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_bdev: block device 47 * @ns_sem: semaphore for shared states 48 * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts 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_mount_state: file system state 55 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds) 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_writer: log writer 71 * @ns_segctor_sem: semaphore protecting log write 72 * @ns_dat: DAT file inode 73 * @ns_cpfile: checkpoint file inode 74 * @ns_sufile: segusage file inode 75 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root) 76 * @ns_cptree_lock: lock protecting @ns_cptree 77 * @ns_dirty_files: list of dirty files 78 * @ns_inode_lock: lock protecting @ns_dirty_files 79 * @ns_gc_inodes: dummy inodes to keep live blocks 80 * @ns_next_generation: next generation number for inodes 81 * @ns_next_gen_lock: lock protecting @ns_next_generation 82 * @ns_mount_opt: mount options 83 * @ns_resuid: uid for reserved blocks 84 * @ns_resgid: gid for reserved blocks 85 * @ns_interval: checkpoint creation interval 86 * @ns_watermark: watermark for the number of dirty buffers 87 * @ns_blocksize_bits: bit length of block size 88 * @ns_blocksize: block size 89 * @ns_nsegments: number of segments in filesystem 90 * @ns_blocks_per_segment: number of blocks per segment 91 * @ns_r_segments_percentage: reserved segments percentage 92 * @ns_nrsvsegs: number of reserved segments 93 * @ns_first_data_block: block number of first data block 94 * @ns_inode_size: size of on-disk inode 95 * @ns_first_ino: first not-special inode number 96 * @ns_crc_seed: seed value of CRC32 calculation 97 * @ns_dev_kobj: /sys/fs/<nilfs>/<device> 98 * @ns_dev_kobj_unregister: completion state 99 * @ns_dev_subgroups: <device> subgroups pointer 100 */ 101 struct the_nilfs { 102 unsigned long ns_flags; 103 int ns_flushed_device; 104 105 struct block_device *ns_bdev; 106 struct rw_semaphore ns_sem; 107 struct mutex ns_snapshot_mount_mutex; 108 109 /* 110 * used for 111 * - loading the latest checkpoint exclusively. 112 * - allocating a new full segment. 113 */ 114 struct buffer_head *ns_sbh[2]; 115 struct nilfs_super_block *ns_sbp[2]; 116 time_t ns_sbwtime; 117 unsigned int ns_sbwcount; 118 unsigned int ns_sbsize; 119 unsigned int ns_mount_state; 120 unsigned int ns_sb_update_freq; 121 122 /* 123 * Following fields are dedicated to a writable FS-instance. 124 * Except for the period seeking checkpoint, code outside the segment 125 * constructor must lock a segment semaphore while accessing these 126 * fields. 127 * The writable FS-instance is sole during a lifetime of the_nilfs. 128 */ 129 u64 ns_seg_seq; 130 __u64 ns_segnum; 131 __u64 ns_nextnum; 132 unsigned long ns_pseg_offset; 133 __u64 ns_cno; 134 time_t ns_ctime; 135 time_t ns_nongc_ctime; 136 atomic_t ns_ndirtyblks; 137 138 /* 139 * The following fields hold information on the latest partial segment 140 * written to disk with a super root. These fields are protected by 141 * ns_last_segment_lock. 142 */ 143 spinlock_t ns_last_segment_lock; 144 sector_t ns_last_pseg; 145 u64 ns_last_seq; 146 __u64 ns_last_cno; 147 u64 ns_prot_seq; 148 u64 ns_prev_seq; 149 150 struct nilfs_sc_info *ns_writer; 151 struct rw_semaphore ns_segctor_sem; 152 153 /* 154 * Following fields are lock free except for the period before 155 * the_nilfs is initialized. 156 */ 157 struct inode *ns_dat; 158 struct inode *ns_cpfile; 159 struct inode *ns_sufile; 160 161 /* Checkpoint tree */ 162 struct rb_root ns_cptree; 163 spinlock_t ns_cptree_lock; 164 165 /* Dirty inode list */ 166 struct list_head ns_dirty_files; 167 spinlock_t ns_inode_lock; 168 169 /* GC inode list */ 170 struct list_head ns_gc_inodes; 171 172 /* Inode allocator */ 173 u32 ns_next_generation; 174 spinlock_t ns_next_gen_lock; 175 176 /* Mount options */ 177 unsigned long ns_mount_opt; 178 179 uid_t ns_resuid; 180 gid_t ns_resgid; 181 unsigned long ns_interval; 182 unsigned long ns_watermark; 183 184 /* Disk layout information (static) */ 185 unsigned int ns_blocksize_bits; 186 unsigned int ns_blocksize; 187 unsigned long ns_nsegments; 188 unsigned long ns_blocks_per_segment; 189 unsigned long ns_r_segments_percentage; 190 unsigned long ns_nrsvsegs; 191 unsigned long ns_first_data_block; 192 int ns_inode_size; 193 int ns_first_ino; 194 u32 ns_crc_seed; 195 196 /* /sys/fs/<nilfs>/<device> */ 197 struct kobject ns_dev_kobj; 198 struct completion ns_dev_kobj_unregister; 199 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups; 200 }; 201 202 #define THE_NILFS_FNS(bit, name) \ 203 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ 204 { \ 205 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 206 } \ 207 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ 208 { \ 209 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 210 } \ 211 static inline int nilfs_##name(struct the_nilfs *nilfs) \ 212 { \ 213 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 214 } 215 216 THE_NILFS_FNS(INIT, init) 217 THE_NILFS_FNS(DISCONTINUED, discontinued) 218 THE_NILFS_FNS(GC_RUNNING, gc_running) 219 THE_NILFS_FNS(SB_DIRTY, sb_dirty) 220 221 /* 222 * Mount option operations 223 */ 224 #define nilfs_clear_opt(nilfs, opt) \ 225 ((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt) 226 #define nilfs_set_opt(nilfs, opt) \ 227 ((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt) 228 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt) 229 #define nilfs_write_opt(nilfs, mask, opt) \ 230 ((nilfs)->ns_mount_opt = \ 231 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \ 232 NILFS_MOUNT_##opt)) \ 233 234 /** 235 * struct nilfs_root - nilfs root object 236 * @cno: checkpoint number 237 * @rb_node: red-black tree node 238 * @count: refcount of this structure 239 * @nilfs: nilfs object 240 * @ifile: inode file 241 * @inodes_count: number of inodes 242 * @blocks_count: number of blocks 243 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> 244 * @snapshot_kobj_unregister: completion state for kernel object 245 */ 246 struct nilfs_root { 247 __u64 cno; 248 struct rb_node rb_node; 249 250 atomic_t count; 251 struct the_nilfs *nilfs; 252 struct inode *ifile; 253 254 atomic64_t inodes_count; 255 atomic64_t blocks_count; 256 257 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */ 258 struct kobject snapshot_kobj; 259 struct completion snapshot_kobj_unregister; 260 }; 261 262 /* Special checkpoint number */ 263 #define NILFS_CPTREE_CURRENT_CNO 0 264 265 /* Minimum interval of periodical update of superblocks (in seconds) */ 266 #define NILFS_SB_FREQ 10 267 268 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) 269 { 270 u64 t = get_seconds(); 271 272 return t < nilfs->ns_sbwtime || 273 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq; 274 } 275 276 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs) 277 { 278 int flip_bits = nilfs->ns_sbwcount & 0x0FL; 279 280 return (flip_bits != 0x08 && flip_bits != 0x0F); 281 } 282 283 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); 284 struct the_nilfs *alloc_nilfs(struct block_device *bdev); 285 void destroy_nilfs(struct the_nilfs *nilfs); 286 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data); 287 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb); 288 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs); 289 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs); 290 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t); 291 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); 292 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno); 293 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs, 294 __u64 cno); 295 void nilfs_put_root(struct nilfs_root *root); 296 int nilfs_near_disk_full(struct the_nilfs *); 297 void nilfs_fall_back_super_block(struct the_nilfs *); 298 void nilfs_swap_super_block(struct the_nilfs *); 299 300 301 static inline void nilfs_get_root(struct nilfs_root *root) 302 { 303 atomic_inc(&root->count); 304 } 305 306 static inline int nilfs_valid_fs(struct the_nilfs *nilfs) 307 { 308 unsigned int valid_fs; 309 310 down_read(&nilfs->ns_sem); 311 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); 312 up_read(&nilfs->ns_sem); 313 return valid_fs; 314 } 315 316 static inline void 317 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, 318 sector_t *seg_start, sector_t *seg_end) 319 { 320 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; 321 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; 322 if (segnum == 0) 323 *seg_start = nilfs->ns_first_data_block; 324 } 325 326 static inline sector_t 327 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) 328 { 329 return (segnum == 0) ? nilfs->ns_first_data_block : 330 (sector_t)nilfs->ns_blocks_per_segment * segnum; 331 } 332 333 static inline __u64 334 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) 335 { 336 sector_t segnum = blocknr; 337 338 sector_div(segnum, nilfs->ns_blocks_per_segment); 339 return segnum; 340 } 341 342 static inline void 343 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, 344 sector_t seg_end) 345 { 346 /* terminate the current full segment (used in case of I/O-error) */ 347 nilfs->ns_pseg_offset = seg_end - seg_start + 1; 348 } 349 350 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) 351 { 352 /* move forward with a full segment */ 353 nilfs->ns_segnum = nilfs->ns_nextnum; 354 nilfs->ns_pseg_offset = 0; 355 nilfs->ns_seg_seq++; 356 } 357 358 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) 359 { 360 __u64 cno; 361 362 spin_lock(&nilfs->ns_last_segment_lock); 363 cno = nilfs->ns_last_cno; 364 spin_unlock(&nilfs->ns_last_segment_lock); 365 return cno; 366 } 367 368 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) 369 { 370 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; 371 } 372 373 static inline int nilfs_flush_device(struct the_nilfs *nilfs) 374 { 375 int err; 376 377 if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device) 378 return 0; 379 380 nilfs->ns_flushed_device = 1; 381 /* 382 * the store to ns_flushed_device must not be reordered after 383 * blkdev_issue_flush(). 384 */ 385 smp_wmb(); 386 387 err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL, NULL); 388 if (err != -EIO) 389 err = 0; 390 return err; 391 } 392 393 #endif /* _THE_NILFS_H */ 394