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 #include "sb.h" 35 36 /* the_nilfs struct */ 37 enum { 38 THE_NILFS_INIT = 0, /* Information from super_block is set */ 39 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ 40 THE_NILFS_GC_RUNNING, /* gc process is running */ 41 THE_NILFS_SB_DIRTY, /* super block is dirty */ 42 }; 43 44 /** 45 * struct the_nilfs - struct to supervise multiple nilfs mount points 46 * @ns_flags: flags 47 * @ns_bdev: block device 48 * @ns_sem: semaphore for shared states 49 * @ns_sbh: buffer heads of on-disk super blocks 50 * @ns_sbp: pointers to super block data 51 * @ns_sbwtime: previous write time of super block 52 * @ns_sbwcount: write count of super block 53 * @ns_sbsize: size of valid data in super block 54 * @ns_seg_seq: segment sequence counter 55 * @ns_segnum: index number of the latest full segment. 56 * @ns_nextnum: index number of the full segment index to be used next 57 * @ns_pseg_offset: offset of next partial segment in the current full segment 58 * @ns_cno: next checkpoint number 59 * @ns_ctime: write time of the last segment 60 * @ns_nongc_ctime: write time of the last segment not for cleaner operation 61 * @ns_ndirtyblks: Number of dirty data blocks 62 * @ns_last_segment_lock: lock protecting fields for the latest segment 63 * @ns_last_pseg: start block number of the latest segment 64 * @ns_last_seq: sequence value of the latest segment 65 * @ns_last_cno: checkpoint number of the latest segment 66 * @ns_prot_seq: least sequence number of segments which must not be reclaimed 67 * @ns_prev_seq: base sequence number used to decide if advance log cursor 68 * @ns_segctor_sem: segment constructor semaphore 69 * @ns_dat: DAT file inode 70 * @ns_cpfile: checkpoint file inode 71 * @ns_sufile: segusage file inode 72 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root) 73 * @ns_cptree_lock: lock protecting @ns_cptree 74 * @ns_gc_inodes: dummy inodes to keep live blocks 75 * @ns_blocksize_bits: bit length of block size 76 * @ns_blocksize: block size 77 * @ns_nsegments: number of segments in filesystem 78 * @ns_blocks_per_segment: number of blocks per segment 79 * @ns_r_segments_percentage: reserved segments percentage 80 * @ns_nrsvsegs: number of reserved segments 81 * @ns_first_data_block: block number of first data block 82 * @ns_inode_size: size of on-disk inode 83 * @ns_first_ino: first not-special inode number 84 * @ns_crc_seed: seed value of CRC32 calculation 85 */ 86 struct the_nilfs { 87 unsigned long ns_flags; 88 89 struct block_device *ns_bdev; 90 struct rw_semaphore ns_sem; 91 92 /* 93 * used for 94 * - loading the latest checkpoint exclusively. 95 * - allocating a new full segment. 96 * - protecting s_dirt in the super_block struct 97 * (see nilfs_write_super) and the following fields. 98 */ 99 struct buffer_head *ns_sbh[2]; 100 struct nilfs_super_block *ns_sbp[2]; 101 time_t ns_sbwtime; 102 unsigned ns_sbwcount; 103 unsigned ns_sbsize; 104 unsigned ns_mount_state; 105 106 /* 107 * Following fields are dedicated to a writable FS-instance. 108 * Except for the period seeking checkpoint, code outside the segment 109 * constructor must lock a segment semaphore while accessing these 110 * fields. 111 * The writable FS-instance is sole during a lifetime of the_nilfs. 112 */ 113 u64 ns_seg_seq; 114 __u64 ns_segnum; 115 __u64 ns_nextnum; 116 unsigned long ns_pseg_offset; 117 __u64 ns_cno; 118 time_t ns_ctime; 119 time_t ns_nongc_ctime; 120 atomic_t ns_ndirtyblks; 121 122 /* 123 * The following fields hold information on the latest partial segment 124 * written to disk with a super root. These fields are protected by 125 * ns_last_segment_lock. 126 */ 127 spinlock_t ns_last_segment_lock; 128 sector_t ns_last_pseg; 129 u64 ns_last_seq; 130 __u64 ns_last_cno; 131 u64 ns_prot_seq; 132 u64 ns_prev_seq; 133 134 struct rw_semaphore ns_segctor_sem; 135 136 /* 137 * Following fields are lock free except for the period before 138 * the_nilfs is initialized. 139 */ 140 struct inode *ns_dat; 141 struct inode *ns_cpfile; 142 struct inode *ns_sufile; 143 144 /* Checkpoint tree */ 145 struct rb_root ns_cptree; 146 spinlock_t ns_cptree_lock; 147 148 /* GC inode list */ 149 struct list_head ns_gc_inodes; 150 151 /* Disk layout information (static) */ 152 unsigned int ns_blocksize_bits; 153 unsigned int ns_blocksize; 154 unsigned long ns_nsegments; 155 unsigned long ns_blocks_per_segment; 156 unsigned long ns_r_segments_percentage; 157 unsigned long ns_nrsvsegs; 158 unsigned long ns_first_data_block; 159 int ns_inode_size; 160 int ns_first_ino; 161 u32 ns_crc_seed; 162 }; 163 164 #define THE_NILFS_FNS(bit, name) \ 165 static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ 166 { \ 167 set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 168 } \ 169 static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ 170 { \ 171 clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 172 } \ 173 static inline int nilfs_##name(struct the_nilfs *nilfs) \ 174 { \ 175 return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ 176 } 177 178 THE_NILFS_FNS(INIT, init) 179 THE_NILFS_FNS(DISCONTINUED, discontinued) 180 THE_NILFS_FNS(GC_RUNNING, gc_running) 181 THE_NILFS_FNS(SB_DIRTY, sb_dirty) 182 183 /** 184 * struct nilfs_root - nilfs root object 185 * @cno: checkpoint number 186 * @rb_node: red-black tree node 187 * @count: refcount of this structure 188 * @nilfs: nilfs object 189 * @ifile: inode file 190 * @root: root inode 191 * @inodes_count: number of inodes 192 * @blocks_count: number of blocks (Reserved) 193 */ 194 struct nilfs_root { 195 __u64 cno; 196 struct rb_node rb_node; 197 198 atomic_t count; 199 struct the_nilfs *nilfs; 200 struct inode *ifile; 201 202 atomic_t inodes_count; 203 atomic_t blocks_count; 204 }; 205 206 /* Special checkpoint number */ 207 #define NILFS_CPTREE_CURRENT_CNO 0 208 209 /* Minimum interval of periodical update of superblocks (in seconds) */ 210 #define NILFS_SB_FREQ 10 211 212 static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) 213 { 214 u64 t = get_seconds(); 215 return t < nilfs->ns_sbwtime || t > nilfs->ns_sbwtime + NILFS_SB_FREQ; 216 } 217 218 static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs) 219 { 220 int flip_bits = nilfs->ns_sbwcount & 0x0FL; 221 return (flip_bits != 0x08 && flip_bits != 0x0F); 222 } 223 224 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); 225 struct the_nilfs *alloc_nilfs(struct block_device *bdev); 226 void destroy_nilfs(struct the_nilfs *nilfs); 227 int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *); 228 int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *); 229 int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t); 230 int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); 231 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno); 232 struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs, 233 __u64 cno); 234 void nilfs_put_root(struct nilfs_root *root); 235 struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64); 236 int nilfs_near_disk_full(struct the_nilfs *); 237 void nilfs_fall_back_super_block(struct the_nilfs *); 238 void nilfs_swap_super_block(struct the_nilfs *); 239 240 241 static inline void nilfs_get_root(struct nilfs_root *root) 242 { 243 atomic_inc(&root->count); 244 } 245 246 static inline int nilfs_valid_fs(struct the_nilfs *nilfs) 247 { 248 unsigned valid_fs; 249 250 down_read(&nilfs->ns_sem); 251 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); 252 up_read(&nilfs->ns_sem); 253 return valid_fs; 254 } 255 256 static inline void 257 nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, 258 sector_t *seg_start, sector_t *seg_end) 259 { 260 *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; 261 *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; 262 if (segnum == 0) 263 *seg_start = nilfs->ns_first_data_block; 264 } 265 266 static inline sector_t 267 nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) 268 { 269 return (segnum == 0) ? nilfs->ns_first_data_block : 270 (sector_t)nilfs->ns_blocks_per_segment * segnum; 271 } 272 273 static inline __u64 274 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) 275 { 276 sector_t segnum = blocknr; 277 278 sector_div(segnum, nilfs->ns_blocks_per_segment); 279 return segnum; 280 } 281 282 static inline void 283 nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, 284 sector_t seg_end) 285 { 286 /* terminate the current full segment (used in case of I/O-error) */ 287 nilfs->ns_pseg_offset = seg_end - seg_start + 1; 288 } 289 290 static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) 291 { 292 /* move forward with a full segment */ 293 nilfs->ns_segnum = nilfs->ns_nextnum; 294 nilfs->ns_pseg_offset = 0; 295 nilfs->ns_seg_seq++; 296 } 297 298 static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) 299 { 300 __u64 cno; 301 302 spin_lock(&nilfs->ns_last_segment_lock); 303 cno = nilfs->ns_last_cno; 304 spin_unlock(&nilfs->ns_last_segment_lock); 305 return cno; 306 } 307 308 static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) 309 { 310 return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; 311 } 312 313 #endif /* _THE_NILFS_H */ 314