fs/nilfs2/the_nilfs.h

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