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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  	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  	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, GFP_KERNEL, NULL);
381  	if (err != -EIO)
382  		err = 0;
383  	return err;
384  }
385  
386  #endif /* _THE_NILFS_H */
387