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