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 struct nilfs_sysfs_dev_subgroups; 37 38 /* the_nilfs struct */ 39 enum { 40 THE_NILFS_INIT = 0, /* Information from super_block is set */ 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_snapshot_mount_mutex: mutex to protect snapshot mounts 52 * @ns_sbh: buffer heads of on-disk super blocks 53 * @ns_sbp: pointers to super block data 54 * @ns_sbwtime: previous write time of super block 55 * @ns_sbwcount: write count of super block 56 * @ns_sbsize: size of valid data in super block 57 * @ns_mount_state: file system state 58 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds) 59 * @ns_seg_seq: segment sequence counter 60 * @ns_segnum: index number of the latest full segment. 61 * @ns_nextnum: index number of the full segment index to be used next 62 * @ns_pseg_offset: offset of next partial segment in the current full segment 63 * @ns_cno: next checkpoint number 64 * @ns_ctime: write time of the last segment 65 * @ns_nongc_ctime: write time of the last segment not for cleaner operation 66 * @ns_ndirtyblks: Number of dirty data blocks 67 * @ns_last_segment_lock: lock protecting fields for the latest segment 68 * @ns_last_pseg: start block number of the latest segment 69 * @ns_last_seq: sequence value of the latest segment 70 * @ns_last_cno: checkpoint number of the latest segment 71 * @ns_prot_seq: least sequence number of segments which must not be reclaimed 72 * @ns_prev_seq: base sequence number used to decide if advance log cursor 73 * @ns_writer: log writer 74 * @ns_segctor_sem: semaphore protecting log write 75 * @ns_dat: DAT file inode 76 * @ns_cpfile: checkpoint file inode 77 * @ns_sufile: segusage file inode 78 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root) 79 * @ns_cptree_lock: lock protecting @ns_cptree 80 * @ns_dirty_files: list of dirty files 81 * @ns_inode_lock: lock protecting @ns_dirty_files 82 * @ns_gc_inodes: dummy inodes to keep live blocks 83 * @ns_next_generation: next generation number for inodes 84 * @ns_next_gen_lock: lock protecting @ns_next_generation 85 * @ns_mount_opt: mount options 86 * @ns_resuid: uid for reserved blocks 87 * @ns_resgid: gid for reserved blocks 88 * @ns_interval: checkpoint creation interval 89 * @ns_watermark: watermark for the number of dirty buffers 90 * @ns_blocksize_bits: bit length of block size 91 * @ns_blocksize: block size 92 * @ns_nsegments: number of segments in filesystem 93 * @ns_blocks_per_segment: number of blocks per segment 94 * @ns_r_segments_percentage: reserved segments percentage 95 * @ns_nrsvsegs: number of reserved segments 96 * @ns_first_data_block: block number of first data block 97 * @ns_inode_size: size of on-disk inode 98 * @ns_first_ino: first not-special inode number 99 * @ns_crc_seed: seed value of CRC32 calculation 100 * @ns_dev_kobj: /sys/fs/<nilfs>/<device> 101 * @ns_dev_kobj_unregister: completion state 102 * @ns_dev_subgroups: <device> subgroups pointer 103 */ 104 struct the_nilfs { 105 unsigned long ns_flags; 106 107 struct block_device *ns_bdev; 108 struct rw_semaphore ns_sem; 109 struct mutex ns_snapshot_mount_mutex; 110 111 /* 112 * used for 113 * - loading the latest checkpoint exclusively. 114 * - allocating a new full segment. 115 */ 116 struct buffer_head *ns_sbh[2]; 117 struct nilfs_super_block *ns_sbp[2]; 118 time_t ns_sbwtime; 119 unsigned ns_sbwcount; 120 unsigned ns_sbsize; 121 unsigned ns_mount_state; 122 unsigned ns_sb_update_freq; 123 124 /* 125 * Following fields are dedicated to a writable FS-instance. 126 * Except for the period seeking checkpoint, code outside the segment 127 * constructor must lock a segment semaphore while accessing these 128 * fields. 129 * The writable FS-instance is sole during a lifetime of the_nilfs. 130 */ 131 u64 ns_seg_seq; 132 __u64 ns_segnum; 133 __u64 ns_nextnum; 134 unsigned long ns_pseg_offset; 135 __u64 ns_cno; 136 time_t ns_ctime; 137 time_t ns_nongc_ctime; 138 atomic_t ns_ndirtyblks; 139 140 /* 141 * The following fields hold information on the latest partial segment 142 * written to disk with a super root. These fields are protected by 143 * ns_last_segment_lock. 144 */ 145 spinlock_t ns_last_segment_lock; 146 sector_t ns_last_pseg; 147 u64 ns_last_seq; 148 __u64 ns_last_cno; 149 u64 ns_prot_seq; 150 u64 ns_prev_seq; 151 152 struct nilfs_sc_info *ns_writer; 153 struct rw_semaphore ns_segctor_sem; 154 155 /* 156 * Following fields are lock free except for the period before 157 * the_nilfs is initialized. 158 */ 159 struct inode *ns_dat; 160 struct inode *ns_cpfile; 161 struct inode *ns_sufile; 162 163 /* Checkpoint tree */ 164 struct rb_root ns_cptree; 165 spinlock_t ns_cptree_lock; 166 167 /* Dirty inode list */ 168 struct list_head ns_dirty_files; 169 spinlock_t ns_inode_lock; 170 171 /* GC inode list */ 172 struct list_head ns_gc_inodes; 173 174 /* Inode allocator */ 175 u32 ns_next_generation; 176 spinlock_t ns_next_gen_lock; 177 178 /* Mount options */ 179 unsigned long ns_mount_opt; 180 181 uid_t ns_resuid; 182 gid_t ns_resgid; 183 unsigned long ns_interval; 184 unsigned long ns_watermark; 185 186 /* Disk layout information (static) */ 187 unsigned int ns_blocksize_bits; 188 unsigned int ns_blocksize; 189 unsigned long ns_nsegments; 190 unsigned long ns_blocks_per_segment; 191 unsigned long ns_r_segments_percentage; 192 unsigned long ns_nrsvsegs; 193 unsigned long ns_first_data_block; 194 int ns_inode_size; 195 int ns_first_ino; 196 u32 ns_crc_seed; 197 198 /* /sys/fs/<nilfs>/<device> */ 199 struct kobject ns_dev_kobj; 200 struct completion ns_dev_kobj_unregister; 201 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups; 202 }; 203 204 #define THE_NILFS_FNS(bit, name) \ 205 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ 206 { \ 207 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 208 } \ 209 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ 210 { \ 211 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 212 } \ 213 static inline int nilfs_##name(struct the_nilfs *nilfs) \ 214 { \ 215 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 216 } 217 218 THE_NILFS_FNS(INIT, init) 219 THE_NILFS_FNS(DISCONTINUED, discontinued) 220 THE_NILFS_FNS(GC_RUNNING, gc_running) 221 THE_NILFS_FNS(SB_DIRTY, sb_dirty) 222 223 /* 224 * Mount option operations 225 */ 226 #define nilfs_clear_opt(nilfs, opt) \ 227 do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0) 228 #define nilfs_set_opt(nilfs, opt) \ 229 do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0) 230 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt) 231 #define nilfs_write_opt(nilfs, mask, opt) \ 232 do { (nilfs)->ns_mount_opt = \ 233 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \ 234 NILFS_MOUNT_##opt); \ 235 } while (0) 236 237 /** 238 * struct nilfs_root - nilfs root object 239 * @cno: checkpoint number 240 * @rb_node: red-black tree node 241 * @count: refcount of this structure 242 * @nilfs: nilfs object 243 * @ifile: inode file 244 * @inodes_count: number of inodes 245 * @blocks_count: number of blocks 246 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> 247 * @snapshot_kobj_unregister: completion state for kernel object 248 */ 249 struct nilfs_root { 250 __u64 cno; 251 struct rb_node rb_node; 252 253 atomic_t count; 254 struct the_nilfs *nilfs; 255 struct inode *ifile; 256 257 atomic64_t inodes_count; 258 atomic64_t blocks_count; 259 260 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */ 261 struct kobject snapshot_kobj; 262 struct completion snapshot_kobj_unregister; 263 }; 264 265 /* Special checkpoint number */ 266 #define NILFS_CPTREE_CURRENT_CNO 0 267 268 /* Minimum interval of periodical update of superblocks (in seconds) */ 269 #define NILFS_SB_FREQ 10 270 271 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) 272 { 273 u64 t = get_seconds(); 274 return t < nilfs->ns_sbwtime || 275 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq; 276 } 277 278 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs) 279 { 280 int flip_bits = nilfs->ns_sbwcount & 0x0FL; 281 return (flip_bits != 0x08 && flip_bits != 0x0F); 282 } 283 284 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); 285 struct the_nilfs *alloc_nilfs(struct block_device *bdev); 286 void destroy_nilfs(struct the_nilfs *nilfs); 287 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data); 288 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb); 289 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs); 290 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs); 291 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t); 292 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); 293 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno); 294 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs, 295 __u64 cno); 296 void nilfs_put_root(struct nilfs_root *root); 297 int nilfs_near_disk_full(struct the_nilfs *); 298 void nilfs_fall_back_super_block(struct the_nilfs *); 299 void nilfs_swap_super_block(struct the_nilfs *); 300 301 302 static inline void nilfs_get_root(struct nilfs_root *root) 303 { 304 atomic_inc(&root->count); 305 } 306 307 static inline int nilfs_valid_fs(struct the_nilfs *nilfs) 308 { 309 unsigned valid_fs; 310 311 down_read(&nilfs->ns_sem); 312 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); 313 up_read(&nilfs->ns_sem); 314 return valid_fs; 315 } 316 317 static inline void 318 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, 319 sector_t *seg_start, sector_t *seg_end) 320 { 321 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; 322 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; 323 if (segnum == 0) 324 *seg_start = nilfs->ns_first_data_block; 325 } 326 327 static inline sector_t 328 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) 329 { 330 return (segnum == 0) ? nilfs->ns_first_data_block : 331 (sector_t)nilfs->ns_blocks_per_segment * segnum; 332 } 333 334 static inline __u64 335 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) 336 { 337 sector_t segnum = blocknr; 338 339 sector_div(segnum, nilfs->ns_blocks_per_segment); 340 return segnum; 341 } 342 343 static inline void 344 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, 345 sector_t seg_end) 346 { 347 /* terminate the current full segment (used in case of I/O-error) */ 348 nilfs->ns_pseg_offset = seg_end - seg_start + 1; 349 } 350 351 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) 352 { 353 /* move forward with a full segment */ 354 nilfs->ns_segnum = nilfs->ns_nextnum; 355 nilfs->ns_pseg_offset = 0; 356 nilfs->ns_seg_seq++; 357 } 358 359 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) 360 { 361 __u64 cno; 362 363 spin_lock(&nilfs->ns_last_segment_lock); 364 cno = nilfs->ns_last_cno; 365 spin_unlock(&nilfs->ns_last_segment_lock); 366 return cno; 367 } 368 369 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) 370 { 371 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; 372 } 373 374 #endif /* _THE_NILFS_H */ 375