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 35struct nilfs_sc_info; 36struct nilfs_sysfs_dev_subgroups; 37 38/* the_nilfs struct */ 39enum { 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_flushed_device: flag indicating if all volatile data was flushed 50 * @ns_bdev: block device 51 * @ns_sem: semaphore for shared states 52 * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts 53 * @ns_sbh: buffer heads of on-disk super blocks 54 * @ns_sbp: pointers to super block data 55 * @ns_sbwtime: previous write time of super block 56 * @ns_sbwcount: write count of super block 57 * @ns_sbsize: size of valid data in super block 58 * @ns_mount_state: file system state 59 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds) 60 * @ns_seg_seq: segment sequence counter 61 * @ns_segnum: index number of the latest full segment. 62 * @ns_nextnum: index number of the full segment index to be used next 63 * @ns_pseg_offset: offset of next partial segment in the current full segment 64 * @ns_cno: next checkpoint number 65 * @ns_ctime: write time of the last segment 66 * @ns_nongc_ctime: write time of the last segment not for cleaner operation 67 * @ns_ndirtyblks: Number of dirty data blocks 68 * @ns_last_segment_lock: lock protecting fields for the latest segment 69 * @ns_last_pseg: start block number of the latest segment 70 * @ns_last_seq: sequence value of the latest segment 71 * @ns_last_cno: checkpoint number of the latest segment 72 * @ns_prot_seq: least sequence number of segments which must not be reclaimed 73 * @ns_prev_seq: base sequence number used to decide if advance log cursor 74 * @ns_writer: log writer 75 * @ns_segctor_sem: semaphore protecting log write 76 * @ns_dat: DAT file inode 77 * @ns_cpfile: checkpoint file inode 78 * @ns_sufile: segusage file inode 79 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root) 80 * @ns_cptree_lock: lock protecting @ns_cptree 81 * @ns_dirty_files: list of dirty files 82 * @ns_inode_lock: lock protecting @ns_dirty_files 83 * @ns_gc_inodes: dummy inodes to keep live blocks 84 * @ns_next_generation: next generation number for inodes 85 * @ns_next_gen_lock: lock protecting @ns_next_generation 86 * @ns_mount_opt: mount options 87 * @ns_resuid: uid for reserved blocks 88 * @ns_resgid: gid for reserved blocks 89 * @ns_interval: checkpoint creation interval 90 * @ns_watermark: watermark for the number of dirty buffers 91 * @ns_blocksize_bits: bit length of block size 92 * @ns_blocksize: block size 93 * @ns_nsegments: number of segments in filesystem 94 * @ns_blocks_per_segment: number of blocks per segment 95 * @ns_r_segments_percentage: reserved segments percentage 96 * @ns_nrsvsegs: number of reserved segments 97 * @ns_first_data_block: block number of first data block 98 * @ns_inode_size: size of on-disk inode 99 * @ns_first_ino: first not-special inode number 100 * @ns_crc_seed: seed value of CRC32 calculation 101 * @ns_dev_kobj: /sys/fs/<nilfs>/<device> 102 * @ns_dev_kobj_unregister: completion state 103 * @ns_dev_subgroups: <device> subgroups pointer 104 */ 105struct the_nilfs { 106 unsigned long ns_flags; 107 int ns_flushed_device; 108 109 struct block_device *ns_bdev; 110 struct rw_semaphore ns_sem; 111 struct mutex ns_snapshot_mount_mutex; 112 113 /* 114 * used for 115 * - loading the latest checkpoint exclusively. 116 * - allocating a new full segment. 117 */ 118 struct buffer_head *ns_sbh[2]; 119 struct nilfs_super_block *ns_sbp[2]; 120 time_t ns_sbwtime; 121 unsigned ns_sbwcount; 122 unsigned ns_sbsize; 123 unsigned ns_mount_state; 124 unsigned ns_sb_update_freq; 125 126 /* 127 * Following fields are dedicated to a writable FS-instance. 128 * Except for the period seeking checkpoint, code outside the segment 129 * constructor must lock a segment semaphore while accessing these 130 * fields. 131 * The writable FS-instance is sole during a lifetime of the_nilfs. 132 */ 133 u64 ns_seg_seq; 134 __u64 ns_segnum; 135 __u64 ns_nextnum; 136 unsigned long ns_pseg_offset; 137 __u64 ns_cno; 138 time_t ns_ctime; 139 time_t ns_nongc_ctime; 140 atomic_t ns_ndirtyblks; 141 142 /* 143 * The following fields hold information on the latest partial segment 144 * written to disk with a super root. These fields are protected by 145 * ns_last_segment_lock. 146 */ 147 spinlock_t ns_last_segment_lock; 148 sector_t ns_last_pseg; 149 u64 ns_last_seq; 150 __u64 ns_last_cno; 151 u64 ns_prot_seq; 152 u64 ns_prev_seq; 153 154 struct nilfs_sc_info *ns_writer; 155 struct rw_semaphore ns_segctor_sem; 156 157 /* 158 * Following fields are lock free except for the period before 159 * the_nilfs is initialized. 160 */ 161 struct inode *ns_dat; 162 struct inode *ns_cpfile; 163 struct inode *ns_sufile; 164 165 /* Checkpoint tree */ 166 struct rb_root ns_cptree; 167 spinlock_t ns_cptree_lock; 168 169 /* Dirty inode list */ 170 struct list_head ns_dirty_files; 171 spinlock_t ns_inode_lock; 172 173 /* GC inode list */ 174 struct list_head ns_gc_inodes; 175 176 /* Inode allocator */ 177 u32 ns_next_generation; 178 spinlock_t ns_next_gen_lock; 179 180 /* Mount options */ 181 unsigned long ns_mount_opt; 182 183 uid_t ns_resuid; 184 gid_t ns_resgid; 185 unsigned long ns_interval; 186 unsigned long ns_watermark; 187 188 /* Disk layout information (static) */ 189 unsigned int ns_blocksize_bits; 190 unsigned int ns_blocksize; 191 unsigned long ns_nsegments; 192 unsigned long ns_blocks_per_segment; 193 unsigned long ns_r_segments_percentage; 194 unsigned long ns_nrsvsegs; 195 unsigned long ns_first_data_block; 196 int ns_inode_size; 197 int ns_first_ino; 198 u32 ns_crc_seed; 199 200 /* /sys/fs/<nilfs>/<device> */ 201 struct kobject ns_dev_kobj; 202 struct completion ns_dev_kobj_unregister; 203 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups; 204}; 205 206#define THE_NILFS_FNS(bit, name) \ 207static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ 208{ \ 209 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 210} \ 211static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ 212{ \ 213 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 214} \ 215static inline int nilfs_##name(struct the_nilfs *nilfs) \ 216{ \ 217 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 218} 219 220THE_NILFS_FNS(INIT, init) 221THE_NILFS_FNS(DISCONTINUED, discontinued) 222THE_NILFS_FNS(GC_RUNNING, gc_running) 223THE_NILFS_FNS(SB_DIRTY, sb_dirty) 224 225/* 226 * Mount option operations 227 */ 228#define nilfs_clear_opt(nilfs, opt) \ 229 do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0) 230#define nilfs_set_opt(nilfs, opt) \ 231 do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0) 232#define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt) 233#define nilfs_write_opt(nilfs, mask, opt) \ 234 do { (nilfs)->ns_mount_opt = \ 235 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \ 236 NILFS_MOUNT_##opt); \ 237 } while (0) 238 239/** 240 * struct nilfs_root - nilfs root object 241 * @cno: checkpoint number 242 * @rb_node: red-black tree node 243 * @count: refcount of this structure 244 * @nilfs: nilfs object 245 * @ifile: inode file 246 * @inodes_count: number of inodes 247 * @blocks_count: number of blocks 248 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> 249 * @snapshot_kobj_unregister: completion state for kernel object 250 */ 251struct nilfs_root { 252 __u64 cno; 253 struct rb_node rb_node; 254 255 atomic_t count; 256 struct the_nilfs *nilfs; 257 struct inode *ifile; 258 259 atomic64_t inodes_count; 260 atomic64_t blocks_count; 261 262 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */ 263 struct kobject snapshot_kobj; 264 struct completion snapshot_kobj_unregister; 265}; 266 267/* Special checkpoint number */ 268#define NILFS_CPTREE_CURRENT_CNO 0 269 270/* Minimum interval of periodical update of superblocks (in seconds) */ 271#define NILFS_SB_FREQ 10 272 273static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) 274{ 275 u64 t = get_seconds(); 276 return t < nilfs->ns_sbwtime || 277 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq; 278} 279 280static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs) 281{ 282 int flip_bits = nilfs->ns_sbwcount & 0x0FL; 283 return (flip_bits != 0x08 && flip_bits != 0x0F); 284} 285 286void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); 287struct the_nilfs *alloc_nilfs(struct block_device *bdev); 288void destroy_nilfs(struct the_nilfs *nilfs); 289int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data); 290int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb); 291unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs); 292void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs); 293int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t); 294int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); 295struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno); 296struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs, 297 __u64 cno); 298void nilfs_put_root(struct nilfs_root *root); 299int nilfs_near_disk_full(struct the_nilfs *); 300void nilfs_fall_back_super_block(struct the_nilfs *); 301void nilfs_swap_super_block(struct the_nilfs *); 302 303 304static inline void nilfs_get_root(struct nilfs_root *root) 305{ 306 atomic_inc(&root->count); 307} 308 309static inline int nilfs_valid_fs(struct the_nilfs *nilfs) 310{ 311 unsigned valid_fs; 312 313 down_read(&nilfs->ns_sem); 314 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); 315 up_read(&nilfs->ns_sem); 316 return valid_fs; 317} 318 319static inline void 320nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, 321 sector_t *seg_start, sector_t *seg_end) 322{ 323 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; 324 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; 325 if (segnum == 0) 326 *seg_start = nilfs->ns_first_data_block; 327} 328 329static inline sector_t 330nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) 331{ 332 return (segnum == 0) ? nilfs->ns_first_data_block : 333 (sector_t)nilfs->ns_blocks_per_segment * segnum; 334} 335 336static inline __u64 337nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) 338{ 339 sector_t segnum = blocknr; 340 341 sector_div(segnum, nilfs->ns_blocks_per_segment); 342 return segnum; 343} 344 345static inline void 346nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, 347 sector_t seg_end) 348{ 349 /* terminate the current full segment (used in case of I/O-error) */ 350 nilfs->ns_pseg_offset = seg_end - seg_start + 1; 351} 352 353static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) 354{ 355 /* move forward with a full segment */ 356 nilfs->ns_segnum = nilfs->ns_nextnum; 357 nilfs->ns_pseg_offset = 0; 358 nilfs->ns_seg_seq++; 359} 360 361static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) 362{ 363 __u64 cno; 364 365 spin_lock(&nilfs->ns_last_segment_lock); 366 cno = nilfs->ns_last_cno; 367 spin_unlock(&nilfs->ns_last_segment_lock); 368 return cno; 369} 370 371static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) 372{ 373 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; 374} 375 376static inline int nilfs_flush_device(struct the_nilfs *nilfs) 377{ 378 int err; 379 380 if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device) 381 return 0; 382 383 nilfs->ns_flushed_device = 1; 384 /* 385 * the store to ns_flushed_device must not be reordered after 386 * blkdev_issue_flush(). 387 */ 388 smp_wmb(); 389 390 err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL, NULL); 391 if (err != -EIO) 392 err = 0; 393 return err; 394} 395 396#endif /* _THE_NILFS_H */ 397