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 #include "sb.h" 35 36 /* the_nilfs struct */ 37 enum { 38 THE_NILFS_INIT = 0, /* Information from super_block is set */ 39 THE_NILFS_LOADED, /* Roll-back/roll-forward has done and 40 the latest checkpoint was loaded */ 41 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ 42 THE_NILFS_GC_RUNNING, /* gc process is running */ 43 THE_NILFS_SB_DIRTY, /* super block is dirty */ 44 }; 45 46 /** 47 * struct the_nilfs - struct to supervise multiple nilfs mount points 48 * @ns_flags: flags 49 * @ns_bdev: block device 50 * @ns_sem: semaphore for shared states 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_seg_seq: segment sequence counter 57 * @ns_segnum: index number of the latest full segment. 58 * @ns_nextnum: index number of the full segment index to be used next 59 * @ns_pseg_offset: offset of next partial segment in the current full segment 60 * @ns_cno: next checkpoint number 61 * @ns_ctime: write time of the last segment 62 * @ns_nongc_ctime: write time of the last segment not for cleaner operation 63 * @ns_ndirtyblks: Number of dirty data blocks 64 * @ns_last_segment_lock: lock protecting fields for the latest segment 65 * @ns_last_pseg: start block number of the latest segment 66 * @ns_last_seq: sequence value of the latest segment 67 * @ns_last_cno: checkpoint number of the latest segment 68 * @ns_prot_seq: least sequence number of segments which must not be reclaimed 69 * @ns_prev_seq: base sequence number used to decide if advance log cursor 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_cptree: rb-tree of all mounted checkpoints (nilfs_root) 75 * @ns_cptree_lock: lock protecting @ns_cptree 76 * @ns_gc_inodes: dummy inodes to keep live blocks 77 * @ns_blocksize_bits: bit length of block size 78 * @ns_blocksize: 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 87 */ 88 struct the_nilfs { 89 unsigned long ns_flags; 90 91 struct block_device *ns_bdev; 92 struct rw_semaphore ns_sem; 93 94 /* 95 * used for 96 * - loading the latest checkpoint exclusively. 97 * - allocating a new full segment. 98 * - protecting s_dirt in the super_block struct 99 * (see nilfs_write_super) and the following fields. 100 */ 101 struct buffer_head *ns_sbh[2]; 102 struct nilfs_super_block *ns_sbp[2]; 103 time_t ns_sbwtime; 104 unsigned ns_sbwcount; 105 unsigned ns_sbsize; 106 unsigned ns_mount_state; 107 108 /* 109 * Following fields are dedicated to a writable FS-instance. 110 * Except for the period seeking checkpoint, code outside the segment 111 * constructor must lock a segment semaphore while accessing these 112 * fields. 113 * The writable FS-instance is sole during a lifetime of the_nilfs. 114 */ 115 u64 ns_seg_seq; 116 __u64 ns_segnum; 117 __u64 ns_nextnum; 118 unsigned long ns_pseg_offset; 119 __u64 ns_cno; 120 time_t ns_ctime; 121 time_t ns_nongc_ctime; 122 atomic_t ns_ndirtyblks; 123 124 /* 125 * The following fields hold information on the latest partial segment 126 * written to disk with a super root. These fields are protected by 127 * ns_last_segment_lock. 128 */ 129 spinlock_t ns_last_segment_lock; 130 sector_t ns_last_pseg; 131 u64 ns_last_seq; 132 __u64 ns_last_cno; 133 u64 ns_prot_seq; 134 u64 ns_prev_seq; 135 136 struct rw_semaphore ns_segctor_sem; 137 138 /* 139 * Following fields are lock free except for the period before 140 * the_nilfs is initialized. 141 */ 142 struct inode *ns_dat; 143 struct inode *ns_cpfile; 144 struct inode *ns_sufile; 145 146 /* Checkpoint tree */ 147 struct rb_root ns_cptree; 148 spinlock_t ns_cptree_lock; 149 150 /* GC inode list */ 151 struct list_head ns_gc_inodes; 152 153 /* Disk layout information (static) */ 154 unsigned int ns_blocksize_bits; 155 unsigned int ns_blocksize; 156 unsigned long ns_nsegments; 157 unsigned long ns_blocks_per_segment; 158 unsigned long ns_r_segments_percentage; 159 unsigned long ns_nrsvsegs; 160 unsigned long ns_first_data_block; 161 int ns_inode_size; 162 int ns_first_ino; 163 u32 ns_crc_seed; 164 }; 165 166 #define THE_NILFS_FNS(bit, name) \ 167 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ 168 { \ 169 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 170 } \ 171 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ 172 { \ 173 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 174 } \ 175 static inline int nilfs_##name(struct the_nilfs *nilfs) \ 176 { \ 177 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 178 } 179 180 THE_NILFS_FNS(INIT, init) 181 THE_NILFS_FNS(LOADED, loaded) 182 THE_NILFS_FNS(DISCONTINUED, discontinued) 183 THE_NILFS_FNS(GC_RUNNING, gc_running) 184 THE_NILFS_FNS(SB_DIRTY, sb_dirty) 185 186 /** 187 * struct nilfs_root - nilfs root object 188 * @cno: checkpoint number 189 * @rb_node: red-black tree node 190 * @count: refcount of this structure 191 * @nilfs: nilfs object 192 * @ifile: inode file 193 * @root: root inode 194 * @inodes_count: number of inodes 195 * @blocks_count: number of blocks (Reserved) 196 */ 197 struct nilfs_root { 198 __u64 cno; 199 struct rb_node rb_node; 200 201 atomic_t count; 202 struct the_nilfs *nilfs; 203 struct inode *ifile; 204 205 atomic_t inodes_count; 206 atomic_t blocks_count; 207 }; 208 209 /* Special checkpoint number */ 210 #define NILFS_CPTREE_CURRENT_CNO 0 211 212 /* Minimum interval of periodical update of superblocks (in seconds) */ 213 #define NILFS_SB_FREQ 10 214 215 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) 216 { 217 u64 t = get_seconds(); 218 return t < nilfs->ns_sbwtime || t > nilfs->ns_sbwtime + NILFS_SB_FREQ; 219 } 220 221 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs) 222 { 223 int flip_bits = nilfs->ns_sbwcount & 0x0FL; 224 return (flip_bits != 0x08 && flip_bits != 0x0F); 225 } 226 227 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); 228 struct the_nilfs *alloc_nilfs(struct block_device *bdev); 229 void destroy_nilfs(struct the_nilfs *nilfs); 230 int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *); 231 int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *); 232 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t); 233 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); 234 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno); 235 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs, 236 __u64 cno); 237 void nilfs_put_root(struct nilfs_root *root); 238 struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64); 239 int nilfs_near_disk_full(struct the_nilfs *); 240 void nilfs_fall_back_super_block(struct the_nilfs *); 241 void nilfs_swap_super_block(struct the_nilfs *); 242 243 244 static inline void nilfs_get_root(struct nilfs_root *root) 245 { 246 atomic_inc(&root->count); 247 } 248 249 static inline int nilfs_valid_fs(struct the_nilfs *nilfs) 250 { 251 unsigned valid_fs; 252 253 down_read(&nilfs->ns_sem); 254 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); 255 up_read(&nilfs->ns_sem); 256 return valid_fs; 257 } 258 259 static inline void 260 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, 261 sector_t *seg_start, sector_t *seg_end) 262 { 263 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; 264 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; 265 if (segnum == 0) 266 *seg_start = nilfs->ns_first_data_block; 267 } 268 269 static inline sector_t 270 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) 271 { 272 return (segnum == 0) ? nilfs->ns_first_data_block : 273 (sector_t)nilfs->ns_blocks_per_segment * segnum; 274 } 275 276 static inline __u64 277 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) 278 { 279 sector_t segnum = blocknr; 280 281 sector_div(segnum, nilfs->ns_blocks_per_segment); 282 return segnum; 283 } 284 285 static inline void 286 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, 287 sector_t seg_end) 288 { 289 /* terminate the current full segment (used in case of I/O-error) */ 290 nilfs->ns_pseg_offset = seg_end - seg_start + 1; 291 } 292 293 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) 294 { 295 /* move forward with a full segment */ 296 nilfs->ns_segnum = nilfs->ns_nextnum; 297 nilfs->ns_pseg_offset = 0; 298 nilfs->ns_seg_seq++; 299 } 300 301 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) 302 { 303 __u64 cno; 304 305 spin_lock(&nilfs->ns_last_segment_lock); 306 cno = nilfs->ns_last_cno; 307 spin_unlock(&nilfs->ns_last_segment_lock); 308 return cno; 309 } 310 311 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) 312 { 313 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; 314 } 315 316 #endif /* _THE_NILFS_H */ 317