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 static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
 434 {
 435         sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
 436         if (NILFS_SEGBUF_IS_LAST(sci->sc_curseg, &sci->sc_segbufs))
 437                 return -E2BIG; /*
 438                                 * The current segment is filled up
 439                                 * (internal code)
 440                                 */
 441         sci->sc_curseg = NILFS_NEXT_SEGBUF(sci->sc_curseg);
 442         return nilfs_segctor_reset_segment_buffer(sci);
 443 }
 444
 445 static int nilfs_segctor_add_super_root(struct nilfs_sc_info *sci)
 446 {
 447         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 448         int err;
 449
 450         if (segbuf->sb_sum.nblocks >= segbuf->sb_rest_blocks) {
 451                 err = nilfs_segctor_feed_segment(sci);
 452                 if (err)
 453                         return err;
 454                 segbuf = sci->sc_curseg;
 455         }
 456         err = nilfs_segbuf_extend_payload(segbuf, &segbuf->sb_super_root);
 457         if (likely(!err))
 458                 segbuf->sb_sum.flags |= NILFS_SS_SR;
 459         return err;
 460 }
 461
 462 /*
 463  * Functions for making segment summary and payloads
 464  */
 465 static int nilfs_segctor_segsum_block_required(
 466         struct nilfs_sc_info *sci, const struct nilfs_segsum_pointer *ssp,
 467         unsigned int binfo_size)
 468 {
 469         unsigned int blocksize = sci->sc_super->s_blocksize;
 470         /* Size of finfo and binfo is enough small against blocksize */
 471
 472         return ssp->offset + binfo_size +
 473                 (!sci->sc_blk_cnt ? sizeof(struct nilfs_finfo) : 0) >
 474                 blocksize;
 475 }
 476
 477 static void nilfs_segctor_begin_finfo(struct nilfs_sc_info *sci,
 478                                       struct inode *inode)
 479 {
 480         sci->sc_curseg->sb_sum.nfinfo++;
 481         sci->sc_binfo_ptr = sci->sc_finfo_ptr;
 482         nilfs_segctor_map_segsum_entry(
 483                 sci, &sci->sc_binfo_ptr, sizeof(struct nilfs_finfo));
 484
 485         if (NILFS_I(inode)->i_root &&
 486             !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 487                 set_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
 488         /* skip finfo */
 489 }
 490
 491 static void nilfs_segctor_end_finfo(struct nilfs_sc_info *sci,
 492                                     struct inode *inode)
 493 {
 494         struct nilfs_finfo *finfo;
 495         struct nilfs_inode_info *ii;
 496         struct nilfs_segment_buffer *segbuf;
 497         __u64 cno;
 498
 499         if (sci->sc_blk_cnt == 0)
 500                 return;
 501
 502         ii = NILFS_I(inode);
 503
 504         if (test_bit(NILFS_I_GCINODE, &ii->i_state))
 505                 cno = ii->i_cno;
 506         else if (NILFS_ROOT_METADATA_FILE(inode->i_ino))
 507                 cno = 0;
 508         else
 509                 cno = sci->sc_cno;
 510
 511         finfo = nilfs_segctor_map_segsum_entry(sci, &sci->sc_finfo_ptr,
 512                                                  sizeof(*finfo));
 513         finfo->fi_ino = cpu_to_le64(inode->i_ino);
 514         finfo->fi_nblocks = cpu_to_le32(sci->sc_blk_cnt);
 515         finfo->fi_ndatablk = cpu_to_le32(sci->sc_datablk_cnt);
 516         finfo->fi_cno = cpu_to_le64(cno);
 517
 518         segbuf = sci->sc_curseg;
 519         segbuf->sb_sum.sumbytes = sci->sc_binfo_ptr.offset +
 520                 sci->sc_super->s_blocksize * (segbuf->sb_sum.nsumblk - 1);
 521         sci->sc_finfo_ptr = sci->sc_binfo_ptr;
 522         sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 523 }
 524
 525 static int nilfs_segctor_add_file_block(struct nilfs_sc_info *sci,
 526                                         struct buffer_head *bh,
 527                                         struct inode *inode,
 528                                         unsigned int binfo_size)
 529 {
 530         struct nilfs_segment_buffer *segbuf;
 531         int required, err = 0;
 532
 533  retry:
 534         segbuf = sci->sc_curseg;
 535         required = nilfs_segctor_segsum_block_required(
 536                 sci, &sci->sc_binfo_ptr, binfo_size);
 537         if (segbuf->sb_sum.nblocks + required + 1 > segbuf->sb_rest_blocks) {
 538                 nilfs_segctor_end_finfo(sci, inode);
 539                 err = nilfs_segctor_feed_segment(sci);
 540                 if (err)
 541                         return err;
 542                 goto retry;
 543         }
 544         if (unlikely(required)) {
 545                 err = nilfs_segbuf_extend_segsum(segbuf);
 546                 if (unlikely(err))
 547                         goto failed;
 548         }
 549         if (sci->sc_blk_cnt == 0)
 550                 nilfs_segctor_begin_finfo(sci, inode);
 551
 552         nilfs_segctor_map_segsum_entry(sci, &sci->sc_binfo_ptr, binfo_size);
 553         /* Substitution to vblocknr is delayed until update_blocknr() */
 554         nilfs_segbuf_add_file_buffer(segbuf, bh);
 555         sci->sc_blk_cnt++;
 556  failed:
 557         return err;
 558 }
 559
 560 /*
 561  * Callback functions that enumerate, mark, and collect dirty blocks
 562  */
 563 static int nilfs_collect_file_data(struct nilfs_sc_info *sci,
 564                                    struct buffer_head *bh, struct inode *inode)
 565 {
 566         int err;
 567
 568         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 569         if (err < 0)
 570                 return err;
 571
 572         err = nilfs_segctor_add_file_block(sci, bh, inode,
 573                                            sizeof(struct nilfs_binfo_v));
 574         if (!err)
 575                 sci->sc_datablk_cnt++;
 576         return err;
 577 }
 578
 579 static int nilfs_collect_file_node(struct nilfs_sc_info *sci,
 580                                    struct buffer_head *bh,
 581                                    struct inode *inode)
 582 {
 583         return nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 584 }
 585
 586 static int nilfs_collect_file_bmap(struct nilfs_sc_info *sci,
 587                                    struct buffer_head *bh,
 588                                    struct inode *inode)
 589 {
 590         WARN_ON(!buffer_dirty(bh));
 591         return nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 592 }
 593
 594 static void nilfs_write_file_data_binfo(struct nilfs_sc_info *sci,
 595                                         struct nilfs_segsum_pointer *ssp,
 596                                         union nilfs_binfo *binfo)
 597 {
 598         struct nilfs_binfo_v *binfo_v = nilfs_segctor_map_segsum_entry(
 599                 sci, ssp, sizeof(*binfo_v));
 600         *binfo_v = binfo->bi_v;
 601 }
 602
 603 static void nilfs_write_file_node_binfo(struct nilfs_sc_info *sci,
 604                                         struct nilfs_segsum_pointer *ssp,
 605                                         union nilfs_binfo *binfo)
 606 {
 607         __le64 *vblocknr = nilfs_segctor_map_segsum_entry(
 608                 sci, ssp, sizeof(*vblocknr));
 609         *vblocknr = binfo->bi_v.bi_vblocknr;
 610 }
 611
 612 static const struct nilfs_sc_operations nilfs_sc_file_ops = {
 613         .collect_data = nilfs_collect_file_data,
 614         .collect_node = nilfs_collect_file_node,
 615         .collect_bmap = nilfs_collect_file_bmap,
 616         .write_data_binfo = nilfs_write_file_data_binfo,
 617         .write_node_binfo = nilfs_write_file_node_binfo,
 618 };
 619
 620 static int nilfs_collect_dat_data(struct nilfs_sc_info *sci,
 621                                   struct buffer_head *bh, struct inode *inode)
 622 {
 623         int err;
 624
 625         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 626         if (err < 0)
 627                 return err;
 628
 629         err = nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 630         if (!err)
 631                 sci->sc_datablk_cnt++;
 632         return err;
 633 }
 634
 635 static int nilfs_collect_dat_bmap(struct nilfs_sc_info *sci,
 636                                   struct buffer_head *bh, struct inode *inode)
 637 {
 638         WARN_ON(!buffer_dirty(bh));
 639         return nilfs_segctor_add_file_block(sci, bh, inode,
 640                                             sizeof(struct nilfs_binfo_dat));
 641 }
 642
 643 static void nilfs_write_dat_data_binfo(struct nilfs_sc_info *sci,
 644                                        struct nilfs_segsum_pointer *ssp,
 645                                        union nilfs_binfo *binfo)
 646 {
 647         __le64 *blkoff = nilfs_segctor_map_segsum_entry(sci, ssp,
 648                                                           sizeof(*blkoff));
 649         *blkoff = binfo->bi_dat.bi_blkoff;
 650 }
 651
 652 static void nilfs_write_dat_node_binfo(struct nilfs_sc_info *sci,
 653                                        struct nilfs_segsum_pointer *ssp,
 654                                        union nilfs_binfo *binfo)
 655 {
 656         struct nilfs_binfo_dat *binfo_dat =
 657                 nilfs_segctor_map_segsum_entry(sci, ssp, sizeof(*binfo_dat));
 658         *binfo_dat = binfo->bi_dat;
 659 }
 660
 661 static const struct nilfs_sc_operations nilfs_sc_dat_ops = {
 662         .collect_data = nilfs_collect_dat_data,
 663         .collect_node = nilfs_collect_file_node,
 664         .collect_bmap = nilfs_collect_dat_bmap,
 665         .write_data_binfo = nilfs_write_dat_data_binfo,
 666         .write_node_binfo = nilfs_write_dat_node_binfo,
 667 };
 668
 669 static const struct nilfs_sc_operations nilfs_sc_dsync_ops = {
 670         .collect_data = nilfs_collect_file_data,
 671         .collect_node = NULL,
 672         .collect_bmap = NULL,
 673         .write_data_binfo = nilfs_write_file_data_binfo,
 674         .write_node_binfo = NULL,
 675 };
 676
 677 static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode,
 678                                               struct list_head *listp,
 679                                               size_t nlimit,
 680                                               loff_t start, loff_t end)
 681 {
 682         struct address_space *mapping = inode->i_mapping;
 683         struct folio_batch fbatch;
 684         pgoff_t index = 0, last = ULONG_MAX;
 685         size_t ndirties = 0;
 686         int i;
 687
 688         if (unlikely(start != 0 || end != LLONG_MAX)) {
 689                 /*
 690                  * A valid range is given for sync-ing data pages. The
 691                  * range is rounded to per-page; extra dirty buffers
 692                  * may be included if blocksize < pagesize.
 693                  */
 694                 index = start >> PAGE_SHIFT;
 695                 last = end >> PAGE_SHIFT;
 696         }
 697         folio_batch_init(&fbatch);
 698  repeat:
 699         if (unlikely(index > last) ||
 700               !filemap_get_folios_tag(mapping, &index, last,
 701                       PAGECACHE_TAG_DIRTY, &fbatch))
 702                 return ndirties;
 703
 704         for (i = 0; i < folio_batch_count(&fbatch); i++) {
 705                 struct buffer_head *bh, *head;
 706                 struct folio *folio = fbatch.folios[i];
 707
 708                 folio_lock(folio);
 709                 head = folio_buffers(folio);
 710                 if (!head) {
 711                         create_empty_buffers(&folio->page, i_blocksize(inode), 0);
 712                         head = folio_buffers(folio);
 713                 }
 714                 folio_unlock(folio);
 715
 716                 bh = head;
 717                 do {
 718                         if (!buffer_dirty(bh) || buffer_async_write(bh))
 719                                 continue;
 720                         get_bh(bh);
 721                         list_add_tail(&bh->b_assoc_buffers, listp);
 722                         ndirties++;
 723                         if (unlikely(ndirties >= nlimit)) {
 724                                 folio_batch_release(&fbatch);
 725                                 cond_resched();
 726                                 return ndirties;
 727                         }
 728                 } while (bh = bh->b_this_page, bh != head);
 729         }
 730         folio_batch_release(&fbatch);
 731         cond_resched();
 732         goto repeat;
 733 }
 734
 735 static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
 736                                             struct list_head *listp)
 737 {
 738         struct nilfs_inode_info *ii = NILFS_I(inode);
 739         struct inode *btnc_inode = ii->i_assoc_inode;
 740         struct folio_batch fbatch;
 741         struct buffer_head *bh, *head;
 742         unsigned int i;
 743         pgoff_t index = 0;
 744
 745         if (!btnc_inode)
 746                 return;
 747         folio_batch_init(&fbatch);
 748
 749         while (filemap_get_folios_tag(btnc_inode->i_mapping, &index,
 750                                 (pgoff_t)-1, PAGECACHE_TAG_DIRTY, &fbatch)) {
 751                 for (i = 0; i < folio_batch_count(&fbatch); i++) {
 752                         bh = head = folio_buffers(fbatch.folios[i]);
 753                         do {
 754                                 if (buffer_dirty(bh) &&
 755                                                 !buffer_async_write(bh)) {
 756                                         get_bh(bh);
 757                                         list_add_tail(&bh->b_assoc_buffers,
 758                                                       listp);
 759                                 }
 760                                 bh = bh->b_this_page;
 761                         } while (bh != head);
 762                 }
 763                 folio_batch_release(&fbatch);
 764                 cond_resched();
 765         }
 766 }
 767
 768 static void nilfs_dispose_list(struct the_nilfs *nilfs,
 769                                struct list_head *head, int force)
 770 {
 771         struct nilfs_inode_info *ii, *n;
 772         struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
 773         unsigned int nv = 0;
 774
 775         while (!list_empty(head)) {
 776                 spin_lock(&nilfs->ns_inode_lock);
 777                 list_for_each_entry_safe(ii, n, head, i_dirty) {
 778                         list_del_init(&ii->i_dirty);
 779                         if (force) {
 780                                 if (unlikely(ii->i_bh)) {
 781                                         brelse(ii->i_bh);
 782                                         ii->i_bh = NULL;
 783                                 }
 784                         } else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
 785                                 set_bit(NILFS_I_QUEUED, &ii->i_state);
 786                                 list_add_tail(&ii->i_dirty,
 787                                               &nilfs->ns_dirty_files);
 788                                 continue;
 789                         }
 790                         ivec[nv++] = ii;
 791                         if (nv == SC_N_INODEVEC)
 792                                 break;
 793                 }
 794                 spin_unlock(&nilfs->ns_inode_lock);
 795
 796                 for (pii = ivec; nv > 0; pii++, nv--)
 797                         iput(&(*pii)->vfs_inode);
 798         }
 799 }
 800
 801 static void nilfs_iput_work_func(struct work_struct *work)
 802 {
 803         struct nilfs_sc_info *sci = container_of(work, struct nilfs_sc_info,
 804                                                  sc_iput_work);
 805         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 806
 807         nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 0);
 808 }
 809
 810 static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
 811                                      struct nilfs_root *root)
 812 {
 813         int ret = 0;
 814
 815         if (nilfs_mdt_fetch_dirty(root->ifile))
 816                 ret++;
 817         if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
 818                 ret++;
 819         if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
 820                 ret++;
 821         if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
 822                 ret++;
 823         return ret;
 824 }
 825
 826 static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 827 {
 828         return list_empty(&sci->sc_dirty_files) &&
 829                 !test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
 830                 sci->sc_nfreesegs == 0 &&
 831                 (!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
 832 }
 833
 834 static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 835 {
 836         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 837         int ret = 0;
 838
 839         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
 840                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
 841
 842         spin_lock(&nilfs->ns_inode_lock);
 843         if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
 844                 ret++;
 845
 846         spin_unlock(&nilfs->ns_inode_lock);
 847         return ret;
 848 }
 849
 850 static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 851 {
 852         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 853
 854         nilfs_mdt_clear_dirty(sci->sc_root->ifile);
 855         nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
 856         nilfs_mdt_clear_dirty(nilfs->ns_sufile);
 857         nilfs_mdt_clear_dirty(nilfs->ns_dat);
 858 }
 859
 860 static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
 861 {
 862         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 863         struct buffer_head *bh_cp;
 864         struct nilfs_checkpoint *raw_cp;
 865         int err;
 866
 867         /* XXX: this interface will be changed */
 868         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 1,
 869                                           &raw_cp, &bh_cp);
 870         if (likely(!err)) {
 871                 /*
 872                  * The following code is duplicated with cpfile.  But, it is
 873                  * needed to collect the checkpoint even if it was not newly
 874                  * created.
 875                  */
 876                 mark_buffer_dirty(bh_cp);
 877                 nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
 878                 nilfs_cpfile_put_checkpoint(
 879                         nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 880         } else if (err == -EINVAL || err == -ENOENT) {
 881                 nilfs_error(sci->sc_super,
 882                             "checkpoint creation failed due to metadata corruption.");
 883                 err = -EIO;
 884         }
 885         return err;
 886 }
 887
 888 static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
 889 {
 890         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 891         struct buffer_head *bh_cp;
 892         struct nilfs_checkpoint *raw_cp;
 893         int err;
 894
 895         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
 896                                           &raw_cp, &bh_cp);
 897         if (unlikely(err)) {
 898                 if (err == -EINVAL || err == -ENOENT) {
 899                         nilfs_error(sci->sc_super,
 900                                     "checkpoint finalization failed due to metadata corruption.");
 901                         err = -EIO;
 902                 }
 903                 goto failed_ibh;
 904         }
 905         raw_cp->cp_snapshot_list.ssl_next = 0;
 906         raw_cp->cp_snapshot_list.ssl_prev = 0;
 907         raw_cp->cp_inodes_count =
 908                 cpu_to_le64(atomic64_read(&sci->sc_root->inodes_count));
 909         raw_cp->cp_blocks_count =
 910                 cpu_to_le64(atomic64_read(&sci->sc_root->blocks_count));
 911         raw_cp->cp_nblk_inc =
 912                 cpu_to_le64(sci->sc_nblk_inc + sci->sc_nblk_this_inc);
 913         raw_cp->cp_create = cpu_to_le64(sci->sc_seg_ctime);
 914         raw_cp->cp_cno = cpu_to_le64(nilfs->ns_cno);
 915
 916         if (test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 917                 nilfs_checkpoint_clear_minor(raw_cp);
 918         else
 919                 nilfs_checkpoint_set_minor(raw_cp);
 920
 921         nilfs_write_inode_common(sci->sc_root->ifile,
 922                                  &raw_cp->cp_ifile_inode, 1);
 923         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 924         return 0;
 925
 926  failed_ibh:
 927         return err;
 928 }
 929
 930 static void nilfs_fill_in_file_bmap(struct inode *ifile,
 931                                     struct nilfs_inode_info *ii)
 932
 933 {
 934         struct buffer_head *ibh;
 935         struct nilfs_inode *raw_inode;
 936
 937         if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
 938                 ibh = ii->i_bh;
 939                 BUG_ON(!ibh);
 940                 raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
 941                                                   ibh);
 942                 nilfs_bmap_write(ii->i_bmap, raw_inode);
 943                 nilfs_ifile_unmap_inode(ifile, ii->vfs_inode.i_ino, ibh);
 944         }
 945 }
 946
 947 static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
 948 {
 949         struct nilfs_inode_info *ii;
 950
 951         list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
 952                 nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
 953                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
 954         }
 955 }
 956
 957 static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 958                                              struct the_nilfs *nilfs)
 959 {
 960         struct buffer_head *bh_sr;
 961         struct nilfs_super_root *raw_sr;
 962         unsigned int isz, srsz;
 963
 964         bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
 965         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 966         isz = nilfs->ns_inode_size;
 967         srsz = NILFS_SR_BYTES(isz);
 968
 969         raw_sr->sr_bytes = cpu_to_le16(srsz);
 970         raw_sr->sr_nongc_ctime
 971                 = cpu_to_le64(nilfs_doing_gc() ?
 972                               nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
 973         raw_sr->sr_flags = 0;
 974
 975         nilfs_write_inode_common(nilfs->ns_dat, (void *)raw_sr +
 976                                  NILFS_SR_DAT_OFFSET(isz), 1);
 977         nilfs_write_inode_common(nilfs->ns_cpfile, (void *)raw_sr +
 978                                  NILFS_SR_CPFILE_OFFSET(isz), 1);
 979         nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
 980                                  NILFS_SR_SUFILE_OFFSET(isz), 1);
 981         memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
 982 }
 983
 984 static void nilfs_redirty_inodes(struct list_head *head)
 985 {
 986         struct nilfs_inode_info *ii;
 987
 988         list_for_each_entry(ii, head, i_dirty) {
 989                 if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
 990                         clear_bit(NILFS_I_COLLECTED, &ii->i_state);
 991         }
 992 }
 993
 994 static void nilfs_drop_collected_inodes(struct list_head *head)
 995 {
 996         struct nilfs_inode_info *ii;
 997
 998         list_for_each_entry(ii, head, i_dirty) {
 999                 if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
1000                         continue;
1001
1002                 clear_bit(NILFS_I_INODE_SYNC, &ii->i_state);
1003                 set_bit(NILFS_I_UPDATED, &ii->i_state);
1004         }
1005 }
1006
1007 static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
1008                                        struct inode *inode,
1009                                        struct list_head *listp,
1010                                        int (*collect)(struct nilfs_sc_info *,
1011                                                       struct buffer_head *,
1012                                                       struct inode *))
1013 {
1014         struct buffer_head *bh, *n;
1015         int err = 0;
1016
1017         if (collect) {
1018                 list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
1019                         list_del_init(&bh->b_assoc_buffers);
1020                         err = collect(sci, bh, inode);
1021                         brelse(bh);
1022                         if (unlikely(err))
1023                                 goto dispose_buffers;
1024                 }
1025                 return 0;
1026         }
1027
1028  dispose_buffers:
1029         while (!list_empty(listp)) {
1030                 bh = list_first_entry(listp, struct buffer_head,
1031                                       b_assoc_buffers);
1032                 list_del_init(&bh->b_assoc_buffers);
1033                 brelse(bh);
1034         }
1035         return err;
1036 }
1037
1038 static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
1039 {
1040         /* Remaining number of blocks within segment buffer */
1041         return sci->sc_segbuf_nblocks -
1042                 (sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
1043 }
1044
1045 static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
1046                                    struct inode *inode,
1047                                    const struct nilfs_sc_operations *sc_ops)
1048 {
1049         LIST_HEAD(data_buffers);
1050         LIST_HEAD(node_buffers);
1051         int err;
1052
1053         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1054                 size_t n, rest = nilfs_segctor_buffer_rest(sci);
1055
1056                 n = nilfs_lookup_dirty_data_buffers(
1057                         inode, &data_buffers, rest + 1, 0, LLONG_MAX);
1058                 if (n > rest) {
1059                         err = nilfs_segctor_apply_buffers(
1060                                 sci, inode, &data_buffers,
1061                                 sc_ops->collect_data);
1062                         BUG_ON(!err); /* always receive -E2BIG or true error */
1063                         goto break_or_fail;
1064                 }
1065         }
1066         nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
1067
1068         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1069                 err = nilfs_segctor_apply_buffers(
1070                         sci, inode, &data_buffers, sc_ops->collect_data);
1071                 if (unlikely(err)) {
1072                         /* dispose node list */
1073                         nilfs_segctor_apply_buffers(
1074                                 sci, inode, &node_buffers, NULL);
1075                         goto break_or_fail;
1076                 }
1077                 sci->sc_stage.flags |= NILFS_CF_NODE;
1078         }
1079         /* Collect node */
1080         err = nilfs_segctor_apply_buffers(
1081                 sci, inode, &node_buffers, sc_ops->collect_node);
1082         if (unlikely(err))
1083                 goto break_or_fail;
1084
1085         nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1086         err = nilfs_segctor_apply_buffers(
1087                 sci, inode, &node_buffers, sc_ops->collect_bmap);
1088         if (unlikely(err))
1089                 goto break_or_fail;
1090
1091         nilfs_segctor_end_finfo(sci, inode);
1092         sci->sc_stage.flags &= ~NILFS_CF_NODE;
1093
1094  break_or_fail:
1095         return err;
1096 }
1097
1098 static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1099                                          struct inode *inode)
1100 {
1101         LIST_HEAD(data_buffers);
1102         size_t n, rest = nilfs_segctor_buffer_rest(sci);
1103         int err;
1104
1105         n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1106                                             sci->sc_dsync_start,
1107                                             sci->sc_dsync_end);
1108
1109         err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1110                                           nilfs_collect_file_data);
1111         if (!err) {
1112                 nilfs_segctor_end_finfo(sci, inode);
1113                 BUG_ON(n > rest);
1114                 /* always receive -E2BIG or true error if n > rest */
1115         }
1116         return err;
1117 }
1118
1119 static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1120 {
1121         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1122         struct list_head *head;
1123         struct nilfs_inode_info *ii;
1124         size_t ndone;
1125         int err = 0;
1126
1127         switch (nilfs_sc_cstage_get(sci)) {
1128         case NILFS_ST_INIT:
1129                 /* Pre-processes */
1130                 sci->sc_stage.flags = 0;
1131
1132                 if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1133                         sci->sc_nblk_inc = 0;
1134                         sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1135                         if (mode == SC_LSEG_DSYNC) {
1136                                 nilfs_sc_cstage_set(sci, NILFS_ST_DSYNC);
1137                                 goto dsync_mode;
1138                         }
1139                 }
1140
1141                 sci->sc_stage.dirty_file_ptr = NULL;
1142                 sci->sc_stage.gc_inode_ptr = NULL;
1143                 if (mode == SC_FLUSH_DAT) {
1144                         nilfs_sc_cstage_set(sci, NILFS_ST_DAT);
1145                         goto dat_stage;
1146                 }
1147                 nilfs_sc_cstage_inc(sci);
1148                 fallthrough;
1149         case NILFS_ST_GC:
1150                 if (nilfs_doing_gc()) {
1151                         head = &sci->sc_gc_inodes;
1152                         ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1153                                                 head, i_dirty);
1154                         list_for_each_entry_continue(ii, head, i_dirty) {
1155                                 err = nilfs_segctor_scan_file(
1156                                         sci, &ii->vfs_inode,
1157                                         &nilfs_sc_file_ops);
1158                                 if (unlikely(err)) {
1159                                         sci->sc_stage.gc_inode_ptr = list_entry(
1160                                                 ii->i_dirty.prev,
1161                                                 struct nilfs_inode_info,
1162                                                 i_dirty);
1163                                         goto break_or_fail;
1164                                 }
1165                                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
1166                         }
1167                         sci->sc_stage.gc_inode_ptr = NULL;
1168                 }
1169                 nilfs_sc_cstage_inc(sci);
1170                 fallthrough;
1171         case NILFS_ST_FILE:
1172                 head = &sci->sc_dirty_files;
1173                 ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1174                                         i_dirty);
1175                 list_for_each_entry_continue(ii, head, i_dirty) {
1176                         clear_bit(NILFS_I_DIRTY, &ii->i_state);
1177
1178                         err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1179                                                       &nilfs_sc_file_ops);
1180                         if (unlikely(err)) {
1181                                 sci->sc_stage.dirty_file_ptr =
1182                                         list_entry(ii->i_dirty.prev,
1183                                                    struct nilfs_inode_info,
1184                                                    i_dirty);
1185                                 goto break_or_fail;
1186                         }
1187                         /* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1188                         /* XXX: required ? */
1189                 }
1190                 sci->sc_stage.dirty_file_ptr = NULL;
1191                 if (mode == SC_FLUSH_FILE) {
1192                         nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1193                         return 0;
1194                 }
1195                 nilfs_sc_cstage_inc(sci);
1196                 sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1197                 fallthrough;
1198         case NILFS_ST_IFILE:
1199                 err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1200                                               &nilfs_sc_file_ops);
1201                 if (unlikely(err))
1202                         break;
1203                 nilfs_sc_cstage_inc(sci);
1204                 /* Creating a checkpoint */
1205                 err = nilfs_segctor_create_checkpoint(sci);
1206                 if (unlikely(err))
1207                         break;
1208                 fallthrough;
1209         case NILFS_ST_CPFILE:
1210                 err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1211                                               &nilfs_sc_file_ops);
1212                 if (unlikely(err))
1213                         break;
1214                 nilfs_sc_cstage_inc(sci);
1215                 fallthrough;
1216         case NILFS_ST_SUFILE:
1217                 err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1218                                          sci->sc_nfreesegs, &ndone);
1219                 if (unlikely(err)) {
1220                         nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1221                                                   sci->sc_freesegs, ndone,
1222                                                   NULL);
1223                         break;
1224                 }
1225                 sci->sc_stage.flags |= NILFS_CF_SUFREED;
1226
1227                 err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1228                                               &nilfs_sc_file_ops);
1229                 if (unlikely(err))
1230                         break;
1231                 nilfs_sc_cstage_inc(sci);
1232                 fallthrough;
1233         case NILFS_ST_DAT:
1234  dat_stage:
1235                 err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1236                                               &nilfs_sc_dat_ops);
1237                 if (unlikely(err))
1238                         break;
1239                 if (mode == SC_FLUSH_DAT) {
1240                         nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1241                         return 0;
1242                 }
1243                 nilfs_sc_cstage_inc(sci);
1244                 fallthrough;
1245         case NILFS_ST_SR:
1246                 if (mode == SC_LSEG_SR) {
1247                         /* Appending a super root */
1248                         err = nilfs_segctor_add_super_root(sci);
1249                         if (unlikely(err))
1250                                 break;
1251                 }
1252                 /* End of a logical segment */
1253                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1254                 nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1255                 return 0;
1256         case NILFS_ST_DSYNC:
1257  dsync_mode:
1258                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1259                 ii = sci->sc_dsync_inode;
1260                 if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1261                         break;
1262
1263                 err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1264                 if (unlikely(err))
1265                         break;
1266                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1267                 nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1268                 return 0;
1269         case NILFS_ST_DONE:
1270                 return 0;
1271         default:
1272                 BUG();
1273         }
1274
1275  break_or_fail:
1276         return err;
1277 }
1278
1279 /**
1280  * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1281  * @sci: nilfs_sc_info
1282  * @nilfs: nilfs object
1283  */
1284 static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1285                                             struct the_nilfs *nilfs)
1286 {
1287         struct nilfs_segment_buffer *segbuf, *prev;
1288         __u64 nextnum;
1289         int err, alloc = 0;
1290
1291         segbuf = nilfs_segbuf_new(sci->sc_super);
1292         if (unlikely(!segbuf))
1293                 return -ENOMEM;
1294
1295         if (list_empty(&sci->sc_write_logs)) {
1296                 nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1297                                  nilfs->ns_pseg_offset, nilfs);
1298                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1299                         nilfs_shift_to_next_segment(nilfs);
1300                         nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1301                 }
1302
1303                 segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1304                 nextnum = nilfs->ns_nextnum;
1305
1306                 if (nilfs->ns_segnum == nilfs->ns_nextnum)
1307                         /* Start from the head of a new full segment */
1308                         alloc++;
1309         } else {
1310                 /* Continue logs */
1311                 prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1312                 nilfs_segbuf_map_cont(segbuf, prev);
1313                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1314                 nextnum = prev->sb_nextnum;
1315
1316                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1317                         nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1318                         segbuf->sb_sum.seg_seq++;
1319                         alloc++;
1320                 }
1321         }
1322
1323         err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1324         if (err)
1325                 goto failed;
1326
1327         if (alloc) {
1328                 err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1329                 if (err)
1330                         goto failed;
1331         }
1332         nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1333
1334         BUG_ON(!list_empty(&sci->sc_segbufs));
1335         list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1336         sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1337         return 0;
1338
1339  failed:
1340         nilfs_segbuf_free(segbuf);
1341         return err;
1342 }
1343
1344 static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1345                                          struct the_nilfs *nilfs, int nadd)
1346 {
1347         struct nilfs_segment_buffer *segbuf, *prev;
1348         struct inode *sufile = nilfs->ns_sufile;
1349         __u64 nextnextnum;
1350         LIST_HEAD(list);
1351         int err, ret, i;
1352
1353         prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1354         /*
1355          * Since the segment specified with nextnum might be allocated during
1356          * the previous construction, the buffer including its segusage may
1357          * not be dirty.  The following call ensures that the buffer is dirty
1358          * and will pin the buffer on memory until the sufile is written.
1359          */
1360         err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1361         if (unlikely(err))
1362                 return err;
1363
1364         for (i = 0; i < nadd; i++) {
1365                 /* extend segment info */
1366                 err = -ENOMEM;
1367                 segbuf = nilfs_segbuf_new(sci->sc_super);
1368                 if (unlikely(!segbuf))
1369                         goto failed;
1370
1371                 /* map this buffer to region of segment on-disk */
1372                 nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1373                 sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1374
1375                 /* allocate the next next full segment */
1376                 err = nilfs_sufile_alloc(sufile, &nextnextnum);
1377                 if (unlikely(err))
1378                         goto failed_segbuf;
1379
1380                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1381                 nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1382
1383                 list_add_tail(&segbuf->sb_list, &list);
1384                 prev = segbuf;
1385         }
1386         list_splice_tail(&list, &sci->sc_segbufs);
1387         return 0;
1388
1389  failed_segbuf:
1390         nilfs_segbuf_free(segbuf);
1391  failed:
1392         list_for_each_entry(segbuf, &list, sb_list) {
1393                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1394                 WARN_ON(ret); /* never fails */
1395         }
1396         nilfs_destroy_logs(&list);
1397         return err;
1398 }
1399
1400 static void nilfs_free_incomplete_logs(struct list_head *logs,
1401                                        struct the_nilfs *nilfs)
1402 {
1403         struct nilfs_segment_buffer *segbuf, *prev;
1404         struct inode *sufile = nilfs->ns_sufile;
1405         int ret;
1406
1407         segbuf = NILFS_FIRST_SEGBUF(logs);
1408         if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1409                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1410                 WARN_ON(ret); /* never fails */
1411         }
1412         if (atomic_read(&segbuf->sb_err)) {
1413                 /* Case 1: The first segment failed */
1414                 if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1415                         /*
1416                          * Case 1a:  Partial segment appended into an existing
1417                          * segment
1418                          */
1419                         nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1420                                                 segbuf->sb_fseg_end);
1421                 else /* Case 1b:  New full segment */
1422                         set_nilfs_discontinued(nilfs);
1423         }
1424
1425         prev = segbuf;
1426         list_for_each_entry_continue(segbuf, logs, sb_list) {
1427                 if (prev->sb_nextnum != segbuf->sb_nextnum) {
1428                         ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1429                         WARN_ON(ret); /* never fails */
1430                 }
1431                 if (atomic_read(&segbuf->sb_err) &&
1432                     segbuf->sb_segnum != nilfs->ns_nextnum)
1433                         /* Case 2: extended segment (!= next) failed */
1434                         nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1435                 prev = segbuf;
1436         }
1437 }
1438
1439 static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1440                                           struct inode *sufile)
1441 {
1442         struct nilfs_segment_buffer *segbuf;
1443         unsigned long live_blocks;
1444         int ret;
1445
1446         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1447                 live_blocks = segbuf->sb_sum.nblocks +
1448                         (segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1449                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1450                                                      live_blocks,
1451                                                      sci->sc_seg_ctime);
1452                 WARN_ON(ret); /* always succeed because the segusage is dirty */
1453         }
1454 }
1455
1456 static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1457 {
1458         struct nilfs_segment_buffer *segbuf;
1459         int ret;
1460
1461         segbuf = NILFS_FIRST_SEGBUF(logs);
1462         ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1463                                              segbuf->sb_pseg_start -
1464                                              segbuf->sb_fseg_start, 0);
1465         WARN_ON(ret); /* always succeed because the segusage is dirty */
1466
1467         list_for_each_entry_continue(segbuf, logs, sb_list) {
1468                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1469                                                      0, 0);
1470                 WARN_ON(ret); /* always succeed */
1471         }
1472 }
1473
1474 static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1475                                             struct nilfs_segment_buffer *last,
1476                                             struct inode *sufile)
1477 {
1478         struct nilfs_segment_buffer *segbuf = last;
1479         int ret;
1480
1481         list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1482                 sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1483                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1484                 WARN_ON(ret);
1485         }
1486         nilfs_truncate_logs(&sci->sc_segbufs, last);
1487 }
1488
1489
1490 static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1491                                  struct the_nilfs *nilfs, int mode)
1492 {
1493         struct nilfs_cstage prev_stage = sci->sc_stage;
1494         int err, nadd = 1;
1495
1496         /* Collection retry loop */
1497         for (;;) {
1498                 sci->sc_nblk_this_inc = 0;
1499                 sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1500
1501                 err = nilfs_segctor_reset_segment_buffer(sci);
1502                 if (unlikely(err))
1503                         goto failed;
1504
1505                 err = nilfs_segctor_collect_blocks(sci, mode);
1506                 sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1507                 if (!err)
1508                         break;
1509
1510                 if (unlikely(err != -E2BIG))
1511                         goto failed;
1512
1513                 /* The current segment is filled up */
1514                 if (mode != SC_LSEG_SR ||
1515                     nilfs_sc_cstage_get(sci) < NILFS_ST_CPFILE)
1516                         break;
1517
1518                 nilfs_clear_logs(&sci->sc_segbufs);
1519
1520                 if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1521                         err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1522                                                         sci->sc_freesegs,
1523                                                         sci->sc_nfreesegs,
1524                                                         NULL);
1525                         WARN_ON(err); /* do not happen */
1526                         sci->sc_stage.flags &= ~NILFS_CF_SUFREED;
1527                 }
1528
1529                 err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1530                 if (unlikely(err))
1531                         return err;
1532
1533                 nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1534                 sci->sc_stage = prev_stage;
1535         }
1536         nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1537         return 0;
1538
1539  failed:
1540         return err;
1541 }
1542
1543 static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1544                                       struct buffer_head *new_bh)
1545 {
1546         BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1547
1548         list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1549         /* The caller must release old_bh */
1550 }
1551
1552 static int
1553 nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1554                                      struct nilfs_segment_buffer *segbuf,
1555                                      int mode)
1556 {
1557         struct inode *inode = NULL;
1558         sector_t blocknr;
1559         unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1560         unsigned long nblocks = 0, ndatablk = 0;
1561         const struct nilfs_sc_operations *sc_op = NULL;
1562         struct nilfs_segsum_pointer ssp;
1563         struct nilfs_finfo *finfo = NULL;
1564         union nilfs_binfo binfo;
1565         struct buffer_head *bh, *bh_org;
1566         ino_t ino = 0;
1567         int err = 0;
1568
1569         if (!nfinfo)
1570                 goto out;
1571
1572         blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1573         ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1574         ssp.offset = sizeof(struct nilfs_segment_summary);
1575
1576         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1577                 if (bh == segbuf->sb_super_root)
1578                         break;
1579                 if (!finfo) {
1580                         finfo = nilfs_segctor_map_segsum_entry(
1581                                 sci, &ssp, sizeof(*finfo));
1582                         ino = le64_to_cpu(finfo->fi_ino);
1583                         nblocks = le32_to_cpu(finfo->fi_nblocks);
1584                         ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1585
1586                         inode = bh->b_folio->mapping->host;
1587
1588                         if (mode == SC_LSEG_DSYNC)
1589                                 sc_op = &nilfs_sc_dsync_ops;
1590                         else if (ino == NILFS_DAT_INO)
1591                                 sc_op = &nilfs_sc_dat_ops;
1592                         else /* file blocks */
1593                                 sc_op = &nilfs_sc_file_ops;
1594                 }
1595                 bh_org = bh;
1596                 get_bh(bh_org);
1597                 err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1598                                         &binfo);
1599                 if (bh != bh_org)
1600                         nilfs_list_replace_buffer(bh_org, bh);
1601                 brelse(bh_org);
1602                 if (unlikely(err))
1603                         goto failed_bmap;
1604
1605                 if (ndatablk > 0)
1606                         sc_op->write_data_binfo(sci, &ssp, &binfo);
1607                 else
1608                         sc_op->write_node_binfo(sci, &ssp, &binfo);
1609
1610                 blocknr++;
1611                 if (--nblocks == 0) {
1612                         finfo = NULL;
1613                         if (--nfinfo == 0)
1614                                 break;
1615                 } else if (ndatablk > 0)
1616                         ndatablk--;
1617         }
1618  out:
1619         return 0;
1620
1621  failed_bmap:
1622         return err;
1623 }
1624
1625 static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1626 {
1627         struct nilfs_segment_buffer *segbuf;
1628         int err;
1629
1630         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1631                 err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1632                 if (unlikely(err))
1633                         return err;
1634                 nilfs_segbuf_fill_in_segsum(segbuf);
1635         }
1636         return 0;
1637 }
1638
1639 static void nilfs_begin_page_io(struct page *page)
1640 {
1641         if (!page || PageWriteback(page))
1642                 /*
1643                  * For split b-tree node pages, this function may be called
1644                  * twice.  We ignore the 2nd or later calls by this check.
1645                  */
1646                 return;
1647
1648         lock_page(page);
1649         clear_page_dirty_for_io(page);
1650         set_page_writeback(page);
1651         unlock_page(page);
1652 }
1653
1654 static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci)
1655 {
1656         struct nilfs_segment_buffer *segbuf;
1657         struct page *bd_page = NULL, *fs_page = NULL;
1658
1659         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1660                 struct buffer_head *bh;
1661
1662                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1663                                     b_assoc_buffers) {
1664                         if (bh->b_page != bd_page) {
1665                                 if (bd_page) {
1666                                         lock_page(bd_page);
1667                                         clear_page_dirty_for_io(bd_page);
1668                                         set_page_writeback(bd_page);
1669                                         unlock_page(bd_page);
1670                                 }
1671                                 bd_page = bh->b_page;
1672                         }
1673                 }
1674
1675                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1676                                     b_assoc_buffers) {
1677                         set_buffer_async_write(bh);
1678                         if (bh == segbuf->sb_super_root) {
1679                                 if (bh->b_page != bd_page) {
1680                                         lock_page(bd_page);
1681                                         clear_page_dirty_for_io(bd_page);
1682                                         set_page_writeback(bd_page);
1683                                         unlock_page(bd_page);
1684                                         bd_page = bh->b_page;
1685                                 }
1686                                 break;
1687                         }
1688                         if (bh->b_page != fs_page) {
1689                                 nilfs_begin_page_io(fs_page);
1690                                 fs_page = bh->b_page;
1691                         }
1692                 }
1693         }
1694         if (bd_page) {
1695                 lock_page(bd_page);
1696                 clear_page_dirty_for_io(bd_page);
1697                 set_page_writeback(bd_page);
1698                 unlock_page(bd_page);
1699         }
1700         nilfs_begin_page_io(fs_page);
1701 }
1702
1703 static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1704                                struct the_nilfs *nilfs)
1705 {
1706         int ret;
1707
1708         ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1709         list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1710         return ret;
1711 }
1712
1713 static void nilfs_end_page_io(struct page *page, int err)
1714 {
1715         if (!page)
1716                 return;
1717
1718         if (buffer_nilfs_node(page_buffers(page)) && !PageWriteback(page)) {
1719                 /*
1720                  * For b-tree node pages, this function may be called twice
1721                  * or more because they might be split in a segment.
1722                  */
1723                 if (PageDirty(page)) {
1724                         /*
1725                          * For pages holding split b-tree node buffers, dirty
1726                          * flag on the buffers may be cleared discretely.
1727                          * In that case, the page is once redirtied for
1728                          * remaining buffers, and it must be cancelled if
1729                          * all the buffers get cleaned later.
1730                          */
1731                         lock_page(page);
1732                         if (nilfs_page_buffers_clean(page))
1733                                 __nilfs_clear_page_dirty(page);
1734                         unlock_page(page);
1735                 }
1736                 return;
1737         }
1738
1739         if (!err) {
1740                 if (!nilfs_page_buffers_clean(page))
1741                         __set_page_dirty_nobuffers(page);
1742                 ClearPageError(page);
1743         } else {
1744                 __set_page_dirty_nobuffers(page);
1745                 SetPageError(page);
1746         }
1747
1748         end_page_writeback(page);
1749 }
1750
1751 static void nilfs_abort_logs(struct list_head *logs, int err)
1752 {
1753         struct nilfs_segment_buffer *segbuf;
1754         struct page *bd_page = NULL, *fs_page = NULL;
1755         struct buffer_head *bh;
1756
1757         if (list_empty(logs))
1758                 return;
1759
1760         list_for_each_entry(segbuf, logs, sb_list) {
1761                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1762                                     b_assoc_buffers) {
1763                         if (bh->b_page != bd_page) {
1764                                 if (bd_page)
1765                                         end_page_writeback(bd_page);
1766                                 bd_page = bh->b_page;
1767                         }
1768                 }
1769
1770                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1771                                     b_assoc_buffers) {
1772                         clear_buffer_async_write(bh);
1773                         if (bh == segbuf->sb_super_root) {
1774                                 if (bh->b_page != bd_page) {
1775                                         end_page_writeback(bd_page);
1776                                         bd_page = bh->b_page;
1777                                 }
1778                                 break;
1779                         }
1780                         if (bh->b_page != fs_page) {
1781                                 nilfs_end_page_io(fs_page, err);
1782                                 fs_page = bh->b_page;
1783                         }
1784                 }
1785         }
1786         if (bd_page)
1787                 end_page_writeback(bd_page);
1788
1789         nilfs_end_page_io(fs_page, err);
1790 }
1791
1792 static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
1793                                              struct the_nilfs *nilfs, int err)
1794 {
1795         LIST_HEAD(logs);
1796         int ret;
1797
1798         list_splice_tail_init(&sci->sc_write_logs, &logs);
1799         ret = nilfs_wait_on_logs(&logs);
1800         nilfs_abort_logs(&logs, ret ? : err);
1801
1802         list_splice_tail_init(&sci->sc_segbufs, &logs);
1803         nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
1804         nilfs_free_incomplete_logs(&logs, nilfs);
1805
1806         if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1807                 ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1808                                                 sci->sc_freesegs,
1809                                                 sci->sc_nfreesegs,
1810                                                 NULL);
1811                 WARN_ON(ret); /* do not happen */
1812         }
1813
1814         nilfs_destroy_logs(&logs);
1815 }
1816
1817 static void nilfs_set_next_segment(struct the_nilfs *nilfs,
1818                                    struct nilfs_segment_buffer *segbuf)
1819 {
1820         nilfs->ns_segnum = segbuf->sb_segnum;
1821         nilfs->ns_nextnum = segbuf->sb_nextnum;
1822         nilfs->ns_pseg_offset = segbuf->sb_pseg_start - segbuf->sb_fseg_start
1823                 + segbuf->sb_sum.nblocks;
1824         nilfs->ns_seg_seq = segbuf->sb_sum.seg_seq;
1825         nilfs->ns_ctime = segbuf->sb_sum.ctime;
1826 }
1827
1828 static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
1829 {
1830         struct nilfs_segment_buffer *segbuf;
1831         struct page *bd_page = NULL, *fs_page = NULL;
1832         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1833         int update_sr = false;
1834
1835         list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
1836                 struct buffer_head *bh;
1837
1838                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1839                                     b_assoc_buffers) {
1840                         set_buffer_uptodate(bh);
1841                         clear_buffer_dirty(bh);
1842                         if (bh->b_page != bd_page) {
1843                                 if (bd_page)
1844                                         end_page_writeback(bd_page);
1845                                 bd_page = bh->b_page;
1846                         }
1847                 }
1848                 /*
1849                  * We assume that the buffers which belong to the same page
1850                  * continue over the buffer list.
1851                  * Under this assumption, the last BHs of pages is
1852                  * identifiable by the discontinuity of bh->b_page
1853                  * (page != fs_page).
1854                  *
1855                  * For B-tree node blocks, however, this assumption is not
1856                  * guaranteed.  The cleanup code of B-tree node pages needs
1857                  * special care.
1858                  */
1859                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1860                                     b_assoc_buffers) {
1861                         const unsigned long set_bits = BIT(BH_Uptodate);
1862                         const unsigned long clear_bits =
1863                                 (BIT(BH_Dirty) | BIT(BH_Async_Write) |
1864                                  BIT(BH_Delay) | BIT(BH_NILFS_Volatile) |
1865                                  BIT(BH_NILFS_Redirected));
1866
1867                         set_mask_bits(&bh->b_state, clear_bits, set_bits);
1868                         if (bh == segbuf->sb_super_root) {
1869                                 if (bh->b_page != bd_page) {
1870                                         end_page_writeback(bd_page);
1871                                         bd_page = bh->b_page;
1872                                 }
1873                                 update_sr = true;
1874                                 break;
1875                         }
1876                         if (bh->b_page != fs_page) {
1877                                 nilfs_end_page_io(fs_page, 0);
1878                                 fs_page = bh->b_page;
1879                         }
1880                 }
1881
1882                 if (!nilfs_segbuf_simplex(segbuf)) {
1883                         if (segbuf->sb_sum.flags & NILFS_SS_LOGBGN) {
1884                                 set_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1885                                 sci->sc_lseg_stime = jiffies;
1886                         }
1887                         if (segbuf->sb_sum.flags & NILFS_SS_LOGEND)
1888                                 clear_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1889                 }
1890         }
1891         /*
1892          * Since pages may continue over multiple segment buffers,
1893          * end of the last page must be checked outside of the loop.
1894          */
1895         if (bd_page)
1896                 end_page_writeback(bd_page);
1897
1898         nilfs_end_page_io(fs_page, 0);
1899
1900         nilfs_drop_collected_inodes(&sci->sc_dirty_files);
1901
1902         if (nilfs_doing_gc())
1903                 nilfs_drop_collected_inodes(&sci->sc_gc_inodes);
1904         else
1905                 nilfs->ns_nongc_ctime = sci->sc_seg_ctime;
1906
1907         sci->sc_nblk_inc += sci->sc_nblk_this_inc;
1908
1909         segbuf = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1910         nilfs_set_next_segment(nilfs, segbuf);
1911
1912         if (update_sr) {
1913                 nilfs->ns_flushed_device = 0;
1914                 nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
1915                                        segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
1916
1917                 clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
1918                 clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1919                 set_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1920                 nilfs_segctor_clear_metadata_dirty(sci);
1921         } else
1922                 clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1923 }
1924
1925 static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
1926 {
1927         int ret;
1928
1929         ret = nilfs_wait_on_logs(&sci->sc_write_logs);
1930         if (!ret) {
1931                 nilfs_segctor_complete_write(sci);
1932                 nilfs_destroy_logs(&sci->sc_write_logs);
1933         }
1934         return ret;
1935 }
1936
1937 static int nilfs_segctor_collect_dirty_files(struct nilfs_sc_info *sci,
1938                                              struct the_nilfs *nilfs)
1939 {
1940         struct nilfs_inode_info *ii, *n;
1941         struct inode *ifile = sci->sc_root->ifile;
1942
1943         spin_lock(&nilfs->ns_inode_lock);
1944  retry:
1945         list_for_each_entry_safe(ii, n, &nilfs->ns_dirty_files, i_dirty) {
1946                 if (!ii->i_bh) {
1947                         struct buffer_head *ibh;
1948                         int err;
1949
1950                         spin_unlock(&nilfs->ns_inode_lock);
1951                         err = nilfs_ifile_get_inode_block(
1952                                 ifile, ii->vfs_inode.i_ino, &ibh);
1953                         if (unlikely(err)) {
1954                                 nilfs_warn(sci->sc_super,
1955                                            "log writer: error %d getting inode block (ino=%lu)",
1956                                            err, ii->vfs_inode.i_ino);
1957                                 return err;
1958                         }
1959                         spin_lock(&nilfs->ns_inode_lock);
1960                         if (likely(!ii->i_bh))
1961                                 ii->i_bh = ibh;
1962                         else
1963                                 brelse(ibh);
1964                         goto retry;
1965                 }
1966
1967                 // Always redirty the buffer to avoid race condition
1968                 mark_buffer_dirty(ii->i_bh);
1969                 nilfs_mdt_mark_dirty(ifile);
1970
1971                 clear_bit(NILFS_I_QUEUED, &ii->i_state);
1972                 set_bit(NILFS_I_BUSY, &ii->i_state);
1973                 list_move_tail(&ii->i_dirty, &sci->sc_dirty_files);
1974         }
1975         spin_unlock(&nilfs->ns_inode_lock);
1976
1977         return 0;
1978 }
1979
1980 static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
1981                                              struct the_nilfs *nilfs)
1982 {
1983         struct nilfs_inode_info *ii, *n;
1984         int during_mount = !(sci->sc_super->s_flags & SB_ACTIVE);
1985         int defer_iput = false;
1986
1987         spin_lock(&nilfs->ns_inode_lock);
1988         list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
1989                 if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
1990                     test_bit(NILFS_I_DIRTY, &ii->i_state))
1991                         continue;
1992
1993                 clear_bit(NILFS_I_BUSY, &ii->i_state);
1994                 brelse(ii->i_bh);
1995                 ii->i_bh = NULL;
1996                 list_del_init(&ii->i_dirty);
1997                 if (!ii->vfs_inode.i_nlink || during_mount) {
1998                         /*
1999                          * Defer calling iput() to avoid deadlocks if
2000                          * i_nlink == 0 or mount is not yet finished.
2001                          */
2002                         list_add_tail(&ii->i_dirty, &sci->sc_iput_queue);
2003                         defer_iput = true;
2004                 } else {
2005                         spin_unlock(&nilfs->ns_inode_lock);
2006                         iput(&ii->vfs_inode);
2007                         spin_lock(&nilfs->ns_inode_lock);
2008                 }
2009         }
2010         spin_unlock(&nilfs->ns_inode_lock);
2011
2012         if (defer_iput)
2013                 schedule_work(&sci->sc_iput_work);
2014 }
2015
2016 /*
2017  * Main procedure of segment constructor
2018  */
2019 static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
2020 {
2021         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2022         int err;
2023
2024         nilfs_sc_cstage_set(sci, NILFS_ST_INIT);
2025         sci->sc_cno = nilfs->ns_cno;
2026
2027         err = nilfs_segctor_collect_dirty_files(sci, nilfs);
2028         if (unlikely(err))
2029                 goto out;
2030
2031         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
2032                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
2033
2034         if (nilfs_segctor_clean(sci))
2035                 goto out;
2036
2037         do {
2038                 sci->sc_stage.flags &= ~NILFS_CF_HISTORY_MASK;
2039
2040                 err = nilfs_segctor_begin_construction(sci, nilfs);
2041                 if (unlikely(err))
2042                         goto out;
2043
2044                 /* Update time stamp */
2045                 sci->sc_seg_ctime = ktime_get_real_seconds();
2046
2047                 err = nilfs_segctor_collect(sci, nilfs, mode);
2048                 if (unlikely(err))
2049                         goto failed;
2050
2051                 /* Avoid empty segment */
2052                 if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE &&
2053                     nilfs_segbuf_empty(sci->sc_curseg)) {
2054                         nilfs_segctor_abort_construction(sci, nilfs, 1);
2055                         goto out;
2056                 }
2057
2058                 err = nilfs_segctor_assign(sci, mode);
2059                 if (unlikely(err))
2060                         goto failed;
2061
2062                 if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2063                         nilfs_segctor_fill_in_file_bmap(sci);
2064
2065                 if (mode == SC_LSEG_SR &&
2066                     nilfs_sc_cstage_get(sci) >= NILFS_ST_CPFILE) {
2067                         err = nilfs_segctor_fill_in_checkpoint(sci);
2068                         if (unlikely(err))
2069                                 goto failed_to_write;
2070
2071                         nilfs_segctor_fill_in_super_root(sci, nilfs);
2072                 }
2073                 nilfs_segctor_update_segusage(sci, nilfs->ns_sufile);
2074
2075                 /* Write partial segments */
2076                 nilfs_segctor_prepare_write(sci);
2077
2078                 nilfs_add_checksums_on_logs(&sci->sc_segbufs,
2079                                             nilfs->ns_crc_seed);
2080
2081                 err = nilfs_segctor_write(sci, nilfs);
2082                 if (unlikely(err))
2083                         goto failed_to_write;
2084
2085                 if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE ||
2086                     nilfs->ns_blocksize_bits != PAGE_SHIFT) {
2087                         /*
2088                          * At this point, we avoid double buffering
2089                          * for blocksize < pagesize because page dirty
2090                          * flag is turned off during write and dirty
2091                          * buffers are not properly collected for
2092                          * pages crossing over segments.
2093                          */
2094                         err = nilfs_segctor_wait(sci);
2095                         if (err)
2096                                 goto failed_to_write;
2097                 }
2098         } while (nilfs_sc_cstage_get(sci) != NILFS_ST_DONE);
2099
2100  out:
2101         nilfs_segctor_drop_written_files(sci, nilfs);
2102         return err;
2103
2104  failed_to_write:
2105         if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2106                 nilfs_redirty_inodes(&sci->sc_dirty_files);
2107
2108  failed:
2109         if (nilfs_doing_gc())
2110                 nilfs_redirty_inodes(&sci->sc_gc_inodes);
2111         nilfs_segctor_abort_construction(sci, nilfs, err);
2112         goto out;
2113 }
2114
2115 /**
2116  * nilfs_segctor_start_timer - set timer of background write
2117  * @sci: nilfs_sc_info
2118  *
2119  * If the timer has already been set, it ignores the new request.
2120  * This function MUST be called within a section locking the segment
2121  * semaphore.
2122  */
2123 static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
2124 {
2125         spin_lock(&sci->sc_state_lock);
2126         if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
2127                 sci->sc_timer.expires = jiffies + sci->sc_interval;
2128                 add_timer(&sci->sc_timer);
2129                 sci->sc_state |= NILFS_SEGCTOR_COMMIT;
2130         }
2131         spin_unlock(&sci->sc_state_lock);
2132 }
2133
2134 static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
2135 {
2136         spin_lock(&sci->sc_state_lock);
2137         if (!(sci->sc_flush_request & BIT(bn))) {
2138                 unsigned long prev_req = sci->sc_flush_request;
2139
2140                 sci->sc_flush_request |= BIT(bn);
2141                 if (!prev_req)
2142                         wake_up(&sci->sc_wait_daemon);
2143         }
2144         spin_unlock(&sci->sc_state_lock);
2145 }
2146
2147 /**
2148  * nilfs_flush_segment - trigger a segment construction for resource control
2149  * @sb: super block
2150  * @ino: inode number of the file to be flushed out.
2151  */
2152 void nilfs_flush_segment(struct super_block *sb, ino_t ino)
2153 {
2154         struct the_nilfs *nilfs = sb->s_fs_info;
2155         struct nilfs_sc_info *sci = nilfs->ns_writer;
2156
2157         if (!sci || nilfs_doing_construction())
2158                 return;
2159         nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
2160                                         /* assign bit 0 to data files */
2161 }
2162
2163 struct nilfs_segctor_wait_request {
2164         wait_queue_entry_t      wq;
2165         __u32           seq;
2166         int             err;
2167         atomic_t        done;
2168 };
2169
2170 static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
2171 {
2172         struct nilfs_segctor_wait_request wait_req;
2173         int err = 0;
2174
2175         spin_lock(&sci->sc_state_lock);
2176         init_wait(&wait_req.wq);
2177         wait_req.err = 0;
2178         atomic_set(&wait_req.done, 0);
2179         wait_req.seq = ++sci->sc_seq_request;
2180         spin_unlock(&sci->sc_state_lock);
2181
2182         init_waitqueue_entry(&wait_req.wq, current);
2183         add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
2184         set_current_state(TASK_INTERRUPTIBLE);
2185         wake_up(&sci->sc_wait_daemon);
2186
2187         for (;;) {
2188                 if (atomic_read(&wait_req.done)) {
2189                         err = wait_req.err;
2190                         break;
2191                 }
2192                 if (!signal_pending(current)) {
2193                         schedule();
2194                         continue;
2195                 }
2196                 err = -ERESTARTSYS;
2197                 break;
2198         }
2199         finish_wait(&sci->sc_wait_request, &wait_req.wq);
2200         return err;
2201 }
2202
2203 static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
2204 {
2205         struct nilfs_segctor_wait_request *wrq, *n;
2206         unsigned long flags;
2207
2208         spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
2209         list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.head, wq.entry) {
2210                 if (!atomic_read(&wrq->done) &&
2211                     nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
2212                         wrq->err = err;
2213                         atomic_set(&wrq->done, 1);
2214                 }
2215                 if (atomic_read(&wrq->done)) {
2216                         wrq->wq.func(&wrq->wq,
2217                                      TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
2218                                      0, NULL);
2219                 }
2220         }
2221         spin_unlock_irqrestore(&sci->sc_wait_request.lock, flags);
2222 }
2223
2224 /**
2225  * nilfs_construct_segment - construct a logical segment
2226  * @sb: super block
2227  *
2228  * Return Value: On success, 0 is returned. On errors, one of the following
2229  * negative error code is returned.
2230  *
2231  * %-EROFS - Read only filesystem.
2232  *
2233  * %-EIO - I/O error
2234  *
2235  * %-ENOSPC - No space left on device (only in a panic state).
2236  *
2237  * %-ERESTARTSYS - Interrupted.
2238  *
2239  * %-ENOMEM - Insufficient memory available.
2240  */
2241 int nilfs_construct_segment(struct super_block *sb)
2242 {
2243         struct the_nilfs *nilfs = sb->s_fs_info;
2244         struct nilfs_sc_info *sci = nilfs->ns_writer;
2245         struct nilfs_transaction_info *ti;
2246
2247         if (sb_rdonly(sb) || unlikely(!sci))
2248                 return -EROFS;
2249
2250         /* A call inside transactions causes a deadlock. */
2251         BUG_ON((ti = current->journal_info) && ti->ti_magic == NILFS_TI_MAGIC);
2252
2253         return nilfs_segctor_sync(sci);
2254 }
2255
2256 /**
2257  * nilfs_construct_dsync_segment - construct a data-only logical segment
2258  * @sb: super block
2259  * @inode: inode whose data blocks should be written out
2260  * @start: start byte offset
2261  * @end: end byte offset (inclusive)
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_dsync_segment(struct super_block *sb, struct inode *inode,
2277                                   loff_t start, loff_t end)
2278 {
2279         struct the_nilfs *nilfs = sb->s_fs_info;
2280         struct nilfs_sc_info *sci = nilfs->ns_writer;
2281         struct nilfs_inode_info *ii;
2282         struct nilfs_transaction_info ti;
2283         int err = 0;
2284
2285         if (sb_rdonly(sb) || unlikely(!sci))
2286                 return -EROFS;
2287
2288         nilfs_transaction_lock(sb, &ti, 0);
2289
2290         ii = NILFS_I(inode);
2291         if (test_bit(NILFS_I_INODE_SYNC, &ii->i_state) ||
2292             nilfs_test_opt(nilfs, STRICT_ORDER) ||
2293             test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2294             nilfs_discontinued(nilfs)) {
2295                 nilfs_transaction_unlock(sb);
2296                 err = nilfs_segctor_sync(sci);
2297                 return err;
2298         }
2299
2300         spin_lock(&nilfs->ns_inode_lock);
2301         if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
2302             !test_bit(NILFS_I_BUSY, &ii->i_state)) {
2303                 spin_unlock(&nilfs->ns_inode_lock);
2304                 nilfs_transaction_unlock(sb);
2305                 return 0;
2306         }
2307         spin_unlock(&nilfs->ns_inode_lock);
2308         sci->sc_dsync_inode = ii;
2309         sci->sc_dsync_start = start;
2310         sci->sc_dsync_end = end;
2311
2312         err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC);
2313         if (!err)
2314                 nilfs->ns_flushed_device = 0;
2315
2316         nilfs_transaction_unlock(sb);
2317         return err;
2318 }
2319
2320 #define FLUSH_FILE_BIT  (0x1) /* data file only */
2321 #define FLUSH_DAT_BIT   BIT(NILFS_DAT_INO) /* DAT only */
2322
2323 /**
2324  * nilfs_segctor_accept - record accepted sequence count of log-write requests
2325  * @sci: segment constructor object
2326  */
2327 static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
2328 {
2329         spin_lock(&sci->sc_state_lock);
2330         sci->sc_seq_accepted = sci->sc_seq_request;
2331         spin_unlock(&sci->sc_state_lock);
2332         del_timer_sync(&sci->sc_timer);
2333 }
2334
2335 /**
2336  * nilfs_segctor_notify - notify the result of request to caller threads
2337  * @sci: segment constructor object
2338  * @mode: mode of log forming
2339  * @err: error code to be notified
2340  */
2341 static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
2342 {
2343         /* Clear requests (even when the construction failed) */
2344         spin_lock(&sci->sc_state_lock);
2345
2346         if (mode == SC_LSEG_SR) {
2347                 sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
2348                 sci->sc_seq_done = sci->sc_seq_accepted;
2349                 nilfs_segctor_wakeup(sci, err);
2350                 sci->sc_flush_request = 0;
2351         } else {
2352                 if (mode == SC_FLUSH_FILE)
2353                         sci->sc_flush_request &= ~FLUSH_FILE_BIT;
2354                 else if (mode == SC_FLUSH_DAT)
2355                         sci->sc_flush_request &= ~FLUSH_DAT_BIT;
2356
2357                 /* re-enable timer if checkpoint creation was not done */
2358                 if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2359                     time_before(jiffies, sci->sc_timer.expires))
2360                         add_timer(&sci->sc_timer);
2361         }
2362         spin_unlock(&sci->sc_state_lock);
2363 }
2364
2365 /**
2366  * nilfs_segctor_construct - form logs and write them to disk
2367  * @sci: segment constructor object
2368  * @mode: mode of log forming
2369  */
2370 static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
2371 {
2372         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2373         struct nilfs_super_block **sbp;
2374         int err = 0;
2375
2376         nilfs_segctor_accept(sci);
2377
2378         if (nilfs_discontinued(nilfs))
2379                 mode = SC_LSEG_SR;
2380         if (!nilfs_segctor_confirm(sci))
2381                 err = nilfs_segctor_do_construct(sci, mode);
2382
2383         if (likely(!err)) {
2384                 if (mode != SC_FLUSH_DAT)
2385                         atomic_set(&nilfs->ns_ndirtyblks, 0);
2386                 if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
2387                     nilfs_discontinued(nilfs)) {
2388                         down_write(&nilfs->ns_sem);
2389                         err = -EIO;
2390                         sbp = nilfs_prepare_super(sci->sc_super,
2391                                                   nilfs_sb_will_flip(nilfs));
2392                         if (likely(sbp)) {
2393                                 nilfs_set_log_cursor(sbp[0], nilfs);
2394                                 err = nilfs_commit_super(sci->sc_super,
2395                                                          NILFS_SB_COMMIT);
2396                         }
2397                         up_write(&nilfs->ns_sem);
2398                 }
2399         }
2400
2401         nilfs_segctor_notify(sci, mode, err);
2402         return err;
2403 }
2404
2405 static void nilfs_construction_timeout(struct timer_list *t)
2406 {
2407         struct nilfs_sc_info *sci = from_timer(sci, t, sc_timer);
2408
2409         wake_up_process(sci->sc_timer_task);
2410 }
2411
2412 static void
2413 nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
2414 {
2415         struct nilfs_inode_info *ii, *n;
2416
2417         list_for_each_entry_safe(ii, n, head, i_dirty) {
2418                 if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
2419                         continue;
2420                 list_del_init(&ii->i_dirty);
2421                 truncate_inode_pages(&ii->vfs_inode.i_data, 0);
2422                 nilfs_btnode_cache_clear(ii->i_assoc_inode->i_mapping);
2423                 iput(&ii->vfs_inode);
2424         }
2425 }
2426
2427 int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
2428                          void **kbufs)
2429 {
2430         struct the_nilfs *nilfs = sb->s_fs_info;
2431         struct nilfs_sc_info *sci = nilfs->ns_writer;
2432         struct nilfs_transaction_info ti;
2433         int err;
2434
2435         if (unlikely(!sci))
2436                 return -EROFS;
2437
2438         nilfs_transaction_lock(sb, &ti, 1);
2439
2440         err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
2441         if (unlikely(err))
2442                 goto out_unlock;
2443
2444         err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
2445         if (unlikely(err)) {
2446                 nilfs_mdt_restore_from_shadow_map(nilfs->ns_dat);
2447                 goto out_unlock;
2448         }
2449
2450         sci->sc_freesegs = kbufs[4];
2451         sci->sc_nfreesegs = argv[4].v_nmembs;
2452         list_splice_tail_init(&nilfs->ns_gc_inodes, &sci->sc_gc_inodes);
2453
2454         for (;;) {
2455                 err = nilfs_segctor_construct(sci, SC_LSEG_SR);
2456                 nilfs_remove_written_gcinodes(nilfs, &sci->sc_gc_inodes);
2457
2458                 if (likely(!err))
2459                         break;
2460
2461                 nilfs_warn(sb, "error %d cleaning segments", err);
2462                 set_current_state(TASK_INTERRUPTIBLE);
2463                 schedule_timeout(sci->sc_interval);
2464         }
2465         if (nilfs_test_opt(nilfs, DISCARD)) {
2466                 int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
2467                                                  sci->sc_nfreesegs);
2468                 if (ret) {
2469                         nilfs_warn(sb,
2470                                    "error %d on discard request, turning discards off for the device",
2471                                    ret);
2472                         nilfs_clear_opt(nilfs, DISCARD);
2473                 }
2474         }
2475
2476  out_unlock:
2477         sci->sc_freesegs = NULL;
2478         sci->sc_nfreesegs = 0;
2479         nilfs_mdt_clear_shadow_map(nilfs->ns_dat);
2480         nilfs_transaction_unlock(sb);
2481         return err;
2482 }
2483
2484 static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
2485 {
2486         struct nilfs_transaction_info ti;
2487
2488         nilfs_transaction_lock(sci->sc_super, &ti, 0);
2489         nilfs_segctor_construct(sci, mode);
2490
2491         /*
2492          * Unclosed segment should be retried.  We do this using sc_timer.
2493          * Timeout of sc_timer will invoke complete construction which leads
2494          * to close the current logical segment.
2495          */
2496         if (test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags))
2497                 nilfs_segctor_start_timer(sci);
2498
2499         nilfs_transaction_unlock(sci->sc_super);
2500 }
2501
2502 static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
2503 {
2504         int mode = 0;
2505
2506         spin_lock(&sci->sc_state_lock);
2507         mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
2508                 SC_FLUSH_DAT : SC_FLUSH_FILE;
2509         spin_unlock(&sci->sc_state_lock);
2510
2511         if (mode) {
2512                 nilfs_segctor_do_construct(sci, mode);
2513
2514                 spin_lock(&sci->sc_state_lock);
2515                 sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
2516                         ~FLUSH_FILE_BIT : ~FLUSH_DAT_BIT;
2517                 spin_unlock(&sci->sc_state_lock);
2518         }
2519         clear_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
2520 }
2521
2522 static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
2523 {
2524         if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2525             time_before(jiffies, sci->sc_lseg_stime + sci->sc_mjcp_freq)) {
2526                 if (!(sci->sc_flush_request & ~FLUSH_FILE_BIT))
2527                         return SC_FLUSH_FILE;
2528                 else if (!(sci->sc_flush_request & ~FLUSH_DAT_BIT))
2529                         return SC_FLUSH_DAT;
2530         }
2531         return SC_LSEG_SR;
2532 }
2533
2534 /**
2535  * nilfs_segctor_thread - main loop of the segment constructor thread.
2536  * @arg: pointer to a struct nilfs_sc_info.
2537  *
2538  * nilfs_segctor_thread() initializes a timer and serves as a daemon
2539  * to execute segment constructions.
2540  */
2541 static int nilfs_segctor_thread(void *arg)
2542 {
2543         struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
2544         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2545         int timeout = 0;
2546
2547         sci->sc_timer_task = current;
2548
2549         /* start sync. */
2550         sci->sc_task = current;
2551         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_start_thread() */
2552         nilfs_info(sci->sc_super,
2553                    "segctord starting. Construction interval = %lu seconds, CP frequency < %lu seconds",
2554                    sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
2555
2556         spin_lock(&sci->sc_state_lock);
2557  loop:
2558         for (;;) {
2559                 int mode;
2560
2561                 if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2562                         goto end_thread;
2563
2564                 if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2565                         mode = SC_LSEG_SR;
2566                 else if (sci->sc_flush_request)
2567                         mode = nilfs_segctor_flush_mode(sci);
2568                 else
2569                         break;
2570
2571                 spin_unlock(&sci->sc_state_lock);
2572                 nilfs_segctor_thread_construct(sci, mode);
2573                 spin_lock(&sci->sc_state_lock);
2574                 timeout = 0;
2575         }
2576
2577
2578         if (freezing(current)) {
2579                 spin_unlock(&sci->sc_state_lock);
2580                 try_to_freeze();
2581                 spin_lock(&sci->sc_state_lock);
2582         } else {
2583                 DEFINE_WAIT(wait);
2584                 int should_sleep = 1;
2585
2586                 prepare_to_wait(&sci->sc_wait_daemon, &wait,
2587                                 TASK_INTERRUPTIBLE);
2588
2589                 if (sci->sc_seq_request != sci->sc_seq_done)
2590                         should_sleep = 0;
2591                 else if (sci->sc_flush_request)
2592                         should_sleep = 0;
2593                 else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2594                         should_sleep = time_before(jiffies,
2595                                         sci->sc_timer.expires);
2596
2597                 if (should_sleep) {
2598                         spin_unlock(&sci->sc_state_lock);
2599                         schedule();
2600                         spin_lock(&sci->sc_state_lock);
2601                 }
2602                 finish_wait(&sci->sc_wait_daemon, &wait);
2603                 timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2604                            time_after_eq(jiffies, sci->sc_timer.expires));
2605
2606                 if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2607                         set_nilfs_discontinued(nilfs);
2608         }
2609         goto loop;
2610
2611  end_thread:
2612         spin_unlock(&sci->sc_state_lock);
2613
2614         /* end sync. */
2615         sci->sc_task = NULL;
2616         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
2617         return 0;
2618 }
2619
2620 static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2621 {
2622         struct task_struct *t;
2623
2624         t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2625         if (IS_ERR(t)) {
2626                 int err = PTR_ERR(t);
2627
2628                 nilfs_err(sci->sc_super, "error %d creating segctord thread",
2629                           err);
2630                 return err;
2631         }
2632         wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2633         return 0;
2634 }
2635
2636 static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2637         __acquires(&sci->sc_state_lock)
2638         __releases(&sci->sc_state_lock)
2639 {
2640         sci->sc_state |= NILFS_SEGCTOR_QUIT;
2641
2642         while (sci->sc_task) {
2643                 wake_up(&sci->sc_wait_daemon);
2644                 spin_unlock(&sci->sc_state_lock);
2645                 wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2646                 spin_lock(&sci->sc_state_lock);
2647         }
2648 }
2649
2650 /*
2651  * Setup & clean-up functions
2652  */
2653 static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
2654                                                struct nilfs_root *root)
2655 {
2656         struct the_nilfs *nilfs = sb->s_fs_info;
2657         struct nilfs_sc_info *sci;
2658
2659         sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2660         if (!sci)
2661                 return NULL;
2662
2663         sci->sc_super = sb;
2664
2665         nilfs_get_root(root);
2666         sci->sc_root = root;
2667
2668         init_waitqueue_head(&sci->sc_wait_request);
2669         init_waitqueue_head(&sci->sc_wait_daemon);
2670         init_waitqueue_head(&sci->sc_wait_task);
2671         spin_lock_init(&sci->sc_state_lock);
2672         INIT_LIST_HEAD(&sci->sc_dirty_files);
2673         INIT_LIST_HEAD(&sci->sc_segbufs);
2674         INIT_LIST_HEAD(&sci->sc_write_logs);
2675         INIT_LIST_HEAD(&sci->sc_gc_inodes);
2676         INIT_LIST_HEAD(&sci->sc_iput_queue);
2677         INIT_WORK(&sci->sc_iput_work, nilfs_iput_work_func);
2678         timer_setup(&sci->sc_timer, nilfs_construction_timeout, 0);
2679
2680         sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2681         sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2682         sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2683
2684         if (nilfs->ns_interval)
2685                 sci->sc_interval = HZ * nilfs->ns_interval;
2686         if (nilfs->ns_watermark)
2687                 sci->sc_watermark = nilfs->ns_watermark;
2688         return sci;
2689 }
2690
2691 static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2692 {
2693         int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2694
2695         /*
2696          * The segctord thread was stopped and its timer was removed.
2697          * But some tasks remain.
2698          */
2699         do {
2700                 struct nilfs_transaction_info ti;
2701
2702                 nilfs_transaction_lock(sci->sc_super, &ti, 0);
2703                 ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2704                 nilfs_transaction_unlock(sci->sc_super);
2705
2706                 flush_work(&sci->sc_iput_work);
2707
2708         } while (ret && retrycount-- > 0);
2709 }
2710
2711 /**
2712  * nilfs_segctor_destroy - destroy the segment constructor.
2713  * @sci: nilfs_sc_info
2714  *
2715  * nilfs_segctor_destroy() kills the segctord thread and frees
2716  * the nilfs_sc_info struct.
2717  * Caller must hold the segment semaphore.
2718  */
2719 static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2720 {
2721         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2722         int flag;
2723
2724         up_write(&nilfs->ns_segctor_sem);
2725
2726         spin_lock(&sci->sc_state_lock);
2727         nilfs_segctor_kill_thread(sci);
2728         flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2729                 || sci->sc_seq_request != sci->sc_seq_done);
2730         spin_unlock(&sci->sc_state_lock);
2731
2732         if (flush_work(&sci->sc_iput_work))
2733                 flag = true;
2734
2735         if (flag || !nilfs_segctor_confirm(sci))
2736                 nilfs_segctor_write_out(sci);
2737
2738         if (!list_empty(&sci->sc_dirty_files)) {
2739                 nilfs_warn(sci->sc_super,
2740                            "disposed unprocessed dirty file(s) when stopping log writer");
2741                 nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2742         }
2743
2744         if (!list_empty(&sci->sc_iput_queue)) {
2745                 nilfs_warn(sci->sc_super,
2746                            "disposed unprocessed inode(s) in iput queue when stopping log writer");
2747                 nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 1);
2748         }
2749
2750         WARN_ON(!list_empty(&sci->sc_segbufs));
2751         WARN_ON(!list_empty(&sci->sc_write_logs));
2752
2753         nilfs_put_root(sci->sc_root);
2754
2755         down_write(&nilfs->ns_segctor_sem);
2756
2757         timer_shutdown_sync(&sci->sc_timer);
2758         kfree(sci);
2759 }
2760
2761 /**
2762  * nilfs_attach_log_writer - attach log writer
2763  * @sb: super block instance
2764  * @root: root object of the current filesystem tree
2765  *
2766  * This allocates a log writer object, initializes it, and starts the
2767  * log writer.
2768  *
2769  * Return Value: On success, 0 is returned. On error, one of the following
2770  * negative error code is returned.
2771  *
2772  * %-ENOMEM - Insufficient memory available.
2773  */
2774 int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
2775 {
2776         struct the_nilfs *nilfs = sb->s_fs_info;
2777         int err;
2778
2779         if (nilfs->ns_writer) {
2780                 /*
2781                  * This happens if the filesystem is made read-only by
2782                  * __nilfs_error or nilfs_remount and then remounted
2783                  * read/write.  In these cases, reuse the existing
2784                  * writer.
2785                  */
2786                 return 0;
2787         }
2788
2789         nilfs->ns_writer = nilfs_segctor_new(sb, root);
2790         if (!nilfs->ns_writer)
2791                 return -ENOMEM;
2792
2793         inode_attach_wb(nilfs->ns_bdev->bd_inode, NULL);
2794
2795         err = nilfs_segctor_start_thread(nilfs->ns_writer);
2796         if (unlikely(err))
2797                 nilfs_detach_log_writer(sb);
2798
2799         return err;
2800 }
2801
2802 /**
2803  * nilfs_detach_log_writer - destroy log writer
2804  * @sb: super block instance
2805  *
2806  * This kills log writer daemon, frees the log writer object, and
2807  * destroys list of dirty files.
2808  */
2809 void nilfs_detach_log_writer(struct super_block *sb)
2810 {
2811         struct the_nilfs *nilfs = sb->s_fs_info;
2812         LIST_HEAD(garbage_list);
2813
2814         down_write(&nilfs->ns_segctor_sem);
2815         if (nilfs->ns_writer) {
2816                 nilfs_segctor_destroy(nilfs->ns_writer);
2817                 nilfs->ns_writer = NULL;
2818         }
2819
2820         /* Force to free the list of dirty files */
2821         spin_lock(&nilfs->ns_inode_lock);
2822         if (!list_empty(&nilfs->ns_dirty_files)) {
2823                 list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2824                 nilfs_warn(sb,
2825                            "disposed unprocessed dirty file(s) when detaching log writer");
2826         }
2827         spin_unlock(&nilfs->ns_inode_lock);
2828         up_write(&nilfs->ns_segctor_sem);
2829
2830         nilfs_dispose_list(nilfs, &garbage_list, 1);
2831 }