linux/fs/nilfs2/segment.c
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   1/*
   2 * segment.c - NILFS segment constructor.
   3 *
   4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19 *
  20 * Written by Ryusuke Konishi <ryusuke@osrg.net>
  21 *
  22 */
  23
  24#include <linux/pagemap.h>
  25#include <linux/buffer_head.h>
  26#include <linux/writeback.h>
  27#include <linux/bio.h>
  28#include <linux/completion.h>
  29#include <linux/blkdev.h>
  30#include <linux/backing-dev.h>
  31#include <linux/freezer.h>
  32#include <linux/kthread.h>
  33#include <linux/crc32.h>
  34#include <linux/pagevec.h>
  35#include <linux/slab.h>
  36#include "nilfs.h"
  37#include "btnode.h"
  38#include "page.h"
  39#include "segment.h"
  40#include "sufile.h"
  41#include "cpfile.h"
  42#include "ifile.h"
  43#include "segbuf.h"
  44
  45
  46/*
  47 * Segment constructor
  48 */
  49#define SC_N_INODEVEC   16   /* Size of locally allocated inode vector */
  50
  51#define SC_MAX_SEGDELTA 64   /* Upper limit of the number of segments
  52                                appended in collection retry loop */
  53
  54/* Construction mode */
  55enum {
  56        SC_LSEG_SR = 1, /* Make a logical segment having a super root */
  57        SC_LSEG_DSYNC,  /* Flush data blocks of a given file and make
  58                           a logical segment without a super root */
  59        SC_FLUSH_FILE,  /* Flush data files, leads to segment writes without
  60                           creating a checkpoint */
  61        SC_FLUSH_DAT,   /* Flush DAT file. This also creates segments without
  62                           a checkpoint */
  63};
  64
  65/* Stage numbers of dirty block collection */
  66enum {
  67        NILFS_ST_INIT = 0,
  68        NILFS_ST_GC,            /* Collecting dirty blocks for GC */
  69        NILFS_ST_FILE,
  70        NILFS_ST_IFILE,
  71        NILFS_ST_CPFILE,
  72        NILFS_ST_SUFILE,
  73        NILFS_ST_DAT,
  74        NILFS_ST_SR,            /* Super root */
  75        NILFS_ST_DSYNC,         /* Data sync blocks */
  76        NILFS_ST_DONE,
  77};
  78
  79/* State flags of collection */
  80#define NILFS_CF_NODE           0x0001  /* Collecting node blocks */
  81#define NILFS_CF_IFILE_STARTED  0x0002  /* IFILE stage has started */
  82#define NILFS_CF_SUFREED        0x0004  /* segment usages has been freed */
  83#define NILFS_CF_HISTORY_MASK   (NILFS_CF_IFILE_STARTED | NILFS_CF_SUFREED)
  84
  85/* Operations depending on the construction mode and file type */
  86struct nilfs_sc_operations {
  87        int (*collect_data)(struct nilfs_sc_info *, struct buffer_head *,
  88                            struct inode *);
  89        int (*collect_node)(struct nilfs_sc_info *, struct buffer_head *,
  90                            struct inode *);
  91        int (*collect_bmap)(struct nilfs_sc_info *, struct buffer_head *,
  92                            struct inode *);
  93        void (*write_data_binfo)(struct nilfs_sc_info *,
  94                                 struct nilfs_segsum_pointer *,
  95                                 union nilfs_binfo *);
  96        void (*write_node_binfo)(struct nilfs_sc_info *,
  97                                 struct nilfs_segsum_pointer *,
  98                                 union nilfs_binfo *);
  99};
 100
 101/*
 102 * Other definitions
 103 */
 104static void nilfs_segctor_start_timer(struct nilfs_sc_info *);
 105static void nilfs_segctor_do_flush(struct nilfs_sc_info *, int);
 106static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *);
 107static void nilfs_dispose_list(struct the_nilfs *, struct list_head *, int);
 108
 109#define nilfs_cnt32_gt(a, b)   \
 110        (typecheck(__u32, a) && typecheck(__u32, b) && \
 111         ((__s32)(b) - (__s32)(a) < 0))
 112#define nilfs_cnt32_ge(a, b)   \
 113        (typecheck(__u32, a) && typecheck(__u32, b) && \
 114         ((__s32)(a) - (__s32)(b) >= 0))
 115#define nilfs_cnt32_lt(a, b)  nilfs_cnt32_gt(b, a)
 116#define nilfs_cnt32_le(a, b)  nilfs_cnt32_ge(b, a)
 117
 118static int nilfs_prepare_segment_lock(struct nilfs_transaction_info *ti)
 119{
 120        struct nilfs_transaction_info *cur_ti = current->journal_info;
 121        void *save = NULL;
 122
 123        if (cur_ti) {
 124                if (cur_ti->ti_magic == NILFS_TI_MAGIC)
 125                        return ++cur_ti->ti_count;
 126                else {
 127                        /*
 128                         * If journal_info field is occupied by other FS,
 129                         * it is saved and will be restored on
 130                         * nilfs_transaction_commit().
 131                         */
 132                        printk(KERN_WARNING
 133                               "NILFS warning: journal info from a different "
 134                               "FS\n");
 135                        save = current->journal_info;
 136                }
 137        }
 138        if (!ti) {
 139                ti = kmem_cache_alloc(nilfs_transaction_cachep, GFP_NOFS);
 140                if (!ti)
 141                        return -ENOMEM;
 142                ti->ti_flags = NILFS_TI_DYNAMIC_ALLOC;
 143        } else {
 144                ti->ti_flags = 0;
 145        }
 146        ti->ti_count = 0;
 147        ti->ti_save = save;
 148        ti->ti_magic = NILFS_TI_MAGIC;
 149        current->journal_info = ti;
 150        return 0;
 151}
 152
 153/**
 154 * nilfs_transaction_begin - start indivisible file operations.
 155 * @sb: super block
 156 * @ti: nilfs_transaction_info
 157 * @vacancy_check: flags for vacancy rate checks
 158 *
 159 * nilfs_transaction_begin() acquires a reader/writer semaphore, called
 160 * the segment semaphore, to make a segment construction and write tasks
 161 * exclusive.  The function is used with nilfs_transaction_commit() in pairs.
 162 * The region enclosed by these two functions can be nested.  To avoid a
 163 * deadlock, the semaphore is only acquired or released in the outermost call.
 164 *
 165 * This function allocates a nilfs_transaction_info struct to keep context
 166 * information on it.  It is initialized and hooked onto the current task in
 167 * the outermost call.  If a pre-allocated struct is given to @ti, it is used
 168 * instead; otherwise a new struct is assigned from a slab.
 169 *
 170 * When @vacancy_check flag is set, this function will check the amount of
 171 * free space, and will wait for the GC to reclaim disk space if low capacity.
 172 *
 173 * Return Value: On success, 0 is returned. On error, one of the following
 174 * negative error code is returned.
 175 *
 176 * %-ENOMEM - Insufficient memory available.
 177 *
 178 * %-ENOSPC - No space left on device
 179 */
 180int nilfs_transaction_begin(struct super_block *sb,
 181                            struct nilfs_transaction_info *ti,
 182                            int vacancy_check)
 183{
 184        struct the_nilfs *nilfs;
 185        int ret = nilfs_prepare_segment_lock(ti);
 186
 187        if (unlikely(ret < 0))
 188                return ret;
 189        if (ret > 0)
 190                return 0;
 191
 192        sb_start_intwrite(sb);
 193
 194        nilfs = sb->s_fs_info;
 195        down_read(&nilfs->ns_segctor_sem);
 196        if (vacancy_check && nilfs_near_disk_full(nilfs)) {
 197                up_read(&nilfs->ns_segctor_sem);
 198                ret = -ENOSPC;
 199                goto failed;
 200        }
 201        return 0;
 202
 203 failed:
 204        ti = current->journal_info;
 205        current->journal_info = ti->ti_save;
 206        if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 207                kmem_cache_free(nilfs_transaction_cachep, ti);
 208        sb_end_intwrite(sb);
 209        return ret;
 210}
 211
 212/**
 213 * nilfs_transaction_commit - commit indivisible file operations.
 214 * @sb: super block
 215 *
 216 * nilfs_transaction_commit() releases the read semaphore which is
 217 * acquired by nilfs_transaction_begin(). This is only performed
 218 * in outermost call of this function.  If a commit flag is set,
 219 * nilfs_transaction_commit() sets a timer to start the segment
 220 * constructor.  If a sync flag is set, it starts construction
 221 * directly.
 222 */
 223int nilfs_transaction_commit(struct super_block *sb)
 224{
 225        struct nilfs_transaction_info *ti = current->journal_info;
 226        struct the_nilfs *nilfs = sb->s_fs_info;
 227        int err = 0;
 228
 229        BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 230        ti->ti_flags |= NILFS_TI_COMMIT;
 231        if (ti->ti_count > 0) {
 232                ti->ti_count--;
 233                return 0;
 234        }
 235        if (nilfs->ns_writer) {
 236                struct nilfs_sc_info *sci = nilfs->ns_writer;
 237
 238                if (ti->ti_flags & NILFS_TI_COMMIT)
 239                        nilfs_segctor_start_timer(sci);
 240                if (atomic_read(&nilfs->ns_ndirtyblks) > sci->sc_watermark)
 241                        nilfs_segctor_do_flush(sci, 0);
 242        }
 243        up_read(&nilfs->ns_segctor_sem);
 244        current->journal_info = ti->ti_save;
 245
 246        if (ti->ti_flags & NILFS_TI_SYNC)
 247                err = nilfs_construct_segment(sb);
 248        if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 249                kmem_cache_free(nilfs_transaction_cachep, ti);
 250        sb_end_intwrite(sb);
 251        return err;
 252}
 253
 254void nilfs_transaction_abort(struct super_block *sb)
 255{
 256        struct nilfs_transaction_info *ti = current->journal_info;
 257        struct the_nilfs *nilfs = sb->s_fs_info;
 258
 259        BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 260        if (ti->ti_count > 0) {
 261                ti->ti_count--;
 262                return;
 263        }
 264        up_read(&nilfs->ns_segctor_sem);
 265
 266        current->journal_info = ti->ti_save;
 267        if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 268                kmem_cache_free(nilfs_transaction_cachep, ti);
 269        sb_end_intwrite(sb);
 270}
 271
 272void nilfs_relax_pressure_in_lock(struct super_block *sb)
 273{
 274        struct the_nilfs *nilfs = sb->s_fs_info;
 275        struct nilfs_sc_info *sci = nilfs->ns_writer;
 276
 277        if (!sci || !sci->sc_flush_request)
 278                return;
 279
 280        set_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
 281        up_read(&nilfs->ns_segctor_sem);
 282
 283        down_write(&nilfs->ns_segctor_sem);
 284        if (sci->sc_flush_request &&
 285            test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags)) {
 286                struct nilfs_transaction_info *ti = current->journal_info;
 287
 288                ti->ti_flags |= NILFS_TI_WRITER;
 289                nilfs_segctor_do_immediate_flush(sci);
 290                ti->ti_flags &= ~NILFS_TI_WRITER;
 291        }
 292        downgrade_write(&nilfs->ns_segctor_sem);
 293}
 294
 295static void nilfs_transaction_lock(struct super_block *sb,
 296                                   struct nilfs_transaction_info *ti,
 297                                   int gcflag)
 298{
 299        struct nilfs_transaction_info *cur_ti = current->journal_info;
 300        struct the_nilfs *nilfs = sb->s_fs_info;
 301        struct nilfs_sc_info *sci = nilfs->ns_writer;
 302
 303        WARN_ON(cur_ti);
 304        ti->ti_flags = NILFS_TI_WRITER;
 305        ti->ti_count = 0;
 306        ti->ti_save = cur_ti;
 307        ti->ti_magic = NILFS_TI_MAGIC;
 308        INIT_LIST_HEAD(&ti->ti_garbage);
 309        current->journal_info = ti;
 310
 311        for (;;) {
 312                down_write(&nilfs->ns_segctor_sem);
 313                if (!test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags))
 314                        break;
 315
 316                nilfs_segctor_do_immediate_flush(sci);
 317
 318                up_write(&nilfs->ns_segctor_sem);
 319                yield();
 320        }
 321        if (gcflag)
 322                ti->ti_flags |= NILFS_TI_GC;
 323}
 324
 325static void nilfs_transaction_unlock(struct super_block *sb)
 326{
 327        struct nilfs_transaction_info *ti = current->journal_info;
 328        struct the_nilfs *nilfs = sb->s_fs_info;
 329
 330        BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 331        BUG_ON(ti->ti_count > 0);
 332
 333        up_write(&nilfs->ns_segctor_sem);
 334        current->journal_info = ti->ti_save;
 335        if (!list_empty(&ti->ti_garbage))
 336                nilfs_dispose_list(nilfs, &ti->ti_garbage, 0);
 337}
 338
 339static void *nilfs_segctor_map_segsum_entry(struct nilfs_sc_info *sci,
 340                                            struct nilfs_segsum_pointer *ssp,
 341                                            unsigned bytes)
 342{
 343        struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 344        unsigned blocksize = sci->sc_super->s_blocksize;
 345        void *p;
 346
 347        if (unlikely(ssp->offset + bytes > blocksize)) {
 348                ssp->offset = 0;
 349                BUG_ON(NILFS_SEGBUF_BH_IS_LAST(ssp->bh,
 350                                               &segbuf->sb_segsum_buffers));
 351                ssp->bh = NILFS_SEGBUF_NEXT_BH(ssp->bh);
 352        }
 353        p = ssp->bh->b_data + ssp->offset;
 354        ssp->offset += bytes;
 355        return p;
 356}
 357
 358/**
 359 * nilfs_segctor_reset_segment_buffer - reset the current segment buffer
 360 * @sci: nilfs_sc_info
 361 */
 362static int nilfs_segctor_reset_segment_buffer(struct nilfs_sc_info *sci)
 363{
 364        struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 365        struct buffer_head *sumbh;
 366        unsigned sumbytes;
 367        unsigned flags = 0;
 368        int err;
 369
 370        if (nilfs_doing_gc())
 371                flags = NILFS_SS_GC;
 372        err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime, sci->sc_cno);
 373        if (unlikely(err))
 374                return err;
 375
 376        sumbh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
 377        sumbytes = segbuf->sb_sum.sumbytes;
 378        sci->sc_finfo_ptr.bh = sumbh;  sci->sc_finfo_ptr.offset = sumbytes;
 379        sci->sc_binfo_ptr.bh = sumbh;  sci->sc_binfo_ptr.offset = sumbytes;
 380        sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 381        return 0;
 382}
 383
 384static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
 385{
 386        sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
 387        if (NILFS_SEGBUF_IS_LAST(sci->sc_curseg, &sci->sc_segbufs))
 388                return -E2BIG; /* The current segment is filled up
 389                                  (internal code) */
 390        sci->sc_curseg = NILFS_NEXT_SEGBUF(sci->sc_curseg);
 391        return nilfs_segctor_reset_segment_buffer(sci);
 392}
 393
 394static int nilfs_segctor_add_super_root(struct nilfs_sc_info *sci)
 395{
 396        struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 397        int err;
 398
 399        if (segbuf->sb_sum.nblocks >= segbuf->sb_rest_blocks) {
 400                err = nilfs_segctor_feed_segment(sci);
 401                if (err)
 402                        return err;
 403                segbuf = sci->sc_curseg;
 404        }
 405        err = nilfs_segbuf_extend_payload(segbuf, &segbuf->sb_super_root);
 406        if (likely(!err))
 407                segbuf->sb_sum.flags |= NILFS_SS_SR;
 408        return err;
 409}
 410
 411/*
 412 * Functions for making segment summary and payloads
 413 */
 414static int nilfs_segctor_segsum_block_required(
 415        struct nilfs_sc_info *sci, const struct nilfs_segsum_pointer *ssp,
 416        unsigned binfo_size)
 417{
 418        unsigned blocksize = sci->sc_super->s_blocksize;
 419        /* Size of finfo and binfo is enough small against blocksize */
 420
 421        return ssp->offset + binfo_size +
 422                (!sci->sc_blk_cnt ? sizeof(struct nilfs_finfo) : 0) >
 423                blocksize;
 424}
 425
 426static void nilfs_segctor_begin_finfo(struct nilfs_sc_info *sci,
 427                                      struct inode *inode)
 428{
 429        sci->sc_curseg->sb_sum.nfinfo++;
 430        sci->sc_binfo_ptr = sci->sc_finfo_ptr;
 431        nilfs_segctor_map_segsum_entry(
 432                sci, &sci->sc_binfo_ptr, sizeof(struct nilfs_finfo));
 433
 434        if (NILFS_I(inode)->i_root &&
 435            !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 436                set_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
 437        /* skip finfo */
 438}
 439
 440static void nilfs_segctor_end_finfo(struct nilfs_sc_info *sci,
 441                                    struct inode *inode)
 442{
 443        struct nilfs_finfo *finfo;
 444        struct nilfs_inode_info *ii;
 445        struct nilfs_segment_buffer *segbuf;
 446        __u64 cno;
 447
 448        if (sci->sc_blk_cnt == 0)
 449                return;
 450
 451        ii = NILFS_I(inode);
 452
 453        if (test_bit(NILFS_I_GCINODE, &ii->i_state))
 454                cno = ii->i_cno;
 455        else if (NILFS_ROOT_METADATA_FILE(inode->i_ino))
 456                cno = 0;
 457        else
 458                cno = sci->sc_cno;
 459
 460        finfo = nilfs_segctor_map_segsum_entry(sci, &sci->sc_finfo_ptr,
 461                                                 sizeof(*finfo));
 462        finfo->fi_ino = cpu_to_le64(inode->i_ino);
 463        finfo->fi_nblocks = cpu_to_le32(sci->sc_blk_cnt);
 464        finfo->fi_ndatablk = cpu_to_le32(sci->sc_datablk_cnt);
 465        finfo->fi_cno = cpu_to_le64(cno);
 466
 467        segbuf = sci->sc_curseg;
 468        segbuf->sb_sum.sumbytes = sci->sc_binfo_ptr.offset +
 469                sci->sc_super->s_blocksize * (segbuf->sb_sum.nsumblk - 1);
 470        sci->sc_finfo_ptr = sci->sc_binfo_ptr;
 471        sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 472}
 473
 474static int nilfs_segctor_add_file_block(struct nilfs_sc_info *sci,
 475                                        struct buffer_head *bh,
 476                                        struct inode *inode,
 477                                        unsigned binfo_size)
 478{
 479        struct nilfs_segment_buffer *segbuf;
 480        int required, err = 0;
 481
 482 retry:
 483        segbuf = sci->sc_curseg;
 484        required = nilfs_segctor_segsum_block_required(
 485                sci, &sci->sc_binfo_ptr, binfo_size);
 486        if (segbuf->sb_sum.nblocks + required + 1 > segbuf->sb_rest_blocks) {
 487                nilfs_segctor_end_finfo(sci, inode);
 488                err = nilfs_segctor_feed_segment(sci);
 489                if (err)
 490                        return err;
 491                goto retry;
 492        }
 493        if (unlikely(required)) {
 494                err = nilfs_segbuf_extend_segsum(segbuf);
 495                if (unlikely(err))
 496                        goto failed;
 497        }
 498        if (sci->sc_blk_cnt == 0)
 499                nilfs_segctor_begin_finfo(sci, inode);
 500
 501        nilfs_segctor_map_segsum_entry(sci, &sci->sc_binfo_ptr, binfo_size);
 502        /* Substitution to vblocknr is delayed until update_blocknr() */
 503        nilfs_segbuf_add_file_buffer(segbuf, bh);
 504        sci->sc_blk_cnt++;
 505 failed:
 506        return err;
 507}
 508
 509/*
 510 * Callback functions that enumerate, mark, and collect dirty blocks
 511 */
 512static int nilfs_collect_file_data(struct nilfs_sc_info *sci,
 513                                   struct buffer_head *bh, struct inode *inode)
 514{
 515        int err;
 516
 517        err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 518        if (err < 0)
 519                return err;
 520
 521        err = nilfs_segctor_add_file_block(sci, bh, inode,
 522                                           sizeof(struct nilfs_binfo_v));
 523        if (!err)
 524                sci->sc_datablk_cnt++;
 525        return err;
 526}
 527
 528static int nilfs_collect_file_node(struct nilfs_sc_info *sci,
 529                                   struct buffer_head *bh,
 530                                   struct inode *inode)
 531{
 532        return nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 533}
 534
 535static int nilfs_collect_file_bmap(struct nilfs_sc_info *sci,
 536                                   struct buffer_head *bh,
 537                                   struct inode *inode)
 538{
 539        WARN_ON(!buffer_dirty(bh));
 540        return nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 541}
 542
 543static void nilfs_write_file_data_binfo(struct nilfs_sc_info *sci,
 544                                        struct nilfs_segsum_pointer *ssp,
 545                                        union nilfs_binfo *binfo)
 546{
 547        struct nilfs_binfo_v *binfo_v = nilfs_segctor_map_segsum_entry(
 548                sci, ssp, sizeof(*binfo_v));
 549        *binfo_v = binfo->bi_v;
 550}
 551
 552static void nilfs_write_file_node_binfo(struct nilfs_sc_info *sci,
 553                                        struct nilfs_segsum_pointer *ssp,
 554                                        union nilfs_binfo *binfo)
 555{
 556        __le64 *vblocknr = nilfs_segctor_map_segsum_entry(
 557                sci, ssp, sizeof(*vblocknr));
 558        *vblocknr = binfo->bi_v.bi_vblocknr;
 559}
 560
 561static struct nilfs_sc_operations nilfs_sc_file_ops = {
 562        .collect_data = nilfs_collect_file_data,
 563        .collect_node = nilfs_collect_file_node,
 564        .collect_bmap = nilfs_collect_file_bmap,
 565        .write_data_binfo = nilfs_write_file_data_binfo,
 566        .write_node_binfo = nilfs_write_file_node_binfo,
 567};
 568
 569static int nilfs_collect_dat_data(struct nilfs_sc_info *sci,
 570                                  struct buffer_head *bh, struct inode *inode)
 571{
 572        int err;
 573
 574        err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 575        if (err < 0)
 576                return err;
 577
 578        err = nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 579        if (!err)
 580                sci->sc_datablk_cnt++;
 581        return err;
 582}
 583
 584static int nilfs_collect_dat_bmap(struct nilfs_sc_info *sci,
 585                                  struct buffer_head *bh, struct inode *inode)
 586{
 587        WARN_ON(!buffer_dirty(bh));
 588        return nilfs_segctor_add_file_block(sci, bh, inode,
 589                                            sizeof(struct nilfs_binfo_dat));
 590}
 591
 592static void nilfs_write_dat_data_binfo(struct nilfs_sc_info *sci,
 593                                       struct nilfs_segsum_pointer *ssp,
 594                                       union nilfs_binfo *binfo)
 595{
 596        __le64 *blkoff = nilfs_segctor_map_segsum_entry(sci, ssp,
 597                                                          sizeof(*blkoff));
 598        *blkoff = binfo->bi_dat.bi_blkoff;
 599}
 600
 601static void nilfs_write_dat_node_binfo(struct nilfs_sc_info *sci,
 602                                       struct nilfs_segsum_pointer *ssp,
 603                                       union nilfs_binfo *binfo)
 604{
 605        struct nilfs_binfo_dat *binfo_dat =
 606                nilfs_segctor_map_segsum_entry(sci, ssp, sizeof(*binfo_dat));
 607        *binfo_dat = binfo->bi_dat;
 608}
 609
 610static struct nilfs_sc_operations nilfs_sc_dat_ops = {
 611        .collect_data = nilfs_collect_dat_data,
 612        .collect_node = nilfs_collect_file_node,
 613        .collect_bmap = nilfs_collect_dat_bmap,
 614        .write_data_binfo = nilfs_write_dat_data_binfo,
 615        .write_node_binfo = nilfs_write_dat_node_binfo,
 616};
 617
 618static struct nilfs_sc_operations nilfs_sc_dsync_ops = {
 619        .collect_data = nilfs_collect_file_data,
 620        .collect_node = NULL,
 621        .collect_bmap = NULL,
 622        .write_data_binfo = nilfs_write_file_data_binfo,
 623        .write_node_binfo = NULL,
 624};
 625
 626static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode,
 627                                              struct list_head *listp,
 628                                              size_t nlimit,
 629                                              loff_t start, loff_t end)
 630{
 631        struct address_space *mapping = inode->i_mapping;
 632        struct pagevec pvec;
 633        pgoff_t index = 0, last = ULONG_MAX;
 634        size_t ndirties = 0;
 635        int i;
 636
 637        if (unlikely(start != 0 || end != LLONG_MAX)) {
 638                /*
 639                 * A valid range is given for sync-ing data pages. The
 640                 * range is rounded to per-page; extra dirty buffers
 641                 * may be included if blocksize < pagesize.
 642                 */
 643                index = start >> PAGE_SHIFT;
 644                last = end >> PAGE_SHIFT;
 645        }
 646        pagevec_init(&pvec, 0);
 647 repeat:
 648        if (unlikely(index > last) ||
 649            !pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
 650                                min_t(pgoff_t, last - index,
 651                                      PAGEVEC_SIZE - 1) + 1))
 652                return ndirties;
 653
 654        for (i = 0; i < pagevec_count(&pvec); i++) {
 655                struct buffer_head *bh, *head;
 656                struct page *page = pvec.pages[i];
 657
 658                if (unlikely(page->index > last))
 659                        break;
 660
 661                lock_page(page);
 662                if (!page_has_buffers(page))
 663                        create_empty_buffers(page, 1 << inode->i_blkbits, 0);
 664                unlock_page(page);
 665
 666                bh = head = page_buffers(page);
 667                do {
 668                        if (!buffer_dirty(bh))
 669                                continue;
 670                        get_bh(bh);
 671                        list_add_tail(&bh->b_assoc_buffers, listp);
 672                        ndirties++;
 673                        if (unlikely(ndirties >= nlimit)) {
 674                                pagevec_release(&pvec);
 675                                cond_resched();
 676                                return ndirties;
 677                        }
 678                } while (bh = bh->b_this_page, bh != head);
 679        }
 680        pagevec_release(&pvec);
 681        cond_resched();
 682        goto repeat;
 683}
 684
 685static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
 686                                            struct list_head *listp)
 687{
 688        struct nilfs_inode_info *ii = NILFS_I(inode);
 689        struct address_space *mapping = &ii->i_btnode_cache;
 690        struct pagevec pvec;
 691        struct buffer_head *bh, *head;
 692        unsigned int i;
 693        pgoff_t index = 0;
 694
 695        pagevec_init(&pvec, 0);
 696
 697        while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
 698                                  PAGEVEC_SIZE)) {
 699                for (i = 0; i < pagevec_count(&pvec); i++) {
 700                        bh = head = page_buffers(pvec.pages[i]);
 701                        do {
 702                                if (buffer_dirty(bh)) {
 703                                        get_bh(bh);
 704                                        list_add_tail(&bh->b_assoc_buffers,
 705                                                      listp);
 706                                }
 707                                bh = bh->b_this_page;
 708                        } while (bh != head);
 709                }
 710                pagevec_release(&pvec);
 711                cond_resched();
 712        }
 713}
 714
 715static void nilfs_dispose_list(struct the_nilfs *nilfs,
 716                               struct list_head *head, int force)
 717{
 718        struct nilfs_inode_info *ii, *n;
 719        struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
 720        unsigned nv = 0;
 721
 722        while (!list_empty(head)) {
 723                spin_lock(&nilfs->ns_inode_lock);
 724                list_for_each_entry_safe(ii, n, head, i_dirty) {
 725                        list_del_init(&ii->i_dirty);
 726                        if (force) {
 727                                if (unlikely(ii->i_bh)) {
 728                                        brelse(ii->i_bh);
 729                                        ii->i_bh = NULL;
 730                                }
 731                        } else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
 732                                set_bit(NILFS_I_QUEUED, &ii->i_state);
 733                                list_add_tail(&ii->i_dirty,
 734                                              &nilfs->ns_dirty_files);
 735                                continue;
 736                        }
 737                        ivec[nv++] = ii;
 738                        if (nv == SC_N_INODEVEC)
 739                                break;
 740                }
 741                spin_unlock(&nilfs->ns_inode_lock);
 742
 743                for (pii = ivec; nv > 0; pii++, nv--)
 744                        iput(&(*pii)->vfs_inode);
 745        }
 746}
 747
 748static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
 749                                     struct nilfs_root *root)
 750{
 751        int ret = 0;
 752
 753        if (nilfs_mdt_fetch_dirty(root->ifile))
 754                ret++;
 755        if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
 756                ret++;
 757        if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
 758                ret++;
 759        if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
 760                ret++;
 761        return ret;
 762}
 763
 764static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 765{
 766        return list_empty(&sci->sc_dirty_files) &&
 767                !test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
 768                sci->sc_nfreesegs == 0 &&
 769                (!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
 770}
 771
 772static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 773{
 774        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 775        int ret = 0;
 776
 777        if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
 778                set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
 779
 780        spin_lock(&nilfs->ns_inode_lock);
 781        if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
 782                ret++;
 783
 784        spin_unlock(&nilfs->ns_inode_lock);
 785        return ret;
 786}
 787
 788static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 789{
 790        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 791
 792        nilfs_mdt_clear_dirty(sci->sc_root->ifile);
 793        nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
 794        nilfs_mdt_clear_dirty(nilfs->ns_sufile);
 795        nilfs_mdt_clear_dirty(nilfs->ns_dat);
 796}
 797
 798static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
 799{
 800        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 801        struct buffer_head *bh_cp;
 802        struct nilfs_checkpoint *raw_cp;
 803        int err;
 804
 805        /* XXX: this interface will be changed */
 806        err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 1,
 807                                          &raw_cp, &bh_cp);
 808        if (likely(!err)) {
 809                /* The following code is duplicated with cpfile.  But, it is
 810                   needed to collect the checkpoint even if it was not newly
 811                   created */
 812                mark_buffer_dirty(bh_cp);
 813                nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
 814                nilfs_cpfile_put_checkpoint(
 815                        nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 816        } else
 817                WARN_ON(err == -EINVAL || err == -ENOENT);
 818
 819        return err;
 820}
 821
 822static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
 823{
 824        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 825        struct buffer_head *bh_cp;
 826        struct nilfs_checkpoint *raw_cp;
 827        int err;
 828
 829        err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
 830                                          &raw_cp, &bh_cp);
 831        if (unlikely(err)) {
 832                WARN_ON(err == -EINVAL || err == -ENOENT);
 833                goto failed_ibh;
 834        }
 835        raw_cp->cp_snapshot_list.ssl_next = 0;
 836        raw_cp->cp_snapshot_list.ssl_prev = 0;
 837        raw_cp->cp_inodes_count =
 838                cpu_to_le64(atomic_read(&sci->sc_root->inodes_count));
 839        raw_cp->cp_blocks_count =
 840                cpu_to_le64(atomic_read(&sci->sc_root->blocks_count));
 841        raw_cp->cp_nblk_inc =
 842                cpu_to_le64(sci->sc_nblk_inc + sci->sc_nblk_this_inc);
 843        raw_cp->cp_create = cpu_to_le64(sci->sc_seg_ctime);
 844        raw_cp->cp_cno = cpu_to_le64(nilfs->ns_cno);
 845
 846        if (test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 847                nilfs_checkpoint_clear_minor(raw_cp);
 848        else
 849                nilfs_checkpoint_set_minor(raw_cp);
 850
 851        nilfs_write_inode_common(sci->sc_root->ifile,
 852                                 &raw_cp->cp_ifile_inode, 1);
 853        nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 854        return 0;
 855
 856 failed_ibh:
 857        return err;
 858}
 859
 860static void nilfs_fill_in_file_bmap(struct inode *ifile,
 861                                    struct nilfs_inode_info *ii)
 862
 863{
 864        struct buffer_head *ibh;
 865        struct nilfs_inode *raw_inode;
 866
 867        if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
 868                ibh = ii->i_bh;
 869                BUG_ON(!ibh);
 870                raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
 871                                                  ibh);
 872                nilfs_bmap_write(ii->i_bmap, raw_inode);
 873                nilfs_ifile_unmap_inode(ifile, ii->vfs_inode.i_ino, ibh);
 874        }
 875}
 876
 877static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
 878{
 879        struct nilfs_inode_info *ii;
 880
 881        list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
 882                nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
 883                set_bit(NILFS_I_COLLECTED, &ii->i_state);
 884        }
 885}
 886
 887static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 888                                             struct the_nilfs *nilfs)
 889{
 890        struct buffer_head *bh_sr;
 891        struct nilfs_super_root *raw_sr;
 892        unsigned isz, srsz;
 893
 894        bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
 895        raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 896        isz = nilfs->ns_inode_size;
 897        srsz = NILFS_SR_BYTES(isz);
 898
 899        raw_sr->sr_bytes = cpu_to_le16(srsz);
 900        raw_sr->sr_nongc_ctime
 901                = cpu_to_le64(nilfs_doing_gc() ?
 902                              nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
 903        raw_sr->sr_flags = 0;
 904
 905        nilfs_write_inode_common(nilfs->ns_dat, (void *)raw_sr +
 906                                 NILFS_SR_DAT_OFFSET(isz), 1);
 907        nilfs_write_inode_common(nilfs->ns_cpfile, (void *)raw_sr +
 908                                 NILFS_SR_CPFILE_OFFSET(isz), 1);
 909        nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
 910                                 NILFS_SR_SUFILE_OFFSET(isz), 1);
 911        memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
 912}
 913
 914static void nilfs_redirty_inodes(struct list_head *head)
 915{
 916        struct nilfs_inode_info *ii;
 917
 918        list_for_each_entry(ii, head, i_dirty) {
 919                if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
 920                        clear_bit(NILFS_I_COLLECTED, &ii->i_state);
 921        }
 922}
 923
 924static void nilfs_drop_collected_inodes(struct list_head *head)
 925{
 926        struct nilfs_inode_info *ii;
 927
 928        list_for_each_entry(ii, head, i_dirty) {
 929                if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
 930                        continue;
 931
 932                clear_bit(NILFS_I_INODE_DIRTY, &ii->i_state);
 933                set_bit(NILFS_I_UPDATED, &ii->i_state);
 934        }
 935}
 936
 937static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
 938                                       struct inode *inode,
 939                                       struct list_head *listp,
 940                                       int (*collect)(struct nilfs_sc_info *,
 941                                                      struct buffer_head *,
 942                                                      struct inode *))
 943{
 944        struct buffer_head *bh, *n;
 945        int err = 0;
 946
 947        if (collect) {
 948                list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
 949                        list_del_init(&bh->b_assoc_buffers);
 950                        err = collect(sci, bh, inode);
 951                        brelse(bh);
 952                        if (unlikely(err))
 953                                goto dispose_buffers;
 954                }
 955                return 0;
 956        }
 957
 958 dispose_buffers:
 959        while (!list_empty(listp)) {
 960                bh = list_first_entry(listp, struct buffer_head,
 961                                      b_assoc_buffers);
 962                list_del_init(&bh->b_assoc_buffers);
 963                brelse(bh);
 964        }
 965        return err;
 966}
 967
 968static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
 969{
 970        /* Remaining number of blocks within segment buffer */
 971        return sci->sc_segbuf_nblocks -
 972                (sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
 973}
 974
 975static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
 976                                   struct inode *inode,
 977                                   struct nilfs_sc_operations *sc_ops)
 978{
 979        LIST_HEAD(data_buffers);
 980        LIST_HEAD(node_buffers);
 981        int err;
 982
 983        if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
 984                size_t n, rest = nilfs_segctor_buffer_rest(sci);
 985
 986                n = nilfs_lookup_dirty_data_buffers(
 987                        inode, &data_buffers, rest + 1, 0, LLONG_MAX);
 988                if (n > rest) {
 989                        err = nilfs_segctor_apply_buffers(
 990                                sci, inode, &data_buffers,
 991                                sc_ops->collect_data);
 992                        BUG_ON(!err); /* always receive -E2BIG or true error */
 993                        goto break_or_fail;
 994                }
 995        }
 996        nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
 997
 998        if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
 999                err = nilfs_segctor_apply_buffers(
1000                        sci, inode, &data_buffers, sc_ops->collect_data);
1001                if (unlikely(err)) {
1002                        /* dispose node list */
1003                        nilfs_segctor_apply_buffers(
1004                                sci, inode, &node_buffers, NULL);
1005                        goto break_or_fail;
1006                }
1007                sci->sc_stage.flags |= NILFS_CF_NODE;
1008        }
1009        /* Collect node */
1010        err = nilfs_segctor_apply_buffers(
1011                sci, inode, &node_buffers, sc_ops->collect_node);
1012        if (unlikely(err))
1013                goto break_or_fail;
1014
1015        nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1016        err = nilfs_segctor_apply_buffers(
1017                sci, inode, &node_buffers, sc_ops->collect_bmap);
1018        if (unlikely(err))
1019                goto break_or_fail;
1020
1021        nilfs_segctor_end_finfo(sci, inode);
1022        sci->sc_stage.flags &= ~NILFS_CF_NODE;
1023
1024 break_or_fail:
1025        return err;
1026}
1027
1028static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1029                                         struct inode *inode)
1030{
1031        LIST_HEAD(data_buffers);
1032        size_t n, rest = nilfs_segctor_buffer_rest(sci);
1033        int err;
1034
1035        n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1036                                            sci->sc_dsync_start,
1037                                            sci->sc_dsync_end);
1038
1039        err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1040                                          nilfs_collect_file_data);
1041        if (!err) {
1042                nilfs_segctor_end_finfo(sci, inode);
1043                BUG_ON(n > rest);
1044                /* always receive -E2BIG or true error if n > rest */
1045        }
1046        return err;
1047}
1048
1049static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1050{
1051        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1052        struct list_head *head;
1053        struct nilfs_inode_info *ii;
1054        size_t ndone;
1055        int err = 0;
1056
1057        switch (sci->sc_stage.scnt) {
1058        case NILFS_ST_INIT:
1059                /* Pre-processes */
1060                sci->sc_stage.flags = 0;
1061
1062                if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1063                        sci->sc_nblk_inc = 0;
1064                        sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1065                        if (mode == SC_LSEG_DSYNC) {
1066                                sci->sc_stage.scnt = NILFS_ST_DSYNC;
1067                                goto dsync_mode;
1068                        }
1069                }
1070
1071                sci->sc_stage.dirty_file_ptr = NULL;
1072                sci->sc_stage.gc_inode_ptr = NULL;
1073                if (mode == SC_FLUSH_DAT) {
1074                        sci->sc_stage.scnt = NILFS_ST_DAT;
1075                        goto dat_stage;
1076                }
1077                sci->sc_stage.scnt++;  /* Fall through */
1078        case NILFS_ST_GC:
1079                if (nilfs_doing_gc()) {
1080                        head = &sci->sc_gc_inodes;
1081                        ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1082                                                head, i_dirty);
1083                        list_for_each_entry_continue(ii, head, i_dirty) {
1084                                err = nilfs_segctor_scan_file(
1085                                        sci, &ii->vfs_inode,
1086                                        &nilfs_sc_file_ops);
1087                                if (unlikely(err)) {
1088                                        sci->sc_stage.gc_inode_ptr = list_entry(
1089                                                ii->i_dirty.prev,
1090                                                struct nilfs_inode_info,
1091                                                i_dirty);
1092                                        goto break_or_fail;
1093                                }
1094                                set_bit(NILFS_I_COLLECTED, &ii->i_state);
1095                        }
1096                        sci->sc_stage.gc_inode_ptr = NULL;
1097                }
1098                sci->sc_stage.scnt++;  /* Fall through */
1099        case NILFS_ST_FILE:
1100                head = &sci->sc_dirty_files;
1101                ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1102                                        i_dirty);
1103                list_for_each_entry_continue(ii, head, i_dirty) {
1104                        clear_bit(NILFS_I_DIRTY, &ii->i_state);
1105
1106                        err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1107                                                      &nilfs_sc_file_ops);
1108                        if (unlikely(err)) {
1109                                sci->sc_stage.dirty_file_ptr =
1110                                        list_entry(ii->i_dirty.prev,
1111                                                   struct nilfs_inode_info,
1112                                                   i_dirty);
1113                                goto break_or_fail;
1114                        }
1115                        /* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1116                        /* XXX: required ? */
1117                }
1118                sci->sc_stage.dirty_file_ptr = NULL;
1119                if (mode == SC_FLUSH_FILE) {
1120                        sci->sc_stage.scnt = NILFS_ST_DONE;
1121                        return 0;
1122                }
1123                sci->sc_stage.scnt++;
1124                sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1125                /* Fall through */
1126        case NILFS_ST_IFILE:
1127                err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1128                                              &nilfs_sc_file_ops);
1129                if (unlikely(err))
1130                        break;
1131                sci->sc_stage.scnt++;
1132                /* Creating a checkpoint */
1133                err = nilfs_segctor_create_checkpoint(sci);
1134                if (unlikely(err))
1135                        break;
1136                /* Fall through */
1137        case NILFS_ST_CPFILE:
1138                err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1139                                              &nilfs_sc_file_ops);
1140                if (unlikely(err))
1141                        break;
1142                sci->sc_stage.scnt++;  /* Fall through */
1143        case NILFS_ST_SUFILE:
1144                err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1145                                         sci->sc_nfreesegs, &ndone);
1146                if (unlikely(err)) {
1147                        nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1148                                                  sci->sc_freesegs, ndone,
1149                                                  NULL);
1150                        break;
1151                }
1152                sci->sc_stage.flags |= NILFS_CF_SUFREED;
1153
1154                err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1155                                              &nilfs_sc_file_ops);
1156                if (unlikely(err))
1157                        break;
1158                sci->sc_stage.scnt++;  /* Fall through */
1159        case NILFS_ST_DAT:
1160 dat_stage:
1161                err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1162                                              &nilfs_sc_dat_ops);
1163                if (unlikely(err))
1164                        break;
1165                if (mode == SC_FLUSH_DAT) {
1166                        sci->sc_stage.scnt = NILFS_ST_DONE;
1167                        return 0;
1168                }
1169                sci->sc_stage.scnt++;  /* Fall through */
1170        case NILFS_ST_SR:
1171                if (mode == SC_LSEG_SR) {
1172                        /* Appending a super root */
1173                        err = nilfs_segctor_add_super_root(sci);
1174                        if (unlikely(err))
1175                                break;
1176                }
1177                /* End of a logical segment */
1178                sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1179                sci->sc_stage.scnt = NILFS_ST_DONE;
1180                return 0;
1181        case NILFS_ST_DSYNC:
1182 dsync_mode:
1183                sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1184                ii = sci->sc_dsync_inode;
1185                if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1186                        break;
1187
1188                err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1189                if (unlikely(err))
1190                        break;
1191                sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1192                sci->sc_stage.scnt = NILFS_ST_DONE;
1193                return 0;
1194        case NILFS_ST_DONE:
1195                return 0;
1196        default:
1197                BUG();
1198        }
1199
1200 break_or_fail:
1201        return err;
1202}
1203
1204/**
1205 * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1206 * @sci: nilfs_sc_info
1207 * @nilfs: nilfs object
1208 */
1209static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1210                                            struct the_nilfs *nilfs)
1211{
1212        struct nilfs_segment_buffer *segbuf, *prev;
1213        __u64 nextnum;
1214        int err, alloc = 0;
1215
1216        segbuf = nilfs_segbuf_new(sci->sc_super);
1217        if (unlikely(!segbuf))
1218                return -ENOMEM;
1219
1220        if (list_empty(&sci->sc_write_logs)) {
1221                nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1222                                 nilfs->ns_pseg_offset, nilfs);
1223                if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1224                        nilfs_shift_to_next_segment(nilfs);
1225                        nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1226                }
1227
1228                segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1229                nextnum = nilfs->ns_nextnum;
1230
1231                if (nilfs->ns_segnum == nilfs->ns_nextnum)
1232                        /* Start from the head of a new full segment */
1233                        alloc++;
1234        } else {
1235                /* Continue logs */
1236                prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1237                nilfs_segbuf_map_cont(segbuf, prev);
1238                segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1239                nextnum = prev->sb_nextnum;
1240
1241                if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1242                        nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1243                        segbuf->sb_sum.seg_seq++;
1244                        alloc++;
1245                }
1246        }
1247
1248        err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1249        if (err)
1250                goto failed;
1251
1252        if (alloc) {
1253                err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1254                if (err)
1255                        goto failed;
1256        }
1257        nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1258
1259        BUG_ON(!list_empty(&sci->sc_segbufs));
1260        list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1261        sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1262        return 0;
1263
1264 failed:
1265        nilfs_segbuf_free(segbuf);
1266        return err;
1267}
1268
1269static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1270                                         struct the_nilfs *nilfs, int nadd)
1271{
1272        struct nilfs_segment_buffer *segbuf, *prev;
1273        struct inode *sufile = nilfs->ns_sufile;
1274        __u64 nextnextnum;
1275        LIST_HEAD(list);
1276        int err, ret, i;
1277
1278        prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1279        /*
1280         * Since the segment specified with nextnum might be allocated during
1281         * the previous construction, the buffer including its segusage may
1282         * not be dirty.  The following call ensures that the buffer is dirty
1283         * and will pin the buffer on memory until the sufile is written.
1284         */
1285        err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1286        if (unlikely(err))
1287                return err;
1288
1289        for (i = 0; i < nadd; i++) {
1290                /* extend segment info */
1291                err = -ENOMEM;
1292                segbuf = nilfs_segbuf_new(sci->sc_super);
1293                if (unlikely(!segbuf))
1294                        goto failed;
1295
1296                /* map this buffer to region of segment on-disk */
1297                nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1298                sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1299
1300                /* allocate the next next full segment */
1301                err = nilfs_sufile_alloc(sufile, &nextnextnum);
1302                if (unlikely(err))
1303                        goto failed_segbuf;
1304
1305                segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1306                nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1307
1308                list_add_tail(&segbuf->sb_list, &list);
1309                prev = segbuf;
1310        }
1311        list_splice_tail(&list, &sci->sc_segbufs);
1312        return 0;
1313
1314 failed_segbuf:
1315        nilfs_segbuf_free(segbuf);
1316 failed:
1317        list_for_each_entry(segbuf, &list, sb_list) {
1318                ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1319                WARN_ON(ret); /* never fails */
1320        }
1321        nilfs_destroy_logs(&list);
1322        return err;
1323}
1324
1325static void nilfs_free_incomplete_logs(struct list_head *logs,
1326                                       struct the_nilfs *nilfs)
1327{
1328        struct nilfs_segment_buffer *segbuf, *prev;
1329        struct inode *sufile = nilfs->ns_sufile;
1330        int ret;
1331
1332        segbuf = NILFS_FIRST_SEGBUF(logs);
1333        if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1334                ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1335                WARN_ON(ret); /* never fails */
1336        }
1337        if (atomic_read(&segbuf->sb_err)) {
1338                /* Case 1: The first segment failed */
1339                if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1340                        /* Case 1a:  Partial segment appended into an existing
1341                           segment */
1342                        nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1343                                                segbuf->sb_fseg_end);
1344                else /* Case 1b:  New full segment */
1345                        set_nilfs_discontinued(nilfs);
1346        }
1347
1348        prev = segbuf;
1349        list_for_each_entry_continue(segbuf, logs, sb_list) {
1350                if (prev->sb_nextnum != segbuf->sb_nextnum) {
1351                        ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1352                        WARN_ON(ret); /* never fails */
1353                }
1354                if (atomic_read(&segbuf->sb_err) &&
1355                    segbuf->sb_segnum != nilfs->ns_nextnum)
1356                        /* Case 2: extended segment (!= next) failed */
1357                        nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1358                prev = segbuf;
1359        }
1360}
1361
1362static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1363                                          struct inode *sufile)
1364{
1365        struct nilfs_segment_buffer *segbuf;
1366        unsigned long live_blocks;
1367        int ret;
1368
1369        list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1370                live_blocks = segbuf->sb_sum.nblocks +
1371                        (segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1372                ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1373                                                     live_blocks,
1374                                                     sci->sc_seg_ctime);
1375                WARN_ON(ret); /* always succeed because the segusage is dirty */
1376        }
1377}
1378
1379static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1380{
1381        struct nilfs_segment_buffer *segbuf;
1382        int ret;
1383
1384        segbuf = NILFS_FIRST_SEGBUF(logs);
1385        ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1386                                             segbuf->sb_pseg_start -
1387                                             segbuf->sb_fseg_start, 0);
1388        WARN_ON(ret); /* always succeed because the segusage is dirty */
1389
1390        list_for_each_entry_continue(segbuf, logs, sb_list) {
1391                ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1392                                                     0, 0);
1393                WARN_ON(ret); /* always succeed */
1394        }
1395}
1396
1397static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1398                                            struct nilfs_segment_buffer *last,
1399                                            struct inode *sufile)
1400{
1401        struct nilfs_segment_buffer *segbuf = last;
1402        int ret;
1403
1404        list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1405                sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1406                ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1407                WARN_ON(ret);
1408        }
1409        nilfs_truncate_logs(&sci->sc_segbufs, last);
1410}
1411
1412
1413static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1414                                 struct the_nilfs *nilfs, int mode)
1415{
1416        struct nilfs_cstage prev_stage = sci->sc_stage;
1417        int err, nadd = 1;
1418
1419        /* Collection retry loop */
1420        for (;;) {
1421                sci->sc_nblk_this_inc = 0;
1422                sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1423
1424                err = nilfs_segctor_reset_segment_buffer(sci);
1425                if (unlikely(err))
1426                        goto failed;
1427
1428                err = nilfs_segctor_collect_blocks(sci, mode);
1429                sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1430                if (!err)
1431                        break;
1432
1433                if (unlikely(err != -E2BIG))
1434                        goto failed;
1435
1436                /* The current segment is filled up */
1437                if (mode != SC_LSEG_SR || sci->sc_stage.scnt < NILFS_ST_CPFILE)
1438                        break;
1439
1440                nilfs_clear_logs(&sci->sc_segbufs);
1441
1442                err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1443                if (unlikely(err))
1444                        return err;
1445
1446                if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1447                        err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1448                                                        sci->sc_freesegs,
1449                                                        sci->sc_nfreesegs,
1450                                                        NULL);
1451                        WARN_ON(err); /* do not happen */
1452                }
1453                nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1454                sci->sc_stage = prev_stage;
1455        }
1456        nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1457        return 0;
1458
1459 failed:
1460        return err;
1461}
1462
1463static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1464                                      struct buffer_head *new_bh)
1465{
1466        BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1467
1468        list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1469        /* The caller must release old_bh */
1470}
1471
1472static int
1473nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1474                                     struct nilfs_segment_buffer *segbuf,
1475                                     int mode)
1476{
1477        struct inode *inode = NULL;
1478        sector_t blocknr;
1479        unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1480        unsigned long nblocks = 0, ndatablk = 0;
1481        struct nilfs_sc_operations *sc_op = NULL;
1482        struct nilfs_segsum_pointer ssp;
1483        struct nilfs_finfo *finfo = NULL;
1484        union nilfs_binfo binfo;
1485        struct buffer_head *bh, *bh_org;
1486        ino_t ino = 0;
1487        int err = 0;
1488
1489        if (!nfinfo)
1490                goto out;
1491
1492        blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1493        ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1494        ssp.offset = sizeof(struct nilfs_segment_summary);
1495
1496        list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1497                if (bh == segbuf->sb_super_root)
1498                        break;
1499                if (!finfo) {
1500                        finfo = nilfs_segctor_map_segsum_entry(
1501                                sci, &ssp, sizeof(*finfo));
1502                        ino = le64_to_cpu(finfo->fi_ino);
1503                        nblocks = le32_to_cpu(finfo->fi_nblocks);
1504                        ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1505
1506                        inode = bh->b_page->mapping->host;
1507
1508                        if (mode == SC_LSEG_DSYNC)
1509                                sc_op = &nilfs_sc_dsync_ops;
1510                        else if (ino == NILFS_DAT_INO)
1511                                sc_op = &nilfs_sc_dat_ops;
1512                        else /* file blocks */
1513                                sc_op = &nilfs_sc_file_ops;
1514                }
1515                bh_org = bh;
1516                get_bh(bh_org);
1517                err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1518                                        &binfo);
1519                if (bh != bh_org)
1520                        nilfs_list_replace_buffer(bh_org, bh);
1521                brelse(bh_org);
1522                if (unlikely(err))
1523                        goto failed_bmap;
1524
1525                if (ndatablk > 0)
1526                        sc_op->write_data_binfo(sci, &ssp, &binfo);
1527                else
1528                        sc_op->write_node_binfo(sci, &ssp, &binfo);
1529
1530                blocknr++;
1531                if (--nblocks == 0) {
1532                        finfo = NULL;
1533                        if (--nfinfo == 0)
1534                                break;
1535                } else if (ndatablk > 0)
1536                        ndatablk--;
1537        }
1538 out:
1539        return 0;
1540
1541 failed_bmap:
1542        return err;
1543}
1544
1545static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1546{
1547        struct nilfs_segment_buffer *segbuf;
1548        int err;
1549
1550        list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1551                err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1552                if (unlikely(err))
1553                        return err;
1554                nilfs_segbuf_fill_in_segsum(segbuf);
1555        }
1556        return 0;
1557}
1558
1559static void nilfs_begin_page_io(struct page *page)
1560{
1561        if (!page || PageWriteback(page))
1562                /* For split b-tree node pages, this function may be called
1563                   twice.  We ignore the 2nd or later calls by this check. */
1564                return;
1565
1566        lock_page(page);
1567        clear_page_dirty_for_io(page);
1568        set_page_writeback(page);
1569        unlock_page(page);
1570}
1571
1572static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci)
1573{
1574        struct nilfs_segment_buffer *segbuf;
1575        struct page *bd_page = NULL, *fs_page = NULL;
1576
1577        list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1578                struct buffer_head *bh;
1579
1580                list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1581                                    b_assoc_buffers) {
1582                        if (bh->b_page != bd_page) {
1583                                if (bd_page) {
1584                                        lock_page(bd_page);
1585                                        clear_page_dirty_for_io(bd_page);
1586                                        set_page_writeback(bd_page);
1587                                        unlock_page(bd_page);
1588                                }
1589                                bd_page = bh->b_page;
1590                        }
1591                }
1592
1593                list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1594                                    b_assoc_buffers) {
1595                        if (bh == segbuf->sb_super_root) {
1596                                if (bh->b_page != bd_page) {
1597                                        lock_page(bd_page);
1598                                        clear_page_dirty_for_io(bd_page);
1599                                        set_page_writeback(bd_page);
1600                                        unlock_page(bd_page);
1601                                        bd_page = bh->b_page;
1602                                }
1603                                break;
1604                        }
1605                        if (bh->b_page != fs_page) {
1606                                nilfs_begin_page_io(fs_page);
1607                                fs_page = bh->b_page;
1608                        }
1609                }
1610        }
1611        if (bd_page) {
1612                lock_page(bd_page);
1613                clear_page_dirty_for_io(bd_page);
1614                set_page_writeback(bd_page);
1615                unlock_page(bd_page);
1616        }
1617        nilfs_begin_page_io(fs_page);
1618}
1619
1620static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1621                               struct the_nilfs *nilfs)
1622{
1623        int ret;
1624
1625        ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1626        list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1627        return ret;
1628}
1629
1630static void nilfs_end_page_io(struct page *page, int err)
1631{
1632        if (!page)
1633                return;
1634
1635        if (buffer_nilfs_node(page_buffers(page)) && !PageWriteback(page)) {
1636                /*
1637                 * For b-tree node pages, this function may be called twice
1638                 * or more because they might be split in a segment.
1639                 */
1640                if (PageDirty(page)) {
1641                        /*
1642                         * For pages holding split b-tree node buffers, dirty
1643                         * flag on the buffers may be cleared discretely.
1644                         * In that case, the page is once redirtied for
1645                         * remaining buffers, and it must be cancelled if
1646                         * all the buffers get cleaned later.
1647                         */
1648                        lock_page(page);
1649                        if (nilfs_page_buffers_clean(page))
1650                                __nilfs_clear_page_dirty(page);
1651                        unlock_page(page);
1652                }
1653                return;
1654        }
1655
1656        if (!err) {
1657                if (!nilfs_page_buffers_clean(page))
1658                        __set_page_dirty_nobuffers(page);
1659                ClearPageError(page);
1660        } else {
1661                __set_page_dirty_nobuffers(page);
1662                SetPageError(page);
1663        }
1664
1665        end_page_writeback(page);
1666}
1667
1668static void nilfs_abort_logs(struct list_head *logs, int err)
1669{
1670        struct nilfs_segment_buffer *segbuf;
1671        struct page *bd_page = NULL, *fs_page = NULL;
1672        struct buffer_head *bh;
1673
1674        if (list_empty(logs))
1675                return;
1676
1677        list_for_each_entry(segbuf, logs, sb_list) {
1678                list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1679                                    b_assoc_buffers) {
1680                        if (bh->b_page != bd_page) {
1681                                if (bd_page)
1682                                        end_page_writeback(bd_page);
1683                                bd_page = bh->b_page;
1684                        }
1685                }
1686
1687                list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1688                                    b_assoc_buffers) {
1689                        if (bh == segbuf->sb_super_root) {
1690                                if (bh->b_page != bd_page) {
1691                                        end_page_writeback(bd_page);
1692                                        bd_page = bh->b_page;
1693                                }
1694                                break;
1695                        }
1696                        if (bh->b_page != fs_page) {
1697                                nilfs_end_page_io(fs_page, err);
1698                                fs_page = bh->b_page;
1699                        }
1700                }
1701        }
1702        if (bd_page)
1703                end_page_writeback(bd_page);
1704
1705        nilfs_end_page_io(fs_page, err);
1706}
1707
1708static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
1709                                             struct the_nilfs *nilfs, int err)
1710{
1711        LIST_HEAD(logs);
1712        int ret;
1713
1714        list_splice_tail_init(&sci->sc_write_logs, &logs);
1715        ret = nilfs_wait_on_logs(&logs);
1716        nilfs_abort_logs(&logs, ret ? : err);
1717
1718        list_splice_tail_init(&sci->sc_segbufs, &logs);
1719        nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
1720        nilfs_free_incomplete_logs(&logs, nilfs);
1721
1722        if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1723                ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1724                                                sci->sc_freesegs,
1725                                                sci->sc_nfreesegs,
1726                                                NULL);
1727                WARN_ON(ret); /* do not happen */
1728        }
1729
1730        nilfs_destroy_logs(&logs);
1731}
1732
1733static void nilfs_set_next_segment(struct the_nilfs *nilfs,
1734                                   struct nilfs_segment_buffer *segbuf)
1735{
1736        nilfs->ns_segnum = segbuf->sb_segnum;
1737        nilfs->ns_nextnum = segbuf->sb_nextnum;
1738        nilfs->ns_pseg_offset = segbuf->sb_pseg_start - segbuf->sb_fseg_start
1739                + segbuf->sb_sum.nblocks;
1740        nilfs->ns_seg_seq = segbuf->sb_sum.seg_seq;
1741        nilfs->ns_ctime = segbuf->sb_sum.ctime;
1742}
1743
1744static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
1745{
1746        struct nilfs_segment_buffer *segbuf;
1747        struct page *bd_page = NULL, *fs_page = NULL;
1748        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1749        int update_sr = false;
1750
1751        list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
1752                struct buffer_head *bh;
1753
1754                list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1755                                    b_assoc_buffers) {
1756                        set_buffer_uptodate(bh);
1757                        clear_buffer_dirty(bh);
1758                        if (bh->b_page != bd_page) {
1759                                if (bd_page)
1760                                        end_page_writeback(bd_page);
1761                                bd_page = bh->b_page;
1762                        }
1763                }
1764                /*
1765                 * We assume that the buffers which belong to the same page
1766                 * continue over the buffer list.
1767                 * Under this assumption, the last BHs of pages is
1768                 * identifiable by the discontinuity of bh->b_page
1769                 * (page != fs_page).
1770                 *
1771                 * For B-tree node blocks, however, this assumption is not
1772                 * guaranteed.  The cleanup code of B-tree node pages needs
1773                 * special care.
1774                 */
1775                list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1776                                    b_assoc_buffers) {
1777                        set_buffer_uptodate(bh);
1778                        clear_buffer_dirty(bh);
1779                        clear_buffer_delay(bh);
1780                        clear_buffer_nilfs_volatile(bh);
1781                        clear_buffer_nilfs_redirected(bh);
1782                        if (bh == segbuf->sb_super_root) {
1783                                if (bh->b_page != bd_page) {
1784                                        end_page_writeback(bd_page);
1785                                        bd_page = bh->b_page;
1786                                }
1787                                update_sr = true;
1788                                break;
1789                        }
1790                        if (bh->b_page != fs_page) {
1791                                nilfs_end_page_io(fs_page, 0);
1792                                fs_page = bh->b_page;
1793                        }
1794                }
1795
1796                if (!nilfs_segbuf_simplex(segbuf)) {
1797                        if (segbuf->sb_sum.flags & NILFS_SS_LOGBGN) {
1798                                set_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1799                                sci->sc_lseg_stime = jiffies;
1800                        }
1801                        if (segbuf->sb_sum.flags & NILFS_SS_LOGEND)
1802                                clear_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1803                }
1804        }
1805        /*
1806         * Since pages may continue over multiple segment buffers,
1807         * end of the last page must be checked outside of the loop.
1808         */
1809        if (bd_page)
1810                end_page_writeback(bd_page);
1811
1812        nilfs_end_page_io(fs_page, 0);
1813
1814        nilfs_drop_collected_inodes(&sci->sc_dirty_files);
1815
1816        if (nilfs_doing_gc())
1817                nilfs_drop_collected_inodes(&sci->sc_gc_inodes);
1818        else
1819                nilfs->ns_nongc_ctime = sci->sc_seg_ctime;
1820
1821        sci->sc_nblk_inc += sci->sc_nblk_this_inc;
1822
1823        segbuf = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1824        nilfs_set_next_segment(nilfs, segbuf);
1825
1826        if (update_sr) {
1827                nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
1828                                       segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
1829
1830                clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
1831                clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1832                set_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1833                nilfs_segctor_clear_metadata_dirty(sci);
1834        } else
1835                clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1836}
1837
1838static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
1839{
1840        int ret;
1841
1842        ret = nilfs_wait_on_logs(&sci->sc_write_logs);
1843        if (!ret) {
1844                nilfs_segctor_complete_write(sci);
1845                nilfs_destroy_logs(&sci->sc_write_logs);
1846        }
1847        return ret;
1848}
1849
1850static int nilfs_segctor_collect_dirty_files(struct nilfs_sc_info *sci,
1851                                             struct the_nilfs *nilfs)
1852{
1853        struct nilfs_inode_info *ii, *n;
1854        struct inode *ifile = sci->sc_root->ifile;
1855
1856        spin_lock(&nilfs->ns_inode_lock);
1857 retry:
1858        list_for_each_entry_safe(ii, n, &nilfs->ns_dirty_files, i_dirty) {
1859                if (!ii->i_bh) {
1860                        struct buffer_head *ibh;
1861                        int err;
1862
1863                        spin_unlock(&nilfs->ns_inode_lock);
1864                        err = nilfs_ifile_get_inode_block(
1865                                ifile, ii->vfs_inode.i_ino, &ibh);
1866                        if (unlikely(err)) {
1867                                nilfs_warning(sci->sc_super, __func__,
1868                                              "failed to get inode block.\n");
1869                                return err;
1870                        }
1871                        mark_buffer_dirty(ibh);
1872                        nilfs_mdt_mark_dirty(ifile);
1873                        spin_lock(&nilfs->ns_inode_lock);
1874                        if (likely(!ii->i_bh))
1875                                ii->i_bh = ibh;
1876                        else
1877                                brelse(ibh);
1878                        goto retry;
1879                }
1880
1881                clear_bit(NILFS_I_QUEUED, &ii->i_state);
1882                set_bit(NILFS_I_BUSY, &ii->i_state);
1883                list_move_tail(&ii->i_dirty, &sci->sc_dirty_files);
1884        }
1885        spin_unlock(&nilfs->ns_inode_lock);
1886
1887        return 0;
1888}
1889
1890static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
1891                                             struct the_nilfs *nilfs)
1892{
1893        struct nilfs_transaction_info *ti = current->journal_info;
1894        struct nilfs_inode_info *ii, *n;
1895
1896        spin_lock(&nilfs->ns_inode_lock);
1897        list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
1898                if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
1899                    test_bit(NILFS_I_DIRTY, &ii->i_state))
1900                        continue;
1901
1902                clear_bit(NILFS_I_BUSY, &ii->i_state);
1903                brelse(ii->i_bh);
1904                ii->i_bh = NULL;
1905                list_move_tail(&ii->i_dirty, &ti->ti_garbage);
1906        }
1907        spin_unlock(&nilfs->ns_inode_lock);
1908}
1909
1910/*
1911 * Main procedure of segment constructor
1912 */
1913static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
1914{
1915        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1916        int err;
1917
1918        sci->sc_stage.scnt = NILFS_ST_INIT;
1919        sci->sc_cno = nilfs->ns_cno;
1920
1921        err = nilfs_segctor_collect_dirty_files(sci, nilfs);
1922        if (unlikely(err))
1923                goto out;
1924
1925        if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
1926                set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1927
1928        if (nilfs_segctor_clean(sci))
1929                goto out;
1930
1931        do {
1932                sci->sc_stage.flags &= ~NILFS_CF_HISTORY_MASK;
1933
1934                err = nilfs_segctor_begin_construction(sci, nilfs);
1935                if (unlikely(err))
1936                        goto out;
1937
1938                /* Update time stamp */
1939                sci->sc_seg_ctime = get_seconds();
1940
1941                err = nilfs_segctor_collect(sci, nilfs, mode);
1942                if (unlikely(err))
1943                        goto failed;
1944
1945                /* Avoid empty segment */
1946                if (sci->sc_stage.scnt == NILFS_ST_DONE &&
1947                    nilfs_segbuf_empty(sci->sc_curseg)) {
1948                        nilfs_segctor_abort_construction(sci, nilfs, 1);
1949                        goto out;
1950                }
1951
1952                err = nilfs_segctor_assign(sci, mode);
1953                if (unlikely(err))
1954                        goto failed;
1955
1956                if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
1957                        nilfs_segctor_fill_in_file_bmap(sci);
1958
1959                if (mode == SC_LSEG_SR &&
1960                    sci->sc_stage.scnt >= NILFS_ST_CPFILE) {
1961                        err = nilfs_segctor_fill_in_checkpoint(sci);
1962                        if (unlikely(err))
1963                                goto failed_to_write;
1964
1965                        nilfs_segctor_fill_in_super_root(sci, nilfs);
1966                }
1967                nilfs_segctor_update_segusage(sci, nilfs->ns_sufile);
1968
1969                /* Write partial segments */
1970                nilfs_segctor_prepare_write(sci);
1971
1972                nilfs_add_checksums_on_logs(&sci->sc_segbufs,
1973                                            nilfs->ns_crc_seed);
1974
1975                err = nilfs_segctor_write(sci, nilfs);
1976                if (unlikely(err))
1977                        goto failed_to_write;
1978
1979                if (sci->sc_stage.scnt == NILFS_ST_DONE ||
1980                    nilfs->ns_blocksize_bits != PAGE_CACHE_SHIFT) {
1981                        /*
1982                         * At this point, we avoid double buffering
1983                         * for blocksize < pagesize because page dirty
1984                         * flag is turned off during write and dirty
1985                         * buffers are not properly collected for
1986                         * pages crossing over segments.
1987                         */
1988                        err = nilfs_segctor_wait(sci);
1989                        if (err)
1990                                goto failed_to_write;
1991                }
1992        } while (sci->sc_stage.scnt != NILFS_ST_DONE);
1993
1994 out:
1995        nilfs_segctor_drop_written_files(sci, nilfs);
1996        return err;
1997
1998 failed_to_write:
1999        if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2000                nilfs_redirty_inodes(&sci->sc_dirty_files);
2001
2002 failed:
2003        if (nilfs_doing_gc())
2004                nilfs_redirty_inodes(&sci->sc_gc_inodes);
2005        nilfs_segctor_abort_construction(sci, nilfs, err);
2006        goto out;
2007}
2008
2009/**
2010 * nilfs_segctor_start_timer - set timer of background write
2011 * @sci: nilfs_sc_info
2012 *
2013 * If the timer has already been set, it ignores the new request.
2014 * This function MUST be called within a section locking the segment
2015 * semaphore.
2016 */
2017static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
2018{
2019        spin_lock(&sci->sc_state_lock);
2020        if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
2021                sci->sc_timer.expires = jiffies + sci->sc_interval;
2022                add_timer(&sci->sc_timer);
2023                sci->sc_state |= NILFS_SEGCTOR_COMMIT;
2024        }
2025        spin_unlock(&sci->sc_state_lock);
2026}
2027
2028static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
2029{
2030        spin_lock(&sci->sc_state_lock);
2031        if (!(sci->sc_flush_request & (1 << bn))) {
2032                unsigned long prev_req = sci->sc_flush_request;
2033
2034                sci->sc_flush_request |= (1 << bn);
2035                if (!prev_req)
2036                        wake_up(&sci->sc_wait_daemon);
2037        }
2038        spin_unlock(&sci->sc_state_lock);
2039}
2040
2041/**
2042 * nilfs_flush_segment - trigger a segment construction for resource control
2043 * @sb: super block
2044 * @ino: inode number of the file to be flushed out.
2045 */
2046void nilfs_flush_segment(struct super_block *sb, ino_t ino)
2047{
2048        struct the_nilfs *nilfs = sb->s_fs_info;
2049        struct nilfs_sc_info *sci = nilfs->ns_writer;
2050
2051        if (!sci || nilfs_doing_construction())
2052                return;
2053        nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
2054                                        /* assign bit 0 to data files */
2055}
2056
2057struct nilfs_segctor_wait_request {
2058        wait_queue_t    wq;
2059        __u32           seq;
2060        int             err;
2061        atomic_t        done;
2062};
2063
2064static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
2065{
2066        struct nilfs_segctor_wait_request wait_req;
2067        int err = 0;
2068
2069        spin_lock(&sci->sc_state_lock);
2070        init_wait(&wait_req.wq);
2071        wait_req.err = 0;
2072        atomic_set(&wait_req.done, 0);
2073        wait_req.seq = ++sci->sc_seq_request;
2074        spin_unlock(&sci->sc_state_lock);
2075
2076        init_waitqueue_entry(&wait_req.wq, current);
2077        add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
2078        set_current_state(TASK_INTERRUPTIBLE);
2079        wake_up(&sci->sc_wait_daemon);
2080
2081        for (;;) {
2082                if (atomic_read(&wait_req.done)) {
2083                        err = wait_req.err;
2084                        break;
2085                }
2086                if (!signal_pending(current)) {
2087                        schedule();
2088                        continue;
2089                }
2090                err = -ERESTARTSYS;
2091                break;
2092        }
2093        finish_wait(&sci->sc_wait_request, &wait_req.wq);
2094        return err;
2095}
2096
2097static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
2098{
2099        struct nilfs_segctor_wait_request *wrq, *n;
2100        unsigned long flags;
2101
2102        spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
2103        list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.task_list,
2104                                 wq.task_list) {
2105                if (!atomic_read(&wrq->done) &&
2106                    nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
2107                        wrq->err = err;
2108                        atomic_set(&wrq->done, 1);
2109                }
2110                if (atomic_read(&wrq->done)) {
2111                        wrq->wq.func(&wrq->wq,
2112                                     TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
2113                                     0, NULL);
2114                }
2115        }
2116        spin_unlock_irqrestore(&sci->sc_wait_request.lock, flags);
2117}
2118
2119/**
2120 * nilfs_construct_segment - construct a logical segment
2121 * @sb: super block
2122 *
2123 * Return Value: On success, 0 is retured. On errors, one of the following
2124 * negative error code is returned.
2125 *
2126 * %-EROFS - Read only filesystem.
2127 *
2128 * %-EIO - I/O error
2129 *
2130 * %-ENOSPC - No space left on device (only in a panic state).
2131 *
2132 * %-ERESTARTSYS - Interrupted.
2133 *
2134 * %-ENOMEM - Insufficient memory available.
2135 */
2136int nilfs_construct_segment(struct super_block *sb)
2137{
2138        struct the_nilfs *nilfs = sb->s_fs_info;
2139        struct nilfs_sc_info *sci = nilfs->ns_writer;
2140        struct nilfs_transaction_info *ti;
2141        int err;
2142
2143        if (!sci)
2144                return -EROFS;
2145
2146        /* A call inside transactions causes a deadlock. */
2147        BUG_ON((ti = current->journal_info) && ti->ti_magic == NILFS_TI_MAGIC);
2148
2149        err = nilfs_segctor_sync(sci);
2150        return err;
2151}
2152
2153/**
2154 * nilfs_construct_dsync_segment - construct a data-only logical segment
2155 * @sb: super block
2156 * @inode: inode whose data blocks should be written out
2157 * @start: start byte offset
2158 * @end: end byte offset (inclusive)
2159 *
2160 * Return Value: On success, 0 is retured. On errors, one of the following
2161 * negative error code is returned.
2162 *
2163 * %-EROFS - Read only filesystem.
2164 *
2165 * %-EIO - I/O error
2166 *
2167 * %-ENOSPC - No space left on device (only in a panic state).
2168 *
2169 * %-ERESTARTSYS - Interrupted.
2170 *
2171 * %-ENOMEM - Insufficient memory available.
2172 */
2173int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
2174                                  loff_t start, loff_t end)
2175{
2176        struct the_nilfs *nilfs = sb->s_fs_info;
2177        struct nilfs_sc_info *sci = nilfs->ns_writer;
2178        struct nilfs_inode_info *ii;
2179        struct nilfs_transaction_info ti;
2180        int err = 0;
2181
2182        if (!sci)
2183                return -EROFS;
2184
2185        nilfs_transaction_lock(sb, &ti, 0);
2186
2187        ii = NILFS_I(inode);
2188        if (test_bit(NILFS_I_INODE_DIRTY, &ii->i_state) ||
2189            nilfs_test_opt(nilfs, STRICT_ORDER) ||
2190            test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2191            nilfs_discontinued(nilfs)) {
2192                nilfs_transaction_unlock(sb);
2193                err = nilfs_segctor_sync(sci);
2194                return err;
2195        }
2196
2197        spin_lock(&nilfs->ns_inode_lock);
2198        if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
2199            !test_bit(NILFS_I_BUSY, &ii->i_state)) {
2200                spin_unlock(&nilfs->ns_inode_lock);
2201                nilfs_transaction_unlock(sb);
2202                return 0;
2203        }
2204        spin_unlock(&nilfs->ns_inode_lock);
2205        sci->sc_dsync_inode = ii;
2206        sci->sc_dsync_start = start;
2207        sci->sc_dsync_end = end;
2208
2209        err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC);
2210
2211        nilfs_transaction_unlock(sb);
2212        return err;
2213}
2214
2215#define FLUSH_FILE_BIT  (0x1) /* data file only */
2216#define FLUSH_DAT_BIT   (1 << NILFS_DAT_INO) /* DAT only */
2217
2218/**
2219 * nilfs_segctor_accept - record accepted sequence count of log-write requests
2220 * @sci: segment constructor object
2221 */
2222static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
2223{
2224        spin_lock(&sci->sc_state_lock);
2225        sci->sc_seq_accepted = sci->sc_seq_request;
2226        spin_unlock(&sci->sc_state_lock);
2227        del_timer_sync(&sci->sc_timer);
2228}
2229
2230/**
2231 * nilfs_segctor_notify - notify the result of request to caller threads
2232 * @sci: segment constructor object
2233 * @mode: mode of log forming
2234 * @err: error code to be notified
2235 */
2236static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
2237{
2238        /* Clear requests (even when the construction failed) */
2239        spin_lock(&sci->sc_state_lock);
2240
2241        if (mode == SC_LSEG_SR) {
2242                sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
2243                sci->sc_seq_done = sci->sc_seq_accepted;
2244                nilfs_segctor_wakeup(sci, err);
2245                sci->sc_flush_request = 0;
2246        } else {
2247                if (mode == SC_FLUSH_FILE)
2248                        sci->sc_flush_request &= ~FLUSH_FILE_BIT;
2249                else if (mode == SC_FLUSH_DAT)
2250                        sci->sc_flush_request &= ~FLUSH_DAT_BIT;
2251
2252                /* re-enable timer if checkpoint creation was not done */
2253                if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2254                    time_before(jiffies, sci->sc_timer.expires))
2255                        add_timer(&sci->sc_timer);
2256        }
2257        spin_unlock(&sci->sc_state_lock);
2258}
2259
2260/**
2261 * nilfs_segctor_construct - form logs and write them to disk
2262 * @sci: segment constructor object
2263 * @mode: mode of log forming
2264 */
2265static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
2266{
2267        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2268        struct nilfs_super_block **sbp;
2269        int err = 0;
2270
2271        nilfs_segctor_accept(sci);
2272
2273        if (nilfs_discontinued(nilfs))
2274                mode = SC_LSEG_SR;
2275        if (!nilfs_segctor_confirm(sci))
2276                err = nilfs_segctor_do_construct(sci, mode);
2277
2278        if (likely(!err)) {
2279                if (mode != SC_FLUSH_DAT)
2280                        atomic_set(&nilfs->ns_ndirtyblks, 0);
2281                if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
2282                    nilfs_discontinued(nilfs)) {
2283                        down_write(&nilfs->ns_sem);
2284                        err = -EIO;
2285                        sbp = nilfs_prepare_super(sci->sc_super,
2286                                                  nilfs_sb_will_flip(nilfs));
2287                        if (likely(sbp)) {
2288                                nilfs_set_log_cursor(sbp[0], nilfs);
2289                                err = nilfs_commit_super(sci->sc_super,
2290                                                         NILFS_SB_COMMIT);
2291                        }
2292                        up_write(&nilfs->ns_sem);
2293                }
2294        }
2295
2296        nilfs_segctor_notify(sci, mode, err);
2297        return err;
2298}
2299
2300static void nilfs_construction_timeout(unsigned long data)
2301{
2302        struct task_struct *p = (struct task_struct *)data;
2303        wake_up_process(p);
2304}
2305
2306static void
2307nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
2308{
2309        struct nilfs_inode_info *ii, *n;
2310
2311        list_for_each_entry_safe(ii, n, head, i_dirty) {
2312                if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
2313                        continue;
2314                list_del_init(&ii->i_dirty);
2315                truncate_inode_pages(&ii->vfs_inode.i_data, 0);
2316                nilfs_btnode_cache_clear(&ii->i_btnode_cache);
2317                iput(&ii->vfs_inode);
2318        }
2319}
2320
2321int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
2322                         void **kbufs)
2323{
2324        struct the_nilfs *nilfs = sb->s_fs_info;
2325        struct nilfs_sc_info *sci = nilfs->ns_writer;
2326        struct nilfs_transaction_info ti;
2327        int err;
2328
2329        if (unlikely(!sci))
2330                return -EROFS;
2331
2332        nilfs_transaction_lock(sb, &ti, 1);
2333
2334        err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
2335        if (unlikely(err))
2336                goto out_unlock;
2337
2338        err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
2339        if (unlikely(err)) {
2340                nilfs_mdt_restore_from_shadow_map(nilfs->ns_dat);
2341                goto out_unlock;
2342        }
2343
2344        sci->sc_freesegs = kbufs[4];
2345        sci->sc_nfreesegs = argv[4].v_nmembs;
2346        list_splice_tail_init(&nilfs->ns_gc_inodes, &sci->sc_gc_inodes);
2347
2348        for (;;) {
2349                err = nilfs_segctor_construct(sci, SC_LSEG_SR);
2350                nilfs_remove_written_gcinodes(nilfs, &sci->sc_gc_inodes);
2351
2352                if (likely(!err))
2353                        break;
2354
2355                nilfs_warning(sb, __func__,
2356                              "segment construction failed. (err=%d)", err);
2357                set_current_state(TASK_INTERRUPTIBLE);
2358                schedule_timeout(sci->sc_interval);
2359        }
2360        if (nilfs_test_opt(nilfs, DISCARD)) {
2361                int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
2362                                                 sci->sc_nfreesegs);
2363                if (ret) {
2364                        printk(KERN_WARNING
2365                               "NILFS warning: error %d on discard request, "
2366                               "turning discards off for the device\n", ret);
2367                        nilfs_clear_opt(nilfs, DISCARD);
2368                }
2369        }
2370
2371 out_unlock:
2372        sci->sc_freesegs = NULL;
2373        sci->sc_nfreesegs = 0;
2374        nilfs_mdt_clear_shadow_map(nilfs->ns_dat);
2375        nilfs_transaction_unlock(sb);
2376        return err;
2377}
2378
2379static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
2380{
2381        struct nilfs_transaction_info ti;
2382
2383        nilfs_transaction_lock(sci->sc_super, &ti, 0);
2384        nilfs_segctor_construct(sci, mode);
2385
2386        /*
2387         * Unclosed segment should be retried.  We do this using sc_timer.
2388         * Timeout of sc_timer will invoke complete construction which leads
2389         * to close the current logical segment.
2390         */
2391        if (test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags))
2392                nilfs_segctor_start_timer(sci);
2393
2394        nilfs_transaction_unlock(sci->sc_super);
2395}
2396
2397static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
2398{
2399        int mode = 0;
2400        int err;
2401
2402        spin_lock(&sci->sc_state_lock);
2403        mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
2404                SC_FLUSH_DAT : SC_FLUSH_FILE;
2405        spin_unlock(&sci->sc_state_lock);
2406
2407        if (mode) {
2408                err = nilfs_segctor_do_construct(sci, mode);
2409
2410                spin_lock(&sci->sc_state_lock);
2411                sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
2412                        ~FLUSH_FILE_BIT : ~FLUSH_DAT_BIT;
2413                spin_unlock(&sci->sc_state_lock);
2414        }
2415        clear_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
2416}
2417
2418static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
2419{
2420        if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2421            time_before(jiffies, sci->sc_lseg_stime + sci->sc_mjcp_freq)) {
2422                if (!(sci->sc_flush_request & ~FLUSH_FILE_BIT))
2423                        return SC_FLUSH_FILE;
2424                else if (!(sci->sc_flush_request & ~FLUSH_DAT_BIT))
2425                        return SC_FLUSH_DAT;
2426        }
2427        return SC_LSEG_SR;
2428}
2429
2430/**
2431 * nilfs_segctor_thread - main loop of the segment constructor thread.
2432 * @arg: pointer to a struct nilfs_sc_info.
2433 *
2434 * nilfs_segctor_thread() initializes a timer and serves as a daemon
2435 * to execute segment constructions.
2436 */
2437static int nilfs_segctor_thread(void *arg)
2438{
2439        struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
2440        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2441        int timeout = 0;
2442
2443        sci->sc_timer.data = (unsigned long)current;
2444        sci->sc_timer.function = nilfs_construction_timeout;
2445
2446        /* start sync. */
2447        sci->sc_task = current;
2448        wake_up(&sci->sc_wait_task); /* for nilfs_segctor_start_thread() */
2449        printk(KERN_INFO
2450               "segctord starting. Construction interval = %lu seconds, "
2451               "CP frequency < %lu seconds\n",
2452               sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
2453
2454        spin_lock(&sci->sc_state_lock);
2455 loop:
2456        for (;;) {
2457                int mode;
2458
2459                if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2460                        goto end_thread;
2461
2462                if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2463                        mode = SC_LSEG_SR;
2464                else if (!sci->sc_flush_request)
2465                        break;
2466                else
2467                        mode = nilfs_segctor_flush_mode(sci);
2468
2469                spin_unlock(&sci->sc_state_lock);
2470                nilfs_segctor_thread_construct(sci, mode);
2471                spin_lock(&sci->sc_state_lock);
2472                timeout = 0;
2473        }
2474
2475
2476        if (freezing(current)) {
2477                spin_unlock(&sci->sc_state_lock);
2478                try_to_freeze();
2479                spin_lock(&sci->sc_state_lock);
2480        } else {
2481                DEFINE_WAIT(wait);
2482                int should_sleep = 1;
2483
2484                prepare_to_wait(&sci->sc_wait_daemon, &wait,
2485                                TASK_INTERRUPTIBLE);
2486
2487                if (sci->sc_seq_request != sci->sc_seq_done)
2488                        should_sleep = 0;
2489                else if (sci->sc_flush_request)
2490                        should_sleep = 0;
2491                else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2492                        should_sleep = time_before(jiffies,
2493                                        sci->sc_timer.expires);
2494
2495                if (should_sleep) {
2496                        spin_unlock(&sci->sc_state_lock);
2497                        schedule();
2498                        spin_lock(&sci->sc_state_lock);
2499                }
2500                finish_wait(&sci->sc_wait_daemon, &wait);
2501                timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2502                           time_after_eq(jiffies, sci->sc_timer.expires));
2503
2504                if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2505                        set_nilfs_discontinued(nilfs);
2506        }
2507        goto loop;
2508
2509 end_thread:
2510        spin_unlock(&sci->sc_state_lock);
2511
2512        /* end sync. */
2513        sci->sc_task = NULL;
2514        wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
2515        return 0;
2516}
2517
2518static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2519{
2520        struct task_struct *t;
2521
2522        t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2523        if (IS_ERR(t)) {
2524                int err = PTR_ERR(t);
2525
2526                printk(KERN_ERR "NILFS: error %d creating segctord thread\n",
2527                       err);
2528                return err;
2529        }
2530        wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2531        return 0;
2532}
2533
2534static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2535        __acquires(&sci->sc_state_lock)
2536        __releases(&sci->sc_state_lock)
2537{
2538        sci->sc_state |= NILFS_SEGCTOR_QUIT;
2539
2540        while (sci->sc_task) {
2541                wake_up(&sci->sc_wait_daemon);
2542                spin_unlock(&sci->sc_state_lock);
2543                wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2544                spin_lock(&sci->sc_state_lock);
2545        }
2546}
2547
2548/*
2549 * Setup & clean-up functions
2550 */
2551static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
2552                                               struct nilfs_root *root)
2553{
2554        struct the_nilfs *nilfs = sb->s_fs_info;
2555        struct nilfs_sc_info *sci;
2556
2557        sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2558        if (!sci)
2559                return NULL;
2560
2561        sci->sc_super = sb;
2562
2563        nilfs_get_root(root);
2564        sci->sc_root = root;
2565
2566        init_waitqueue_head(&sci->sc_wait_request);
2567        init_waitqueue_head(&sci->sc_wait_daemon);
2568        init_waitqueue_head(&sci->sc_wait_task);
2569        spin_lock_init(&sci->sc_state_lock);
2570        INIT_LIST_HEAD(&sci->sc_dirty_files);
2571        INIT_LIST_HEAD(&sci->sc_segbufs);
2572        INIT_LIST_HEAD(&sci->sc_write_logs);
2573        INIT_LIST_HEAD(&sci->sc_gc_inodes);
2574        init_timer(&sci->sc_timer);
2575
2576        sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2577        sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2578        sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2579
2580        if (nilfs->ns_interval)
2581                sci->sc_interval = HZ * nilfs->ns_interval;
2582        if (nilfs->ns_watermark)
2583                sci->sc_watermark = nilfs->ns_watermark;
2584        return sci;
2585}
2586
2587static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2588{
2589        int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2590
2591        /* The segctord thread was stopped and its timer was removed.
2592           But some tasks remain. */
2593        do {
2594                struct nilfs_transaction_info ti;
2595
2596                nilfs_transaction_lock(sci->sc_super, &ti, 0);
2597                ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2598                nilfs_transaction_unlock(sci->sc_super);
2599
2600        } while (ret && retrycount-- > 0);
2601}
2602
2603/**
2604 * nilfs_segctor_destroy - destroy the segment constructor.
2605 * @sci: nilfs_sc_info
2606 *
2607 * nilfs_segctor_destroy() kills the segctord thread and frees
2608 * the nilfs_sc_info struct.
2609 * Caller must hold the segment semaphore.
2610 */
2611static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2612{
2613        struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2614        int flag;
2615
2616        up_write(&nilfs->ns_segctor_sem);
2617
2618        spin_lock(&sci->sc_state_lock);
2619        nilfs_segctor_kill_thread(sci);
2620        flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2621                || sci->sc_seq_request != sci->sc_seq_done);
2622        spin_unlock(&sci->sc_state_lock);
2623
2624        if (flag || !nilfs_segctor_confirm(sci))
2625                nilfs_segctor_write_out(sci);
2626
2627        if (!list_empty(&sci->sc_dirty_files)) {
2628                nilfs_warning(sci->sc_super, __func__,
2629                              "dirty file(s) after the final construction\n");
2630                nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2631        }
2632
2633        WARN_ON(!list_empty(&sci->sc_segbufs));
2634        WARN_ON(!list_empty(&sci->sc_write_logs));
2635
2636        nilfs_put_root(sci->sc_root);
2637
2638        down_write(&nilfs->ns_segctor_sem);
2639
2640        del_timer_sync(&sci->sc_timer);
2641        kfree(sci);
2642}
2643
2644/**
2645 * nilfs_attach_log_writer - attach log writer
2646 * @sb: super block instance
2647 * @root: root object of the current filesystem tree
2648 *
2649 * This allocates a log writer object, initializes it, and starts the
2650 * log writer.
2651 *
2652 * Return Value: On success, 0 is returned. On error, one of the following
2653 * negative error code is returned.
2654 *
2655 * %-ENOMEM - Insufficient memory available.
2656 */
2657int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
2658{
2659        struct the_nilfs *nilfs = sb->s_fs_info;
2660        int err;
2661
2662        if (nilfs->ns_writer) {
2663                /*
2664                 * This happens if the filesystem was remounted
2665                 * read/write after nilfs_error degenerated it into a
2666                 * read-only mount.
2667                 */
2668                nilfs_detach_log_writer(sb);
2669        }
2670
2671        nilfs->ns_writer = nilfs_segctor_new(sb, root);
2672        if (!nilfs->ns_writer)
2673                return -ENOMEM;
2674
2675        err = nilfs_segctor_start_thread(nilfs->ns_writer);
2676        if (err) {
2677                kfree(nilfs->ns_writer);
2678                nilfs->ns_writer = NULL;
2679        }
2680        return err;
2681}
2682
2683/**
2684 * nilfs_detach_log_writer - destroy log writer
2685 * @sb: super block instance
2686 *
2687 * This kills log writer daemon, frees the log writer object, and
2688 * destroys list of dirty files.
2689 */
2690void nilfs_detach_log_writer(struct super_block *sb)
2691{
2692        struct the_nilfs *nilfs = sb->s_fs_info;
2693        LIST_HEAD(garbage_list);
2694
2695        down_write(&nilfs->ns_segctor_sem);
2696        if (nilfs->ns_writer) {
2697                nilfs_segctor_destroy(nilfs->ns_writer);
2698                nilfs->ns_writer = NULL;
2699        }
2700
2701        /* Force to free the list of dirty files */
2702        spin_lock(&nilfs->ns_inode_lock);
2703        if (!list_empty(&nilfs->ns_dirty_files)) {
2704                list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2705                nilfs_warning(sb, __func__,
2706                              "Hit dirty file after stopped log writer\n");
2707        }
2708        spin_unlock(&nilfs->ns_inode_lock);
2709        up_write(&nilfs->ns_segctor_sem);
2710
2711        nilfs_dispose_list(nilfs, &garbage_list, 1);
2712}
2713
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