct to supervise multiple nilfs mount points
37 * @ns_flags: flags
38 * @ns_flushed_device: flag indicating if all volatile data was flushed
39 * @ns_sb: back pointer to super block instance
40 * @ns_bdev: block device
41 * @ns_sem: semaphore for shared states
42 * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts
43 * @ns_sbh: buffer heads of on-disk super blocks
44 * @ns_sbp: pointers to super block data
45 * @ns_sbwtime: previous write time of super block
46 * @ns_sbwcount: write count of super block
47 * @ns_sbsize: size of valid data in super block
48 * @ns_mount_state: file system state
49 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds)
50 * @ns_seg_seq: segment sequence counter
51 * @ns_segnum: index number of the latest full segment.
52 * @ns_nextnum: index number of the full segment index to be used next
53 * @ns_pseg_offset: offset of next partial segment in the current full segment
54 * @ns_cno: next checkpoint number
55 * @ns_ctime: write time of the last segment
56 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
57 * @ns_ndirtyblks: Number of dirty data blocks
58 * @ns_last_segment_lock: lock protecting fields for the latest segment
59 * @ns_last_pseg: start block number of the latest segment
60 * @ns_last_seq: sequence value of the latest segment
61 * @ns_last_cno: checkpoint number of the latest segment
62 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
63 * @ns_prev_seq: base sequence number used to decide if advance log cursor
64 * @ns_writer: log writer
65 * @ns_segctor_sem: semaphore protecting log write
66 * @ns_dat: DAT file inode
67 * @ns_cpfile: checkpoint file inode
68 * @ns_sufile: segusage file inode
69 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
70 * @ns_cptree_lock: lock protecting @ns_cptree
71 * @ns_dirty_files: list of dirty files
72 * @ns_inode_lock: lock protecting @ns_dirty_files
73 * @ns_gc_inodes: dummy inodes to keep live blocks
74 * @ns_mount_opt: mount options
75 * @ns_resuid: uid for reserved blocks
76 * @ns_resgid: gid for reserved blocks
77 * @ns_interval: checkpoint creation interval
78 * @ns_watermark: watermark for the number of dirty buffers
79 * @ns_blocksize_bits: bit length of block size
80 * @ns_blocksize: block size
81 * @ns_nsegments: number of segments in filesystem
82 * @ns_blocks_per_segment: number of blocks per segment
83 * @ns_r_segments_percentage: reserved segments percentage
84 * @ns_nrsvsegs: number of reserved segments
85 * @ns_first_data_block: block number of first data block
86 * @ns_inode_size: size of on-disk inode
87 * @ns_first_ino: first not-special inode number
88 * @ns_crc_seed: seed value of CRC32 calculation
89 * @ns_dev_kobj: /sys/fs/<nilfs>/<device>
90 * @ns_dev_kobj_unregister: completion state
91 * @ns_dev_subgroups: <device> subgroups pointer
92 */
93 struct the_nilfs {
94 unsigned long ns_flags;
95 int ns_flushed_device;
96
97 struct super_block *ns_sb;
98 struct block_device *ns_bdev;
99 struct rw_semaphore ns_sem;
100 struct mutex ns_snapshot_mount_mutex;
101
102 /*
103 * used for
104 * - loading the latest checkpoint exclusively.
105 * - allocating a new full segment.
106 */
107 struct buffer_head *ns_sbh[2];
108 struct nilfs_super_block *ns_sbp[2];
109 time64_t ns_sbwtime;
110 unsigned int ns_sbwcount;
111 unsigned int ns_sbsize;
112 unsigned int ns_mount_state;
113 unsigned int ns_sb_update_freq;
114
115 /*
116 * The following fields are updated by a writable FS-instance.
117 * These fields are protected by ns_segctor_sem outside load_nilfs().
118 */
119 u64 ns_seg_seq;
120 __u64 ns_segnum;
121 __u64 ns_nextnum;
122 unsigned long ns_pseg_offset;
123 __u64 ns_cno;
124 time64_t ns_ctime;
125 time64_t ns_nongc_ctime;
126 atomic_t ns_ndirtyblks;
127
128 /*
129 * The following fields hold information on the latest partial segment
130 * written to disk with a super root. These fields are protected by
131 * ns_last_segment_lock.
132 */
133 spinlock_t ns_last_segment_lock;
134 sector_t ns_last_pseg;
135 u64 ns_last_seq;
136 __u64 ns_last_cno;
137 u64 ns_prot_seq;
138 u64 ns_prev_seq;
139
140 struct nilfs_sc_info *ns_writer;
141 struct rw_semaphore ns_segctor_sem;
142
143 /*
144 * Following fields are lock free except for the period before
145 * the_nilfs is initialized.
146 */
147 struct inode *ns_dat;
148 struct inode *ns_cpfile;
149 struct inode *ns_sufile;
150
151 /* Checkpoint tree */
152 struct rb_root ns_cptree;
153 spinlock_t ns_cptree_lock;
154
155 /* Dirty inode list */
156 struct list_head ns_dirty_files;
157 spinlock_t ns_inode_lock;
158
159 /* GC inode list */
160 struct list_head ns_gc_inodes;
161
162 /* Mount options */
163 unsigned long ns_mount_opt;
164
165 uid_t ns_resuid;
166 gid_t ns_resgid;
167 unsigned long ns_interval;
168 unsigned long ns_watermark;
169
170 /* Disk layout information (static) */
171 unsigned int ns_blocksize_bits;
172 unsigned int ns_blocksize;
173 unsigned long ns_nsegments;
174 unsigned long ns_blocks_per_segment;
175 unsigned long ns_r_segments_percentage;
176 unsigned long ns_nrsvsegs;
177 unsigned long ns_first_data_block;
178 int ns_inode_size;
179 unsigned int ns_first_ino;
180 u32 ns_crc_seed;
181
182 /* /sys/fs/<nilfs>/<device> */
183 struct kobject ns_dev_kobj;
184 struct completion ns_dev_kobj_unregister;
185 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups;
186 };
187
188 #define THE_NILFS_FNS(bit, name) \
189 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
190 { \
191 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
192 } \
193 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
194 { \
195 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
196 } \
197 static inline int nilfs_##name(struct the_nilfs *nilfs) \
198 { \
199 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
200 }
201
202 THE_NILFS_FNS(INIT, init)
203 THE_NILFS_FNS(DISCONTINUED, discontinued)
204 THE_NILFS_FNS(GC_RUNNING, gc_running)
205 THE_NILFS_FNS(SB_DIRTY, sb_dirty)
206 THE_NILFS_FNS(PURGING, purging)
207
208 /*
209 * Mount option operations
210 */
211 #define nilfs_clear_opt(nilfs, opt) \
212 ((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt)
213 #define nilfs_set_opt(nilfs, opt) \
214 ((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt)
215 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
216
217 /**
218 * struct nilfs_root - nilfs root object
219 * @cno: checkpoint number
220 * @rb_node: red-black tree node
221 * @count: refcount of this structure
222 * @nilfs: nilfs object
223 * @ifile: inode file
224 * @inodes_count: number of inodes
225 * @blocks_count: number of blocks
226 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot>
227 * @snapshot_kobj_unregister: completion state for kernel object
228 */
229 struct nilfs_root {
230 __u64 cno;
231 struct rb_node rb_node;
232
233 refcount_t count;
234 struct the_nilfs *nilfs;
235 struct inode *ifile;
236
237 atomic64_t inodes_count;
238 atomic64_t blocks_count;
239
240 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */
241 struct kobject snapshot_kobj;
242 struct completion snapshot_kobj_unregister;
243 };
244
245 /* Special checkpoint number */
246 #define NILFS_CPTREE_CURRENT_CNO 0
247
248 /* Minimum interval of periodical update of superblocks (in seconds) */
249 #define NILFS_SB_FREQ 10
250
nilfs_sb_need_update(struct the_nilfs * nilfs)251 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
252 {
253 u64 t = ktime_get_real_seconds();
254
255 return t < nilfs->ns_sbwtime ||
256 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq;
257 }
258
nilfs_sb_will_flip(struct the_nilfs * nilfs)259 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
260 {
261 int flip_bits = nilfs->ns_sbwcount & 0x0FL;
262
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 super_block *sb);
268 void destroy_nilfs(struct the_nilfs *nilfs);
269 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
270 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
271 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs);
272 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs);
273 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
274 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
275 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
276 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
277 __u64 cno);
278 void nilfs_put_root(struct nilfs_root *root);
279 int nilfs_near_disk_full(struct the_nilfs *);
280 void nilfs_fall_back_super_block(struct the_nilfs *);
281 void nilfs_swap_super_block(struct the_nilfs *);
282
283
nilfs_get_root(struct nilfs_root * root)284 static inline void nilfs_get_root(struct nilfs_root *root)
285 {
286 refcount_inc(&root->count);
287 }
288
nilfs_valid_fs(struct the_nilfs * nilfs)289 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
290 {
291 unsigned int valid_fs;
292
293 down_read(&nilfs->ns_sem);
294 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
295 up_read(&nilfs->ns_sem);
296 return valid_fs;
297 }
298
299 static inline void
nilfs_get_segment_range(struct the_nilfs * nilfs,__u64 segnum,sector_t * seg_start,sector_t * seg_end)300 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
301 sector_t *seg_start, sector_t *seg_end)
302 {
303 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
304 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
305 if (segnum == 0)
306 *seg_start = nilfs->ns_first_data_block;
307 }
308
309 static inline sector_t
nilfs_get_segment_start_blocknr(struct the_nilfs * nilfs,__u64 segnum)310 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
311 {
312 return (segnum == 0) ? nilfs->ns_first_data_block :
313 (sector_t)nilfs->ns_blocks_per_segment * segnum;
314 }
315
316 static inline __u64
nilfs_get_segnum_of_block(struct the_nilfs * nilfs,sector_t blocknr)317 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
318 {
319 sector_t segnum = blocknr;
320
321 sector_div(segnum, nilfs->ns_blocks_per_segment);
322 return segnum;
323 }
324
325 static inline void
nilfs_terminate_segment(struct the_nilfs * nilfs,sector_t seg_start,sector_t seg_end)326 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
327 sector_t seg_end)
328 {
329 /* terminate the current full segment (used in case of I/O-error) */
330 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
331 }
332
nilfs_shift_to_next_segment(struct the_nilfs * nilfs)333 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
334 {
335 /* move forward with a full segment */
336 nilfs->ns_segnum = nilfs->ns_nextnum;
337 nilfs->ns_pseg_offset = 0;
338 nilfs->ns_seg_seq++;
339 }
340
nilfs_last_cno(struct the_nilfs * nilfs)341 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
342 {
343 __u64 cno;
344
345 spin_lock(&nilfs->ns_last_segment_lock);
346 cno = nilfs->ns_last_cno;
347 spin_unlock(&nilfs->ns_last_segment_lock);
348 return cno;
349 }
350
nilfs_segment_is_active(struct the_nilfs * nilfs,__u64 n)351 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
352 {
353 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
354 }
355
nilfs_flush_device(struct the_nilfs * nilfs)356 static inline int nilfs_flush_device(struct the_nilfs *nilfs)
357 {
358 int err;
359
360 if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device)
361 return 0;
362
363 nilfs->ns_flushed_device = 1;
364 /*
365 * the store to ns_flushed_device must not be reordered after
366 * blkdev_issue_flush().
367 */
368 smp_wmb();
369
370 err = blkdev_issue_flush(nilfs->ns_bdev);
371 if (err != -EIO)
372 err = 0;
373 return err;
374 }
375
376 #endif /* _THE_NILFS_H */
377