xref: /openbmc/linux/fs/nilfs2/the_nilfs.h (revision 9194f8ca)
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_next_generation: next generation number for inodes
75  * @ns_next_gen_lock: lock protecting @ns_next_generation
76  * @ns_mount_opt: mount options
77  * @ns_resuid: uid for reserved blocks
78  * @ns_resgid: gid for reserved blocks
79  * @ns_interval: checkpoint creation interval
80  * @ns_watermark: watermark for the number of dirty buffers
81  * @ns_blocksize_bits: bit length of block size
82  * @ns_blocksize: block size
83  * @ns_nsegments: number of segments in filesystem
84  * @ns_blocks_per_segment: number of blocks per segment
85  * @ns_r_segments_percentage: reserved segments percentage
86  * @ns_nrsvsegs: number of reserved segments
87  * @ns_first_data_block: block number of first data block
88  * @ns_inode_size: size of on-disk inode
89  * @ns_first_ino: first not-special inode number
90  * @ns_crc_seed: seed value of CRC32 calculation
91  * @ns_dev_kobj: /sys/fs/<nilfs>/<device>
92  * @ns_dev_kobj_unregister: completion state
93  * @ns_dev_subgroups: <device> subgroups pointer
94  */
95 struct the_nilfs {
96 	unsigned long		ns_flags;
97 	int			ns_flushed_device;
98 
99 	struct super_block     *ns_sb;
100 	struct block_device    *ns_bdev;
101 	struct rw_semaphore	ns_sem;
102 	struct mutex		ns_snapshot_mount_mutex;
103 
104 	/*
105 	 * used for
106 	 * - loading the latest checkpoint exclusively.
107 	 * - allocating a new full segment.
108 	 */
109 	struct buffer_head     *ns_sbh[2];
110 	struct nilfs_super_block *ns_sbp[2];
111 	time64_t		ns_sbwtime;
112 	unsigned int		ns_sbwcount;
113 	unsigned int		ns_sbsize;
114 	unsigned int		ns_mount_state;
115 	unsigned int		ns_sb_update_freq;
116 
117 	/*
118 	 * The following fields are updated by a writable FS-instance.
119 	 * These fields are protected by ns_segctor_sem outside load_nilfs().
120 	 */
121 	u64			ns_seg_seq;
122 	__u64			ns_segnum;
123 	__u64			ns_nextnum;
124 	unsigned long		ns_pseg_offset;
125 	__u64			ns_cno;
126 	time64_t		ns_ctime;
127 	time64_t		ns_nongc_ctime;
128 	atomic_t		ns_ndirtyblks;
129 
130 	/*
131 	 * The following fields hold information on the latest partial segment
132 	 * written to disk with a super root.  These fields are protected by
133 	 * ns_last_segment_lock.
134 	 */
135 	spinlock_t		ns_last_segment_lock;
136 	sector_t		ns_last_pseg;
137 	u64			ns_last_seq;
138 	__u64			ns_last_cno;
139 	u64			ns_prot_seq;
140 	u64			ns_prev_seq;
141 
142 	struct nilfs_sc_info   *ns_writer;
143 	struct rw_semaphore	ns_segctor_sem;
144 
145 	/*
146 	 * Following fields are lock free except for the period before
147 	 * the_nilfs is initialized.
148 	 */
149 	struct inode	       *ns_dat;
150 	struct inode	       *ns_cpfile;
151 	struct inode	       *ns_sufile;
152 
153 	/* Checkpoint tree */
154 	struct rb_root		ns_cptree;
155 	spinlock_t		ns_cptree_lock;
156 
157 	/* Dirty inode list */
158 	struct list_head	ns_dirty_files;
159 	spinlock_t		ns_inode_lock;
160 
161 	/* GC inode list */
162 	struct list_head	ns_gc_inodes;
163 
164 	/* Inode allocator */
165 	u32			ns_next_generation;
166 	spinlock_t		ns_next_gen_lock;
167 
168 	/* Mount options */
169 	unsigned long		ns_mount_opt;
170 
171 	uid_t			ns_resuid;
172 	gid_t			ns_resgid;
173 	unsigned long		ns_interval;
174 	unsigned long		ns_watermark;
175 
176 	/* Disk layout information (static) */
177 	unsigned int		ns_blocksize_bits;
178 	unsigned int		ns_blocksize;
179 	unsigned long		ns_nsegments;
180 	unsigned long		ns_blocks_per_segment;
181 	unsigned long		ns_r_segments_percentage;
182 	unsigned long		ns_nrsvsegs;
183 	unsigned long		ns_first_data_block;
184 	int			ns_inode_size;
185 	unsigned int		ns_first_ino;
186 	u32			ns_crc_seed;
187 
188 	/* /sys/fs/<nilfs>/<device> */
189 	struct kobject ns_dev_kobj;
190 	struct completion ns_dev_kobj_unregister;
191 	struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups;
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 THE_NILFS_FNS(PURGING, purging)
213 
214 /*
215  * Mount option operations
216  */
217 #define nilfs_clear_opt(nilfs, opt)  \
218 	((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt)
219 #define nilfs_set_opt(nilfs, opt)  \
220 	((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt)
221 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
222 #define nilfs_write_opt(nilfs, mask, opt)				\
223 	((nilfs)->ns_mount_opt =					\
224 		(((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) |	\
225 		 NILFS_MOUNT_##opt))					\
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  * @inodes_count: number of inodes
235  * @blocks_count: number of blocks
236  * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot>
237  * @snapshot_kobj_unregister: completion state for kernel object
238  */
239 struct nilfs_root {
240 	__u64 cno;
241 	struct rb_node rb_node;
242 
243 	refcount_t count;
244 	struct the_nilfs *nilfs;
245 	struct inode *ifile;
246 
247 	atomic64_t inodes_count;
248 	atomic64_t blocks_count;
249 
250 	/* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */
251 	struct kobject snapshot_kobj;
252 	struct completion snapshot_kobj_unregister;
253 };
254 
255 /* Special checkpoint number */
256 #define NILFS_CPTREE_CURRENT_CNO	0
257 
258 /* Minimum interval of periodical update of superblocks (in seconds) */
259 #define NILFS_SB_FREQ		10
260 
nilfs_sb_need_update(struct the_nilfs * nilfs)261 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
262 {
263 	u64 t = ktime_get_real_seconds();
264 
265 	return t < nilfs->ns_sbwtime ||
266 		t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq;
267 }
268 
nilfs_sb_will_flip(struct the_nilfs * nilfs)269 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
270 {
271 	int flip_bits = nilfs->ns_sbwcount & 0x0FL;
272 
273 	return (flip_bits != 0x08 && flip_bits != 0x0F);
274 }
275 
276 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
277 struct the_nilfs *alloc_nilfs(struct super_block *sb);
278 void destroy_nilfs(struct the_nilfs *nilfs);
279 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data);
280 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
281 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs);
282 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs);
283 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
284 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
285 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
286 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
287 					     __u64 cno);
288 void nilfs_put_root(struct nilfs_root *root);
289 int nilfs_near_disk_full(struct the_nilfs *);
290 void nilfs_fall_back_super_block(struct the_nilfs *);
291 void nilfs_swap_super_block(struct the_nilfs *);
292 
293 
nilfs_get_root(struct nilfs_root * root)294 static inline void nilfs_get_root(struct nilfs_root *root)
295 {
296 	refcount_inc(&root->count);
297 }
298 
nilfs_valid_fs(struct the_nilfs * nilfs)299 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
300 {
301 	unsigned int valid_fs;
302 
303 	down_read(&nilfs->ns_sem);
304 	valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
305 	up_read(&nilfs->ns_sem);
306 	return valid_fs;
307 }
308 
309 static inline void
nilfs_get_segment_range(struct the_nilfs * nilfs,__u64 segnum,sector_t * seg_start,sector_t * seg_end)310 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
311 			sector_t *seg_start, sector_t *seg_end)
312 {
313 	*seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
314 	*seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
315 	if (segnum == 0)
316 		*seg_start = nilfs->ns_first_data_block;
317 }
318 
319 static inline sector_t
nilfs_get_segment_start_blocknr(struct the_nilfs * nilfs,__u64 segnum)320 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
321 {
322 	return (segnum == 0) ? nilfs->ns_first_data_block :
323 		(sector_t)nilfs->ns_blocks_per_segment * segnum;
324 }
325 
326 static inline __u64
nilfs_get_segnum_of_block(struct the_nilfs * nilfs,sector_t blocknr)327 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
328 {
329 	sector_t segnum = blocknr;
330 
331 	sector_div(segnum, nilfs->ns_blocks_per_segment);
332 	return segnum;
333 }
334 
335 static inline void
nilfs_terminate_segment(struct the_nilfs * nilfs,sector_t seg_start,sector_t seg_end)336 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
337 			sector_t seg_end)
338 {
339 	/* terminate the current full segment (used in case of I/O-error) */
340 	nilfs->ns_pseg_offset = seg_end - seg_start + 1;
341 }
342 
nilfs_shift_to_next_segment(struct the_nilfs * nilfs)343 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
344 {
345 	/* move forward with a full segment */
346 	nilfs->ns_segnum = nilfs->ns_nextnum;
347 	nilfs->ns_pseg_offset = 0;
348 	nilfs->ns_seg_seq++;
349 }
350 
nilfs_last_cno(struct the_nilfs * nilfs)351 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
352 {
353 	__u64 cno;
354 
355 	spin_lock(&nilfs->ns_last_segment_lock);
356 	cno = nilfs->ns_last_cno;
357 	spin_unlock(&nilfs->ns_last_segment_lock);
358 	return cno;
359 }
360 
nilfs_segment_is_active(struct the_nilfs * nilfs,__u64 n)361 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
362 {
363 	return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
364 }
365 
nilfs_flush_device(struct the_nilfs * nilfs)366 static inline int nilfs_flush_device(struct the_nilfs *nilfs)
367 {
368 	int err;
369 
370 	if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device)
371 		return 0;
372 
373 	nilfs->ns_flushed_device = 1;
374 	/*
375 	 * the store to ns_flushed_device must not be reordered after
376 	 * blkdev_issue_flush().
377 	 */
378 	smp_wmb();
379 
380 	err = blkdev_issue_flush(nilfs->ns_bdev);
381 	if (err != -EIO)
382 		err = 0;
383 	return err;
384 }
385 
386 #endif /* _THE_NILFS_H */
387