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 * Written by Ryusuke Konishi.
 
 
 
 
  17 *
  18 */
  19
  20#include <linux/pagemap.h>
  21#include <linux/buffer_head.h>
  22#include <linux/writeback.h>
  23#include <linux/bitops.h>
  24#include <linux/bio.h>
  25#include <linux/completion.h>
  26#include <linux/blkdev.h>
  27#include <linux/backing-dev.h>
  28#include <linux/freezer.h>
  29#include <linux/kthread.h>
  30#include <linux/crc32.h>
  31#include <linux/pagevec.h>
  32#include <linux/slab.h>
  33#include "nilfs.h"
  34#include "btnode.h"
  35#include "page.h"
  36#include "segment.h"
  37#include "sufile.h"
  38#include "cpfile.h"
  39#include "ifile.h"
  40#include "segbuf.h"
  41
  42
  43/*
  44 * Segment constructor
  45 */
  46#define SC_N_INODEVEC	16   /* Size of locally allocated inode vector */
  47
  48#define SC_MAX_SEGDELTA 64   /*
  49			      * Upper limit of the number of segments
  50			      * appended in collection retry loop
  51			      */
  52
  53/* Construction mode */
  54enum {
  55	SC_LSEG_SR = 1,	/* Make a logical segment having a super root */
  56	SC_LSEG_DSYNC,	/*
  57			 * Flush data blocks of a given file and make
  58			 * a logical segment without a super root.
  59			 */
  60	SC_FLUSH_FILE,	/*
  61			 * Flush data files, leads to segment writes without
  62			 * creating a checkpoint.
  63			 */
  64	SC_FLUSH_DAT,	/*
  65			 * Flush DAT file.  This also creates segments
  66			 * without a checkpoint.
  67			 */
  68};
  69
  70/* Stage numbers of dirty block collection */
  71enum {
  72	NILFS_ST_INIT = 0,
  73	NILFS_ST_GC,		/* Collecting dirty blocks for GC */
  74	NILFS_ST_FILE,
  75	NILFS_ST_IFILE,
  76	NILFS_ST_CPFILE,
  77	NILFS_ST_SUFILE,
  78	NILFS_ST_DAT,
  79	NILFS_ST_SR,		/* Super root */
  80	NILFS_ST_DSYNC,		/* Data sync blocks */
  81	NILFS_ST_DONE,
  82};
  83
  84#define CREATE_TRACE_POINTS
  85#include <trace/events/nilfs2.h>
  86
  87/*
  88 * nilfs_sc_cstage_inc(), nilfs_sc_cstage_set(), nilfs_sc_cstage_get() are
  89 * wrapper functions of stage count (nilfs_sc_info->sc_stage.scnt). Users of
  90 * the variable must use them because transition of stage count must involve
  91 * trace events (trace_nilfs2_collection_stage_transition).
  92 *
  93 * nilfs_sc_cstage_get() isn't required for the above purpose because it doesn't
  94 * produce tracepoint events. It is provided just for making the intention
  95 * clear.
  96 */
  97static inline void nilfs_sc_cstage_inc(struct nilfs_sc_info *sci)
  98{
  99	sci->sc_stage.scnt++;
 100	trace_nilfs2_collection_stage_transition(sci);
 101}
 102
 103static inline void nilfs_sc_cstage_set(struct nilfs_sc_info *sci, int next_scnt)
 104{
 105	sci->sc_stage.scnt = next_scnt;
 106	trace_nilfs2_collection_stage_transition(sci);
 107}
 108
 109static inline int nilfs_sc_cstage_get(struct nilfs_sc_info *sci)
 110{
 111	return sci->sc_stage.scnt;
 112}
 113
 114/* State flags of collection */
 115#define NILFS_CF_NODE		0x0001	/* Collecting node blocks */
 116#define NILFS_CF_IFILE_STARTED	0x0002	/* IFILE stage has started */
 117#define NILFS_CF_SUFREED	0x0004	/* segment usages has been freed */
 118#define NILFS_CF_HISTORY_MASK	(NILFS_CF_IFILE_STARTED | NILFS_CF_SUFREED)
 119
 120/* Operations depending on the construction mode and file type */
 121struct nilfs_sc_operations {
 122	int (*collect_data)(struct nilfs_sc_info *, struct buffer_head *,
 123			    struct inode *);
 124	int (*collect_node)(struct nilfs_sc_info *, struct buffer_head *,
 125			    struct inode *);
 126	int (*collect_bmap)(struct nilfs_sc_info *, struct buffer_head *,
 127			    struct inode *);
 128	void (*write_data_binfo)(struct nilfs_sc_info *,
 129				 struct nilfs_segsum_pointer *,
 130				 union nilfs_binfo *);
 131	void (*write_node_binfo)(struct nilfs_sc_info *,
 132				 struct nilfs_segsum_pointer *,
 133				 union nilfs_binfo *);
 134};
 135
 136/*
 137 * Other definitions
 138 */
 139static void nilfs_segctor_start_timer(struct nilfs_sc_info *);
 140static void nilfs_segctor_do_flush(struct nilfs_sc_info *, int);
 141static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *);
 142static void nilfs_dispose_list(struct the_nilfs *, struct list_head *, int);
 143
 144#define nilfs_cnt32_gt(a, b)   \
 145	(typecheck(__u32, a) && typecheck(__u32, b) && \
 146	 ((__s32)(b) - (__s32)(a) < 0))
 147#define nilfs_cnt32_ge(a, b)   \
 148	(typecheck(__u32, a) && typecheck(__u32, b) && \
 149	 ((__s32)(a) - (__s32)(b) >= 0))
 150#define nilfs_cnt32_lt(a, b)  nilfs_cnt32_gt(b, a)
 151#define nilfs_cnt32_le(a, b)  nilfs_cnt32_ge(b, a)
 152
 153static int nilfs_prepare_segment_lock(struct super_block *sb,
 154				      struct nilfs_transaction_info *ti)
 155{
 156	struct nilfs_transaction_info *cur_ti = current->journal_info;
 157	void *save = NULL;
 158
 159	if (cur_ti) {
 160		if (cur_ti->ti_magic == NILFS_TI_MAGIC)
 161			return ++cur_ti->ti_count;
 162
 163		/*
 164		 * If journal_info field is occupied by other FS,
 165		 * it is saved and will be restored on
 166		 * nilfs_transaction_commit().
 167		 */
 168		nilfs_msg(sb, KERN_WARNING, "journal info from a different FS");
 169		save = current->journal_info;
 
 
 
 170	}
 171	if (!ti) {
 172		ti = kmem_cache_alloc(nilfs_transaction_cachep, GFP_NOFS);
 173		if (!ti)
 174			return -ENOMEM;
 175		ti->ti_flags = NILFS_TI_DYNAMIC_ALLOC;
 176	} else {
 177		ti->ti_flags = 0;
 178	}
 179	ti->ti_count = 0;
 180	ti->ti_save = save;
 181	ti->ti_magic = NILFS_TI_MAGIC;
 182	current->journal_info = ti;
 183	return 0;
 184}
 185
 186/**
 187 * nilfs_transaction_begin - start indivisible file operations.
 188 * @sb: super block
 189 * @ti: nilfs_transaction_info
 190 * @vacancy_check: flags for vacancy rate checks
 191 *
 192 * nilfs_transaction_begin() acquires a reader/writer semaphore, called
 193 * the segment semaphore, to make a segment construction and write tasks
 194 * exclusive.  The function is used with nilfs_transaction_commit() in pairs.
 195 * The region enclosed by these two functions can be nested.  To avoid a
 196 * deadlock, the semaphore is only acquired or released in the outermost call.
 197 *
 198 * This function allocates a nilfs_transaction_info struct to keep context
 199 * information on it.  It is initialized and hooked onto the current task in
 200 * the outermost call.  If a pre-allocated struct is given to @ti, it is used
 201 * instead; otherwise a new struct is assigned from a slab.
 202 *
 203 * When @vacancy_check flag is set, this function will check the amount of
 204 * free space, and will wait for the GC to reclaim disk space if low capacity.
 205 *
 206 * Return Value: On success, 0 is returned. On error, one of the following
 207 * negative error code is returned.
 208 *
 209 * %-ENOMEM - Insufficient memory available.
 210 *
 211 * %-ENOSPC - No space left on device
 212 */
 213int nilfs_transaction_begin(struct super_block *sb,
 214			    struct nilfs_transaction_info *ti,
 215			    int vacancy_check)
 216{
 217	struct the_nilfs *nilfs;
 218	int ret = nilfs_prepare_segment_lock(sb, ti);
 219	struct nilfs_transaction_info *trace_ti;
 220
 221	if (unlikely(ret < 0))
 222		return ret;
 223	if (ret > 0) {
 224		trace_ti = current->journal_info;
 225
 226		trace_nilfs2_transaction_transition(sb, trace_ti,
 227				    trace_ti->ti_count, trace_ti->ti_flags,
 228				    TRACE_NILFS2_TRANSACTION_BEGIN);
 229		return 0;
 230	}
 231
 232	sb_start_intwrite(sb);
 233
 234	nilfs = sb->s_fs_info;
 235	down_read(&nilfs->ns_segctor_sem);
 236	if (vacancy_check && nilfs_near_disk_full(nilfs)) {
 237		up_read(&nilfs->ns_segctor_sem);
 238		ret = -ENOSPC;
 239		goto failed;
 240	}
 241
 242	trace_ti = current->journal_info;
 243	trace_nilfs2_transaction_transition(sb, trace_ti, trace_ti->ti_count,
 244					    trace_ti->ti_flags,
 245					    TRACE_NILFS2_TRANSACTION_BEGIN);
 246	return 0;
 247
 248 failed:
 249	ti = current->journal_info;
 250	current->journal_info = ti->ti_save;
 251	if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 252		kmem_cache_free(nilfs_transaction_cachep, ti);
 253	sb_end_intwrite(sb);
 254	return ret;
 255}
 256
 257/**
 258 * nilfs_transaction_commit - commit indivisible file operations.
 259 * @sb: super block
 260 *
 261 * nilfs_transaction_commit() releases the read semaphore which is
 262 * acquired by nilfs_transaction_begin(). This is only performed
 263 * in outermost call of this function.  If a commit flag is set,
 264 * nilfs_transaction_commit() sets a timer to start the segment
 265 * constructor.  If a sync flag is set, it starts construction
 266 * directly.
 267 */
 268int nilfs_transaction_commit(struct super_block *sb)
 269{
 270	struct nilfs_transaction_info *ti = current->journal_info;
 271	struct the_nilfs *nilfs = sb->s_fs_info;
 272	int err = 0;
 273
 274	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 275	ti->ti_flags |= NILFS_TI_COMMIT;
 276	if (ti->ti_count > 0) {
 277		ti->ti_count--;
 278		trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 279			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
 280		return 0;
 281	}
 282	if (nilfs->ns_writer) {
 283		struct nilfs_sc_info *sci = nilfs->ns_writer;
 284
 285		if (ti->ti_flags & NILFS_TI_COMMIT)
 286			nilfs_segctor_start_timer(sci);
 287		if (atomic_read(&nilfs->ns_ndirtyblks) > sci->sc_watermark)
 288			nilfs_segctor_do_flush(sci, 0);
 289	}
 290	up_read(&nilfs->ns_segctor_sem);
 291	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 292			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
 293
 294	current->journal_info = ti->ti_save;
 295
 296	if (ti->ti_flags & NILFS_TI_SYNC)
 297		err = nilfs_construct_segment(sb);
 298	if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 299		kmem_cache_free(nilfs_transaction_cachep, ti);
 300	sb_end_intwrite(sb);
 301	return err;
 302}
 303
 304void nilfs_transaction_abort(struct super_block *sb)
 305{
 306	struct nilfs_transaction_info *ti = current->journal_info;
 307	struct the_nilfs *nilfs = sb->s_fs_info;
 308
 309	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 310	if (ti->ti_count > 0) {
 311		ti->ti_count--;
 312		trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 313			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
 314		return;
 315	}
 316	up_read(&nilfs->ns_segctor_sem);
 317
 318	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 319		    ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
 320
 321	current->journal_info = ti->ti_save;
 322	if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 323		kmem_cache_free(nilfs_transaction_cachep, ti);
 324	sb_end_intwrite(sb);
 325}
 326
 327void nilfs_relax_pressure_in_lock(struct super_block *sb)
 328{
 329	struct the_nilfs *nilfs = sb->s_fs_info;
 330	struct nilfs_sc_info *sci = nilfs->ns_writer;
 331
 332	if (!sci || !sci->sc_flush_request)
 333		return;
 334
 335	set_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
 336	up_read(&nilfs->ns_segctor_sem);
 337
 338	down_write(&nilfs->ns_segctor_sem);
 339	if (sci->sc_flush_request &&
 340	    test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags)) {
 341		struct nilfs_transaction_info *ti = current->journal_info;
 342
 343		ti->ti_flags |= NILFS_TI_WRITER;
 344		nilfs_segctor_do_immediate_flush(sci);
 345		ti->ti_flags &= ~NILFS_TI_WRITER;
 346	}
 347	downgrade_write(&nilfs->ns_segctor_sem);
 348}
 349
 350static void nilfs_transaction_lock(struct super_block *sb,
 351				   struct nilfs_transaction_info *ti,
 352				   int gcflag)
 353{
 354	struct nilfs_transaction_info *cur_ti = current->journal_info;
 355	struct the_nilfs *nilfs = sb->s_fs_info;
 356	struct nilfs_sc_info *sci = nilfs->ns_writer;
 357
 358	WARN_ON(cur_ti);
 359	ti->ti_flags = NILFS_TI_WRITER;
 360	ti->ti_count = 0;
 361	ti->ti_save = cur_ti;
 362	ti->ti_magic = NILFS_TI_MAGIC;
 
 363	current->journal_info = ti;
 364
 365	for (;;) {
 366		trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 367			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_TRYLOCK);
 368
 369		down_write(&nilfs->ns_segctor_sem);
 370		if (!test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags))
 371			break;
 372
 373		nilfs_segctor_do_immediate_flush(sci);
 374
 375		up_write(&nilfs->ns_segctor_sem);
 376		cond_resched();
 377	}
 378	if (gcflag)
 379		ti->ti_flags |= NILFS_TI_GC;
 380
 381	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 382			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_LOCK);
 383}
 384
 385static void nilfs_transaction_unlock(struct super_block *sb)
 386{
 387	struct nilfs_transaction_info *ti = current->journal_info;
 388	struct the_nilfs *nilfs = sb->s_fs_info;
 389
 390	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 391	BUG_ON(ti->ti_count > 0);
 392
 393	up_write(&nilfs->ns_segctor_sem);
 394	current->journal_info = ti->ti_save;
 395
 396	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 397			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_UNLOCK);
 398}
 399
 400static void *nilfs_segctor_map_segsum_entry(struct nilfs_sc_info *sci,
 401					    struct nilfs_segsum_pointer *ssp,
 402					    unsigned int bytes)
 403{
 404	struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 405	unsigned int blocksize = sci->sc_super->s_blocksize;
 406	void *p;
 407
 408	if (unlikely(ssp->offset + bytes > blocksize)) {
 409		ssp->offset = 0;
 410		BUG_ON(NILFS_SEGBUF_BH_IS_LAST(ssp->bh,
 411					       &segbuf->sb_segsum_buffers));
 412		ssp->bh = NILFS_SEGBUF_NEXT_BH(ssp->bh);
 413	}
 414	p = ssp->bh->b_data + ssp->offset;
 415	ssp->offset += bytes;
 416	return p;
 417}
 418
 419/**
 420 * nilfs_segctor_reset_segment_buffer - reset the current segment buffer
 421 * @sci: nilfs_sc_info
 422 */
 423static int nilfs_segctor_reset_segment_buffer(struct nilfs_sc_info *sci)
 424{
 425	struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 426	struct buffer_head *sumbh;
 427	unsigned int sumbytes;
 428	unsigned int flags = 0;
 429	int err;
 430
 431	if (nilfs_doing_gc())
 432		flags = NILFS_SS_GC;
 433	err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime, sci->sc_cno);
 434	if (unlikely(err))
 435		return err;
 436
 437	sumbh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
 438	sumbytes = segbuf->sb_sum.sumbytes;
 439	sci->sc_finfo_ptr.bh = sumbh;  sci->sc_finfo_ptr.offset = sumbytes;
 440	sci->sc_binfo_ptr.bh = sumbh;  sci->sc_binfo_ptr.offset = sumbytes;
 441	sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 442	return 0;
 443}
 444
 445static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
 446{
 447	sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
 448	if (NILFS_SEGBUF_IS_LAST(sci->sc_curseg, &sci->sc_segbufs))
 449		return -E2BIG; /*
 450				* The current segment is filled up
 451				* (internal code)
 452				*/
 453	sci->sc_curseg = NILFS_NEXT_SEGBUF(sci->sc_curseg);
 454	return nilfs_segctor_reset_segment_buffer(sci);
 455}
 456
 457static int nilfs_segctor_add_super_root(struct nilfs_sc_info *sci)
 458{
 459	struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 460	int err;
 461
 462	if (segbuf->sb_sum.nblocks >= segbuf->sb_rest_blocks) {
 463		err = nilfs_segctor_feed_segment(sci);
 464		if (err)
 465			return err;
 466		segbuf = sci->sc_curseg;
 467	}
 468	err = nilfs_segbuf_extend_payload(segbuf, &segbuf->sb_super_root);
 469	if (likely(!err))
 470		segbuf->sb_sum.flags |= NILFS_SS_SR;
 471	return err;
 472}
 473
 474/*
 475 * Functions for making segment summary and payloads
 476 */
 477static int nilfs_segctor_segsum_block_required(
 478	struct nilfs_sc_info *sci, const struct nilfs_segsum_pointer *ssp,
 479	unsigned int binfo_size)
 480{
 481	unsigned int blocksize = sci->sc_super->s_blocksize;
 482	/* Size of finfo and binfo is enough small against blocksize */
 483
 484	return ssp->offset + binfo_size +
 485		(!sci->sc_blk_cnt ? sizeof(struct nilfs_finfo) : 0) >
 486		blocksize;
 487}
 488
 489static void nilfs_segctor_begin_finfo(struct nilfs_sc_info *sci,
 490				      struct inode *inode)
 491{
 492	sci->sc_curseg->sb_sum.nfinfo++;
 493	sci->sc_binfo_ptr = sci->sc_finfo_ptr;
 494	nilfs_segctor_map_segsum_entry(
 495		sci, &sci->sc_binfo_ptr, sizeof(struct nilfs_finfo));
 496
 497	if (NILFS_I(inode)->i_root &&
 498	    !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 499		set_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
 500	/* skip finfo */
 501}
 502
 503static void nilfs_segctor_end_finfo(struct nilfs_sc_info *sci,
 504				    struct inode *inode)
 505{
 506	struct nilfs_finfo *finfo;
 507	struct nilfs_inode_info *ii;
 508	struct nilfs_segment_buffer *segbuf;
 509	__u64 cno;
 510
 511	if (sci->sc_blk_cnt == 0)
 512		return;
 513
 514	ii = NILFS_I(inode);
 515
 516	if (test_bit(NILFS_I_GCINODE, &ii->i_state))
 517		cno = ii->i_cno;
 518	else if (NILFS_ROOT_METADATA_FILE(inode->i_ino))
 519		cno = 0;
 520	else
 521		cno = sci->sc_cno;
 522
 523	finfo = nilfs_segctor_map_segsum_entry(sci, &sci->sc_finfo_ptr,
 524						 sizeof(*finfo));
 525	finfo->fi_ino = cpu_to_le64(inode->i_ino);
 526	finfo->fi_nblocks = cpu_to_le32(sci->sc_blk_cnt);
 527	finfo->fi_ndatablk = cpu_to_le32(sci->sc_datablk_cnt);
 528	finfo->fi_cno = cpu_to_le64(cno);
 529
 530	segbuf = sci->sc_curseg;
 531	segbuf->sb_sum.sumbytes = sci->sc_binfo_ptr.offset +
 532		sci->sc_super->s_blocksize * (segbuf->sb_sum.nsumblk - 1);
 533	sci->sc_finfo_ptr = sci->sc_binfo_ptr;
 534	sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 535}
 536
 537static int nilfs_segctor_add_file_block(struct nilfs_sc_info *sci,
 538					struct buffer_head *bh,
 539					struct inode *inode,
 540					unsigned int binfo_size)
 541{
 542	struct nilfs_segment_buffer *segbuf;
 543	int required, err = 0;
 544
 545 retry:
 546	segbuf = sci->sc_curseg;
 547	required = nilfs_segctor_segsum_block_required(
 548		sci, &sci->sc_binfo_ptr, binfo_size);
 549	if (segbuf->sb_sum.nblocks + required + 1 > segbuf->sb_rest_blocks) {
 550		nilfs_segctor_end_finfo(sci, inode);
 551		err = nilfs_segctor_feed_segment(sci);
 552		if (err)
 553			return err;
 554		goto retry;
 555	}
 556	if (unlikely(required)) {
 557		err = nilfs_segbuf_extend_segsum(segbuf);
 558		if (unlikely(err))
 559			goto failed;
 560	}
 561	if (sci->sc_blk_cnt == 0)
 562		nilfs_segctor_begin_finfo(sci, inode);
 563
 564	nilfs_segctor_map_segsum_entry(sci, &sci->sc_binfo_ptr, binfo_size);
 565	/* Substitution to vblocknr is delayed until update_blocknr() */
 566	nilfs_segbuf_add_file_buffer(segbuf, bh);
 567	sci->sc_blk_cnt++;
 568 failed:
 569	return err;
 570}
 571
 572/*
 573 * Callback functions that enumerate, mark, and collect dirty blocks
 574 */
 575static int nilfs_collect_file_data(struct nilfs_sc_info *sci,
 576				   struct buffer_head *bh, struct inode *inode)
 577{
 578	int err;
 579
 580	err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 581	if (err < 0)
 582		return err;
 583
 584	err = nilfs_segctor_add_file_block(sci, bh, inode,
 585					   sizeof(struct nilfs_binfo_v));
 586	if (!err)
 587		sci->sc_datablk_cnt++;
 588	return err;
 589}
 590
 591static int nilfs_collect_file_node(struct nilfs_sc_info *sci,
 592				   struct buffer_head *bh,
 593				   struct inode *inode)
 594{
 595	return nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 596}
 597
 598static int nilfs_collect_file_bmap(struct nilfs_sc_info *sci,
 599				   struct buffer_head *bh,
 600				   struct inode *inode)
 601{
 602	WARN_ON(!buffer_dirty(bh));
 603	return nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 604}
 605
 606static void nilfs_write_file_data_binfo(struct nilfs_sc_info *sci,
 607					struct nilfs_segsum_pointer *ssp,
 608					union nilfs_binfo *binfo)
 609{
 610	struct nilfs_binfo_v *binfo_v = nilfs_segctor_map_segsum_entry(
 611		sci, ssp, sizeof(*binfo_v));
 612	*binfo_v = binfo->bi_v;
 613}
 614
 615static void nilfs_write_file_node_binfo(struct nilfs_sc_info *sci,
 616					struct nilfs_segsum_pointer *ssp,
 617					union nilfs_binfo *binfo)
 618{
 619	__le64 *vblocknr = nilfs_segctor_map_segsum_entry(
 620		sci, ssp, sizeof(*vblocknr));
 621	*vblocknr = binfo->bi_v.bi_vblocknr;
 622}
 623
 624static const struct nilfs_sc_operations nilfs_sc_file_ops = {
 625	.collect_data = nilfs_collect_file_data,
 626	.collect_node = nilfs_collect_file_node,
 627	.collect_bmap = nilfs_collect_file_bmap,
 628	.write_data_binfo = nilfs_write_file_data_binfo,
 629	.write_node_binfo = nilfs_write_file_node_binfo,
 630};
 631
 632static int nilfs_collect_dat_data(struct nilfs_sc_info *sci,
 633				  struct buffer_head *bh, struct inode *inode)
 634{
 635	int err;
 636
 637	err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 638	if (err < 0)
 639		return err;
 640
 641	err = nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 642	if (!err)
 643		sci->sc_datablk_cnt++;
 644	return err;
 645}
 646
 647static int nilfs_collect_dat_bmap(struct nilfs_sc_info *sci,
 648				  struct buffer_head *bh, struct inode *inode)
 649{
 650	WARN_ON(!buffer_dirty(bh));
 651	return nilfs_segctor_add_file_block(sci, bh, inode,
 652					    sizeof(struct nilfs_binfo_dat));
 653}
 654
 655static void nilfs_write_dat_data_binfo(struct nilfs_sc_info *sci,
 656				       struct nilfs_segsum_pointer *ssp,
 657				       union nilfs_binfo *binfo)
 658{
 659	__le64 *blkoff = nilfs_segctor_map_segsum_entry(sci, ssp,
 660							  sizeof(*blkoff));
 661	*blkoff = binfo->bi_dat.bi_blkoff;
 662}
 663
 664static void nilfs_write_dat_node_binfo(struct nilfs_sc_info *sci,
 665				       struct nilfs_segsum_pointer *ssp,
 666				       union nilfs_binfo *binfo)
 667{
 668	struct nilfs_binfo_dat *binfo_dat =
 669		nilfs_segctor_map_segsum_entry(sci, ssp, sizeof(*binfo_dat));
 670	*binfo_dat = binfo->bi_dat;
 671}
 672
 673static const struct nilfs_sc_operations nilfs_sc_dat_ops = {
 674	.collect_data = nilfs_collect_dat_data,
 675	.collect_node = nilfs_collect_file_node,
 676	.collect_bmap = nilfs_collect_dat_bmap,
 677	.write_data_binfo = nilfs_write_dat_data_binfo,
 678	.write_node_binfo = nilfs_write_dat_node_binfo,
 679};
 680
 681static const struct nilfs_sc_operations nilfs_sc_dsync_ops = {
 682	.collect_data = nilfs_collect_file_data,
 683	.collect_node = NULL,
 684	.collect_bmap = NULL,
 685	.write_data_binfo = nilfs_write_file_data_binfo,
 686	.write_node_binfo = NULL,
 687};
 688
 689static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode,
 690					      struct list_head *listp,
 691					      size_t nlimit,
 692					      loff_t start, loff_t end)
 693{
 694	struct address_space *mapping = inode->i_mapping;
 695	struct pagevec pvec;
 696	pgoff_t index = 0, last = ULONG_MAX;
 697	size_t ndirties = 0;
 698	int i;
 699
 700	if (unlikely(start != 0 || end != LLONG_MAX)) {
 701		/*
 702		 * A valid range is given for sync-ing data pages. The
 703		 * range is rounded to per-page; extra dirty buffers
 704		 * may be included if blocksize < pagesize.
 705		 */
 706		index = start >> PAGE_SHIFT;
 707		last = end >> PAGE_SHIFT;
 708	}
 709	pagevec_init(&pvec, 0);
 710 repeat:
 711	if (unlikely(index > last) ||
 712	    !pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
 713				min_t(pgoff_t, last - index,
 714				      PAGEVEC_SIZE - 1) + 1))
 715		return ndirties;
 716
 717	for (i = 0; i < pagevec_count(&pvec); i++) {
 718		struct buffer_head *bh, *head;
 719		struct page *page = pvec.pages[i];
 720
 721		if (unlikely(page->index > last))
 722			break;
 723
 724		lock_page(page);
 725		if (!page_has_buffers(page))
 726			create_empty_buffers(page, 1 << inode->i_blkbits, 0);
 727		unlock_page(page);
 728
 729		bh = head = page_buffers(page);
 730		do {
 731			if (!buffer_dirty(bh) || buffer_async_write(bh))
 732				continue;
 733			get_bh(bh);
 734			list_add_tail(&bh->b_assoc_buffers, listp);
 735			ndirties++;
 736			if (unlikely(ndirties >= nlimit)) {
 737				pagevec_release(&pvec);
 738				cond_resched();
 739				return ndirties;
 740			}
 741		} while (bh = bh->b_this_page, bh != head);
 742	}
 743	pagevec_release(&pvec);
 744	cond_resched();
 745	goto repeat;
 746}
 747
 748static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
 749					    struct list_head *listp)
 750{
 751	struct nilfs_inode_info *ii = NILFS_I(inode);
 752	struct address_space *mapping = &ii->i_btnode_cache;
 753	struct pagevec pvec;
 754	struct buffer_head *bh, *head;
 755	unsigned int i;
 756	pgoff_t index = 0;
 757
 758	pagevec_init(&pvec, 0);
 759
 760	while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
 761				  PAGEVEC_SIZE)) {
 762		for (i = 0; i < pagevec_count(&pvec); i++) {
 763			bh = head = page_buffers(pvec.pages[i]);
 764			do {
 765				if (buffer_dirty(bh) &&
 766						!buffer_async_write(bh)) {
 767					get_bh(bh);
 768					list_add_tail(&bh->b_assoc_buffers,
 769						      listp);
 770				}
 771				bh = bh->b_this_page;
 772			} while (bh != head);
 773		}
 774		pagevec_release(&pvec);
 775		cond_resched();
 776	}
 777}
 778
 779static void nilfs_dispose_list(struct the_nilfs *nilfs,
 780			       struct list_head *head, int force)
 781{
 782	struct nilfs_inode_info *ii, *n;
 783	struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
 784	unsigned int nv = 0;
 785
 786	while (!list_empty(head)) {
 787		spin_lock(&nilfs->ns_inode_lock);
 788		list_for_each_entry_safe(ii, n, head, i_dirty) {
 789			list_del_init(&ii->i_dirty);
 790			if (force) {
 791				if (unlikely(ii->i_bh)) {
 792					brelse(ii->i_bh);
 793					ii->i_bh = NULL;
 794				}
 795			} else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
 796				set_bit(NILFS_I_QUEUED, &ii->i_state);
 797				list_add_tail(&ii->i_dirty,
 798					      &nilfs->ns_dirty_files);
 799				continue;
 800			}
 801			ivec[nv++] = ii;
 802			if (nv == SC_N_INODEVEC)
 803				break;
 804		}
 805		spin_unlock(&nilfs->ns_inode_lock);
 806
 807		for (pii = ivec; nv > 0; pii++, nv--)
 808			iput(&(*pii)->vfs_inode);
 809	}
 810}
 811
 812static void nilfs_iput_work_func(struct work_struct *work)
 813{
 814	struct nilfs_sc_info *sci = container_of(work, struct nilfs_sc_info,
 815						 sc_iput_work);
 816	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 817
 818	nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 0);
 819}
 820
 821static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
 822				     struct nilfs_root *root)
 823{
 824	int ret = 0;
 825
 826	if (nilfs_mdt_fetch_dirty(root->ifile))
 827		ret++;
 828	if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
 829		ret++;
 830	if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
 831		ret++;
 832	if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
 833		ret++;
 834	return ret;
 835}
 836
 837static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 838{
 839	return list_empty(&sci->sc_dirty_files) &&
 840		!test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
 841		sci->sc_nfreesegs == 0 &&
 842		(!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
 843}
 844
 845static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 846{
 847	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 848	int ret = 0;
 849
 850	if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
 851		set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
 852
 853	spin_lock(&nilfs->ns_inode_lock);
 854	if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
 855		ret++;
 856
 857	spin_unlock(&nilfs->ns_inode_lock);
 858	return ret;
 859}
 860
 861static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 862{
 863	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 864
 865	nilfs_mdt_clear_dirty(sci->sc_root->ifile);
 866	nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
 867	nilfs_mdt_clear_dirty(nilfs->ns_sufile);
 868	nilfs_mdt_clear_dirty(nilfs->ns_dat);
 869}
 870
 871static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
 872{
 873	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 874	struct buffer_head *bh_cp;
 875	struct nilfs_checkpoint *raw_cp;
 876	int err;
 877
 878	/* XXX: this interface will be changed */
 879	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 1,
 880					  &raw_cp, &bh_cp);
 881	if (likely(!err)) {
 882		/*
 883		 * The following code is duplicated with cpfile.  But, it is
 884		 * needed to collect the checkpoint even if it was not newly
 885		 * created.
 886		 */
 887		mark_buffer_dirty(bh_cp);
 888		nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
 889		nilfs_cpfile_put_checkpoint(
 890			nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 891	} else
 892		WARN_ON(err == -EINVAL || err == -ENOENT);
 893
 894	return err;
 895}
 896
 897static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
 898{
 899	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 900	struct buffer_head *bh_cp;
 901	struct nilfs_checkpoint *raw_cp;
 902	int err;
 903
 904	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
 905					  &raw_cp, &bh_cp);
 906	if (unlikely(err)) {
 907		WARN_ON(err == -EINVAL || err == -ENOENT);
 908		goto failed_ibh;
 909	}
 910	raw_cp->cp_snapshot_list.ssl_next = 0;
 911	raw_cp->cp_snapshot_list.ssl_prev = 0;
 912	raw_cp->cp_inodes_count =
 913		cpu_to_le64(atomic64_read(&sci->sc_root->inodes_count));
 914	raw_cp->cp_blocks_count =
 915		cpu_to_le64(atomic64_read(&sci->sc_root->blocks_count));
 916	raw_cp->cp_nblk_inc =
 917		cpu_to_le64(sci->sc_nblk_inc + sci->sc_nblk_this_inc);
 918	raw_cp->cp_create = cpu_to_le64(sci->sc_seg_ctime);
 919	raw_cp->cp_cno = cpu_to_le64(nilfs->ns_cno);
 920
 921	if (test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 922		nilfs_checkpoint_clear_minor(raw_cp);
 923	else
 924		nilfs_checkpoint_set_minor(raw_cp);
 925
 926	nilfs_write_inode_common(sci->sc_root->ifile,
 927				 &raw_cp->cp_ifile_inode, 1);
 928	nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 929	return 0;
 930
 931 failed_ibh:
 932	return err;
 933}
 934
 935static void nilfs_fill_in_file_bmap(struct inode *ifile,
 936				    struct nilfs_inode_info *ii)
 937
 938{
 939	struct buffer_head *ibh;
 940	struct nilfs_inode *raw_inode;
 941
 942	if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
 943		ibh = ii->i_bh;
 944		BUG_ON(!ibh);
 945		raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
 946						  ibh);
 947		nilfs_bmap_write(ii->i_bmap, raw_inode);
 948		nilfs_ifile_unmap_inode(ifile, ii->vfs_inode.i_ino, ibh);
 949	}
 950}
 951
 952static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
 953{
 954	struct nilfs_inode_info *ii;
 955
 956	list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
 957		nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
 958		set_bit(NILFS_I_COLLECTED, &ii->i_state);
 959	}
 960}
 961
 962static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 963					     struct the_nilfs *nilfs)
 964{
 965	struct buffer_head *bh_sr;
 966	struct nilfs_super_root *raw_sr;
 967	unsigned int isz, srsz;
 968
 969	bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
 970	raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 971	isz = nilfs->ns_inode_size;
 972	srsz = NILFS_SR_BYTES(isz);
 973
 974	raw_sr->sr_bytes = cpu_to_le16(srsz);
 975	raw_sr->sr_nongc_ctime
 976		= cpu_to_le64(nilfs_doing_gc() ?
 977			      nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
 978	raw_sr->sr_flags = 0;
 979
 980	nilfs_write_inode_common(nilfs->ns_dat, (void *)raw_sr +
 981				 NILFS_SR_DAT_OFFSET(isz), 1);
 982	nilfs_write_inode_common(nilfs->ns_cpfile, (void *)raw_sr +
 983				 NILFS_SR_CPFILE_OFFSET(isz), 1);
 984	nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
 985				 NILFS_SR_SUFILE_OFFSET(isz), 1);
 986	memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
 987}
 988
 989static void nilfs_redirty_inodes(struct list_head *head)
 990{
 991	struct nilfs_inode_info *ii;
 992
 993	list_for_each_entry(ii, head, i_dirty) {
 994		if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
 995			clear_bit(NILFS_I_COLLECTED, &ii->i_state);
 996	}
 997}
 998
 999static void nilfs_drop_collected_inodes(struct list_head *head)
1000{
1001	struct nilfs_inode_info *ii;
1002
1003	list_for_each_entry(ii, head, i_dirty) {
1004		if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
1005			continue;
1006
1007		clear_bit(NILFS_I_INODE_SYNC, &ii->i_state);
1008		set_bit(NILFS_I_UPDATED, &ii->i_state);
1009	}
1010}
1011
1012static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
1013				       struct inode *inode,
1014				       struct list_head *listp,
1015				       int (*collect)(struct nilfs_sc_info *,
1016						      struct buffer_head *,
1017						      struct inode *))
1018{
1019	struct buffer_head *bh, *n;
1020	int err = 0;
1021
1022	if (collect) {
1023		list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
1024			list_del_init(&bh->b_assoc_buffers);
1025			err = collect(sci, bh, inode);
1026			brelse(bh);
1027			if (unlikely(err))
1028				goto dispose_buffers;
1029		}
1030		return 0;
1031	}
1032
1033 dispose_buffers:
1034	while (!list_empty(listp)) {
1035		bh = list_first_entry(listp, struct buffer_head,
1036				      b_assoc_buffers);
1037		list_del_init(&bh->b_assoc_buffers);
1038		brelse(bh);
1039	}
1040	return err;
1041}
1042
1043static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
1044{
1045	/* Remaining number of blocks within segment buffer */
1046	return sci->sc_segbuf_nblocks -
1047		(sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
1048}
1049
1050static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
1051				   struct inode *inode,
1052				   const struct nilfs_sc_operations *sc_ops)
1053{
1054	LIST_HEAD(data_buffers);
1055	LIST_HEAD(node_buffers);
1056	int err;
1057
1058	if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1059		size_t n, rest = nilfs_segctor_buffer_rest(sci);
1060
1061		n = nilfs_lookup_dirty_data_buffers(
1062			inode, &data_buffers, rest + 1, 0, LLONG_MAX);
1063		if (n > rest) {
1064			err = nilfs_segctor_apply_buffers(
1065				sci, inode, &data_buffers,
1066				sc_ops->collect_data);
1067			BUG_ON(!err); /* always receive -E2BIG or true error */
1068			goto break_or_fail;
1069		}
1070	}
1071	nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
1072
1073	if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1074		err = nilfs_segctor_apply_buffers(
1075			sci, inode, &data_buffers, sc_ops->collect_data);
1076		if (unlikely(err)) {
1077			/* dispose node list */
1078			nilfs_segctor_apply_buffers(
1079				sci, inode, &node_buffers, NULL);
1080			goto break_or_fail;
1081		}
1082		sci->sc_stage.flags |= NILFS_CF_NODE;
1083	}
1084	/* Collect node */
1085	err = nilfs_segctor_apply_buffers(
1086		sci, inode, &node_buffers, sc_ops->collect_node);
1087	if (unlikely(err))
1088		goto break_or_fail;
1089
1090	nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1091	err = nilfs_segctor_apply_buffers(
1092		sci, inode, &node_buffers, sc_ops->collect_bmap);
1093	if (unlikely(err))
1094		goto break_or_fail;
1095
1096	nilfs_segctor_end_finfo(sci, inode);
1097	sci->sc_stage.flags &= ~NILFS_CF_NODE;
1098
1099 break_or_fail:
1100	return err;
1101}
1102
1103static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1104					 struct inode *inode)
1105{
1106	LIST_HEAD(data_buffers);
1107	size_t n, rest = nilfs_segctor_buffer_rest(sci);
1108	int err;
1109
1110	n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1111					    sci->sc_dsync_start,
1112					    sci->sc_dsync_end);
1113
1114	err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1115					  nilfs_collect_file_data);
1116	if (!err) {
1117		nilfs_segctor_end_finfo(sci, inode);
1118		BUG_ON(n > rest);
1119		/* always receive -E2BIG or true error if n > rest */
1120	}
1121	return err;
1122}
1123
1124static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1125{
1126	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1127	struct list_head *head;
1128	struct nilfs_inode_info *ii;
1129	size_t ndone;
1130	int err = 0;
1131
1132	switch (nilfs_sc_cstage_get(sci)) {
1133	case NILFS_ST_INIT:
1134		/* Pre-processes */
1135		sci->sc_stage.flags = 0;
1136
1137		if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1138			sci->sc_nblk_inc = 0;
1139			sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1140			if (mode == SC_LSEG_DSYNC) {
1141				nilfs_sc_cstage_set(sci, NILFS_ST_DSYNC);
1142				goto dsync_mode;
1143			}
1144		}
1145
1146		sci->sc_stage.dirty_file_ptr = NULL;
1147		sci->sc_stage.gc_inode_ptr = NULL;
1148		if (mode == SC_FLUSH_DAT) {
1149			nilfs_sc_cstage_set(sci, NILFS_ST_DAT);
1150			goto dat_stage;
1151		}
1152		nilfs_sc_cstage_inc(sci);  /* Fall through */
1153	case NILFS_ST_GC:
1154		if (nilfs_doing_gc()) {
1155			head = &sci->sc_gc_inodes;
1156			ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1157						head, i_dirty);
1158			list_for_each_entry_continue(ii, head, i_dirty) {
1159				err = nilfs_segctor_scan_file(
1160					sci, &ii->vfs_inode,
1161					&nilfs_sc_file_ops);
1162				if (unlikely(err)) {
1163					sci->sc_stage.gc_inode_ptr = list_entry(
1164						ii->i_dirty.prev,
1165						struct nilfs_inode_info,
1166						i_dirty);
1167					goto break_or_fail;
1168				}
1169				set_bit(NILFS_I_COLLECTED, &ii->i_state);
1170			}
1171			sci->sc_stage.gc_inode_ptr = NULL;
1172		}
1173		nilfs_sc_cstage_inc(sci);  /* Fall through */
1174	case NILFS_ST_FILE:
1175		head = &sci->sc_dirty_files;
1176		ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1177					i_dirty);
1178		list_for_each_entry_continue(ii, head, i_dirty) {
1179			clear_bit(NILFS_I_DIRTY, &ii->i_state);
1180
1181			err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1182						      &nilfs_sc_file_ops);
1183			if (unlikely(err)) {
1184				sci->sc_stage.dirty_file_ptr =
1185					list_entry(ii->i_dirty.prev,
1186						   struct nilfs_inode_info,
1187						   i_dirty);
1188				goto break_or_fail;
1189			}
1190			/* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1191			/* XXX: required ? */
1192		}
1193		sci->sc_stage.dirty_file_ptr = NULL;
1194		if (mode == SC_FLUSH_FILE) {
1195			nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1196			return 0;
1197		}
1198		nilfs_sc_cstage_inc(sci);
1199		sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1200		/* Fall through */
1201	case NILFS_ST_IFILE:
1202		err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1203					      &nilfs_sc_file_ops);
1204		if (unlikely(err))
1205			break;
1206		nilfs_sc_cstage_inc(sci);
1207		/* Creating a checkpoint */
1208		err = nilfs_segctor_create_checkpoint(sci);
1209		if (unlikely(err))
1210			break;
1211		/* Fall through */
1212	case NILFS_ST_CPFILE:
1213		err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1214					      &nilfs_sc_file_ops);
1215		if (unlikely(err))
1216			break;
1217		nilfs_sc_cstage_inc(sci);  /* Fall through */
1218	case NILFS_ST_SUFILE:
1219		err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1220					 sci->sc_nfreesegs, &ndone);
1221		if (unlikely(err)) {
1222			nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1223						  sci->sc_freesegs, ndone,
1224						  NULL);
1225			break;
1226		}
1227		sci->sc_stage.flags |= NILFS_CF_SUFREED;
1228
1229		err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1230					      &nilfs_sc_file_ops);
1231		if (unlikely(err))
1232			break;
1233		nilfs_sc_cstage_inc(sci);  /* Fall through */
1234	case NILFS_ST_DAT:
1235 dat_stage:
1236		err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1237					      &nilfs_sc_dat_ops);
1238		if (unlikely(err))
1239			break;
1240		if (mode == SC_FLUSH_DAT) {
1241			nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1242			return 0;
1243		}
1244		nilfs_sc_cstage_inc(sci);  /* Fall through */
1245	case NILFS_ST_SR:
1246		if (mode == SC_LSEG_SR) {
1247			/* Appending a super root */
1248			err = nilfs_segctor_add_super_root(sci);
1249			if (unlikely(err))
1250				break;
1251		}
1252		/* End of a logical segment */
1253		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1254		nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1255		return 0;
1256	case NILFS_ST_DSYNC:
1257 dsync_mode:
1258		sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1259		ii = sci->sc_dsync_inode;
1260		if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1261			break;
1262
1263		err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1264		if (unlikely(err))
1265			break;
1266		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1267		nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1268		return 0;
1269	case NILFS_ST_DONE:
1270		return 0;
1271	default:
1272		BUG();
1273	}
1274
1275 break_or_fail:
1276	return err;
1277}
1278
1279/**
1280 * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1281 * @sci: nilfs_sc_info
1282 * @nilfs: nilfs object
1283 */
1284static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1285					    struct the_nilfs *nilfs)
1286{
1287	struct nilfs_segment_buffer *segbuf, *prev;
1288	__u64 nextnum;
1289	int err, alloc = 0;
1290
1291	segbuf = nilfs_segbuf_new(sci->sc_super);
1292	if (unlikely(!segbuf))
1293		return -ENOMEM;
1294
1295	if (list_empty(&sci->sc_write_logs)) {
1296		nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1297				 nilfs->ns_pseg_offset, nilfs);
1298		if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1299			nilfs_shift_to_next_segment(nilfs);
1300			nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1301		}
1302
1303		segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1304		nextnum = nilfs->ns_nextnum;
1305
1306		if (nilfs->ns_segnum == nilfs->ns_nextnum)
1307			/* Start from the head of a new full segment */
1308			alloc++;
1309	} else {
1310		/* Continue logs */
1311		prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1312		nilfs_segbuf_map_cont(segbuf, prev);
1313		segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1314		nextnum = prev->sb_nextnum;
1315
1316		if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1317			nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1318			segbuf->sb_sum.seg_seq++;
1319			alloc++;
1320		}
1321	}
1322
1323	err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1324	if (err)
1325		goto failed;
1326
1327	if (alloc) {
1328		err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1329		if (err)
1330			goto failed;
1331	}
1332	nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1333
1334	BUG_ON(!list_empty(&sci->sc_segbufs));
1335	list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1336	sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1337	return 0;
1338
1339 failed:
1340	nilfs_segbuf_free(segbuf);
1341	return err;
1342}
1343
1344static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1345					 struct the_nilfs *nilfs, int nadd)
1346{
1347	struct nilfs_segment_buffer *segbuf, *prev;
1348	struct inode *sufile = nilfs->ns_sufile;
1349	__u64 nextnextnum;
1350	LIST_HEAD(list);
1351	int err, ret, i;
1352
1353	prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1354	/*
1355	 * Since the segment specified with nextnum might be allocated during
1356	 * the previous construction, the buffer including its segusage may
1357	 * not be dirty.  The following call ensures that the buffer is dirty
1358	 * and will pin the buffer on memory until the sufile is written.
1359	 */
1360	err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1361	if (unlikely(err))
1362		return err;
1363
1364	for (i = 0; i < nadd; i++) {
1365		/* extend segment info */
1366		err = -ENOMEM;
1367		segbuf = nilfs_segbuf_new(sci->sc_super);
1368		if (unlikely(!segbuf))
1369			goto failed;
1370
1371		/* map this buffer to region of segment on-disk */
1372		nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1373		sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1374
1375		/* allocate the next next full segment */
1376		err = nilfs_sufile_alloc(sufile, &nextnextnum);
1377		if (unlikely(err))
1378			goto failed_segbuf;
1379
1380		segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1381		nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1382
1383		list_add_tail(&segbuf->sb_list, &list);
1384		prev = segbuf;
1385	}
1386	list_splice_tail(&list, &sci->sc_segbufs);
1387	return 0;
1388
1389 failed_segbuf:
1390	nilfs_segbuf_free(segbuf);
1391 failed:
1392	list_for_each_entry(segbuf, &list, sb_list) {
1393		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1394		WARN_ON(ret); /* never fails */
1395	}
1396	nilfs_destroy_logs(&list);
1397	return err;
1398}
1399
1400static void nilfs_free_incomplete_logs(struct list_head *logs,
1401				       struct the_nilfs *nilfs)
1402{
1403	struct nilfs_segment_buffer *segbuf, *prev;
1404	struct inode *sufile = nilfs->ns_sufile;
1405	int ret;
1406
1407	segbuf = NILFS_FIRST_SEGBUF(logs);
1408	if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1409		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1410		WARN_ON(ret); /* never fails */
1411	}
1412	if (atomic_read(&segbuf->sb_err)) {
1413		/* Case 1: The first segment failed */
1414		if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1415			/*
1416			 * Case 1a:  Partial segment appended into an existing
1417			 * segment
1418			 */
1419			nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1420						segbuf->sb_fseg_end);
1421		else /* Case 1b:  New full segment */
1422			set_nilfs_discontinued(nilfs);
1423	}
1424
1425	prev = segbuf;
1426	list_for_each_entry_continue(segbuf, logs, sb_list) {
1427		if (prev->sb_nextnum != segbuf->sb_nextnum) {
1428			ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1429			WARN_ON(ret); /* never fails */
1430		}
1431		if (atomic_read(&segbuf->sb_err) &&
1432		    segbuf->sb_segnum != nilfs->ns_nextnum)
1433			/* Case 2: extended segment (!= next) failed */
1434			nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1435		prev = segbuf;
1436	}
1437}
1438
1439static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1440					  struct inode *sufile)
1441{
1442	struct nilfs_segment_buffer *segbuf;
1443	unsigned long live_blocks;
1444	int ret;
1445
1446	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1447		live_blocks = segbuf->sb_sum.nblocks +
1448			(segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1449		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1450						     live_blocks,
1451						     sci->sc_seg_ctime);
1452		WARN_ON(ret); /* always succeed because the segusage is dirty */
1453	}
1454}
1455
1456static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1457{
1458	struct nilfs_segment_buffer *segbuf;
1459	int ret;
1460
1461	segbuf = NILFS_FIRST_SEGBUF(logs);
1462	ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1463					     segbuf->sb_pseg_start -
1464					     segbuf->sb_fseg_start, 0);
1465	WARN_ON(ret); /* always succeed because the segusage is dirty */
1466
1467	list_for_each_entry_continue(segbuf, logs, sb_list) {
1468		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1469						     0, 0);
1470		WARN_ON(ret); /* always succeed */
1471	}
1472}
1473
1474static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1475					    struct nilfs_segment_buffer *last,
1476					    struct inode *sufile)
1477{
1478	struct nilfs_segment_buffer *segbuf = last;
1479	int ret;
1480
1481	list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1482		sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1483		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1484		WARN_ON(ret);
1485	}
1486	nilfs_truncate_logs(&sci->sc_segbufs, last);
1487}
1488
1489
1490static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1491				 struct the_nilfs *nilfs, int mode)
1492{
1493	struct nilfs_cstage prev_stage = sci->sc_stage;
1494	int err, nadd = 1;
1495
1496	/* Collection retry loop */
1497	for (;;) {
1498		sci->sc_nblk_this_inc = 0;
1499		sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1500
1501		err = nilfs_segctor_reset_segment_buffer(sci);
1502		if (unlikely(err))
1503			goto failed;
1504
1505		err = nilfs_segctor_collect_blocks(sci, mode);
1506		sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1507		if (!err)
1508			break;
1509
1510		if (unlikely(err != -E2BIG))
1511			goto failed;
1512
1513		/* The current segment is filled up */
1514		if (mode != SC_LSEG_SR ||
1515		    nilfs_sc_cstage_get(sci) < NILFS_ST_CPFILE)
1516			break;
1517
1518		nilfs_clear_logs(&sci->sc_segbufs);
1519
 
 
 
 
1520		if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1521			err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1522							sci->sc_freesegs,
1523							sci->sc_nfreesegs,
1524							NULL);
1525			WARN_ON(err); /* do not happen */
1526			sci->sc_stage.flags &= ~NILFS_CF_SUFREED;
1527		}
1528
1529		err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1530		if (unlikely(err))
1531			return err;
1532
1533		nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1534		sci->sc_stage = prev_stage;
1535	}
1536	nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1537	return 0;
1538
1539 failed:
1540	return err;
1541}
1542
1543static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1544				      struct buffer_head *new_bh)
1545{
1546	BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1547
1548	list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1549	/* The caller must release old_bh */
1550}
1551
1552static int
1553nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1554				     struct nilfs_segment_buffer *segbuf,
1555				     int mode)
1556{
1557	struct inode *inode = NULL;
1558	sector_t blocknr;
1559	unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1560	unsigned long nblocks = 0, ndatablk = 0;
1561	const struct nilfs_sc_operations *sc_op = NULL;
1562	struct nilfs_segsum_pointer ssp;
1563	struct nilfs_finfo *finfo = NULL;
1564	union nilfs_binfo binfo;
1565	struct buffer_head *bh, *bh_org;
1566	ino_t ino = 0;
1567	int err = 0;
1568
1569	if (!nfinfo)
1570		goto out;
1571
1572	blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1573	ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1574	ssp.offset = sizeof(struct nilfs_segment_summary);
1575
1576	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1577		if (bh == segbuf->sb_super_root)
1578			break;
1579		if (!finfo) {
1580			finfo =	nilfs_segctor_map_segsum_entry(
1581				sci, &ssp, sizeof(*finfo));
1582			ino = le64_to_cpu(finfo->fi_ino);
1583			nblocks = le32_to_cpu(finfo->fi_nblocks);
1584			ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1585
1586			inode = bh->b_page->mapping->host;
1587
1588			if (mode == SC_LSEG_DSYNC)
1589				sc_op = &nilfs_sc_dsync_ops;
1590			else if (ino == NILFS_DAT_INO)
1591				sc_op = &nilfs_sc_dat_ops;
1592			else /* file blocks */
1593				sc_op = &nilfs_sc_file_ops;
1594		}
1595		bh_org = bh;
1596		get_bh(bh_org);
1597		err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1598					&binfo);
1599		if (bh != bh_org)
1600			nilfs_list_replace_buffer(bh_org, bh);
1601		brelse(bh_org);
1602		if (unlikely(err))
1603			goto failed_bmap;
1604
1605		if (ndatablk > 0)
1606			sc_op->write_data_binfo(sci, &ssp, &binfo);
1607		else
1608			sc_op->write_node_binfo(sci, &ssp, &binfo);
1609
1610		blocknr++;
1611		if (--nblocks == 0) {
1612			finfo = NULL;
1613			if (--nfinfo == 0)
1614				break;
1615		} else if (ndatablk > 0)
1616			ndatablk--;
1617	}
1618 out:
1619	return 0;
1620
1621 failed_bmap:
1622	return err;
1623}
1624
1625static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1626{
1627	struct nilfs_segment_buffer *segbuf;
1628	int err;
1629
1630	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1631		err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1632		if (unlikely(err))
1633			return err;
1634		nilfs_segbuf_fill_in_segsum(segbuf);
1635	}
1636	return 0;
1637}
1638
1639static void nilfs_begin_page_io(struct page *page)
1640{
1641	if (!page || PageWriteback(page))
1642		/*
1643		 * For split b-tree node pages, this function may be called
1644		 * twice.  We ignore the 2nd or later calls by this check.
1645		 */
1646		return;
1647
1648	lock_page(page);
1649	clear_page_dirty_for_io(page);
1650	set_page_writeback(page);
1651	unlock_page(page);
1652}
1653
1654static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci)
1655{
1656	struct nilfs_segment_buffer *segbuf;
1657	struct page *bd_page = NULL, *fs_page = NULL;
1658
1659	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1660		struct buffer_head *bh;
1661
1662		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1663				    b_assoc_buffers) {
1664			if (bh->b_page != bd_page) {
1665				if (bd_page) {
1666					lock_page(bd_page);
1667					clear_page_dirty_for_io(bd_page);
1668					set_page_writeback(bd_page);
1669					unlock_page(bd_page);
1670				}
1671				bd_page = bh->b_page;
1672			}
1673		}
1674
1675		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1676				    b_assoc_buffers) {
1677			set_buffer_async_write(bh);
1678			if (bh == segbuf->sb_super_root) {
1679				if (bh->b_page != bd_page) {
1680					lock_page(bd_page);
1681					clear_page_dirty_for_io(bd_page);
1682					set_page_writeback(bd_page);
1683					unlock_page(bd_page);
1684					bd_page = bh->b_page;
1685				}
1686				break;
1687			}
1688			if (bh->b_page != fs_page) {
1689				nilfs_begin_page_io(fs_page);
1690				fs_page = bh->b_page;
1691			}
1692		}
1693	}
1694	if (bd_page) {
1695		lock_page(bd_page);
1696		clear_page_dirty_for_io(bd_page);
1697		set_page_writeback(bd_page);
1698		unlock_page(bd_page);
1699	}
1700	nilfs_begin_page_io(fs_page);
1701}
1702
1703static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1704			       struct the_nilfs *nilfs)
1705{
1706	int ret;
1707
1708	ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1709	list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1710	return ret;
1711}
1712
1713static void nilfs_end_page_io(struct page *page, int err)
1714{
1715	if (!page)
1716		return;
1717
1718	if (buffer_nilfs_node(page_buffers(page)) && !PageWriteback(page)) {
1719		/*
1720		 * For b-tree node pages, this function may be called twice
1721		 * or more because they might be split in a segment.
1722		 */
1723		if (PageDirty(page)) {
1724			/*
1725			 * For pages holding split b-tree node buffers, dirty
1726			 * flag on the buffers may be cleared discretely.
1727			 * In that case, the page is once redirtied for
1728			 * remaining buffers, and it must be cancelled if
1729			 * all the buffers get cleaned later.
1730			 */
1731			lock_page(page);
1732			if (nilfs_page_buffers_clean(page))
1733				__nilfs_clear_page_dirty(page);
1734			unlock_page(page);
1735		}
1736		return;
1737	}
1738
1739	if (!err) {
1740		if (!nilfs_page_buffers_clean(page))
1741			__set_page_dirty_nobuffers(page);
1742		ClearPageError(page);
1743	} else {
1744		__set_page_dirty_nobuffers(page);
1745		SetPageError(page);
1746	}
1747
1748	end_page_writeback(page);
1749}
1750
1751static void nilfs_abort_logs(struct list_head *logs, int err)
1752{
1753	struct nilfs_segment_buffer *segbuf;
1754	struct page *bd_page = NULL, *fs_page = NULL;
1755	struct buffer_head *bh;
1756
1757	if (list_empty(logs))
1758		return;
1759
1760	list_for_each_entry(segbuf, logs, sb_list) {
1761		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1762				    b_assoc_buffers) {
1763			if (bh->b_page != bd_page) {
1764				if (bd_page)
1765					end_page_writeback(bd_page);
1766				bd_page = bh->b_page;
1767			}
1768		}
1769
1770		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1771				    b_assoc_buffers) {
1772			clear_buffer_async_write(bh);
1773			if (bh == segbuf->sb_super_root) {
1774				if (bh->b_page != bd_page) {
1775					end_page_writeback(bd_page);
1776					bd_page = bh->b_page;
1777				}
1778				break;
1779			}
1780			if (bh->b_page != fs_page) {
1781				nilfs_end_page_io(fs_page, err);
1782				fs_page = bh->b_page;
1783			}
1784		}
1785	}
1786	if (bd_page)
1787		end_page_writeback(bd_page);
1788
1789	nilfs_end_page_io(fs_page, err);
1790}
1791
1792static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
1793					     struct the_nilfs *nilfs, int err)
1794{
1795	LIST_HEAD(logs);
1796	int ret;
1797
1798	list_splice_tail_init(&sci->sc_write_logs, &logs);
1799	ret = nilfs_wait_on_logs(&logs);
1800	nilfs_abort_logs(&logs, ret ? : err);
1801
1802	list_splice_tail_init(&sci->sc_segbufs, &logs);
1803	nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
1804	nilfs_free_incomplete_logs(&logs, nilfs);
1805
1806	if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1807		ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1808						sci->sc_freesegs,
1809						sci->sc_nfreesegs,
1810						NULL);
1811		WARN_ON(ret); /* do not happen */
1812	}
1813
1814	nilfs_destroy_logs(&logs);
1815}
1816
1817static void nilfs_set_next_segment(struct the_nilfs *nilfs,
1818				   struct nilfs_segment_buffer *segbuf)
1819{
1820	nilfs->ns_segnum = segbuf->sb_segnum;
1821	nilfs->ns_nextnum = segbuf->sb_nextnum;
1822	nilfs->ns_pseg_offset = segbuf->sb_pseg_start - segbuf->sb_fseg_start
1823		+ segbuf->sb_sum.nblocks;
1824	nilfs->ns_seg_seq = segbuf->sb_sum.seg_seq;
1825	nilfs->ns_ctime = segbuf->sb_sum.ctime;
1826}
1827
1828static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
1829{
1830	struct nilfs_segment_buffer *segbuf;
1831	struct page *bd_page = NULL, *fs_page = NULL;
1832	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1833	int update_sr = false;
1834
1835	list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
1836		struct buffer_head *bh;
1837
1838		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1839				    b_assoc_buffers) {
1840			set_buffer_uptodate(bh);
1841			clear_buffer_dirty(bh);
1842			if (bh->b_page != bd_page) {
1843				if (bd_page)
1844					end_page_writeback(bd_page);
1845				bd_page = bh->b_page;
1846			}
1847		}
1848		/*
1849		 * We assume that the buffers which belong to the same page
1850		 * continue over the buffer list.
1851		 * Under this assumption, the last BHs of pages is
1852		 * identifiable by the discontinuity of bh->b_page
1853		 * (page != fs_page).
1854		 *
1855		 * For B-tree node blocks, however, this assumption is not
1856		 * guaranteed.  The cleanup code of B-tree node pages needs
1857		 * special care.
1858		 */
1859		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1860				    b_assoc_buffers) {
1861			const unsigned long set_bits = BIT(BH_Uptodate);
1862			const unsigned long clear_bits =
1863				(BIT(BH_Dirty) | BIT(BH_Async_Write) |
1864				 BIT(BH_Delay) | BIT(BH_NILFS_Volatile) |
1865				 BIT(BH_NILFS_Redirected));
1866
1867			set_mask_bits(&bh->b_state, clear_bits, set_bits);
1868			if (bh == segbuf->sb_super_root) {
1869				if (bh->b_page != bd_page) {
1870					end_page_writeback(bd_page);
1871					bd_page = bh->b_page;
1872				}
1873				update_sr = true;
1874				break;
1875			}
1876			if (bh->b_page != fs_page) {
1877				nilfs_end_page_io(fs_page, 0);
1878				fs_page = bh->b_page;
1879			}
1880		}
1881
1882		if (!nilfs_segbuf_simplex(segbuf)) {
1883			if (segbuf->sb_sum.flags & NILFS_SS_LOGBGN) {
1884				set_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1885				sci->sc_lseg_stime = jiffies;
1886			}
1887			if (segbuf->sb_sum.flags & NILFS_SS_LOGEND)
1888				clear_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1889		}
1890	}
1891	/*
1892	 * Since pages may continue over multiple segment buffers,
1893	 * end of the last page must be checked outside of the loop.
1894	 */
1895	if (bd_page)
1896		end_page_writeback(bd_page);
1897
1898	nilfs_end_page_io(fs_page, 0);
1899
1900	nilfs_drop_collected_inodes(&sci->sc_dirty_files);
1901
1902	if (nilfs_doing_gc())
1903		nilfs_drop_collected_inodes(&sci->sc_gc_inodes);
1904	else
1905		nilfs->ns_nongc_ctime = sci->sc_seg_ctime;
1906
1907	sci->sc_nblk_inc += sci->sc_nblk_this_inc;
1908
1909	segbuf = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1910	nilfs_set_next_segment(nilfs, segbuf);
1911
1912	if (update_sr) {
1913		nilfs->ns_flushed_device = 0;
1914		nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
1915				       segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
1916
1917		clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
1918		clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1919		set_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1920		nilfs_segctor_clear_metadata_dirty(sci);
1921	} else
1922		clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1923}
1924
1925static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
1926{
1927	int ret;
1928
1929	ret = nilfs_wait_on_logs(&sci->sc_write_logs);
1930	if (!ret) {
1931		nilfs_segctor_complete_write(sci);
1932		nilfs_destroy_logs(&sci->sc_write_logs);
1933	}
1934	return ret;
1935}
1936
1937static int nilfs_segctor_collect_dirty_files(struct nilfs_sc_info *sci,
1938					     struct the_nilfs *nilfs)
1939{
1940	struct nilfs_inode_info *ii, *n;
1941	struct inode *ifile = sci->sc_root->ifile;
1942
1943	spin_lock(&nilfs->ns_inode_lock);
1944 retry:
1945	list_for_each_entry_safe(ii, n, &nilfs->ns_dirty_files, i_dirty) {
1946		if (!ii->i_bh) {
1947			struct buffer_head *ibh;
1948			int err;
1949
1950			spin_unlock(&nilfs->ns_inode_lock);
1951			err = nilfs_ifile_get_inode_block(
1952				ifile, ii->vfs_inode.i_ino, &ibh);
1953			if (unlikely(err)) {
1954				nilfs_msg(sci->sc_super, KERN_WARNING,
1955					  "log writer: error %d getting inode block (ino=%lu)",
1956					  err, ii->vfs_inode.i_ino);
1957				return err;
1958			}
1959			mark_buffer_dirty(ibh);
1960			nilfs_mdt_mark_dirty(ifile);
1961			spin_lock(&nilfs->ns_inode_lock);
1962			if (likely(!ii->i_bh))
1963				ii->i_bh = ibh;
1964			else
1965				brelse(ibh);
1966			goto retry;
1967		}
1968
1969		clear_bit(NILFS_I_QUEUED, &ii->i_state);
1970		set_bit(NILFS_I_BUSY, &ii->i_state);
1971		list_move_tail(&ii->i_dirty, &sci->sc_dirty_files);
1972	}
1973	spin_unlock(&nilfs->ns_inode_lock);
1974
1975	return 0;
1976}
1977
1978static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
1979					     struct the_nilfs *nilfs)
1980{
 
1981	struct nilfs_inode_info *ii, *n;
1982	int during_mount = !(sci->sc_super->s_flags & MS_ACTIVE);
1983	int defer_iput = false;
1984
1985	spin_lock(&nilfs->ns_inode_lock);
1986	list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
1987		if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
1988		    test_bit(NILFS_I_DIRTY, &ii->i_state))
1989			continue;
1990
1991		clear_bit(NILFS_I_BUSY, &ii->i_state);
1992		brelse(ii->i_bh);
1993		ii->i_bh = NULL;
1994		list_del_init(&ii->i_dirty);
1995		if (!ii->vfs_inode.i_nlink || during_mount) {
1996			/*
1997			 * Defer calling iput() to avoid deadlocks if
1998			 * i_nlink == 0 or mount is not yet finished.
1999			 */
2000			list_add_tail(&ii->i_dirty, &sci->sc_iput_queue);
2001			defer_iput = true;
2002		} else {
2003			spin_unlock(&nilfs->ns_inode_lock);
2004			iput(&ii->vfs_inode);
2005			spin_lock(&nilfs->ns_inode_lock);
2006		}
2007	}
2008	spin_unlock(&nilfs->ns_inode_lock);
2009
2010	if (defer_iput)
2011		schedule_work(&sci->sc_iput_work);
2012}
2013
2014/*
2015 * Main procedure of segment constructor
2016 */
2017static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
2018{
2019	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2020	int err;
2021
2022	nilfs_sc_cstage_set(sci, NILFS_ST_INIT);
2023	sci->sc_cno = nilfs->ns_cno;
2024
2025	err = nilfs_segctor_collect_dirty_files(sci, nilfs);
2026	if (unlikely(err))
2027		goto out;
2028
2029	if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
2030		set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
2031
2032	if (nilfs_segctor_clean(sci))
2033		goto out;
2034
2035	do {
2036		sci->sc_stage.flags &= ~NILFS_CF_HISTORY_MASK;
2037
2038		err = nilfs_segctor_begin_construction(sci, nilfs);
2039		if (unlikely(err))
2040			goto out;
2041
2042		/* Update time stamp */
2043		sci->sc_seg_ctime = get_seconds();
2044
2045		err = nilfs_segctor_collect(sci, nilfs, mode);
2046		if (unlikely(err))
2047			goto failed;
2048
2049		/* Avoid empty segment */
2050		if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE &&
2051		    nilfs_segbuf_empty(sci->sc_curseg)) {
2052			nilfs_segctor_abort_construction(sci, nilfs, 1);
2053			goto out;
2054		}
2055
2056		err = nilfs_segctor_assign(sci, mode);
2057		if (unlikely(err))
2058			goto failed;
2059
2060		if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2061			nilfs_segctor_fill_in_file_bmap(sci);
2062
2063		if (mode == SC_LSEG_SR &&
2064		    nilfs_sc_cstage_get(sci) >= NILFS_ST_CPFILE) {
2065			err = nilfs_segctor_fill_in_checkpoint(sci);
2066			if (unlikely(err))
2067				goto failed_to_write;
2068
2069			nilfs_segctor_fill_in_super_root(sci, nilfs);
2070		}
2071		nilfs_segctor_update_segusage(sci, nilfs->ns_sufile);
2072
2073		/* Write partial segments */
2074		nilfs_segctor_prepare_write(sci);
2075
2076		nilfs_add_checksums_on_logs(&sci->sc_segbufs,
2077					    nilfs->ns_crc_seed);
2078
2079		err = nilfs_segctor_write(sci, nilfs);
2080		if (unlikely(err))
2081			goto failed_to_write;
2082
2083		if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE ||
2084		    nilfs->ns_blocksize_bits != PAGE_SHIFT) {
2085			/*
2086			 * At this point, we avoid double buffering
2087			 * for blocksize < pagesize because page dirty
2088			 * flag is turned off during write and dirty
2089			 * buffers are not properly collected for
2090			 * pages crossing over segments.
2091			 */
2092			err = nilfs_segctor_wait(sci);
2093			if (err)
2094				goto failed_to_write;
2095		}
2096	} while (nilfs_sc_cstage_get(sci) != NILFS_ST_DONE);
2097
2098 out:
2099	nilfs_segctor_drop_written_files(sci, nilfs);
2100	return err;
2101
2102 failed_to_write:
2103	if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2104		nilfs_redirty_inodes(&sci->sc_dirty_files);
2105
2106 failed:
2107	if (nilfs_doing_gc())
2108		nilfs_redirty_inodes(&sci->sc_gc_inodes);
2109	nilfs_segctor_abort_construction(sci, nilfs, err);
2110	goto out;
2111}
2112
2113/**
2114 * nilfs_segctor_start_timer - set timer of background write
2115 * @sci: nilfs_sc_info
2116 *
2117 * If the timer has already been set, it ignores the new request.
2118 * This function MUST be called within a section locking the segment
2119 * semaphore.
2120 */
2121static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
2122{
2123	spin_lock(&sci->sc_state_lock);
2124	if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
2125		sci->sc_timer.expires = jiffies + sci->sc_interval;
2126		add_timer(&sci->sc_timer);
2127		sci->sc_state |= NILFS_SEGCTOR_COMMIT;
2128	}
2129	spin_unlock(&sci->sc_state_lock);
2130}
2131
2132static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
2133{
2134	spin_lock(&sci->sc_state_lock);
2135	if (!(sci->sc_flush_request & BIT(bn))) {
2136		unsigned long prev_req = sci->sc_flush_request;
2137
2138		sci->sc_flush_request |= BIT(bn);
2139		if (!prev_req)
2140			wake_up(&sci->sc_wait_daemon);
2141	}
2142	spin_unlock(&sci->sc_state_lock);
2143}
2144
2145/**
2146 * nilfs_flush_segment - trigger a segment construction for resource control
2147 * @sb: super block
2148 * @ino: inode number of the file to be flushed out.
2149 */
2150void nilfs_flush_segment(struct super_block *sb, ino_t ino)
2151{
2152	struct the_nilfs *nilfs = sb->s_fs_info;
2153	struct nilfs_sc_info *sci = nilfs->ns_writer;
2154
2155	if (!sci || nilfs_doing_construction())
2156		return;
2157	nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
2158					/* assign bit 0 to data files */
2159}
2160
2161struct nilfs_segctor_wait_request {
2162	wait_queue_t	wq;
2163	__u32		seq;
2164	int		err;
2165	atomic_t	done;
2166};
2167
2168static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
2169{
2170	struct nilfs_segctor_wait_request wait_req;
2171	int err = 0;
2172
2173	spin_lock(&sci->sc_state_lock);
2174	init_wait(&wait_req.wq);
2175	wait_req.err = 0;
2176	atomic_set(&wait_req.done, 0);
2177	wait_req.seq = ++sci->sc_seq_request;
2178	spin_unlock(&sci->sc_state_lock);
2179
2180	init_waitqueue_entry(&wait_req.wq, current);
2181	add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
2182	set_current_state(TASK_INTERRUPTIBLE);
2183	wake_up(&sci->sc_wait_daemon);
2184
2185	for (;;) {
2186		if (atomic_read(&wait_req.done)) {
2187			err = wait_req.err;
2188			break;
2189		}
2190		if (!signal_pending(current)) {
2191			schedule();
2192			continue;
2193		}
2194		err = -ERESTARTSYS;
2195		break;
2196	}
2197	finish_wait(&sci->sc_wait_request, &wait_req.wq);
2198	return err;
2199}
2200
2201static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
2202{
2203	struct nilfs_segctor_wait_request *wrq, *n;
2204	unsigned long flags;
2205
2206	spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
2207	list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.task_list,
2208				 wq.task_list) {
2209		if (!atomic_read(&wrq->done) &&
2210		    nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
2211			wrq->err = err;
2212			atomic_set(&wrq->done, 1);
2213		}
2214		if (atomic_read(&wrq->done)) {
2215			wrq->wq.func(&wrq->wq,
2216				     TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
2217				     0, NULL);
2218		}
2219	}
2220	spin_unlock_irqrestore(&sci->sc_wait_request.lock, flags);
2221}
2222
2223/**
2224 * nilfs_construct_segment - construct a logical segment
2225 * @sb: super block
2226 *
2227 * Return Value: On success, 0 is retured. On errors, one of the following
2228 * negative error code is returned.
2229 *
2230 * %-EROFS - Read only filesystem.
2231 *
2232 * %-EIO - I/O error
2233 *
2234 * %-ENOSPC - No space left on device (only in a panic state).
2235 *
2236 * %-ERESTARTSYS - Interrupted.
2237 *
2238 * %-ENOMEM - Insufficient memory available.
2239 */
2240int nilfs_construct_segment(struct super_block *sb)
2241{
2242	struct the_nilfs *nilfs = sb->s_fs_info;
2243	struct nilfs_sc_info *sci = nilfs->ns_writer;
2244	struct nilfs_transaction_info *ti;
2245	int err;
2246
2247	if (!sci)
2248		return -EROFS;
2249
2250	/* A call inside transactions causes a deadlock. */
2251	BUG_ON((ti = current->journal_info) && ti->ti_magic == NILFS_TI_MAGIC);
2252
2253	err = nilfs_segctor_sync(sci);
2254	return err;
2255}
2256
2257/**
2258 * nilfs_construct_dsync_segment - construct a data-only logical segment
2259 * @sb: super block
2260 * @inode: inode whose data blocks should be written out
2261 * @start: start byte offset
2262 * @end: end byte offset (inclusive)
2263 *
2264 * Return Value: On success, 0 is retured. On errors, one of the following
2265 * negative error code is returned.
2266 *
2267 * %-EROFS - Read only filesystem.
2268 *
2269 * %-EIO - I/O error
2270 *
2271 * %-ENOSPC - No space left on device (only in a panic state).
2272 *
2273 * %-ERESTARTSYS - Interrupted.
2274 *
2275 * %-ENOMEM - Insufficient memory available.
2276 */
2277int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
2278				  loff_t start, loff_t end)
2279{
2280	struct the_nilfs *nilfs = sb->s_fs_info;
2281	struct nilfs_sc_info *sci = nilfs->ns_writer;
2282	struct nilfs_inode_info *ii;
2283	struct nilfs_transaction_info ti;
2284	int err = 0;
2285
2286	if (!sci)
2287		return -EROFS;
2288
2289	nilfs_transaction_lock(sb, &ti, 0);
2290
2291	ii = NILFS_I(inode);
2292	if (test_bit(NILFS_I_INODE_SYNC, &ii->i_state) ||
2293	    nilfs_test_opt(nilfs, STRICT_ORDER) ||
2294	    test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2295	    nilfs_discontinued(nilfs)) {
2296		nilfs_transaction_unlock(sb);
2297		err = nilfs_segctor_sync(sci);
2298		return err;
2299	}
2300
2301	spin_lock(&nilfs->ns_inode_lock);
2302	if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
2303	    !test_bit(NILFS_I_BUSY, &ii->i_state)) {
2304		spin_unlock(&nilfs->ns_inode_lock);
2305		nilfs_transaction_unlock(sb);
2306		return 0;
2307	}
2308	spin_unlock(&nilfs->ns_inode_lock);
2309	sci->sc_dsync_inode = ii;
2310	sci->sc_dsync_start = start;
2311	sci->sc_dsync_end = end;
2312
2313	err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC);
2314	if (!err)
2315		nilfs->ns_flushed_device = 0;
2316
2317	nilfs_transaction_unlock(sb);
2318	return err;
2319}
2320
2321#define FLUSH_FILE_BIT	(0x1) /* data file only */
2322#define FLUSH_DAT_BIT	BIT(NILFS_DAT_INO) /* DAT only */
2323
2324/**
2325 * nilfs_segctor_accept - record accepted sequence count of log-write requests
2326 * @sci: segment constructor object
2327 */
2328static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
2329{
2330	spin_lock(&sci->sc_state_lock);
2331	sci->sc_seq_accepted = sci->sc_seq_request;
2332	spin_unlock(&sci->sc_state_lock);
2333	del_timer_sync(&sci->sc_timer);
2334}
2335
2336/**
2337 * nilfs_segctor_notify - notify the result of request to caller threads
2338 * @sci: segment constructor object
2339 * @mode: mode of log forming
2340 * @err: error code to be notified
2341 */
2342static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
2343{
2344	/* Clear requests (even when the construction failed) */
2345	spin_lock(&sci->sc_state_lock);
2346
2347	if (mode == SC_LSEG_SR) {
2348		sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
2349		sci->sc_seq_done = sci->sc_seq_accepted;
2350		nilfs_segctor_wakeup(sci, err);
2351		sci->sc_flush_request = 0;
2352	} else {
2353		if (mode == SC_FLUSH_FILE)
2354			sci->sc_flush_request &= ~FLUSH_FILE_BIT;
2355		else if (mode == SC_FLUSH_DAT)
2356			sci->sc_flush_request &= ~FLUSH_DAT_BIT;
2357
2358		/* re-enable timer if checkpoint creation was not done */
2359		if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2360		    time_before(jiffies, sci->sc_timer.expires))
2361			add_timer(&sci->sc_timer);
2362	}
2363	spin_unlock(&sci->sc_state_lock);
2364}
2365
2366/**
2367 * nilfs_segctor_construct - form logs and write them to disk
2368 * @sci: segment constructor object
2369 * @mode: mode of log forming
2370 */
2371static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
2372{
2373	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2374	struct nilfs_super_block **sbp;
2375	int err = 0;
2376
2377	nilfs_segctor_accept(sci);
2378
2379	if (nilfs_discontinued(nilfs))
2380		mode = SC_LSEG_SR;
2381	if (!nilfs_segctor_confirm(sci))
2382		err = nilfs_segctor_do_construct(sci, mode);
2383
2384	if (likely(!err)) {
2385		if (mode != SC_FLUSH_DAT)
2386			atomic_set(&nilfs->ns_ndirtyblks, 0);
2387		if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
2388		    nilfs_discontinued(nilfs)) {
2389			down_write(&nilfs->ns_sem);
2390			err = -EIO;
2391			sbp = nilfs_prepare_super(sci->sc_super,
2392						  nilfs_sb_will_flip(nilfs));
2393			if (likely(sbp)) {
2394				nilfs_set_log_cursor(sbp[0], nilfs);
2395				err = nilfs_commit_super(sci->sc_super,
2396							 NILFS_SB_COMMIT);
2397			}
2398			up_write(&nilfs->ns_sem);
2399		}
2400	}
2401
2402	nilfs_segctor_notify(sci, mode, err);
2403	return err;
2404}
2405
2406static void nilfs_construction_timeout(unsigned long data)
2407{
2408	struct task_struct *p = (struct task_struct *)data;
2409
2410	wake_up_process(p);
2411}
2412
2413static void
2414nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
2415{
2416	struct nilfs_inode_info *ii, *n;
2417
2418	list_for_each_entry_safe(ii, n, head, i_dirty) {
2419		if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
2420			continue;
2421		list_del_init(&ii->i_dirty);
2422		truncate_inode_pages(&ii->vfs_inode.i_data, 0);
2423		nilfs_btnode_cache_clear(&ii->i_btnode_cache);
2424		iput(&ii->vfs_inode);
2425	}
2426}
2427
2428int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
2429			 void **kbufs)
2430{
2431	struct the_nilfs *nilfs = sb->s_fs_info;
2432	struct nilfs_sc_info *sci = nilfs->ns_writer;
2433	struct nilfs_transaction_info ti;
2434	int err;
2435
2436	if (unlikely(!sci))
2437		return -EROFS;
2438
2439	nilfs_transaction_lock(sb, &ti, 1);
2440
2441	err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
2442	if (unlikely(err))
2443		goto out_unlock;
2444
2445	err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
2446	if (unlikely(err)) {
2447		nilfs_mdt_restore_from_shadow_map(nilfs->ns_dat);
2448		goto out_unlock;
2449	}
2450
2451	sci->sc_freesegs = kbufs[4];
2452	sci->sc_nfreesegs = argv[4].v_nmembs;
2453	list_splice_tail_init(&nilfs->ns_gc_inodes, &sci->sc_gc_inodes);
2454
2455	for (;;) {
2456		err = nilfs_segctor_construct(sci, SC_LSEG_SR);
2457		nilfs_remove_written_gcinodes(nilfs, &sci->sc_gc_inodes);
2458
2459		if (likely(!err))
2460			break;
2461
2462		nilfs_msg(sb, KERN_WARNING, "error %d cleaning segments", err);
 
2463		set_current_state(TASK_INTERRUPTIBLE);
2464		schedule_timeout(sci->sc_interval);
2465	}
2466	if (nilfs_test_opt(nilfs, DISCARD)) {
2467		int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
2468						 sci->sc_nfreesegs);
2469		if (ret) {
2470			nilfs_msg(sb, KERN_WARNING,
2471				  "error %d on discard request, turning discards off for the device",
2472				  ret);
2473			nilfs_clear_opt(nilfs, DISCARD);
2474		}
2475	}
2476
2477 out_unlock:
2478	sci->sc_freesegs = NULL;
2479	sci->sc_nfreesegs = 0;
2480	nilfs_mdt_clear_shadow_map(nilfs->ns_dat);
2481	nilfs_transaction_unlock(sb);
2482	return err;
2483}
2484
2485static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
2486{
2487	struct nilfs_transaction_info ti;
2488
2489	nilfs_transaction_lock(sci->sc_super, &ti, 0);
2490	nilfs_segctor_construct(sci, mode);
2491
2492	/*
2493	 * Unclosed segment should be retried.  We do this using sc_timer.
2494	 * Timeout of sc_timer will invoke complete construction which leads
2495	 * to close the current logical segment.
2496	 */
2497	if (test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags))
2498		nilfs_segctor_start_timer(sci);
2499
2500	nilfs_transaction_unlock(sci->sc_super);
2501}
2502
2503static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
2504{
2505	int mode = 0;
 
2506
2507	spin_lock(&sci->sc_state_lock);
2508	mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
2509		SC_FLUSH_DAT : SC_FLUSH_FILE;
2510	spin_unlock(&sci->sc_state_lock);
2511
2512	if (mode) {
2513		nilfs_segctor_do_construct(sci, mode);
2514
2515		spin_lock(&sci->sc_state_lock);
2516		sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
2517			~FLUSH_FILE_BIT : ~FLUSH_DAT_BIT;
2518		spin_unlock(&sci->sc_state_lock);
2519	}
2520	clear_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
2521}
2522
2523static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
2524{
2525	if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2526	    time_before(jiffies, sci->sc_lseg_stime + sci->sc_mjcp_freq)) {
2527		if (!(sci->sc_flush_request & ~FLUSH_FILE_BIT))
2528			return SC_FLUSH_FILE;
2529		else if (!(sci->sc_flush_request & ~FLUSH_DAT_BIT))
2530			return SC_FLUSH_DAT;
2531	}
2532	return SC_LSEG_SR;
2533}
2534
2535/**
2536 * nilfs_segctor_thread - main loop of the segment constructor thread.
2537 * @arg: pointer to a struct nilfs_sc_info.
2538 *
2539 * nilfs_segctor_thread() initializes a timer and serves as a daemon
2540 * to execute segment constructions.
2541 */
2542static int nilfs_segctor_thread(void *arg)
2543{
2544	struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
2545	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2546	int timeout = 0;
2547
2548	sci->sc_timer.data = (unsigned long)current;
2549	sci->sc_timer.function = nilfs_construction_timeout;
2550
2551	/* start sync. */
2552	sci->sc_task = current;
2553	wake_up(&sci->sc_wait_task); /* for nilfs_segctor_start_thread() */
2554	nilfs_msg(sci->sc_super, KERN_INFO,
2555		  "segctord starting. Construction interval = %lu seconds, CP frequency < %lu seconds",
2556		  sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
 
2557
2558	spin_lock(&sci->sc_state_lock);
2559 loop:
2560	for (;;) {
2561		int mode;
2562
2563		if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2564			goto end_thread;
2565
2566		if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2567			mode = SC_LSEG_SR;
2568		else if (sci->sc_flush_request)
2569			mode = nilfs_segctor_flush_mode(sci);
2570		else
2571			break;
 
 
2572
2573		spin_unlock(&sci->sc_state_lock);
2574		nilfs_segctor_thread_construct(sci, mode);
2575		spin_lock(&sci->sc_state_lock);
2576		timeout = 0;
2577	}
2578
2579
2580	if (freezing(current)) {
2581		spin_unlock(&sci->sc_state_lock);
2582		try_to_freeze();
2583		spin_lock(&sci->sc_state_lock);
2584	} else {
2585		DEFINE_WAIT(wait);
2586		int should_sleep = 1;
2587
2588		prepare_to_wait(&sci->sc_wait_daemon, &wait,
2589				TASK_INTERRUPTIBLE);
2590
2591		if (sci->sc_seq_request != sci->sc_seq_done)
2592			should_sleep = 0;
2593		else if (sci->sc_flush_request)
2594			should_sleep = 0;
2595		else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2596			should_sleep = time_before(jiffies,
2597					sci->sc_timer.expires);
2598
2599		if (should_sleep) {
2600			spin_unlock(&sci->sc_state_lock);
2601			schedule();
2602			spin_lock(&sci->sc_state_lock);
2603		}
2604		finish_wait(&sci->sc_wait_daemon, &wait);
2605		timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2606			   time_after_eq(jiffies, sci->sc_timer.expires));
2607
2608		if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2609			set_nilfs_discontinued(nilfs);
2610	}
2611	goto loop;
2612
2613 end_thread:
2614	spin_unlock(&sci->sc_state_lock);
2615
2616	/* end sync. */
2617	sci->sc_task = NULL;
2618	wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
2619	return 0;
2620}
2621
2622static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2623{
2624	struct task_struct *t;
2625
2626	t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2627	if (IS_ERR(t)) {
2628		int err = PTR_ERR(t);
2629
2630		nilfs_msg(sci->sc_super, KERN_ERR,
2631			  "error %d creating segctord thread", err);
2632		return err;
2633	}
2634	wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2635	return 0;
2636}
2637
2638static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2639	__acquires(&sci->sc_state_lock)
2640	__releases(&sci->sc_state_lock)
2641{
2642	sci->sc_state |= NILFS_SEGCTOR_QUIT;
2643
2644	while (sci->sc_task) {
2645		wake_up(&sci->sc_wait_daemon);
2646		spin_unlock(&sci->sc_state_lock);
2647		wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2648		spin_lock(&sci->sc_state_lock);
2649	}
2650}
2651
2652/*
2653 * Setup & clean-up functions
2654 */
2655static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
2656					       struct nilfs_root *root)
2657{
2658	struct the_nilfs *nilfs = sb->s_fs_info;
2659	struct nilfs_sc_info *sci;
2660
2661	sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2662	if (!sci)
2663		return NULL;
2664
2665	sci->sc_super = sb;
2666
2667	nilfs_get_root(root);
2668	sci->sc_root = root;
2669
2670	init_waitqueue_head(&sci->sc_wait_request);
2671	init_waitqueue_head(&sci->sc_wait_daemon);
2672	init_waitqueue_head(&sci->sc_wait_task);
2673	spin_lock_init(&sci->sc_state_lock);
2674	INIT_LIST_HEAD(&sci->sc_dirty_files);
2675	INIT_LIST_HEAD(&sci->sc_segbufs);
2676	INIT_LIST_HEAD(&sci->sc_write_logs);
2677	INIT_LIST_HEAD(&sci->sc_gc_inodes);
2678	INIT_LIST_HEAD(&sci->sc_iput_queue);
2679	INIT_WORK(&sci->sc_iput_work, nilfs_iput_work_func);
2680	init_timer(&sci->sc_timer);
2681
2682	sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2683	sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2684	sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2685
2686	if (nilfs->ns_interval)
2687		sci->sc_interval = HZ * nilfs->ns_interval;
2688	if (nilfs->ns_watermark)
2689		sci->sc_watermark = nilfs->ns_watermark;
2690	return sci;
2691}
2692
2693static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2694{
2695	int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2696
2697	/*
2698	 * The segctord thread was stopped and its timer was removed.
2699	 * But some tasks remain.
2700	 */
2701	do {
2702		struct nilfs_transaction_info ti;
2703
2704		nilfs_transaction_lock(sci->sc_super, &ti, 0);
2705		ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2706		nilfs_transaction_unlock(sci->sc_super);
2707
2708		flush_work(&sci->sc_iput_work);
2709
2710	} while (ret && retrycount-- > 0);
2711}
2712
2713/**
2714 * nilfs_segctor_destroy - destroy the segment constructor.
2715 * @sci: nilfs_sc_info
2716 *
2717 * nilfs_segctor_destroy() kills the segctord thread and frees
2718 * the nilfs_sc_info struct.
2719 * Caller must hold the segment semaphore.
2720 */
2721static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2722{
2723	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2724	int flag;
2725
2726	up_write(&nilfs->ns_segctor_sem);
2727
2728	spin_lock(&sci->sc_state_lock);
2729	nilfs_segctor_kill_thread(sci);
2730	flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2731		|| sci->sc_seq_request != sci->sc_seq_done);
2732	spin_unlock(&sci->sc_state_lock);
2733
2734	if (flush_work(&sci->sc_iput_work))
2735		flag = true;
2736
2737	if (flag || !nilfs_segctor_confirm(sci))
2738		nilfs_segctor_write_out(sci);
2739
2740	if (!list_empty(&sci->sc_dirty_files)) {
2741		nilfs_msg(sci->sc_super, KERN_WARNING,
2742			  "disposed unprocessed dirty file(s) when stopping log writer");
2743		nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2744	}
2745
2746	if (!list_empty(&sci->sc_iput_queue)) {
2747		nilfs_msg(sci->sc_super, KERN_WARNING,
2748			  "disposed unprocessed inode(s) in iput queue when stopping log writer");
2749		nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 1);
2750	}
2751
2752	WARN_ON(!list_empty(&sci->sc_segbufs));
2753	WARN_ON(!list_empty(&sci->sc_write_logs));
2754
2755	nilfs_put_root(sci->sc_root);
2756
2757	down_write(&nilfs->ns_segctor_sem);
2758
2759	del_timer_sync(&sci->sc_timer);
2760	kfree(sci);
2761}
2762
2763/**
2764 * nilfs_attach_log_writer - attach log writer
2765 * @sb: super block instance
2766 * @root: root object of the current filesystem tree
2767 *
2768 * This allocates a log writer object, initializes it, and starts the
2769 * log writer.
2770 *
2771 * Return Value: On success, 0 is returned. On error, one of the following
2772 * negative error code is returned.
2773 *
2774 * %-ENOMEM - Insufficient memory available.
2775 */
2776int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
2777{
2778	struct the_nilfs *nilfs = sb->s_fs_info;
2779	int err;
2780
2781	if (nilfs->ns_writer) {
2782		/*
2783		 * This happens if the filesystem was remounted
2784		 * read/write after nilfs_error degenerated it into a
2785		 * read-only mount.
2786		 */
2787		nilfs_detach_log_writer(sb);
2788	}
2789
2790	nilfs->ns_writer = nilfs_segctor_new(sb, root);
2791	if (!nilfs->ns_writer)
2792		return -ENOMEM;
2793
2794	err = nilfs_segctor_start_thread(nilfs->ns_writer);
2795	if (err) {
2796		kfree(nilfs->ns_writer);
2797		nilfs->ns_writer = NULL;
2798	}
2799	return err;
2800}
2801
2802/**
2803 * nilfs_detach_log_writer - destroy log writer
2804 * @sb: super block instance
2805 *
2806 * This kills log writer daemon, frees the log writer object, and
2807 * destroys list of dirty files.
2808 */
2809void nilfs_detach_log_writer(struct super_block *sb)
2810{
2811	struct the_nilfs *nilfs = sb->s_fs_info;
2812	LIST_HEAD(garbage_list);
2813
2814	down_write(&nilfs->ns_segctor_sem);
2815	if (nilfs->ns_writer) {
2816		nilfs_segctor_destroy(nilfs->ns_writer);
2817		nilfs->ns_writer = NULL;
2818	}
2819
2820	/* Force to free the list of dirty files */
2821	spin_lock(&nilfs->ns_inode_lock);
2822	if (!list_empty(&nilfs->ns_dirty_files)) {
2823		list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2824		nilfs_msg(sb, KERN_WARNING,
2825			  "disposed unprocessed dirty file(s) when detaching log writer");
2826	}
2827	spin_unlock(&nilfs->ns_inode_lock);
2828	up_write(&nilfs->ns_segctor_sem);
2829
2830	nilfs_dispose_list(nilfs, &garbage_list, 1);
2831}