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 * Written by Ryusuke Konishi. 17 * 18 */ 19 20 #ifndef _THE_NILFS_H 21 #define _THE_NILFS_H 22 23 #include <linux/types.h> 24 #include <linux/buffer_head.h> 25 #include <linux/rbtree.h> 26 #include <linux/fs.h> 27 #include <linux/blkdev.h> 28 #include <linux/backing-dev.h> 29 #include <linux/slab.h> 30 31 struct nilfs_sc_info; 32 struct nilfs_sysfs_dev_subgroups; 33 34 /* the_nilfs struct */ 35 enum { 36 THE_NILFS_INIT = 0, /* Information from super_block is set */ 37 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ 38 THE_NILFS_GC_RUNNING, /* gc process is running */ 39 THE_NILFS_SB_DIRTY, /* super block is dirty */ 40 }; 41 42 /** 43 * struct the_nilfs - struct to supervise multiple nilfs mount points 44 * @ns_flags: flags 45 * @ns_flushed_device: flag indicating if all volatile data was flushed 46 * @ns_sb: back pointer to super block instance 47 * @ns_bdev: block device 48 * @ns_sem: semaphore for shared states 49 * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts 50 * @ns_sbh: buffer heads of on-disk super blocks 51 * @ns_sbp: pointers to super block data 52 * @ns_sbwtime: previous write time of super block 53 * @ns_sbwcount: write count of super block 54 * @ns_sbsize: size of valid data in super block 55 * @ns_mount_state: file system state 56 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds) 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 * @ns_dev_kobj: /sys/fs/<nilfs>/<device> 99 * @ns_dev_kobj_unregister: completion state 100 * @ns_dev_subgroups: <device> subgroups pointer 101 */ 102 struct the_nilfs { 103 unsigned long ns_flags; 104 int ns_flushed_device; 105 106 struct super_block *ns_sb; 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 int ns_sbwcount; 120 unsigned int ns_sbsize; 121 unsigned int ns_mount_state; 122 unsigned int ns_sb_update_freq; 123 124 /* 125 * The following fields are updated by a writable FS-instance. 126 * These fields are protected by ns_segctor_sem outside load_nilfs(). 127 */ 128 u64 ns_seg_seq; 129 __u64 ns_segnum; 130 __u64 ns_nextnum; 131 unsigned long ns_pseg_offset; 132 __u64 ns_cno; 133 time_t ns_ctime; 134 time_t ns_nongc_ctime; 135 atomic_t ns_ndirtyblks; 136 137 /* 138 * The following fields hold information on the latest partial segment 139 * written to disk with a super root. These fields are protected by 140 * ns_last_segment_lock. 141 */ 142 spinlock_t ns_last_segment_lock; 143 sector_t ns_last_pseg; 144 u64 ns_last_seq; 145 __u64 ns_last_cno; 146 u64 ns_prot_seq; 147 u64 ns_prev_seq; 148 149 struct nilfs_sc_info *ns_writer; 150 struct rw_semaphore ns_segctor_sem; 151 152 /* 153 * Following fields are lock free except for the period before 154 * the_nilfs is initialized. 155 */ 156 struct inode *ns_dat; 157 struct inode *ns_cpfile; 158 struct inode *ns_sufile; 159 160 /* Checkpoint tree */ 161 struct rb_root ns_cptree; 162 spinlock_t ns_cptree_lock; 163 164 /* Dirty inode list */ 165 struct list_head ns_dirty_files; 166 spinlock_t ns_inode_lock; 167 168 /* GC inode list */ 169 struct list_head ns_gc_inodes; 170 171 /* Inode allocator */ 172 u32 ns_next_generation; 173 spinlock_t ns_next_gen_lock; 174 175 /* Mount options */ 176 unsigned long ns_mount_opt; 177 178 uid_t ns_resuid; 179 gid_t ns_resgid; 180 unsigned long ns_interval; 181 unsigned long ns_watermark; 182 183 /* Disk layout information (static) */ 184 unsigned int ns_blocksize_bits; 185 unsigned int ns_blocksize; 186 unsigned long ns_nsegments; 187 unsigned long ns_blocks_per_segment; 188 unsigned long ns_r_segments_percentage; 189 unsigned long ns_nrsvsegs; 190 unsigned long ns_first_data_block; 191 int ns_inode_size; 192 int ns_first_ino; 193 u32 ns_crc_seed; 194 195 /* /sys/fs/<nilfs>/<device> */ 196 struct kobject ns_dev_kobj; 197 struct completion ns_dev_kobj_unregister; 198 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups; 199 }; 200 201 #define THE_NILFS_FNS(bit, name) \ 202 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ 203 { \ 204 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 205 } \ 206 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ 207 { \ 208 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 209 } \ 210 static inline int nilfs_##name(struct the_nilfs *nilfs) \ 211 { \ 212 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 213 } 214 215 THE_NILFS_FNS(INIT, init) 216 THE_NILFS_FNS(DISCONTINUED, discontinued) 217 THE_NILFS_FNS(GC_RUNNING, gc_running) 218 THE_NILFS_FNS(SB_DIRTY, sb_dirty) 219 220 /* 221 * Mount option operations 222 */ 223 #define nilfs_clear_opt(nilfs, opt) \ 224 ((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt) 225 #define nilfs_set_opt(nilfs, opt) \ 226 ((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt) 227 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt) 228 #define nilfs_write_opt(nilfs, mask, opt) \ 229 ((nilfs)->ns_mount_opt = \ 230 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \ 231 NILFS_MOUNT_##opt)) \ 232 233 /** 234 * struct nilfs_root - nilfs root object 235 * @cno: checkpoint number 236 * @rb_node: red-black tree node 237 * @count: refcount of this structure 238 * @nilfs: nilfs object 239 * @ifile: inode file 240 * @inodes_count: number of inodes 241 * @blocks_count: number of blocks 242 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> 243 * @snapshot_kobj_unregister: completion state for kernel object 244 */ 245 struct nilfs_root { 246 __u64 cno; 247 struct rb_node rb_node; 248 249 atomic_t count; 250 struct the_nilfs *nilfs; 251 struct inode *ifile; 252 253 atomic64_t inodes_count; 254 atomic64_t blocks_count; 255 256 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */ 257 struct kobject snapshot_kobj; 258 struct completion snapshot_kobj_unregister; 259 }; 260 261 /* Special checkpoint number */ 262 #define NILFS_CPTREE_CURRENT_CNO 0 263 264 /* Minimum interval of periodical update of superblocks (in seconds) */ 265 #define NILFS_SB_FREQ 10 266 267 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) 268 { 269 u64 t = get_seconds(); 270 271 return t < nilfs->ns_sbwtime || 272 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq; 273 } 274 275 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs) 276 { 277 int flip_bits = nilfs->ns_sbwcount & 0x0FL; 278 279 return (flip_bits != 0x08 && flip_bits != 0x0F); 280 } 281 282 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); 283 struct the_nilfs *alloc_nilfs(struct super_block *sb); 284 void destroy_nilfs(struct the_nilfs *nilfs); 285 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data); 286 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb); 287 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs); 288 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs); 289 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t); 290 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); 291 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno); 292 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs, 293 __u64 cno); 294 void nilfs_put_root(struct nilfs_root *root); 295 int nilfs_near_disk_full(struct the_nilfs *); 296 void nilfs_fall_back_super_block(struct the_nilfs *); 297 void nilfs_swap_super_block(struct the_nilfs *); 298 299 300 static inline void nilfs_get_root(struct nilfs_root *root) 301 { 302 atomic_inc(&root->count); 303 } 304 305 static inline int nilfs_valid_fs(struct the_nilfs *nilfs) 306 { 307 unsigned int valid_fs; 308 309 down_read(&nilfs->ns_sem); 310 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); 311 up_read(&nilfs->ns_sem); 312 return valid_fs; 313 } 314 315 static inline void 316 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, 317 sector_t *seg_start, sector_t *seg_end) 318 { 319 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; 320 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; 321 if (segnum == 0) 322 *seg_start = nilfs->ns_first_data_block; 323 } 324 325 static inline sector_t 326 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) 327 { 328 return (segnum == 0) ? nilfs->ns_first_data_block : 329 (sector_t)nilfs->ns_blocks_per_segment * segnum; 330 } 331 332 static inline __u64 333 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) 334 { 335 sector_t segnum = blocknr; 336 337 sector_div(segnum, nilfs->ns_blocks_per_segment); 338 return segnum; 339 } 340 341 static inline void 342 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, 343 sector_t seg_end) 344 { 345 /* terminate the current full segment (used in case of I/O-error) */ 346 nilfs->ns_pseg_offset = seg_end - seg_start + 1; 347 } 348 349 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) 350 { 351 /* move forward with a full segment */ 352 nilfs->ns_segnum = nilfs->ns_nextnum; 353 nilfs->ns_pseg_offset = 0; 354 nilfs->ns_seg_seq++; 355 } 356 357 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) 358 { 359 __u64 cno; 360 361 spin_lock(&nilfs->ns_last_segment_lock); 362 cno = nilfs->ns_last_cno; 363 spin_unlock(&nilfs->ns_last_segment_lock); 364 return cno; 365 } 366 367 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) 368 { 369 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; 370 } 371 372 static inline int nilfs_flush_device(struct the_nilfs *nilfs) 373 { 374 int err; 375 376 if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device) 377 return 0; 378 379 nilfs->ns_flushed_device = 1; 380 /* 381 * the store to ns_flushed_device must not be reordered after 382 * blkdev_issue_flush(). 383 */ 384 smp_wmb(); 385 386 err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL, NULL); 387 if (err != -EIO) 388 err = 0; 389 return err; 390 } 391 392 #endif /* _THE_NILFS_H */ 393