fs/nilfs2/the_nilfs.h

   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 };
  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);
 379         if (err != -EIO)
 380                 err = 0;
 381         return err;
 382 }
 383
 384 #endif /* _THE_NILFS_H */