2 * the_nilfs.h - the_nilfs shared structure.
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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.
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.
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
20 * Written by Ryusuke Konishi <ryusuke@osrg.net>
27 #include <linux/types.h>
28 #include <linux/buffer_head.h>
30 #include <linux/blkdev.h>
31 #include <linux/backing-dev.h>
34 /* the_nilfs struct */
36 THE_NILFS_INIT = 0, /* Information from super_block is set */
37 THE_NILFS_LOADED, /* Roll-back/roll-forward has done and
38 the latest checkpoint was loaded */
39 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
40 THE_NILFS_COND_NONGC_WRITE, /* Condition to wake up cleanerd */
44 * struct the_nilfs - struct to supervise multiple nilfs mount points
46 * @ns_count: reference count
47 * @ns_bdev: block device
48 * @ns_bdi: backing dev info
49 * @ns_writer: back pointer to writable nilfs_sb_info
50 * @ns_sem: semaphore for shared states
51 * @ns_writer_mutex: mutex protecting ns_writer attach/detach
52 * @ns_writer_refcount: number of referrers on ns_writer
53 * @ns_sbh: buffer head of the on-disk super block
54 * @ns_sbp: pointer to the super block data
55 * @ns_used_segments: list of full segments in volatile active state
56 * @ns_supers: list of nilfs super block structs
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_free_segments_count: counter of free segments
70 * @ns_segctor_sem: segment constructor semaphore
71 * @ns_dat: DAT file inode
72 * @ns_cpfile: checkpoint file inode
73 * @ns_sufile: segusage file inode
74 * @ns_gc_dat: shadow inode of the DAT file inode for GC
75 * @ns_gc_inodes: dummy inodes to keep live blocks
76 * @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks
77 * @ns_cleanerd_wq: wait queue for cleanerd
78 * @ns_blocksize_bits: bit length of block size
79 * @ns_nsegments: number of segments in filesystem
80 * @ns_blocks_per_segment: number of blocks per segment
81 * @ns_r_segments_percentage: reserved segments percentage
82 * @ns_nrsvsegs: number of reserved segments
83 * @ns_first_data_block: block number of first data block
84 * @ns_inode_size: size of on-disk inode
85 * @ns_first_ino: first not-special inode number
86 * @ns_crc_seed: seed value of CRC32 calculation
89 unsigned long ns_flags;
92 struct block_device *ns_bdev;
93 struct backing_dev_info *ns_bdi;
94 struct nilfs_sb_info *ns_writer;
95 struct rw_semaphore ns_sem;
96 struct mutex ns_writer_mutex;
97 atomic_t ns_writer_refcount;
101 * - loading the latest checkpoint exclusively.
102 * - allocating a new full segment.
103 * - protecting s_dirt in the super_block struct
104 * (see nilfs_write_super) and the following fields.
106 struct buffer_head *ns_sbh;
107 struct nilfs_super_block *ns_sbp;
108 struct list_head ns_used_segments;
109 unsigned ns_mount_state;
110 struct list_head ns_supers;
113 * Following fields are dedicated to a writable FS-instance.
114 * Except for the period seeking checkpoint, code outside the segment
115 * constructor must lock a segment semaphore while accessing these
117 * The writable FS-instance is sole during a lifetime of the_nilfs.
122 unsigned long ns_pseg_offset;
125 time_t ns_nongc_ctime;
126 atomic_t ns_ndirtyblks;
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.
133 spinlock_t ns_last_segment_lock;
134 sector_t ns_last_pseg;
137 unsigned long ns_free_segments_count;
139 struct rw_semaphore ns_segctor_sem;
142 * Following fields are lock free except for the period before
143 * the_nilfs is initialized.
145 struct inode *ns_dat;
146 struct inode *ns_cpfile;
147 struct inode *ns_sufile;
148 struct inode *ns_gc_dat;
150 /* GC inode list and hash table head */
151 struct list_head ns_gc_inodes;
152 struct hlist_head *ns_gc_inodes_h;
155 wait_queue_head_t ns_cleanerd_wq;
157 /* Disk layout information (static) */
158 unsigned int ns_blocksize_bits;
159 unsigned long ns_nsegments;
160 unsigned long ns_blocks_per_segment;
161 unsigned long ns_r_segments_percentage;
162 unsigned long ns_nrsvsegs;
163 unsigned long ns_first_data_block;
169 #define NILFS_GCINODE_HASH_BITS 8
170 #define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS)
172 #define THE_NILFS_FNS(bit, name) \
173 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
175 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
177 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
179 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
181 static inline int nilfs_##name(struct the_nilfs *nilfs) \
183 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
186 THE_NILFS_FNS(INIT, init)
187 THE_NILFS_FNS(LOADED, loaded)
188 THE_NILFS_FNS(DISCONTINUED, discontinued)
189 THE_NILFS_FNS(COND_NONGC_WRITE, cond_nongc_write)
191 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
192 struct the_nilfs *alloc_nilfs(struct block_device *);
193 void put_nilfs(struct the_nilfs *);
194 int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
195 int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
196 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
197 void nilfs_dispose_used_segments(struct the_nilfs *);
198 int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int);
199 int nilfs_near_disk_full(struct the_nilfs *);
202 static inline void get_nilfs(struct the_nilfs *nilfs)
204 /* Caller must have at least one reference of the_nilfs. */
205 atomic_inc(&nilfs->ns_count);
208 static inline struct nilfs_sb_info *nilfs_get_writer(struct the_nilfs *nilfs)
210 if (atomic_inc_and_test(&nilfs->ns_writer_refcount))
211 mutex_lock(&nilfs->ns_writer_mutex);
212 return nilfs->ns_writer;
215 static inline void nilfs_put_writer(struct the_nilfs *nilfs)
217 if (atomic_add_negative(-1, &nilfs->ns_writer_refcount))
218 mutex_unlock(&nilfs->ns_writer_mutex);
222 nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
224 mutex_lock(&nilfs->ns_writer_mutex);
225 nilfs->ns_writer = sbi;
226 mutex_unlock(&nilfs->ns_writer_mutex);
230 nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
232 mutex_lock(&nilfs->ns_writer_mutex);
233 if (sbi == nilfs->ns_writer)
234 nilfs->ns_writer = NULL;
235 mutex_unlock(&nilfs->ns_writer_mutex);
239 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
240 sector_t *seg_start, sector_t *seg_end)
242 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
243 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
245 *seg_start = nilfs->ns_first_data_block;
248 static inline sector_t
249 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
251 return (segnum == 0) ? nilfs->ns_first_data_block :
252 (sector_t)nilfs->ns_blocks_per_segment * segnum;
256 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
258 sector_t segnum = blocknr;
260 sector_div(segnum, nilfs->ns_blocks_per_segment);
265 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
268 /* terminate the current full segment (used in case of I/O-error) */
269 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
272 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
274 /* move forward with a full segment */
275 nilfs->ns_segnum = nilfs->ns_nextnum;
276 nilfs->ns_pseg_offset = 0;
280 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
284 spin_lock(&nilfs->ns_last_segment_lock);
285 cno = nilfs->ns_last_cno;
286 spin_unlock(&nilfs->ns_last_segment_lock);
290 #endif /* _THE_NILFS_H */