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 (sb_rdonly(sb) || unlikely(!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 /**
 434  * nilfs_segctor_zeropad_segsum - zero pad the rest of the segment summary area
 435  * @sci: segment constructor object
 436  *
 437  * nilfs_segctor_zeropad_segsum() zero-fills unallocated space at the end of
 438  * the current segment summary block.
 439  */
 440 static void nilfs_segctor_zeropad_segsum(struct nilfs_sc_info *sci)
 441 {
 442         struct nilfs_segsum_pointer *ssp;
 443
 444         ssp = sci->sc_blk_cnt > 0 ? &sci->sc_binfo_ptr : &sci->sc_finfo_ptr;
 445         if (ssp->offset < ssp->bh->b_size)
 446                 memset(ssp->bh->b_data + ssp->offset, 0,
 447                        ssp->bh->b_size - ssp->offset);
 448 }
 449
 450 static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
 451 {
 452         sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
 453         if (NILFS_SEGBUF_IS_LAST(sci->sc_curseg, &sci->sc_segbufs))
 454                 return -E2BIG; /*
 455                                 * The current segment is filled up
 456                                 * (internal code)
 457                                 */
 458         nilfs_segctor_zeropad_segsum(sci);
 459         sci->sc_curseg = NILFS_NEXT_SEGBUF(sci->sc_curseg);
 460         return nilfs_segctor_reset_segment_buffer(sci);
 461 }
 462
 463 static int nilfs_segctor_add_super_root(struct nilfs_sc_info *sci)
 464 {
 465         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 466         int err;
 467
 468         if (segbuf->sb_sum.nblocks >= segbuf->sb_rest_blocks) {
 469                 err = nilfs_segctor_feed_segment(sci);
 470                 if (err)
 471                         return err;
 472                 segbuf = sci->sc_curseg;
 473         }
 474         err = nilfs_segbuf_extend_payload(segbuf, &segbuf->sb_super_root);
 475         if (likely(!err))
 476                 segbuf->sb_sum.flags |= NILFS_SS_SR;
 477         return err;
 478 }
 479
 480 /*
 481  * Functions for making segment summary and payloads
 482  */
 483 static int nilfs_segctor_segsum_block_required(
 484         struct nilfs_sc_info *sci, const struct nilfs_segsum_pointer *ssp,
 485         unsigned int binfo_size)
 486 {
 487         unsigned int blocksize = sci->sc_super->s_blocksize;
 488         /* Size of finfo and binfo is enough small against blocksize */
 489
 490         return ssp->offset + binfo_size +
 491                 (!sci->sc_blk_cnt ? sizeof(struct nilfs_finfo) : 0) >
 492                 blocksize;
 493 }
 494
 495 static void nilfs_segctor_begin_finfo(struct nilfs_sc_info *sci,
 496                                       struct inode *inode)
 497 {
 498         sci->sc_curseg->sb_sum.nfinfo++;
 499         sci->sc_binfo_ptr = sci->sc_finfo_ptr;
 500         nilfs_segctor_map_segsum_entry(
 501                 sci, &sci->sc_binfo_ptr, sizeof(struct nilfs_finfo));
 502
 503         if (NILFS_I(inode)->i_root &&
 504             !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 505                 set_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
 506         /* skip finfo */
 507 }
 508
 509 static void nilfs_segctor_end_finfo(struct nilfs_sc_info *sci,
 510                                     struct inode *inode)
 511 {
 512         struct nilfs_finfo *finfo;
 513         struct nilfs_inode_info *ii;
 514         struct nilfs_segment_buffer *segbuf;
 515         __u64 cno;
 516
 517         if (sci->sc_blk_cnt == 0)
 518                 return;
 519
 520         ii = NILFS_I(inode);
 521
 522         if (test_bit(NILFS_I_GCINODE, &ii->i_state))
 523                 cno = ii->i_cno;
 524         else if (NILFS_ROOT_METADATA_FILE(inode->i_ino))
 525                 cno = 0;
 526         else
 527                 cno = sci->sc_cno;
 528
 529         finfo = nilfs_segctor_map_segsum_entry(sci, &sci->sc_finfo_ptr,
 530                                                  sizeof(*finfo));
 531         finfo->fi_ino = cpu_to_le64(inode->i_ino);
 532         finfo->fi_nblocks = cpu_to_le32(sci->sc_blk_cnt);
 533         finfo->fi_ndatablk = cpu_to_le32(sci->sc_datablk_cnt);
 534         finfo->fi_cno = cpu_to_le64(cno);
 535
 536         segbuf = sci->sc_curseg;
 537         segbuf->sb_sum.sumbytes = sci->sc_binfo_ptr.offset +
 538                 sci->sc_super->s_blocksize * (segbuf->sb_sum.nsumblk - 1);
 539         sci->sc_finfo_ptr = sci->sc_binfo_ptr;
 540         sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 541 }
 542
 543 static int nilfs_segctor_add_file_block(struct nilfs_sc_info *sci,
 544                                         struct buffer_head *bh,
 545                                         struct inode *inode,
 546                                         unsigned int binfo_size)
 547 {
 548         struct nilfs_segment_buffer *segbuf;
 549         int required, err = 0;
 550
 551  retry:
 552         segbuf = sci->sc_curseg;
 553         required = nilfs_segctor_segsum_block_required(
 554                 sci, &sci->sc_binfo_ptr, binfo_size);
 555         if (segbuf->sb_sum.nblocks + required + 1 > segbuf->sb_rest_blocks) {
 556                 nilfs_segctor_end_finfo(sci, inode);
 557                 err = nilfs_segctor_feed_segment(sci);
 558                 if (err)
 559                         return err;
 560                 goto retry;
 561         }
 562         if (unlikely(required)) {
 563                 nilfs_segctor_zeropad_segsum(sci);
 564                 err = nilfs_segbuf_extend_segsum(segbuf);
 565                 if (unlikely(err))
 566                         goto failed;
 567         }
 568         if (sci->sc_blk_cnt == 0)
 569                 nilfs_segctor_begin_finfo(sci, inode);
 570
 571         nilfs_segctor_map_segsum_entry(sci, &sci->sc_binfo_ptr, binfo_size);
 572         /* Substitution to vblocknr is delayed until update_blocknr() */
 573         nilfs_segbuf_add_file_buffer(segbuf, bh);
 574         sci->sc_blk_cnt++;
 575  failed:
 576         return err;
 577 }
 578
 579 /*
 580  * Callback functions that enumerate, mark, and collect dirty blocks
 581  */
 582 static int nilfs_collect_file_data(struct nilfs_sc_info *sci,
 583                                    struct buffer_head *bh, struct inode *inode)
 584 {
 585         int err;
 586
 587         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 588         if (err < 0)
 589                 return err;
 590
 591         err = nilfs_segctor_add_file_block(sci, bh, inode,
 592                                            sizeof(struct nilfs_binfo_v));
 593         if (!err)
 594                 sci->sc_datablk_cnt++;
 595         return err;
 596 }
 597
 598 static int nilfs_collect_file_node(struct nilfs_sc_info *sci,
 599                                    struct buffer_head *bh,
 600                                    struct inode *inode)
 601 {
 602         return nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 603 }
 604
 605 static int nilfs_collect_file_bmap(struct nilfs_sc_info *sci,
 606                                    struct buffer_head *bh,
 607                                    struct inode *inode)
 608 {
 609         WARN_ON(!buffer_dirty(bh));
 610         return nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 611 }
 612
 613 static void nilfs_write_file_data_binfo(struct nilfs_sc_info *sci,
 614                                         struct nilfs_segsum_pointer *ssp,
 615                                         union nilfs_binfo *binfo)
 616 {
 617         struct nilfs_binfo_v *binfo_v = nilfs_segctor_map_segsum_entry(
 618                 sci, ssp, sizeof(*binfo_v));
 619         *binfo_v = binfo->bi_v;
 620 }
 621
 622 static void nilfs_write_file_node_binfo(struct nilfs_sc_info *sci,
 623                                         struct nilfs_segsum_pointer *ssp,
 624                                         union nilfs_binfo *binfo)
 625 {
 626         __le64 *vblocknr = nilfs_segctor_map_segsum_entry(
 627                 sci, ssp, sizeof(*vblocknr));
 628         *vblocknr = binfo->bi_v.bi_vblocknr;
 629 }
 630
 631 static const struct nilfs_sc_operations nilfs_sc_file_ops = {
 632         .collect_data = nilfs_collect_file_data,
 633         .collect_node = nilfs_collect_file_node,
 634         .collect_bmap = nilfs_collect_file_bmap,
 635         .write_data_binfo = nilfs_write_file_data_binfo,
 636         .write_node_binfo = nilfs_write_file_node_binfo,
 637 };
 638
 639 static int nilfs_collect_dat_data(struct nilfs_sc_info *sci,
 640                                   struct buffer_head *bh, struct inode *inode)
 641 {
 642         int err;
 643
 644         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 645         if (err < 0)
 646                 return err;
 647
 648         err = nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 649         if (!err)
 650                 sci->sc_datablk_cnt++;
 651         return err;
 652 }
 653
 654 static int nilfs_collect_dat_bmap(struct nilfs_sc_info *sci,
 655                                   struct buffer_head *bh, struct inode *inode)
 656 {
 657         WARN_ON(!buffer_dirty(bh));
 658         return nilfs_segctor_add_file_block(sci, bh, inode,
 659                                             sizeof(struct nilfs_binfo_dat));
 660 }
 661
 662 static void nilfs_write_dat_data_binfo(struct nilfs_sc_info *sci,
 663                                        struct nilfs_segsum_pointer *ssp,
 664                                        union nilfs_binfo *binfo)
 665 {
 666         __le64 *blkoff = nilfs_segctor_map_segsum_entry(sci, ssp,
 667                                                           sizeof(*blkoff));
 668         *blkoff = binfo->bi_dat.bi_blkoff;
 669 }
 670
 671 static void nilfs_write_dat_node_binfo(struct nilfs_sc_info *sci,
 672                                        struct nilfs_segsum_pointer *ssp,
 673                                        union nilfs_binfo *binfo)
 674 {
 675         struct nilfs_binfo_dat *binfo_dat =
 676                 nilfs_segctor_map_segsum_entry(sci, ssp, sizeof(*binfo_dat));
 677         *binfo_dat = binfo->bi_dat;
 678 }
 679
 680 static const struct nilfs_sc_operations nilfs_sc_dat_ops = {
 681         .collect_data = nilfs_collect_dat_data,
 682         .collect_node = nilfs_collect_file_node,
 683         .collect_bmap = nilfs_collect_dat_bmap,
 684         .write_data_binfo = nilfs_write_dat_data_binfo,
 685         .write_node_binfo = nilfs_write_dat_node_binfo,
 686 };
 687
 688 static const struct nilfs_sc_operations nilfs_sc_dsync_ops = {
 689         .collect_data = nilfs_collect_file_data,
 690         .collect_node = NULL,
 691         .collect_bmap = NULL,
 692         .write_data_binfo = nilfs_write_file_data_binfo,
 693         .write_node_binfo = NULL,
 694 };
 695
 696 static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode,
 697                                               struct list_head *listp,
 698                                               size_t nlimit,
 699                                               loff_t start, loff_t end)
 700 {
 701         struct address_space *mapping = inode->i_mapping;
 702         struct folio_batch fbatch;
 703         pgoff_t index = 0, last = ULONG_MAX;
 704         size_t ndirties = 0;
 705         int i;
 706
 707         if (unlikely(start != 0 || end != LLONG_MAX)) {
 708                 /*
 709                  * A valid range is given for sync-ing data pages. The
 710                  * range is rounded to per-page; extra dirty buffers
 711                  * may be included if blocksize < pagesize.
 712                  */
 713                 index = start >> PAGE_SHIFT;
 714                 last = end >> PAGE_SHIFT;
 715         }
 716         folio_batch_init(&fbatch);
 717  repeat:
 718         if (unlikely(index > last) ||
 719               !filemap_get_folios_tag(mapping, &index, last,
 720                       PAGECACHE_TAG_DIRTY, &fbatch))
 721                 return ndirties;
 722
 723         for (i = 0; i < folio_batch_count(&fbatch); i++) {
 724                 struct buffer_head *bh, *head;
 725                 struct folio *folio = fbatch.folios[i];
 726
 727                 folio_lock(folio);
 728                 if (unlikely(folio->mapping != mapping)) {
 729                         /* Exclude folios removed from the address space */
 730                         folio_unlock(folio);
 731                         continue;
 732                 }
 733                 head = folio_buffers(folio);
 734                 if (!head) {
 735                         create_empty_buffers(&folio->page, i_blocksize(inode), 0);
 736                         head = folio_buffers(folio);
 737                 }
 738                 folio_unlock(folio);
 739
 740                 bh = head;
 741                 do {
 742                         if (!buffer_dirty(bh) || buffer_async_write(bh))
 743                                 continue;
 744                         get_bh(bh);
 745                         list_add_tail(&bh->b_assoc_buffers, listp);
 746                         ndirties++;
 747                         if (unlikely(ndirties >= nlimit)) {
 748                                 folio_batch_release(&fbatch);
 749                                 cond_resched();
 750                                 return ndirties;
 751                         }
 752                 } while (bh = bh->b_this_page, bh != head);
 753         }
 754         folio_batch_release(&fbatch);
 755         cond_resched();
 756         goto repeat;
 757 }
 758
 759 static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
 760                                             struct list_head *listp)
 761 {
 762         struct nilfs_inode_info *ii = NILFS_I(inode);
 763         struct inode *btnc_inode = ii->i_assoc_inode;
 764         struct folio_batch fbatch;
 765         struct buffer_head *bh, *head;
 766         unsigned int i;
 767         pgoff_t index = 0;
 768
 769         if (!btnc_inode)
 770                 return;
 771         folio_batch_init(&fbatch);
 772
 773         while (filemap_get_folios_tag(btnc_inode->i_mapping, &index,
 774                                 (pgoff_t)-1, PAGECACHE_TAG_DIRTY, &fbatch)) {
 775                 for (i = 0; i < folio_batch_count(&fbatch); i++) {
 776                         bh = head = folio_buffers(fbatch.folios[i]);
 777                         do {
 778                                 if (buffer_dirty(bh) &&
 779                                                 !buffer_async_write(bh)) {
 780                                         get_bh(bh);
 781                                         list_add_tail(&bh->b_assoc_buffers,
 782                                                       listp);
 783                                 }
 784                                 bh = bh->b_this_page;
 785                         } while (bh != head);
 786                 }
 787                 folio_batch_release(&fbatch);
 788                 cond_resched();
 789         }
 790 }
 791
 792 static void nilfs_dispose_list(struct the_nilfs *nilfs,
 793                                struct list_head *head, int force)
 794 {
 795         struct nilfs_inode_info *ii, *n;
 796         struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
 797         unsigned int nv = 0;
 798
 799         while (!list_empty(head)) {
 800                 spin_lock(&nilfs->ns_inode_lock);
 801                 list_for_each_entry_safe(ii, n, head, i_dirty) {
 802                         list_del_init(&ii->i_dirty);
 803                         if (force) {
 804                                 if (unlikely(ii->i_bh)) {
 805                                         brelse(ii->i_bh);
 806                                         ii->i_bh = NULL;
 807                                 }
 808                         } else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
 809                                 set_bit(NILFS_I_QUEUED, &ii->i_state);
 810                                 list_add_tail(&ii->i_dirty,
 811                                               &nilfs->ns_dirty_files);
 812                                 continue;
 813                         }
 814                         ivec[nv++] = ii;
 815                         if (nv == SC_N_INODEVEC)
 816                                 break;
 817                 }
 818                 spin_unlock(&nilfs->ns_inode_lock);
 819
 820                 for (pii = ivec; nv > 0; pii++, nv--)
 821                         iput(&(*pii)->vfs_inode);
 822         }
 823 }
 824
 825 static void nilfs_iput_work_func(struct work_struct *work)
 826 {
 827         struct nilfs_sc_info *sci = container_of(work, struct nilfs_sc_info,
 828                                                  sc_iput_work);
 829         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 830
 831         nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 0);
 832 }
 833
 834 static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
 835                                      struct nilfs_root *root)
 836 {
 837         int ret = 0;
 838
 839         if (nilfs_mdt_fetch_dirty(root->ifile))
 840                 ret++;
 841         if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
 842                 ret++;
 843         if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
 844                 ret++;
 845         if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
 846                 ret++;
 847         return ret;
 848 }
 849
 850 static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 851 {
 852         return list_empty(&sci->sc_dirty_files) &&
 853                 !test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
 854                 sci->sc_nfreesegs == 0 &&
 855                 (!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
 856 }
 857
 858 static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 859 {
 860         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 861         int ret = 0;
 862
 863         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
 864                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
 865
 866         spin_lock(&nilfs->ns_inode_lock);
 867         if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
 868                 ret++;
 869
 870         spin_unlock(&nilfs->ns_inode_lock);
 871         return ret;
 872 }
 873
 874 static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 875 {
 876         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 877
 878         nilfs_mdt_clear_dirty(sci->sc_root->ifile);
 879         nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
 880         nilfs_mdt_clear_dirty(nilfs->ns_sufile);
 881         nilfs_mdt_clear_dirty(nilfs->ns_dat);
 882 }
 883
 884 static int nilfs_segctor_create_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         /* XXX: this interface will be changed */
 892         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 1,
 893                                           &raw_cp, &bh_cp);
 894         if (likely(!err)) {
 895                 /*
 896                  * The following code is duplicated with cpfile.  But, it is
 897                  * needed to collect the checkpoint even if it was not newly
 898                  * created.
 899                  */
 900                 mark_buffer_dirty(bh_cp);
 901                 nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
 902                 nilfs_cpfile_put_checkpoint(
 903                         nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 904         } else if (err == -EINVAL || err == -ENOENT) {
 905                 nilfs_error(sci->sc_super,
 906                             "checkpoint creation failed due to metadata corruption.");
 907                 err = -EIO;
 908         }
 909         return err;
 910 }
 911
 912 static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
 913 {
 914         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 915         struct buffer_head *bh_cp;
 916         struct nilfs_checkpoint *raw_cp;
 917         int err;
 918
 919         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
 920                                           &raw_cp, &bh_cp);
 921         if (unlikely(err)) {
 922                 if (err == -EINVAL || err == -ENOENT) {
 923                         nilfs_error(sci->sc_super,
 924                                     "checkpoint finalization failed due to metadata corruption.");
 925                         err = -EIO;
 926                 }
 927                 goto failed_ibh;
 928         }
 929         raw_cp->cp_snapshot_list.ssl_next = 0;
 930         raw_cp->cp_snapshot_list.ssl_prev = 0;
 931         raw_cp->cp_inodes_count =
 932                 cpu_to_le64(atomic64_read(&sci->sc_root->inodes_count));
 933         raw_cp->cp_blocks_count =
 934                 cpu_to_le64(atomic64_read(&sci->sc_root->blocks_count));
 935         raw_cp->cp_nblk_inc =
 936                 cpu_to_le64(sci->sc_nblk_inc + sci->sc_nblk_this_inc);
 937         raw_cp->cp_create = cpu_to_le64(sci->sc_seg_ctime);
 938         raw_cp->cp_cno = cpu_to_le64(nilfs->ns_cno);
 939
 940         if (test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 941                 nilfs_checkpoint_clear_minor(raw_cp);
 942         else
 943                 nilfs_checkpoint_set_minor(raw_cp);
 944
 945         nilfs_write_inode_common(sci->sc_root->ifile,
 946                                  &raw_cp->cp_ifile_inode, 1);
 947         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 948         return 0;
 949
 950  failed_ibh:
 951         return err;
 952 }
 953
 954 static void nilfs_fill_in_file_bmap(struct inode *ifile,
 955                                     struct nilfs_inode_info *ii)
 956
 957 {
 958         struct buffer_head *ibh;
 959         struct nilfs_inode *raw_inode;
 960
 961         if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
 962                 ibh = ii->i_bh;
 963                 BUG_ON(!ibh);
 964                 raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
 965                                                   ibh);
 966                 nilfs_bmap_write(ii->i_bmap, raw_inode);
 967                 nilfs_ifile_unmap_inode(ifile, ii->vfs_inode.i_ino, ibh);
 968         }
 969 }
 970
 971 static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
 972 {
 973         struct nilfs_inode_info *ii;
 974
 975         list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
 976                 nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
 977                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
 978         }
 979 }
 980
 981 static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 982                                              struct the_nilfs *nilfs)
 983 {
 984         struct buffer_head *bh_sr;
 985         struct nilfs_super_root *raw_sr;
 986         unsigned int isz, srsz;
 987
 988         bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
 989
 990         lock_buffer(bh_sr);
 991         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 992         isz = nilfs->ns_inode_size;
 993         srsz = NILFS_SR_BYTES(isz);
 994
 995         raw_sr->sr_sum = 0;  /* Ensure initialization within this update */
 996         raw_sr->sr_bytes = cpu_to_le16(srsz);
 997         raw_sr->sr_nongc_ctime
 998                 = cpu_to_le64(nilfs_doing_gc() ?
 999                               nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
1000         raw_sr->sr_flags = 0;
1001
1002         nilfs_write_inode_common(nilfs->ns_dat, (void *)raw_sr +
1003                                  NILFS_SR_DAT_OFFSET(isz), 1);
1004         nilfs_write_inode_common(nilfs->ns_cpfile, (void *)raw_sr +
1005                                  NILFS_SR_CPFILE_OFFSET(isz), 1);
1006         nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
1007                                  NILFS_SR_SUFILE_OFFSET(isz), 1);
1008         memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
1009         set_buffer_uptodate(bh_sr);
1010         unlock_buffer(bh_sr);
1011 }
1012
1013 static void nilfs_redirty_inodes(struct list_head *head)
1014 {
1015         struct nilfs_inode_info *ii;
1016
1017         list_for_each_entry(ii, head, i_dirty) {
1018                 if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
1019                         clear_bit(NILFS_I_COLLECTED, &ii->i_state);
1020         }
1021 }
1022
1023 static void nilfs_drop_collected_inodes(struct list_head *head)
1024 {
1025         struct nilfs_inode_info *ii;
1026
1027         list_for_each_entry(ii, head, i_dirty) {
1028                 if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
1029                         continue;
1030
1031                 clear_bit(NILFS_I_INODE_SYNC, &ii->i_state);
1032                 set_bit(NILFS_I_UPDATED, &ii->i_state);
1033         }
1034 }
1035
1036 static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
1037                                        struct inode *inode,
1038                                        struct list_head *listp,
1039                                        int (*collect)(struct nilfs_sc_info *,
1040                                                       struct buffer_head *,
1041                                                       struct inode *))
1042 {
1043         struct buffer_head *bh, *n;
1044         int err = 0;
1045
1046         if (collect) {
1047                 list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
1048                         list_del_init(&bh->b_assoc_buffers);
1049                         err = collect(sci, bh, inode);
1050                         brelse(bh);
1051                         if (unlikely(err))
1052                                 goto dispose_buffers;
1053                 }
1054                 return 0;
1055         }
1056
1057  dispose_buffers:
1058         while (!list_empty(listp)) {
1059                 bh = list_first_entry(listp, struct buffer_head,
1060                                       b_assoc_buffers);
1061                 list_del_init(&bh->b_assoc_buffers);
1062                 brelse(bh);
1063         }
1064         return err;
1065 }
1066
1067 static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
1068 {
1069         /* Remaining number of blocks within segment buffer */
1070         return sci->sc_segbuf_nblocks -
1071                 (sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
1072 }
1073
1074 static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
1075                                    struct inode *inode,
1076                                    const struct nilfs_sc_operations *sc_ops)
1077 {
1078         LIST_HEAD(data_buffers);
1079         LIST_HEAD(node_buffers);
1080         int err;
1081
1082         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1083                 size_t n, rest = nilfs_segctor_buffer_rest(sci);
1084
1085                 n = nilfs_lookup_dirty_data_buffers(
1086                         inode, &data_buffers, rest + 1, 0, LLONG_MAX);
1087                 if (n > rest) {
1088                         err = nilfs_segctor_apply_buffers(
1089                                 sci, inode, &data_buffers,
1090                                 sc_ops->collect_data);
1091                         BUG_ON(!err); /* always receive -E2BIG or true error */
1092                         goto break_or_fail;
1093                 }
1094         }
1095         nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
1096
1097         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1098                 err = nilfs_segctor_apply_buffers(
1099                         sci, inode, &data_buffers, sc_ops->collect_data);
1100                 if (unlikely(err)) {
1101                         /* dispose node list */
1102                         nilfs_segctor_apply_buffers(
1103                                 sci, inode, &node_buffers, NULL);
1104                         goto break_or_fail;
1105                 }
1106                 sci->sc_stage.flags |= NILFS_CF_NODE;
1107         }
1108         /* Collect node */
1109         err = nilfs_segctor_apply_buffers(
1110                 sci, inode, &node_buffers, sc_ops->collect_node);
1111         if (unlikely(err))
1112                 goto break_or_fail;
1113
1114         nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1115         err = nilfs_segctor_apply_buffers(
1116                 sci, inode, &node_buffers, sc_ops->collect_bmap);
1117         if (unlikely(err))
1118                 goto break_or_fail;
1119
1120         nilfs_segctor_end_finfo(sci, inode);
1121         sci->sc_stage.flags &= ~NILFS_CF_NODE;
1122
1123  break_or_fail:
1124         return err;
1125 }
1126
1127 static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1128                                          struct inode *inode)
1129 {
1130         LIST_HEAD(data_buffers);
1131         size_t n, rest = nilfs_segctor_buffer_rest(sci);
1132         int err;
1133
1134         n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1135                                             sci->sc_dsync_start,
1136                                             sci->sc_dsync_end);
1137
1138         err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1139                                           nilfs_collect_file_data);
1140         if (!err) {
1141                 nilfs_segctor_end_finfo(sci, inode);
1142                 BUG_ON(n > rest);
1143                 /* always receive -E2BIG or true error if n > rest */
1144         }
1145         return err;
1146 }
1147
1148 static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1149 {
1150         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1151         struct list_head *head;
1152         struct nilfs_inode_info *ii;
1153         size_t ndone;
1154         int err = 0;
1155
1156         switch (nilfs_sc_cstage_get(sci)) {
1157         case NILFS_ST_INIT:
1158                 /* Pre-processes */
1159                 sci->sc_stage.flags = 0;
1160
1161                 if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1162                         sci->sc_nblk_inc = 0;
1163                         sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1164                         if (mode == SC_LSEG_DSYNC) {
1165                                 nilfs_sc_cstage_set(sci, NILFS_ST_DSYNC);
1166                                 goto dsync_mode;
1167                         }
1168                 }
1169
1170                 sci->sc_stage.dirty_file_ptr = NULL;
1171                 sci->sc_stage.gc_inode_ptr = NULL;
1172                 if (mode == SC_FLUSH_DAT) {
1173                         nilfs_sc_cstage_set(sci, NILFS_ST_DAT);
1174                         goto dat_stage;
1175                 }
1176                 nilfs_sc_cstage_inc(sci);
1177                 fallthrough;
1178         case NILFS_ST_GC:
1179                 if (nilfs_doing_gc()) {
1180                         head = &sci->sc_gc_inodes;
1181                         ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1182                                                 head, i_dirty);
1183                         list_for_each_entry_continue(ii, head, i_dirty) {
1184                                 err = nilfs_segctor_scan_file(
1185                                         sci, &ii->vfs_inode,
1186                                         &nilfs_sc_file_ops);
1187                                 if (unlikely(err)) {
1188                                         sci->sc_stage.gc_inode_ptr = list_entry(
1189                                                 ii->i_dirty.prev,
1190                                                 struct nilfs_inode_info,
1191                                                 i_dirty);
1192                                         goto break_or_fail;
1193                                 }
1194                                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
1195                         }
1196                         sci->sc_stage.gc_inode_ptr = NULL;
1197                 }
1198                 nilfs_sc_cstage_inc(sci);
1199                 fallthrough;
1200         case NILFS_ST_FILE:
1201                 head = &sci->sc_dirty_files;
1202                 ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1203                                         i_dirty);
1204                 list_for_each_entry_continue(ii, head, i_dirty) {
1205                         clear_bit(NILFS_I_DIRTY, &ii->i_state);
1206
1207                         err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1208                                                       &nilfs_sc_file_ops);
1209                         if (unlikely(err)) {
1210                                 sci->sc_stage.dirty_file_ptr =
1211                                         list_entry(ii->i_dirty.prev,
1212                                                    struct nilfs_inode_info,
1213                                                    i_dirty);
1214                                 goto break_or_fail;
1215                         }
1216                         /* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1217                         /* XXX: required ? */
1218                 }
1219                 sci->sc_stage.dirty_file_ptr = NULL;
1220                 if (mode == SC_FLUSH_FILE) {
1221                         nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1222                         return 0;
1223                 }
1224                 nilfs_sc_cstage_inc(sci);
1225                 sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1226                 fallthrough;
1227         case NILFS_ST_IFILE:
1228                 err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1229                                               &nilfs_sc_file_ops);
1230                 if (unlikely(err))
1231                         break;
1232                 nilfs_sc_cstage_inc(sci);
1233                 /* Creating a checkpoint */
1234                 err = nilfs_segctor_create_checkpoint(sci);
1235                 if (unlikely(err))
1236                         break;
1237                 fallthrough;
1238         case NILFS_ST_CPFILE:
1239                 err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1240                                               &nilfs_sc_file_ops);
1241                 if (unlikely(err))
1242                         break;
1243                 nilfs_sc_cstage_inc(sci);
1244                 fallthrough;
1245         case NILFS_ST_SUFILE:
1246                 err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1247                                          sci->sc_nfreesegs, &ndone);
1248                 if (unlikely(err)) {
1249                         nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1250                                                   sci->sc_freesegs, ndone,
1251                                                   NULL);
1252                         break;
1253                 }
1254                 sci->sc_stage.flags |= NILFS_CF_SUFREED;
1255
1256                 err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1257                                               &nilfs_sc_file_ops);
1258                 if (unlikely(err))
1259                         break;
1260                 nilfs_sc_cstage_inc(sci);
1261                 fallthrough;
1262         case NILFS_ST_DAT:
1263  dat_stage:
1264                 err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1265                                               &nilfs_sc_dat_ops);
1266                 if (unlikely(err))
1267                         break;
1268                 if (mode == SC_FLUSH_DAT) {
1269                         nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1270                         return 0;
1271                 }
1272                 nilfs_sc_cstage_inc(sci);
1273                 fallthrough;
1274         case NILFS_ST_SR:
1275                 if (mode == SC_LSEG_SR) {
1276                         /* Appending a super root */
1277                         err = nilfs_segctor_add_super_root(sci);
1278                         if (unlikely(err))
1279                                 break;
1280                 }
1281                 /* End of a logical segment */
1282                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1283                 nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1284                 return 0;
1285         case NILFS_ST_DSYNC:
1286  dsync_mode:
1287                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1288                 ii = sci->sc_dsync_inode;
1289                 if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1290                         break;
1291
1292                 err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1293                 if (unlikely(err))
1294                         break;
1295                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1296                 nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1297                 return 0;
1298         case NILFS_ST_DONE:
1299                 return 0;
1300         default:
1301                 BUG();
1302         }
1303
1304  break_or_fail:
1305         return err;
1306 }
1307
1308 /**
1309  * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1310  * @sci: nilfs_sc_info
1311  * @nilfs: nilfs object
1312  */
1313 static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1314                                             struct the_nilfs *nilfs)
1315 {
1316         struct nilfs_segment_buffer *segbuf, *prev;
1317         __u64 nextnum;
1318         int err, alloc = 0;
1319
1320         segbuf = nilfs_segbuf_new(sci->sc_super);
1321         if (unlikely(!segbuf))
1322                 return -ENOMEM;
1323
1324         if (list_empty(&sci->sc_write_logs)) {
1325                 nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1326                                  nilfs->ns_pseg_offset, nilfs);
1327                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1328                         nilfs_shift_to_next_segment(nilfs);
1329                         nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1330                 }
1331
1332                 segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1333                 nextnum = nilfs->ns_nextnum;
1334
1335                 if (nilfs->ns_segnum == nilfs->ns_nextnum)
1336                         /* Start from the head of a new full segment */
1337                         alloc++;
1338         } else {
1339                 /* Continue logs */
1340                 prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1341                 nilfs_segbuf_map_cont(segbuf, prev);
1342                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1343                 nextnum = prev->sb_nextnum;
1344
1345                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1346                         nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1347                         segbuf->sb_sum.seg_seq++;
1348                         alloc++;
1349                 }
1350         }
1351
1352         err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1353         if (err)
1354                 goto failed;
1355
1356         if (alloc) {
1357                 err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1358                 if (err)
1359                         goto failed;
1360         }
1361         nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1362
1363         BUG_ON(!list_empty(&sci->sc_segbufs));
1364         list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1365         sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1366         return 0;
1367
1368  failed:
1369         nilfs_segbuf_free(segbuf);
1370         return err;
1371 }
1372
1373 static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1374                                          struct the_nilfs *nilfs, int nadd)
1375 {
1376         struct nilfs_segment_buffer *segbuf, *prev;
1377         struct inode *sufile = nilfs->ns_sufile;
1378         __u64 nextnextnum;
1379         LIST_HEAD(list);
1380         int err, ret, i;
1381
1382         prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1383         /*
1384          * Since the segment specified with nextnum might be allocated during
1385          * the previous construction, the buffer including its segusage may
1386          * not be dirty.  The following call ensures that the buffer is dirty
1387          * and will pin the buffer on memory until the sufile is written.
1388          */
1389         err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1390         if (unlikely(err))
1391                 return err;
1392
1393         for (i = 0; i < nadd; i++) {
1394                 /* extend segment info */
1395                 err = -ENOMEM;
1396                 segbuf = nilfs_segbuf_new(sci->sc_super);
1397                 if (unlikely(!segbuf))
1398                         goto failed;
1399
1400                 /* map this buffer to region of segment on-disk */
1401                 nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1402                 sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1403
1404                 /* allocate the next next full segment */
1405                 err = nilfs_sufile_alloc(sufile, &nextnextnum);
1406                 if (unlikely(err))
1407                         goto failed_segbuf;
1408
1409                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1410                 nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1411
1412                 list_add_tail(&segbuf->sb_list, &list);
1413                 prev = segbuf;
1414         }
1415         list_splice_tail(&list, &sci->sc_segbufs);
1416         return 0;
1417
1418  failed_segbuf:
1419         nilfs_segbuf_free(segbuf);
1420  failed:
1421         list_for_each_entry(segbuf, &list, sb_list) {
1422                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1423                 WARN_ON(ret); /* never fails */
1424         }
1425         nilfs_destroy_logs(&list);
1426         return err;
1427 }
1428
1429 static void nilfs_free_incomplete_logs(struct list_head *logs,
1430                                        struct the_nilfs *nilfs)
1431 {
1432         struct nilfs_segment_buffer *segbuf, *prev;
1433         struct inode *sufile = nilfs->ns_sufile;
1434         int ret;
1435
1436         segbuf = NILFS_FIRST_SEGBUF(logs);
1437         if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1438                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1439                 WARN_ON(ret); /* never fails */
1440         }
1441         if (atomic_read(&segbuf->sb_err)) {
1442                 /* Case 1: The first segment failed */
1443                 if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1444                         /*
1445                          * Case 1a:  Partial segment appended into an existing
1446                          * segment
1447                          */
1448                         nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1449                                                 segbuf->sb_fseg_end);
1450                 else /* Case 1b:  New full segment */
1451                         set_nilfs_discontinued(nilfs);
1452         }
1453
1454         prev = segbuf;
1455         list_for_each_entry_continue(segbuf, logs, sb_list) {
1456                 if (prev->sb_nextnum != segbuf->sb_nextnum) {
1457                         ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1458                         WARN_ON(ret); /* never fails */
1459                 }
1460                 if (atomic_read(&segbuf->sb_err) &&
1461                     segbuf->sb_segnum != nilfs->ns_nextnum)
1462                         /* Case 2: extended segment (!= next) failed */
1463                         nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1464                 prev = segbuf;
1465         }
1466 }
1467
1468 static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1469                                           struct inode *sufile)
1470 {
1471         struct nilfs_segment_buffer *segbuf;
1472         unsigned long live_blocks;
1473         int ret;
1474
1475         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1476                 live_blocks = segbuf->sb_sum.nblocks +
1477                         (segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1478                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1479                                                      live_blocks,
1480                                                      sci->sc_seg_ctime);
1481                 WARN_ON(ret); /* always succeed because the segusage is dirty */
1482         }
1483 }
1484
1485 static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1486 {
1487         struct nilfs_segment_buffer *segbuf;
1488         int ret;
1489
1490         segbuf = NILFS_FIRST_SEGBUF(logs);
1491         ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1492                                              segbuf->sb_pseg_start -
1493                                              segbuf->sb_fseg_start, 0);
1494         WARN_ON(ret); /* always succeed because the segusage is dirty */
1495
1496         list_for_each_entry_continue(segbuf, logs, sb_list) {
1497                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1498                                                      0, 0);
1499                 WARN_ON(ret); /* always succeed */
1500         }
1501 }
1502
1503 static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1504                                             struct nilfs_segment_buffer *last,
1505                                             struct inode *sufile)
1506 {
1507         struct nilfs_segment_buffer *segbuf = last;
1508         int ret;
1509
1510         list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1511                 sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1512                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1513                 WARN_ON(ret);
1514         }
1515         nilfs_truncate_logs(&sci->sc_segbufs, last);
1516 }
1517
1518
1519 static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1520                                  struct the_nilfs *nilfs, int mode)
1521 {
1522         struct nilfs_cstage prev_stage = sci->sc_stage;
1523         int err, nadd = 1;
1524
1525         /* Collection retry loop */
1526         for (;;) {
1527                 sci->sc_nblk_this_inc = 0;
1528                 sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1529
1530                 err = nilfs_segctor_reset_segment_buffer(sci);
1531                 if (unlikely(err))
1532                         goto failed;
1533
1534                 err = nilfs_segctor_collect_blocks(sci, mode);
1535                 sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1536                 if (!err)
1537                         break;
1538
1539                 if (unlikely(err != -E2BIG))
1540                         goto failed;
1541
1542                 /* The current segment is filled up */
1543                 if (mode != SC_LSEG_SR ||
1544                     nilfs_sc_cstage_get(sci) < NILFS_ST_CPFILE)
1545                         break;
1546
1547                 nilfs_clear_logs(&sci->sc_segbufs);
1548
1549                 if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1550                         err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1551                                                         sci->sc_freesegs,
1552                                                         sci->sc_nfreesegs,
1553                                                         NULL);
1554                         WARN_ON(err); /* do not happen */
1555                         sci->sc_stage.flags &= ~NILFS_CF_SUFREED;
1556                 }
1557
1558                 err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1559                 if (unlikely(err))
1560                         return err;
1561
1562                 nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1563                 sci->sc_stage = prev_stage;
1564         }
1565         nilfs_segctor_zeropad_segsum(sci);
1566         nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1567         return 0;
1568
1569  failed:
1570         return err;
1571 }
1572
1573 static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1574                                       struct buffer_head *new_bh)
1575 {
1576         BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1577
1578         list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1579         /* The caller must release old_bh */
1580 }
1581
1582 static int
1583 nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1584                                      struct nilfs_segment_buffer *segbuf,
1585                                      int mode)
1586 {
1587         struct inode *inode = NULL;
1588         sector_t blocknr;
1589         unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1590         unsigned long nblocks = 0, ndatablk = 0;
1591         const struct nilfs_sc_operations *sc_op = NULL;
1592         struct nilfs_segsum_pointer ssp;
1593         struct nilfs_finfo *finfo = NULL;
1594         union nilfs_binfo binfo;
1595         struct buffer_head *bh, *bh_org;
1596         ino_t ino = 0;
1597         int err = 0;
1598
1599         if (!nfinfo)
1600                 goto out;
1601
1602         blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1603         ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1604         ssp.offset = sizeof(struct nilfs_segment_summary);
1605
1606         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1607                 if (bh == segbuf->sb_super_root)
1608                         break;
1609                 if (!finfo) {
1610                         finfo = nilfs_segctor_map_segsum_entry(
1611                                 sci, &ssp, sizeof(*finfo));
1612                         ino = le64_to_cpu(finfo->fi_ino);
1613                         nblocks = le32_to_cpu(finfo->fi_nblocks);
1614                         ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1615
1616                         inode = bh->b_folio->mapping->host;
1617
1618                         if (mode == SC_LSEG_DSYNC)
1619                                 sc_op = &nilfs_sc_dsync_ops;
1620                         else if (ino == NILFS_DAT_INO)
1621                                 sc_op = &nilfs_sc_dat_ops;
1622                         else /* file blocks */
1623                                 sc_op = &nilfs_sc_file_ops;
1624                 }
1625                 bh_org = bh;
1626                 get_bh(bh_org);
1627                 err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1628                                         &binfo);
1629                 if (bh != bh_org)
1630                         nilfs_list_replace_buffer(bh_org, bh);
1631                 brelse(bh_org);
1632                 if (unlikely(err))
1633                         goto failed_bmap;
1634
1635                 if (ndatablk > 0)
1636                         sc_op->write_data_binfo(sci, &ssp, &binfo);
1637                 else
1638                         sc_op->write_node_binfo(sci, &ssp, &binfo);
1639
1640                 blocknr++;
1641                 if (--nblocks == 0) {
1642                         finfo = NULL;
1643                         if (--nfinfo == 0)
1644                                 break;
1645                 } else if (ndatablk > 0)
1646                         ndatablk--;
1647         }
1648  out:
1649         return 0;
1650
1651  failed_bmap:
1652         return err;
1653 }
1654
1655 static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1656 {
1657         struct nilfs_segment_buffer *segbuf;
1658         int err;
1659
1660         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1661                 err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1662                 if (unlikely(err))
1663                         return err;
1664                 nilfs_segbuf_fill_in_segsum(segbuf);
1665         }
1666         return 0;
1667 }
1668
1669 static void nilfs_begin_page_io(struct page *page)
1670 {
1671         if (!page || PageWriteback(page))
1672                 /*
1673                  * For split b-tree node pages, this function may be called
1674                  * twice.  We ignore the 2nd or later calls by this check.
1675                  */
1676                 return;
1677
1678         lock_page(page);
1679         clear_page_dirty_for_io(page);
1680         set_page_writeback(page);
1681         unlock_page(page);
1682 }
1683
1684 static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci)
1685 {
1686         struct nilfs_segment_buffer *segbuf;
1687         struct page *bd_page = NULL, *fs_page = NULL;
1688
1689         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1690                 struct buffer_head *bh;
1691
1692                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1693                                     b_assoc_buffers) {
1694                         if (bh->b_page != bd_page) {
1695                                 if (bd_page) {
1696                                         lock_page(bd_page);
1697                                         clear_page_dirty_for_io(bd_page);
1698                                         set_page_writeback(bd_page);
1699                                         unlock_page(bd_page);
1700                                 }
1701                                 bd_page = bh->b_page;
1702                         }
1703                 }
1704
1705                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1706                                     b_assoc_buffers) {
1707                         set_buffer_async_write(bh);
1708                         if (bh == segbuf->sb_super_root) {
1709                                 if (bh->b_page != bd_page) {
1710                                         lock_page(bd_page);
1711                                         clear_page_dirty_for_io(bd_page);
1712                                         set_page_writeback(bd_page);
1713                                         unlock_page(bd_page);
1714                                         bd_page = bh->b_page;
1715                                 }
1716                                 break;
1717                         }
1718                         if (bh->b_page != fs_page) {
1719                                 nilfs_begin_page_io(fs_page);
1720                                 fs_page = bh->b_page;
1721                         }
1722                 }
1723         }
1724         if (bd_page) {
1725                 lock_page(bd_page);
1726                 clear_page_dirty_for_io(bd_page);
1727                 set_page_writeback(bd_page);
1728                 unlock_page(bd_page);
1729         }
1730         nilfs_begin_page_io(fs_page);
1731 }
1732
1733 static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1734                                struct the_nilfs *nilfs)
1735 {
1736         int ret;
1737
1738         ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1739         list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1740         return ret;
1741 }
1742
1743 static void nilfs_end_page_io(struct page *page, int err)
1744 {
1745         if (!page)
1746                 return;
1747
1748         if (buffer_nilfs_node(page_buffers(page)) && !PageWriteback(page)) {
1749                 /*
1750                  * For b-tree node pages, this function may be called twice
1751                  * or more because they might be split in a segment.
1752                  */
1753                 if (PageDirty(page)) {
1754                         /*
1755                          * For pages holding split b-tree node buffers, dirty
1756                          * flag on the buffers may be cleared discretely.
1757                          * In that case, the page is once redirtied for
1758                          * remaining buffers, and it must be cancelled if
1759                          * all the buffers get cleaned later.
1760                          */
1761                         lock_page(page);
1762                         if (nilfs_page_buffers_clean(page))
1763                                 __nilfs_clear_page_dirty(page);
1764                         unlock_page(page);
1765                 }
1766                 return;
1767         }
1768
1769         if (!err) {
1770                 if (!nilfs_page_buffers_clean(page))
1771                         __set_page_dirty_nobuffers(page);
1772                 ClearPageError(page);
1773         } else {
1774                 __set_page_dirty_nobuffers(page);
1775                 SetPageError(page);
1776         }
1777
1778         end_page_writeback(page);
1779 }
1780
1781 static void nilfs_abort_logs(struct list_head *logs, int err)
1782 {
1783         struct nilfs_segment_buffer *segbuf;
1784         struct page *bd_page = NULL, *fs_page = NULL;
1785         struct buffer_head *bh;
1786
1787         if (list_empty(logs))
1788                 return;
1789
1790         list_for_each_entry(segbuf, logs, sb_list) {
1791                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1792                                     b_assoc_buffers) {
1793                         clear_buffer_uptodate(bh);
1794                         if (bh->b_page != bd_page) {
1795                                 if (bd_page)
1796                                         end_page_writeback(bd_page);
1797                                 bd_page = bh->b_page;
1798                         }
1799                 }
1800
1801                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1802                                     b_assoc_buffers) {
1803                         clear_buffer_async_write(bh);
1804                         if (bh == segbuf->sb_super_root) {
1805                                 clear_buffer_uptodate(bh);
1806                                 if (bh->b_page != bd_page) {
1807                                         end_page_writeback(bd_page);
1808                                         bd_page = bh->b_page;
1809                                 }
1810                                 break;
1811                         }
1812                         if (bh->b_page != fs_page) {
1813                                 nilfs_end_page_io(fs_page, err);
1814                                 fs_page = bh->b_page;
1815                         }
1816                 }
1817         }
1818         if (bd_page)
1819                 end_page_writeback(bd_page);
1820
1821         nilfs_end_page_io(fs_page, err);
1822 }
1823
1824 static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
1825                                              struct the_nilfs *nilfs, int err)
1826 {
1827         LIST_HEAD(logs);
1828         int ret;
1829
1830         list_splice_tail_init(&sci->sc_write_logs, &logs);
1831         ret = nilfs_wait_on_logs(&logs);
1832         nilfs_abort_logs(&logs, ret ? : err);
1833
1834         list_splice_tail_init(&sci->sc_segbufs, &logs);
1835         nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
1836         nilfs_free_incomplete_logs(&logs, nilfs);
1837
1838         if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1839                 ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1840                                                 sci->sc_freesegs,
1841                                                 sci->sc_nfreesegs,
1842                                                 NULL);
1843                 WARN_ON(ret); /* do not happen */
1844         }
1845
1846         nilfs_destroy_logs(&logs);
1847 }
1848
1849 static void nilfs_set_next_segment(struct the_nilfs *nilfs,
1850                                    struct nilfs_segment_buffer *segbuf)
1851 {
1852         nilfs->ns_segnum = segbuf->sb_segnum;
1853         nilfs->ns_nextnum = segbuf->sb_nextnum;
1854         nilfs->ns_pseg_offset = segbuf->sb_pseg_start - segbuf->sb_fseg_start
1855                 + segbuf->sb_sum.nblocks;
1856         nilfs->ns_seg_seq = segbuf->sb_sum.seg_seq;
1857         nilfs->ns_ctime = segbuf->sb_sum.ctime;
1858 }
1859
1860 static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
1861 {
1862         struct nilfs_segment_buffer *segbuf;
1863         struct page *bd_page = NULL, *fs_page = NULL;
1864         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1865         int update_sr = false;
1866
1867         list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
1868                 struct buffer_head *bh;
1869
1870                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1871                                     b_assoc_buffers) {
1872                         set_buffer_uptodate(bh);
1873                         clear_buffer_dirty(bh);
1874                         if (bh->b_page != bd_page) {
1875                                 if (bd_page)
1876                                         end_page_writeback(bd_page);
1877                                 bd_page = bh->b_page;
1878                         }
1879                 }
1880                 /*
1881                  * We assume that the buffers which belong to the same page
1882                  * continue over the buffer list.
1883                  * Under this assumption, the last BHs of pages is
1884                  * identifiable by the discontinuity of bh->b_page
1885                  * (page != fs_page).
1886                  *
1887                  * For B-tree node blocks, however, this assumption is not
1888                  * guaranteed.  The cleanup code of B-tree node pages needs
1889                  * special care.
1890                  */
1891                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1892                                     b_assoc_buffers) {
1893                         const unsigned long set_bits = BIT(BH_Uptodate);
1894                         const unsigned long clear_bits =
1895                                 (BIT(BH_Dirty) | BIT(BH_Async_Write) |
1896                                  BIT(BH_Delay) | BIT(BH_NILFS_Volatile) |
1897                                  BIT(BH_NILFS_Redirected));
1898
1899                         set_mask_bits(&bh->b_state, clear_bits, set_bits);
1900                         if (bh == segbuf->sb_super_root) {
1901                                 if (bh->b_page != bd_page) {
1902                                         end_page_writeback(bd_page);
1903                                         bd_page = bh->b_page;
1904                                 }
1905                                 update_sr = true;
1906                                 break;
1907                         }
1908                         if (bh->b_page != fs_page) {
1909                                 nilfs_end_page_io(fs_page, 0);
1910                                 fs_page = bh->b_page;
1911                         }
1912                 }
1913
1914                 if (!nilfs_segbuf_simplex(segbuf)) {
1915                         if (segbuf->sb_sum.flags & NILFS_SS_LOGBGN) {
1916                                 set_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1917                                 sci->sc_lseg_stime = jiffies;
1918                         }
1919                         if (segbuf->sb_sum.flags & NILFS_SS_LOGEND)
1920                                 clear_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1921                 }
1922         }
1923         /*
1924          * Since pages may continue over multiple segment buffers,
1925          * end of the last page must be checked outside of the loop.
1926          */
1927         if (bd_page)
1928                 end_page_writeback(bd_page);
1929
1930         nilfs_end_page_io(fs_page, 0);
1931
1932         nilfs_drop_collected_inodes(&sci->sc_dirty_files);
1933
1934         if (nilfs_doing_gc())
1935                 nilfs_drop_collected_inodes(&sci->sc_gc_inodes);
1936         else
1937                 nilfs->ns_nongc_ctime = sci->sc_seg_ctime;
1938
1939         sci->sc_nblk_inc += sci->sc_nblk_this_inc;
1940
1941         segbuf = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1942         nilfs_set_next_segment(nilfs, segbuf);
1943
1944         if (update_sr) {
1945                 nilfs->ns_flushed_device = 0;
1946                 nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
1947                                        segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
1948
1949                 clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
1950                 clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1951                 set_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1952                 nilfs_segctor_clear_metadata_dirty(sci);
1953         } else
1954                 clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1955 }
1956
1957 static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
1958 {
1959         int ret;
1960
1961         ret = nilfs_wait_on_logs(&sci->sc_write_logs);
1962         if (!ret) {
1963                 nilfs_segctor_complete_write(sci);
1964                 nilfs_destroy_logs(&sci->sc_write_logs);
1965         }
1966         return ret;
1967 }
1968
1969 static int nilfs_segctor_collect_dirty_files(struct nilfs_sc_info *sci,
1970                                              struct the_nilfs *nilfs)
1971 {
1972         struct nilfs_inode_info *ii, *n;
1973         struct inode *ifile = sci->sc_root->ifile;
1974
1975         spin_lock(&nilfs->ns_inode_lock);
1976  retry:
1977         list_for_each_entry_safe(ii, n, &nilfs->ns_dirty_files, i_dirty) {
1978                 if (!ii->i_bh) {
1979                         struct buffer_head *ibh;
1980                         int err;
1981
1982                         spin_unlock(&nilfs->ns_inode_lock);
1983                         err = nilfs_ifile_get_inode_block(
1984                                 ifile, ii->vfs_inode.i_ino, &ibh);
1985                         if (unlikely(err)) {
1986                                 nilfs_warn(sci->sc_super,
1987                                            "log writer: error %d getting inode block (ino=%lu)",
1988                                            err, ii->vfs_inode.i_ino);
1989                                 return err;
1990                         }
1991                         spin_lock(&nilfs->ns_inode_lock);
1992                         if (likely(!ii->i_bh))
1993                                 ii->i_bh = ibh;
1994                         else
1995                                 brelse(ibh);
1996                         goto retry;
1997                 }
1998
1999                 // Always redirty the buffer to avoid race condition
2000                 mark_buffer_dirty(ii->i_bh);
2001                 nilfs_mdt_mark_dirty(ifile);
2002
2003                 clear_bit(NILFS_I_QUEUED, &ii->i_state);
2004                 set_bit(NILFS_I_BUSY, &ii->i_state);
2005                 list_move_tail(&ii->i_dirty, &sci->sc_dirty_files);
2006         }
2007         spin_unlock(&nilfs->ns_inode_lock);
2008
2009         return 0;
2010 }
2011
2012 static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
2013                                              struct the_nilfs *nilfs)
2014 {
2015         struct nilfs_inode_info *ii, *n;
2016         int during_mount = !(sci->sc_super->s_flags & SB_ACTIVE);
2017         int defer_iput = false;
2018
2019         spin_lock(&nilfs->ns_inode_lock);
2020         list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
2021                 if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
2022                     test_bit(NILFS_I_DIRTY, &ii->i_state))
2023                         continue;
2024
2025                 clear_bit(NILFS_I_BUSY, &ii->i_state);
2026                 brelse(ii->i_bh);
2027                 ii->i_bh = NULL;
2028                 list_del_init(&ii->i_dirty);
2029                 if (!ii->vfs_inode.i_nlink || during_mount) {
2030                         /*
2031                          * Defer calling iput() to avoid deadlocks if
2032                          * i_nlink == 0 or mount is not yet finished.
2033                          */
2034                         list_add_tail(&ii->i_dirty, &sci->sc_iput_queue);
2035                         defer_iput = true;
2036                 } else {
2037                         spin_unlock(&nilfs->ns_inode_lock);
2038                         iput(&ii->vfs_inode);
2039                         spin_lock(&nilfs->ns_inode_lock);
2040                 }
2041         }
2042         spin_unlock(&nilfs->ns_inode_lock);
2043
2044         if (defer_iput)
2045                 schedule_work(&sci->sc_iput_work);
2046 }
2047
2048 /*
2049  * Main procedure of segment constructor
2050  */
2051 static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
2052 {
2053         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2054         int err;
2055
2056         if (sb_rdonly(sci->sc_super))
2057                 return -EROFS;
2058
2059         nilfs_sc_cstage_set(sci, NILFS_ST_INIT);
2060         sci->sc_cno = nilfs->ns_cno;
2061
2062         err = nilfs_segctor_collect_dirty_files(sci, nilfs);
2063         if (unlikely(err))
2064                 goto out;
2065
2066         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
2067                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
2068
2069         if (nilfs_segctor_clean(sci))
2070                 goto out;
2071
2072         do {
2073                 sci->sc_stage.flags &= ~NILFS_CF_HISTORY_MASK;
2074
2075                 err = nilfs_segctor_begin_construction(sci, nilfs);
2076                 if (unlikely(err))
2077                         goto out;
2078
2079                 /* Update time stamp */
2080                 sci->sc_seg_ctime = ktime_get_real_seconds();
2081
2082                 err = nilfs_segctor_collect(sci, nilfs, mode);
2083                 if (unlikely(err))
2084                         goto failed;
2085
2086                 /* Avoid empty segment */
2087                 if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE &&
2088                     nilfs_segbuf_empty(sci->sc_curseg)) {
2089                         nilfs_segctor_abort_construction(sci, nilfs, 1);
2090                         goto out;
2091                 }
2092
2093                 err = nilfs_segctor_assign(sci, mode);
2094                 if (unlikely(err))
2095                         goto failed;
2096
2097                 if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2098                         nilfs_segctor_fill_in_file_bmap(sci);
2099
2100                 if (mode == SC_LSEG_SR &&
2101                     nilfs_sc_cstage_get(sci) >= NILFS_ST_CPFILE) {
2102                         err = nilfs_segctor_fill_in_checkpoint(sci);
2103                         if (unlikely(err))
2104                                 goto failed_to_write;
2105
2106                         nilfs_segctor_fill_in_super_root(sci, nilfs);
2107                 }
2108                 nilfs_segctor_update_segusage(sci, nilfs->ns_sufile);
2109
2110                 /* Write partial segments */
2111                 nilfs_segctor_prepare_write(sci);
2112
2113                 nilfs_add_checksums_on_logs(&sci->sc_segbufs,
2114                                             nilfs->ns_crc_seed);
2115
2116                 err = nilfs_segctor_write(sci, nilfs);
2117                 if (unlikely(err))
2118                         goto failed_to_write;
2119
2120                 if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE ||
2121                     nilfs->ns_blocksize_bits != PAGE_SHIFT) {
2122                         /*
2123                          * At this point, we avoid double buffering
2124                          * for blocksize < pagesize because page dirty
2125                          * flag is turned off during write and dirty
2126                          * buffers are not properly collected for
2127                          * pages crossing over segments.
2128                          */
2129                         err = nilfs_segctor_wait(sci);
2130                         if (err)
2131                                 goto failed_to_write;
2132                 }
2133         } while (nilfs_sc_cstage_get(sci) != NILFS_ST_DONE);
2134
2135  out:
2136         nilfs_segctor_drop_written_files(sci, nilfs);
2137         return err;
2138
2139  failed_to_write:
2140         if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2141                 nilfs_redirty_inodes(&sci->sc_dirty_files);
2142
2143  failed:
2144         if (nilfs_doing_gc())
2145                 nilfs_redirty_inodes(&sci->sc_gc_inodes);
2146         nilfs_segctor_abort_construction(sci, nilfs, err);
2147         goto out;
2148 }
2149
2150 /**
2151  * nilfs_segctor_start_timer - set timer of background write
2152  * @sci: nilfs_sc_info
2153  *
2154  * If the timer has already been set, it ignores the new request.
2155  * This function MUST be called within a section locking the segment
2156  * semaphore.
2157  */
2158 static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
2159 {
2160         spin_lock(&sci->sc_state_lock);
2161         if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
2162                 sci->sc_timer.expires = jiffies + sci->sc_interval;
2163                 add_timer(&sci->sc_timer);
2164                 sci->sc_state |= NILFS_SEGCTOR_COMMIT;
2165         }
2166         spin_unlock(&sci->sc_state_lock);
2167 }
2168
2169 static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
2170 {
2171         spin_lock(&sci->sc_state_lock);
2172         if (!(sci->sc_flush_request & BIT(bn))) {
2173                 unsigned long prev_req = sci->sc_flush_request;
2174
2175                 sci->sc_flush_request |= BIT(bn);
2176                 if (!prev_req)
2177                         wake_up(&sci->sc_wait_daemon);
2178         }
2179         spin_unlock(&sci->sc_state_lock);
2180 }
2181
2182 /**
2183  * nilfs_flush_segment - trigger a segment construction for resource control
2184  * @sb: super block
2185  * @ino: inode number of the file to be flushed out.
2186  */
2187 void nilfs_flush_segment(struct super_block *sb, ino_t ino)
2188 {
2189         struct the_nilfs *nilfs = sb->s_fs_info;
2190         struct nilfs_sc_info *sci = nilfs->ns_writer;
2191
2192         if (!sci || nilfs_doing_construction())
2193                 return;
2194         nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
2195                                         /* assign bit 0 to data files */
2196 }
2197
2198 struct nilfs_segctor_wait_request {
2199         wait_queue_entry_t      wq;
2200         __u32           seq;
2201         int             err;
2202         atomic_t        done;
2203 };
2204
2205 static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
2206 {
2207         struct nilfs_segctor_wait_request wait_req;
2208         int err = 0;
2209
2210         spin_lock(&sci->sc_state_lock);
2211         init_wait(&wait_req.wq);
2212         wait_req.err = 0;
2213         atomic_set(&wait_req.done, 0);
2214         wait_req.seq = ++sci->sc_seq_request;
2215         spin_unlock(&sci->sc_state_lock);
2216
2217         init_waitqueue_entry(&wait_req.wq, current);
2218         add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
2219         set_current_state(TASK_INTERRUPTIBLE);
2220         wake_up(&sci->sc_wait_daemon);
2221
2222         for (;;) {
2223                 if (atomic_read(&wait_req.done)) {
2224                         err = wait_req.err;
2225                         break;
2226                 }
2227                 if (!signal_pending(current)) {
2228                         schedule();
2229                         continue;
2230                 }
2231                 err = -ERESTARTSYS;
2232                 break;
2233         }
2234         finish_wait(&sci->sc_wait_request, &wait_req.wq);
2235         return err;
2236 }
2237
2238 static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
2239 {
2240         struct nilfs_segctor_wait_request *wrq, *n;
2241         unsigned long flags;
2242
2243         spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
2244         list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.head, wq.entry) {
2245                 if (!atomic_read(&wrq->done) &&
2246                     nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
2247                         wrq->err = err;
2248                         atomic_set(&wrq->done, 1);
2249                 }
2250                 if (atomic_read(&wrq->done)) {
2251                         wrq->wq.func(&wrq->wq,
2252                                      TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
2253                                      0, NULL);
2254                 }
2255         }
2256         spin_unlock_irqrestore(&sci->sc_wait_request.lock, flags);
2257 }
2258
2259 /**
2260  * nilfs_construct_segment - construct a logical segment
2261  * @sb: super block
2262  *
2263  * Return Value: On success, 0 is returned. On errors, one of the following
2264  * negative error code is returned.
2265  *
2266  * %-EROFS - Read only filesystem.
2267  *
2268  * %-EIO - I/O error
2269  *
2270  * %-ENOSPC - No space left on device (only in a panic state).
2271  *
2272  * %-ERESTARTSYS - Interrupted.
2273  *
2274  * %-ENOMEM - Insufficient memory available.
2275  */
2276 int nilfs_construct_segment(struct super_block *sb)
2277 {
2278         struct the_nilfs *nilfs = sb->s_fs_info;
2279         struct nilfs_sc_info *sci = nilfs->ns_writer;
2280         struct nilfs_transaction_info *ti;
2281
2282         if (sb_rdonly(sb) || unlikely(!sci))
2283                 return -EROFS;
2284
2285         /* A call inside transactions causes a deadlock. */
2286         BUG_ON((ti = current->journal_info) && ti->ti_magic == NILFS_TI_MAGIC);
2287
2288         return nilfs_segctor_sync(sci);
2289 }
2290
2291 /**
2292  * nilfs_construct_dsync_segment - construct a data-only logical segment
2293  * @sb: super block
2294  * @inode: inode whose data blocks should be written out
2295  * @start: start byte offset
2296  * @end: end byte offset (inclusive)
2297  *
2298  * Return Value: On success, 0 is returned. On errors, one of the following
2299  * negative error code is returned.
2300  *
2301  * %-EROFS - Read only filesystem.
2302  *
2303  * %-EIO - I/O error
2304  *
2305  * %-ENOSPC - No space left on device (only in a panic state).
2306  *
2307  * %-ERESTARTSYS - Interrupted.
2308  *
2309  * %-ENOMEM - Insufficient memory available.
2310  */
2311 int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
2312                                   loff_t start, loff_t end)
2313 {
2314         struct the_nilfs *nilfs = sb->s_fs_info;
2315         struct nilfs_sc_info *sci = nilfs->ns_writer;
2316         struct nilfs_inode_info *ii;
2317         struct nilfs_transaction_info ti;
2318         int err = 0;
2319
2320         if (sb_rdonly(sb) || unlikely(!sci))
2321                 return -EROFS;
2322
2323         nilfs_transaction_lock(sb, &ti, 0);
2324
2325         ii = NILFS_I(inode);
2326         if (test_bit(NILFS_I_INODE_SYNC, &ii->i_state) ||
2327             nilfs_test_opt(nilfs, STRICT_ORDER) ||
2328             test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2329             nilfs_discontinued(nilfs)) {
2330                 nilfs_transaction_unlock(sb);
2331                 err = nilfs_segctor_sync(sci);
2332                 return err;
2333         }
2334
2335         spin_lock(&nilfs->ns_inode_lock);
2336         if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
2337             !test_bit(NILFS_I_BUSY, &ii->i_state)) {
2338                 spin_unlock(&nilfs->ns_inode_lock);
2339                 nilfs_transaction_unlock(sb);
2340                 return 0;
2341         }
2342         spin_unlock(&nilfs->ns_inode_lock);
2343         sci->sc_dsync_inode = ii;
2344         sci->sc_dsync_start = start;
2345         sci->sc_dsync_end = end;
2346
2347         err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC);
2348         if (!err)
2349                 nilfs->ns_flushed_device = 0;
2350
2351         nilfs_transaction_unlock(sb);
2352         return err;
2353 }
2354
2355 #define FLUSH_FILE_BIT  (0x1) /* data file only */
2356 #define FLUSH_DAT_BIT   BIT(NILFS_DAT_INO) /* DAT only */
2357
2358 /**
2359  * nilfs_segctor_accept - record accepted sequence count of log-write requests
2360  * @sci: segment constructor object
2361  */
2362 static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
2363 {
2364         spin_lock(&sci->sc_state_lock);
2365         sci->sc_seq_accepted = sci->sc_seq_request;
2366         spin_unlock(&sci->sc_state_lock);
2367         del_timer_sync(&sci->sc_timer);
2368 }
2369
2370 /**
2371  * nilfs_segctor_notify - notify the result of request to caller threads
2372  * @sci: segment constructor object
2373  * @mode: mode of log forming
2374  * @err: error code to be notified
2375  */
2376 static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
2377 {
2378         /* Clear requests (even when the construction failed) */
2379         spin_lock(&sci->sc_state_lock);
2380
2381         if (mode == SC_LSEG_SR) {
2382                 sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
2383                 sci->sc_seq_done = sci->sc_seq_accepted;
2384                 nilfs_segctor_wakeup(sci, err);
2385                 sci->sc_flush_request = 0;
2386         } else {
2387                 if (mode == SC_FLUSH_FILE)
2388                         sci->sc_flush_request &= ~FLUSH_FILE_BIT;
2389                 else if (mode == SC_FLUSH_DAT)
2390                         sci->sc_flush_request &= ~FLUSH_DAT_BIT;
2391
2392                 /* re-enable timer if checkpoint creation was not done */
2393                 if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2394                     time_before(jiffies, sci->sc_timer.expires))
2395                         add_timer(&sci->sc_timer);
2396         }
2397         spin_unlock(&sci->sc_state_lock);
2398 }
2399
2400 /**
2401  * nilfs_segctor_construct - form logs and write them to disk
2402  * @sci: segment constructor object
2403  * @mode: mode of log forming
2404  */
2405 static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
2406 {
2407         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2408         struct nilfs_super_block **sbp;
2409         int err = 0;
2410
2411         nilfs_segctor_accept(sci);
2412
2413         if (nilfs_discontinued(nilfs))
2414                 mode = SC_LSEG_SR;
2415         if (!nilfs_segctor_confirm(sci))
2416                 err = nilfs_segctor_do_construct(sci, mode);
2417
2418         if (likely(!err)) {
2419                 if (mode != SC_FLUSH_DAT)
2420                         atomic_set(&nilfs->ns_ndirtyblks, 0);
2421                 if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
2422                     nilfs_discontinued(nilfs)) {
2423                         down_write(&nilfs->ns_sem);
2424                         err = -EIO;
2425                         sbp = nilfs_prepare_super(sci->sc_super,
2426                                                   nilfs_sb_will_flip(nilfs));
2427                         if (likely(sbp)) {
2428                                 nilfs_set_log_cursor(sbp[0], nilfs);
2429                                 err = nilfs_commit_super(sci->sc_super,
2430                                                          NILFS_SB_COMMIT);
2431                         }
2432                         up_write(&nilfs->ns_sem);
2433                 }
2434         }
2435
2436         nilfs_segctor_notify(sci, mode, err);
2437         return err;
2438 }
2439
2440 static void nilfs_construction_timeout(struct timer_list *t)
2441 {
2442         struct nilfs_sc_info *sci = from_timer(sci, t, sc_timer);
2443
2444         wake_up_process(sci->sc_timer_task);
2445 }
2446
2447 static void
2448 nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
2449 {
2450         struct nilfs_inode_info *ii, *n;
2451
2452         list_for_each_entry_safe(ii, n, head, i_dirty) {
2453                 if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
2454                         continue;
2455                 list_del_init(&ii->i_dirty);
2456                 truncate_inode_pages(&ii->vfs_inode.i_data, 0);
2457                 nilfs_btnode_cache_clear(ii->i_assoc_inode->i_mapping);
2458                 iput(&ii->vfs_inode);
2459         }
2460 }
2461
2462 int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
2463                          void **kbufs)
2464 {
2465         struct the_nilfs *nilfs = sb->s_fs_info;
2466         struct nilfs_sc_info *sci = nilfs->ns_writer;
2467         struct nilfs_transaction_info ti;
2468         int err;
2469
2470         if (unlikely(!sci))
2471                 return -EROFS;
2472
2473         nilfs_transaction_lock(sb, &ti, 1);
2474
2475         err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
2476         if (unlikely(err))
2477                 goto out_unlock;
2478
2479         err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
2480         if (unlikely(err)) {
2481                 nilfs_mdt_restore_from_shadow_map(nilfs->ns_dat);
2482                 goto out_unlock;
2483         }
2484
2485         sci->sc_freesegs = kbufs[4];
2486         sci->sc_nfreesegs = argv[4].v_nmembs;
2487         list_splice_tail_init(&nilfs->ns_gc_inodes, &sci->sc_gc_inodes);
2488
2489         for (;;) {
2490                 err = nilfs_segctor_construct(sci, SC_LSEG_SR);
2491                 nilfs_remove_written_gcinodes(nilfs, &sci->sc_gc_inodes);
2492
2493                 if (likely(!err))
2494                         break;
2495
2496                 nilfs_warn(sb, "error %d cleaning segments", err);
2497                 set_current_state(TASK_INTERRUPTIBLE);
2498                 schedule_timeout(sci->sc_interval);
2499         }
2500         if (nilfs_test_opt(nilfs, DISCARD)) {
2501                 int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
2502                                                  sci->sc_nfreesegs);
2503                 if (ret) {
2504                         nilfs_warn(sb,
2505                                    "error %d on discard request, turning discards off for the device",
2506                                    ret);
2507                         nilfs_clear_opt(nilfs, DISCARD);
2508                 }
2509         }
2510
2511  out_unlock:
2512         sci->sc_freesegs = NULL;
2513         sci->sc_nfreesegs = 0;
2514         nilfs_mdt_clear_shadow_map(nilfs->ns_dat);
2515         nilfs_transaction_unlock(sb);
2516         return err;
2517 }
2518
2519 static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
2520 {
2521         struct nilfs_transaction_info ti;
2522
2523         nilfs_transaction_lock(sci->sc_super, &ti, 0);
2524         nilfs_segctor_construct(sci, mode);
2525
2526         /*
2527          * Unclosed segment should be retried.  We do this using sc_timer.
2528          * Timeout of sc_timer will invoke complete construction which leads
2529          * to close the current logical segment.
2530          */
2531         if (test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags))
2532                 nilfs_segctor_start_timer(sci);
2533
2534         nilfs_transaction_unlock(sci->sc_super);
2535 }
2536
2537 static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
2538 {
2539         int mode = 0;
2540
2541         spin_lock(&sci->sc_state_lock);
2542         mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
2543                 SC_FLUSH_DAT : SC_FLUSH_FILE;
2544         spin_unlock(&sci->sc_state_lock);
2545
2546         if (mode) {
2547                 nilfs_segctor_do_construct(sci, mode);
2548
2549                 spin_lock(&sci->sc_state_lock);
2550                 sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
2551                         ~FLUSH_FILE_BIT : ~FLUSH_DAT_BIT;
2552                 spin_unlock(&sci->sc_state_lock);
2553         }
2554         clear_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
2555 }
2556
2557 static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
2558 {
2559         if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2560             time_before(jiffies, sci->sc_lseg_stime + sci->sc_mjcp_freq)) {
2561                 if (!(sci->sc_flush_request & ~FLUSH_FILE_BIT))
2562                         return SC_FLUSH_FILE;
2563                 else if (!(sci->sc_flush_request & ~FLUSH_DAT_BIT))
2564                         return SC_FLUSH_DAT;
2565         }
2566         return SC_LSEG_SR;
2567 }
2568
2569 /**
2570  * nilfs_segctor_thread - main loop of the segment constructor thread.
2571  * @arg: pointer to a struct nilfs_sc_info.
2572  *
2573  * nilfs_segctor_thread() initializes a timer and serves as a daemon
2574  * to execute segment constructions.
2575  */
2576 static int nilfs_segctor_thread(void *arg)
2577 {
2578         struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
2579         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2580         int timeout = 0;
2581
2582         sci->sc_timer_task = current;
2583
2584         /* start sync. */
2585         sci->sc_task = current;
2586         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_start_thread() */
2587         nilfs_info(sci->sc_super,
2588                    "segctord starting. Construction interval = %lu seconds, CP frequency < %lu seconds",
2589                    sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
2590
2591         spin_lock(&sci->sc_state_lock);
2592  loop:
2593         for (;;) {
2594                 int mode;
2595
2596                 if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2597                         goto end_thread;
2598
2599                 if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2600                         mode = SC_LSEG_SR;
2601                 else if (sci->sc_flush_request)
2602                         mode = nilfs_segctor_flush_mode(sci);
2603                 else
2604                         break;
2605
2606                 spin_unlock(&sci->sc_state_lock);
2607                 nilfs_segctor_thread_construct(sci, mode);
2608                 spin_lock(&sci->sc_state_lock);
2609                 timeout = 0;
2610         }
2611
2612
2613         if (freezing(current)) {
2614                 spin_unlock(&sci->sc_state_lock);
2615                 try_to_freeze();
2616                 spin_lock(&sci->sc_state_lock);
2617         } else {
2618                 DEFINE_WAIT(wait);
2619                 int should_sleep = 1;
2620
2621                 prepare_to_wait(&sci->sc_wait_daemon, &wait,
2622                                 TASK_INTERRUPTIBLE);
2623
2624                 if (sci->sc_seq_request != sci->sc_seq_done)
2625                         should_sleep = 0;
2626                 else if (sci->sc_flush_request)
2627                         should_sleep = 0;
2628                 else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2629                         should_sleep = time_before(jiffies,
2630                                         sci->sc_timer.expires);
2631
2632                 if (should_sleep) {
2633                         spin_unlock(&sci->sc_state_lock);
2634                         schedule();
2635                         spin_lock(&sci->sc_state_lock);
2636                 }
2637                 finish_wait(&sci->sc_wait_daemon, &wait);
2638                 timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2639                            time_after_eq(jiffies, sci->sc_timer.expires));
2640
2641                 if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2642                         set_nilfs_discontinued(nilfs);
2643         }
2644         goto loop;
2645
2646  end_thread:
2647         /* end sync. */
2648         sci->sc_task = NULL;
2649         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
2650         spin_unlock(&sci->sc_state_lock);
2651         return 0;
2652 }
2653
2654 static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2655 {
2656         struct task_struct *t;
2657
2658         t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2659         if (IS_ERR(t)) {
2660                 int err = PTR_ERR(t);
2661
2662                 nilfs_err(sci->sc_super, "error %d creating segctord thread",
2663                           err);
2664                 return err;
2665         }
2666         wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2667         return 0;
2668 }
2669
2670 static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2671         __acquires(&sci->sc_state_lock)
2672         __releases(&sci->sc_state_lock)
2673 {
2674         sci->sc_state |= NILFS_SEGCTOR_QUIT;
2675
2676         while (sci->sc_task) {
2677                 wake_up(&sci->sc_wait_daemon);
2678                 spin_unlock(&sci->sc_state_lock);
2679                 wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2680                 spin_lock(&sci->sc_state_lock);
2681         }
2682 }
2683
2684 /*
2685  * Setup & clean-up functions
2686  */
2687 static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
2688                                                struct nilfs_root *root)
2689 {
2690         struct the_nilfs *nilfs = sb->s_fs_info;
2691         struct nilfs_sc_info *sci;
2692
2693         sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2694         if (!sci)
2695                 return NULL;
2696
2697         sci->sc_super = sb;
2698
2699         nilfs_get_root(root);
2700         sci->sc_root = root;
2701
2702         init_waitqueue_head(&sci->sc_wait_request);
2703         init_waitqueue_head(&sci->sc_wait_daemon);
2704         init_waitqueue_head(&sci->sc_wait_task);
2705         spin_lock_init(&sci->sc_state_lock);
2706         INIT_LIST_HEAD(&sci->sc_dirty_files);
2707         INIT_LIST_HEAD(&sci->sc_segbufs);
2708         INIT_LIST_HEAD(&sci->sc_write_logs);
2709         INIT_LIST_HEAD(&sci->sc_gc_inodes);
2710         INIT_LIST_HEAD(&sci->sc_iput_queue);
2711         INIT_WORK(&sci->sc_iput_work, nilfs_iput_work_func);
2712         timer_setup(&sci->sc_timer, nilfs_construction_timeout, 0);
2713
2714         sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2715         sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2716         sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2717
2718         if (nilfs->ns_interval)
2719                 sci->sc_interval = HZ * nilfs->ns_interval;
2720         if (nilfs->ns_watermark)
2721                 sci->sc_watermark = nilfs->ns_watermark;
2722         return sci;
2723 }
2724
2725 static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2726 {
2727         int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2728
2729         /*
2730          * The segctord thread was stopped and its timer was removed.
2731          * But some tasks remain.
2732          */
2733         do {
2734                 struct nilfs_transaction_info ti;
2735
2736                 nilfs_transaction_lock(sci->sc_super, &ti, 0);
2737                 ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2738                 nilfs_transaction_unlock(sci->sc_super);
2739
2740                 flush_work(&sci->sc_iput_work);
2741
2742         } while (ret && ret != -EROFS && retrycount-- > 0);
2743 }
2744
2745 /**
2746  * nilfs_segctor_destroy - destroy the segment constructor.
2747  * @sci: nilfs_sc_info
2748  *
2749  * nilfs_segctor_destroy() kills the segctord thread and frees
2750  * the nilfs_sc_info struct.
2751  * Caller must hold the segment semaphore.
2752  */
2753 static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2754 {
2755         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2756         int flag;
2757
2758         up_write(&nilfs->ns_segctor_sem);
2759
2760         spin_lock(&sci->sc_state_lock);
2761         nilfs_segctor_kill_thread(sci);
2762         flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2763                 || sci->sc_seq_request != sci->sc_seq_done);
2764         spin_unlock(&sci->sc_state_lock);
2765
2766         if (flush_work(&sci->sc_iput_work))
2767                 flag = true;
2768
2769         if (flag || !nilfs_segctor_confirm(sci))
2770                 nilfs_segctor_write_out(sci);
2771
2772         if (!list_empty(&sci->sc_dirty_files)) {
2773                 nilfs_warn(sci->sc_super,
2774                            "disposed unprocessed dirty file(s) when stopping log writer");
2775                 nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2776         }
2777
2778         if (!list_empty(&sci->sc_iput_queue)) {
2779                 nilfs_warn(sci->sc_super,
2780                            "disposed unprocessed inode(s) in iput queue when stopping log writer");
2781                 nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 1);
2782         }
2783
2784         WARN_ON(!list_empty(&sci->sc_segbufs));
2785         WARN_ON(!list_empty(&sci->sc_write_logs));
2786
2787         nilfs_put_root(sci->sc_root);
2788
2789         down_write(&nilfs->ns_segctor_sem);
2790
2791         timer_shutdown_sync(&sci->sc_timer);
2792         kfree(sci);
2793 }
2794
2795 /**
2796  * nilfs_attach_log_writer - attach log writer
2797  * @sb: super block instance
2798  * @root: root object of the current filesystem tree
2799  *
2800  * This allocates a log writer object, initializes it, and starts the
2801  * log writer.
2802  *
2803  * Return Value: On success, 0 is returned. On error, one of the following
2804  * negative error code is returned.
2805  *
2806  * %-ENOMEM - Insufficient memory available.
2807  */
2808 int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
2809 {
2810         struct the_nilfs *nilfs = sb->s_fs_info;
2811         int err;
2812
2813         if (nilfs->ns_writer) {
2814                 /*
2815                  * This happens if the filesystem is made read-only by
2816                  * __nilfs_error or nilfs_remount and then remounted
2817                  * read/write.  In these cases, reuse the existing
2818                  * writer.
2819                  */
2820                 return 0;
2821         }
2822
2823         nilfs->ns_writer = nilfs_segctor_new(sb, root);
2824         if (!nilfs->ns_writer)
2825                 return -ENOMEM;
2826
2827         inode_attach_wb(nilfs->ns_bdev->bd_inode, NULL);
2828
2829         err = nilfs_segctor_start_thread(nilfs->ns_writer);
2830         if (unlikely(err))
2831                 nilfs_detach_log_writer(sb);
2832
2833         return err;
2834 }
2835
2836 /**
2837  * nilfs_detach_log_writer - destroy log writer
2838  * @sb: super block instance
2839  *
2840  * This kills log writer daemon, frees the log writer object, and
2841  * destroys list of dirty files.
2842  */
2843 void nilfs_detach_log_writer(struct super_block *sb)
2844 {
2845         struct the_nilfs *nilfs = sb->s_fs_info;
2846         LIST_HEAD(garbage_list);
2847
2848         down_write(&nilfs->ns_segctor_sem);
2849         if (nilfs->ns_writer) {
2850                 nilfs_segctor_destroy(nilfs->ns_writer);
2851                 nilfs->ns_writer = NULL;
2852         }
2853         set_nilfs_purging(nilfs);
2854
2855         /* Force to free the list of dirty files */
2856         spin_lock(&nilfs->ns_inode_lock);
2857         if (!list_empty(&nilfs->ns_dirty_files)) {
2858                 list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2859                 nilfs_warn(sb,
2860                            "disposed unprocessed dirty file(s) when detaching log writer");
2861         }
2862         spin_unlock(&nilfs->ns_inode_lock);
2863         up_write(&nilfs->ns_segctor_sem);
2864
2865         nilfs_dispose_list(nilfs, &garbage_list, 1);
2866         clear_nilfs_purging(nilfs);
2867 }