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TOMOYO Linux Cross Reference
Linux/fs/nilfs2/the_nilfs.h

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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 };
 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 
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 
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 
292 static inline void nilfs_get_root(struct nilfs_root *root)
293 {
294         refcount_inc(&root->count);
295 }
296 
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
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
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
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
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 
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 
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 
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 
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 

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