fs/nilfs2/segment.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * NILFS segment constructor.
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Written by Ryusuke Konishi.
   8  *
   9  */
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/buffer_head.h>
  13 #include <linux/writeback.h>
  14 #include <linux/bitops.h>
  15 #include <linux/bio.h>
  16 #include <linux/completion.h>
  17 #include <linux/blkdev.h>
  18 #include <linux/backing-dev.h>
  19 #include <linux/freezer.h>
  20 #include <linux/kthread.h>
  21 #include <linux/crc32.h>
  22 #include <linux/pagevec.h>
  23 #include <linux/slab.h>
  24 #include <linux/sched/signal.h>
  25
  26 #include "nilfs.h"
  27 #include "btnode.h"
  28 #include "page.h"
  29 #include "segment.h"
  30 #include "sufile.h"
  31 #include "cpfile.h"
  32 #include "ifile.h"
  33 #include "segbuf.h"
  34
  35
  36 /*
  37  * Segment constructor
  38  */
  39 #define SC_N_INODEVEC   16   /* Size of locally allocated inode vector */
  40
  41 #define SC_MAX_SEGDELTA 64   /*
  42                               * Upper limit of the number of segments
  43                               * appended in collection retry loop
  44                               */
  45
  46 /* Construction mode */
  47 enum {
  48         SC_LSEG_SR = 1, /* Make a logical segment having a super root */
  49         SC_LSEG_DSYNC,  /*
  50                          * Flush data blocks of a given file and make
  51                          * a logical segment without a super root.
  52                          */
  53         SC_FLUSH_FILE,  /*
  54                          * Flush data files, leads to segment writes without
  55                          * creating a checkpoint.
  56                          */
  57         SC_FLUSH_DAT,   /*
  58                          * Flush DAT file.  This also creates segments
  59                          * without a checkpoint.
  60                          */
  61 };
  62
  63 /* Stage numbers of dirty block collection */
  64 enum {
  65         NILFS_ST_INIT = 0,
  66         NILFS_ST_GC,            /* Collecting dirty blocks for GC */
  67         NILFS_ST_FILE,
  68         NILFS_ST_IFILE,
  69         NILFS_ST_CPFILE,
  70         NILFS_ST_SUFILE,
  71         NILFS_ST_DAT,
  72         NILFS_ST_SR,            /* Super root */
  73         NILFS_ST_DSYNC,         /* Data sync blocks */
  74         NILFS_ST_DONE,
  75 };
  76
  77 #define CREATE_TRACE_POINTS
  78 #include <trace/events/nilfs2.h>
  79
  80 /*
  81  * nilfs_sc_cstage_inc(), nilfs_sc_cstage_set(), nilfs_sc_cstage_get() are
  82  * wrapper functions of stage count (nilfs_sc_info->sc_stage.scnt). Users of
  83  * the variable must use them because transition of stage count must involve
  84  * trace events (trace_nilfs2_collection_stage_transition).
  85  *
  86  * nilfs_sc_cstage_get() isn't required for the above purpose because it doesn't
  87  * produce tracepoint events. It is provided just for making the intention
  88  * clear.
  89  */
  90 static inline void nilfs_sc_cstage_inc(struct nilfs_sc_info *sci)
  91 {
  92         sci->sc_stage.scnt++;
  93         trace_nilfs2_collection_stage_transition(sci);
  94 }
  95
  96 static inline void nilfs_sc_cstage_set(struct nilfs_sc_info *sci, int next_scnt)
  97 {
  98         sci->sc_stage.scnt = next_scnt;
  99         trace_nilfs2_collection_stage_transition(sci);
 100 }
 101
 102 static inline int nilfs_sc_cstage_get(struct nilfs_sc_info *sci)
 103 {
 104         return sci->sc_stage.scnt;
 105 }
 106
 107 /* State flags of collection */
 108 #define NILFS_CF_NODE           0x0001  /* Collecting node blocks */
 109 #define NILFS_CF_IFILE_STARTED  0x0002  /* IFILE stage has started */
 110 #define NILFS_CF_SUFREED        0x0004  /* segment usages has been freed */
 111 #define NILFS_CF_HISTORY_MASK   (NILFS_CF_IFILE_STARTED | NILFS_CF_SUFREED)
 112
 113 /* Operations depending on the construction mode and file type */
 114 struct nilfs_sc_operations {
 115         int (*collect_data)(struct nilfs_sc_info *, struct buffer_head *,
 116                             struct inode *);
 117         int (*collect_node)(struct nilfs_sc_info *, struct buffer_head *,
 118                             struct inode *);
 119         int (*collect_bmap)(struct nilfs_sc_info *, struct buffer_head *,
 120                             struct inode *);
 121         void (*write_data_binfo)(struct nilfs_sc_info *,
 122                                  struct nilfs_segsum_pointer *,
 123                                  union nilfs_binfo *);
 124         void (*write_node_binfo)(struct nilfs_sc_info *,
 125                                  struct nilfs_segsum_pointer *,
 126                                  union nilfs_binfo *);
 127 };
 128
 129 /*
 130  * Other definitions
 131  */
 132 static void nilfs_segctor_start_timer(struct nilfs_sc_info *);
 133 static void nilfs_segctor_do_flush(struct nilfs_sc_info *, int);
 134 static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *);
 135 static void nilfs_dispose_list(struct the_nilfs *, struct list_head *, int);
 136
 137 #define nilfs_cnt32_ge(a, b)   \
 138         (typecheck(__u32, a) && typecheck(__u32, b) && \
 139          ((__s32)(a) - (__s32)(b) >= 0))
 140
 141 static int nilfs_prepare_segment_lock(struct super_block *sb,
 142                                       struct nilfs_transaction_info *ti)
 143 {
 144         struct nilfs_transaction_info *cur_ti = current->journal_info;
 145         void *save = NULL;
 146
 147         if (cur_ti) {
 148                 if (cur_ti->ti_magic == NILFS_TI_MAGIC)
 149                         return ++cur_ti->ti_count;
 150
 151                 /*
 152                  * If journal_info field is occupied by other FS,
 153                  * it is saved and will be restored on
 154                  * nilfs_transaction_commit().
 155                  */
 156                 nilfs_warn(sb, "journal info from a different FS");
 157                 save = current->journal_info;
 158         }
 159         if (!ti) {
 160                 ti = kmem_cache_alloc(nilfs_transaction_cachep, GFP_NOFS);
 161                 if (!ti)
 162                         return -ENOMEM;
 163                 ti->ti_flags = NILFS_TI_DYNAMIC_ALLOC;
 164         } else {
 165                 ti->ti_flags = 0;
 166         }
 167         ti->ti_count = 0;
 168         ti->ti_save = save;
 169         ti->ti_magic = NILFS_TI_MAGIC;
 170         current->journal_info = ti;
 171         return 0;
 172 }
 173
 174 /**
 175  * nilfs_transaction_begin - start indivisible file operations.
 176  * @sb: super block
 177  * @ti: nilfs_transaction_info
 178  * @vacancy_check: flags for vacancy rate checks
 179  *
 180  * nilfs_transaction_begin() acquires a reader/writer semaphore, called
 181  * the segment semaphore, to make a segment construction and write tasks
 182  * exclusive.  The function is used with nilfs_transaction_commit() in pairs.
 183  * The region enclosed by these two functions can be nested.  To avoid a
 184  * deadlock, the semaphore is only acquired or released in the outermost call.
 185  *
 186  * This function allocates a nilfs_transaction_info struct to keep context
 187  * information on it.  It is initialized and hooked onto the current task in
 188  * the outermost call.  If a pre-allocated struct is given to @ti, it is used
 189  * instead; otherwise a new struct is assigned from a slab.
 190  *
 191  * When @vacancy_check flag is set, this function will check the amount of
 192  * free space, and will wait for the GC to reclaim disk space if low capacity.
 193  *
 194  * Return Value: On success, 0 is returned. On error, one of the following
 195  * negative error code is returned.
 196  *
 197  * %-ENOMEM - Insufficient memory available.
 198  *
 199  * %-ENOSPC - No space left on device
 200  */
 201 int nilfs_transaction_begin(struct super_block *sb,
 202                             struct nilfs_transaction_info *ti,
 203                             int vacancy_check)
 204 {
 205         struct the_nilfs *nilfs;
 206         int ret = nilfs_prepare_segment_lock(sb, ti);
 207         struct nilfs_transaction_info *trace_ti;
 208
 209         if (unlikely(ret < 0))
 210                 return ret;
 211         if (ret > 0) {
 212                 trace_ti = current->journal_info;
 213
 214                 trace_nilfs2_transaction_transition(sb, trace_ti,
 215                                     trace_ti->ti_count, trace_ti->ti_flags,
 216                                     TRACE_NILFS2_TRANSACTION_BEGIN);
 217                 return 0;
 218         }
 219
 220         sb_start_intwrite(sb);
 221
 222         nilfs = sb->s_fs_info;
 223         down_read(&nilfs->ns_segctor_sem);
 224         if (vacancy_check && nilfs_near_disk_full(nilfs)) {
 225                 up_read(&nilfs->ns_segctor_sem);
 226                 ret = -ENOSPC;
 227                 goto failed;
 228         }
 229
 230         trace_ti = current->journal_info;
 231         trace_nilfs2_transaction_transition(sb, trace_ti, trace_ti->ti_count,
 232                                             trace_ti->ti_flags,
 233                                             TRACE_NILFS2_TRANSACTION_BEGIN);
 234         return 0;
 235
 236  failed:
 237         ti = current->journal_info;
 238         current->journal_info = ti->ti_save;
 239         if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 240                 kmem_cache_free(nilfs_transaction_cachep, ti);
 241         sb_end_intwrite(sb);
 242         return ret;
 243 }
 244
 245 /**
 246  * nilfs_transaction_commit - commit indivisible file operations.
 247  * @sb: super block
 248  *
 249  * nilfs_transaction_commit() releases the read semaphore which is
 250  * acquired by nilfs_transaction_begin(). This is only performed
 251  * in outermost call of this function.  If a commit flag is set,
 252  * nilfs_transaction_commit() sets a timer to start the segment
 253  * constructor.  If a sync flag is set, it starts construction
 254  * directly.
 255  */
 256 int nilfs_transaction_commit(struct super_block *sb)
 257 {
 258         struct nilfs_transaction_info *ti = current->journal_info;
 259         struct the_nilfs *nilfs = sb->s_fs_info;
 260         int err = 0;
 261
 262         BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 263         ti->ti_flags |= NILFS_TI_COMMIT;
 264         if (ti->ti_count > 0) {
 265                 ti->ti_count--;
 266                 trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 267                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
 268                 return 0;
 269         }
 270         if (nilfs->ns_writer) {
 271                 struct nilfs_sc_info *sci = nilfs->ns_writer;
 272
 273                 if (ti->ti_flags & NILFS_TI_COMMIT)
 274                         nilfs_segctor_start_timer(sci);
 275                 if (atomic_read(&nilfs->ns_ndirtyblks) > sci->sc_watermark)
 276                         nilfs_segctor_do_flush(sci, 0);
 277         }
 278         up_read(&nilfs->ns_segctor_sem);
 279         trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 280                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
 281
 282         current->journal_info = ti->ti_save;
 283
 284         if (ti->ti_flags & NILFS_TI_SYNC)
 285                 err = nilfs_construct_segment(sb);
 286         if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 287                 kmem_cache_free(nilfs_transaction_cachep, ti);
 288         sb_end_intwrite(sb);
 289         return err;
 290 }
 291
 292 void nilfs_transaction_abort(struct super_block *sb)
 293 {
 294         struct nilfs_transaction_info *ti = current->journal_info;
 295         struct the_nilfs *nilfs = sb->s_fs_info;
 296
 297         BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 298         if (ti->ti_count > 0) {
 299                 ti->ti_count--;
 300                 trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 301                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
 302                 return;
 303         }
 304         up_read(&nilfs->ns_segctor_sem);
 305
 306         trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 307                     ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
 308
 309         current->journal_info = ti->ti_save;
 310         if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 311                 kmem_cache_free(nilfs_transaction_cachep, ti);
 312         sb_end_intwrite(sb);
 313 }
 314
 315 void nilfs_relax_pressure_in_lock(struct super_block *sb)
 316 {
 317         struct the_nilfs *nilfs = sb->s_fs_info;
 318         struct nilfs_sc_info *sci = nilfs->ns_writer;
 319
 320         if (sb_rdonly(sb) || unlikely(!sci) || !sci->sc_flush_request)
 321                 return;
 322
 323         set_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
 324         up_read(&nilfs->ns_segctor_sem);
 325
 326         down_write(&nilfs->ns_segctor_sem);
 327         if (sci->sc_flush_request &&
 328             test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags)) {
 329                 struct nilfs_transaction_info *ti = current->journal_info;
 330
 331                 ti->ti_flags |= NILFS_TI_WRITER;
 332                 nilfs_segctor_do_immediate_flush(sci);
 333                 ti->ti_flags &= ~NILFS_TI_WRITER;
 334         }
 335         downgrade_write(&nilfs->ns_segctor_sem);
 336 }
 337
 338 static void nilfs_transaction_lock(struct super_block *sb,
 339                                    struct nilfs_transaction_info *ti,
 340                                    int gcflag)
 341 {
 342         struct nilfs_transaction_info *cur_ti = current->journal_info;
 343         struct the_nilfs *nilfs = sb->s_fs_info;
 344         struct nilfs_sc_info *sci = nilfs->ns_writer;
 345
 346         WARN_ON(cur_ti);
 347         ti->ti_flags = NILFS_TI_WRITER;
 348         ti->ti_count = 0;
 349         ti->ti_save = cur_ti;
 350         ti->ti_magic = NILFS_TI_MAGIC;
 351         current->journal_info = ti;
 352
 353         for (;;) {
 354                 trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 355                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_TRYLOCK);
 356
 357                 down_write(&nilfs->ns_segctor_sem);
 358                 if (!test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags))
 359                         break;
 360
 361                 nilfs_segctor_do_immediate_flush(sci);
 362
 363                 up_write(&nilfs->ns_segctor_sem);
 364                 cond_resched();
 365         }
 366         if (gcflag)
 367                 ti->ti_flags |= NILFS_TI_GC;
 368
 369         trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 370                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_LOCK);
 371 }
 372
 373 static void nilfs_transaction_unlock(struct super_block *sb)
 374 {
 375         struct nilfs_transaction_info *ti = current->journal_info;
 376         struct the_nilfs *nilfs = sb->s_fs_info;
 377
 378         BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 379         BUG_ON(ti->ti_count > 0);
 380
 381         up_write(&nilfs->ns_segctor_sem);
 382         current->journal_info = ti->ti_save;
 383
 384         trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 385                             ti->ti_flags, TRACE_NILFS2_TRANSACTION_UNLOCK);
 386 }
 387
 388 static void *nilfs_segctor_map_segsum_entry(struct nilfs_sc_info *sci,
 389                                             struct nilfs_segsum_pointer *ssp,
 390                                             unsigned int bytes)
 391 {
 392         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 393         unsigned int blocksize = sci->sc_super->s_blocksize;
 394         void *p;
 395
 396         if (unlikely(ssp->offset + bytes > blocksize)) {
 397                 ssp->offset = 0;
 398                 BUG_ON(NILFS_SEGBUF_BH_IS_LAST(ssp->bh,
 399                                                &segbuf->sb_segsum_buffers));
 400                 ssp->bh = NILFS_SEGBUF_NEXT_BH(ssp->bh);
 401         }
 402         p = ssp->bh->b_data + ssp->offset;
 403         ssp->offset += bytes;
 404         return p;
 405 }
 406
 407 /**
 408  * nilfs_segctor_reset_segment_buffer - reset the current segment buffer
 409  * @sci: nilfs_sc_info
 410  */
 411 static int nilfs_segctor_reset_segment_buffer(struct nilfs_sc_info *sci)
 412 {
 413         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 414         struct buffer_head *sumbh;
 415         unsigned int sumbytes;
 416         unsigned int flags = 0;
 417         int err;
 418
 419         if (nilfs_doing_gc())
 420                 flags = NILFS_SS_GC;
 421         err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime, sci->sc_cno);
 422         if (unlikely(err))
 423                 return err;
 424
 425         sumbh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
 426         sumbytes = segbuf->sb_sum.sumbytes;
 427         sci->sc_finfo_ptr.bh = sumbh;  sci->sc_finfo_ptr.offset = sumbytes;
 428         sci->sc_binfo_ptr.bh = sumbh;  sci->sc_binfo_ptr.offset = sumbytes;
 429         sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 430         return 0;
 431 }
 432
 433 /**
 434  * nilfs_segctor_zeropad_segsum - zero pad the rest of the segment summary area
 435  * @sci: segment constructor object
 436  *
 437  * nilfs_segctor_zeropad_segsum() zero-fills unallocated space at the end of
 438  * the current segment summary block.
 439  */
 440 static void nilfs_segctor_zeropad_segsum(struct nilfs_sc_info *sci)
 441 {
 442         struct nilfs_segsum_pointer *ssp;
 443
 444         ssp = sci->sc_blk_cnt > 0 ? &sci->sc_binfo_ptr : &sci->sc_finfo_ptr;
 445         if (ssp->offset < ssp->bh->b_size)
 446                 memset(ssp->bh->b_data + ssp->offset, 0,
 447                        ssp->bh->b_size - ssp->offset);
 448 }
 449
 450 static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
 451 {
 452         sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
 453         if (NILFS_SEGBUF_IS_LAST(sci->sc_curseg, &sci->sc_segbufs))
 454                 return -E2BIG; /*
 455                                 * The current segment is filled up
 456                                 * (internal code)
 457                                 */
 458         nilfs_segctor_zeropad_segsum(sci);
 459         sci->sc_curseg = NILFS_NEXT_SEGBUF(sci->sc_curseg);
 460         return nilfs_segctor_reset_segment_buffer(sci);
 461 }
 462
 463 static int nilfs_segctor_add_super_root(struct nilfs_sc_info *sci)
 464 {
 465         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 466         int err;
 467
 468         if (segbuf->sb_sum.nblocks >= segbuf->sb_rest_blocks) {
 469                 err = nilfs_segctor_feed_segment(sci);
 470                 if (err)
 471                         return err;
 472                 segbuf = sci->sc_curseg;
 473         }
 474         err = nilfs_segbuf_extend_payload(segbuf, &segbuf->sb_super_root);
 475         if (likely(!err))
 476                 segbuf->sb_sum.flags |= NILFS_SS_SR;
 477         return err;
 478 }
 479
 480 /*
 481  * Functions for making segment summary and payloads
 482  */
 483 static int nilfs_segctor_segsum_block_required(
 484         struct nilfs_sc_info *sci, const struct nilfs_segsum_pointer *ssp,
 485         unsigned int binfo_size)
 486 {
 487         unsigned int blocksize = sci->sc_super->s_blocksize;
 488         /* Size of finfo and binfo is enough small against blocksize */
 489
 490         return ssp->offset + binfo_size +
 491                 (!sci->sc_blk_cnt ? sizeof(struct nilfs_finfo) : 0) >
 492                 blocksize;
 493 }
 494
 495 static void nilfs_segctor_begin_finfo(struct nilfs_sc_info *sci,
 496                                       struct inode *inode)
 497 {
 498         sci->sc_curseg->sb_sum.nfinfo++;
 499         sci->sc_binfo_ptr = sci->sc_finfo_ptr;
 500         nilfs_segctor_map_segsum_entry(
 501                 sci, &sci->sc_binfo_ptr, sizeof(struct nilfs_finfo));
 502
 503         if (NILFS_I(inode)->i_root &&
 504             !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 505                 set_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
 506         /* skip finfo */
 507 }
 508
 509 static void nilfs_segctor_end_finfo(struct nilfs_sc_info *sci,
 510                                     struct inode *inode)
 511 {
 512         struct nilfs_finfo *finfo;
 513         struct nilfs_inode_info *ii;
 514         struct nilfs_segment_buffer *segbuf;
 515         __u64 cno;
 516
 517         if (sci->sc_blk_cnt == 0)
 518                 return;
 519
 520         ii = NILFS_I(inode);
 521
 522         if (test_bit(NILFS_I_GCINODE, &ii->i_state))
 523                 cno = ii->i_cno;
 524         else if (NILFS_ROOT_METADATA_FILE(inode->i_ino))
 525                 cno = 0;
 526         else
 527                 cno = sci->sc_cno;
 528
 529         finfo = nilfs_segctor_map_segsum_entry(sci, &sci->sc_finfo_ptr,
 530                                                  sizeof(*finfo));
 531         finfo->fi_ino = cpu_to_le64(inode->i_ino);
 532         finfo->fi_nblocks = cpu_to_le32(sci->sc_blk_cnt);
 533         finfo->fi_ndatablk = cpu_to_le32(sci->sc_datablk_cnt);
 534         finfo->fi_cno = cpu_to_le64(cno);
 535
 536         segbuf = sci->sc_curseg;
 537         segbuf->sb_sum.sumbytes = sci->sc_binfo_ptr.offset +
 538                 sci->sc_super->s_blocksize * (segbuf->sb_sum.nsumblk - 1);
 539         sci->sc_finfo_ptr = sci->sc_binfo_ptr;
 540         sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 541 }
 542
 543 static int nilfs_segctor_add_file_block(struct nilfs_sc_info *sci,
 544                                         struct buffer_head *bh,
 545                                         struct inode *inode,
 546                                         unsigned int binfo_size)
 547 {
 548         struct nilfs_segment_buffer *segbuf;
 549         int required, err = 0;
 550
 551  retry:
 552         segbuf = sci->sc_curseg;
 553         required = nilfs_segctor_segsum_block_required(
 554                 sci, &sci->sc_binfo_ptr, binfo_size);
 555         if (segbuf->sb_sum.nblocks + required + 1 > segbuf->sb_rest_blocks) {
 556                 nilfs_segctor_end_finfo(sci, inode);
 557                 err = nilfs_segctor_feed_segment(sci);
 558                 if (err)
 559                         return err;
 560                 goto retry;
 561         }
 562         if (unlikely(required)) {
 563                 nilfs_segctor_zeropad_segsum(sci);
 564                 err = nilfs_segbuf_extend_segsum(segbuf);
 565                 if (unlikely(err))
 566                         goto failed;
 567         }
 568         if (sci->sc_blk_cnt == 0)
 569                 nilfs_segctor_begin_finfo(sci, inode);
 570
 571         nilfs_segctor_map_segsum_entry(sci, &sci->sc_binfo_ptr, binfo_size);
 572         /* Substitution to vblocknr is delayed until update_blocknr() */
 573         nilfs_segbuf_add_file_buffer(segbuf, bh);
 574         sci->sc_blk_cnt++;
 575  failed:
 576         return err;
 577 }
 578
 579 /*
 580  * Callback functions that enumerate, mark, and collect dirty blocks
 581  */
 582 static int nilfs_collect_file_data(struct nilfs_sc_info *sci,
 583                                    struct buffer_head *bh, struct inode *inode)
 584 {
 585         int err;
 586
 587         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 588         if (err < 0)
 589                 return err;
 590
 591         err = nilfs_segctor_add_file_block(sci, bh, inode,
 592                                            sizeof(struct nilfs_binfo_v));
 593         if (!err)
 594                 sci->sc_datablk_cnt++;
 595         return err;
 596 }
 597
 598 static int nilfs_collect_file_node(struct nilfs_sc_info *sci,
 599                                    struct buffer_head *bh,
 600                                    struct inode *inode)
 601 {
 602         return nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 603 }
 604
 605 static int nilfs_collect_file_bmap(struct nilfs_sc_info *sci,
 606                                    struct buffer_head *bh,
 607                                    struct inode *inode)
 608 {
 609         WARN_ON(!buffer_dirty(bh));
 610         return nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 611 }
 612
 613 static void nilfs_write_file_data_binfo(struct nilfs_sc_info *sci,
 614                                         struct nilfs_segsum_pointer *ssp,
 615                                         union nilfs_binfo *binfo)
 616 {
 617         struct nilfs_binfo_v *binfo_v = nilfs_segctor_map_segsum_entry(
 618                 sci, ssp, sizeof(*binfo_v));
 619         *binfo_v = binfo->bi_v;
 620 }
 621
 622 static void nilfs_write_file_node_binfo(struct nilfs_sc_info *sci,
 623                                         struct nilfs_segsum_pointer *ssp,
 624                                         union nilfs_binfo *binfo)
 625 {
 626         __le64 *vblocknr = nilfs_segctor_map_segsum_entry(
 627                 sci, ssp, sizeof(*vblocknr));
 628         *vblocknr = binfo->bi_v.bi_vblocknr;
 629 }
 630
 631 static const struct nilfs_sc_operations nilfs_sc_file_ops = {
 632         .collect_data = nilfs_collect_file_data,
 633         .collect_node = nilfs_collect_file_node,
 634         .collect_bmap = nilfs_collect_file_bmap,
 635         .write_data_binfo = nilfs_write_file_data_binfo,
 636         .write_node_binfo = nilfs_write_file_node_binfo,
 637 };
 638
 639 static int nilfs_collect_dat_data(struct nilfs_sc_info *sci,
 640                                   struct buffer_head *bh, struct inode *inode)
 641 {
 642         int err;
 643
 644         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 645         if (err < 0)
 646                 return err;
 647
 648         err = nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 649         if (!err)
 650                 sci->sc_datablk_cnt++;
 651         return err;
 652 }
 653
 654 static int nilfs_collect_dat_bmap(struct nilfs_sc_info *sci,
 655                                   struct buffer_head *bh, struct inode *inode)
 656 {
 657         WARN_ON(!buffer_dirty(bh));
 658         return nilfs_segctor_add_file_block(sci, bh, inode,
 659                                             sizeof(struct nilfs_binfo_dat));
 660 }
 661
 662 static void nilfs_write_dat_data_binfo(struct nilfs_sc_info *sci,
 663                                        struct nilfs_segsum_pointer *ssp,
 664                                        union nilfs_binfo *binfo)
 665 {
 666         __le64 *blkoff = nilfs_segctor_map_segsum_entry(sci, ssp,
 667                                                           sizeof(*blkoff));
 668         *blkoff = binfo->bi_dat.bi_blkoff;
 669 }
 670
 671 static void nilfs_write_dat_node_binfo(struct nilfs_sc_info *sci,
 672                                        struct nilfs_segsum_pointer *ssp,
 673                                        union nilfs_binfo *binfo)
 674 {
 675         struct nilfs_binfo_dat *binfo_dat =
 676                 nilfs_segctor_map_segsum_entry(sci, ssp, sizeof(*binfo_dat));
 677         *binfo_dat = binfo->bi_dat;
 678 }
 679
 680 static const struct nilfs_sc_operations nilfs_sc_dat_ops = {
 681         .collect_data = nilfs_collect_dat_data,
 682         .collect_node = nilfs_collect_file_node,
 683         .collect_bmap = nilfs_collect_dat_bmap,
 684         .write_data_binfo = nilfs_write_dat_data_binfo,
 685         .write_node_binfo = nilfs_write_dat_node_binfo,
 686 };
 687
 688 static const struct nilfs_sc_operations nilfs_sc_dsync_ops = {
 689         .collect_data = nilfs_collect_file_data,
 690         .collect_node = NULL,
 691         .collect_bmap = NULL,
 692         .write_data_binfo = nilfs_write_file_data_binfo,
 693         .write_node_binfo = NULL,
 694 };
 695
 696 static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode,
 697                                               struct list_head *listp,
 698                                               size_t nlimit,
 699                                               loff_t start, loff_t end)
 700 {
 701         struct address_space *mapping = inode->i_mapping;
 702         struct folio_batch fbatch;
 703         pgoff_t index = 0, last = ULONG_MAX;
 704         size_t ndirties = 0;
 705         int i;
 706
 707         if (unlikely(start != 0 || end != LLONG_MAX)) {
 708                 /*
 709                  * A valid range is given for sync-ing data pages. The
 710                  * range is rounded to per-page; extra dirty buffers
 711                  * may be included if blocksize < pagesize.
 712                  */
 713                 index = start >> PAGE_SHIFT;
 714                 last = end >> PAGE_SHIFT;
 715         }
 716         folio_batch_init(&fbatch);
 717  repeat:
 718         if (unlikely(index > last) ||
 719               !filemap_get_folios_tag(mapping, &index, last,
 720                       PAGECACHE_TAG_DIRTY, &fbatch))
 721                 return ndirties;
 722
 723         for (i = 0; i < folio_batch_count(&fbatch); i++) {
 724                 struct buffer_head *bh, *head;
 725                 struct folio *folio = fbatch.folios[i];
 726
 727                 folio_lock(folio);
 728                 if (unlikely(folio->mapping != mapping)) {
 729                         /* Exclude folios removed from the address space */
 730                         folio_unlock(folio);
 731                         continue;
 732                 }
 733                 head = folio_buffers(folio);
 734                 if (!head)
 735                         head = create_empty_buffers(folio,
 736                                         i_blocksize(inode), 0);
 737                 folio_unlock(folio);
 738
 739                 bh = head;
 740                 do {
 741                         if (!buffer_dirty(bh) || buffer_async_write(bh))
 742                                 continue;
 743                         get_bh(bh);
 744                         list_add_tail(&bh->b_assoc_buffers, listp);
 745                         ndirties++;
 746                         if (unlikely(ndirties >= nlimit)) {
 747                                 folio_batch_release(&fbatch);
 748                                 cond_resched();
 749                                 return ndirties;
 750                         }
 751                 } while (bh = bh->b_this_page, bh != head);
 752         }
 753         folio_batch_release(&fbatch);
 754         cond_resched();
 755         goto repeat;
 756 }
 757
 758 static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
 759                                             struct list_head *listp)
 760 {
 761         struct nilfs_inode_info *ii = NILFS_I(inode);
 762         struct inode *btnc_inode = ii->i_assoc_inode;
 763         struct folio_batch fbatch;
 764         struct buffer_head *bh, *head;
 765         unsigned int i;
 766         pgoff_t index = 0;
 767
 768         if (!btnc_inode)
 769                 return;
 770         folio_batch_init(&fbatch);
 771
 772         while (filemap_get_folios_tag(btnc_inode->i_mapping, &index,
 773                                 (pgoff_t)-1, PAGECACHE_TAG_DIRTY, &fbatch)) {
 774                 for (i = 0; i < folio_batch_count(&fbatch); i++) {
 775                         bh = head = folio_buffers(fbatch.folios[i]);
 776                         do {
 777                                 if (buffer_dirty(bh) &&
 778                                                 !buffer_async_write(bh)) {
 779                                         get_bh(bh);
 780                                         list_add_tail(&bh->b_assoc_buffers,
 781                                                       listp);
 782                                 }
 783                                 bh = bh->b_this_page;
 784                         } while (bh != head);
 785                 }
 786                 folio_batch_release(&fbatch);
 787                 cond_resched();
 788         }
 789 }
 790
 791 static void nilfs_dispose_list(struct the_nilfs *nilfs,
 792                                struct list_head *head, int force)
 793 {
 794         struct nilfs_inode_info *ii, *n;
 795         struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
 796         unsigned int nv = 0;
 797
 798         while (!list_empty(head)) {
 799                 spin_lock(&nilfs->ns_inode_lock);
 800                 list_for_each_entry_safe(ii, n, head, i_dirty) {
 801                         list_del_init(&ii->i_dirty);
 802                         if (force) {
 803                                 if (unlikely(ii->i_bh)) {
 804                                         brelse(ii->i_bh);
 805                                         ii->i_bh = NULL;
 806                                 }
 807                         } else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
 808                                 set_bit(NILFS_I_QUEUED, &ii->i_state);
 809                                 list_add_tail(&ii->i_dirty,
 810                                               &nilfs->ns_dirty_files);
 811                                 continue;
 812                         }
 813                         ivec[nv++] = ii;
 814                         if (nv == SC_N_INODEVEC)
 815                                 break;
 816                 }
 817                 spin_unlock(&nilfs->ns_inode_lock);
 818
 819                 for (pii = ivec; nv > 0; pii++, nv--)
 820                         iput(&(*pii)->vfs_inode);
 821         }
 822 }
 823
 824 static void nilfs_iput_work_func(struct work_struct *work)
 825 {
 826         struct nilfs_sc_info *sci = container_of(work, struct nilfs_sc_info,
 827                                                  sc_iput_work);
 828         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 829
 830         nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 0);
 831 }
 832
 833 static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
 834                                      struct nilfs_root *root)
 835 {
 836         int ret = 0;
 837
 838         if (nilfs_mdt_fetch_dirty(root->ifile))
 839                 ret++;
 840         if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
 841                 ret++;
 842         if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
 843                 ret++;
 844         if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
 845                 ret++;
 846         return ret;
 847 }
 848
 849 static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 850 {
 851         return list_empty(&sci->sc_dirty_files) &&
 852                 !test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
 853                 sci->sc_nfreesegs == 0 &&
 854                 (!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
 855 }
 856
 857 static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 858 {
 859         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 860         int ret = 0;
 861
 862         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
 863                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
 864
 865         spin_lock(&nilfs->ns_inode_lock);
 866         if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
 867                 ret++;
 868
 869         spin_unlock(&nilfs->ns_inode_lock);
 870         return ret;
 871 }
 872
 873 static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 874 {
 875         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 876
 877         nilfs_mdt_clear_dirty(sci->sc_root->ifile);
 878         nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
 879         nilfs_mdt_clear_dirty(nilfs->ns_sufile);
 880         nilfs_mdt_clear_dirty(nilfs->ns_dat);
 881 }
 882
 883 static void nilfs_fill_in_file_bmap(struct inode *ifile,
 884                                     struct nilfs_inode_info *ii)
 885
 886 {
 887         struct buffer_head *ibh;
 888         struct nilfs_inode *raw_inode;
 889
 890         if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
 891                 ibh = ii->i_bh;
 892                 BUG_ON(!ibh);
 893                 raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
 894                                                   ibh);
 895                 nilfs_bmap_write(ii->i_bmap, raw_inode);
 896                 nilfs_ifile_unmap_inode(raw_inode);
 897         }
 898 }
 899
 900 static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
 901 {
 902         struct nilfs_inode_info *ii;
 903
 904         list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
 905                 nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
 906                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
 907         }
 908 }
 909
 910 /**
 911  * nilfs_write_root_mdt_inode - export root metadata inode information to
 912  *                              the on-disk inode
 913  * @inode:     inode object of the root metadata file
 914  * @raw_inode: on-disk inode
 915  *
 916  * nilfs_write_root_mdt_inode() writes inode information and bmap data of
 917  * @inode to the inode area of the metadata file allocated on the super root
 918  * block created to finalize the log.  Since super root blocks are configured
 919  * each time, this function zero-fills the unused area of @raw_inode.
 920  */
 921 static void nilfs_write_root_mdt_inode(struct inode *inode,
 922                                        struct nilfs_inode *raw_inode)
 923 {
 924         struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
 925
 926         nilfs_write_inode_common(inode, raw_inode);
 927
 928         /* zero-fill unused portion of raw_inode */
 929         raw_inode->i_xattr = 0;
 930         raw_inode->i_pad = 0;
 931         memset((void *)raw_inode + sizeof(*raw_inode), 0,
 932                nilfs->ns_inode_size - sizeof(*raw_inode));
 933
 934         nilfs_bmap_write(NILFS_I(inode)->i_bmap, raw_inode);
 935 }
 936
 937 static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 938                                              struct the_nilfs *nilfs)
 939 {
 940         struct buffer_head *bh_sr;
 941         struct nilfs_super_root *raw_sr;
 942         unsigned int isz, srsz;
 943
 944         bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
 945
 946         lock_buffer(bh_sr);
 947         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 948         isz = nilfs->ns_inode_size;
 949         srsz = NILFS_SR_BYTES(isz);
 950
 951         raw_sr->sr_sum = 0;  /* Ensure initialization within this update */
 952         raw_sr->sr_bytes = cpu_to_le16(srsz);
 953         raw_sr->sr_nongc_ctime
 954                 = cpu_to_le64(nilfs_doing_gc() ?
 955                               nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
 956         raw_sr->sr_flags = 0;
 957
 958         nilfs_write_root_mdt_inode(nilfs->ns_dat, (void *)raw_sr +
 959                                    NILFS_SR_DAT_OFFSET(isz));
 960         nilfs_write_root_mdt_inode(nilfs->ns_cpfile, (void *)raw_sr +
 961                                    NILFS_SR_CPFILE_OFFSET(isz));
 962         nilfs_write_root_mdt_inode(nilfs->ns_sufile, (void *)raw_sr +
 963                                    NILFS_SR_SUFILE_OFFSET(isz));
 964
 965         memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
 966         set_buffer_uptodate(bh_sr);
 967         unlock_buffer(bh_sr);
 968 }
 969
 970 static void nilfs_redirty_inodes(struct list_head *head)
 971 {
 972         struct nilfs_inode_info *ii;
 973
 974         list_for_each_entry(ii, head, i_dirty) {
 975                 if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
 976                         clear_bit(NILFS_I_COLLECTED, &ii->i_state);
 977         }
 978 }
 979
 980 static void nilfs_drop_collected_inodes(struct list_head *head)
 981 {
 982         struct nilfs_inode_info *ii;
 983
 984         list_for_each_entry(ii, head, i_dirty) {
 985                 if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
 986                         continue;
 987
 988                 clear_bit(NILFS_I_INODE_SYNC, &ii->i_state);
 989                 set_bit(NILFS_I_UPDATED, &ii->i_state);
 990         }
 991 }
 992
 993 static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
 994                                        struct inode *inode,
 995                                        struct list_head *listp,
 996                                        int (*collect)(struct nilfs_sc_info *,
 997                                                       struct buffer_head *,
 998                                                       struct inode *))
 999 {
1000         struct buffer_head *bh, *n;
1001         int err = 0;
1002
1003         if (collect) {
1004                 list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
1005                         list_del_init(&bh->b_assoc_buffers);
1006                         err = collect(sci, bh, inode);
1007                         brelse(bh);
1008                         if (unlikely(err))
1009                                 goto dispose_buffers;
1010                 }
1011                 return 0;
1012         }
1013
1014  dispose_buffers:
1015         while (!list_empty(listp)) {
1016                 bh = list_first_entry(listp, struct buffer_head,
1017                                       b_assoc_buffers);
1018                 list_del_init(&bh->b_assoc_buffers);
1019                 brelse(bh);
1020         }
1021         return err;
1022 }
1023
1024 static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
1025 {
1026         /* Remaining number of blocks within segment buffer */
1027         return sci->sc_segbuf_nblocks -
1028                 (sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
1029 }
1030
1031 static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
1032                                    struct inode *inode,
1033                                    const struct nilfs_sc_operations *sc_ops)
1034 {
1035         LIST_HEAD(data_buffers);
1036         LIST_HEAD(node_buffers);
1037         int err;
1038
1039         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1040                 size_t n, rest = nilfs_segctor_buffer_rest(sci);
1041
1042                 n = nilfs_lookup_dirty_data_buffers(
1043                         inode, &data_buffers, rest + 1, 0, LLONG_MAX);
1044                 if (n > rest) {
1045                         err = nilfs_segctor_apply_buffers(
1046                                 sci, inode, &data_buffers,
1047                                 sc_ops->collect_data);
1048                         BUG_ON(!err); /* always receive -E2BIG or true error */
1049                         goto break_or_fail;
1050                 }
1051         }
1052         nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
1053
1054         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1055                 err = nilfs_segctor_apply_buffers(
1056                         sci, inode, &data_buffers, sc_ops->collect_data);
1057                 if (unlikely(err)) {
1058                         /* dispose node list */
1059                         nilfs_segctor_apply_buffers(
1060                                 sci, inode, &node_buffers, NULL);
1061                         goto break_or_fail;
1062                 }
1063                 sci->sc_stage.flags |= NILFS_CF_NODE;
1064         }
1065         /* Collect node */
1066         err = nilfs_segctor_apply_buffers(
1067                 sci, inode, &node_buffers, sc_ops->collect_node);
1068         if (unlikely(err))
1069                 goto break_or_fail;
1070
1071         nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1072         err = nilfs_segctor_apply_buffers(
1073                 sci, inode, &node_buffers, sc_ops->collect_bmap);
1074         if (unlikely(err))
1075                 goto break_or_fail;
1076
1077         nilfs_segctor_end_finfo(sci, inode);
1078         sci->sc_stage.flags &= ~NILFS_CF_NODE;
1079
1080  break_or_fail:
1081         return err;
1082 }
1083
1084 static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1085                                          struct inode *inode)
1086 {
1087         LIST_HEAD(data_buffers);
1088         size_t n, rest = nilfs_segctor_buffer_rest(sci);
1089         int err;
1090
1091         n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1092                                             sci->sc_dsync_start,
1093                                             sci->sc_dsync_end);
1094
1095         err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1096                                           nilfs_collect_file_data);
1097         if (!err) {
1098                 nilfs_segctor_end_finfo(sci, inode);
1099                 BUG_ON(n > rest);
1100                 /* always receive -E2BIG or true error if n > rest */
1101         }
1102         return err;
1103 }
1104
1105 static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1106 {
1107         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1108         struct list_head *head;
1109         struct nilfs_inode_info *ii;
1110         size_t ndone;
1111         int err = 0;
1112
1113         switch (nilfs_sc_cstage_get(sci)) {
1114         case NILFS_ST_INIT:
1115                 /* Pre-processes */
1116                 sci->sc_stage.flags = 0;
1117
1118                 if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1119                         sci->sc_nblk_inc = 0;
1120                         sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1121                         if (mode == SC_LSEG_DSYNC) {
1122                                 nilfs_sc_cstage_set(sci, NILFS_ST_DSYNC);
1123                                 goto dsync_mode;
1124                         }
1125                 }
1126
1127                 sci->sc_stage.dirty_file_ptr = NULL;
1128                 sci->sc_stage.gc_inode_ptr = NULL;
1129                 if (mode == SC_FLUSH_DAT) {
1130                         nilfs_sc_cstage_set(sci, NILFS_ST_DAT);
1131                         goto dat_stage;
1132                 }
1133                 nilfs_sc_cstage_inc(sci);
1134                 fallthrough;
1135         case NILFS_ST_GC:
1136                 if (nilfs_doing_gc()) {
1137                         head = &sci->sc_gc_inodes;
1138                         ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1139                                                 head, i_dirty);
1140                         list_for_each_entry_continue(ii, head, i_dirty) {
1141                                 err = nilfs_segctor_scan_file(
1142                                         sci, &ii->vfs_inode,
1143                                         &nilfs_sc_file_ops);
1144                                 if (unlikely(err)) {
1145                                         sci->sc_stage.gc_inode_ptr = list_entry(
1146                                                 ii->i_dirty.prev,
1147                                                 struct nilfs_inode_info,
1148                                                 i_dirty);
1149                                         goto break_or_fail;
1150                                 }
1151                                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
1152                         }
1153                         sci->sc_stage.gc_inode_ptr = NULL;
1154                 }
1155                 nilfs_sc_cstage_inc(sci);
1156                 fallthrough;
1157         case NILFS_ST_FILE:
1158                 head = &sci->sc_dirty_files;
1159                 ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1160                                         i_dirty);
1161                 list_for_each_entry_continue(ii, head, i_dirty) {
1162                         clear_bit(NILFS_I_DIRTY, &ii->i_state);
1163
1164                         err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1165                                                       &nilfs_sc_file_ops);
1166                         if (unlikely(err)) {
1167                                 sci->sc_stage.dirty_file_ptr =
1168                                         list_entry(ii->i_dirty.prev,
1169                                                    struct nilfs_inode_info,
1170                                                    i_dirty);
1171                                 goto break_or_fail;
1172                         }
1173                         /* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1174                         /* XXX: required ? */
1175                 }
1176                 sci->sc_stage.dirty_file_ptr = NULL;
1177                 if (mode == SC_FLUSH_FILE) {
1178                         nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1179                         return 0;
1180                 }
1181                 nilfs_sc_cstage_inc(sci);
1182                 sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1183                 fallthrough;
1184         case NILFS_ST_IFILE:
1185                 err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1186                                               &nilfs_sc_file_ops);
1187                 if (unlikely(err))
1188                         break;
1189                 nilfs_sc_cstage_inc(sci);
1190                 /* Creating a checkpoint */
1191                 err = nilfs_cpfile_create_checkpoint(nilfs->ns_cpfile,
1192                                                      nilfs->ns_cno);
1193                 if (unlikely(err))
1194                         break;
1195                 fallthrough;
1196         case NILFS_ST_CPFILE:
1197                 err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1198                                               &nilfs_sc_file_ops);
1199                 if (unlikely(err))
1200                         break;
1201                 nilfs_sc_cstage_inc(sci);
1202                 fallthrough;
1203         case NILFS_ST_SUFILE:
1204                 err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1205                                          sci->sc_nfreesegs, &ndone);
1206                 if (unlikely(err)) {
1207                         nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1208                                                   sci->sc_freesegs, ndone,
1209                                                   NULL);
1210                         break;
1211                 }
1212                 sci->sc_stage.flags |= NILFS_CF_SUFREED;
1213
1214                 err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1215                                               &nilfs_sc_file_ops);
1216                 if (unlikely(err))
1217                         break;
1218                 nilfs_sc_cstage_inc(sci);
1219                 fallthrough;
1220         case NILFS_ST_DAT:
1221  dat_stage:
1222                 err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1223                                               &nilfs_sc_dat_ops);
1224                 if (unlikely(err))
1225                         break;
1226                 if (mode == SC_FLUSH_DAT) {
1227                         nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1228                         return 0;
1229                 }
1230                 nilfs_sc_cstage_inc(sci);
1231                 fallthrough;
1232         case NILFS_ST_SR:
1233                 if (mode == SC_LSEG_SR) {
1234                         /* Appending a super root */
1235                         err = nilfs_segctor_add_super_root(sci);
1236                         if (unlikely(err))
1237                                 break;
1238                 }
1239                 /* End of a logical segment */
1240                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1241                 nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1242                 return 0;
1243         case NILFS_ST_DSYNC:
1244  dsync_mode:
1245                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1246                 ii = sci->sc_dsync_inode;
1247                 if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1248                         break;
1249
1250                 err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1251                 if (unlikely(err))
1252                         break;
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_DONE:
1257                 return 0;
1258         default:
1259                 BUG();
1260         }
1261
1262  break_or_fail:
1263         return err;
1264 }
1265
1266 /**
1267  * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1268  * @sci: nilfs_sc_info
1269  * @nilfs: nilfs object
1270  */
1271 static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1272                                             struct the_nilfs *nilfs)
1273 {
1274         struct nilfs_segment_buffer *segbuf, *prev;
1275         __u64 nextnum;
1276         int err, alloc = 0;
1277
1278         segbuf = nilfs_segbuf_new(sci->sc_super);
1279         if (unlikely(!segbuf))
1280                 return -ENOMEM;
1281
1282         if (list_empty(&sci->sc_write_logs)) {
1283                 nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1284                                  nilfs->ns_pseg_offset, nilfs);
1285                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1286                         nilfs_shift_to_next_segment(nilfs);
1287                         nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1288                 }
1289
1290                 segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1291                 nextnum = nilfs->ns_nextnum;
1292
1293                 if (nilfs->ns_segnum == nilfs->ns_nextnum)
1294                         /* Start from the head of a new full segment */
1295                         alloc++;
1296         } else {
1297                 /* Continue logs */
1298                 prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1299                 nilfs_segbuf_map_cont(segbuf, prev);
1300                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1301                 nextnum = prev->sb_nextnum;
1302
1303                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1304                         nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1305                         segbuf->sb_sum.seg_seq++;
1306                         alloc++;
1307                 }
1308         }
1309
1310         err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1311         if (err)
1312                 goto failed;
1313
1314         if (alloc) {
1315                 err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1316                 if (err)
1317                         goto failed;
1318         }
1319         nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1320
1321         BUG_ON(!list_empty(&sci->sc_segbufs));
1322         list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1323         sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1324         return 0;
1325
1326  failed:
1327         nilfs_segbuf_free(segbuf);
1328         return err;
1329 }
1330
1331 static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1332                                          struct the_nilfs *nilfs, int nadd)
1333 {
1334         struct nilfs_segment_buffer *segbuf, *prev;
1335         struct inode *sufile = nilfs->ns_sufile;
1336         __u64 nextnextnum;
1337         LIST_HEAD(list);
1338         int err, ret, i;
1339
1340         prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1341         /*
1342          * Since the segment specified with nextnum might be allocated during
1343          * the previous construction, the buffer including its segusage may
1344          * not be dirty.  The following call ensures that the buffer is dirty
1345          * and will pin the buffer on memory until the sufile is written.
1346          */
1347         err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1348         if (unlikely(err))
1349                 return err;
1350
1351         for (i = 0; i < nadd; i++) {
1352                 /* extend segment info */
1353                 err = -ENOMEM;
1354                 segbuf = nilfs_segbuf_new(sci->sc_super);
1355                 if (unlikely(!segbuf))
1356                         goto failed;
1357
1358                 /* map this buffer to region of segment on-disk */
1359                 nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1360                 sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1361
1362                 /* allocate the next next full segment */
1363                 err = nilfs_sufile_alloc(sufile, &nextnextnum);
1364                 if (unlikely(err))
1365                         goto failed_segbuf;
1366
1367                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1368                 nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1369
1370                 list_add_tail(&segbuf->sb_list, &list);
1371                 prev = segbuf;
1372         }
1373         list_splice_tail(&list, &sci->sc_segbufs);
1374         return 0;
1375
1376  failed_segbuf:
1377         nilfs_segbuf_free(segbuf);
1378  failed:
1379         list_for_each_entry(segbuf, &list, sb_list) {
1380                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1381                 WARN_ON(ret); /* never fails */
1382         }
1383         nilfs_destroy_logs(&list);
1384         return err;
1385 }
1386
1387 static void nilfs_free_incomplete_logs(struct list_head *logs,
1388                                        struct the_nilfs *nilfs)
1389 {
1390         struct nilfs_segment_buffer *segbuf, *prev;
1391         struct inode *sufile = nilfs->ns_sufile;
1392         int ret;
1393
1394         segbuf = NILFS_FIRST_SEGBUF(logs);
1395         if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1396                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1397                 WARN_ON(ret); /* never fails */
1398         }
1399         if (atomic_read(&segbuf->sb_err)) {
1400                 /* Case 1: The first segment failed */
1401                 if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1402                         /*
1403                          * Case 1a:  Partial segment appended into an existing
1404                          * segment
1405                          */
1406                         nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1407                                                 segbuf->sb_fseg_end);
1408                 else /* Case 1b:  New full segment */
1409                         set_nilfs_discontinued(nilfs);
1410         }
1411
1412         prev = segbuf;
1413         list_for_each_entry_continue(segbuf, logs, sb_list) {
1414                 if (prev->sb_nextnum != segbuf->sb_nextnum) {
1415                         ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1416                         WARN_ON(ret); /* never fails */
1417                 }
1418                 if (atomic_read(&segbuf->sb_err) &&
1419                     segbuf->sb_segnum != nilfs->ns_nextnum)
1420                         /* Case 2: extended segment (!= next) failed */
1421                         nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1422                 prev = segbuf;
1423         }
1424 }
1425
1426 static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1427                                           struct inode *sufile)
1428 {
1429         struct nilfs_segment_buffer *segbuf;
1430         unsigned long live_blocks;
1431         int ret;
1432
1433         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1434                 live_blocks = segbuf->sb_sum.nblocks +
1435                         (segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1436                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1437                                                      live_blocks,
1438                                                      sci->sc_seg_ctime);
1439                 WARN_ON(ret); /* always succeed because the segusage is dirty */
1440         }
1441 }
1442
1443 static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1444 {
1445         struct nilfs_segment_buffer *segbuf;
1446         int ret;
1447
1448         segbuf = NILFS_FIRST_SEGBUF(logs);
1449         ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1450                                              segbuf->sb_pseg_start -
1451                                              segbuf->sb_fseg_start, 0);
1452         WARN_ON(ret); /* always succeed because the segusage is dirty */
1453
1454         list_for_each_entry_continue(segbuf, logs, sb_list) {
1455                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1456                                                      0, 0);
1457                 WARN_ON(ret); /* always succeed */
1458         }
1459 }
1460
1461 static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1462                                             struct nilfs_segment_buffer *last,
1463                                             struct inode *sufile)
1464 {
1465         struct nilfs_segment_buffer *segbuf = last;
1466         int ret;
1467
1468         list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1469                 sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1470                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1471                 WARN_ON(ret);
1472         }
1473         nilfs_truncate_logs(&sci->sc_segbufs, last);
1474 }
1475
1476
1477 static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1478                                  struct the_nilfs *nilfs, int mode)
1479 {
1480         struct nilfs_cstage prev_stage = sci->sc_stage;
1481         int err, nadd = 1;
1482
1483         /* Collection retry loop */
1484         for (;;) {
1485                 sci->sc_nblk_this_inc = 0;
1486                 sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1487
1488                 err = nilfs_segctor_reset_segment_buffer(sci);
1489                 if (unlikely(err))
1490                         goto failed;
1491
1492                 err = nilfs_segctor_collect_blocks(sci, mode);
1493                 sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1494                 if (!err)
1495                         break;
1496
1497                 if (unlikely(err != -E2BIG))
1498                         goto failed;
1499
1500                 /* The current segment is filled up */
1501                 if (mode != SC_LSEG_SR ||
1502                     nilfs_sc_cstage_get(sci) < NILFS_ST_CPFILE)
1503                         break;
1504
1505                 nilfs_clear_logs(&sci->sc_segbufs);
1506
1507                 if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1508                         err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1509                                                         sci->sc_freesegs,
1510                                                         sci->sc_nfreesegs,
1511                                                         NULL);
1512                         WARN_ON(err); /* do not happen */
1513                         sci->sc_stage.flags &= ~NILFS_CF_SUFREED;
1514                 }
1515
1516                 err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1517                 if (unlikely(err))
1518                         return err;
1519
1520                 nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1521                 sci->sc_stage = prev_stage;
1522         }
1523         nilfs_segctor_zeropad_segsum(sci);
1524         nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1525         return 0;
1526
1527  failed:
1528         return err;
1529 }
1530
1531 static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1532                                       struct buffer_head *new_bh)
1533 {
1534         BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1535
1536         list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1537         /* The caller must release old_bh */
1538 }
1539
1540 static int
1541 nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1542                                      struct nilfs_segment_buffer *segbuf,
1543                                      int mode)
1544 {
1545         struct inode *inode = NULL;
1546         sector_t blocknr;
1547         unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1548         unsigned long nblocks = 0, ndatablk = 0;
1549         const struct nilfs_sc_operations *sc_op = NULL;
1550         struct nilfs_segsum_pointer ssp;
1551         struct nilfs_finfo *finfo = NULL;
1552         union nilfs_binfo binfo;
1553         struct buffer_head *bh, *bh_org;
1554         ino_t ino = 0;
1555         int err = 0;
1556
1557         if (!nfinfo)
1558                 goto out;
1559
1560         blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1561         ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1562         ssp.offset = sizeof(struct nilfs_segment_summary);
1563
1564         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1565                 if (bh == segbuf->sb_super_root)
1566                         break;
1567                 if (!finfo) {
1568                         finfo = nilfs_segctor_map_segsum_entry(
1569                                 sci, &ssp, sizeof(*finfo));
1570                         ino = le64_to_cpu(finfo->fi_ino);
1571                         nblocks = le32_to_cpu(finfo->fi_nblocks);
1572                         ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1573
1574                         inode = bh->b_folio->mapping->host;
1575
1576                         if (mode == SC_LSEG_DSYNC)
1577                                 sc_op = &nilfs_sc_dsync_ops;
1578                         else if (ino == NILFS_DAT_INO)
1579                                 sc_op = &nilfs_sc_dat_ops;
1580                         else /* file blocks */
1581                                 sc_op = &nilfs_sc_file_ops;
1582                 }
1583                 bh_org = bh;
1584                 get_bh(bh_org);
1585                 err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1586                                         &binfo);
1587                 if (bh != bh_org)
1588                         nilfs_list_replace_buffer(bh_org, bh);
1589                 brelse(bh_org);
1590                 if (unlikely(err))
1591                         goto failed_bmap;
1592
1593                 if (ndatablk > 0)
1594                         sc_op->write_data_binfo(sci, &ssp, &binfo);
1595                 else
1596                         sc_op->write_node_binfo(sci, &ssp, &binfo);
1597
1598                 blocknr++;
1599                 if (--nblocks == 0) {
1600                         finfo = NULL;
1601                         if (--nfinfo == 0)
1602                                 break;
1603                 } else if (ndatablk > 0)
1604                         ndatablk--;
1605         }
1606  out:
1607         return 0;
1608
1609  failed_bmap:
1610         return err;
1611 }
1612
1613 static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1614 {
1615         struct nilfs_segment_buffer *segbuf;
1616         int err;
1617
1618         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1619                 err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1620                 if (unlikely(err))
1621                         return err;
1622                 nilfs_segbuf_fill_in_segsum(segbuf);
1623         }
1624         return 0;
1625 }
1626
1627 static void nilfs_begin_folio_io(struct folio *folio)
1628 {
1629         if (!folio || folio_test_writeback(folio))
1630                 /*
1631                  * For split b-tree node pages, this function may be called
1632                  * twice.  We ignore the 2nd or later calls by this check.
1633                  */
1634                 return;
1635
1636         folio_lock(folio);
1637         folio_clear_dirty_for_io(folio);
1638         folio_start_writeback(folio);
1639         folio_unlock(folio);
1640 }
1641
1642 static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci)
1643 {
1644         struct nilfs_segment_buffer *segbuf;
1645         struct folio *bd_folio = NULL, *fs_folio = NULL;
1646
1647         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1648                 struct buffer_head *bh;
1649
1650                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1651                                     b_assoc_buffers) {
1652                         if (bh->b_folio != bd_folio) {
1653                                 if (bd_folio) {
1654                                         folio_lock(bd_folio);
1655                                         folio_clear_dirty_for_io(bd_folio);
1656                                         folio_start_writeback(bd_folio);
1657                                         folio_unlock(bd_folio);
1658                                 }
1659                                 bd_folio = bh->b_folio;
1660                         }
1661                 }
1662
1663                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1664                                     b_assoc_buffers) {
1665                         if (bh == segbuf->sb_super_root) {
1666                                 if (bh->b_folio != bd_folio) {
1667                                         folio_lock(bd_folio);
1668                                         folio_clear_dirty_for_io(bd_folio);
1669                                         folio_start_writeback(bd_folio);
1670                                         folio_unlock(bd_folio);
1671                                         bd_folio = bh->b_folio;
1672                                 }
1673                                 break;
1674                         }
1675                         set_buffer_async_write(bh);
1676                         if (bh->b_folio != fs_folio) {
1677                                 nilfs_begin_folio_io(fs_folio);
1678                                 fs_folio = bh->b_folio;
1679                         }
1680                 }
1681         }
1682         if (bd_folio) {
1683                 folio_lock(bd_folio);
1684                 folio_clear_dirty_for_io(bd_folio);
1685                 folio_start_writeback(bd_folio);
1686                 folio_unlock(bd_folio);
1687         }
1688         nilfs_begin_folio_io(fs_folio);
1689 }
1690
1691 static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1692                                struct the_nilfs *nilfs)
1693 {
1694         int ret;
1695
1696         ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1697         list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1698         return ret;
1699 }
1700
1701 static void nilfs_end_folio_io(struct folio *folio, int err)
1702 {
1703         if (!folio)
1704                 return;
1705
1706         if (buffer_nilfs_node(folio_buffers(folio)) &&
1707                         !folio_test_writeback(folio)) {
1708                 /*
1709                  * For b-tree node pages, this function may be called twice
1710                  * or more because they might be split in a segment.
1711                  */
1712                 if (folio_test_dirty(folio)) {
1713                         /*
1714                          * For pages holding split b-tree node buffers, dirty
1715                          * flag on the buffers may be cleared discretely.
1716                          * In that case, the page is once redirtied for
1717                          * remaining buffers, and it must be cancelled if
1718                          * all the buffers get cleaned later.
1719                          */
1720                         folio_lock(folio);
1721                         if (nilfs_folio_buffers_clean(folio))
1722                                 __nilfs_clear_folio_dirty(folio);
1723                         folio_unlock(folio);
1724                 }
1725                 return;
1726         }
1727
1728         if (err || !nilfs_folio_buffers_clean(folio))
1729                 filemap_dirty_folio(folio->mapping, folio);
1730
1731         folio_end_writeback(folio);
1732 }
1733
1734 static void nilfs_abort_logs(struct list_head *logs, int err)
1735 {
1736         struct nilfs_segment_buffer *segbuf;
1737         struct folio *bd_folio = NULL, *fs_folio = NULL;
1738         struct buffer_head *bh;
1739
1740         if (list_empty(logs))
1741                 return;
1742
1743         list_for_each_entry(segbuf, logs, sb_list) {
1744                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1745                                     b_assoc_buffers) {
1746                         clear_buffer_uptodate(bh);
1747                         if (bh->b_folio != bd_folio) {
1748                                 if (bd_folio)
1749                                         folio_end_writeback(bd_folio);
1750                                 bd_folio = bh->b_folio;
1751                         }
1752                 }
1753
1754                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1755                                     b_assoc_buffers) {
1756                         if (bh == segbuf->sb_super_root) {
1757                                 clear_buffer_uptodate(bh);
1758                                 if (bh->b_folio != bd_folio) {
1759                                         folio_end_writeback(bd_folio);
1760                                         bd_folio = bh->b_folio;
1761                                 }
1762                                 break;
1763                         }
1764                         clear_buffer_async_write(bh);
1765                         if (bh->b_folio != fs_folio) {
1766                                 nilfs_end_folio_io(fs_folio, err);
1767                                 fs_folio = bh->b_folio;
1768                         }
1769                 }
1770         }
1771         if (bd_folio)
1772                 folio_end_writeback(bd_folio);
1773
1774         nilfs_end_folio_io(fs_folio, err);
1775 }
1776
1777 static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
1778                                              struct the_nilfs *nilfs, int err)
1779 {
1780         LIST_HEAD(logs);
1781         int ret;
1782
1783         list_splice_tail_init(&sci->sc_write_logs, &logs);
1784         ret = nilfs_wait_on_logs(&logs);
1785         nilfs_abort_logs(&logs, ret ? : err);
1786
1787         list_splice_tail_init(&sci->sc_segbufs, &logs);
1788         nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
1789         nilfs_free_incomplete_logs(&logs, nilfs);
1790
1791         if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1792                 ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1793                                                 sci->sc_freesegs,
1794                                                 sci->sc_nfreesegs,
1795                                                 NULL);
1796                 WARN_ON(ret); /* do not happen */
1797         }
1798
1799         nilfs_destroy_logs(&logs);
1800 }
1801
1802 static void nilfs_set_next_segment(struct the_nilfs *nilfs,
1803                                    struct nilfs_segment_buffer *segbuf)
1804 {
1805         nilfs->ns_segnum = segbuf->sb_segnum;
1806         nilfs->ns_nextnum = segbuf->sb_nextnum;
1807         nilfs->ns_pseg_offset = segbuf->sb_pseg_start - segbuf->sb_fseg_start
1808                 + segbuf->sb_sum.nblocks;
1809         nilfs->ns_seg_seq = segbuf->sb_sum.seg_seq;
1810         nilfs->ns_ctime = segbuf->sb_sum.ctime;
1811 }
1812
1813 static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
1814 {
1815         struct nilfs_segment_buffer *segbuf;
1816         struct folio *bd_folio = NULL, *fs_folio = NULL;
1817         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1818         int update_sr = false;
1819
1820         list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
1821                 struct buffer_head *bh;
1822
1823                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1824                                     b_assoc_buffers) {
1825                         set_buffer_uptodate(bh);
1826                         clear_buffer_dirty(bh);
1827                         if (bh->b_folio != bd_folio) {
1828                                 if (bd_folio)
1829                                         folio_end_writeback(bd_folio);
1830                                 bd_folio = bh->b_folio;
1831                         }
1832                 }
1833                 /*
1834                  * We assume that the buffers which belong to the same folio
1835                  * continue over the buffer list.
1836                  * Under this assumption, the last BHs of folios is
1837                  * identifiable by the discontinuity of bh->b_folio
1838                  * (folio != fs_folio).
1839                  *
1840                  * For B-tree node blocks, however, this assumption is not
1841                  * guaranteed.  The cleanup code of B-tree node folios needs
1842                  * special care.
1843                  */
1844                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1845                                     b_assoc_buffers) {
1846                         const unsigned long set_bits = BIT(BH_Uptodate);
1847                         const unsigned long clear_bits =
1848                                 (BIT(BH_Dirty) | BIT(BH_Async_Write) |
1849                                  BIT(BH_Delay) | BIT(BH_NILFS_Volatile) |
1850                                  BIT(BH_NILFS_Redirected));
1851
1852                         if (bh == segbuf->sb_super_root) {
1853                                 set_buffer_uptodate(bh);
1854                                 clear_buffer_dirty(bh);
1855                                 if (bh->b_folio != bd_folio) {
1856                                         folio_end_writeback(bd_folio);
1857                                         bd_folio = bh->b_folio;
1858                                 }
1859                                 update_sr = true;
1860                                 break;
1861                         }
1862                         set_mask_bits(&bh->b_state, clear_bits, set_bits);
1863                         if (bh->b_folio != fs_folio) {
1864                                 nilfs_end_folio_io(fs_folio, 0);
1865                                 fs_folio = bh->b_folio;
1866                         }
1867                 }
1868
1869                 if (!nilfs_segbuf_simplex(segbuf)) {
1870                         if (segbuf->sb_sum.flags & NILFS_SS_LOGBGN) {
1871                                 set_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1872                                 sci->sc_lseg_stime = jiffies;
1873                         }
1874                         if (segbuf->sb_sum.flags & NILFS_SS_LOGEND)
1875                                 clear_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1876                 }
1877         }
1878         /*
1879          * Since folios may continue over multiple segment buffers,
1880          * end of the last folio must be checked outside of the loop.
1881          */
1882         if (bd_folio)
1883                 folio_end_writeback(bd_folio);
1884
1885         nilfs_end_folio_io(fs_folio, 0);
1886
1887         nilfs_drop_collected_inodes(&sci->sc_dirty_files);
1888
1889         if (nilfs_doing_gc())
1890                 nilfs_drop_collected_inodes(&sci->sc_gc_inodes);
1891         else
1892                 nilfs->ns_nongc_ctime = sci->sc_seg_ctime;
1893
1894         sci->sc_nblk_inc += sci->sc_nblk_this_inc;
1895
1896         segbuf = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1897         nilfs_set_next_segment(nilfs, segbuf);
1898
1899         if (update_sr) {
1900                 nilfs->ns_flushed_device = 0;
1901                 nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
1902                                        segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
1903
1904                 clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
1905                 clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1906                 set_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1907                 nilfs_segctor_clear_metadata_dirty(sci);
1908         } else
1909                 clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1910 }
1911
1912 static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
1913 {
1914         int ret;
1915
1916         ret = nilfs_wait_on_logs(&sci->sc_write_logs);
1917         if (!ret) {
1918                 nilfs_segctor_complete_write(sci);
1919                 nilfs_destroy_logs(&sci->sc_write_logs);
1920         }
1921         return ret;
1922 }
1923
1924 static int nilfs_segctor_collect_dirty_files(struct nilfs_sc_info *sci,
1925                                              struct the_nilfs *nilfs)
1926 {
1927         struct nilfs_inode_info *ii, *n;
1928         struct inode *ifile = sci->sc_root->ifile;
1929
1930         spin_lock(&nilfs->ns_inode_lock);
1931  retry:
1932         list_for_each_entry_safe(ii, n, &nilfs->ns_dirty_files, i_dirty) {
1933                 if (!ii->i_bh) {
1934                         struct buffer_head *ibh;
1935                         int err;
1936
1937                         spin_unlock(&nilfs->ns_inode_lock);
1938                         err = nilfs_ifile_get_inode_block(
1939                                 ifile, ii->vfs_inode.i_ino, &ibh);
1940                         if (unlikely(err)) {
1941                                 nilfs_warn(sci->sc_super,
1942                                            "log writer: error %d getting inode block (ino=%lu)",
1943                                            err, ii->vfs_inode.i_ino);
1944                                 return err;
1945                         }
1946                         spin_lock(&nilfs->ns_inode_lock);
1947                         if (likely(!ii->i_bh))
1948                                 ii->i_bh = ibh;
1949                         else
1950                                 brelse(ibh);
1951                         goto retry;
1952                 }
1953
1954                 // Always redirty the buffer to avoid race condition
1955                 mark_buffer_dirty(ii->i_bh);
1956                 nilfs_mdt_mark_dirty(ifile);
1957
1958                 clear_bit(NILFS_I_QUEUED, &ii->i_state);
1959                 set_bit(NILFS_I_BUSY, &ii->i_state);
1960                 list_move_tail(&ii->i_dirty, &sci->sc_dirty_files);
1961         }
1962         spin_unlock(&nilfs->ns_inode_lock);
1963
1964         return 0;
1965 }
1966
1967 static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
1968                                              struct the_nilfs *nilfs)
1969 {
1970         struct nilfs_inode_info *ii, *n;
1971         int during_mount = !(sci->sc_super->s_flags & SB_ACTIVE);
1972         int defer_iput = false;
1973
1974         spin_lock(&nilfs->ns_inode_lock);
1975         list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
1976                 if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
1977                     test_bit(NILFS_I_DIRTY, &ii->i_state))
1978                         continue;
1979
1980                 clear_bit(NILFS_I_BUSY, &ii->i_state);
1981                 brelse(ii->i_bh);
1982                 ii->i_bh = NULL;
1983                 list_del_init(&ii->i_dirty);
1984                 if (!ii->vfs_inode.i_nlink || during_mount) {
1985                         /*
1986                          * Defer calling iput() to avoid deadlocks if
1987                          * i_nlink == 0 or mount is not yet finished.
1988                          */
1989                         list_add_tail(&ii->i_dirty, &sci->sc_iput_queue);
1990                         defer_iput = true;
1991                 } else {
1992                         spin_unlock(&nilfs->ns_inode_lock);
1993                         iput(&ii->vfs_inode);
1994                         spin_lock(&nilfs->ns_inode_lock);
1995                 }
1996         }
1997         spin_unlock(&nilfs->ns_inode_lock);
1998
1999         if (defer_iput)
2000                 schedule_work(&sci->sc_iput_work);
2001 }
2002
2003 /*
2004  * Main procedure of segment constructor
2005  */
2006 static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
2007 {
2008         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2009         int err;
2010
2011         if (sb_rdonly(sci->sc_super))
2012                 return -EROFS;
2013
2014         nilfs_sc_cstage_set(sci, NILFS_ST_INIT);
2015         sci->sc_cno = nilfs->ns_cno;
2016
2017         err = nilfs_segctor_collect_dirty_files(sci, nilfs);
2018         if (unlikely(err))
2019                 goto out;
2020
2021         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
2022                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
2023
2024         if (nilfs_segctor_clean(sci))
2025                 goto out;
2026
2027         do {
2028                 sci->sc_stage.flags &= ~NILFS_CF_HISTORY_MASK;
2029
2030                 err = nilfs_segctor_begin_construction(sci, nilfs);
2031                 if (unlikely(err))
2032                         goto out;
2033
2034                 /* Update time stamp */
2035                 sci->sc_seg_ctime = ktime_get_real_seconds();
2036
2037                 err = nilfs_segctor_collect(sci, nilfs, mode);
2038                 if (unlikely(err))
2039                         goto failed;
2040
2041                 /* Avoid empty segment */
2042                 if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE &&
2043                     nilfs_segbuf_empty(sci->sc_curseg)) {
2044                         nilfs_segctor_abort_construction(sci, nilfs, 1);
2045                         goto out;
2046                 }
2047
2048                 err = nilfs_segctor_assign(sci, mode);
2049                 if (unlikely(err))
2050                         goto failed;
2051
2052                 if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2053                         nilfs_segctor_fill_in_file_bmap(sci);
2054
2055                 if (mode == SC_LSEG_SR &&
2056                     nilfs_sc_cstage_get(sci) >= NILFS_ST_CPFILE) {
2057                         err = nilfs_cpfile_finalize_checkpoint(
2058                                 nilfs->ns_cpfile, nilfs->ns_cno, sci->sc_root,
2059                                 sci->sc_nblk_inc + sci->sc_nblk_this_inc,
2060                                 sci->sc_seg_ctime,
2061                                 !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags));
2062                         if (unlikely(err))
2063                                 goto failed_to_write;
2064
2065                         nilfs_segctor_fill_in_super_root(sci, nilfs);
2066                 }
2067                 nilfs_segctor_update_segusage(sci, nilfs->ns_sufile);
2068
2069                 /* Write partial segments */
2070                 nilfs_segctor_prepare_write(sci);
2071
2072                 nilfs_add_checksums_on_logs(&sci->sc_segbufs,
2073                                             nilfs->ns_crc_seed);
2074
2075                 err = nilfs_segctor_write(sci, nilfs);
2076                 if (unlikely(err))
2077                         goto failed_to_write;
2078
2079                 if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE ||
2080                     nilfs->ns_blocksize_bits != PAGE_SHIFT) {
2081                         /*
2082                          * At this point, we avoid double buffering
2083                          * for blocksize < pagesize because page dirty
2084                          * flag is turned off during write and dirty
2085                          * buffers are not properly collected for
2086                          * pages crossing over segments.
2087                          */
2088                         err = nilfs_segctor_wait(sci);
2089                         if (err)
2090                                 goto failed_to_write;
2091                 }
2092         } while (nilfs_sc_cstage_get(sci) != NILFS_ST_DONE);
2093
2094  out:
2095         nilfs_segctor_drop_written_files(sci, nilfs);
2096         return err;
2097
2098  failed_to_write:
2099         if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2100                 nilfs_redirty_inodes(&sci->sc_dirty_files);
2101
2102  failed:
2103         if (nilfs_doing_gc())
2104                 nilfs_redirty_inodes(&sci->sc_gc_inodes);
2105         nilfs_segctor_abort_construction(sci, nilfs, err);
2106         goto out;
2107 }
2108
2109 /**
2110  * nilfs_segctor_start_timer - set timer of background write
2111  * @sci: nilfs_sc_info
2112  *
2113  * If the timer has already been set, it ignores the new request.
2114  * This function MUST be called within a section locking the segment
2115  * semaphore.
2116  */
2117 static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
2118 {
2119         spin_lock(&sci->sc_state_lock);
2120         if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
2121                 sci->sc_timer.expires = jiffies + sci->sc_interval;
2122                 add_timer(&sci->sc_timer);
2123                 sci->sc_state |= NILFS_SEGCTOR_COMMIT;
2124         }
2125         spin_unlock(&sci->sc_state_lock);
2126 }
2127
2128 static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
2129 {
2130         spin_lock(&sci->sc_state_lock);
2131         if (!(sci->sc_flush_request & BIT(bn))) {
2132                 unsigned long prev_req = sci->sc_flush_request;
2133
2134                 sci->sc_flush_request |= BIT(bn);
2135                 if (!prev_req)
2136                         wake_up(&sci->sc_wait_daemon);
2137         }
2138         spin_unlock(&sci->sc_state_lock);
2139 }
2140
2141 /**
2142  * nilfs_flush_segment - trigger a segment construction for resource control
2143  * @sb: super block
2144  * @ino: inode number of the file to be flushed out.
2145  */
2146 void nilfs_flush_segment(struct super_block *sb, ino_t ino)
2147 {
2148         struct the_nilfs *nilfs = sb->s_fs_info;
2149         struct nilfs_sc_info *sci = nilfs->ns_writer;
2150
2151         if (!sci || nilfs_doing_construction())
2152                 return;
2153         nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
2154                                         /* assign bit 0 to data files */
2155 }
2156
2157 struct nilfs_segctor_wait_request {
2158         wait_queue_entry_t      wq;
2159         __u32           seq;
2160         int             err;
2161         atomic_t        done;
2162 };
2163
2164 static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
2165 {
2166         struct nilfs_segctor_wait_request wait_req;
2167         int err = 0;
2168
2169         spin_lock(&sci->sc_state_lock);
2170         init_wait(&wait_req.wq);
2171         wait_req.err = 0;
2172         atomic_set(&wait_req.done, 0);
2173         wait_req.seq = ++sci->sc_seq_request;
2174         spin_unlock(&sci->sc_state_lock);
2175
2176         init_waitqueue_entry(&wait_req.wq, current);
2177         add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
2178         set_current_state(TASK_INTERRUPTIBLE);
2179         wake_up(&sci->sc_wait_daemon);
2180
2181         for (;;) {
2182                 if (atomic_read(&wait_req.done)) {
2183                         err = wait_req.err;
2184                         break;
2185                 }
2186                 if (!signal_pending(current)) {
2187                         schedule();
2188                         continue;
2189                 }
2190                 err = -ERESTARTSYS;
2191                 break;
2192         }
2193         finish_wait(&sci->sc_wait_request, &wait_req.wq);
2194         return err;
2195 }
2196
2197 static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
2198 {
2199         struct nilfs_segctor_wait_request *wrq, *n;
2200         unsigned long flags;
2201
2202         spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
2203         list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.head, wq.entry) {
2204                 if (!atomic_read(&wrq->done) &&
2205                     nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
2206                         wrq->err = err;
2207                         atomic_set(&wrq->done, 1);
2208                 }
2209                 if (atomic_read(&wrq->done)) {
2210                         wrq->wq.func(&wrq->wq,
2211                                      TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
2212                                      0, NULL);
2213                 }
2214         }
2215         spin_unlock_irqrestore(&sci->sc_wait_request.lock, flags);
2216 }
2217
2218 /**
2219  * nilfs_construct_segment - construct a logical segment
2220  * @sb: super block
2221  *
2222  * Return Value: On success, 0 is returned. On errors, one of the following
2223  * negative error code is returned.
2224  *
2225  * %-EROFS - Read only filesystem.
2226  *
2227  * %-EIO - I/O error
2228  *
2229  * %-ENOSPC - No space left on device (only in a panic state).
2230  *
2231  * %-ERESTARTSYS - Interrupted.
2232  *
2233  * %-ENOMEM - Insufficient memory available.
2234  */
2235 int nilfs_construct_segment(struct super_block *sb)
2236 {
2237         struct the_nilfs *nilfs = sb->s_fs_info;
2238         struct nilfs_sc_info *sci = nilfs->ns_writer;
2239         struct nilfs_transaction_info *ti;
2240
2241         if (sb_rdonly(sb) || unlikely(!sci))
2242                 return -EROFS;
2243
2244         /* A call inside transactions causes a deadlock. */
2245         BUG_ON((ti = current->journal_info) && ti->ti_magic == NILFS_TI_MAGIC);
2246
2247         return nilfs_segctor_sync(sci);
2248 }
2249
2250 /**
2251  * nilfs_construct_dsync_segment - construct a data-only logical segment
2252  * @sb: super block
2253  * @inode: inode whose data blocks should be written out
2254  * @start: start byte offset
2255  * @end: end byte offset (inclusive)
2256  *
2257  * Return Value: On success, 0 is returned. On errors, one of the following
2258  * negative error code is returned.
2259  *
2260  * %-EROFS - Read only filesystem.
2261  *
2262  * %-EIO - I/O error
2263  *
2264  * %-ENOSPC - No space left on device (only in a panic state).
2265  *
2266  * %-ERESTARTSYS - Interrupted.
2267  *
2268  * %-ENOMEM - Insufficient memory available.
2269  */
2270 int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
2271                                   loff_t start, loff_t end)
2272 {
2273         struct the_nilfs *nilfs = sb->s_fs_info;
2274         struct nilfs_sc_info *sci = nilfs->ns_writer;
2275         struct nilfs_inode_info *ii;
2276         struct nilfs_transaction_info ti;
2277         int err = 0;
2278
2279         if (sb_rdonly(sb) || unlikely(!sci))
2280                 return -EROFS;
2281
2282         nilfs_transaction_lock(sb, &ti, 0);
2283
2284         ii = NILFS_I(inode);
2285         if (test_bit(NILFS_I_INODE_SYNC, &ii->i_state) ||
2286             nilfs_test_opt(nilfs, STRICT_ORDER) ||
2287             test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2288             nilfs_discontinued(nilfs)) {
2289                 nilfs_transaction_unlock(sb);
2290                 err = nilfs_segctor_sync(sci);
2291                 return err;
2292         }
2293
2294         spin_lock(&nilfs->ns_inode_lock);
2295         if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
2296             !test_bit(NILFS_I_BUSY, &ii->i_state)) {
2297                 spin_unlock(&nilfs->ns_inode_lock);
2298                 nilfs_transaction_unlock(sb);
2299                 return 0;
2300         }
2301         spin_unlock(&nilfs->ns_inode_lock);
2302         sci->sc_dsync_inode = ii;
2303         sci->sc_dsync_start = start;
2304         sci->sc_dsync_end = end;
2305
2306         err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC);
2307         if (!err)
2308                 nilfs->ns_flushed_device = 0;
2309
2310         nilfs_transaction_unlock(sb);
2311         return err;
2312 }
2313
2314 #define FLUSH_FILE_BIT  (0x1) /* data file only */
2315 #define FLUSH_DAT_BIT   BIT(NILFS_DAT_INO) /* DAT only */
2316
2317 /**
2318  * nilfs_segctor_accept - record accepted sequence count of log-write requests
2319  * @sci: segment constructor object
2320  */
2321 static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
2322 {
2323         spin_lock(&sci->sc_state_lock);
2324         sci->sc_seq_accepted = sci->sc_seq_request;
2325         spin_unlock(&sci->sc_state_lock);
2326         del_timer_sync(&sci->sc_timer);
2327 }
2328
2329 /**
2330  * nilfs_segctor_notify - notify the result of request to caller threads
2331  * @sci: segment constructor object
2332  * @mode: mode of log forming
2333  * @err: error code to be notified
2334  */
2335 static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
2336 {
2337         /* Clear requests (even when the construction failed) */
2338         spin_lock(&sci->sc_state_lock);
2339
2340         if (mode == SC_LSEG_SR) {
2341                 sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
2342                 sci->sc_seq_done = sci->sc_seq_accepted;
2343                 nilfs_segctor_wakeup(sci, err);
2344                 sci->sc_flush_request = 0;
2345         } else {
2346                 if (mode == SC_FLUSH_FILE)
2347                         sci->sc_flush_request &= ~FLUSH_FILE_BIT;
2348                 else if (mode == SC_FLUSH_DAT)
2349                         sci->sc_flush_request &= ~FLUSH_DAT_BIT;
2350
2351                 /* re-enable timer if checkpoint creation was not done */
2352                 if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2353                     time_before(jiffies, sci->sc_timer.expires))
2354                         add_timer(&sci->sc_timer);
2355         }
2356         spin_unlock(&sci->sc_state_lock);
2357 }
2358
2359 /**
2360  * nilfs_segctor_construct - form logs and write them to disk
2361  * @sci: segment constructor object
2362  * @mode: mode of log forming
2363  */
2364 static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
2365 {
2366         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2367         struct nilfs_super_block **sbp;
2368         int err = 0;
2369
2370         nilfs_segctor_accept(sci);
2371
2372         if (nilfs_discontinued(nilfs))
2373                 mode = SC_LSEG_SR;
2374         if (!nilfs_segctor_confirm(sci))
2375                 err = nilfs_segctor_do_construct(sci, mode);
2376
2377         if (likely(!err)) {
2378                 if (mode != SC_FLUSH_DAT)
2379                         atomic_set(&nilfs->ns_ndirtyblks, 0);
2380                 if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
2381                     nilfs_discontinued(nilfs)) {
2382                         down_write(&nilfs->ns_sem);
2383                         err = -EIO;
2384                         sbp = nilfs_prepare_super(sci->sc_super,
2385                                                   nilfs_sb_will_flip(nilfs));
2386                         if (likely(sbp)) {
2387                                 nilfs_set_log_cursor(sbp[0], nilfs);
2388                                 err = nilfs_commit_super(sci->sc_super,
2389                                                          NILFS_SB_COMMIT);
2390                         }
2391                         up_write(&nilfs->ns_sem);
2392                 }
2393         }
2394
2395         nilfs_segctor_notify(sci, mode, err);
2396         return err;
2397 }
2398
2399 static void nilfs_construction_timeout(struct timer_list *t)
2400 {
2401         struct nilfs_sc_info *sci = from_timer(sci, t, sc_timer);
2402
2403         wake_up_process(sci->sc_timer_task);
2404 }
2405
2406 static void
2407 nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
2408 {
2409         struct nilfs_inode_info *ii, *n;
2410
2411         list_for_each_entry_safe(ii, n, head, i_dirty) {
2412                 if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
2413                         continue;
2414                 list_del_init(&ii->i_dirty);
2415                 truncate_inode_pages(&ii->vfs_inode.i_data, 0);
2416                 nilfs_btnode_cache_clear(ii->i_assoc_inode->i_mapping);
2417                 iput(&ii->vfs_inode);
2418         }
2419 }
2420
2421 int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
2422                          void **kbufs)
2423 {
2424         struct the_nilfs *nilfs = sb->s_fs_info;
2425         struct nilfs_sc_info *sci = nilfs->ns_writer;
2426         struct nilfs_transaction_info ti;
2427         int err;
2428
2429         if (unlikely(!sci))
2430                 return -EROFS;
2431
2432         nilfs_transaction_lock(sb, &ti, 1);
2433
2434         err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
2435         if (unlikely(err))
2436                 goto out_unlock;
2437
2438         err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
2439         if (unlikely(err)) {
2440                 nilfs_mdt_restore_from_shadow_map(nilfs->ns_dat);
2441                 goto out_unlock;
2442         }
2443
2444         sci->sc_freesegs = kbufs[4];
2445         sci->sc_nfreesegs = argv[4].v_nmembs;
2446         list_splice_tail_init(&nilfs->ns_gc_inodes, &sci->sc_gc_inodes);
2447
2448         for (;;) {
2449                 err = nilfs_segctor_construct(sci, SC_LSEG_SR);
2450                 nilfs_remove_written_gcinodes(nilfs, &sci->sc_gc_inodes);
2451
2452                 if (likely(!err))
2453                         break;
2454
2455                 nilfs_warn(sb, "error %d cleaning segments", err);
2456                 set_current_state(TASK_INTERRUPTIBLE);
2457                 schedule_timeout(sci->sc_interval);
2458         }
2459         if (nilfs_test_opt(nilfs, DISCARD)) {
2460                 int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
2461                                                  sci->sc_nfreesegs);
2462                 if (ret) {
2463                         nilfs_warn(sb,
2464                                    "error %d on discard request, turning discards off for the device",
2465                                    ret);
2466                         nilfs_clear_opt(nilfs, DISCARD);
2467                 }
2468         }
2469
2470  out_unlock:
2471         sci->sc_freesegs = NULL;
2472         sci->sc_nfreesegs = 0;
2473         nilfs_mdt_clear_shadow_map(nilfs->ns_dat);
2474         nilfs_transaction_unlock(sb);
2475         return err;
2476 }
2477
2478 static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
2479 {
2480         struct nilfs_transaction_info ti;
2481
2482         nilfs_transaction_lock(sci->sc_super, &ti, 0);
2483         nilfs_segctor_construct(sci, mode);
2484
2485         /*
2486          * Unclosed segment should be retried.  We do this using sc_timer.
2487          * Timeout of sc_timer will invoke complete construction which leads
2488          * to close the current logical segment.
2489          */
2490         if (test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags))
2491                 nilfs_segctor_start_timer(sci);
2492
2493         nilfs_transaction_unlock(sci->sc_super);
2494 }
2495
2496 static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
2497 {
2498         int mode = 0;
2499
2500         spin_lock(&sci->sc_state_lock);
2501         mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
2502                 SC_FLUSH_DAT : SC_FLUSH_FILE;
2503         spin_unlock(&sci->sc_state_lock);
2504
2505         if (mode) {
2506                 nilfs_segctor_do_construct(sci, mode);
2507
2508                 spin_lock(&sci->sc_state_lock);
2509                 sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
2510                         ~FLUSH_FILE_BIT : ~FLUSH_DAT_BIT;
2511                 spin_unlock(&sci->sc_state_lock);
2512         }
2513         clear_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
2514 }
2515
2516 static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
2517 {
2518         if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2519             time_before(jiffies, sci->sc_lseg_stime + sci->sc_mjcp_freq)) {
2520                 if (!(sci->sc_flush_request & ~FLUSH_FILE_BIT))
2521                         return SC_FLUSH_FILE;
2522                 else if (!(sci->sc_flush_request & ~FLUSH_DAT_BIT))
2523                         return SC_FLUSH_DAT;
2524         }
2525         return SC_LSEG_SR;
2526 }
2527
2528 /**
2529  * nilfs_segctor_thread - main loop of the segment constructor thread.
2530  * @arg: pointer to a struct nilfs_sc_info.
2531  *
2532  * nilfs_segctor_thread() initializes a timer and serves as a daemon
2533  * to execute segment constructions.
2534  */
2535 static int nilfs_segctor_thread(void *arg)
2536 {
2537         struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
2538         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2539         int timeout = 0;
2540
2541         sci->sc_timer_task = current;
2542
2543         /* start sync. */
2544         sci->sc_task = current;
2545         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_start_thread() */
2546         nilfs_info(sci->sc_super,
2547                    "segctord starting. Construction interval = %lu seconds, CP frequency < %lu seconds",
2548                    sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
2549
2550         set_freezable();
2551         spin_lock(&sci->sc_state_lock);
2552  loop:
2553         for (;;) {
2554                 int mode;
2555
2556                 if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2557                         goto end_thread;
2558
2559                 if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2560                         mode = SC_LSEG_SR;
2561                 else if (sci->sc_flush_request)
2562                         mode = nilfs_segctor_flush_mode(sci);
2563                 else
2564                         break;
2565
2566                 spin_unlock(&sci->sc_state_lock);
2567                 nilfs_segctor_thread_construct(sci, mode);
2568                 spin_lock(&sci->sc_state_lock);
2569                 timeout = 0;
2570         }
2571
2572
2573         if (freezing(current)) {
2574                 spin_unlock(&sci->sc_state_lock);
2575                 try_to_freeze();
2576                 spin_lock(&sci->sc_state_lock);
2577         } else {
2578                 DEFINE_WAIT(wait);
2579                 int should_sleep = 1;
2580
2581                 prepare_to_wait(&sci->sc_wait_daemon, &wait,
2582                                 TASK_INTERRUPTIBLE);
2583
2584                 if (sci->sc_seq_request != sci->sc_seq_done)
2585                         should_sleep = 0;
2586                 else if (sci->sc_flush_request)
2587                         should_sleep = 0;
2588                 else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2589                         should_sleep = time_before(jiffies,
2590                                         sci->sc_timer.expires);
2591
2592                 if (should_sleep) {
2593                         spin_unlock(&sci->sc_state_lock);
2594                         schedule();
2595                         spin_lock(&sci->sc_state_lock);
2596                 }
2597                 finish_wait(&sci->sc_wait_daemon, &wait);
2598                 timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2599                            time_after_eq(jiffies, sci->sc_timer.expires));
2600
2601                 if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2602                         set_nilfs_discontinued(nilfs);
2603         }
2604         goto loop;
2605
2606  end_thread:
2607         /* end sync. */
2608         sci->sc_task = NULL;
2609         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
2610         spin_unlock(&sci->sc_state_lock);
2611         return 0;
2612 }
2613
2614 static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2615 {
2616         struct task_struct *t;
2617
2618         t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2619         if (IS_ERR(t)) {
2620                 int err = PTR_ERR(t);
2621
2622                 nilfs_err(sci->sc_super, "error %d creating segctord thread",
2623                           err);
2624                 return err;
2625         }
2626         wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2627         return 0;
2628 }
2629
2630 static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2631         __acquires(&sci->sc_state_lock)
2632         __releases(&sci->sc_state_lock)
2633 {
2634         sci->sc_state |= NILFS_SEGCTOR_QUIT;
2635
2636         while (sci->sc_task) {
2637                 wake_up(&sci->sc_wait_daemon);
2638                 spin_unlock(&sci->sc_state_lock);
2639                 wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2640                 spin_lock(&sci->sc_state_lock);
2641         }
2642 }
2643
2644 /*
2645  * Setup & clean-up functions
2646  */
2647 static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
2648                                                struct nilfs_root *root)
2649 {
2650         struct the_nilfs *nilfs = sb->s_fs_info;
2651         struct nilfs_sc_info *sci;
2652
2653         sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2654         if (!sci)
2655                 return NULL;
2656
2657         sci->sc_super = sb;
2658
2659         nilfs_get_root(root);
2660         sci->sc_root = root;
2661
2662         init_waitqueue_head(&sci->sc_wait_request);
2663         init_waitqueue_head(&sci->sc_wait_daemon);
2664         init_waitqueue_head(&sci->sc_wait_task);
2665         spin_lock_init(&sci->sc_state_lock);
2666         INIT_LIST_HEAD(&sci->sc_dirty_files);
2667         INIT_LIST_HEAD(&sci->sc_segbufs);
2668         INIT_LIST_HEAD(&sci->sc_write_logs);
2669         INIT_LIST_HEAD(&sci->sc_gc_inodes);
2670         INIT_LIST_HEAD(&sci->sc_iput_queue);
2671         INIT_WORK(&sci->sc_iput_work, nilfs_iput_work_func);
2672         timer_setup(&sci->sc_timer, nilfs_construction_timeout, 0);
2673
2674         sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2675         sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2676         sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2677
2678         if (nilfs->ns_interval)
2679                 sci->sc_interval = HZ * nilfs->ns_interval;
2680         if (nilfs->ns_watermark)
2681                 sci->sc_watermark = nilfs->ns_watermark;
2682         return sci;
2683 }
2684
2685 static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2686 {
2687         int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2688
2689         /*
2690          * The segctord thread was stopped and its timer was removed.
2691          * But some tasks remain.
2692          */
2693         do {
2694                 struct nilfs_transaction_info ti;
2695
2696                 nilfs_transaction_lock(sci->sc_super, &ti, 0);
2697                 ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2698                 nilfs_transaction_unlock(sci->sc_super);
2699
2700                 flush_work(&sci->sc_iput_work);
2701
2702         } while (ret && ret != -EROFS && retrycount-- > 0);
2703 }
2704
2705 /**
2706  * nilfs_segctor_destroy - destroy the segment constructor.
2707  * @sci: nilfs_sc_info
2708  *
2709  * nilfs_segctor_destroy() kills the segctord thread and frees
2710  * the nilfs_sc_info struct.
2711  * Caller must hold the segment semaphore.
2712  */
2713 static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2714 {
2715         struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2716         int flag;
2717
2718         up_write(&nilfs->ns_segctor_sem);
2719
2720         spin_lock(&sci->sc_state_lock);
2721         nilfs_segctor_kill_thread(sci);
2722         flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2723                 || sci->sc_seq_request != sci->sc_seq_done);
2724         spin_unlock(&sci->sc_state_lock);
2725
2726         if (flush_work(&sci->sc_iput_work))
2727                 flag = true;
2728
2729         if (flag || !nilfs_segctor_confirm(sci))
2730                 nilfs_segctor_write_out(sci);
2731
2732         if (!list_empty(&sci->sc_dirty_files)) {
2733                 nilfs_warn(sci->sc_super,
2734                            "disposed unprocessed dirty file(s) when stopping log writer");
2735                 nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2736         }
2737
2738         if (!list_empty(&sci->sc_iput_queue)) {
2739                 nilfs_warn(sci->sc_super,
2740                            "disposed unprocessed inode(s) in iput queue when stopping log writer");
2741                 nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 1);
2742         }
2743
2744         WARN_ON(!list_empty(&sci->sc_segbufs));
2745         WARN_ON(!list_empty(&sci->sc_write_logs));
2746
2747         nilfs_put_root(sci->sc_root);
2748
2749         down_write(&nilfs->ns_segctor_sem);
2750
2751         timer_shutdown_sync(&sci->sc_timer);
2752         kfree(sci);
2753 }
2754
2755 /**
2756  * nilfs_attach_log_writer - attach log writer
2757  * @sb: super block instance
2758  * @root: root object of the current filesystem tree
2759  *
2760  * This allocates a log writer object, initializes it, and starts the
2761  * log writer.
2762  *
2763  * Return Value: On success, 0 is returned. On error, one of the following
2764  * negative error code is returned.
2765  *
2766  * %-ENOMEM - Insufficient memory available.
2767  */
2768 int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
2769 {
2770         struct the_nilfs *nilfs = sb->s_fs_info;
2771         int err;
2772
2773         if (nilfs->ns_writer) {
2774                 /*
2775                  * This happens if the filesystem is made read-only by
2776                  * __nilfs_error or nilfs_remount and then remounted
2777                  * read/write.  In these cases, reuse the existing
2778                  * writer.
2779                  */
2780                 return 0;
2781         }
2782
2783         nilfs->ns_writer = nilfs_segctor_new(sb, root);
2784         if (!nilfs->ns_writer)
2785                 return -ENOMEM;
2786
2787         inode_attach_wb(nilfs->ns_bdev->bd_inode, NULL);
2788
2789         err = nilfs_segctor_start_thread(nilfs->ns_writer);
2790         if (unlikely(err))
2791                 nilfs_detach_log_writer(sb);
2792
2793         return err;
2794 }
2795
2796 /**
2797  * nilfs_detach_log_writer - destroy log writer
2798  * @sb: super block instance
2799  *
2800  * This kills log writer daemon, frees the log writer object, and
2801  * destroys list of dirty files.
2802  */
2803 void nilfs_detach_log_writer(struct super_block *sb)
2804 {
2805         struct the_nilfs *nilfs = sb->s_fs_info;
2806         LIST_HEAD(garbage_list);
2807
2808         down_write(&nilfs->ns_segctor_sem);
2809         if (nilfs->ns_writer) {
2810                 nilfs_segctor_destroy(nilfs->ns_writer);
2811                 nilfs->ns_writer = NULL;
2812         }
2813         set_nilfs_purging(nilfs);
2814
2815         /* Force to free the list of dirty files */
2816         spin_lock(&nilfs->ns_inode_lock);
2817         if (!list_empty(&nilfs->ns_dirty_files)) {
2818                 list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2819                 nilfs_warn(sb,
2820                            "disposed unprocessed dirty file(s) when detaching log writer");
2821         }
2822         spin_unlock(&nilfs->ns_inode_lock);
2823         up_write(&nilfs->ns_segctor_sem);
2824
2825         nilfs_dispose_list(nilfs, &garbage_list, 1);
2826         clear_nilfs_purging(nilfs);
2827 }