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>
29 #include <linux/rbtree.h>
31 #include <linux/blkdev.h>
32 #include <linux/backing-dev.h>
33 #include <linux/slab.h>
36 /* the_nilfs struct */
38 THE_NILFS_INIT = 0, /* Information from super_block is set */
39 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
40 THE_NILFS_GC_RUNNING, /* gc process is running */
41 THE_NILFS_SB_DIRTY, /* super block is dirty */
45 * struct the_nilfs - struct to supervise multiple nilfs mount points
47 * @ns_bdev: block device
48 * @ns_sem: semaphore for shared states
49 * @ns_sbh: buffer heads of on-disk super blocks
50 * @ns_sbp: pointers to super block data
51 * @ns_sbwtime: previous write time of super block
52 * @ns_sbwcount: write count of super block
53 * @ns_sbsize: size of valid data in super block
54 * @ns_seg_seq: segment sequence counter
55 * @ns_segnum: index number of the latest full segment.
56 * @ns_nextnum: index number of the full segment index to be used next
57 * @ns_pseg_offset: offset of next partial segment in the current full segment
58 * @ns_cno: next checkpoint number
59 * @ns_ctime: write time of the last segment
60 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
61 * @ns_ndirtyblks: Number of dirty data blocks
62 * @ns_last_segment_lock: lock protecting fields for the latest segment
63 * @ns_last_pseg: start block number of the latest segment
64 * @ns_last_seq: sequence value of the latest segment
65 * @ns_last_cno: checkpoint number of the latest segment
66 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
67 * @ns_prev_seq: base sequence number used to decide if advance log cursor
68 * @ns_segctor_sem: segment constructor semaphore
69 * @ns_dat: DAT file inode
70 * @ns_cpfile: checkpoint file inode
71 * @ns_sufile: segusage file inode
72 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
73 * @ns_cptree_lock: lock protecting @ns_cptree
74 * @ns_dirty_files: list of dirty files
75 * @ns_inode_lock: lock protecting @ns_dirty_files
76 * @ns_gc_inodes: dummy inodes to keep live blocks
77 * @ns_mount_opt: mount options
78 * @ns_resuid: uid for reserved blocks
79 * @ns_resgid: gid for reserved blocks
80 * @ns_interval: checkpoint creation interval
81 * @ns_watermark: watermark for the number of dirty buffers
82 * @ns_blocksize_bits: bit length of block size
83 * @ns_blocksize: block size
84 * @ns_nsegments: number of segments in filesystem
85 * @ns_blocks_per_segment: number of blocks per segment
86 * @ns_r_segments_percentage: reserved segments percentage
87 * @ns_nrsvsegs: number of reserved segments
88 * @ns_first_data_block: block number of first data block
89 * @ns_inode_size: size of on-disk inode
90 * @ns_first_ino: first not-special inode number
91 * @ns_crc_seed: seed value of CRC32 calculation
94 unsigned long ns_flags;
96 struct block_device *ns_bdev;
97 struct rw_semaphore ns_sem;
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[2];
107 struct nilfs_super_block *ns_sbp[2];
109 unsigned ns_sbwcount;
111 unsigned ns_mount_state;
114 * Following fields are dedicated to a writable FS-instance.
115 * Except for the period seeking checkpoint, code outside the segment
116 * constructor must lock a segment semaphore while accessing these
118 * The writable FS-instance is sole during a lifetime of the_nilfs.
123 unsigned long ns_pseg_offset;
126 time_t ns_nongc_ctime;
127 atomic_t ns_ndirtyblks;
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.
134 spinlock_t ns_last_segment_lock;
135 sector_t ns_last_pseg;
141 struct rw_semaphore ns_segctor_sem;
144 * Following fields are lock free except for the period before
145 * the_nilfs is initialized.
147 struct inode *ns_dat;
148 struct inode *ns_cpfile;
149 struct inode *ns_sufile;
151 /* Checkpoint tree */
152 struct rb_root ns_cptree;
153 spinlock_t ns_cptree_lock;
155 /* Dirty inode list */
156 struct list_head ns_dirty_files;
157 spinlock_t ns_inode_lock;
160 struct list_head ns_gc_inodes;
163 unsigned long ns_mount_opt;
167 unsigned long ns_interval;
168 unsigned long ns_watermark;
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;
183 #define THE_NILFS_FNS(bit, name) \
184 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
186 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
188 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
190 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
192 static inline int nilfs_##name(struct the_nilfs *nilfs) \
194 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
197 THE_NILFS_FNS(INIT, init)
198 THE_NILFS_FNS(DISCONTINUED, discontinued)
199 THE_NILFS_FNS(GC_RUNNING, gc_running)
200 THE_NILFS_FNS(SB_DIRTY, sb_dirty)
203 * Mount option operations
205 #define nilfs_clear_opt(nilfs, opt) \
206 do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)
207 #define nilfs_set_opt(nilfs, opt) \
208 do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0)
209 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
210 #define nilfs_write_opt(nilfs, mask, opt) \
211 do { (nilfs)->ns_mount_opt = \
212 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \
213 NILFS_MOUNT_##opt); \
217 * struct nilfs_root - nilfs root object
218 * @cno: checkpoint number
219 * @rb_node: red-black tree node
220 * @count: refcount of this structure
221 * @nilfs: nilfs object
224 * @inodes_count: number of inodes
225 * @blocks_count: number of blocks (Reserved)
229 struct rb_node rb_node;
232 struct the_nilfs *nilfs;
235 atomic_t inodes_count;
236 atomic_t blocks_count;
239 /* Special checkpoint number */
240 #define NILFS_CPTREE_CURRENT_CNO 0
242 /* Minimum interval of periodical update of superblocks (in seconds) */
243 #define NILFS_SB_FREQ 10
245 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
247 u64 t = get_seconds();
248 return t < nilfs->ns_sbwtime || t > nilfs->ns_sbwtime + NILFS_SB_FREQ;
251 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
253 int flip_bits = nilfs->ns_sbwcount & 0x0FL;
254 return (flip_bits != 0x08 && flip_bits != 0x0F);
257 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
258 struct the_nilfs *alloc_nilfs(struct block_device *bdev);
259 void destroy_nilfs(struct the_nilfs *nilfs);
260 int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
261 int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
262 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
263 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
264 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
265 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
267 void nilfs_put_root(struct nilfs_root *root);
268 struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64);
269 int nilfs_near_disk_full(struct the_nilfs *);
270 void nilfs_fall_back_super_block(struct the_nilfs *);
271 void nilfs_swap_super_block(struct the_nilfs *);
274 static inline void nilfs_get_root(struct nilfs_root *root)
276 atomic_inc(&root->count);
279 static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
283 down_read(&nilfs->ns_sem);
284 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
285 up_read(&nilfs->ns_sem);
290 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
291 sector_t *seg_start, sector_t *seg_end)
293 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
294 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
296 *seg_start = nilfs->ns_first_data_block;
299 static inline sector_t
300 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
302 return (segnum == 0) ? nilfs->ns_first_data_block :
303 (sector_t)nilfs->ns_blocks_per_segment * segnum;
307 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
309 sector_t segnum = blocknr;
311 sector_div(segnum, nilfs->ns_blocks_per_segment);
316 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
319 /* terminate the current full segment (used in case of I/O-error) */
320 nilfs->ns_pseg_offset = seg_end - seg_start + 1;
323 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
325 /* move forward with a full segment */
326 nilfs->ns_segnum = nilfs->ns_nextnum;
327 nilfs->ns_pseg_offset = 0;
331 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
335 spin_lock(&nilfs->ns_last_segment_lock);
336 cno = nilfs->ns_last_cno;
337 spin_unlock(&nilfs->ns_last_segment_lock);
341 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
343 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
346 #endif /* _THE_NILFS_H */