1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * the_nilfs.h - 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 }; 33 34 /** 35 * struct the_nilfs - struct to supervise multiple nilfs mount points 36 * @ns_flags: flags 37 * @ns_flushed_device: flag indicating if all volatile data was flushed 38 * @ns_sb: back pointer to super block instance 39 * @ns_bdev: block device 40 * @ns_sem: semaphore for shared states 41 * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts 42 * @ns_sbh: buffer heads of on-disk super blocks 43 * @ns_sbp: pointers to super block data 44 * @ns_sbwtime: previous write time of super block 45 * @ns_sbwcount: write count of super block 46 * @ns_sbsize: size of valid data in super block 47 * @ns_mount_state: file system state 48 * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds) 49 * @ns_seg_seq: segment sequence counter 50 * @ns_segnum: index number of the latest full segment. 51 * @ns_nextnum: index number of the full segment index to be used next 52 * @ns_pseg_offset: offset of next partial segment in the current full segment 53 * @ns_cno: next checkpoint number 54 * @ns_ctime: write time of the last segment 55 * @ns_nongc_ctime: write time of the last segment not for cleaner operation 56 * @ns_ndirtyblks: Number of dirty data blocks 57 * @ns_last_segment_lock: lock protecting fields for the latest segment 58 * @ns_last_pseg: start block number of the latest segment 59 * @ns_last_seq: sequence value of the latest segment 60 * @ns_last_cno: checkpoint number of the latest segment 61 * @ns_prot_seq: least sequence number of segments which must not be reclaimed 62 * @ns_prev_seq: base sequence number used to decide if advance log cursor 63 * @ns_writer: log writer 64 * @ns_segctor_sem: semaphore protecting log write 65 * @ns_dat: DAT file inode 66 * @ns_cpfile: checkpoint file inode 67 * @ns_sufile: segusage file inode 68 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root) 69 * @ns_cptree_lock: lock protecting @ns_cptree 70 * @ns_dirty_files: list of dirty files 71 * @ns_inode_lock: lock protecting @ns_dirty_files 72 * @ns_gc_inodes: dummy inodes to keep live blocks 73 * @ns_next_generation: next generation number for inodes 74 * @ns_next_gen_lock: lock protecting @ns_next_generation 75 * @ns_mount_opt: mount options 76 * @ns_resuid: uid for reserved blocks 77 * @ns_resgid: gid for reserved blocks 78 * @ns_interval: checkpoint creation interval 79 * @ns_watermark: watermark for the number of dirty buffers 80 * @ns_blocksize_bits: bit length of block size 81 * @ns_blocksize: block size 82 * @ns_nsegments: number of segments in filesystem 83 * @ns_blocks_per_segment: number of blocks per segment 84 * @ns_r_segments_percentage: reserved segments percentage 85 * @ns_nrsvsegs: number of reserved segments 86 * @ns_first_data_block: block number of first data block 87 * @ns_inode_size: size of on-disk inode 88 * @ns_first_ino: first not-special inode number 89 * @ns_crc_seed: seed value of CRC32 calculation 90 * @ns_dev_kobj: /sys/fs/<nilfs>/<device> 91 * @ns_dev_kobj_unregister: completion state 92 * @ns_dev_subgroups: <device> subgroups pointer 93 */ 94 struct the_nilfs { 95 unsigned long ns_flags; 96 int ns_flushed_device; 97 98 struct super_block *ns_sb; 99 struct block_device *ns_bdev; 100 struct rw_semaphore ns_sem; 101 struct mutex ns_snapshot_mount_mutex; 102 103 /* 104 * used for 105 * - loading the latest checkpoint exclusively. 106 * - allocating a new full segment. 107 */ 108 struct buffer_head *ns_sbh[2]; 109 struct nilfs_super_block *ns_sbp[2]; 110 time64_t ns_sbwtime; 111 unsigned int ns_sbwcount; 112 unsigned int ns_sbsize; 113 unsigned int ns_mount_state; 114 unsigned int ns_sb_update_freq; 115 116 /* 117 * The following fields are updated by a writable FS-instance. 118 * These fields are protected by ns_segctor_sem outside load_nilfs(). 119 */ 120 u64 ns_seg_seq; 121 __u64 ns_segnum; 122 __u64 ns_nextnum; 123 unsigned long ns_pseg_offset; 124 __u64 ns_cno; 125 time64_t ns_ctime; 126 time64_t ns_nongc_ctime; 127 atomic_t ns_ndirtyblks; 128 129 /* 130 * The following fields hold information on the latest partial segment 131 * written to disk with a super root. These fields are protected by 132 * ns_last_segment_lock. 133 */ 134 spinlock_t ns_last_segment_lock; 135 sector_t ns_last_pseg; 136 u64 ns_last_seq; 137 __u64 ns_last_cno; 138 u64 ns_prot_seq; 139 u64 ns_prev_seq; 140 141 struct nilfs_sc_info *ns_writer; 142 struct rw_semaphore ns_segctor_sem; 143 144 /* 145 * Following fields are lock free except for the period before 146 * the_nilfs is initialized. 147 */ 148 struct inode *ns_dat; 149 struct inode *ns_cpfile; 150 struct inode *ns_sufile; 151 152 /* Checkpoint tree */ 153 struct rb_root ns_cptree; 154 spinlock_t ns_cptree_lock; 155 156 /* Dirty inode list */ 157 struct list_head ns_dirty_files; 158 spinlock_t ns_inode_lock; 159 160 /* GC inode list */ 161 struct list_head ns_gc_inodes; 162 163 /* Inode allocator */ 164 u32 ns_next_generation; 165 spinlock_t ns_next_gen_lock; 166 167 /* Mount options */ 168 unsigned long ns_mount_opt; 169 170 uid_t ns_resuid; 171 gid_t ns_resgid; 172 unsigned long ns_interval; 173 unsigned long ns_watermark; 174 175 /* Disk layout information (static) */ 176 unsigned int ns_blocksize_bits; 177 unsigned int ns_blocksize; 178 unsigned long ns_nsegments; 179 unsigned long ns_blocks_per_segment; 180 unsigned long ns_r_segments_percentage; 181 unsigned long ns_nrsvsegs; 182 unsigned long ns_first_data_block; 183 int ns_inode_size; 184 int ns_first_ino; 185 u32 ns_crc_seed; 186 187 /* /sys/fs/<nilfs>/<device> */ 188 struct kobject ns_dev_kobj; 189 struct completion ns_dev_kobj_unregister; 190 struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups; 191 }; 192 193 #define THE_NILFS_FNS(bit, name) \ 194 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ 195 { \ 196 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 197 } \ 198 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ 199 { \ 200 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 201 } \ 202 static inline int nilfs_##name(struct the_nilfs *nilfs) \ 203 { \ 204 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 205 } 206 207 THE_NILFS_FNS(INIT, init) 208 THE_NILFS_FNS(DISCONTINUED, discontinued) 209 THE_NILFS_FNS(GC_RUNNING, gc_running) 210 THE_NILFS_FNS(SB_DIRTY, sb_dirty) 211 212 /* 213 * Mount option operations 214 */ 215 #define nilfs_clear_opt(nilfs, opt) \ 216 ((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt) 217 #define nilfs_set_opt(nilfs, opt) \ 218 ((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt) 219 #define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt) 220 #define nilfs_write_opt(nilfs, mask, opt) \ 221 ((nilfs)->ns_mount_opt = \ 222 (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \ 223 NILFS_MOUNT_##opt)) \ 224 225 /** 226 * struct nilfs_root - nilfs root object 227 * @cno: checkpoint number 228 * @rb_node: red-black tree node 229 * @count: refcount of this structure 230 * @nilfs: nilfs object 231 * @ifile: inode file 232 * @inodes_count: number of inodes 233 * @blocks_count: number of blocks 234 * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> 235 * @snapshot_kobj_unregister: completion state for kernel object 236 */ 237 struct nilfs_root { 238 __u64 cno; 239 struct rb_node rb_node; 240 241 refcount_t count; 242 struct the_nilfs *nilfs; 243 struct inode *ifile; 244 245 atomic64_t inodes_count; 246 atomic64_t blocks_count; 247 248 /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */ 249 struct kobject snapshot_kobj; 250 struct completion snapshot_kobj_unregister; 251 }; 252 253 /* Special checkpoint number */ 254 #define NILFS_CPTREE_CURRENT_CNO 0 255 256 /* Minimum interval of periodical update of superblocks (in seconds) */ 257 #define NILFS_SB_FREQ 10 258 259 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) 260 { 261 u64 t = ktime_get_real_seconds(); 262 263 return t < nilfs->ns_sbwtime || 264 t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq; 265 } 266 267 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs) 268 { 269 int flip_bits = nilfs->ns_sbwcount & 0x0FL; 270 271 return (flip_bits != 0x08 && flip_bits != 0x0F); 272 } 273 274 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); 275 struct the_nilfs *alloc_nilfs(struct super_block *sb); 276 void destroy_nilfs(struct the_nilfs *nilfs); 277 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data); 278 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb); 279 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs); 280 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs); 281 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t); 282 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); 283 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno); 284 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs, 285 __u64 cno); 286 void nilfs_put_root(struct nilfs_root *root); 287 int nilfs_near_disk_full(struct the_nilfs *); 288 void nilfs_fall_back_super_block(struct the_nilfs *); 289 void nilfs_swap_super_block(struct the_nilfs *); 290 291 292 static inline void nilfs_get_root(struct nilfs_root *root) 293 { 294 refcount_inc(&root->count); 295 } 296 297 static inline int nilfs_valid_fs(struct the_nilfs *nilfs) 298 { 299 unsigned int valid_fs; 300 301 down_read(&nilfs->ns_sem); 302 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); 303 up_read(&nilfs->ns_sem); 304 return valid_fs; 305 } 306 307 static inline void 308 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, 309 sector_t *seg_start, sector_t *seg_end) 310 { 311 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; 312 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; 313 if (segnum == 0) 314 *seg_start = nilfs->ns_first_data_block; 315 } 316 317 static inline sector_t 318 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) 319 { 320 return (segnum == 0) ? nilfs->ns_first_data_block : 321 (sector_t)nilfs->ns_blocks_per_segment * segnum; 322 } 323 324 static inline __u64 325 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) 326 { 327 sector_t segnum = blocknr; 328 329 sector_div(segnum, nilfs->ns_blocks_per_segment); 330 return segnum; 331 } 332 333 static inline void 334 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, 335 sector_t seg_end) 336 { 337 /* terminate the current full segment (used in case of I/O-error) */ 338 nilfs->ns_pseg_offset = seg_end - seg_start + 1; 339 } 340 341 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) 342 { 343 /* move forward with a full segment */ 344 nilfs->ns_segnum = nilfs->ns_nextnum; 345 nilfs->ns_pseg_offset = 0; 346 nilfs->ns_seg_seq++; 347 } 348 349 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) 350 { 351 __u64 cno; 352 353 spin_lock(&nilfs->ns_last_segment_lock); 354 cno = nilfs->ns_last_cno; 355 spin_unlock(&nilfs->ns_last_segment_lock); 356 return cno; 357 } 358 359 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) 360 { 361 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; 362 } 363 364 static inline int nilfs_flush_device(struct the_nilfs *nilfs) 365 { 366 int err; 367 368 if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device) 369 return 0; 370 371 nilfs->ns_flushed_device = 1; 372 /* 373 * the store to ns_flushed_device must not be reordered after 374 * blkdev_issue_flush(). 375 */ 376 smp_wmb(); 377 378 err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL); 379 if (err != -EIO) 380 err = 0; 381 return err; 382 } 383 384 #endif /* _THE_NILFS_H */ 385