fs/nilfs2/segment.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * NILFS segment constructor.
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Written by Ryusuke Konishi.
   8  *
   9  */
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/buffer_head.h>
  13 #include <linux/writeback.h>
  14 #include <linux/bitops.h>
  15 #include <linux/bio.h>
  16 #include <linux/completion.h>
  17 #include <linux/blkdev.h>
  18 #include <linux/backing-dev.h>
  19 #include <linux/freezer.h>
  20 #include <linux/kthread.h>
  21 #include <linux/crc32.h>
  22 #include <linux/pagevec.h>
  23 #include <linux/slab.h>
  24 #include <linux/sched/signal.h>
  25
  26 #include "nilfs.h"
  27 #include "btnode.h"
  28 #include "page.h"
  29 #include "segment.h"
  30 #include "sufile.h"
  31 #include "cpfile.h"
  32 #include "ifile.h"
  33 #include "segbuf.h"
  34
  35
  36 /*
  37  * Segment constructor
  38  */
  39 #define SC_N_INODEVEC   16   /* Size of locally allocated inode vector */
  40
  41 #define SC_MAX_SEGDELTA 64   /*
  42                               * Upper limit of the number of segments
  43                               * appended in collection retry loop
  44                               */
  45
  46 /* Construction mode */
  47 enum {
  48         SC_LSEG_SR = 1, /* Make a logical segment having a super root */
  49         SC_LSEG_DSYNC,  /*
  50                          * Flush data blocks of a given file and make
  51                          * a logical segment without a super root.
  52                          */
  53         SC_FLUSH_FILE,  /*
  54                          * Flush data files, leads to segment writes without
  55                          * creating a checkpoint.
  56                          */
  57         SC_FLUSH_DAT,   /*
  58                          * Flush DAT file.  This also creates segments
  59                          * without a checkpoint.
  60                          */
  61 };
  62
  63 /* Stage numbers of dirty block collection */
  64 enum {
  65         NILFS_ST_INIT = 0,
  66         NILFS_ST_GC,            /* Collecting dirty blocks for GC */
  67         NILFS_ST_FILE,
  68         NILFS_ST_IFILE,
  69         NILFS_ST_CPFILE,
  70         NILFS_ST_SUFILE,
  71         NILFS_ST_DAT,
  72         NILFS_ST_SR,            /* Super root */
  73         NILFS_ST_DSYNC,         /* Data sync blocks */
  74         NILFS_ST_DONE,
  75 };
  76
  77 #define CREATE_TRACE_POINTS
  78 #include <trace/events/nilfs2.h>
  79
  80 /*
  81  * nilfs_sc_cstage_inc(), nilfs_sc_cstage_set(), nilfs_sc_cstage_get() are
  82  * wrapper functions of stage count (nilfs_sc_info->sc_stage.scnt). Users of
  83  * the variable must use them because transition of stage count must involve
  84  * trace events (trace_nilfs2_collection_stage_transition).
  85  *
  86  * nilfs_sc_cstage_get() isn't required for the above purpose because it doesn't
  87  * produce tracepoint events. It is provided just for making the intention
  88  * clear.
  89  */
  90 static inline void nilfs_sc_cstage_inc(struct nilfs_sc_info *sci)
  91 {
  92         sci->sc_stage.scnt++;
  93         trace_nilfs2_collection_stage_transition(sci);
  94 }
  95
  96 static inline void nilfs_sc_cstage_set(struct nilfs_sc_info *sci, int next_scnt)
  97 {
  98         sci->sc_stage.scnt = next_scnt;
  99         trace_nilfs2_collection_stage_transition(sci);
 100 }
 101
 102 static inline int nilfs_sc_cstage_get(struct nilfs_sc_info *sci)
 103 {
 104         return sci->sc_stage.scnt;
 105 }
 106
 107 /* State flags of collection */
 108 #define NILFS_CF_NODE           0x0001  /* Collecting node blocks */
 109 #define NILFS_CF_IFILE_STARTED  0x0002  /* IFILE stage has started */
 110 #define NILFS_CF_SUFREED        0x0004  /* segment usages has been freed */
 111 #define NILFS_CF_HISTORY_MASK   (NILFS_CF_IFILE_STARTED | NILFS_CF_SUFREED)
 112
 113 /* Operations depending on the construction mode and file type */
 114 struct nilfs_sc_operations {
 115         int (*collect_data)(struct nilfs_sc_info *, struct buffer_head *,
 116                             struct inode *);
 117         int (*collect_node)(struct nilfs_sc_info *, struct buffer_head *,
 118                             struct inode *);
 119         int (*collect_bmap)(struct nilfs_sc_info *, struct buffer_head *,
 120                             struct inode *);
 121         void (*write_data_binfo)(struct nilfs_sc_info *,
 122                                  struct nilfs_segsum_pointer *,
 123                                  union nilfs_binfo *);
 124         void (*write_node_binfo)(struct nilfs_sc_info *,
 125                                  struct nilfs_segsum_pointer *,
 126                                  union nilfs_binfo *);
 127 };
 128
 129 /*
 130  * Other definitions
 131  */
 132 static void nilfs_segctor_start_timer(struct nilfs_sc_info *);
 133 static void nilfs_segctor_do_flush(struct nilfs_sc_info *, int);
 134 static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *);
 135 static void nilfs_dispose_list(struct the_nilfs *, struct list_head *, int);
 136
 137 #define nilfs_cnt32_ge(a, b)   \
 138         (typecheck(__u32, a) && typecheck(__u32, b) && \
 139          ((__s32)(a) - (__s32)(b) >= 0))
 140
 141 static int nilfs_prepare_segment_lock(struct super_block *sb,
 142                                       struct nilfs_transaction_info *ti)
 143 {
 144         struct nilfs_transaction_info *cur_ti = current->journal_info;
 145         void *save = NULL;
 146
 147         if (cur_ti) {
 148                 if (cur_ti->ti_magic == NILFS_TI_MAGIC)
 149                         return ++cur_ti->ti_count;
 150
 151                 /*
 152                  * If journal_info field is occupied by other FS,
 153                  * it is saved and will be restored on
 154                  * nilfs_transaction_commit().
 155                  */
 156                 nilfs_warn(sb, "journal info from a different FS");
 157                 save = current->journal_info;
 158         }
 159         if (!ti) {
 160                 ti = kmem_cache_alloc(nilfs_transaction_cachep, GFP_NOFS);
 161                 if (!ti)
 162                         return -ENOMEM;
 163                 ti->ti_flags = NILFS_TI_DYNAMIC_ALLOC;
 164         } else {
 165                 ti->ti_flags = 0;
 166         }
 167         ti->ti_count = 0;
 168         ti->ti_save = save;
 169         ti->ti_magic = NILFS_TI_MAGIC;
 170         current->journal_info = ti;
 171         return 0;
 172 }
 173
 174 /**
 175  * nilfs_transaction_begin - start indivisible file operations.
 176  * @sb: super block
 177  * @ti: nilfs_transaction_info
 178  * @vacancy_check: flags for vacancy rate checks
 179  *
 180  * nilfs_transaction_begin() acquires a reader/writer semaphore, called
 181  * the segment semaphore, to make a segment construction and write tasks
 182  * exclusive.  The function is used with nilfs_transaction_commit() in pairs.
 183  * The region enclosed by these two functions can be nested.  To avoid a
 184  * deadlock, the semaphore is only acquired or released in the outermost call.
 185  *
 186  * This function allocates a nilfs_transaction_info struct to keep context
 187  * information on it.  It is initialized and hooked onto the current task in
 188  * the outermost call.  If a pre-allocated struct is given to @ti, it is used
 189  * instead; otherwise a new struct is assigned from a slab.
 190  *
 191  * When @vacancy_check flag is set, this function will check the amount of
 192  * free space, and will wait for the GC to reclaim disk space if low capacity.
 193  *
 194  * Return Value: On success, 0 is returned. On error, one of the following
 195  * negative error code is returned.
 196  *
 197  * %-ENOMEM - Insufficient memory available.
 198  *
 199  * %-ENOSPC - No space left on device
 200  */
 201 int nilfs_transaction_begin(struct super_block *sb,
 202                             struct nilfs_transaction_info *ti,
 203                             int vacancy_check)
 204 {
 205         struct the_nilfs *nilfs;
 206         int ret = nilfs_prepare_segment_lock(sb, ti);
 207         struct nilfs_transaction_info *trace_ti;
 208
 209         if (unlikely(ret < 0))
 210                 return ret;
 211         if (ret > 0) {
 212                 trace_ti = current->journal_info;
 213
 214                 trace_nilfs2_transaction_transition(sb, trace_ti,
 215                                     trace_ti->ti_count, trace_ti->ti_flags,
 216                                     TRACE_NILFS2_TRANSACTION_BEGIN);
 217                 return 0;
 218         }
 219
 220         sb_start_intwrite(sb);
 221
 222         nilfs = sb->s_fs_info;
 223         down_read(&nilfs->ns_segctor_sem);
 224         if (vacancy_check && nilfs_near_disk_full(nilfs)) {
 225                 up_read(&nilfs->ns_segctor_sem);
 226                 ret = -ENOSPC;
 227                 goto failed;
 228         }
 229
 230         trace_ti = current->journal_info;
 231         trace_nilfs2_transaction_transition(sb, trace_ti, trace_ti->ti_count,
 232                                             trace_ti->ti_flags,
 233                                             TRACE_NILFS2_TRANSACTION_BEGIN);
 234         return 0;
 235
 236  failed:
 237         ti = current->journal_info;
 238         current->journal_info = ti->ti_save;
 239         if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 240                 kmem_cache_free(nilfs_transaction_cachep, ti);
 241         sb_end_intwrite(sb);
 242         return ret;
 243 }
 244
 245 /**
 246  * nilfs_transaction_commit - commit indivisible file operations.
 247  * @sb: super block
 248  *
 249  * nilfs_transaction_commit() releases the read semaphore which is
 250  * acquired by nilfs_transaction_begin(). This is only performed
 251  * in outermost call of this function.  If a commit flag is set,
 252  * nilfs_transaction_commit() sets a timer to start the segment
 253  * constructor.  If a sync flag is set, it starts construction
 254  * directly.
 255  */
 256 int nilfs_transaction_commit(struct super_block *sb)
 257 {
 258         struct nilfs_transaction_info *ti = current->journal_info;
 259         struct the_nilfs *nilfs = sb->s_fs_info;
 260         int err = 0;
 261
 262         BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 263         ti->ti_flags |= NILFS_TI_COMMIT;
 264         if (ti->ti_count > 0) {
 265                 ti->ti_count--;
 266                 trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 267                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
 268                 return 0;
 269         }
 270         if (nilfs->ns_writer) {
 271                 struct nilfs_sc_info *sci = nilfs->ns_writer;
 272
 273                 if (ti->ti_flags & NILFS_TI_COMMIT)
 274                         nilfs_segctor_start_timer(sci);
 275                 if (atomic_read(&nilfs->ns_ndirtyblks) > sci->sc_watermark)
 276                         nilfs_segctor_do_flush(sci, 0);
 277         }
 278         up_read(&nilfs->ns_segctor_sem);
 279         trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 280                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
 281
 282         current->journal_info = ti->ti_save;
 283
 284         if (ti->ti_flags & NILFS_TI_SYNC)
 285                 err = nilfs_construct_segment(sb);
 286         if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 287                 kmem_cache_free(nilfs_transaction_cachep, ti);
 288         sb_end_intwrite(sb);
 289         return err;
 290 }
 291
 292 void nilfs_transaction_abort(struct super_block *sb)
 293 {
 294         struct nilfs_transaction_info *ti = current->journal_info;
 295         struct the_nilfs *nilfs = sb->s_fs_info;
 296
 297         BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 298         if (ti->ti_count > 0) {
 299                 ti->ti_count--;
 300                 trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 301                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
 302                 return;
 303         }
 304         up_read(&nilfs->ns_segctor_sem);
 305
 306         trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 307                     ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
 308
 309         current->journal_info = ti->ti_save;
 310         if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 311                 kmem_cache_free(nilfs_transaction_cachep, ti);
 312         sb_end_intwrite(sb);
 313 }
 314
 315 void nilfs_relax_pressure_in_lock(struct super_block *sb)
 316 {
 317         struct the_nilfs *nilfs = sb->s_fs_info;
 318         struct nilfs_sc_info *sci = nilfs->ns_writer;
 319
 320         if (!sci || !sci->sc_flush_request)
 321                 return;
 322
 323         set_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
 324         up_read(&nilfs->ns_segctor_sem);
 325
 326         down_write(&nilfs->ns_segctor_sem);
 327         if (sci->sc_flush_request &&
 328             test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags)) {
 329                 struct nilfs_transaction_info *ti = current->journal_info;
 330
 331                 ti->ti_flags |= NILFS_TI_WRITER;
 332                 nilfs_segctor_do_immediate_flush(sci);
 333                 ti->ti_flags &= ~NILFS_TI_WRITER;
 334         }
 335         downgrade_write(&nilfs->ns_segctor_sem);
 336 }
 337
 338 static void nilfs_transaction_lock(struct super_block *sb,
 339                                    struct nilfs_transaction_info *ti,
 340                                    int gcflag)
 341 {
 342         struct nilfs_transaction_info *cur_ti = current->journal_info;
 343         struct the_nilfs *nilfs = sb->s_fs_info;
 344         struct nilfs_sc_info *sci = nilfs->ns_writer;
 345
 346         WARN_ON(cur_ti);
 347         ti->ti_flags = NILFS_TI_WRITER;
 348         ti->ti_count = 0;
 349         ti->ti_save = cur_ti;
 350         ti->ti_magic = NILFS_TI_MAGIC;
 351         current->journal_info = ti;
 352
 353         for (;;) {
 354                 trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 355                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_TRYLOCK);
 356
 357                 down_write(&nilfs->ns_segctor_sem);
 358                 if (!test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags))
 359                         break;
 360
 361                 nilfs_segctor_do_immediate_flush(sci);
 362
 363                 up_write(&nilfs->ns_segctor_sem);
 364                 cond_resched();
 365         }
 366         if (gcflag)
 367                 ti->ti_flags |= NILFS_TI_GC;
 368
 369         trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 370                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_LOCK);
 371 }
 372
 373 static void nilfs_transaction_unlock(struct super_block *sb)
 374 {
 375         struct nilfs_transaction_info *ti = current->journal_info;
 376         struct the_nilfs *nilfs = sb->s_fs_info;
 377
 378         BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 379         BUG_ON(ti->ti_count > 0);
 380
 381         up_write(&nilfs->ns_segctor_sem);
 382         current->journal_info = ti->ti_save;
 383
 384         trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 385                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_UNLOCK);
 386 }
 387
 388 static void *nilfs_segctor_map_segsum_entry(struct nilfs_sc_info *sci,
 389                                             struct nilfs_segsum_pointer *ssp,
 390                                             unsigned int bytes)
 391 {
 392         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 393         unsigned int blocksize = sci->sc_super->s_blocksize;
 394         void *p;
 395
 396         if (unlikely(ssp->offset + bytes > blocksize)) {
 397                 ssp->offset = 0;
 398                 BUG_ON(NILFS_SEGBUF_BH_IS_LAST(ssp->bh,
 399                                                &segbuf->sb_segsum_buffers));
 400                 ssp->bh = NILFS_SEGBUF_NEXT_BH(ssp->bh);
 401         }
 402         p = ssp->bh->b_data + ssp->offset;
 403         ssp->offset += bytes;
 404         return p;
 405 }
 406
 407 /**
 408  * nilfs_segctor_reset_segment_buffer - reset the current segment buffer
 409  * @sci: nilfs_sc_info
 410  */
 411 static int nilfs_segctor_reset_segment_buffer(struct nilfs_sc_info *sci)
 412 {
 413         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 414         struct buffer_head *sumbh;
 415         unsigned int sumbytes;
 416         unsigned int flags = 0;
 417         int err;
 418
 419         if (nilfs_doing_gc())
 420                 flags = NILFS_SS_GC;
 421         err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime, sci->sc_cno);
 422         if (unlikely(err))
 423                 return err;
 424
 425         sumbh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
 426         sumbytes = segbuf->sb_sum.sumbytes;
 427         sci->sc_finfo_ptr.bh = sumbh;  sci->sc_finfo_ptr.offset = sumbytes;
 428         sci->sc_binfo_ptr.bh = sumbh;  sci->sc_binfo_ptr.offset = sumbytes;
 429         sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 430         return 0;
 431 }
 432
 433 static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
 434 {
 435         sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
 436         if (NILFS_SEGBUF_IS_LAST(sci->sc_curseg, &sci->sc_segbufs))
 437                 return -E2BIG; /*
 438                                 * The current segment is filled up
 439                                 * (internal code)
 440                                 */
 441         sci->sc_curseg = NILFS_NEXT_SEGBUF(sci->sc_curseg);
 442         return nilfs_segctor_reset_segment_buffer(sci);
 443 }
 444
 445 static int nilfs_segctor_add_super_root(struct nilfs_sc_info *sci)
 446 {
 447         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 448         int err;
 449
 450         if (segbuf->sb_sum.nblocks >= segbuf->sb_rest_blocks) {
 451                 err = nilfs_segctor_feed_segment(sci);
 452                 if (err)
 453                         return err;
 454                 segbuf = sci->sc_curseg;
 455         }
 456         err = nilfs_segbuf_extend_payload(segbuf, &segbuf->sb_super_root);
 457         if (likely(!err))
 458                 segbuf->sb_sum.flags |= NILFS_SS_SR;
 459         return err;
 460 }
 461
 462 /*
 463  * Functions for making segment summary and payloads
 464  */
 465 static int nilfs_segctor_segsum_block_required(
 466         struct nilfs_sc_info *sci, const struct nilfs_segsum_pointer *ssp,
 467         unsigned int binfo_size)
 468 {
 469         unsigned int blocksize = sci->sc_super->s_blocksize;
 470         /* Size of finfo and binfo is enough small against blocksize */
 471
 472         return ssp->offset + binfo_size +
 473                 (!sci->sc_blk_cnt ? sizeof(struct nilfs_finfo) : 0) >
 474                 blocksize;
 475 }
 476
 477 static void nilfs_segctor_begin_finfo(struct nilfs_sc_info *sci,
 478                                       struct inode *inode)
 479 {
 480         sci->sc_curseg->sb_sum.nfinfo++;
 481         sci->sc_binfo_ptr = sci->sc_finfo_ptr;
 482         nilfs_segctor_map_segsum_entry(
 483                 sci, &sci->sc_binfo_ptr, sizeof(struct nilfs_finfo));
 484
 485         if (NILFS_I(inode)->i_root &&
 486             !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 487                 set_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
 488         /* skip finfo */
 489 }
 490
 491 static void nilfs_segctor_end_finfo(struct nilfs_sc_info *sci,
 492                                     struct inode *inode)
 493 {
 494         struct nilfs_finfo *finfo;
 495         struct nilfs_inode_info *ii;
 496         struct nilfs_segment_buffer *segbuf;
 497         __u64 cno;
 498
 499         if (sci->sc_blk_cnt == 0)
 500                 return;
 501
 502         ii = NILFS_I(inode);
 503
 504         if (test_bit(NILFS_I_GCINODE, &ii->i_state))
 505                 cno = ii->i_cno;
 506         else if (NILFS_ROOT_METADATA_FILE(inode->i_ino))
 507                 cno = 0;
 508         else
 509                 cno = sci->sc_cno;
 510
 511         finfo = nilfs_segctor_map_segsum_entry(sci, &sci->sc_finfo_ptr,
 512                                                  sizeof(*finfo));
 513         finfo->fi_ino = cpu_to_le64(inode->i_ino);
 514         finfo->fi_nblocks = cpu_to_le32(sci->sc_blk_cnt);
 515         finfo->fi_ndatablk = cpu_to_le32(sci->sc_datablk_cnt);
 516         finfo->fi_cno = cpu_to_le64(cno);
 517
 518         segbuf = sci->sc_curseg;
 519         segbuf->sb_sum.sumbytes = sci->sc_binfo_ptr.offset +
 520                 sci->sc_super->s_blocksize * (segbuf->sb_sum.nsumblk - 1);
 521         sci->sc_finfo_ptr = sci->sc_binfo_ptr;
 522         sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 523 }
 524
 525 static int nilfs_segctor_add_file_block(struct nilfs_sc_info *sci,
 526                                         struct buffer_head *bh,
 527                                         struct inode *inode,
 528                                         unsigned int binfo_size)
 529 {
 530         struct nilfs_segment_buffer *segbuf;
 531         int required, err = 0;
 532
 533  retry:
 534         segbuf = sci->sc_curseg;
 535         required = nilfs_segctor_segsum_block_required(
 536                 sci, &sci->sc_binfo_ptr, binfo_size);
 537         if (segbuf->sb_sum.nblocks + required + 1 > segbuf->sb_rest_blocks) {
 538                 nilfs_segctor_end_finfo(sci, inode);
 539                 err = nilfs_segctor_feed_segment(sci);
 540                 if (err)
 541                         return err;
 542                 goto retry;
 543         }
 544         if (unlikely(required)) {
 545                 err = nilfs_segbuf_extend_segsum(segbuf);
 546                 if (unlikely(err))
 547                         goto failed;
 548         }
 549         if (sci->sc_blk_cnt == 0)
 550                 nilfs_segctor_begin_finfo(sci, inode);
 551
 552         nilfs_segctor_map_segsum_entry(sci, &sci->sc_binfo_ptr, binfo_size);
 553         /* Substitution to vblocknr is delayed until update_blocknr() */
 554         nilfs_segbuf_add_file_buffer(segbuf, bh);
 555         sci->sc_blk_cnt++;
 556  failed:
 557         return err;
 558 }
 559
 560 /*
 561  * Callback functions that enumerate, mark, and collect dirty blocks
 562  */
 563 static int nilfs_collect_file_data(struct nilfs_sc_info *sci,
 564                                    struct buffer_head *bh, struct inode *inode)
 565 {
 566         int err;
 567
 568         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 569         if (err < 0)
 570                 return err;
 571
 572         err = nilfs_segctor_add_file_block(sci, bh, inode,
 573                                            sizeof(struct nilfs_binfo_v));
 574         if (!err)
 575                 sci->sc_datablk_cnt++;
 576         return err;
 577 }
 578
 579 static int nilfs_collect_file_node(struct nilfs_sc_info *sci,
 580                                    struct buffer_head *bh,
 581                                    struct inode *inode)
 582 {
 583         return nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 584 }
 585
 586 static int nilfs_collect_file_bmap(struct nilfs_sc_info *sci,
 587                                    struct buffer_head *bh,
 588                                    struct inode *inode)
 589 {
 590         WARN_ON(!buffer_dirty(bh));
 591         return nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 592 }
 593
 594 static void nilfs_write_file_data_binfo(struct nilfs_sc_info *sci,
 595                                         struct nilfs_segsum_pointer *ssp,
 596                                         union nilfs_binfo *binfo)
 597 {
 598         struct nilfs_binfo_v *binfo_v = nilfs_segctor_map_segsum_entry(
 599                 sci, ssp, sizeof(*binfo_v));
 600         *binfo_v = binfo->bi_v;
 601 }
 602
 603 static void nilfs_write_file_node_binfo(struct nilfs_sc_info *sci,
 604                                         struct nilfs_segsum_pointer *ssp,
 605                                         union nilfs_binfo *binfo)
 606 {
 607         __le64 *vblocknr = nilfs_segctor_map_segsum_entry(
 608                 sci, ssp, sizeof(*vblocknr));
 609         *vblocknr = binfo->bi_v.bi_vblocknr;
 610 }
 611
 612 static const struct nilfs_sc_operations nilfs_sc_file_ops = {
 613         .collect_data = nilfs_collect_file_data,
 614         .collect_node = nilfs_collect_file_node,
 615         .collect_bmap = nilfs_collect_file_bmap,
 616         .write_data_binfo = nilfs_write_file_data_binfo,
 617         .write_node_binfo = nilfs_write_file_node_binfo,
 618 };
 619
 620 static int nilfs_collect_dat_data(struct nilfs_sc_info *sci,
 621                                   struct buffer_head *bh, struct inode *inode)
 622 {
 623         int err;
 624
 625         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 626         if (err < 0)
 627                 return err;
 628
 629         err = nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 630         if (!err)
 631                 sci->sc_datablk_cnt++;
 632         return err;
 633 }
 634
 635 static int nilfs_collect_dat_bmap(struct nilfs_sc_info *sci,
 636                                   struct buffer_head *bh, struct inode *inode)
 637 {
 638         WARN_ON(!buffer_dirty(bh));
 639         return nilfs_segctor_add_file_block(sci, bh, inode,
 640                                             sizeof(struct nilfs_binfo_dat));
 641 }
 642
 643 static void nilfs_write_dat_data_binfo(struct nilfs_sc_info *sci,
 644                                        struct nilfs_segsum_pointer *ssp,
 645                                        union nilfs_binfo *binfo)
 646 {
 647         __le64 *blkoff = nilfs_segctor_map_segsum_entry(sci, ssp,
 648                                                           sizeof(*blkoff));
 649         *blkoff = binfo->bi_dat.bi_blkoff;
 650 }
 651
 652 static void nilfs_write_dat_node_binfo(struct nilfs_sc_info *sci,
 653                                        struct nilfs_segsum_pointer *ssp,
 654                                        union nilfs_binfo *binfo)
 655 {
 656         struct nilfs_binfo_dat *binfo_dat =
 657                 nilfs_segctor_map_segsum_entry(sci, ssp, sizeof(*binfo_dat));
 658         *binfo_dat = binfo->bi_dat;
 659 }
 660
 661 static const struct nilfs_sc_operations nilfs_sc_dat_ops = {
 662         .collect_data = nilfs_collect_dat_data,
 663         .collect_node = nilfs_collect_file_node,
 664         .collect_bmap = nilfs_collect_dat_bmap,
 665         .write_data_binfo = nilfs_write_dat_data_binfo,
 666         .write_node_binfo = nilfs_write_dat_node_binfo,
 667 };
 668
 669 static const struct nilfs_sc_operations nilfs_sc_dsync_ops = {
 670         .collect_data = nilfs_collect_file_data,
 671         .collect_node = NULL,
 672         .collect_bmap = NULL,
 673         .write_data_binfo = nilfs_write_file_data_binfo,
 674         .write_node_binfo = NULL,
 675 };
 676
 677 static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode,
 678                                               struct list_head *listp,
 679                                               size_t nlimit,
 680                                               loff_t start, loff_t end)
 681 {
 682         struct address_space *mapping = inode->i_mapping;
 683         struct pagevec pvec;
 684         pgoff_t index = 0, last = ULONG_MAX;
 685         size_t ndirties = 0;
 686         int i;
 687
 688         if (unlikely(start != 0 || end != LLONG_MAX)) {
 689                 /*
 690                  * A valid range is given for sync-ing data pages. The
 691                  * range is rounded to per-page; extra dirty buffers
 692                  * may be included if blocksize < pagesize.
 693                  */
 694                 index = start >> PAGE_SHIFT;
 695                 last = end >> PAGE_SHIFT;
 696         }
 697         pagevec_init(&pvec);
 698  repeat:
 699         if (unlikely(index > last) ||
 700             !pagevec_lookup_range_tag(&pvec, mapping, &index, last,
 701                                 PAGECACHE_TAG_DIRTY))
 702                 return ndirties;
 703
 704         for (i = 0; i < pagevec_count(&pvec); i++) {
 705                 struct buffer_head *bh, *head;
 706                 struct page *page = pvec.pages[i];
 707
 708                 lock_page(page);
 709                 if (!page_has_buffers(page))
 710                         create_empty_buffers(page, i_blocksize(inode), 0);
 711                 unlock_page(page);
 712
 713                 bh = head = page_buffers(page);
 714                 do {
 715                         if (!buffer_dirty(bh) || buffer_async_write(bh))
 716                                 continue;
 717                         get_bh(bh);
 718                         list_add_tail(&bh->b_assoc_buffers, listp);
 719                         ndirties++;
 720                         if (unlikely(ndirties >= nlimit)) {
 721                                 pagevec_release(&pvec);
 722                                 cond_resched();
 723                                 return ndirties;
 724                         }
 725                 } while (bh = bh->b_this_page, bh != head);
 726         }
 727         pagevec_release(&pvec);
 728         cond_resched();
 729         goto repeat;
 730 }
 731
 732 static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
 733                                             struct list_head *listp)
 734 {
 735         struct nilfs_inode_info *ii = NILFS_I(inode);
 736         struct inode *btnc_inode = ii->i_assoc_inode;
 737         struct pagevec pvec;
 738         struct buffer_head *bh, *head;
 739         unsigned int i;
 740         pgoff_t index = 0;
 741
 742         if (!btnc_inode)
 743                 return;
 744
 745         pagevec_init(&pvec);
 746
 747         while (pagevec_lookup_tag(&pvec, btnc_inode->i_mapping, &index,
 748                                         PAGECACHE_TAG_DIRTY)) {
 749                 for (i = 0; i < pagevec_count(&pvec); i++) {
 750                         bh = head = page_buffers(pvec.pages[i]);
 751                         do {
 752                                 if (buffer_dirty(bh) &&
 753                                                 !buffer_async_write(bh)) {
 754                                         get_bh(bh);
 755                                         list_add_tail(&bh->b_assoc_buffers,
 756                                                       listp);
 757                                 }
 758                                 bh = bh->b_this_page;
 759                         } while (bh != head);
 760                 }
 761                 pagevec_release(&pvec);
 762                 cond_resched();
 763         }
 764 }
 765
 766 static void nilfs_dispose_list(struct the_nilfs *nilfs,
 767                                struct list_head *head, int force)
 768 {
 769         struct nilfs_inode_info *ii, *n;
 770         struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
 771         unsigned int nv = 0;
 772
 773         while (!list_empty(head)) {
 774                 spin_lock(&nilfs->ns_inode_lock);
 775                 list_for_each_entry_safe(ii, n, head, i_dirty) {
 776                         list_del_init(&ii->i_dirty);
 777                         if (force) {
 778                                 if (unlikely(ii->i_bh)) {
 779                                         brelse(ii->i_bh);
 780                                         ii->i_bh = NULL;
 781                                 }
 782                         } else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
 783                                 set_bit(NILFS_I_QUEUED, &ii->i_state);
 784                                 list_add_tail(&ii->i_dirty,
 785                                               &nilfs->ns_dirty_files);
 786                                 continue;
 787                         }
 788                         ivec[nv++] = ii;
 789                         if (nv == SC_N_INODEVEC)
 790                                 break;
 791                 }
 792                 spin_unlock(&nilfs->ns_inode_lock);
 793
 794                 for (pii = ivec; nv > 0; pii++, nv--)
 795                         iput(&(*pii)->vfs_inode);
 796         }
 797 }
 798
 799 static void nilfs_iput_work_func(struct work_struct *work)
 800 {
 801         struct nilfs_sc_info *sci = container_of(work, struct nilfs_sc_info,
 802                                                  sc_iput_work);
 803         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 804
 805         nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 0);
 806 }
 807
 808 static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
 809                                      struct nilfs_root *root)
 810 {
 811         int ret = 0;
 812
 813         if (nilfs_mdt_fetch_dirty(root->ifile))
 814                 ret++;
 815         if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
 816                 ret++;
 817         if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
 818                 ret++;
 819         if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
 820                 ret++;
 821         return ret;
 822 }
 823
 824 static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 825 {
 826         return list_empty(&sci->sc_dirty_files) &&
 827                 !test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
 828                 sci->sc_nfreesegs == 0 &&
 829                 (!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
 830 }
 831
 832 static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 833 {
 834         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 835         int ret = 0;
 836
 837         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
 838                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
 839
 840         spin_lock(&nilfs->ns_inode_lock);
 841         if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
 842                 ret++;
 843
 844         spin_unlock(&nilfs->ns_inode_lock);
 845         return ret;
 846 }
 847
 848 static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 849 {
 850         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 851
 852         nilfs_mdt_clear_dirty(sci->sc_root->ifile);
 853         nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
 854         nilfs_mdt_clear_dirty(nilfs->ns_sufile);
 855         nilfs_mdt_clear_dirty(nilfs->ns_dat);
 856 }
 857
 858 static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
 859 {
 860         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 861         struct buffer_head *bh_cp;
 862         struct nilfs_checkpoint *raw_cp;
 863         int err;
 864
 865         /* XXX: this interface will be changed */
 866         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 1,
 867                                           &raw_cp, &bh_cp);
 868         if (likely(!err)) {
 869                 /*
 870                  * The following code is duplicated with cpfile.  But, it is
 871                  * needed to collect the checkpoint even if it was not newly
 872                  * created.
 873                  */
 874                 mark_buffer_dirty(bh_cp);
 875                 nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
 876                 nilfs_cpfile_put_checkpoint(
 877                         nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 878         } else
 879                 WARN_ON(err == -EINVAL || err == -ENOENT);
 880
 881         return err;
 882 }
 883
 884 static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
 885 {
 886         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 887         struct buffer_head *bh_cp;
 888         struct nilfs_checkpoint *raw_cp;
 889         int err;
 890
 891         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
 892                                           &raw_cp, &bh_cp);
 893         if (unlikely(err)) {
 894                 WARN_ON(err == -EINVAL || err == -ENOENT);
 895                 goto failed_ibh;
 896         }
 897         raw_cp->cp_snapshot_list.ssl_next = 0;
 898         raw_cp->cp_snapshot_list.ssl_prev = 0;
 899         raw_cp->cp_inodes_count =
 900                 cpu_to_le64(atomic64_read(&sci->sc_root->inodes_count));
 901         raw_cp->cp_blocks_count =
 902                 cpu_to_le64(atomic64_read(&sci->sc_root->blocks_count));
 903         raw_cp->cp_nblk_inc =
 904                 cpu_to_le64(sci->sc_nblk_inc + sci->sc_nblk_this_inc);
 905         raw_cp->cp_create = cpu_to_le64(sci->sc_seg_ctime);
 906         raw_cp->cp_cno = cpu_to_le64(nilfs->ns_cno);
 907
 908         if (test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 909                 nilfs_checkpoint_clear_minor(raw_cp);
 910         else
 911                 nilfs_checkpoint_set_minor(raw_cp);
 912
 913         nilfs_write_inode_common(sci->sc_root->ifile,
 914                                  &raw_cp->cp_ifile_inode, 1);
 915         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 916         return 0;
 917
 918  failed_ibh:
 919         return err;
 920 }
 921
 922 static void nilfs_fill_in_file_bmap(struct inode *ifile,
 923                                     struct nilfs_inode_info *ii)
 924
 925 {
 926         struct buffer_head *ibh;
 927         struct nilfs_inode *raw_inode;
 928
 929         if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
 930                 ibh = ii->i_bh;
 931                 BUG_ON(!ibh);
 932                 raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
 933                                                   ibh);
 934                 nilfs_bmap_write(ii->i_bmap, raw_inode);
 935                 nilfs_ifile_unmap_inode(ifile, ii->vfs_inode.i_ino, ibh);
 936         }
 937 }
 938
 939 static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
 940 {
 941         struct nilfs_inode_info *ii;
 942
 943         list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
 944                 nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
 945                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
 946         }
 947 }
 948
 949 static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 950                                              struct the_nilfs *nilfs)
 951 {
 952         struct buffer_head *bh_sr;
 953         struct nilfs_super_root *raw_sr;
 954         unsigned int isz, srsz;
 955
 956         bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
 957         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 958         isz = nilfs->ns_inode_size;
 959         srsz = NILFS_SR_BYTES(isz);
 960
 961         raw_sr->sr_bytes = cpu_to_le16(srsz);
 962         raw_sr->sr_nongc_ctime
 963                 = cpu_to_le64(nilfs_doing_gc() ?
 964                               nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
 965         raw_sr->sr_flags = 0;
 966
 967         nilfs_write_inode_common(nilfs->ns_dat, (void *)raw_sr +
 968                                  NILFS_SR_DAT_OFFSET(isz), 1);
 969         nilfs_write_inode_common(nilfs->ns_cpfile, (void *)raw_sr +
 970                                  NILFS_SR_CPFILE_OFFSET(isz), 1);
 971         nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
 972                                  NILFS_SR_SUFILE_OFFSET(isz), 1);
 973         memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
 974 }
 975
 976 static void nilfs_redirty_inodes(struct list_head *head)
 977 {
 978         struct nilfs_inode_info *ii;
 979
 980         list_for_each_entry(ii, head, i_dirty) {
 981                 if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
 982                         clear_bit(NILFS_I_COLLECTED, &ii->i_state);
 983         }
 984 }
 985
 986 static void nilfs_drop_collected_inodes(struct list_head *head)
 987 {
 988         struct nilfs_inode_info *ii;
 989
 990         list_for_each_entry(ii, head, i_dirty) {
 991                 if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
 992                         continue;
 993
 994                 clear_bit(NILFS_I_INODE_SYNC, &ii->i_state);
 995                 set_bit(NILFS_I_UPDATED, &ii->i_state);
 996         }
 997 }
 998
 999 static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
1000                                        struct inode *inode,
1001                                        struct list_head *listp,
1002                                        int (*collect)(struct nilfs_sc_info *,
1003                                                       struct buffer_head *,
1004                                                       struct inode *))
1005 {
1006         struct buffer_head *bh, *n;
1007         int err = 0;
1008
1009         if (collect) {
1010                 list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
1011                         list_del_init(&bh->b_assoc_buffers);
1012                         err = collect(sci, bh, inode);
1013                         brelse(bh);
1014                         if (unlikely(err))
1015                                 goto dispose_buffers;
1016                 }
1017                 return 0;
1018         }
1019
1020  dispose_buffers:
1021         while (!list_empty(listp)) {
1022                 bh = list_first_entry(listp, struct buffer_head,
1023                                       b_assoc_buffers);
1024                 list_del_init(&bh->b_assoc_buffers);
1025                 brelse(bh);
1026         }
1027         return err;
1028 }
1029
1030 static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
1031 {
1032         /* Remaining number of blocks within segment buffer */
1033         return sci->sc_segbuf_nblocks -
1034                 (sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
1035 }
1036
1037 static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
1038                                    struct inode *inode,
1039                                    const struct nilfs_sc_operations *sc_ops)
1040 {
1041         LIST_HEAD(data_buffers);
1042         LIST_HEAD(node_buffers);
1043         int err;
1044
1045         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1046                 size_t n, rest = nilfs_segctor_buffer_rest(sci);
1047
1048                 n = nilfs_lookup_dirty_data_buffers(
1049                         inode, &data_buffers, rest + 1, 0, LLONG_MAX);
1050                 if (n > rest) {
1051                         err = nilfs_segctor_apply_buffers(
1052                                 sci, inode, &data_buffers,
1053                                 sc_ops->collect_data);
1054                         BUG_ON(!err); /* always receive -E2BIG or true error */
1055                         goto break_or_fail;
1056                 }
1057         }
1058         nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
1059
1060         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1061                 err = nilfs_segctor_apply_buffers(
1062                         sci, inode, &data_buffers, sc_ops->collect_data);
1063                 if (unlikely(err)) {
1064                         /* dispose node list */
1065                         nilfs_segctor_apply_buffers(
1066                                 sci, inode, &node_buffers, NULL);
1067                         goto break_or_fail;
1068                 }
1069                 sci->sc_stage.flags |= NILFS_CF_NODE;
1070         }
1071         /* Collect node */
1072         err = nilfs_segctor_apply_buffers(
1073                 sci, inode, &node_buffers, sc_ops->collect_node);
1074         if (unlikely(err))
1075                 goto break_or_fail;
1076
1077         nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1078         err = nilfs_segctor_apply_buffers(
1079                 sci, inode, &node_buffers, sc_ops->collect_bmap);
1080         if (unlikely(err))
1081                 goto break_or_fail;
1082
1083         nilfs_segctor_end_finfo(sci, inode);
1084         sci->sc_stage.flags &= ~NILFS_CF_NODE;
1085
1086  break_or_fail:
1087         return err;
1088 }
1089
1090 static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1091                                          struct inode *inode)
1092 {
1093         LIST_HEAD(data_buffers);
1094         size_t n, rest = nilfs_segctor_buffer_rest(sci);
1095         int err;
1096
1097         n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1098                                             sci->sc_dsync_start,
1099                                             sci->sc_dsync_end);
1100
1101         err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1102                                           nilfs_collect_file_data);
1103         if (!err) {
1104                 nilfs_segctor_end_finfo(sci, inode);
1105                 BUG_ON(n > rest);
1106                 /* always receive -E2BIG or true error if n > rest */
1107         }
1108         return err;
1109 }
1110
1111 static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1112 {
1113         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1114         struct list_head *head;
1115         struct nilfs_inode_info *ii;
1116         size_t ndone;
1117         int err = 0;
1118
1119         switch (nilfs_sc_cstage_get(sci)) {
1120         case NILFS_ST_INIT:
1121                 /* Pre-processes */
1122                 sci->sc_stage.flags = 0;
1123
1124                 if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1125                         sci->sc_nblk_inc = 0;
1126                         sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1127                         if (mode == SC_LSEG_DSYNC) {
1128                                 nilfs_sc_cstage_set(sci, NILFS_ST_DSYNC);
1129                                 goto dsync_mode;
1130                         }
1131                 }
1132
1133                 sci->sc_stage.dirty_file_ptr = NULL;
1134                 sci->sc_stage.gc_inode_ptr = NULL;
1135                 if (mode == SC_FLUSH_DAT) {
1136                         nilfs_sc_cstage_set(sci, NILFS_ST_DAT);
1137                         goto dat_stage;
1138                 }
1139                 nilfs_sc_cstage_inc(sci);
1140                 fallthrough;
1141         case NILFS_ST_GC:
1142                 if (nilfs_doing_gc()) {
1143                         head = &sci->sc_gc_inodes;
1144                         ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1145                                                 head, i_dirty);
1146                         list_for_each_entry_continue(ii, head, i_dirty) {
1147                                 err = nilfs_segctor_scan_file(
1148                                         sci, &ii->vfs_inode,
1149                                         &nilfs_sc_file_ops);
1150                                 if (unlikely(err)) {
1151                                         sci->sc_stage.gc_inode_ptr = list_entry(
1152                                                 ii->i_dirty.prev,
1153                                                 struct nilfs_inode_info,
1154                                                 i_dirty);
1155                                         goto break_or_fail;
1156                                 }
1157                                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
1158                         }
1159                         sci->sc_stage.gc_inode_ptr = NULL;
1160                 }
1161                 nilfs_sc_cstage_inc(sci);
1162                 fallthrough;
1163         case NILFS_ST_FILE:
1164                 head = &sci->sc_dirty_files;
1165                 ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1166                                         i_dirty);
1167                 list_for_each_entry_continue(ii, head, i_dirty) {
1168                         clear_bit(NILFS_I_DIRTY, &ii->i_state);
1169
1170                         err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1171                                                       &nilfs_sc_file_ops);
1172                         if (unlikely(err)) {
1173                                 sci->sc_stage.dirty_file_ptr =
1174                                         list_entry(ii->i_dirty.prev,
1175                                                    struct nilfs_inode_info,
1176                                                    i_dirty);
1177                                 goto break_or_fail;
1178                         }
1179                         /* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1180                         /* XXX: required ? */
1181                 }
1182                 sci->sc_stage.dirty_file_ptr = NULL;
1183                 if (mode == SC_FLUSH_FILE) {
1184                         nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1185                         return 0;
1186                 }
1187                 nilfs_sc_cstage_inc(sci);
1188                 sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1189                 fallthrough;
1190         case NILFS_ST_IFILE:
1191                 err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1192                                               &nilfs_sc_file_ops);
1193                 if (unlikely(err))
1194                         break;
1195                 nilfs_sc_cstage_inc(sci);
1196                 /* Creating a checkpoint */
1197                 err = nilfs_segctor_create_checkpoint(sci);
1198                 if (unlikely(err))
1199                         break;
1200                 fallthrough;
1201         case NILFS_ST_CPFILE:
1202                 err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1203                                               &nilfs_sc_file_ops);
1204                 if (unlikely(err))
1205                         break;
1206                 nilfs_sc_cstage_inc(sci);
1207                 fallthrough;
1208         case NILFS_ST_SUFILE:
1209                 err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1210                                          sci->sc_nfreesegs, &ndone);
1211                 if (unlikely(err)) {
1212                         nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1213                                                   sci->sc_freesegs, ndone,
1214                                                   NULL);
1215                         break;
1216                 }
1217                 sci->sc_stage.flags |= NILFS_CF_SUFREED;
1218
1219                 err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1220                                               &nilfs_sc_file_ops);
1221                 if (unlikely(err))
1222                         break;
1223                 nilfs_sc_cstage_inc(sci);
1224                 fallthrough;
1225         case NILFS_ST_DAT:
1226  dat_stage:
1227                 err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1228                                               &nilfs_sc_dat_ops);
1229                 if (unlikely(err))
1230                         break;
1231                 if (mode == SC_FLUSH_DAT) {
1232                         nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1233                         return 0;
1234                 }
1235                 nilfs_sc_cstage_inc(sci);
1236                 fallthrough;
1237         case NILFS_ST_SR:
1238                 if (mode == SC_LSEG_SR) {
1239                         /* Appending a super root */
1240                         err = nilfs_segctor_add_super_root(sci);
1241                         if (unlikely(err))
1242                                 break;
1243                 }
1244                 /* End of a logical segment */
1245                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1246                 nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1247                 return 0;
1248         case NILFS_ST_DSYNC:
1249  dsync_mode:
1250                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1251                 ii = sci->sc_dsync_inode;
1252                 if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1253                         break;
1254
1255                 err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1256                 if (unlikely(err))
1257                         break;
1258                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1259                 nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1260                 return 0;
1261         case NILFS_ST_DONE:
1262                 return 0;
1263         default:
1264                 BUG();
1265         }
1266
1267  break_or_fail:
1268         return err;
1269 }
1270
1271 /**
1272  * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1273  * @sci: nilfs_sc_info
1274  * @nilfs: nilfs object
1275  */
1276 static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1277                                             struct the_nilfs *nilfs)
1278 {
1279         struct nilfs_segment_buffer *segbuf, *prev;
1280         __u64 nextnum;
1281         int err, alloc = 0;
1282
1283         segbuf = nilfs_segbuf_new(sci->sc_super);
1284         if (unlikely(!segbuf))
1285                 return -ENOMEM;
1286
1287         if (list_empty(&sci->sc_write_logs)) {
1288                 nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1289                                  nilfs->ns_pseg_offset, nilfs);
1290                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1291                         nilfs_shift_to_next_segment(nilfs);
1292                         nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1293                 }
1294
1295                 segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1296                 nextnum = nilfs->ns_nextnum;
1297
1298                 if (nilfs->ns_segnum == nilfs->ns_nextnum)
1299                         /* Start from the head of a new full segment */
1300                         alloc++;
1301         } else {
1302                 /* Continue logs */
1303                 prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1304                 nilfs_segbuf_map_cont(segbuf, prev);
1305                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1306                 nextnum = prev->sb_nextnum;
1307
1308                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1309                         nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1310                         segbuf->sb_sum.seg_seq++;
1311                         alloc++;
1312                 }
1313         }
1314
1315         err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1316         if (err)
1317                 goto failed;
1318
1319         if (alloc) {
1320                 err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1321                 if (err)
1322                         goto failed;
1323         }
1324         nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1325
1326         BUG_ON(!list_empty(&sci->sc_segbufs));
1327         list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1328         sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1329         return 0;
1330
1331  failed:
1332         nilfs_segbuf_free(segbuf);
1333         return err;
1334 }
1335
1336 static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1337                                          struct the_nilfs *nilfs, int nadd)
1338 {
1339         struct nilfs_segment_buffer *segbuf, *prev;
1340         struct inode *sufile = nilfs->ns_sufile;
1341         __u64 nextnextnum;
1342         LIST_HEAD(list);
1343         int err, ret, i;
1344
1345         prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1346         /*
1347          * Since the segment specified with nextnum might be allocated during
1348          * the previous construction, the buffer including its segusage may
1349          * not be dirty.  The following call ensures that the buffer is dirty
1350          * and will pin the buffer on memory until the sufile is written.
1351          */
1352         err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1353         if (unlikely(err))
1354                 return err;
1355
1356         for (i = 0; i < nadd; i++) {
1357                 /* extend segment info */
1358                 err = -ENOMEM;
1359                 segbuf = nilfs_segbuf_new(sci->sc_super);
1360                 if (unlikely(!segbuf))
1361                         goto failed;
1362
1363                 /* map this buffer to region of segment on-disk */
1364                 nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1365                 sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1366
1367                 /* allocate the next next full segment */
1368                 err = nilfs_sufile_alloc(sufile, &nextnextnum);
1369                 if (unlikely(err))
1370                         goto failed_segbuf;
1371
1372                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1373                 nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1374
1375                 list_add_tail(&segbuf->sb_list, &list);
1376                 prev = segbuf;
1377         }
1378         list_splice_tail(&list, &sci->sc_segbufs);
1379         return 0;
1380
1381  failed_segbuf:
1382         nilfs_segbuf_free(segbuf);
1383  failed:
1384         list_for_each_entry(segbuf, &list, sb_list) {
1385                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1386                 WARN_ON(ret); /* never fails */
1387         }
1388         nilfs_destroy_logs(&list);
1389         return err;
1390 }
1391
1392 static void nilfs_free_incomplete_logs(struct list_head *logs,
1393                                        struct the_nilfs *nilfs)
1394 {
1395         struct nilfs_segment_buffer *segbuf, *prev;
1396         struct inode *sufile = nilfs->ns_sufile;
1397         int ret;
1398
1399         segbuf = NILFS_FIRST_SEGBUF(logs);
1400         if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1401                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1402                 WARN_ON(ret); /* never fails */
1403         }
1404         if (atomic_read(&segbuf->sb_err)) {
1405                 /* Case 1: The first segment failed */
1406                 if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1407                         /*
1408                          * Case 1a:  Partial segment appended into an existing
1409                          * segment
1410                          */
1411                         nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1412                                                 segbuf->sb_fseg_end);
1413                 else /* Case 1b:  New full segment */
1414                         set_nilfs_discontinued(nilfs);
1415         }
1416
1417         prev = segbuf;
1418         list_for_each_entry_continue(segbuf, logs, sb_list) {
1419                 if (prev->sb_nextnum != segbuf->sb_nextnum) {
1420                         ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1421                         WARN_ON(ret); /* never fails */
1422                 }
1423                 if (atomic_read(&segbuf->sb_err) &&
1424                     segbuf->sb_segnum != nilfs->ns_nextnum)
1425                         /* Case 2: extended segment (!= next) failed */
1426                         nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1427                 prev = segbuf;
1428         }
1429 }
1430
1431 static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1432                                           struct inode *sufile)
1433 {
1434         struct nilfs_segment_buffer *segbuf;
1435         unsigned long live_blocks;
1436         int ret;
1437
1438         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1439                 live_blocks = segbuf->sb_sum.nblocks +
1440                         (segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1441                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1442                                                      live_blocks,
1443                                                      sci->sc_seg_ctime);
1444                 WARN_ON(ret); /* always succeed because the segusage is dirty */
1445         }
1446 }
1447
1448 static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1449 {
1450         struct nilfs_segment_buffer *segbuf;
1451         int ret;
1452
1453         segbuf = NILFS_FIRST_SEGBUF(logs);
1454         ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1455                                              segbuf->sb_pseg_start -
1456                                              segbuf->sb_fseg_start, 0);
1457         WARN_ON(ret); /* always succeed because the segusage is dirty */
1458
1459         list_for_each_entry_continue(segbuf, logs, sb_list) {
1460                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1461                                                      0, 0);
1462                 WARN_ON(ret); /* always succeed */
1463         }
1464 }
1465
1466 static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1467                                             struct nilfs_segment_buffer *last,
1468                                             struct inode *sufile)
1469 {
1470         struct nilfs_segment_buffer *segbuf = last;
1471         int ret;
1472
1473         list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1474                 sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1475                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1476                 WARN_ON(ret);
1477         }
1478         nilfs_truncate_logs(&sci->sc_segbufs, last);
1479 }
1480
1481
1482 static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1483                                  struct the_nilfs *nilfs, int mode)
1484 {
1485         struct nilfs_cstage prev_stage = sci->sc_stage;
1486         int err, nadd = 1;
1487
1488         /* Collection retry loop */
1489         for (;;) {
1490                 sci->sc_nblk_this_inc = 0;
1491                 sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1492
1493                 err = nilfs_segctor_reset_segment_buffer(sci);
1494                 if (unlikely(err))
1495                         goto failed;
1496
1497                 err = nilfs_segctor_collect_blocks(sci, mode);
1498                 sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1499                 if (!err)
1500                         break;
1501
1502                 if (unlikely(err != -E2BIG))
1503                         goto failed;
1504
1505                 /* The current segment is filled up */
1506                 if (mode != SC_LSEG_SR ||
1507                     nilfs_sc_cstage_get(sci) < NILFS_ST_CPFILE)
1508                         break;
1509
1510                 nilfs_clear_logs(&sci->sc_segbufs);
1511
1512                 if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1513                         err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1514                                                         sci->sc_freesegs,
1515                                                         sci->sc_nfreesegs,
1516                                                         NULL);
1517                         WARN_ON(err); /* do not happen */
1518                         sci->sc_stage.flags &= ~NILFS_CF_SUFREED;
1519                 }
1520
1521                 err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1522                 if (unlikely(err))
1523                         return err;
1524
1525                 nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1526                 sci->sc_stage = prev_stage;
1527         }
1528         nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1529         return 0;
1530
1531  failed:
1532         return err;
1533 }
1534
1535 static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1536                                       struct buffer_head *new_bh)
1537 {
1538         BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1539
1540         list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1541         /* The caller must release old_bh */
1542 }
1543
1544 static int
1545 nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1546                                      struct nilfs_segment_buffer *segbuf,
1547                                      int mode)
1548 {
1549         struct inode *inode = NULL;
1550         sector_t blocknr;
1551         unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1552         unsigned long nblocks = 0, ndatablk = 0;
1553         const struct nilfs_sc_operations *sc_op = NULL;
1554         struct nilfs_segsum_pointer ssp;
1555         struct nilfs_finfo *finfo = NULL;
1556         union nilfs_binfo binfo;
1557         struct buffer_head *bh, *bh_org;
1558         ino_t ino = 0;
1559         int err = 0;
1560
1561         if (!nfinfo)
1562                 goto out;
1563
1564         blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1565         ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1566         ssp.offset = sizeof(struct nilfs_segment_summary);
1567
1568         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1569                 if (bh == segbuf->sb_super_root)
1570                         break;
1571                 if (!finfo) {
1572                         finfo = nilfs_segctor_map_segsum_entry(
1573                                 sci, &ssp, sizeof(*finfo));
1574                         ino = le64_to_cpu(finfo->fi_ino);
1575                         nblocks = le32_to_cpu(finfo->fi_nblocks);
1576                         ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1577
1578                         inode = bh->b_page->mapping->host;
1579
1580                         if (mode == SC_LSEG_DSYNC)
1581                                 sc_op = &nilfs_sc_dsync_ops;
1582                         else if (ino == NILFS_DAT_INO)
1583                                 sc_op = &nilfs_sc_dat_ops;
1584                         else /* file blocks */
1585                                 sc_op = &nilfs_sc_file_ops;
1586                 }
1587                 bh_org = bh;
1588                 get_bh(bh_org);
1589                 err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1590                                         &binfo);
1591                 if (bh != bh_org)
1592                         nilfs_list_replace_buffer(bh_org, bh);
1593                 brelse(bh_org);
1594                 if (unlikely(err))
1595                         goto failed_bmap;
1596
1597                 if (ndatablk > 0)
1598                         sc_op->write_data_binfo(sci, &ssp, &binfo);
1599                 else
1600                         sc_op->write_node_binfo(sci, &ssp, &binfo);
1601
1602                 blocknr++;
1603                 if (--nblocks == 0) {
1604                         finfo = NULL;
1605                         if (--nfinfo == 0)
1606                                 break;
1607                 } else if (ndatablk > 0)
1608                         ndatablk--;
1609         }
1610  out:
1611         return 0;
1612
1613  failed_bmap:
1614         return err;
1615 }
1616
1617 static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1618 {
1619         struct nilfs_segment_buffer *segbuf;
1620         int err;
1621
1622         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1623                 err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1624                 if (unlikely(err))
1625                         return err;
1626                 nilfs_segbuf_fill_in_segsum(segbuf);
1627         }
1628         return 0;
1629 }
1630
1631 static void nilfs_begin_page_io(struct page *page)
1632 {
1633         if (!page || PageWriteback(page))
1634                 /*
1635                  * For split b-tree node pages, this function may be called
1636                  * twice.  We ignore the 2nd or later calls by this check.
1637                  */
1638                 return;
1639
1640         lock_page(page);
1641         clear_page_dirty_for_io(page);
1642         set_page_writeback(page);
1643         unlock_page(page);
1644 }
1645
1646 static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci)
1647 {
1648         struct nilfs_segment_buffer *segbuf;
1649         struct page *bd_page = NULL, *fs_page = NULL;
1650
1651         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1652                 struct buffer_head *bh;
1653
1654                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1655                                     b_assoc_buffers) {
1656                         if (bh->b_page != bd_page) {
1657                                 if (bd_page) {
1658                                         lock_page(bd_page);
1659                                         clear_page_dirty_for_io(bd_page);
1660                                         set_page_writeback(bd_page);
1661                                         unlock_page(bd_page);
1662                                 }
1663                                 bd_page = bh->b_page;
1664                         }
1665                 }
1666
1667                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1668                                     b_assoc_buffers) {
1669                         set_buffer_async_write(bh);
1670                         if (bh == segbuf->sb_super_root) {
1671                                 if (bh->b_page != bd_page) {
1672                                         lock_page(bd_page);
1673                                         clear_page_dirty_for_io(bd_page);
1674                                         set_page_writeback(bd_page);
1675                                         unlock_page(bd_page);
1676                                         bd_page = bh->b_page;
1677                                 }
1678                                 break;
1679                         }
1680                         if (bh->b_page != fs_page) {
1681                                 nilfs_begin_page_io(fs_page);
1682                                 fs_page = bh->b_page;
1683                         }
1684                 }
1685         }
1686         if (bd_page) {
1687                 lock_page(bd_page);
1688                 clear_page_dirty_for_io(bd_page);
1689                 set_page_writeback(bd_page);
1690                 unlock_page(bd_page);
1691         }
1692         nilfs_begin_page_io(fs_page);
1693 }
1694
1695 static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1696                                struct the_nilfs *nilfs)
1697 {
1698         int ret;
1699
1700         ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1701         list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1702         return ret;
1703 }
1704
1705 static void nilfs_end_page_io(struct page *page, int err)
1706 {
1707         if (!page)
1708                 return;
1709
1710         if (buffer_nilfs_node(page_buffers(page)) && !PageWriteback(page)) {
1711                 /*
1712                  * For b-tree node pages, this function may be called twice
1713                  * or more because they might be split in a segment.
1714                  */
1715                 if (PageDirty(page)) {
1716                         /*
1717                          * For pages holding split b-tree node buffers, dirty
1718                          * flag on the buffers may be cleared discretely.
1719                          * In that case, the page is once redirtied for
1720                          * remaining buffers, and it must be cancelled if
1721                          * all the buffers get cleaned later.
1722                          */
1723                         lock_page(page);
1724                         if (nilfs_page_buffers_clean(page))
1725                                 __nilfs_clear_page_dirty(page);
1726                         unlock_page(page);
1727                 }
1728                 return;
1729         }
1730
1731         if (!err) {
1732                 if (!nilfs_page_buffers_clean(page))
1733                         __set_page_dirty_nobuffers(page);
1734                 ClearPageError(page);
1735         } else {
1736                 __set_page_dirty_nobuffers(page);
1737                 SetPageError(page);
1738         }
1739
1740         end_page_writeback(page);
1741 }
1742
1743 static void nilfs_abort_logs(struct list_head *logs, int err)
1744 {
1745         struct nilfs_segment_buffer *segbuf;
1746         struct page *bd_page = NULL, *fs_page = NULL;
1747         struct buffer_head *bh;
1748
1749         if (list_empty(logs))
1750                 return;
1751
1752         list_for_each_entry(segbuf, logs, sb_list) {
1753                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1754                                     b_assoc_buffers) {
1755                         if (bh->b_page != bd_page) {
1756                                 if (bd_page)
1757                                         end_page_writeback(bd_page);
1758                                 bd_page = bh->b_page;
1759                         }
1760                 }
1761
1762                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1763                                     b_assoc_buffers) {
1764                         clear_buffer_async_write(bh);
1765                         if (bh == segbuf->sb_super_root) {
1766                                 if (bh->b_page != bd_page) {
1767                                         end_page_writeback(bd_page);
1768                                         bd_page = bh->b_page;
1769                                 }
1770                                 break;
1771                         }
1772                         if (bh->b_page != fs_page) {
1773                                 nilfs_end_page_io(fs_page, err);
1774                                 fs_page = bh->b_page;
1775                         }
1776                 }
1777         }
1778         if (bd_page)
1779                 end_page_writeback(bd_page);
1780
1781         nilfs_end_page_io(fs_page, err);
1782 }
1783
1784 static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
1785                                              struct the_nilfs *nilfs, int err)
1786 {
1787         LIST_HEAD(logs);
1788         int ret;
1789
1790         list_splice_tail_init(&sci->sc_write_logs, &logs);
1791         ret = nilfs_wait_on_logs(&logs);
1792         nilfs_abort_logs(&logs, ret ? : err);
1793
1794         list_splice_tail_init(&sci->sc_segbufs, &logs);
1795         nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
1796         nilfs_free_incomplete_logs(&logs, nilfs);
1797
1798         if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1799                 ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1800                                                 sci->sc_freesegs,
1801                                                 sci->sc_nfreesegs,
1802                                                 NULL);
1803                 WARN_ON(ret); /* do not happen */
1804         }
1805
1806         nilfs_destroy_logs(&logs);
1807 }
1808
1809 static void nilfs_set_next_segment(struct the_nilfs *nilfs,
1810                                    struct nilfs_segment_buffer *segbuf)
1811 {
1812         nilfs->ns_segnum = segbuf->sb_segnum;
1813         nilfs->ns_nextnum = segbuf->sb_nextnum;
1814         nilfs->ns_pseg_offset = segbuf->sb_pseg_start - segbuf->sb_fseg_start
1815                 + segbuf->sb_sum.nblocks;
1816         nilfs->ns_seg_seq = segbuf->sb_sum.seg_seq;
1817         nilfs->ns_ctime = segbuf->sb_sum.ctime;
1818 }
1819
1820 static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
1821 {
1822         struct nilfs_segment_buffer *segbuf;
1823         struct page *bd_page = NULL, *fs_page = NULL;
1824         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1825         int update_sr = false;
1826
1827         list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
1828                 struct buffer_head *bh;
1829
1830                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1831                                     b_assoc_buffers) {
1832                         set_buffer_uptodate(bh);
1833                         clear_buffer_dirty(bh);
1834                         if (bh->b_page != bd_page) {
1835                                 if (bd_page)
1836                                         end_page_writeback(bd_page);
1837                                 bd_page = bh->b_page;
1838                         }
1839                 }
1840                 /*
1841                  * We assume that the buffers which belong to the same page
1842                  * continue over the buffer list.
1843                  * Under this assumption, the last BHs of pages is
1844                  * identifiable by the discontinuity of bh->b_page
1845                  * (page != fs_page).
1846                  *
1847                  * For B-tree node blocks, however, this assumption is not
1848                  * guaranteed.  The cleanup code of B-tree node pages needs
1849                  * special care.
1850                  */
1851                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1852                                     b_assoc_buffers) {
1853                         const unsigned long set_bits = BIT(BH_Uptodate);
1854                         const unsigned long clear_bits =
1855                                 (BIT(BH_Dirty) | BIT(BH_Async_Write) |
1856                                  BIT(BH_Delay) | BIT(BH_NILFS_Volatile) |
1857                                  BIT(BH_NILFS_Redirected));
1858
1859                         set_mask_bits(&bh->b_state, clear_bits, set_bits);
1860                         if (bh == segbuf->sb_super_root) {
1861                                 if (bh->b_page != bd_page) {
1862                                         end_page_writeback(bd_page);
1863                                         bd_page = bh->b_page;
1864                                 }
1865                                 update_sr = true;
1866                                 break;
1867                         }
1868                         if (bh->b_page != fs_page) {
1869                                 nilfs_end_page_io(fs_page, 0);
1870                                 fs_page = bh->b_page;
1871                         }
1872                 }
1873
1874                 if (!nilfs_segbuf_simplex(segbuf)) {
1875                         if (segbuf->sb_sum.flags & NILFS_SS_LOGBGN) {
1876                                 set_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1877                                 sci->sc_lseg_stime = jiffies;
1878                         }
1879                         if (segbuf->sb_sum.flags & NILFS_SS_LOGEND)
1880                                 clear_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1881                 }
1882         }
1883         /*
1884          * Since pages may continue over multiple segment buffers,
1885          * end of the last page must be checked outside of the loop.
1886          */
1887         if (bd_page)
1888                 end_page_writeback(bd_page);
1889
1890         nilfs_end_page_io(fs_page, 0);
1891
1892         nilfs_drop_collected_inodes(&sci->sc_dirty_files);
1893
1894         if (nilfs_doing_gc())
1895                 nilfs_drop_collected_inodes(&sci->sc_gc_inodes);
1896         else
1897                 nilfs->ns_nongc_ctime = sci->sc_seg_ctime;
1898
1899         sci->sc_nblk_inc += sci->sc_nblk_this_inc;
1900
1901         segbuf = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1902         nilfs_set_next_segment(nilfs, segbuf);
1903
1904         if (update_sr) {
1905                 nilfs->ns_flushed_device = 0;
1906                 nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
1907                                        segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
1908
1909                 clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
1910                 clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1911                 set_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1912                 nilfs_segctor_clear_metadata_dirty(sci);
1913         } else
1914                 clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1915 }
1916
1917 static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
1918 {
1919         int ret;
1920
1921         ret = nilfs_wait_on_logs(&sci->sc_write_logs);
1922         if (!ret) {
1923                 nilfs_segctor_complete_write(sci);
1924                 nilfs_destroy_logs(&sci->sc_write_logs);
1925         }
1926         return ret;
1927 }
1928
1929 static int nilfs_segctor_collect_dirty_files(struct nilfs_sc_info *sci,
1930                                              struct the_nilfs *nilfs)
1931 {
1932         struct nilfs_inode_info *ii, *n;
1933         struct inode *ifile = sci->sc_root->ifile;
1934
1935         spin_lock(&nilfs->ns_inode_lock);
1936  retry:
1937         list_for_each_entry_safe(ii, n, &nilfs->ns_dirty_files, i_dirty) {
1938                 if (!ii->i_bh) {
1939                         struct buffer_head *ibh;
1940                         int err;
1941
1942                         spin_unlock(&nilfs->ns_inode_lock);
1943                         err = nilfs_ifile_get_inode_block(
1944                                 ifile, ii->vfs_inode.i_ino, &ibh);
1945                         if (unlikely(err)) {
1946                                 nilfs_warn(sci->sc_super,
1947                                            "log writer: error %d getting inode block (ino=%lu)",
1948                                            err, ii->vfs_inode.i_ino);
1949                                 return err;
1950                         }
1951                         spin_lock(&nilfs->ns_inode_lock);
1952                         if (likely(!ii->i_bh))
1953                                 ii->i_bh = ibh;
1954                         else
1955                                 brelse(ibh);
1956                         goto retry;
1957                 }
1958
1959                 // Always redirty the buffer to avoid race condition
1960                 mark_buffer_dirty(ii->i_bh);
1961                 nilfs_mdt_mark_dirty(ifile);
1962
1963                 clear_bit(NILFS_I_QUEUED, &ii->i_state);
1964                 set_bit(NILFS_I_BUSY, &ii->i_state);
1965                 list_move_tail(&ii->i_dirty, &sci->sc_dirty_files);
1966         }
1967         spin_unlock(&nilfs->ns_inode_lock);
1968
1969         return 0;
1970 }
1971
1972 static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
1973                                              struct the_nilfs *nilfs)
1974 {
1975         struct nilfs_inode_info *ii, *n;
1976         int during_mount = !(sci->sc_super->s_flags & SB_ACTIVE);
1977         int defer_iput = false;
1978
1979         spin_lock(&nilfs->ns_inode_lock);
1980         list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
1981                 if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
1982                     test_bit(NILFS_I_DIRTY, &ii->i_state))
1983                         continue;
1984
1985                 clear_bit(NILFS_I_BUSY, &ii->i_state);
1986                 brelse(ii->i_bh);
1987                 ii->i_bh = NULL;
1988                 list_del_init(&ii->i_dirty);
1989                 if (!ii->vfs_inode.i_nlink || during_mount) {
1990                         /*
1991                          * Defer calling iput() to avoid deadlocks if
1992                          * i_nlink == 0 or mount is not yet finished.
1993                          */
1994                         list_add_tail(&ii->i_dirty, &sci->sc_iput_queue);
1995                         defer_iput = true;
1996                 } else {
1997                         spin_unlock(&nilfs->ns_inode_lock);
1998                         iput(&ii->vfs_inode);
1999                         spin_lock(&nilfs->ns_inode_lock);
2000                 }
2001         }
2002         spin_unlock(&nilfs->ns_inode_lock);
2003
2004         if (defer_iput)
2005                 schedule_work(&sci->sc_iput_work);
2006 }
2007
2008 /*
2009  * Main procedure of segment constructor
2010  */
2011 static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
2012 {
2013         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2014         int err;
2015
2016         nilfs_sc_cstage_set(sci, NILFS_ST_INIT);
2017         sci->sc_cno = nilfs->ns_cno;
2018
2019         err = nilfs_segctor_collect_dirty_files(sci, nilfs);
2020         if (unlikely(err))
2021                 goto out;
2022
2023         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
2024                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
2025
2026         if (nilfs_segctor_clean(sci))
2027                 goto out;
2028
2029         do {
2030                 sci->sc_stage.flags &= ~NILFS_CF_HISTORY_MASK;
2031
2032                 err = nilfs_segctor_begin_construction(sci, nilfs);
2033                 if (unlikely(err))
2034                         goto out;
2035
2036                 /* Update time stamp */
2037                 sci->sc_seg_ctime = ktime_get_real_seconds();
2038
2039                 err = nilfs_segctor_collect(sci, nilfs, mode);
2040                 if (unlikely(err))
2041                         goto failed;
2042
2043                 /* Avoid empty segment */
2044                 if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE &&
2045                     nilfs_segbuf_empty(sci->sc_curseg)) {
2046                         nilfs_segctor_abort_construction(sci, nilfs, 1);
2047                         goto out;
2048                 }
2049
2050                 err = nilfs_segctor_assign(sci, mode);
2051                 if (unlikely(err))
2052                         goto failed;
2053
2054                 if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2055                         nilfs_segctor_fill_in_file_bmap(sci);
2056
2057                 if (mode == SC_LSEG_SR &&
2058                     nilfs_sc_cstage_get(sci) >= NILFS_ST_CPFILE) {
2059                         err = nilfs_segctor_fill_in_checkpoint(sci);
2060                         if (unlikely(err))
2061                                 goto failed_to_write;
2062
2063                         nilfs_segctor_fill_in_super_root(sci, nilfs);
2064                 }
2065                 nilfs_segctor_update_segusage(sci, nilfs->ns_sufile);
2066
2067                 /* Write partial segments */
2068                 nilfs_segctor_prepare_write(sci);
2069
2070                 nilfs_add_checksums_on_logs(&sci->sc_segbufs,
2071                                             nilfs->ns_crc_seed);
2072
2073                 err = nilfs_segctor_write(sci, nilfs);
2074                 if (unlikely(err))
2075                         goto failed_to_write;
2076
2077                 if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE ||
2078                     nilfs->ns_blocksize_bits != PAGE_SHIFT) {
2079                         /*
2080                          * At this point, we avoid double buffering
2081                          * for blocksize < pagesize because page dirty
2082                          * flag is turned off during write and dirty
2083                          * buffers are not properly collected for
2084                          * pages crossing over segments.
2085                          */
2086                         err = nilfs_segctor_wait(sci);
2087                         if (err)
2088                                 goto failed_to_write;
2089                 }
2090         } while (nilfs_sc_cstage_get(sci) != NILFS_ST_DONE);
2091
2092  out:
2093         nilfs_segctor_drop_written_files(sci, nilfs);
2094         return err;
2095
2096  failed_to_write:
2097         if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2098                 nilfs_redirty_inodes(&sci->sc_dirty_files);
2099
2100  failed:
2101         if (nilfs_doing_gc())
2102                 nilfs_redirty_inodes(&sci->sc_gc_inodes);
2103         nilfs_segctor_abort_construction(sci, nilfs, err);
2104         goto out;
2105 }
2106
2107 /**
2108  * nilfs_segctor_start_timer - set timer of background write
2109  * @sci: nilfs_sc_info
2110  *
2111  * If the timer has already been set, it ignores the new request.
2112  * This function MUST be called within a section locking the segment
2113  * semaphore.
2114  */
2115 static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
2116 {
2117         spin_lock(&sci->sc_state_lock);
2118         if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
2119                 sci->sc_timer.expires = jiffies + sci->sc_interval;
2120                 add_timer(&sci->sc_timer);
2121                 sci->sc_state |= NILFS_SEGCTOR_COMMIT;
2122         }
2123         spin_unlock(&sci->sc_state_lock);
2124 }
2125
2126 static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
2127 {
2128         spin_lock(&sci->sc_state_lock);
2129         if (!(sci->sc_flush_request & BIT(bn))) {
2130                 unsigned long prev_req = sci->sc_flush_request;
2131
2132                 sci->sc_flush_request |= BIT(bn);
2133                 if (!prev_req)
2134                         wake_up(&sci->sc_wait_daemon);
2135         }
2136         spin_unlock(&sci->sc_state_lock);
2137 }
2138
2139 /**
2140  * nilfs_flush_segment - trigger a segment construction for resource control
2141  * @sb: super block
2142  * @ino: inode number of the file to be flushed out.
2143  */
2144 void nilfs_flush_segment(struct super_block *sb, ino_t ino)
2145 {
2146         struct the_nilfs *nilfs = sb->s_fs_info;
2147         struct nilfs_sc_info *sci = nilfs->ns_writer;
2148
2149         if (!sci || nilfs_doing_construction())
2150                 return;
2151         nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
2152                                         /* assign bit 0 to data files */
2153 }
2154
2155 struct nilfs_segctor_wait_request {
2156         wait_queue_entry_t      wq;
2157         __u32           seq;
2158         int             err;
2159         atomic_t        done;
2160 };
2161
2162 static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
2163 {
2164         struct nilfs_segctor_wait_request wait_req;
2165         int err = 0;
2166
2167         spin_lock(&sci->sc_state_lock);
2168         init_wait(&wait_req.wq);
2169         wait_req.err = 0;
2170         atomic_set(&wait_req.done, 0);
2171         wait_req.seq = ++sci->sc_seq_request;
2172         spin_unlock(&sci->sc_state_lock);
2173
2174         init_waitqueue_entry(&wait_req.wq, current);
2175         add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
2176         set_current_state(TASK_INTERRUPTIBLE);
2177         wake_up(&sci->sc_wait_daemon);
2178
2179         for (;;) {
2180                 if (atomic_read(&wait_req.done)) {
2181                         err = wait_req.err;
2182                         break;
2183                 }
2184                 if (!signal_pending(current)) {
2185                         schedule();
2186                         continue;
2187                 }
2188                 err = -ERESTARTSYS;
2189                 break;
2190         }
2191         finish_wait(&sci->sc_wait_request, &wait_req.wq);
2192         return err;
2193 }
2194
2195 static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
2196 {
2197         struct nilfs_segctor_wait_request *wrq, *n;
2198         unsigned long flags;
2199
2200         spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
2201         list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.head, wq.entry) {
2202                 if (!atomic_read(&wrq->done) &&
2203                     nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
2204                         wrq->err = err;
2205                         atomic_set(&wrq->done, 1);
2206                 }
2207                 if (atomic_read(&wrq->done)) {
2208                         wrq->wq.func(&wrq->wq,
2209                                      TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
2210                                      0, NULL);
2211                 }
2212         }
2213         spin_unlock_irqrestore(&sci->sc_wait_request.lock, flags);
2214 }
2215
2216 /**
2217  * nilfs_construct_segment - construct a logical segment
2218  * @sb: super block
2219  *
2220  * Return Value: On success, 0 is returned. On errors, one of the following
2221  * negative error code is returned.
2222  *
2223  * %-EROFS - Read only filesystem.
2224  *
2225  * %-EIO - I/O error
2226  *
2227  * %-ENOSPC - No space left on device (only in a panic state).
2228  *
2229  * %-ERESTARTSYS - Interrupted.
2230  *
2231  * %-ENOMEM - Insufficient memory available.
2232  */
2233 int nilfs_construct_segment(struct super_block *sb)
2234 {
2235         struct the_nilfs *nilfs = sb->s_fs_info;
2236         struct nilfs_sc_info *sci = nilfs->ns_writer;
2237         struct nilfs_transaction_info *ti;
2238         int err;
2239
2240         if (!sci)
2241                 return -EROFS;
2242
2243         /* A call inside transactions causes a deadlock. */
2244         BUG_ON((ti = current->journal_info) && ti->ti_magic == NILFS_TI_MAGIC);
2245
2246         err = nilfs_segctor_sync(sci);
2247         return err;
2248 }
2249
2250 /**
2251  * nilfs_construct_dsync_segment - construct a data-only logical segment
2252  * @sb: super block
2253  * @inode: inode whose data blocks should be written out
2254  * @start: start byte offset
2255  * @end: end byte offset (inclusive)
2256  *
2257  * Return Value: On success, 0 is returned. On errors, one of the following
2258  * negative error code is returned.
2259  *
2260  * %-EROFS - Read only filesystem.
2261  *
2262  * %-EIO - I/O error
2263  *
2264  * %-ENOSPC - No space left on device (only in a panic state).
2265  *
2266  * %-ERESTARTSYS - Interrupted.
2267  *
2268  * %-ENOMEM - Insufficient memory available.
2269  */
2270 int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
2271                                   loff_t start, loff_t end)
2272 {
2273         struct the_nilfs *nilfs = sb->s_fs_info;
2274         struct nilfs_sc_info *sci = nilfs->ns_writer;
2275         struct nilfs_inode_info *ii;
2276         struct nilfs_transaction_info ti;
2277         int err = 0;
2278
2279         if (!sci)
2280                 return -EROFS;
2281
2282         nilfs_transaction_lock(sb, &ti, 0);
2283
2284         ii = NILFS_I(inode);
2285         if (test_bit(NILFS_I_INODE_SYNC, &ii->i_state) ||
2286             nilfs_test_opt(nilfs, STRICT_ORDER) ||
2287             test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2288             nilfs_discontinued(nilfs)) {
2289                 nilfs_transaction_unlock(sb);
2290                 err = nilfs_segctor_sync(sci);
2291                 return err;
2292         }
2293
2294         spin_lock(&nilfs->ns_inode_lock);
2295         if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
2296             !test_bit(NILFS_I_BUSY, &ii->i_state)) {
2297                 spin_unlock(&nilfs->ns_inode_lock);
2298                 nilfs_transaction_unlock(sb);
2299                 return 0;
2300         }
2301         spin_unlock(&nilfs->ns_inode_lock);
2302         sci->sc_dsync_inode = ii;
2303         sci->sc_dsync_start = start;
2304         sci->sc_dsync_end = end;
2305
2306         err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC);
2307         if (!err)
2308                 nilfs->ns_flushed_device = 0;
2309
2310         nilfs_transaction_unlock(sb);
2311         return err;
2312 }
2313
2314 #define FLUSH_FILE_BIT  (0x1) /* data file only */
2315 #define FLUSH_DAT_BIT   BIT(NILFS_DAT_INO) /* DAT only */
2316
2317 /**
2318  * nilfs_segctor_accept - record accepted sequence count of log-write requests
2319  * @sci: segment constructor object
2320  */
2321 static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
2322 {
2323         spin_lock(&sci->sc_state_lock);
2324         sci->sc_seq_accepted = sci->sc_seq_request;
2325         spin_unlock(&sci->sc_state_lock);
2326         del_timer_sync(&sci->sc_timer);
2327 }
2328
2329 /**
2330  * nilfs_segctor_notify - notify the result of request to caller threads
2331  * @sci: segment constructor object
2332  * @mode: mode of log forming
2333  * @err: error code to be notified
2334  */
2335 static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
2336 {
2337         /* Clear requests (even when the construction failed) */
2338         spin_lock(&sci->sc_state_lock);
2339
2340         if (mode == SC_LSEG_SR) {
2341                 sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
2342                 sci->sc_seq_done = sci->sc_seq_accepted;
2343                 nilfs_segctor_wakeup(sci, err);
2344                 sci->sc_flush_request = 0;
2345         } else {
2346                 if (mode == SC_FLUSH_FILE)
2347                         sci->sc_flush_request &= ~FLUSH_FILE_BIT;
2348                 else if (mode == SC_FLUSH_DAT)
2349                         sci->sc_flush_request &= ~FLUSH_DAT_BIT;
2350
2351                 /* re-enable timer if checkpoint creation was not done */
2352                 if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2353                     time_before(jiffies, sci->sc_timer.expires))
2354                         add_timer(&sci->sc_timer);
2355         }
2356         spin_unlock(&sci->sc_state_lock);
2357 }
2358
2359 /**
2360  * nilfs_segctor_construct - form logs and write them to disk
2361  * @sci: segment constructor object
2362  * @mode: mode of log forming
2363  */
2364 static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
2365 {
2366         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2367         struct nilfs_super_block **sbp;
2368         int err = 0;
2369
2370         nilfs_segctor_accept(sci);
2371
2372         if (nilfs_discontinued(nilfs))
2373                 mode = SC_LSEG_SR;
2374         if (!nilfs_segctor_confirm(sci))
2375                 err = nilfs_segctor_do_construct(sci, mode);
2376
2377         if (likely(!err)) {
2378                 if (mode != SC_FLUSH_DAT)
2379                         atomic_set(&nilfs->ns_ndirtyblks, 0);
2380                 if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
2381                     nilfs_discontinued(nilfs)) {
2382                         down_write(&nilfs->ns_sem);
2383                         err = -EIO;
2384                         sbp = nilfs_prepare_super(sci->sc_super,
2385                                                   nilfs_sb_will_flip(nilfs));
2386                         if (likely(sbp)) {
2387                                 nilfs_set_log_cursor(sbp[0], nilfs);
2388                                 err = nilfs_commit_super(sci->sc_super,
2389                                                          NILFS_SB_COMMIT);
2390                         }
2391                         up_write(&nilfs->ns_sem);
2392                 }
2393         }
2394
2395         nilfs_segctor_notify(sci, mode, err);
2396         return err;
2397 }
2398
2399 static void nilfs_construction_timeout(struct timer_list *t)
2400 {
2401         struct nilfs_sc_info *sci = from_timer(sci, t, sc_timer);
2402
2403         wake_up_process(sci->sc_timer_task);
2404 }
2405
2406 static void
2407 nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
2408 {
2409         struct nilfs_inode_info *ii, *n;
2410
2411         list_for_each_entry_safe(ii, n, head, i_dirty) {
2412                 if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
2413                         continue;
2414                 list_del_init(&ii->i_dirty);
2415                 truncate_inode_pages(&ii->vfs_inode.i_data, 0);
2416                 nilfs_btnode_cache_clear(ii->i_assoc_inode->i_mapping);
2417                 iput(&ii->vfs_inode);
2418         }
2419 }
2420
2421 int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
2422                          void **kbufs)
2423 {
2424         struct the_nilfs *nilfs = sb->s_fs_info;
2425         struct nilfs_sc_info *sci = nilfs->ns_writer;
2426         struct nilfs_transaction_info ti;
2427         int err;
2428
2429         if (unlikely(!sci))
2430                 return -EROFS;
2431
2432         nilfs_transaction_lock(sb, &ti, 1);
2433
2434         err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
2435         if (unlikely(err))
2436                 goto out_unlock;
2437
2438         err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
2439         if (unlikely(err)) {
2440                 nilfs_mdt_restore_from_shadow_map(nilfs->ns_dat);
2441                 goto out_unlock;
2442         }
2443
2444         sci->sc_freesegs = kbufs[4];
2445         sci->sc_nfreesegs = argv[4].v_nmembs;
2446         list_splice_tail_init(&nilfs->ns_gc_inodes, &sci->sc_gc_inodes);
2447
2448         for (;;) {
2449                 err = nilfs_segctor_construct(sci, SC_LSEG_SR);
2450                 nilfs_remove_written_gcinodes(nilfs, &sci->sc_gc_inodes);
2451
2452                 if (likely(!err))
2453                         break;
2454
2455                 nilfs_warn(sb, "error %d cleaning segments", err);
2456                 set_current_state(TASK_INTERRUPTIBLE);
2457                 schedule_timeout(sci->sc_interval);
2458         }
2459         if (nilfs_test_opt(nilfs, DISCARD)) {
2460                 int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
2461                                                  sci->sc_nfreesegs);
2462                 if (ret) {
2463                         nilfs_warn(sb,
2464                                    "error %d on discard request, turning discards off for the device",
2465                                    ret);
2466                         nilfs_clear_opt(nilfs, DISCARD);
2467                 }
2468         }
2469
2470  out_unlock:
2471         sci->sc_freesegs = NULL;
2472         sci->sc_nfreesegs = 0;
2473         nilfs_mdt_clear_shadow_map(nilfs->ns_dat);
2474         nilfs_transaction_unlock(sb);
2475         return err;
2476 }
2477
2478 static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
2479 {
2480         struct nilfs_transaction_info ti;
2481
2482         nilfs_transaction_lock(sci->sc_super, &ti, 0);
2483         nilfs_segctor_construct(sci, mode);
2484
2485         /*
2486          * Unclosed segment should be retried.  We do this using sc_timer.
2487          * Timeout of sc_timer will invoke complete construction which leads
2488          * to close the current logical segment.
2489          */
2490         if (test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags))
2491                 nilfs_segctor_start_timer(sci);
2492
2493         nilfs_transaction_unlock(sci->sc_super);
2494 }
2495
2496 static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
2497 {
2498         int mode = 0;
2499
2500         spin_lock(&sci->sc_state_lock);
2501         mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
2502                 SC_FLUSH_DAT : SC_FLUSH_FILE;
2503         spin_unlock(&sci->sc_state_lock);
2504
2505         if (mode) {
2506                 nilfs_segctor_do_construct(sci, mode);
2507
2508                 spin_lock(&sci->sc_state_lock);
2509                 sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
2510                         ~FLUSH_FILE_BIT : ~FLUSH_DAT_BIT;
2511                 spin_unlock(&sci->sc_state_lock);
2512         }
2513         clear_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
2514 }
2515
2516 static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
2517 {
2518         if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2519             time_before(jiffies, sci->sc_lseg_stime + sci->sc_mjcp_freq)) {
2520                 if (!(sci->sc_flush_request & ~FLUSH_FILE_BIT))
2521                         return SC_FLUSH_FILE;
2522                 else if (!(sci->sc_flush_request & ~FLUSH_DAT_BIT))
2523                         return SC_FLUSH_DAT;
2524         }
2525         return SC_LSEG_SR;
2526 }
2527
2528 /**
2529  * nilfs_segctor_thread - main loop of the segment constructor thread.
2530  * @arg: pointer to a struct nilfs_sc_info.
2531  *
2532  * nilfs_segctor_thread() initializes a timer and serves as a daemon
2533  * to execute segment constructions.
2534  */
2535 static int nilfs_segctor_thread(void *arg)
2536 {
2537         struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
2538         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2539         int timeout = 0;
2540
2541         sci->sc_timer_task = current;
2542
2543         /* start sync. */
2544         sci->sc_task = current;
2545         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_start_thread() */
2546         nilfs_info(sci->sc_super,
2547                    "segctord starting. Construction interval = %lu seconds, CP frequency < %lu seconds",
2548                    sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
2549
2550         spin_lock(&sci->sc_state_lock);
2551  loop:
2552         for (;;) {
2553                 int mode;
2554
2555                 if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2556                         goto end_thread;
2557
2558                 if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2559                         mode = SC_LSEG_SR;
2560                 else if (sci->sc_flush_request)
2561                         mode = nilfs_segctor_flush_mode(sci);
2562                 else
2563                         break;
2564
2565                 spin_unlock(&sci->sc_state_lock);
2566                 nilfs_segctor_thread_construct(sci, mode);
2567                 spin_lock(&sci->sc_state_lock);
2568                 timeout = 0;
2569         }
2570
2571
2572         if (freezing(current)) {
2573                 spin_unlock(&sci->sc_state_lock);
2574                 try_to_freeze();
2575                 spin_lock(&sci->sc_state_lock);
2576         } else {
2577                 DEFINE_WAIT(wait);
2578                 int should_sleep = 1;
2579
2580                 prepare_to_wait(&sci->sc_wait_daemon, &wait,
2581                                 TASK_INTERRUPTIBLE);
2582
2583                 if (sci->sc_seq_request != sci->sc_seq_done)
2584                         should_sleep = 0;
2585                 else if (sci->sc_flush_request)
2586                         should_sleep = 0;
2587                 else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2588                         should_sleep = time_before(jiffies,
2589                                         sci->sc_timer.expires);
2590
2591                 if (should_sleep) {
2592                         spin_unlock(&sci->sc_state_lock);
2593                         schedule();
2594                         spin_lock(&sci->sc_state_lock);
2595                 }
2596                 finish_wait(&sci->sc_wait_daemon, &wait);
2597                 timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2598                            time_after_eq(jiffies, sci->sc_timer.expires));
2599
2600                 if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2601                         set_nilfs_discontinued(nilfs);
2602         }
2603         goto loop;
2604
2605  end_thread:
2606         spin_unlock(&sci->sc_state_lock);
2607
2608         /* end sync. */
2609         sci->sc_task = NULL;
2610         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
2611         return 0;
2612 }
2613
2614 static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2615 {
2616         struct task_struct *t;
2617
2618         t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2619         if (IS_ERR(t)) {
2620                 int err = PTR_ERR(t);
2621
2622                 nilfs_err(sci->sc_super, "error %d creating segctord thread",
2623                           err);
2624                 return err;
2625         }
2626         wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2627         return 0;
2628 }
2629
2630 static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2631         __acquires(&sci->sc_state_lock)
2632         __releases(&sci->sc_state_lock)
2633 {
2634         sci->sc_state |= NILFS_SEGCTOR_QUIT;
2635
2636         while (sci->sc_task) {
2637                 wake_up(&sci->sc_wait_daemon);
2638                 spin_unlock(&sci->sc_state_lock);
2639                 wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2640                 spin_lock(&sci->sc_state_lock);
2641         }
2642 }
2643
2644 /*
2645  * Setup & clean-up functions
2646  */
2647 static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
2648                                                struct nilfs_root *root)
2649 {
2650         struct the_nilfs *nilfs = sb->s_fs_info;
2651         struct nilfs_sc_info *sci;
2652
2653         sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2654         if (!sci)
2655                 return NULL;
2656
2657         sci->sc_super = sb;
2658
2659         nilfs_get_root(root);
2660         sci->sc_root = root;
2661
2662         init_waitqueue_head(&sci->sc_wait_request);
2663         init_waitqueue_head(&sci->sc_wait_daemon);
2664         init_waitqueue_head(&sci->sc_wait_task);
2665         spin_lock_init(&sci->sc_state_lock);
2666         INIT_LIST_HEAD(&sci->sc_dirty_files);
2667         INIT_LIST_HEAD(&sci->sc_segbufs);
2668         INIT_LIST_HEAD(&sci->sc_write_logs);
2669         INIT_LIST_HEAD(&sci->sc_gc_inodes);
2670         INIT_LIST_HEAD(&sci->sc_iput_queue);
2671         INIT_WORK(&sci->sc_iput_work, nilfs_iput_work_func);
2672         timer_setup(&sci->sc_timer, nilfs_construction_timeout, 0);
2673
2674         sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2675         sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2676         sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2677
2678         if (nilfs->ns_interval)
2679                 sci->sc_interval = HZ * nilfs->ns_interval;
2680         if (nilfs->ns_watermark)
2681                 sci->sc_watermark = nilfs->ns_watermark;
2682         return sci;
2683 }
2684
2685 static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2686 {
2687         int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2688
2689         /*
2690          * The segctord thread was stopped and its timer was removed.
2691          * But some tasks remain.
2692          */
2693         do {
2694                 struct nilfs_transaction_info ti;
2695
2696                 nilfs_transaction_lock(sci->sc_super, &ti, 0);
2697                 ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2698                 nilfs_transaction_unlock(sci->sc_super);
2699
2700                 flush_work(&sci->sc_iput_work);
2701
2702         } while (ret && retrycount-- > 0);
2703 }
2704
2705 /**
2706  * nilfs_segctor_destroy - destroy the segment constructor.
2707  * @sci: nilfs_sc_info
2708  *
2709  * nilfs_segctor_destroy() kills the segctord thread and frees
2710  * the nilfs_sc_info struct.
2711  * Caller must hold the segment semaphore.
2712  */
2713 static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2714 {
2715         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2716         int flag;
2717
2718         up_write(&nilfs->ns_segctor_sem);
2719
2720         spin_lock(&sci->sc_state_lock);
2721         nilfs_segctor_kill_thread(sci);
2722         flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2723                 || sci->sc_seq_request != sci->sc_seq_done);
2724         spin_unlock(&sci->sc_state_lock);
2725
2726         if (flush_work(&sci->sc_iput_work))
2727                 flag = true;
2728
2729         if (flag || !nilfs_segctor_confirm(sci))
2730                 nilfs_segctor_write_out(sci);
2731
2732         if (!list_empty(&sci->sc_dirty_files)) {
2733                 nilfs_warn(sci->sc_super,
2734                            "disposed unprocessed dirty file(s) when stopping log writer");
2735                 nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2736         }
2737
2738         if (!list_empty(&sci->sc_iput_queue)) {
2739                 nilfs_warn(sci->sc_super,
2740                            "disposed unprocessed inode(s) in iput queue when stopping log writer");
2741                 nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 1);
2742         }
2743
2744         WARN_ON(!list_empty(&sci->sc_segbufs));
2745         WARN_ON(!list_empty(&sci->sc_write_logs));
2746
2747         nilfs_put_root(sci->sc_root);
2748
2749         down_write(&nilfs->ns_segctor_sem);
2750
2751         del_timer_sync(&sci->sc_timer);
2752         kfree(sci);
2753 }
2754
2755 /**
2756  * nilfs_attach_log_writer - attach log writer
2757  * @sb: super block instance
2758  * @root: root object of the current filesystem tree
2759  *
2760  * This allocates a log writer object, initializes it, and starts the
2761  * log writer.
2762  *
2763  * Return Value: On success, 0 is returned. On error, one of the following
2764  * negative error code is returned.
2765  *
2766  * %-ENOMEM - Insufficient memory available.
2767  */
2768 int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
2769 {
2770         struct the_nilfs *nilfs = sb->s_fs_info;
2771         int err;
2772
2773         if (nilfs->ns_writer) {
2774                 /*
2775                  * This happens if the filesystem was remounted
2776                  * read/write after nilfs_error degenerated it into a
2777                  * read-only mount.
2778                  */
2779                 nilfs_detach_log_writer(sb);
2780         }
2781
2782         nilfs->ns_writer = nilfs_segctor_new(sb, root);
2783         if (!nilfs->ns_writer)
2784                 return -ENOMEM;
2785
2786         inode_attach_wb(nilfs->ns_bdev->bd_inode, NULL);
2787
2788         err = nilfs_segctor_start_thread(nilfs->ns_writer);
2789         if (err) {
2790                 kfree(nilfs->ns_writer);
2791                 nilfs->ns_writer = NULL;
2792         }
2793         return err;
2794 }
2795
2796 /**
2797  * nilfs_detach_log_writer - destroy log writer
2798  * @sb: super block instance
2799  *
2800  * This kills log writer daemon, frees the log writer object, and
2801  * destroys list of dirty files.
2802  */
2803 void nilfs_detach_log_writer(struct super_block *sb)
2804 {
2805         struct the_nilfs *nilfs = sb->s_fs_info;
2806         LIST_HEAD(garbage_list);
2807
2808         down_write(&nilfs->ns_segctor_sem);
2809         if (nilfs->ns_writer) {
2810                 nilfs_segctor_destroy(nilfs->ns_writer);
2811                 nilfs->ns_writer = NULL;
2812         }
2813
2814         /* Force to free the list of dirty files */
2815         spin_lock(&nilfs->ns_inode_lock);
2816         if (!list_empty(&nilfs->ns_dirty_files)) {
2817                 list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2818                 nilfs_warn(sb,
2819                            "disposed unprocessed dirty file(s) when detaching log writer");
2820         }
2821         spin_unlock(&nilfs->ns_inode_lock);
2822         up_write(&nilfs->ns_segctor_sem);
2823
2824         nilfs_dispose_list(nilfs, &garbage_list, 1);
2825 }