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

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  1 /*
  2  * the_nilfs.h - the_nilfs shared structure.
  3  *
  4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License as published by
  8  * the Free Software Foundation; either version 2 of the License, or
  9  * (at your option) any later version.
 10  *
 11  * This program is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  * GNU General Public License for more details.
 15  *
 16  * You should have received a copy of the GNU General Public License
 17  * along with this program; if not, write to the Free Software
 18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 19  *
 20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
 21  *
 22  */
 23 
 24 #ifndef _THE_NILFS_H
 25 #define _THE_NILFS_H
 26 
 27 #include <linux/types.h>
 28 #include <linux/buffer_head.h>
 29 #include <linux/rbtree.h>
 30 #include <linux/fs.h>
 31 #include <linux/blkdev.h>
 32 #include <linux/backing-dev.h>
 33 #include <linux/slab.h>
 34 
 35 struct nilfs_sc_info;
 36 
 37 /* the_nilfs struct */
 38 enum {
 39         THE_NILFS_INIT = 0,     /* Information from super_block is set */
 40         THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
 41         THE_NILFS_GC_RUNNING,   /* gc process is running */
 42         THE_NILFS_SB_DIRTY,     /* super block is dirty */
 43 };
 44 
 45 /**
 46  * struct the_nilfs - struct to supervise multiple nilfs mount points
 47  * @ns_flags: flags
 48  * @ns_bdev: block device
 49  * @ns_sem: semaphore for shared states
 50  * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts
 51  * @ns_sbh: buffer heads of on-disk super blocks
 52  * @ns_sbp: pointers to super block data
 53  * @ns_sbwtime: previous write time of super block
 54  * @ns_sbwcount: write count of super block
 55  * @ns_sbsize: size of valid data in super block
 56  * @ns_mount_state: file system state
 57  * @ns_seg_seq: segment sequence counter
 58  * @ns_segnum: index number of the latest full segment.
 59  * @ns_nextnum: index number of the full segment index to be used next
 60  * @ns_pseg_offset: offset of next partial segment in the current full segment
 61  * @ns_cno: next checkpoint number
 62  * @ns_ctime: write time of the last segment
 63  * @ns_nongc_ctime: write time of the last segment not for cleaner operation
 64  * @ns_ndirtyblks: Number of dirty data blocks
 65  * @ns_last_segment_lock: lock protecting fields for the latest segment
 66  * @ns_last_pseg: start block number of the latest segment
 67  * @ns_last_seq: sequence value of the latest segment
 68  * @ns_last_cno: checkpoint number of the latest segment
 69  * @ns_prot_seq: least sequence number of segments which must not be reclaimed
 70  * @ns_prev_seq: base sequence number used to decide if advance log cursor
 71  * @ns_writer: log writer
 72  * @ns_segctor_sem: semaphore protecting log write
 73  * @ns_dat: DAT file inode
 74  * @ns_cpfile: checkpoint file inode
 75  * @ns_sufile: segusage file inode
 76  * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
 77  * @ns_cptree_lock: lock protecting @ns_cptree
 78  * @ns_dirty_files: list of dirty files
 79  * @ns_inode_lock: lock protecting @ns_dirty_files
 80  * @ns_gc_inodes: dummy inodes to keep live blocks
 81  * @ns_next_generation: next generation number for inodes
 82  * @ns_next_gen_lock: lock protecting @ns_next_generation
 83  * @ns_mount_opt: mount options
 84  * @ns_resuid: uid for reserved blocks
 85  * @ns_resgid: gid for reserved blocks
 86  * @ns_interval: checkpoint creation interval
 87  * @ns_watermark: watermark for the number of dirty buffers
 88  * @ns_blocksize_bits: bit length of block size
 89  * @ns_blocksize: block size
 90  * @ns_nsegments: number of segments in filesystem
 91  * @ns_blocks_per_segment: number of blocks per segment
 92  * @ns_r_segments_percentage: reserved segments percentage
 93  * @ns_nrsvsegs: number of reserved segments
 94  * @ns_first_data_block: block number of first data block
 95  * @ns_inode_size: size of on-disk inode
 96  * @ns_first_ino: first not-special inode number
 97  * @ns_crc_seed: seed value of CRC32 calculation
 98  */
 99 struct the_nilfs {
100         unsigned long           ns_flags;
101 
102         struct block_device    *ns_bdev;
103         struct rw_semaphore     ns_sem;
104         struct mutex            ns_snapshot_mount_mutex;
105 
106         /*
107          * used for
108          * - loading the latest checkpoint exclusively.
109          * - allocating a new full segment.
110          */
111         struct buffer_head     *ns_sbh[2];
112         struct nilfs_super_block *ns_sbp[2];
113         time_t                  ns_sbwtime;
114         unsigned                ns_sbwcount;
115         unsigned                ns_sbsize;
116         unsigned                ns_mount_state;
117 
118         /*
119          * Following fields are dedicated to a writable FS-instance.
120          * Except for the period seeking checkpoint, code outside the segment
121          * constructor must lock a segment semaphore while accessing these
122          * fields.
123          * The writable FS-instance is sole during a lifetime of the_nilfs.
124          */
125         u64                     ns_seg_seq;
126         __u64                   ns_segnum;
127         __u64                   ns_nextnum;
128         unsigned long           ns_pseg_offset;
129         __u64                   ns_cno;
130         time_t                  ns_ctime;
131         time_t                  ns_nongc_ctime;
132         atomic_t                ns_ndirtyblks;
133 
134         /*
135          * The following fields hold information on the latest partial segment
136          * written to disk with a super root.  These fields are protected by
137          * ns_last_segment_lock.
138          */
139         spinlock_t              ns_last_segment_lock;
140         sector_t                ns_last_pseg;
141         u64                     ns_last_seq;
142         __u64                   ns_last_cno;
143         u64                     ns_prot_seq;
144         u64                     ns_prev_seq;
145 
146         struct nilfs_sc_info   *ns_writer;
147         struct rw_semaphore     ns_segctor_sem;
148 
149         /*
150          * Following fields are lock free except for the period before
151          * the_nilfs is initialized.
152          */
153         struct inode           *ns_dat;
154         struct inode           *ns_cpfile;
155         struct inode           *ns_sufile;
156 
157         /* Checkpoint tree */
158         struct rb_root          ns_cptree;
159         spinlock_t              ns_cptree_lock;
160 
161         /* Dirty inode list */
162         struct list_head        ns_dirty_files;
163         spinlock_t              ns_inode_lock;
164 
165         /* GC inode list */
166         struct list_head        ns_gc_inodes;
167 
168         /* Inode allocator */
169         u32                     ns_next_generation;
170         spinlock_t              ns_next_gen_lock;
171 
172         /* Mount options */
173         unsigned long           ns_mount_opt;
174 
175         uid_t                   ns_resuid;
176         gid_t                   ns_resgid;
177         unsigned long           ns_interval;
178         unsigned long           ns_watermark;
179 
180         /* Disk layout information (static) */
181         unsigned int            ns_blocksize_bits;
182         unsigned int            ns_blocksize;
183         unsigned long           ns_nsegments;
184         unsigned long           ns_blocks_per_segment;
185         unsigned long           ns_r_segments_percentage;
186         unsigned long           ns_nrsvsegs;
187         unsigned long           ns_first_data_block;
188         int                     ns_inode_size;
189         int                     ns_first_ino;
190         u32                     ns_crc_seed;
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         do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)
217 #define nilfs_set_opt(nilfs, opt)  \
218         do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0)
219 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
220 #define nilfs_write_opt(nilfs, mask, opt)                               \
221         do { (nilfs)->ns_mount_opt =                                    \
222                 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) |        \
223                  NILFS_MOUNT_##opt);                                    \
224         } while (0)
225 
226 /**
227  * struct nilfs_root - nilfs root object
228  * @cno: checkpoint number
229  * @rb_node: red-black tree node
230  * @count: refcount of this structure
231  * @nilfs: nilfs object
232  * @ifile: inode file
233  * @inodes_count: number of inodes
234  * @blocks_count: number of blocks
235  */
236 struct nilfs_root {
237         __u64 cno;
238         struct rb_node rb_node;
239 
240         atomic_t count;
241         struct the_nilfs *nilfs;
242         struct inode *ifile;
243 
244         atomic64_t inodes_count;
245         atomic64_t blocks_count;
246 };
247 
248 /* Special checkpoint number */
249 #define NILFS_CPTREE_CURRENT_CNO        0
250 
251 /* Minimum interval of periodical update of superblocks (in seconds) */
252 #define NILFS_SB_FREQ           10
253 
254 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
255 {
256         u64 t = get_seconds();
257         return t < nilfs->ns_sbwtime || t > nilfs->ns_sbwtime + NILFS_SB_FREQ;
258 }
259 
260 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
261 {
262         int flip_bits = nilfs->ns_sbwcount & 0x0FL;
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 block_device *bdev);
268 void destroy_nilfs(struct the_nilfs *nilfs);
269 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data);
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         atomic_inc(&root->count);
287 }
288 
289 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
290 {
291         unsigned 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 #endif /* _THE_NILFS_H */
357 

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