xref: /linux/fs/nilfs2/the_nilfs.h (revision 3ea5eb68b9d624935108b5e696859304edfac202)
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 
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 
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 
284 static inline void nilfs_get_root(struct nilfs_root *root)
285 {
286 	refcount_inc(&root->count);
287 }
288 
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
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
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
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
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 
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 
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 
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 
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