1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * the_nilfs shared structure. 4 * 5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. 6 * 7 * Written by Ryusuke Konishi. 8 * 9 */ 10 11 #ifndef _THE_NILFS_H 12 #define _THE_NILFS_H 13 14 #include <linux/types.h> 15 #include <linux/buffer_head.h> 16 #include <linux/rbtree.h> 17 #include <linux/fs.h> 18 #include <linux/blkdev.h> 19 #include <linux/backing-dev.h> 20 #include <linux/slab.h> 21 #include <linux/refcount.h> 22 23 struct nilfs_sc_info; 24 struct nilfs_sysfs_dev_subgroups; 25 26 /* the_nilfs struct */ 27 enum { 28 THE_NILFS_INIT = 0, /* Information from super_block is set */ 29 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ 30 THE_NILFS_GC_RUNNING, /* gc process is running */ 31 THE_NILFS_SB_DIRTY, /* super block is dirty */ 32 THE_NILFS_PURGING, /* disposing dirty files for cleanup */ 33 }; 34 35 /** 36 * struct the_nilfs - struct to supervise multiple nilfs mount points 37 * @ns_flags: flags 38 * @ns_flushed_device: flag indicating if all volatile data was flushed 39 * @ns_sb: back pointer to super block instance 40 * @ns_bdev: block device 41 * @ns_sem: semaphore for shared states 42 * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts 43 * @ns_sbh: buffer heads of on-disk super blocks 44 * @ns_sbp: pointers to super block data 45 * @ns_sbwtime: previous write time of super block 46 * @ns_sbwcount: write count of super block 47 * @ns_sbsize: size of valid data in super block 48 * @ns_mount_state: file system state 49 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds) 50 * @ns_seg_seq: segment sequence counter 51 * @ns_segnum: index number of the latest full segment. 52 * @ns_nextnum: index number of the full segment index to be used next 53 * @ns_pseg_offset: offset of next partial segment in the current full segment 54 * @ns_cno: next checkpoint number 55 * @ns_ctime: write time of the last segment 56 * @ns_nongc_ctime: write time of the last segment not for cleaner operation 57 * @ns_ndirtyblks: Number of dirty data blocks 58 * @ns_last_segment_lock: lock protecting fields for the latest segment 59 * @ns_last_pseg: start block number of the latest segment 60 * @ns_last_seq: sequence value of the latest segment 61 * @ns_last_cno: checkpoint number of the latest segment 62 * @ns_prot_seq: least sequence number of segments which must not be reclaimed 63 * @ns_prev_seq: base sequence number used to decide if advance log cursor 64 * @ns_writer: log writer 65 * @ns_segctor_sem: semaphore protecting log write 66 * @ns_dat: DAT file inode 67 * @ns_cpfile: checkpoint file inode 68 * @ns_sufile: segusage file inode 69 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root) 70 * @ns_cptree_lock: lock protecting @ns_cptree 71 * @ns_dirty_files: list of dirty files 72 * @ns_inode_lock: lock protecting @ns_dirty_files 73 * @ns_gc_inodes: dummy inodes to keep live blocks 74 * @ns_next_generation: next generation number for inodes 75 * @ns_next_gen_lock: lock protecting @ns_next_generation 76 * @ns_mount_opt: mount options 77 * @ns_resuid: uid for reserved blocks 78 * @ns_resgid: gid for reserved blocks 79 * @ns_interval: checkpoint creation interval 80 * @ns_watermark: watermark for the number of dirty buffers 81 * @ns_blocksize_bits: bit length of block size 82 * @ns_blocksize: block size 83 * @ns_nsegments: number of segments in filesystem 84 * @ns_blocks_per_segment: number of blocks per segment 85 * @ns_r_segments_percentage: reserved segments percentage 86 * @ns_nrsvsegs: number of reserved segments 87 * @ns_first_data_block: block number of first data block 88 * @ns_inode_size: size of on-disk inode 89 * @ns_first_ino: first not-special inode number 90 * @ns_crc_seed: seed value of CRC32 calculation 91 * @ns_dev_kobj: /sys/fs/<nilfs>/<device> 92 * @ns_dev_kobj_unregister: completion state 93 * @ns_dev_subgroups: <device> subgroups pointer 94 */ 95 struct the_nilfs { 96 unsigned long ns_flags; 97 int ns_flushed_device; 98 99 struct super_block *ns_sb; 100 struct block_device *ns_bdev; 101 struct rw_semaphore ns_sem; 102 struct mutex ns_snapshot_mount_mutex; 103 104 /* 105 * used for 106 * - loading the latest checkpoint exclusively. 107 * - allocating a new full segment. 108 */ 109 struct buffer_head *ns_sbh[2]; 110 struct nilfs_super_block *ns_sbp[2]; 111 time64_t ns_sbwtime; 112 unsigned int ns_sbwcount; 113 unsigned int ns_sbsize; 114 unsigned int ns_mount_state; 115 unsigned int ns_sb_update_freq; 116 117 /* 118 * The following fields are updated by a writable FS-instance. 119 * These fields are protected by ns_segctor_sem outside load_nilfs(). 120 */ 121 u64 ns_seg_seq; 122 __u64 ns_segnum; 123 __u64 ns_nextnum; 124 unsigned long ns_pseg_offset; 125 __u64 ns_cno; 126 time64_t ns_ctime; 127 time64_t ns_nongc_ctime; 128 atomic_t ns_ndirtyblks; 129 130 /* 131 * The following fields hold information on the latest partial segment 132 * written to disk with a super root. These fields are protected by 133 * ns_last_segment_lock. 134 */ 135 spinlock_t ns_last_segment_lock; 136 sector_t ns_last_pseg; 137 u64 ns_last_seq; 138 __u64 ns_last_cno; 139 u64 ns_prot_seq; 140 u64 ns_prev_seq; 141 142 struct nilfs_sc_info *ns_writer; 143 struct rw_semaphore ns_segctor_sem; 144 145 /* 146 * Following fields are lock free except for the period before 147 * the_nilfs is initialized. 148 */ 149 struct inode *ns_dat; 150 struct inode *ns_cpfile; 151 struct inode *ns_sufile; 152 153 /* Checkpoint tree */ 154 struct rb_root ns_cptree; 155 spinlock_t ns_cptree_lock; 156 157 /* Dirty inode list */ 158 struct list_head ns_dirty_files; 159 spinlock_t ns_inode_lock; 160 161 /* GC inode list */ 162 struct list_head ns_gc_inodes; 163 164 /* Inode allocator */ 165 u32 ns_next_generation; 166 spinlock_t ns_next_gen_lock; 167 168 /* Mount options */ 169 unsigned long ns_mount_opt; 170 171 uid_t ns_resuid; 172 gid_t ns_resgid; 173 unsigned long ns_interval; 174 unsigned long ns_watermark; 175 176 /* Disk layout information (static) */ 177 unsigned int ns_blocksize_bits; 178 unsigned int ns_blocksize; 179 unsigned long ns_nsegments; 180 unsigned long ns_blocks_per_segment; 181 unsigned long ns_r_segments_percentage; 182 unsigned long ns_nrsvsegs; 183 unsigned long ns_first_data_block; 184 int ns_inode_size; 185 int ns_first_ino; 186 u32 ns_crc_seed; 187 188 /* /sys/fs/<nilfs>/<device> */ 189 struct kobject ns_dev_kobj; 190 struct completion ns_dev_kobj_unregister; 191 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups; 192 }; 193 194 #define THE_NILFS_FNS(bit, name) \ 195 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ 196 { \ 197 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 198 } \ 199 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ 200 { \ 201 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 202 } \ 203 static inline int nilfs_##name(struct the_nilfs *nilfs) \ 204 { \ 205 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 206 } 207 208 THE_NILFS_FNS(INIT, init) 209 THE_NILFS_FNS(DISCONTINUED, discontinued) 210 THE_NILFS_FNS(GC_RUNNING, gc_running) 211 THE_NILFS_FNS(SB_DIRTY, sb_dirty) 212 THE_NILFS_FNS(PURGING, purging) 213 214 /* 215 * Mount option operations 216 */ 217 #define nilfs_clear_opt(nilfs, opt) \ 218 ((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt) 219 #define nilfs_set_opt(nilfs, opt) \ 220 ((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt) 221 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt) 222 223 /** 224 * struct nilfs_root - nilfs root object 225 * @cno: checkpoint number 226 * @rb_node: red-black tree node 227 * @count: refcount of this structure 228 * @nilfs: nilfs object 229 * @ifile: inode file 230 * @inodes_count: number of inodes 231 * @blocks_count: number of blocks 232 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> 233 * @snapshot_kobj_unregister: completion state for kernel object 234 */ 235 struct nilfs_root { 236 __u64 cno; 237 struct rb_node rb_node; 238 239 refcount_t count; 240 struct the_nilfs *nilfs; 241 struct inode *ifile; 242 243 atomic64_t inodes_count; 244 atomic64_t blocks_count; 245 246 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */ 247 struct kobject snapshot_kobj; 248 struct completion snapshot_kobj_unregister; 249 }; 250 251 /* Special checkpoint number */ 252 #define NILFS_CPTREE_CURRENT_CNO 0 253 254 /* Minimum interval of periodical update of superblocks (in seconds) */ 255 #define NILFS_SB_FREQ 10 256 257 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) 258 { 259 u64 t = ktime_get_real_seconds(); 260 261 return t < nilfs->ns_sbwtime || 262 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq; 263 } 264 265 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs) 266 { 267 int flip_bits = nilfs->ns_sbwcount & 0x0FL; 268 269 return (flip_bits != 0x08 && flip_bits != 0x0F); 270 } 271 272 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); 273 struct the_nilfs *alloc_nilfs(struct super_block *sb); 274 void destroy_nilfs(struct the_nilfs *nilfs); 275 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb); 276 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb); 277 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs); 278 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs); 279 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t); 280 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); 281 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno); 282 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs, 283 __u64 cno); 284 void nilfs_put_root(struct nilfs_root *root); 285 int nilfs_near_disk_full(struct the_nilfs *); 286 void nilfs_fall_back_super_block(struct the_nilfs *); 287 void nilfs_swap_super_block(struct the_nilfs *); 288 289 290 static inline void nilfs_get_root(struct nilfs_root *root) 291 { 292 refcount_inc(&root->count); 293 } 294 295 static inline int nilfs_valid_fs(struct the_nilfs *nilfs) 296 { 297 unsigned int valid_fs; 298 299 down_read(&nilfs->ns_sem); 300 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); 301 up_read(&nilfs->ns_sem); 302 return valid_fs; 303 } 304 305 static inline void 306 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, 307 sector_t *seg_start, sector_t *seg_end) 308 { 309 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; 310 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; 311 if (segnum == 0) 312 *seg_start = nilfs->ns_first_data_block; 313 } 314 315 static inline sector_t 316 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) 317 { 318 return (segnum == 0) ? nilfs->ns_first_data_block : 319 (sector_t)nilfs->ns_blocks_per_segment * segnum; 320 } 321 322 static inline __u64 323 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) 324 { 325 sector_t segnum = blocknr; 326 327 sector_div(segnum, nilfs->ns_blocks_per_segment); 328 return segnum; 329 } 330 331 static inline void 332 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, 333 sector_t seg_end) 334 { 335 /* terminate the current full segment (used in case of I/O-error) */ 336 nilfs->ns_pseg_offset = seg_end - seg_start + 1; 337 } 338 339 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) 340 { 341 /* move forward with a full segment */ 342 nilfs->ns_segnum = nilfs->ns_nextnum; 343 nilfs->ns_pseg_offset = 0; 344 nilfs->ns_seg_seq++; 345 } 346 347 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) 348 { 349 __u64 cno; 350 351 spin_lock(&nilfs->ns_last_segment_lock); 352 cno = nilfs->ns_last_cno; 353 spin_unlock(&nilfs->ns_last_segment_lock); 354 return cno; 355 } 356 357 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) 358 { 359 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; 360 } 361 362 static inline int nilfs_flush_device(struct the_nilfs *nilfs) 363 { 364 int err; 365 366 if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device) 367 return 0; 368 369 nilfs->ns_flushed_device = 1; 370 /* 371 * the store to ns_flushed_device must not be reordered after 372 * blkdev_issue_flush(). 373 */ 374 smp_wmb(); 375 376 err = blkdev_issue_flush(nilfs->ns_bdev); 377 if (err != -EIO) 378 err = 0; 379 return err; 380 } 381 382 #endif /* _THE_NILFS_H */ 383