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v6.8
   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * NILFS segment constructor.
   4 *
   5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6 *
   7 * Written by Ryusuke Konishi.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   8 *
   9 */
  10
  11#include <linux/pagemap.h>
  12#include <linux/buffer_head.h>
  13#include <linux/writeback.h>
  14#include <linux/bitops.h>
  15#include <linux/bio.h>
  16#include <linux/completion.h>
  17#include <linux/blkdev.h>
  18#include <linux/backing-dev.h>
  19#include <linux/freezer.h>
  20#include <linux/kthread.h>
  21#include <linux/crc32.h>
  22#include <linux/pagevec.h>
  23#include <linux/slab.h>
  24#include <linux/sched/signal.h>
  25
  26#include "nilfs.h"
  27#include "btnode.h"
  28#include "page.h"
  29#include "segment.h"
  30#include "sufile.h"
  31#include "cpfile.h"
  32#include "ifile.h"
  33#include "segbuf.h"
  34
  35
  36/*
  37 * Segment constructor
  38 */
  39#define SC_N_INODEVEC	16   /* Size of locally allocated inode vector */
  40
  41#define SC_MAX_SEGDELTA 64   /*
  42			      * Upper limit of the number of segments
  43			      * appended in collection retry loop
  44			      */
  45
  46/* Construction mode */
  47enum {
  48	SC_LSEG_SR = 1,	/* Make a logical segment having a super root */
  49	SC_LSEG_DSYNC,	/*
  50			 * Flush data blocks of a given file and make
  51			 * a logical segment without a super root.
  52			 */
  53	SC_FLUSH_FILE,	/*
  54			 * Flush data files, leads to segment writes without
  55			 * creating a checkpoint.
  56			 */
  57	SC_FLUSH_DAT,	/*
  58			 * Flush DAT file.  This also creates segments
  59			 * without a checkpoint.
  60			 */
  61};
  62
  63/* Stage numbers of dirty block collection */
  64enum {
  65	NILFS_ST_INIT = 0,
  66	NILFS_ST_GC,		/* Collecting dirty blocks for GC */
  67	NILFS_ST_FILE,
  68	NILFS_ST_IFILE,
  69	NILFS_ST_CPFILE,
  70	NILFS_ST_SUFILE,
  71	NILFS_ST_DAT,
  72	NILFS_ST_SR,		/* Super root */
  73	NILFS_ST_DSYNC,		/* Data sync blocks */
  74	NILFS_ST_DONE,
  75};
  76
  77#define CREATE_TRACE_POINTS
  78#include <trace/events/nilfs2.h>
  79
  80/*
  81 * nilfs_sc_cstage_inc(), nilfs_sc_cstage_set(), nilfs_sc_cstage_get() are
  82 * wrapper functions of stage count (nilfs_sc_info->sc_stage.scnt). Users of
  83 * the variable must use them because transition of stage count must involve
  84 * trace events (trace_nilfs2_collection_stage_transition).
  85 *
  86 * nilfs_sc_cstage_get() isn't required for the above purpose because it doesn't
  87 * produce tracepoint events. It is provided just for making the intention
  88 * clear.
  89 */
  90static inline void nilfs_sc_cstage_inc(struct nilfs_sc_info *sci)
  91{
  92	sci->sc_stage.scnt++;
  93	trace_nilfs2_collection_stage_transition(sci);
  94}
  95
  96static inline void nilfs_sc_cstage_set(struct nilfs_sc_info *sci, int next_scnt)
  97{
  98	sci->sc_stage.scnt = next_scnt;
  99	trace_nilfs2_collection_stage_transition(sci);
 100}
 101
 102static inline int nilfs_sc_cstage_get(struct nilfs_sc_info *sci)
 103{
 104	return sci->sc_stage.scnt;
 105}
 106
 107/* State flags of collection */
 108#define NILFS_CF_NODE		0x0001	/* Collecting node blocks */
 109#define NILFS_CF_IFILE_STARTED	0x0002	/* IFILE stage has started */
 110#define NILFS_CF_SUFREED	0x0004	/* segment usages has been freed */
 111#define NILFS_CF_HISTORY_MASK	(NILFS_CF_IFILE_STARTED | NILFS_CF_SUFREED)
 112
 113/* Operations depending on the construction mode and file type */
 114struct nilfs_sc_operations {
 115	int (*collect_data)(struct nilfs_sc_info *, struct buffer_head *,
 116			    struct inode *);
 117	int (*collect_node)(struct nilfs_sc_info *, struct buffer_head *,
 118			    struct inode *);
 119	int (*collect_bmap)(struct nilfs_sc_info *, struct buffer_head *,
 120			    struct inode *);
 121	void (*write_data_binfo)(struct nilfs_sc_info *,
 122				 struct nilfs_segsum_pointer *,
 123				 union nilfs_binfo *);
 124	void (*write_node_binfo)(struct nilfs_sc_info *,
 125				 struct nilfs_segsum_pointer *,
 126				 union nilfs_binfo *);
 127};
 128
 129/*
 130 * Other definitions
 131 */
 132static void nilfs_segctor_start_timer(struct nilfs_sc_info *);
 133static void nilfs_segctor_do_flush(struct nilfs_sc_info *, int);
 134static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *);
 135static void nilfs_dispose_list(struct the_nilfs *, struct list_head *, int);
 136
 
 
 
 137#define nilfs_cnt32_ge(a, b)   \
 138	(typecheck(__u32, a) && typecheck(__u32, b) && \
 139	 ((__s32)(a) - (__s32)(b) >= 0))
 
 
 140
 141static int nilfs_prepare_segment_lock(struct super_block *sb,
 142				      struct nilfs_transaction_info *ti)
 143{
 144	struct nilfs_transaction_info *cur_ti = current->journal_info;
 145	void *save = NULL;
 146
 147	if (cur_ti) {
 148		if (cur_ti->ti_magic == NILFS_TI_MAGIC)
 149			return ++cur_ti->ti_count;
 150
 151		/*
 152		 * If journal_info field is occupied by other FS,
 153		 * it is saved and will be restored on
 154		 * nilfs_transaction_commit().
 155		 */
 156		nilfs_warn(sb, "journal info from a different FS");
 157		save = current->journal_info;
 
 
 
 158	}
 159	if (!ti) {
 160		ti = kmem_cache_alloc(nilfs_transaction_cachep, GFP_NOFS);
 161		if (!ti)
 162			return -ENOMEM;
 163		ti->ti_flags = NILFS_TI_DYNAMIC_ALLOC;
 164	} else {
 165		ti->ti_flags = 0;
 166	}
 167	ti->ti_count = 0;
 168	ti->ti_save = save;
 169	ti->ti_magic = NILFS_TI_MAGIC;
 170	current->journal_info = ti;
 171	return 0;
 172}
 173
 174/**
 175 * nilfs_transaction_begin - start indivisible file operations.
 176 * @sb: super block
 177 * @ti: nilfs_transaction_info
 178 * @vacancy_check: flags for vacancy rate checks
 179 *
 180 * nilfs_transaction_begin() acquires a reader/writer semaphore, called
 181 * the segment semaphore, to make a segment construction and write tasks
 182 * exclusive.  The function is used with nilfs_transaction_commit() in pairs.
 183 * The region enclosed by these two functions can be nested.  To avoid a
 184 * deadlock, the semaphore is only acquired or released in the outermost call.
 185 *
 186 * This function allocates a nilfs_transaction_info struct to keep context
 187 * information on it.  It is initialized and hooked onto the current task in
 188 * the outermost call.  If a pre-allocated struct is given to @ti, it is used
 189 * instead; otherwise a new struct is assigned from a slab.
 190 *
 191 * When @vacancy_check flag is set, this function will check the amount of
 192 * free space, and will wait for the GC to reclaim disk space if low capacity.
 193 *
 194 * Return Value: On success, 0 is returned. On error, one of the following
 195 * negative error code is returned.
 196 *
 197 * %-ENOMEM - Insufficient memory available.
 198 *
 199 * %-ENOSPC - No space left on device
 200 */
 201int nilfs_transaction_begin(struct super_block *sb,
 202			    struct nilfs_transaction_info *ti,
 203			    int vacancy_check)
 204{
 205	struct the_nilfs *nilfs;
 206	int ret = nilfs_prepare_segment_lock(sb, ti);
 207	struct nilfs_transaction_info *trace_ti;
 208
 209	if (unlikely(ret < 0))
 210		return ret;
 211	if (ret > 0) {
 212		trace_ti = current->journal_info;
 213
 214		trace_nilfs2_transaction_transition(sb, trace_ti,
 215				    trace_ti->ti_count, trace_ti->ti_flags,
 216				    TRACE_NILFS2_TRANSACTION_BEGIN);
 217		return 0;
 218	}
 219
 220	sb_start_intwrite(sb);
 221
 222	nilfs = sb->s_fs_info;
 223	down_read(&nilfs->ns_segctor_sem);
 224	if (vacancy_check && nilfs_near_disk_full(nilfs)) {
 225		up_read(&nilfs->ns_segctor_sem);
 226		ret = -ENOSPC;
 227		goto failed;
 228	}
 229
 230	trace_ti = current->journal_info;
 231	trace_nilfs2_transaction_transition(sb, trace_ti, trace_ti->ti_count,
 232					    trace_ti->ti_flags,
 233					    TRACE_NILFS2_TRANSACTION_BEGIN);
 234	return 0;
 235
 236 failed:
 237	ti = current->journal_info;
 238	current->journal_info = ti->ti_save;
 239	if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 240		kmem_cache_free(nilfs_transaction_cachep, ti);
 241	sb_end_intwrite(sb);
 242	return ret;
 243}
 244
 245/**
 246 * nilfs_transaction_commit - commit indivisible file operations.
 247 * @sb: super block
 248 *
 249 * nilfs_transaction_commit() releases the read semaphore which is
 250 * acquired by nilfs_transaction_begin(). This is only performed
 251 * in outermost call of this function.  If a commit flag is set,
 252 * nilfs_transaction_commit() sets a timer to start the segment
 253 * constructor.  If a sync flag is set, it starts construction
 254 * directly.
 255 */
 256int nilfs_transaction_commit(struct super_block *sb)
 257{
 258	struct nilfs_transaction_info *ti = current->journal_info;
 259	struct the_nilfs *nilfs = sb->s_fs_info;
 260	int err = 0;
 261
 262	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 263	ti->ti_flags |= NILFS_TI_COMMIT;
 264	if (ti->ti_count > 0) {
 265		ti->ti_count--;
 266		trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 267			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
 268		return 0;
 269	}
 270	if (nilfs->ns_writer) {
 271		struct nilfs_sc_info *sci = nilfs->ns_writer;
 272
 273		if (ti->ti_flags & NILFS_TI_COMMIT)
 274			nilfs_segctor_start_timer(sci);
 275		if (atomic_read(&nilfs->ns_ndirtyblks) > sci->sc_watermark)
 276			nilfs_segctor_do_flush(sci, 0);
 277	}
 278	up_read(&nilfs->ns_segctor_sem);
 279	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 280			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
 281
 282	current->journal_info = ti->ti_save;
 283
 284	if (ti->ti_flags & NILFS_TI_SYNC)
 285		err = nilfs_construct_segment(sb);
 286	if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 287		kmem_cache_free(nilfs_transaction_cachep, ti);
 288	sb_end_intwrite(sb);
 289	return err;
 290}
 291
 292void nilfs_transaction_abort(struct super_block *sb)
 293{
 294	struct nilfs_transaction_info *ti = current->journal_info;
 295	struct the_nilfs *nilfs = sb->s_fs_info;
 296
 297	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 298	if (ti->ti_count > 0) {
 299		ti->ti_count--;
 300		trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 301			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
 302		return;
 303	}
 304	up_read(&nilfs->ns_segctor_sem);
 305
 306	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 307		    ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
 308
 309	current->journal_info = ti->ti_save;
 310	if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 311		kmem_cache_free(nilfs_transaction_cachep, ti);
 312	sb_end_intwrite(sb);
 313}
 314
 315void nilfs_relax_pressure_in_lock(struct super_block *sb)
 316{
 317	struct the_nilfs *nilfs = sb->s_fs_info;
 318	struct nilfs_sc_info *sci = nilfs->ns_writer;
 319
 320	if (sb_rdonly(sb) || unlikely(!sci) || !sci->sc_flush_request)
 321		return;
 322
 323	set_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
 324	up_read(&nilfs->ns_segctor_sem);
 325
 326	down_write(&nilfs->ns_segctor_sem);
 327	if (sci->sc_flush_request &&
 328	    test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags)) {
 329		struct nilfs_transaction_info *ti = current->journal_info;
 330
 331		ti->ti_flags |= NILFS_TI_WRITER;
 332		nilfs_segctor_do_immediate_flush(sci);
 333		ti->ti_flags &= ~NILFS_TI_WRITER;
 334	}
 335	downgrade_write(&nilfs->ns_segctor_sem);
 336}
 337
 338static void nilfs_transaction_lock(struct super_block *sb,
 339				   struct nilfs_transaction_info *ti,
 340				   int gcflag)
 341{
 342	struct nilfs_transaction_info *cur_ti = current->journal_info;
 343	struct the_nilfs *nilfs = sb->s_fs_info;
 344	struct nilfs_sc_info *sci = nilfs->ns_writer;
 345
 346	WARN_ON(cur_ti);
 347	ti->ti_flags = NILFS_TI_WRITER;
 348	ti->ti_count = 0;
 349	ti->ti_save = cur_ti;
 350	ti->ti_magic = NILFS_TI_MAGIC;
 
 351	current->journal_info = ti;
 352
 353	for (;;) {
 354		trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 355			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_TRYLOCK);
 356
 357		down_write(&nilfs->ns_segctor_sem);
 358		if (!test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags))
 359			break;
 360
 361		nilfs_segctor_do_immediate_flush(sci);
 362
 363		up_write(&nilfs->ns_segctor_sem);
 364		cond_resched();
 365	}
 366	if (gcflag)
 367		ti->ti_flags |= NILFS_TI_GC;
 368
 369	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 370			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_LOCK);
 371}
 372
 373static void nilfs_transaction_unlock(struct super_block *sb)
 374{
 375	struct nilfs_transaction_info *ti = current->journal_info;
 376	struct the_nilfs *nilfs = sb->s_fs_info;
 377
 378	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 379	BUG_ON(ti->ti_count > 0);
 380
 381	up_write(&nilfs->ns_segctor_sem);
 382	current->journal_info = ti->ti_save;
 383
 384	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
 385			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_UNLOCK);
 386}
 387
 388static void *nilfs_segctor_map_segsum_entry(struct nilfs_sc_info *sci,
 389					    struct nilfs_segsum_pointer *ssp,
 390					    unsigned int bytes)
 391{
 392	struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 393	unsigned int blocksize = sci->sc_super->s_blocksize;
 394	void *p;
 395
 396	if (unlikely(ssp->offset + bytes > blocksize)) {
 397		ssp->offset = 0;
 398		BUG_ON(NILFS_SEGBUF_BH_IS_LAST(ssp->bh,
 399					       &segbuf->sb_segsum_buffers));
 400		ssp->bh = NILFS_SEGBUF_NEXT_BH(ssp->bh);
 401	}
 402	p = ssp->bh->b_data + ssp->offset;
 403	ssp->offset += bytes;
 404	return p;
 405}
 406
 407/**
 408 * nilfs_segctor_reset_segment_buffer - reset the current segment buffer
 409 * @sci: nilfs_sc_info
 410 */
 411static int nilfs_segctor_reset_segment_buffer(struct nilfs_sc_info *sci)
 412{
 413	struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 414	struct buffer_head *sumbh;
 415	unsigned int sumbytes;
 416	unsigned int flags = 0;
 417	int err;
 418
 419	if (nilfs_doing_gc())
 420		flags = NILFS_SS_GC;
 421	err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime, sci->sc_cno);
 422	if (unlikely(err))
 423		return err;
 424
 425	sumbh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
 426	sumbytes = segbuf->sb_sum.sumbytes;
 427	sci->sc_finfo_ptr.bh = sumbh;  sci->sc_finfo_ptr.offset = sumbytes;
 428	sci->sc_binfo_ptr.bh = sumbh;  sci->sc_binfo_ptr.offset = sumbytes;
 429	sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 430	return 0;
 431}
 432
 433/**
 434 * nilfs_segctor_zeropad_segsum - zero pad the rest of the segment summary area
 435 * @sci: segment constructor object
 436 *
 437 * nilfs_segctor_zeropad_segsum() zero-fills unallocated space at the end of
 438 * the current segment summary block.
 439 */
 440static void nilfs_segctor_zeropad_segsum(struct nilfs_sc_info *sci)
 441{
 442	struct nilfs_segsum_pointer *ssp;
 443
 444	ssp = sci->sc_blk_cnt > 0 ? &sci->sc_binfo_ptr : &sci->sc_finfo_ptr;
 445	if (ssp->offset < ssp->bh->b_size)
 446		memset(ssp->bh->b_data + ssp->offset, 0,
 447		       ssp->bh->b_size - ssp->offset);
 448}
 449
 450static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
 451{
 452	sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
 453	if (NILFS_SEGBUF_IS_LAST(sci->sc_curseg, &sci->sc_segbufs))
 454		return -E2BIG; /*
 455				* The current segment is filled up
 456				* (internal code)
 457				*/
 458	nilfs_segctor_zeropad_segsum(sci);
 459	sci->sc_curseg = NILFS_NEXT_SEGBUF(sci->sc_curseg);
 460	return nilfs_segctor_reset_segment_buffer(sci);
 461}
 462
 463static int nilfs_segctor_add_super_root(struct nilfs_sc_info *sci)
 464{
 465	struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
 466	int err;
 467
 468	if (segbuf->sb_sum.nblocks >= segbuf->sb_rest_blocks) {
 469		err = nilfs_segctor_feed_segment(sci);
 470		if (err)
 471			return err;
 472		segbuf = sci->sc_curseg;
 473	}
 474	err = nilfs_segbuf_extend_payload(segbuf, &segbuf->sb_super_root);
 475	if (likely(!err))
 476		segbuf->sb_sum.flags |= NILFS_SS_SR;
 477	return err;
 478}
 479
 480/*
 481 * Functions for making segment summary and payloads
 482 */
 483static int nilfs_segctor_segsum_block_required(
 484	struct nilfs_sc_info *sci, const struct nilfs_segsum_pointer *ssp,
 485	unsigned int binfo_size)
 486{
 487	unsigned int blocksize = sci->sc_super->s_blocksize;
 488	/* Size of finfo and binfo is enough small against blocksize */
 489
 490	return ssp->offset + binfo_size +
 491		(!sci->sc_blk_cnt ? sizeof(struct nilfs_finfo) : 0) >
 492		blocksize;
 493}
 494
 495static void nilfs_segctor_begin_finfo(struct nilfs_sc_info *sci,
 496				      struct inode *inode)
 497{
 498	sci->sc_curseg->sb_sum.nfinfo++;
 499	sci->sc_binfo_ptr = sci->sc_finfo_ptr;
 500	nilfs_segctor_map_segsum_entry(
 501		sci, &sci->sc_binfo_ptr, sizeof(struct nilfs_finfo));
 502
 503	if (NILFS_I(inode)->i_root &&
 504	    !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 505		set_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
 506	/* skip finfo */
 507}
 508
 509static void nilfs_segctor_end_finfo(struct nilfs_sc_info *sci,
 510				    struct inode *inode)
 511{
 512	struct nilfs_finfo *finfo;
 513	struct nilfs_inode_info *ii;
 514	struct nilfs_segment_buffer *segbuf;
 515	__u64 cno;
 516
 517	if (sci->sc_blk_cnt == 0)
 518		return;
 519
 520	ii = NILFS_I(inode);
 521
 522	if (test_bit(NILFS_I_GCINODE, &ii->i_state))
 523		cno = ii->i_cno;
 524	else if (NILFS_ROOT_METADATA_FILE(inode->i_ino))
 525		cno = 0;
 526	else
 527		cno = sci->sc_cno;
 528
 529	finfo = nilfs_segctor_map_segsum_entry(sci, &sci->sc_finfo_ptr,
 530						 sizeof(*finfo));
 531	finfo->fi_ino = cpu_to_le64(inode->i_ino);
 532	finfo->fi_nblocks = cpu_to_le32(sci->sc_blk_cnt);
 533	finfo->fi_ndatablk = cpu_to_le32(sci->sc_datablk_cnt);
 534	finfo->fi_cno = cpu_to_le64(cno);
 535
 536	segbuf = sci->sc_curseg;
 537	segbuf->sb_sum.sumbytes = sci->sc_binfo_ptr.offset +
 538		sci->sc_super->s_blocksize * (segbuf->sb_sum.nsumblk - 1);
 539	sci->sc_finfo_ptr = sci->sc_binfo_ptr;
 540	sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
 541}
 542
 543static int nilfs_segctor_add_file_block(struct nilfs_sc_info *sci,
 544					struct buffer_head *bh,
 545					struct inode *inode,
 546					unsigned int binfo_size)
 547{
 548	struct nilfs_segment_buffer *segbuf;
 549	int required, err = 0;
 550
 551 retry:
 552	segbuf = sci->sc_curseg;
 553	required = nilfs_segctor_segsum_block_required(
 554		sci, &sci->sc_binfo_ptr, binfo_size);
 555	if (segbuf->sb_sum.nblocks + required + 1 > segbuf->sb_rest_blocks) {
 556		nilfs_segctor_end_finfo(sci, inode);
 557		err = nilfs_segctor_feed_segment(sci);
 558		if (err)
 559			return err;
 560		goto retry;
 561	}
 562	if (unlikely(required)) {
 563		nilfs_segctor_zeropad_segsum(sci);
 564		err = nilfs_segbuf_extend_segsum(segbuf);
 565		if (unlikely(err))
 566			goto failed;
 567	}
 568	if (sci->sc_blk_cnt == 0)
 569		nilfs_segctor_begin_finfo(sci, inode);
 570
 571	nilfs_segctor_map_segsum_entry(sci, &sci->sc_binfo_ptr, binfo_size);
 572	/* Substitution to vblocknr is delayed until update_blocknr() */
 573	nilfs_segbuf_add_file_buffer(segbuf, bh);
 574	sci->sc_blk_cnt++;
 575 failed:
 576	return err;
 577}
 578
 579/*
 580 * Callback functions that enumerate, mark, and collect dirty blocks
 581 */
 582static int nilfs_collect_file_data(struct nilfs_sc_info *sci,
 583				   struct buffer_head *bh, struct inode *inode)
 584{
 585	int err;
 586
 587	err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 588	if (err < 0)
 589		return err;
 590
 591	err = nilfs_segctor_add_file_block(sci, bh, inode,
 592					   sizeof(struct nilfs_binfo_v));
 593	if (!err)
 594		sci->sc_datablk_cnt++;
 595	return err;
 596}
 597
 598static int nilfs_collect_file_node(struct nilfs_sc_info *sci,
 599				   struct buffer_head *bh,
 600				   struct inode *inode)
 601{
 602	return nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 603}
 604
 605static int nilfs_collect_file_bmap(struct nilfs_sc_info *sci,
 606				   struct buffer_head *bh,
 607				   struct inode *inode)
 608{
 609	WARN_ON(!buffer_dirty(bh));
 610	return nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 611}
 612
 613static void nilfs_write_file_data_binfo(struct nilfs_sc_info *sci,
 614					struct nilfs_segsum_pointer *ssp,
 615					union nilfs_binfo *binfo)
 616{
 617	struct nilfs_binfo_v *binfo_v = nilfs_segctor_map_segsum_entry(
 618		sci, ssp, sizeof(*binfo_v));
 619	*binfo_v = binfo->bi_v;
 620}
 621
 622static void nilfs_write_file_node_binfo(struct nilfs_sc_info *sci,
 623					struct nilfs_segsum_pointer *ssp,
 624					union nilfs_binfo *binfo)
 625{
 626	__le64 *vblocknr = nilfs_segctor_map_segsum_entry(
 627		sci, ssp, sizeof(*vblocknr));
 628	*vblocknr = binfo->bi_v.bi_vblocknr;
 629}
 630
 631static const struct nilfs_sc_operations nilfs_sc_file_ops = {
 632	.collect_data = nilfs_collect_file_data,
 633	.collect_node = nilfs_collect_file_node,
 634	.collect_bmap = nilfs_collect_file_bmap,
 635	.write_data_binfo = nilfs_write_file_data_binfo,
 636	.write_node_binfo = nilfs_write_file_node_binfo,
 637};
 638
 639static int nilfs_collect_dat_data(struct nilfs_sc_info *sci,
 640				  struct buffer_head *bh, struct inode *inode)
 641{
 642	int err;
 643
 644	err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
 645	if (err < 0)
 646		return err;
 647
 648	err = nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
 649	if (!err)
 650		sci->sc_datablk_cnt++;
 651	return err;
 652}
 653
 654static int nilfs_collect_dat_bmap(struct nilfs_sc_info *sci,
 655				  struct buffer_head *bh, struct inode *inode)
 656{
 657	WARN_ON(!buffer_dirty(bh));
 658	return nilfs_segctor_add_file_block(sci, bh, inode,
 659					    sizeof(struct nilfs_binfo_dat));
 660}
 661
 662static void nilfs_write_dat_data_binfo(struct nilfs_sc_info *sci,
 663				       struct nilfs_segsum_pointer *ssp,
 664				       union nilfs_binfo *binfo)
 665{
 666	__le64 *blkoff = nilfs_segctor_map_segsum_entry(sci, ssp,
 667							  sizeof(*blkoff));
 668	*blkoff = binfo->bi_dat.bi_blkoff;
 669}
 670
 671static void nilfs_write_dat_node_binfo(struct nilfs_sc_info *sci,
 672				       struct nilfs_segsum_pointer *ssp,
 673				       union nilfs_binfo *binfo)
 674{
 675	struct nilfs_binfo_dat *binfo_dat =
 676		nilfs_segctor_map_segsum_entry(sci, ssp, sizeof(*binfo_dat));
 677	*binfo_dat = binfo->bi_dat;
 678}
 679
 680static const struct nilfs_sc_operations nilfs_sc_dat_ops = {
 681	.collect_data = nilfs_collect_dat_data,
 682	.collect_node = nilfs_collect_file_node,
 683	.collect_bmap = nilfs_collect_dat_bmap,
 684	.write_data_binfo = nilfs_write_dat_data_binfo,
 685	.write_node_binfo = nilfs_write_dat_node_binfo,
 686};
 687
 688static const struct nilfs_sc_operations nilfs_sc_dsync_ops = {
 689	.collect_data = nilfs_collect_file_data,
 690	.collect_node = NULL,
 691	.collect_bmap = NULL,
 692	.write_data_binfo = nilfs_write_file_data_binfo,
 693	.write_node_binfo = NULL,
 694};
 695
 696static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode,
 697					      struct list_head *listp,
 698					      size_t nlimit,
 699					      loff_t start, loff_t end)
 700{
 701	struct address_space *mapping = inode->i_mapping;
 702	struct folio_batch fbatch;
 703	pgoff_t index = 0, last = ULONG_MAX;
 704	size_t ndirties = 0;
 705	int i;
 706
 707	if (unlikely(start != 0 || end != LLONG_MAX)) {
 708		/*
 709		 * A valid range is given for sync-ing data pages. The
 710		 * range is rounded to per-page; extra dirty buffers
 711		 * may be included if blocksize < pagesize.
 712		 */
 713		index = start >> PAGE_SHIFT;
 714		last = end >> PAGE_SHIFT;
 715	}
 716	folio_batch_init(&fbatch);
 717 repeat:
 718	if (unlikely(index > last) ||
 719	      !filemap_get_folios_tag(mapping, &index, last,
 720		      PAGECACHE_TAG_DIRTY, &fbatch))
 
 721		return ndirties;
 722
 723	for (i = 0; i < folio_batch_count(&fbatch); i++) {
 724		struct buffer_head *bh, *head;
 725		struct folio *folio = fbatch.folios[i];
 726
 727		folio_lock(folio);
 728		if (unlikely(folio->mapping != mapping)) {
 729			/* Exclude folios removed from the address space */
 730			folio_unlock(folio);
 731			continue;
 732		}
 733		head = folio_buffers(folio);
 734		if (!head)
 735			head = create_empty_buffers(folio,
 736					i_blocksize(inode), 0);
 737		folio_unlock(folio);
 738
 739		bh = head;
 
 
 
 
 
 740		do {
 741			if (!buffer_dirty(bh) || buffer_async_write(bh))
 742				continue;
 743			get_bh(bh);
 744			list_add_tail(&bh->b_assoc_buffers, listp);
 745			ndirties++;
 746			if (unlikely(ndirties >= nlimit)) {
 747				folio_batch_release(&fbatch);
 748				cond_resched();
 749				return ndirties;
 750			}
 751		} while (bh = bh->b_this_page, bh != head);
 752	}
 753	folio_batch_release(&fbatch);
 754	cond_resched();
 755	goto repeat;
 756}
 757
 758static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
 759					    struct list_head *listp)
 760{
 761	struct nilfs_inode_info *ii = NILFS_I(inode);
 762	struct inode *btnc_inode = ii->i_assoc_inode;
 763	struct folio_batch fbatch;
 764	struct buffer_head *bh, *head;
 765	unsigned int i;
 766	pgoff_t index = 0;
 767
 768	if (!btnc_inode)
 769		return;
 770	folio_batch_init(&fbatch);
 771
 772	while (filemap_get_folios_tag(btnc_inode->i_mapping, &index,
 773				(pgoff_t)-1, PAGECACHE_TAG_DIRTY, &fbatch)) {
 774		for (i = 0; i < folio_batch_count(&fbatch); i++) {
 775			bh = head = folio_buffers(fbatch.folios[i]);
 776			do {
 777				if (buffer_dirty(bh) &&
 778						!buffer_async_write(bh)) {
 779					get_bh(bh);
 780					list_add_tail(&bh->b_assoc_buffers,
 781						      listp);
 782				}
 783				bh = bh->b_this_page;
 784			} while (bh != head);
 785		}
 786		folio_batch_release(&fbatch);
 787		cond_resched();
 788	}
 789}
 790
 791static void nilfs_dispose_list(struct the_nilfs *nilfs,
 792			       struct list_head *head, int force)
 793{
 794	struct nilfs_inode_info *ii, *n;
 795	struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
 796	unsigned int nv = 0;
 797
 798	while (!list_empty(head)) {
 799		spin_lock(&nilfs->ns_inode_lock);
 800		list_for_each_entry_safe(ii, n, head, i_dirty) {
 801			list_del_init(&ii->i_dirty);
 802			if (force) {
 803				if (unlikely(ii->i_bh)) {
 804					brelse(ii->i_bh);
 805					ii->i_bh = NULL;
 806				}
 807			} else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
 808				set_bit(NILFS_I_QUEUED, &ii->i_state);
 809				list_add_tail(&ii->i_dirty,
 810					      &nilfs->ns_dirty_files);
 811				continue;
 812			}
 813			ivec[nv++] = ii;
 814			if (nv == SC_N_INODEVEC)
 815				break;
 816		}
 817		spin_unlock(&nilfs->ns_inode_lock);
 818
 819		for (pii = ivec; nv > 0; pii++, nv--)
 820			iput(&(*pii)->vfs_inode);
 821	}
 822}
 823
 824static void nilfs_iput_work_func(struct work_struct *work)
 825{
 826	struct nilfs_sc_info *sci = container_of(work, struct nilfs_sc_info,
 827						 sc_iput_work);
 828	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 829
 830	nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 0);
 831}
 832
 833static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
 834				     struct nilfs_root *root)
 835{
 836	int ret = 0;
 837
 838	if (nilfs_mdt_fetch_dirty(root->ifile))
 839		ret++;
 840	if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
 841		ret++;
 842	if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
 843		ret++;
 844	if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
 845		ret++;
 846	return ret;
 847}
 848
 849static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 850{
 851	return list_empty(&sci->sc_dirty_files) &&
 852		!test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
 853		sci->sc_nfreesegs == 0 &&
 854		(!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
 855}
 856
 857static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 858{
 859	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 860	int ret = 0;
 861
 862	if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
 863		set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
 864
 865	spin_lock(&nilfs->ns_inode_lock);
 866	if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
 867		ret++;
 868
 869	spin_unlock(&nilfs->ns_inode_lock);
 870	return ret;
 871}
 872
 873static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 874{
 875	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 876
 877	nilfs_mdt_clear_dirty(sci->sc_root->ifile);
 878	nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
 879	nilfs_mdt_clear_dirty(nilfs->ns_sufile);
 880	nilfs_mdt_clear_dirty(nilfs->ns_dat);
 881}
 882
 883static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
 884{
 885	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 886	struct buffer_head *bh_cp;
 887	struct nilfs_checkpoint *raw_cp;
 888	int err;
 889
 890	/* XXX: this interface will be changed */
 891	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 1,
 892					  &raw_cp, &bh_cp);
 893	if (likely(!err)) {
 894		/*
 895		 * The following code is duplicated with cpfile.  But, it is
 896		 * needed to collect the checkpoint even if it was not newly
 897		 * created.
 898		 */
 899		mark_buffer_dirty(bh_cp);
 900		nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
 901		nilfs_cpfile_put_checkpoint(
 902			nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 903	} else if (err == -EINVAL || err == -ENOENT) {
 904		nilfs_error(sci->sc_super,
 905			    "checkpoint creation failed due to metadata corruption.");
 906		err = -EIO;
 907	}
 908	return err;
 909}
 910
 911static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
 912{
 913	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 914	struct buffer_head *bh_cp;
 915	struct nilfs_checkpoint *raw_cp;
 916	int err;
 917
 918	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
 919					  &raw_cp, &bh_cp);
 920	if (unlikely(err)) {
 921		if (err == -EINVAL || err == -ENOENT) {
 922			nilfs_error(sci->sc_super,
 923				    "checkpoint finalization failed due to metadata corruption.");
 924			err = -EIO;
 925		}
 926		goto failed_ibh;
 927	}
 928	raw_cp->cp_snapshot_list.ssl_next = 0;
 929	raw_cp->cp_snapshot_list.ssl_prev = 0;
 930	raw_cp->cp_inodes_count =
 931		cpu_to_le64(atomic64_read(&sci->sc_root->inodes_count));
 932	raw_cp->cp_blocks_count =
 933		cpu_to_le64(atomic64_read(&sci->sc_root->blocks_count));
 934	raw_cp->cp_nblk_inc =
 935		cpu_to_le64(sci->sc_nblk_inc + sci->sc_nblk_this_inc);
 936	raw_cp->cp_create = cpu_to_le64(sci->sc_seg_ctime);
 937	raw_cp->cp_cno = cpu_to_le64(nilfs->ns_cno);
 938
 939	if (test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 940		nilfs_checkpoint_clear_minor(raw_cp);
 941	else
 942		nilfs_checkpoint_set_minor(raw_cp);
 943
 944	nilfs_write_inode_common(sci->sc_root->ifile,
 945				 &raw_cp->cp_ifile_inode, 1);
 946	nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 947	return 0;
 948
 949 failed_ibh:
 950	return err;
 951}
 952
 953static void nilfs_fill_in_file_bmap(struct inode *ifile,
 954				    struct nilfs_inode_info *ii)
 955
 956{
 957	struct buffer_head *ibh;
 958	struct nilfs_inode *raw_inode;
 959
 960	if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
 961		ibh = ii->i_bh;
 962		BUG_ON(!ibh);
 963		raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
 964						  ibh);
 965		nilfs_bmap_write(ii->i_bmap, raw_inode);
 966		nilfs_ifile_unmap_inode(ifile, ii->vfs_inode.i_ino, ibh);
 967	}
 968}
 969
 970static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
 971{
 972	struct nilfs_inode_info *ii;
 973
 974	list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
 975		nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
 976		set_bit(NILFS_I_COLLECTED, &ii->i_state);
 977	}
 978}
 979
 980static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 981					     struct the_nilfs *nilfs)
 982{
 983	struct buffer_head *bh_sr;
 984	struct nilfs_super_root *raw_sr;
 985	unsigned int isz, srsz;
 986
 987	bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
 988
 989	lock_buffer(bh_sr);
 990	raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 991	isz = nilfs->ns_inode_size;
 992	srsz = NILFS_SR_BYTES(isz);
 993
 994	raw_sr->sr_sum = 0;  /* Ensure initialization within this update */
 995	raw_sr->sr_bytes = cpu_to_le16(srsz);
 996	raw_sr->sr_nongc_ctime
 997		= cpu_to_le64(nilfs_doing_gc() ?
 998			      nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
 999	raw_sr->sr_flags = 0;
1000
1001	nilfs_write_inode_common(nilfs->ns_dat, (void *)raw_sr +
1002				 NILFS_SR_DAT_OFFSET(isz), 1);
1003	nilfs_write_inode_common(nilfs->ns_cpfile, (void *)raw_sr +
1004				 NILFS_SR_CPFILE_OFFSET(isz), 1);
1005	nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
1006				 NILFS_SR_SUFILE_OFFSET(isz), 1);
1007	memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
1008	set_buffer_uptodate(bh_sr);
1009	unlock_buffer(bh_sr);
1010}
1011
1012static void nilfs_redirty_inodes(struct list_head *head)
1013{
1014	struct nilfs_inode_info *ii;
1015
1016	list_for_each_entry(ii, head, i_dirty) {
1017		if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
1018			clear_bit(NILFS_I_COLLECTED, &ii->i_state);
1019	}
1020}
1021
1022static void nilfs_drop_collected_inodes(struct list_head *head)
1023{
1024	struct nilfs_inode_info *ii;
1025
1026	list_for_each_entry(ii, head, i_dirty) {
1027		if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
1028			continue;
1029
1030		clear_bit(NILFS_I_INODE_SYNC, &ii->i_state);
1031		set_bit(NILFS_I_UPDATED, &ii->i_state);
1032	}
1033}
1034
1035static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
1036				       struct inode *inode,
1037				       struct list_head *listp,
1038				       int (*collect)(struct nilfs_sc_info *,
1039						      struct buffer_head *,
1040						      struct inode *))
1041{
1042	struct buffer_head *bh, *n;
1043	int err = 0;
1044
1045	if (collect) {
1046		list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
1047			list_del_init(&bh->b_assoc_buffers);
1048			err = collect(sci, bh, inode);
1049			brelse(bh);
1050			if (unlikely(err))
1051				goto dispose_buffers;
1052		}
1053		return 0;
1054	}
1055
1056 dispose_buffers:
1057	while (!list_empty(listp)) {
1058		bh = list_first_entry(listp, struct buffer_head,
1059				      b_assoc_buffers);
1060		list_del_init(&bh->b_assoc_buffers);
1061		brelse(bh);
1062	}
1063	return err;
1064}
1065
1066static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
1067{
1068	/* Remaining number of blocks within segment buffer */
1069	return sci->sc_segbuf_nblocks -
1070		(sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
1071}
1072
1073static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
1074				   struct inode *inode,
1075				   const struct nilfs_sc_operations *sc_ops)
1076{
1077	LIST_HEAD(data_buffers);
1078	LIST_HEAD(node_buffers);
1079	int err;
1080
1081	if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1082		size_t n, rest = nilfs_segctor_buffer_rest(sci);
1083
1084		n = nilfs_lookup_dirty_data_buffers(
1085			inode, &data_buffers, rest + 1, 0, LLONG_MAX);
1086		if (n > rest) {
1087			err = nilfs_segctor_apply_buffers(
1088				sci, inode, &data_buffers,
1089				sc_ops->collect_data);
1090			BUG_ON(!err); /* always receive -E2BIG or true error */
1091			goto break_or_fail;
1092		}
1093	}
1094	nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
1095
1096	if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1097		err = nilfs_segctor_apply_buffers(
1098			sci, inode, &data_buffers, sc_ops->collect_data);
1099		if (unlikely(err)) {
1100			/* dispose node list */
1101			nilfs_segctor_apply_buffers(
1102				sci, inode, &node_buffers, NULL);
1103			goto break_or_fail;
1104		}
1105		sci->sc_stage.flags |= NILFS_CF_NODE;
1106	}
1107	/* Collect node */
1108	err = nilfs_segctor_apply_buffers(
1109		sci, inode, &node_buffers, sc_ops->collect_node);
1110	if (unlikely(err))
1111		goto break_or_fail;
1112
1113	nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1114	err = nilfs_segctor_apply_buffers(
1115		sci, inode, &node_buffers, sc_ops->collect_bmap);
1116	if (unlikely(err))
1117		goto break_or_fail;
1118
1119	nilfs_segctor_end_finfo(sci, inode);
1120	sci->sc_stage.flags &= ~NILFS_CF_NODE;
1121
1122 break_or_fail:
1123	return err;
1124}
1125
1126static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1127					 struct inode *inode)
1128{
1129	LIST_HEAD(data_buffers);
1130	size_t n, rest = nilfs_segctor_buffer_rest(sci);
1131	int err;
1132
1133	n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1134					    sci->sc_dsync_start,
1135					    sci->sc_dsync_end);
1136
1137	err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1138					  nilfs_collect_file_data);
1139	if (!err) {
1140		nilfs_segctor_end_finfo(sci, inode);
1141		BUG_ON(n > rest);
1142		/* always receive -E2BIG or true error if n > rest */
1143	}
1144	return err;
1145}
1146
1147static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1148{
1149	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1150	struct list_head *head;
1151	struct nilfs_inode_info *ii;
1152	size_t ndone;
1153	int err = 0;
1154
1155	switch (nilfs_sc_cstage_get(sci)) {
1156	case NILFS_ST_INIT:
1157		/* Pre-processes */
1158		sci->sc_stage.flags = 0;
1159
1160		if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1161			sci->sc_nblk_inc = 0;
1162			sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1163			if (mode == SC_LSEG_DSYNC) {
1164				nilfs_sc_cstage_set(sci, NILFS_ST_DSYNC);
1165				goto dsync_mode;
1166			}
1167		}
1168
1169		sci->sc_stage.dirty_file_ptr = NULL;
1170		sci->sc_stage.gc_inode_ptr = NULL;
1171		if (mode == SC_FLUSH_DAT) {
1172			nilfs_sc_cstage_set(sci, NILFS_ST_DAT);
1173			goto dat_stage;
1174		}
1175		nilfs_sc_cstage_inc(sci);
1176		fallthrough;
1177	case NILFS_ST_GC:
1178		if (nilfs_doing_gc()) {
1179			head = &sci->sc_gc_inodes;
1180			ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1181						head, i_dirty);
1182			list_for_each_entry_continue(ii, head, i_dirty) {
1183				err = nilfs_segctor_scan_file(
1184					sci, &ii->vfs_inode,
1185					&nilfs_sc_file_ops);
1186				if (unlikely(err)) {
1187					sci->sc_stage.gc_inode_ptr = list_entry(
1188						ii->i_dirty.prev,
1189						struct nilfs_inode_info,
1190						i_dirty);
1191					goto break_or_fail;
1192				}
1193				set_bit(NILFS_I_COLLECTED, &ii->i_state);
1194			}
1195			sci->sc_stage.gc_inode_ptr = NULL;
1196		}
1197		nilfs_sc_cstage_inc(sci);
1198		fallthrough;
1199	case NILFS_ST_FILE:
1200		head = &sci->sc_dirty_files;
1201		ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1202					i_dirty);
1203		list_for_each_entry_continue(ii, head, i_dirty) {
1204			clear_bit(NILFS_I_DIRTY, &ii->i_state);
1205
1206			err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1207						      &nilfs_sc_file_ops);
1208			if (unlikely(err)) {
1209				sci->sc_stage.dirty_file_ptr =
1210					list_entry(ii->i_dirty.prev,
1211						   struct nilfs_inode_info,
1212						   i_dirty);
1213				goto break_or_fail;
1214			}
1215			/* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1216			/* XXX: required ? */
1217		}
1218		sci->sc_stage.dirty_file_ptr = NULL;
1219		if (mode == SC_FLUSH_FILE) {
1220			nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1221			return 0;
1222		}
1223		nilfs_sc_cstage_inc(sci);
1224		sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1225		fallthrough;
1226	case NILFS_ST_IFILE:
1227		err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1228					      &nilfs_sc_file_ops);
1229		if (unlikely(err))
1230			break;
1231		nilfs_sc_cstage_inc(sci);
1232		/* Creating a checkpoint */
1233		err = nilfs_segctor_create_checkpoint(sci);
1234		if (unlikely(err))
1235			break;
1236		fallthrough;
1237	case NILFS_ST_CPFILE:
1238		err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1239					      &nilfs_sc_file_ops);
1240		if (unlikely(err))
1241			break;
1242		nilfs_sc_cstage_inc(sci);
1243		fallthrough;
1244	case NILFS_ST_SUFILE:
1245		err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1246					 sci->sc_nfreesegs, &ndone);
1247		if (unlikely(err)) {
1248			nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1249						  sci->sc_freesegs, ndone,
1250						  NULL);
1251			break;
1252		}
1253		sci->sc_stage.flags |= NILFS_CF_SUFREED;
1254
1255		err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1256					      &nilfs_sc_file_ops);
1257		if (unlikely(err))
1258			break;
1259		nilfs_sc_cstage_inc(sci);
1260		fallthrough;
1261	case NILFS_ST_DAT:
1262 dat_stage:
1263		err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1264					      &nilfs_sc_dat_ops);
1265		if (unlikely(err))
1266			break;
1267		if (mode == SC_FLUSH_DAT) {
1268			nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1269			return 0;
1270		}
1271		nilfs_sc_cstage_inc(sci);
1272		fallthrough;
1273	case NILFS_ST_SR:
1274		if (mode == SC_LSEG_SR) {
1275			/* Appending a super root */
1276			err = nilfs_segctor_add_super_root(sci);
1277			if (unlikely(err))
1278				break;
1279		}
1280		/* End of a logical segment */
1281		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1282		nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1283		return 0;
1284	case NILFS_ST_DSYNC:
1285 dsync_mode:
1286		sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1287		ii = sci->sc_dsync_inode;
1288		if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1289			break;
1290
1291		err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1292		if (unlikely(err))
1293			break;
1294		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1295		nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1296		return 0;
1297	case NILFS_ST_DONE:
1298		return 0;
1299	default:
1300		BUG();
1301	}
1302
1303 break_or_fail:
1304	return err;
1305}
1306
1307/**
1308 * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1309 * @sci: nilfs_sc_info
1310 * @nilfs: nilfs object
1311 */
1312static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1313					    struct the_nilfs *nilfs)
1314{
1315	struct nilfs_segment_buffer *segbuf, *prev;
1316	__u64 nextnum;
1317	int err, alloc = 0;
1318
1319	segbuf = nilfs_segbuf_new(sci->sc_super);
1320	if (unlikely(!segbuf))
1321		return -ENOMEM;
1322
1323	if (list_empty(&sci->sc_write_logs)) {
1324		nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1325				 nilfs->ns_pseg_offset, nilfs);
1326		if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1327			nilfs_shift_to_next_segment(nilfs);
1328			nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1329		}
1330
1331		segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1332		nextnum = nilfs->ns_nextnum;
1333
1334		if (nilfs->ns_segnum == nilfs->ns_nextnum)
1335			/* Start from the head of a new full segment */
1336			alloc++;
1337	} else {
1338		/* Continue logs */
1339		prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1340		nilfs_segbuf_map_cont(segbuf, prev);
1341		segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1342		nextnum = prev->sb_nextnum;
1343
1344		if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1345			nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1346			segbuf->sb_sum.seg_seq++;
1347			alloc++;
1348		}
1349	}
1350
1351	err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1352	if (err)
1353		goto failed;
1354
1355	if (alloc) {
1356		err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1357		if (err)
1358			goto failed;
1359	}
1360	nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1361
1362	BUG_ON(!list_empty(&sci->sc_segbufs));
1363	list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1364	sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1365	return 0;
1366
1367 failed:
1368	nilfs_segbuf_free(segbuf);
1369	return err;
1370}
1371
1372static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1373					 struct the_nilfs *nilfs, int nadd)
1374{
1375	struct nilfs_segment_buffer *segbuf, *prev;
1376	struct inode *sufile = nilfs->ns_sufile;
1377	__u64 nextnextnum;
1378	LIST_HEAD(list);
1379	int err, ret, i;
1380
1381	prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1382	/*
1383	 * Since the segment specified with nextnum might be allocated during
1384	 * the previous construction, the buffer including its segusage may
1385	 * not be dirty.  The following call ensures that the buffer is dirty
1386	 * and will pin the buffer on memory until the sufile is written.
1387	 */
1388	err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1389	if (unlikely(err))
1390		return err;
1391
1392	for (i = 0; i < nadd; i++) {
1393		/* extend segment info */
1394		err = -ENOMEM;
1395		segbuf = nilfs_segbuf_new(sci->sc_super);
1396		if (unlikely(!segbuf))
1397			goto failed;
1398
1399		/* map this buffer to region of segment on-disk */
1400		nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1401		sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1402
1403		/* allocate the next next full segment */
1404		err = nilfs_sufile_alloc(sufile, &nextnextnum);
1405		if (unlikely(err))
1406			goto failed_segbuf;
1407
1408		segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1409		nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1410
1411		list_add_tail(&segbuf->sb_list, &list);
1412		prev = segbuf;
1413	}
1414	list_splice_tail(&list, &sci->sc_segbufs);
1415	return 0;
1416
1417 failed_segbuf:
1418	nilfs_segbuf_free(segbuf);
1419 failed:
1420	list_for_each_entry(segbuf, &list, sb_list) {
1421		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1422		WARN_ON(ret); /* never fails */
1423	}
1424	nilfs_destroy_logs(&list);
1425	return err;
1426}
1427
1428static void nilfs_free_incomplete_logs(struct list_head *logs,
1429				       struct the_nilfs *nilfs)
1430{
1431	struct nilfs_segment_buffer *segbuf, *prev;
1432	struct inode *sufile = nilfs->ns_sufile;
1433	int ret;
1434
1435	segbuf = NILFS_FIRST_SEGBUF(logs);
1436	if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1437		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1438		WARN_ON(ret); /* never fails */
1439	}
1440	if (atomic_read(&segbuf->sb_err)) {
1441		/* Case 1: The first segment failed */
1442		if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1443			/*
1444			 * Case 1a:  Partial segment appended into an existing
1445			 * segment
1446			 */
1447			nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1448						segbuf->sb_fseg_end);
1449		else /* Case 1b:  New full segment */
1450			set_nilfs_discontinued(nilfs);
1451	}
1452
1453	prev = segbuf;
1454	list_for_each_entry_continue(segbuf, logs, sb_list) {
1455		if (prev->sb_nextnum != segbuf->sb_nextnum) {
1456			ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1457			WARN_ON(ret); /* never fails */
1458		}
1459		if (atomic_read(&segbuf->sb_err) &&
1460		    segbuf->sb_segnum != nilfs->ns_nextnum)
1461			/* Case 2: extended segment (!= next) failed */
1462			nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1463		prev = segbuf;
1464	}
1465}
1466
1467static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1468					  struct inode *sufile)
1469{
1470	struct nilfs_segment_buffer *segbuf;
1471	unsigned long live_blocks;
1472	int ret;
1473
1474	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1475		live_blocks = segbuf->sb_sum.nblocks +
1476			(segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1477		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1478						     live_blocks,
1479						     sci->sc_seg_ctime);
1480		WARN_ON(ret); /* always succeed because the segusage is dirty */
1481	}
1482}
1483
1484static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1485{
1486	struct nilfs_segment_buffer *segbuf;
1487	int ret;
1488
1489	segbuf = NILFS_FIRST_SEGBUF(logs);
1490	ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1491					     segbuf->sb_pseg_start -
1492					     segbuf->sb_fseg_start, 0);
1493	WARN_ON(ret); /* always succeed because the segusage is dirty */
1494
1495	list_for_each_entry_continue(segbuf, logs, sb_list) {
1496		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1497						     0, 0);
1498		WARN_ON(ret); /* always succeed */
1499	}
1500}
1501
1502static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1503					    struct nilfs_segment_buffer *last,
1504					    struct inode *sufile)
1505{
1506	struct nilfs_segment_buffer *segbuf = last;
1507	int ret;
1508
1509	list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1510		sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1511		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1512		WARN_ON(ret);
1513	}
1514	nilfs_truncate_logs(&sci->sc_segbufs, last);
1515}
1516
1517
1518static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1519				 struct the_nilfs *nilfs, int mode)
1520{
1521	struct nilfs_cstage prev_stage = sci->sc_stage;
1522	int err, nadd = 1;
1523
1524	/* Collection retry loop */
1525	for (;;) {
1526		sci->sc_nblk_this_inc = 0;
1527		sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1528
1529		err = nilfs_segctor_reset_segment_buffer(sci);
1530		if (unlikely(err))
1531			goto failed;
1532
1533		err = nilfs_segctor_collect_blocks(sci, mode);
1534		sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1535		if (!err)
1536			break;
1537
1538		if (unlikely(err != -E2BIG))
1539			goto failed;
1540
1541		/* The current segment is filled up */
1542		if (mode != SC_LSEG_SR ||
1543		    nilfs_sc_cstage_get(sci) < NILFS_ST_CPFILE)
1544			break;
1545
1546		nilfs_clear_logs(&sci->sc_segbufs);
1547
1548		if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1549			err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1550							sci->sc_freesegs,
1551							sci->sc_nfreesegs,
1552							NULL);
1553			WARN_ON(err); /* do not happen */
1554			sci->sc_stage.flags &= ~NILFS_CF_SUFREED;
1555		}
1556
1557		err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1558		if (unlikely(err))
1559			return err;
1560
1561		nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1562		sci->sc_stage = prev_stage;
1563	}
1564	nilfs_segctor_zeropad_segsum(sci);
1565	nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1566	return 0;
1567
1568 failed:
1569	return err;
1570}
1571
1572static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1573				      struct buffer_head *new_bh)
1574{
1575	BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1576
1577	list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1578	/* The caller must release old_bh */
1579}
1580
1581static int
1582nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1583				     struct nilfs_segment_buffer *segbuf,
1584				     int mode)
1585{
1586	struct inode *inode = NULL;
1587	sector_t blocknr;
1588	unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1589	unsigned long nblocks = 0, ndatablk = 0;
1590	const struct nilfs_sc_operations *sc_op = NULL;
1591	struct nilfs_segsum_pointer ssp;
1592	struct nilfs_finfo *finfo = NULL;
1593	union nilfs_binfo binfo;
1594	struct buffer_head *bh, *bh_org;
1595	ino_t ino = 0;
1596	int err = 0;
1597
1598	if (!nfinfo)
1599		goto out;
1600
1601	blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1602	ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1603	ssp.offset = sizeof(struct nilfs_segment_summary);
1604
1605	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1606		if (bh == segbuf->sb_super_root)
1607			break;
1608		if (!finfo) {
1609			finfo =	nilfs_segctor_map_segsum_entry(
1610				sci, &ssp, sizeof(*finfo));
1611			ino = le64_to_cpu(finfo->fi_ino);
1612			nblocks = le32_to_cpu(finfo->fi_nblocks);
1613			ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1614
1615			inode = bh->b_folio->mapping->host;
1616
1617			if (mode == SC_LSEG_DSYNC)
1618				sc_op = &nilfs_sc_dsync_ops;
1619			else if (ino == NILFS_DAT_INO)
1620				sc_op = &nilfs_sc_dat_ops;
1621			else /* file blocks */
1622				sc_op = &nilfs_sc_file_ops;
1623		}
1624		bh_org = bh;
1625		get_bh(bh_org);
1626		err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1627					&binfo);
1628		if (bh != bh_org)
1629			nilfs_list_replace_buffer(bh_org, bh);
1630		brelse(bh_org);
1631		if (unlikely(err))
1632			goto failed_bmap;
1633
1634		if (ndatablk > 0)
1635			sc_op->write_data_binfo(sci, &ssp, &binfo);
1636		else
1637			sc_op->write_node_binfo(sci, &ssp, &binfo);
1638
1639		blocknr++;
1640		if (--nblocks == 0) {
1641			finfo = NULL;
1642			if (--nfinfo == 0)
1643				break;
1644		} else if (ndatablk > 0)
1645			ndatablk--;
1646	}
1647 out:
1648	return 0;
1649
1650 failed_bmap:
1651	return err;
1652}
1653
1654static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1655{
1656	struct nilfs_segment_buffer *segbuf;
1657	int err;
1658
1659	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1660		err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1661		if (unlikely(err))
1662			return err;
1663		nilfs_segbuf_fill_in_segsum(segbuf);
1664	}
1665	return 0;
1666}
1667
1668static void nilfs_begin_folio_io(struct folio *folio)
1669{
1670	if (!folio || folio_test_writeback(folio))
1671		/*
1672		 * For split b-tree node pages, this function may be called
1673		 * twice.  We ignore the 2nd or later calls by this check.
1674		 */
1675		return;
1676
1677	folio_lock(folio);
1678	folio_clear_dirty_for_io(folio);
1679	folio_start_writeback(folio);
1680	folio_unlock(folio);
1681}
1682
1683static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci)
1684{
1685	struct nilfs_segment_buffer *segbuf;
1686	struct folio *bd_folio = NULL, *fs_folio = NULL;
1687
1688	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1689		struct buffer_head *bh;
1690
1691		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1692				    b_assoc_buffers) {
1693			if (bh->b_folio != bd_folio) {
1694				if (bd_folio) {
1695					folio_lock(bd_folio);
1696					folio_clear_dirty_for_io(bd_folio);
1697					folio_start_writeback(bd_folio);
1698					folio_unlock(bd_folio);
 
1699				}
1700				bd_folio = bh->b_folio;
1701			}
1702		}
1703
1704		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1705				    b_assoc_buffers) {
 
1706			if (bh == segbuf->sb_super_root) {
1707				if (bh->b_folio != bd_folio) {
1708					folio_lock(bd_folio);
1709					folio_clear_dirty_for_io(bd_folio);
1710					folio_start_writeback(bd_folio);
1711					folio_unlock(bd_folio);
1712					bd_folio = bh->b_folio;
1713				}
1714				break;
1715			}
1716			set_buffer_async_write(bh);
1717			if (bh->b_folio != fs_folio) {
1718				nilfs_begin_folio_io(fs_folio);
1719				fs_folio = bh->b_folio;
1720			}
1721		}
1722	}
1723	if (bd_folio) {
1724		folio_lock(bd_folio);
1725		folio_clear_dirty_for_io(bd_folio);
1726		folio_start_writeback(bd_folio);
1727		folio_unlock(bd_folio);
1728	}
1729	nilfs_begin_folio_io(fs_folio);
1730}
1731
1732static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1733			       struct the_nilfs *nilfs)
1734{
1735	int ret;
1736
1737	ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1738	list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1739	return ret;
1740}
1741
1742static void nilfs_end_folio_io(struct folio *folio, int err)
1743{
1744	if (!folio)
1745		return;
1746
1747	if (buffer_nilfs_node(folio_buffers(folio)) &&
1748			!folio_test_writeback(folio)) {
1749		/*
1750		 * For b-tree node pages, this function may be called twice
1751		 * or more because they might be split in a segment.
1752		 */
1753		if (folio_test_dirty(folio)) {
1754			/*
1755			 * For pages holding split b-tree node buffers, dirty
1756			 * flag on the buffers may be cleared discretely.
1757			 * In that case, the page is once redirtied for
1758			 * remaining buffers, and it must be cancelled if
1759			 * all the buffers get cleaned later.
1760			 */
1761			folio_lock(folio);
1762			if (nilfs_folio_buffers_clean(folio))
1763				__nilfs_clear_folio_dirty(folio);
1764			folio_unlock(folio);
1765		}
1766		return;
1767	}
1768
1769	if (!err) {
1770		if (!nilfs_folio_buffers_clean(folio))
1771			filemap_dirty_folio(folio->mapping, folio);
1772		folio_clear_error(folio);
1773	} else {
1774		filemap_dirty_folio(folio->mapping, folio);
1775		folio_set_error(folio);
1776	}
1777
1778	folio_end_writeback(folio);
1779}
1780
1781static void nilfs_abort_logs(struct list_head *logs, int err)
1782{
1783	struct nilfs_segment_buffer *segbuf;
1784	struct folio *bd_folio = NULL, *fs_folio = NULL;
1785	struct buffer_head *bh;
1786
1787	if (list_empty(logs))
1788		return;
1789
1790	list_for_each_entry(segbuf, logs, sb_list) {
1791		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1792				    b_assoc_buffers) {
1793			clear_buffer_uptodate(bh);
1794			if (bh->b_folio != bd_folio) {
1795				if (bd_folio)
1796					folio_end_writeback(bd_folio);
1797				bd_folio = bh->b_folio;
1798			}
1799		}
1800
1801		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1802				    b_assoc_buffers) {
 
1803			if (bh == segbuf->sb_super_root) {
1804				clear_buffer_uptodate(bh);
1805				if (bh->b_folio != bd_folio) {
1806					folio_end_writeback(bd_folio);
1807					bd_folio = bh->b_folio;
1808				}
1809				break;
1810			}
1811			clear_buffer_async_write(bh);
1812			if (bh->b_folio != fs_folio) {
1813				nilfs_end_folio_io(fs_folio, err);
1814				fs_folio = bh->b_folio;
1815			}
1816		}
1817	}
1818	if (bd_folio)
1819		folio_end_writeback(bd_folio);
1820
1821	nilfs_end_folio_io(fs_folio, err);
1822}
1823
1824static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
1825					     struct the_nilfs *nilfs, int err)
1826{
1827	LIST_HEAD(logs);
1828	int ret;
1829
1830	list_splice_tail_init(&sci->sc_write_logs, &logs);
1831	ret = nilfs_wait_on_logs(&logs);
1832	nilfs_abort_logs(&logs, ret ? : err);
1833
1834	list_splice_tail_init(&sci->sc_segbufs, &logs);
1835	nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
1836	nilfs_free_incomplete_logs(&logs, nilfs);
1837
1838	if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1839		ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1840						sci->sc_freesegs,
1841						sci->sc_nfreesegs,
1842						NULL);
1843		WARN_ON(ret); /* do not happen */
1844	}
1845
1846	nilfs_destroy_logs(&logs);
1847}
1848
1849static void nilfs_set_next_segment(struct the_nilfs *nilfs,
1850				   struct nilfs_segment_buffer *segbuf)
1851{
1852	nilfs->ns_segnum = segbuf->sb_segnum;
1853	nilfs->ns_nextnum = segbuf->sb_nextnum;
1854	nilfs->ns_pseg_offset = segbuf->sb_pseg_start - segbuf->sb_fseg_start
1855		+ segbuf->sb_sum.nblocks;
1856	nilfs->ns_seg_seq = segbuf->sb_sum.seg_seq;
1857	nilfs->ns_ctime = segbuf->sb_sum.ctime;
1858}
1859
1860static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
1861{
1862	struct nilfs_segment_buffer *segbuf;
1863	struct folio *bd_folio = NULL, *fs_folio = NULL;
1864	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1865	int update_sr = false;
1866
1867	list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
1868		struct buffer_head *bh;
1869
1870		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1871				    b_assoc_buffers) {
1872			set_buffer_uptodate(bh);
1873			clear_buffer_dirty(bh);
1874			if (bh->b_folio != bd_folio) {
1875				if (bd_folio)
1876					folio_end_writeback(bd_folio);
1877				bd_folio = bh->b_folio;
 
1878			}
1879		}
1880		/*
1881		 * We assume that the buffers which belong to the same folio
1882		 * continue over the buffer list.
1883		 * Under this assumption, the last BHs of folios is
1884		 * identifiable by the discontinuity of bh->b_folio
1885		 * (folio != fs_folio).
1886		 *
1887		 * For B-tree node blocks, however, this assumption is not
1888		 * guaranteed.  The cleanup code of B-tree node folios needs
1889		 * special care.
1890		 */
1891		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1892				    b_assoc_buffers) {
1893			const unsigned long set_bits = BIT(BH_Uptodate);
1894			const unsigned long clear_bits =
1895				(BIT(BH_Dirty) | BIT(BH_Async_Write) |
1896				 BIT(BH_Delay) | BIT(BH_NILFS_Volatile) |
1897				 BIT(BH_NILFS_Redirected));
1898
1899			if (bh == segbuf->sb_super_root) {
1900				set_buffer_uptodate(bh);
1901				clear_buffer_dirty(bh);
1902				if (bh->b_folio != bd_folio) {
1903					folio_end_writeback(bd_folio);
1904					bd_folio = bh->b_folio;
1905				}
1906				update_sr = true;
1907				break;
1908			}
1909			set_mask_bits(&bh->b_state, clear_bits, set_bits);
1910			if (bh->b_folio != fs_folio) {
1911				nilfs_end_folio_io(fs_folio, 0);
1912				fs_folio = bh->b_folio;
1913			}
1914		}
1915
1916		if (!nilfs_segbuf_simplex(segbuf)) {
1917			if (segbuf->sb_sum.flags & NILFS_SS_LOGBGN) {
1918				set_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1919				sci->sc_lseg_stime = jiffies;
1920			}
1921			if (segbuf->sb_sum.flags & NILFS_SS_LOGEND)
1922				clear_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1923		}
1924	}
1925	/*
1926	 * Since folios may continue over multiple segment buffers,
1927	 * end of the last folio must be checked outside of the loop.
1928	 */
1929	if (bd_folio)
1930		folio_end_writeback(bd_folio);
1931
1932	nilfs_end_folio_io(fs_folio, 0);
1933
1934	nilfs_drop_collected_inodes(&sci->sc_dirty_files);
1935
1936	if (nilfs_doing_gc())
1937		nilfs_drop_collected_inodes(&sci->sc_gc_inodes);
1938	else
1939		nilfs->ns_nongc_ctime = sci->sc_seg_ctime;
1940
1941	sci->sc_nblk_inc += sci->sc_nblk_this_inc;
1942
1943	segbuf = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1944	nilfs_set_next_segment(nilfs, segbuf);
1945
1946	if (update_sr) {
1947		nilfs->ns_flushed_device = 0;
1948		nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
1949				       segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
1950
1951		clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
1952		clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1953		set_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1954		nilfs_segctor_clear_metadata_dirty(sci);
1955	} else
1956		clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1957}
1958
1959static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
1960{
1961	int ret;
1962
1963	ret = nilfs_wait_on_logs(&sci->sc_write_logs);
1964	if (!ret) {
1965		nilfs_segctor_complete_write(sci);
1966		nilfs_destroy_logs(&sci->sc_write_logs);
1967	}
1968	return ret;
1969}
1970
1971static int nilfs_segctor_collect_dirty_files(struct nilfs_sc_info *sci,
1972					     struct the_nilfs *nilfs)
1973{
1974	struct nilfs_inode_info *ii, *n;
1975	struct inode *ifile = sci->sc_root->ifile;
1976
1977	spin_lock(&nilfs->ns_inode_lock);
1978 retry:
1979	list_for_each_entry_safe(ii, n, &nilfs->ns_dirty_files, i_dirty) {
1980		if (!ii->i_bh) {
1981			struct buffer_head *ibh;
1982			int err;
1983
1984			spin_unlock(&nilfs->ns_inode_lock);
1985			err = nilfs_ifile_get_inode_block(
1986				ifile, ii->vfs_inode.i_ino, &ibh);
1987			if (unlikely(err)) {
1988				nilfs_warn(sci->sc_super,
1989					   "log writer: error %d getting inode block (ino=%lu)",
1990					   err, ii->vfs_inode.i_ino);
1991				return err;
1992			}
 
 
1993			spin_lock(&nilfs->ns_inode_lock);
1994			if (likely(!ii->i_bh))
1995				ii->i_bh = ibh;
1996			else
1997				brelse(ibh);
1998			goto retry;
1999		}
2000
2001		// Always redirty the buffer to avoid race condition
2002		mark_buffer_dirty(ii->i_bh);
2003		nilfs_mdt_mark_dirty(ifile);
2004
2005		clear_bit(NILFS_I_QUEUED, &ii->i_state);
2006		set_bit(NILFS_I_BUSY, &ii->i_state);
2007		list_move_tail(&ii->i_dirty, &sci->sc_dirty_files);
2008	}
2009	spin_unlock(&nilfs->ns_inode_lock);
2010
2011	return 0;
2012}
2013
2014static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
2015					     struct the_nilfs *nilfs)
2016{
 
2017	struct nilfs_inode_info *ii, *n;
2018	int during_mount = !(sci->sc_super->s_flags & SB_ACTIVE);
2019	int defer_iput = false;
2020
2021	spin_lock(&nilfs->ns_inode_lock);
2022	list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
2023		if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
2024		    test_bit(NILFS_I_DIRTY, &ii->i_state))
2025			continue;
2026
2027		clear_bit(NILFS_I_BUSY, &ii->i_state);
2028		brelse(ii->i_bh);
2029		ii->i_bh = NULL;
2030		list_del_init(&ii->i_dirty);
2031		if (!ii->vfs_inode.i_nlink || during_mount) {
2032			/*
2033			 * Defer calling iput() to avoid deadlocks if
2034			 * i_nlink == 0 or mount is not yet finished.
2035			 */
2036			list_add_tail(&ii->i_dirty, &sci->sc_iput_queue);
2037			defer_iput = true;
2038		} else {
2039			spin_unlock(&nilfs->ns_inode_lock);
2040			iput(&ii->vfs_inode);
2041			spin_lock(&nilfs->ns_inode_lock);
2042		}
2043	}
2044	spin_unlock(&nilfs->ns_inode_lock);
2045
2046	if (defer_iput)
2047		schedule_work(&sci->sc_iput_work);
2048}
2049
2050/*
2051 * Main procedure of segment constructor
2052 */
2053static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
2054{
2055	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2056	int err;
2057
2058	if (sb_rdonly(sci->sc_super))
2059		return -EROFS;
2060
2061	nilfs_sc_cstage_set(sci, NILFS_ST_INIT);
2062	sci->sc_cno = nilfs->ns_cno;
2063
2064	err = nilfs_segctor_collect_dirty_files(sci, nilfs);
2065	if (unlikely(err))
2066		goto out;
2067
2068	if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
2069		set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
2070
2071	if (nilfs_segctor_clean(sci))
2072		goto out;
2073
2074	do {
2075		sci->sc_stage.flags &= ~NILFS_CF_HISTORY_MASK;
2076
2077		err = nilfs_segctor_begin_construction(sci, nilfs);
2078		if (unlikely(err))
2079			goto out;
2080
2081		/* Update time stamp */
2082		sci->sc_seg_ctime = ktime_get_real_seconds();
2083
2084		err = nilfs_segctor_collect(sci, nilfs, mode);
2085		if (unlikely(err))
2086			goto failed;
2087
2088		/* Avoid empty segment */
2089		if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE &&
2090		    nilfs_segbuf_empty(sci->sc_curseg)) {
2091			nilfs_segctor_abort_construction(sci, nilfs, 1);
2092			goto out;
2093		}
2094
2095		err = nilfs_segctor_assign(sci, mode);
2096		if (unlikely(err))
2097			goto failed;
2098
2099		if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2100			nilfs_segctor_fill_in_file_bmap(sci);
2101
2102		if (mode == SC_LSEG_SR &&
2103		    nilfs_sc_cstage_get(sci) >= NILFS_ST_CPFILE) {
2104			err = nilfs_segctor_fill_in_checkpoint(sci);
2105			if (unlikely(err))
2106				goto failed_to_write;
2107
2108			nilfs_segctor_fill_in_super_root(sci, nilfs);
2109		}
2110		nilfs_segctor_update_segusage(sci, nilfs->ns_sufile);
2111
2112		/* Write partial segments */
2113		nilfs_segctor_prepare_write(sci);
2114
2115		nilfs_add_checksums_on_logs(&sci->sc_segbufs,
2116					    nilfs->ns_crc_seed);
2117
2118		err = nilfs_segctor_write(sci, nilfs);
2119		if (unlikely(err))
2120			goto failed_to_write;
2121
2122		if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE ||
2123		    nilfs->ns_blocksize_bits != PAGE_SHIFT) {
2124			/*
2125			 * At this point, we avoid double buffering
2126			 * for blocksize < pagesize because page dirty
2127			 * flag is turned off during write and dirty
2128			 * buffers are not properly collected for
2129			 * pages crossing over segments.
2130			 */
2131			err = nilfs_segctor_wait(sci);
2132			if (err)
2133				goto failed_to_write;
2134		}
2135	} while (nilfs_sc_cstage_get(sci) != NILFS_ST_DONE);
2136
2137 out:
2138	nilfs_segctor_drop_written_files(sci, nilfs);
2139	return err;
2140
2141 failed_to_write:
2142	if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2143		nilfs_redirty_inodes(&sci->sc_dirty_files);
2144
2145 failed:
2146	if (nilfs_doing_gc())
2147		nilfs_redirty_inodes(&sci->sc_gc_inodes);
2148	nilfs_segctor_abort_construction(sci, nilfs, err);
2149	goto out;
2150}
2151
2152/**
2153 * nilfs_segctor_start_timer - set timer of background write
2154 * @sci: nilfs_sc_info
2155 *
2156 * If the timer has already been set, it ignores the new request.
2157 * This function MUST be called within a section locking the segment
2158 * semaphore.
2159 */
2160static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
2161{
2162	spin_lock(&sci->sc_state_lock);
2163	if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
2164		sci->sc_timer.expires = jiffies + sci->sc_interval;
2165		add_timer(&sci->sc_timer);
2166		sci->sc_state |= NILFS_SEGCTOR_COMMIT;
2167	}
2168	spin_unlock(&sci->sc_state_lock);
2169}
2170
2171static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
2172{
2173	spin_lock(&sci->sc_state_lock);
2174	if (!(sci->sc_flush_request & BIT(bn))) {
2175		unsigned long prev_req = sci->sc_flush_request;
2176
2177		sci->sc_flush_request |= BIT(bn);
2178		if (!prev_req)
2179			wake_up(&sci->sc_wait_daemon);
2180	}
2181	spin_unlock(&sci->sc_state_lock);
2182}
2183
2184/**
2185 * nilfs_flush_segment - trigger a segment construction for resource control
2186 * @sb: super block
2187 * @ino: inode number of the file to be flushed out.
2188 */
2189void nilfs_flush_segment(struct super_block *sb, ino_t ino)
2190{
2191	struct the_nilfs *nilfs = sb->s_fs_info;
2192	struct nilfs_sc_info *sci = nilfs->ns_writer;
2193
2194	if (!sci || nilfs_doing_construction())
2195		return;
2196	nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
2197					/* assign bit 0 to data files */
2198}
2199
2200struct nilfs_segctor_wait_request {
2201	wait_queue_entry_t	wq;
2202	__u32		seq;
2203	int		err;
2204	atomic_t	done;
2205};
2206
2207static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
2208{
2209	struct nilfs_segctor_wait_request wait_req;
2210	int err = 0;
2211
2212	spin_lock(&sci->sc_state_lock);
2213	init_wait(&wait_req.wq);
2214	wait_req.err = 0;
2215	atomic_set(&wait_req.done, 0);
2216	wait_req.seq = ++sci->sc_seq_request;
2217	spin_unlock(&sci->sc_state_lock);
2218
2219	init_waitqueue_entry(&wait_req.wq, current);
2220	add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
2221	set_current_state(TASK_INTERRUPTIBLE);
2222	wake_up(&sci->sc_wait_daemon);
2223
2224	for (;;) {
2225		if (atomic_read(&wait_req.done)) {
2226			err = wait_req.err;
2227			break;
2228		}
2229		if (!signal_pending(current)) {
2230			schedule();
2231			continue;
2232		}
2233		err = -ERESTARTSYS;
2234		break;
2235	}
2236	finish_wait(&sci->sc_wait_request, &wait_req.wq);
2237	return err;
2238}
2239
2240static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
2241{
2242	struct nilfs_segctor_wait_request *wrq, *n;
2243	unsigned long flags;
2244
2245	spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
2246	list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.head, wq.entry) {
 
2247		if (!atomic_read(&wrq->done) &&
2248		    nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
2249			wrq->err = err;
2250			atomic_set(&wrq->done, 1);
2251		}
2252		if (atomic_read(&wrq->done)) {
2253			wrq->wq.func(&wrq->wq,
2254				     TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
2255				     0, NULL);
2256		}
2257	}
2258	spin_unlock_irqrestore(&sci->sc_wait_request.lock, flags);
2259}
2260
2261/**
2262 * nilfs_construct_segment - construct a logical segment
2263 * @sb: super block
2264 *
2265 * Return Value: On success, 0 is returned. On errors, one of the following
2266 * negative error code is returned.
2267 *
2268 * %-EROFS - Read only filesystem.
2269 *
2270 * %-EIO - I/O error
2271 *
2272 * %-ENOSPC - No space left on device (only in a panic state).
2273 *
2274 * %-ERESTARTSYS - Interrupted.
2275 *
2276 * %-ENOMEM - Insufficient memory available.
2277 */
2278int nilfs_construct_segment(struct super_block *sb)
2279{
2280	struct the_nilfs *nilfs = sb->s_fs_info;
2281	struct nilfs_sc_info *sci = nilfs->ns_writer;
2282	struct nilfs_transaction_info *ti;
 
2283
2284	if (sb_rdonly(sb) || unlikely(!sci))
2285		return -EROFS;
2286
2287	/* A call inside transactions causes a deadlock. */
2288	BUG_ON((ti = current->journal_info) && ti->ti_magic == NILFS_TI_MAGIC);
2289
2290	return nilfs_segctor_sync(sci);
 
2291}
2292
2293/**
2294 * nilfs_construct_dsync_segment - construct a data-only logical segment
2295 * @sb: super block
2296 * @inode: inode whose data blocks should be written out
2297 * @start: start byte offset
2298 * @end: end byte offset (inclusive)
2299 *
2300 * Return Value: On success, 0 is returned. On errors, one of the following
2301 * negative error code is returned.
2302 *
2303 * %-EROFS - Read only filesystem.
2304 *
2305 * %-EIO - I/O error
2306 *
2307 * %-ENOSPC - No space left on device (only in a panic state).
2308 *
2309 * %-ERESTARTSYS - Interrupted.
2310 *
2311 * %-ENOMEM - Insufficient memory available.
2312 */
2313int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
2314				  loff_t start, loff_t end)
2315{
2316	struct the_nilfs *nilfs = sb->s_fs_info;
2317	struct nilfs_sc_info *sci = nilfs->ns_writer;
2318	struct nilfs_inode_info *ii;
2319	struct nilfs_transaction_info ti;
2320	int err = 0;
2321
2322	if (sb_rdonly(sb) || unlikely(!sci))
2323		return -EROFS;
2324
2325	nilfs_transaction_lock(sb, &ti, 0);
2326
2327	ii = NILFS_I(inode);
2328	if (test_bit(NILFS_I_INODE_SYNC, &ii->i_state) ||
2329	    nilfs_test_opt(nilfs, STRICT_ORDER) ||
2330	    test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2331	    nilfs_discontinued(nilfs)) {
2332		nilfs_transaction_unlock(sb);
2333		err = nilfs_segctor_sync(sci);
2334		return err;
2335	}
2336
2337	spin_lock(&nilfs->ns_inode_lock);
2338	if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
2339	    !test_bit(NILFS_I_BUSY, &ii->i_state)) {
2340		spin_unlock(&nilfs->ns_inode_lock);
2341		nilfs_transaction_unlock(sb);
2342		return 0;
2343	}
2344	spin_unlock(&nilfs->ns_inode_lock);
2345	sci->sc_dsync_inode = ii;
2346	sci->sc_dsync_start = start;
2347	sci->sc_dsync_end = end;
2348
2349	err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC);
2350	if (!err)
2351		nilfs->ns_flushed_device = 0;
2352
2353	nilfs_transaction_unlock(sb);
2354	return err;
2355}
2356
2357#define FLUSH_FILE_BIT	(0x1) /* data file only */
2358#define FLUSH_DAT_BIT	BIT(NILFS_DAT_INO) /* DAT only */
2359
2360/**
2361 * nilfs_segctor_accept - record accepted sequence count of log-write requests
2362 * @sci: segment constructor object
2363 */
2364static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
2365{
2366	spin_lock(&sci->sc_state_lock);
2367	sci->sc_seq_accepted = sci->sc_seq_request;
2368	spin_unlock(&sci->sc_state_lock);
2369	del_timer_sync(&sci->sc_timer);
2370}
2371
2372/**
2373 * nilfs_segctor_notify - notify the result of request to caller threads
2374 * @sci: segment constructor object
2375 * @mode: mode of log forming
2376 * @err: error code to be notified
2377 */
2378static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
2379{
2380	/* Clear requests (even when the construction failed) */
2381	spin_lock(&sci->sc_state_lock);
2382
2383	if (mode == SC_LSEG_SR) {
2384		sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
2385		sci->sc_seq_done = sci->sc_seq_accepted;
2386		nilfs_segctor_wakeup(sci, err);
2387		sci->sc_flush_request = 0;
2388	} else {
2389		if (mode == SC_FLUSH_FILE)
2390			sci->sc_flush_request &= ~FLUSH_FILE_BIT;
2391		else if (mode == SC_FLUSH_DAT)
2392			sci->sc_flush_request &= ~FLUSH_DAT_BIT;
2393
2394		/* re-enable timer if checkpoint creation was not done */
2395		if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2396		    time_before(jiffies, sci->sc_timer.expires))
2397			add_timer(&sci->sc_timer);
2398	}
2399	spin_unlock(&sci->sc_state_lock);
2400}
2401
2402/**
2403 * nilfs_segctor_construct - form logs and write them to disk
2404 * @sci: segment constructor object
2405 * @mode: mode of log forming
2406 */
2407static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
2408{
2409	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2410	struct nilfs_super_block **sbp;
2411	int err = 0;
2412
2413	nilfs_segctor_accept(sci);
2414
2415	if (nilfs_discontinued(nilfs))
2416		mode = SC_LSEG_SR;
2417	if (!nilfs_segctor_confirm(sci))
2418		err = nilfs_segctor_do_construct(sci, mode);
2419
2420	if (likely(!err)) {
2421		if (mode != SC_FLUSH_DAT)
2422			atomic_set(&nilfs->ns_ndirtyblks, 0);
2423		if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
2424		    nilfs_discontinued(nilfs)) {
2425			down_write(&nilfs->ns_sem);
2426			err = -EIO;
2427			sbp = nilfs_prepare_super(sci->sc_super,
2428						  nilfs_sb_will_flip(nilfs));
2429			if (likely(sbp)) {
2430				nilfs_set_log_cursor(sbp[0], nilfs);
2431				err = nilfs_commit_super(sci->sc_super,
2432							 NILFS_SB_COMMIT);
2433			}
2434			up_write(&nilfs->ns_sem);
2435		}
2436	}
2437
2438	nilfs_segctor_notify(sci, mode, err);
2439	return err;
2440}
2441
2442static void nilfs_construction_timeout(struct timer_list *t)
2443{
2444	struct nilfs_sc_info *sci = from_timer(sci, t, sc_timer);
2445
2446	wake_up_process(sci->sc_timer_task);
2447}
2448
2449static void
2450nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
2451{
2452	struct nilfs_inode_info *ii, *n;
2453
2454	list_for_each_entry_safe(ii, n, head, i_dirty) {
2455		if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
2456			continue;
2457		list_del_init(&ii->i_dirty);
2458		truncate_inode_pages(&ii->vfs_inode.i_data, 0);
2459		nilfs_btnode_cache_clear(ii->i_assoc_inode->i_mapping);
2460		iput(&ii->vfs_inode);
2461	}
2462}
2463
2464int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
2465			 void **kbufs)
2466{
2467	struct the_nilfs *nilfs = sb->s_fs_info;
2468	struct nilfs_sc_info *sci = nilfs->ns_writer;
2469	struct nilfs_transaction_info ti;
2470	int err;
2471
2472	if (unlikely(!sci))
2473		return -EROFS;
2474
2475	nilfs_transaction_lock(sb, &ti, 1);
2476
2477	err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
2478	if (unlikely(err))
2479		goto out_unlock;
2480
2481	err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
2482	if (unlikely(err)) {
2483		nilfs_mdt_restore_from_shadow_map(nilfs->ns_dat);
2484		goto out_unlock;
2485	}
2486
2487	sci->sc_freesegs = kbufs[4];
2488	sci->sc_nfreesegs = argv[4].v_nmembs;
2489	list_splice_tail_init(&nilfs->ns_gc_inodes, &sci->sc_gc_inodes);
2490
2491	for (;;) {
2492		err = nilfs_segctor_construct(sci, SC_LSEG_SR);
2493		nilfs_remove_written_gcinodes(nilfs, &sci->sc_gc_inodes);
2494
2495		if (likely(!err))
2496			break;
2497
2498		nilfs_warn(sb, "error %d cleaning segments", err);
 
2499		set_current_state(TASK_INTERRUPTIBLE);
2500		schedule_timeout(sci->sc_interval);
2501	}
2502	if (nilfs_test_opt(nilfs, DISCARD)) {
2503		int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
2504						 sci->sc_nfreesegs);
2505		if (ret) {
2506			nilfs_warn(sb,
2507				   "error %d on discard request, turning discards off for the device",
2508				   ret);
2509			nilfs_clear_opt(nilfs, DISCARD);
2510		}
2511	}
2512
2513 out_unlock:
2514	sci->sc_freesegs = NULL;
2515	sci->sc_nfreesegs = 0;
2516	nilfs_mdt_clear_shadow_map(nilfs->ns_dat);
2517	nilfs_transaction_unlock(sb);
2518	return err;
2519}
2520
2521static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
2522{
2523	struct nilfs_transaction_info ti;
2524
2525	nilfs_transaction_lock(sci->sc_super, &ti, 0);
2526	nilfs_segctor_construct(sci, mode);
2527
2528	/*
2529	 * Unclosed segment should be retried.  We do this using sc_timer.
2530	 * Timeout of sc_timer will invoke complete construction which leads
2531	 * to close the current logical segment.
2532	 */
2533	if (test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags))
2534		nilfs_segctor_start_timer(sci);
2535
2536	nilfs_transaction_unlock(sci->sc_super);
2537}
2538
2539static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
2540{
2541	int mode = 0;
 
2542
2543	spin_lock(&sci->sc_state_lock);
2544	mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
2545		SC_FLUSH_DAT : SC_FLUSH_FILE;
2546	spin_unlock(&sci->sc_state_lock);
2547
2548	if (mode) {
2549		nilfs_segctor_do_construct(sci, mode);
2550
2551		spin_lock(&sci->sc_state_lock);
2552		sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
2553			~FLUSH_FILE_BIT : ~FLUSH_DAT_BIT;
2554		spin_unlock(&sci->sc_state_lock);
2555	}
2556	clear_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
2557}
2558
2559static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
2560{
2561	if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2562	    time_before(jiffies, sci->sc_lseg_stime + sci->sc_mjcp_freq)) {
2563		if (!(sci->sc_flush_request & ~FLUSH_FILE_BIT))
2564			return SC_FLUSH_FILE;
2565		else if (!(sci->sc_flush_request & ~FLUSH_DAT_BIT))
2566			return SC_FLUSH_DAT;
2567	}
2568	return SC_LSEG_SR;
2569}
2570
2571/**
2572 * nilfs_segctor_thread - main loop of the segment constructor thread.
2573 * @arg: pointer to a struct nilfs_sc_info.
2574 *
2575 * nilfs_segctor_thread() initializes a timer and serves as a daemon
2576 * to execute segment constructions.
2577 */
2578static int nilfs_segctor_thread(void *arg)
2579{
2580	struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
2581	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2582	int timeout = 0;
2583
2584	sci->sc_timer_task = current;
 
2585
2586	/* start sync. */
2587	sci->sc_task = current;
2588	wake_up(&sci->sc_wait_task); /* for nilfs_segctor_start_thread() */
2589	nilfs_info(sci->sc_super,
2590		   "segctord starting. Construction interval = %lu seconds, CP frequency < %lu seconds",
2591		   sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
 
2592
2593	set_freezable();
2594	spin_lock(&sci->sc_state_lock);
2595 loop:
2596	for (;;) {
2597		int mode;
2598
2599		if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2600			goto end_thread;
2601
2602		if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2603			mode = SC_LSEG_SR;
2604		else if (sci->sc_flush_request)
2605			mode = nilfs_segctor_flush_mode(sci);
2606		else
2607			break;
 
 
2608
2609		spin_unlock(&sci->sc_state_lock);
2610		nilfs_segctor_thread_construct(sci, mode);
2611		spin_lock(&sci->sc_state_lock);
2612		timeout = 0;
2613	}
2614
2615
2616	if (freezing(current)) {
2617		spin_unlock(&sci->sc_state_lock);
2618		try_to_freeze();
2619		spin_lock(&sci->sc_state_lock);
2620	} else {
2621		DEFINE_WAIT(wait);
2622		int should_sleep = 1;
2623
2624		prepare_to_wait(&sci->sc_wait_daemon, &wait,
2625				TASK_INTERRUPTIBLE);
2626
2627		if (sci->sc_seq_request != sci->sc_seq_done)
2628			should_sleep = 0;
2629		else if (sci->sc_flush_request)
2630			should_sleep = 0;
2631		else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2632			should_sleep = time_before(jiffies,
2633					sci->sc_timer.expires);
2634
2635		if (should_sleep) {
2636			spin_unlock(&sci->sc_state_lock);
2637			schedule();
2638			spin_lock(&sci->sc_state_lock);
2639		}
2640		finish_wait(&sci->sc_wait_daemon, &wait);
2641		timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2642			   time_after_eq(jiffies, sci->sc_timer.expires));
2643
2644		if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2645			set_nilfs_discontinued(nilfs);
2646	}
2647	goto loop;
2648
2649 end_thread:
 
 
2650	/* end sync. */
2651	sci->sc_task = NULL;
2652	wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
2653	spin_unlock(&sci->sc_state_lock);
2654	return 0;
2655}
2656
2657static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2658{
2659	struct task_struct *t;
2660
2661	t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2662	if (IS_ERR(t)) {
2663		int err = PTR_ERR(t);
2664
2665		nilfs_err(sci->sc_super, "error %d creating segctord thread",
2666			  err);
2667		return err;
2668	}
2669	wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2670	return 0;
2671}
2672
2673static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2674	__acquires(&sci->sc_state_lock)
2675	__releases(&sci->sc_state_lock)
2676{
2677	sci->sc_state |= NILFS_SEGCTOR_QUIT;
2678
2679	while (sci->sc_task) {
2680		wake_up(&sci->sc_wait_daemon);
2681		spin_unlock(&sci->sc_state_lock);
2682		wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2683		spin_lock(&sci->sc_state_lock);
2684	}
2685}
2686
2687/*
2688 * Setup & clean-up functions
2689 */
2690static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
2691					       struct nilfs_root *root)
2692{
2693	struct the_nilfs *nilfs = sb->s_fs_info;
2694	struct nilfs_sc_info *sci;
2695
2696	sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2697	if (!sci)
2698		return NULL;
2699
2700	sci->sc_super = sb;
2701
2702	nilfs_get_root(root);
2703	sci->sc_root = root;
2704
2705	init_waitqueue_head(&sci->sc_wait_request);
2706	init_waitqueue_head(&sci->sc_wait_daemon);
2707	init_waitqueue_head(&sci->sc_wait_task);
2708	spin_lock_init(&sci->sc_state_lock);
2709	INIT_LIST_HEAD(&sci->sc_dirty_files);
2710	INIT_LIST_HEAD(&sci->sc_segbufs);
2711	INIT_LIST_HEAD(&sci->sc_write_logs);
2712	INIT_LIST_HEAD(&sci->sc_gc_inodes);
2713	INIT_LIST_HEAD(&sci->sc_iput_queue);
2714	INIT_WORK(&sci->sc_iput_work, nilfs_iput_work_func);
2715	timer_setup(&sci->sc_timer, nilfs_construction_timeout, 0);
2716
2717	sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2718	sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2719	sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2720
2721	if (nilfs->ns_interval)
2722		sci->sc_interval = HZ * nilfs->ns_interval;
2723	if (nilfs->ns_watermark)
2724		sci->sc_watermark = nilfs->ns_watermark;
2725	return sci;
2726}
2727
2728static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2729{
2730	int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2731
2732	/*
2733	 * The segctord thread was stopped and its timer was removed.
2734	 * But some tasks remain.
2735	 */
2736	do {
2737		struct nilfs_transaction_info ti;
2738
2739		nilfs_transaction_lock(sci->sc_super, &ti, 0);
2740		ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2741		nilfs_transaction_unlock(sci->sc_super);
2742
2743		flush_work(&sci->sc_iput_work);
2744
2745	} while (ret && ret != -EROFS && retrycount-- > 0);
2746}
2747
2748/**
2749 * nilfs_segctor_destroy - destroy the segment constructor.
2750 * @sci: nilfs_sc_info
2751 *
2752 * nilfs_segctor_destroy() kills the segctord thread and frees
2753 * the nilfs_sc_info struct.
2754 * Caller must hold the segment semaphore.
2755 */
2756static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2757{
2758	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2759	int flag;
2760
2761	up_write(&nilfs->ns_segctor_sem);
2762
2763	spin_lock(&sci->sc_state_lock);
2764	nilfs_segctor_kill_thread(sci);
2765	flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2766		|| sci->sc_seq_request != sci->sc_seq_done);
2767	spin_unlock(&sci->sc_state_lock);
2768
2769	if (flush_work(&sci->sc_iput_work))
2770		flag = true;
2771
2772	if (flag || !nilfs_segctor_confirm(sci))
2773		nilfs_segctor_write_out(sci);
2774
2775	if (!list_empty(&sci->sc_dirty_files)) {
2776		nilfs_warn(sci->sc_super,
2777			   "disposed unprocessed dirty file(s) when stopping log writer");
2778		nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2779	}
2780
2781	if (!list_empty(&sci->sc_iput_queue)) {
2782		nilfs_warn(sci->sc_super,
2783			   "disposed unprocessed inode(s) in iput queue when stopping log writer");
2784		nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 1);
2785	}
2786
2787	WARN_ON(!list_empty(&sci->sc_segbufs));
2788	WARN_ON(!list_empty(&sci->sc_write_logs));
2789
2790	nilfs_put_root(sci->sc_root);
2791
2792	down_write(&nilfs->ns_segctor_sem);
2793
2794	timer_shutdown_sync(&sci->sc_timer);
2795	kfree(sci);
2796}
2797
2798/**
2799 * nilfs_attach_log_writer - attach log writer
2800 * @sb: super block instance
2801 * @root: root object of the current filesystem tree
2802 *
2803 * This allocates a log writer object, initializes it, and starts the
2804 * log writer.
2805 *
2806 * Return Value: On success, 0 is returned. On error, one of the following
2807 * negative error code is returned.
2808 *
2809 * %-ENOMEM - Insufficient memory available.
2810 */
2811int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
2812{
2813	struct the_nilfs *nilfs = sb->s_fs_info;
2814	int err;
2815
2816	if (nilfs->ns_writer) {
2817		/*
2818		 * This happens if the filesystem is made read-only by
2819		 * __nilfs_error or nilfs_remount and then remounted
2820		 * read/write.  In these cases, reuse the existing
2821		 * writer.
2822		 */
2823		return 0;
2824	}
2825
2826	nilfs->ns_writer = nilfs_segctor_new(sb, root);
2827	if (!nilfs->ns_writer)
2828		return -ENOMEM;
2829
2830	inode_attach_wb(nilfs->ns_bdev->bd_inode, NULL);
2831
2832	err = nilfs_segctor_start_thread(nilfs->ns_writer);
2833	if (unlikely(err))
2834		nilfs_detach_log_writer(sb);
2835
 
2836	return err;
2837}
2838
2839/**
2840 * nilfs_detach_log_writer - destroy log writer
2841 * @sb: super block instance
2842 *
2843 * This kills log writer daemon, frees the log writer object, and
2844 * destroys list of dirty files.
2845 */
2846void nilfs_detach_log_writer(struct super_block *sb)
2847{
2848	struct the_nilfs *nilfs = sb->s_fs_info;
2849	LIST_HEAD(garbage_list);
2850
2851	down_write(&nilfs->ns_segctor_sem);
2852	if (nilfs->ns_writer) {
2853		nilfs_segctor_destroy(nilfs->ns_writer);
2854		nilfs->ns_writer = NULL;
2855	}
2856	set_nilfs_purging(nilfs);
2857
2858	/* Force to free the list of dirty files */
2859	spin_lock(&nilfs->ns_inode_lock);
2860	if (!list_empty(&nilfs->ns_dirty_files)) {
2861		list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2862		nilfs_warn(sb,
2863			   "disposed unprocessed dirty file(s) when detaching log writer");
2864	}
2865	spin_unlock(&nilfs->ns_inode_lock);
2866	up_write(&nilfs->ns_segctor_sem);
2867
2868	nilfs_dispose_list(nilfs, &garbage_list, 1);
2869	clear_nilfs_purging(nilfs);
2870}
v3.15
 
   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) || buffer_async_write(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						!buffer_async_write(bh)) {
 704					get_bh(bh);
 705					list_add_tail(&bh->b_assoc_buffers,
 706						      listp);
 707				}
 708				bh = bh->b_this_page;
 709			} while (bh != head);
 710		}
 711		pagevec_release(&pvec);
 712		cond_resched();
 713	}
 714}
 715
 716static void nilfs_dispose_list(struct the_nilfs *nilfs,
 717			       struct list_head *head, int force)
 718{
 719	struct nilfs_inode_info *ii, *n;
 720	struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
 721	unsigned nv = 0;
 722
 723	while (!list_empty(head)) {
 724		spin_lock(&nilfs->ns_inode_lock);
 725		list_for_each_entry_safe(ii, n, head, i_dirty) {
 726			list_del_init(&ii->i_dirty);
 727			if (force) {
 728				if (unlikely(ii->i_bh)) {
 729					brelse(ii->i_bh);
 730					ii->i_bh = NULL;
 731				}
 732			} else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
 733				set_bit(NILFS_I_QUEUED, &ii->i_state);
 734				list_add_tail(&ii->i_dirty,
 735					      &nilfs->ns_dirty_files);
 736				continue;
 737			}
 738			ivec[nv++] = ii;
 739			if (nv == SC_N_INODEVEC)
 740				break;
 741		}
 742		spin_unlock(&nilfs->ns_inode_lock);
 743
 744		for (pii = ivec; nv > 0; pii++, nv--)
 745			iput(&(*pii)->vfs_inode);
 746	}
 747}
 748
 
 
 
 
 
 
 
 
 
 749static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
 750				     struct nilfs_root *root)
 751{
 752	int ret = 0;
 753
 754	if (nilfs_mdt_fetch_dirty(root->ifile))
 755		ret++;
 756	if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
 757		ret++;
 758	if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
 759		ret++;
 760	if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
 761		ret++;
 762	return ret;
 763}
 764
 765static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 766{
 767	return list_empty(&sci->sc_dirty_files) &&
 768		!test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
 769		sci->sc_nfreesegs == 0 &&
 770		(!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
 771}
 772
 773static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 774{
 775	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 776	int ret = 0;
 777
 778	if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
 779		set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
 780
 781	spin_lock(&nilfs->ns_inode_lock);
 782	if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
 783		ret++;
 784
 785	spin_unlock(&nilfs->ns_inode_lock);
 786	return ret;
 787}
 788
 789static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 790{
 791	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 792
 793	nilfs_mdt_clear_dirty(sci->sc_root->ifile);
 794	nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
 795	nilfs_mdt_clear_dirty(nilfs->ns_sufile);
 796	nilfs_mdt_clear_dirty(nilfs->ns_dat);
 797}
 798
 799static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
 800{
 801	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 802	struct buffer_head *bh_cp;
 803	struct nilfs_checkpoint *raw_cp;
 804	int err;
 805
 806	/* XXX: this interface will be changed */
 807	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 1,
 808					  &raw_cp, &bh_cp);
 809	if (likely(!err)) {
 810		/* The following code is duplicated with cpfile.  But, it is
 811		   needed to collect the checkpoint even if it was not newly
 812		   created */
 
 
 813		mark_buffer_dirty(bh_cp);
 814		nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
 815		nilfs_cpfile_put_checkpoint(
 816			nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 817	} else
 818		WARN_ON(err == -EINVAL || err == -ENOENT);
 819
 
 
 820	return err;
 821}
 822
 823static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
 824{
 825	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 826	struct buffer_head *bh_cp;
 827	struct nilfs_checkpoint *raw_cp;
 828	int err;
 829
 830	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
 831					  &raw_cp, &bh_cp);
 832	if (unlikely(err)) {
 833		WARN_ON(err == -EINVAL || err == -ENOENT);
 
 
 
 
 834		goto failed_ibh;
 835	}
 836	raw_cp->cp_snapshot_list.ssl_next = 0;
 837	raw_cp->cp_snapshot_list.ssl_prev = 0;
 838	raw_cp->cp_inodes_count =
 839		cpu_to_le64(atomic64_read(&sci->sc_root->inodes_count));
 840	raw_cp->cp_blocks_count =
 841		cpu_to_le64(atomic64_read(&sci->sc_root->blocks_count));
 842	raw_cp->cp_nblk_inc =
 843		cpu_to_le64(sci->sc_nblk_inc + sci->sc_nblk_this_inc);
 844	raw_cp->cp_create = cpu_to_le64(sci->sc_seg_ctime);
 845	raw_cp->cp_cno = cpu_to_le64(nilfs->ns_cno);
 846
 847	if (test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
 848		nilfs_checkpoint_clear_minor(raw_cp);
 849	else
 850		nilfs_checkpoint_set_minor(raw_cp);
 851
 852	nilfs_write_inode_common(sci->sc_root->ifile,
 853				 &raw_cp->cp_ifile_inode, 1);
 854	nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
 855	return 0;
 856
 857 failed_ibh:
 858	return err;
 859}
 860
 861static void nilfs_fill_in_file_bmap(struct inode *ifile,
 862				    struct nilfs_inode_info *ii)
 863
 864{
 865	struct buffer_head *ibh;
 866	struct nilfs_inode *raw_inode;
 867
 868	if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
 869		ibh = ii->i_bh;
 870		BUG_ON(!ibh);
 871		raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
 872						  ibh);
 873		nilfs_bmap_write(ii->i_bmap, raw_inode);
 874		nilfs_ifile_unmap_inode(ifile, ii->vfs_inode.i_ino, ibh);
 875	}
 876}
 877
 878static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
 879{
 880	struct nilfs_inode_info *ii;
 881
 882	list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
 883		nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
 884		set_bit(NILFS_I_COLLECTED, &ii->i_state);
 885	}
 886}
 887
 888static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 889					     struct the_nilfs *nilfs)
 890{
 891	struct buffer_head *bh_sr;
 892	struct nilfs_super_root *raw_sr;
 893	unsigned isz, srsz;
 894
 895	bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
 
 
 896	raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 897	isz = nilfs->ns_inode_size;
 898	srsz = NILFS_SR_BYTES(isz);
 899
 
 900	raw_sr->sr_bytes = cpu_to_le16(srsz);
 901	raw_sr->sr_nongc_ctime
 902		= cpu_to_le64(nilfs_doing_gc() ?
 903			      nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
 904	raw_sr->sr_flags = 0;
 905
 906	nilfs_write_inode_common(nilfs->ns_dat, (void *)raw_sr +
 907				 NILFS_SR_DAT_OFFSET(isz), 1);
 908	nilfs_write_inode_common(nilfs->ns_cpfile, (void *)raw_sr +
 909				 NILFS_SR_CPFILE_OFFSET(isz), 1);
 910	nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
 911				 NILFS_SR_SUFILE_OFFSET(isz), 1);
 912	memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
 
 
 913}
 914
 915static void nilfs_redirty_inodes(struct list_head *head)
 916{
 917	struct nilfs_inode_info *ii;
 918
 919	list_for_each_entry(ii, head, i_dirty) {
 920		if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
 921			clear_bit(NILFS_I_COLLECTED, &ii->i_state);
 922	}
 923}
 924
 925static void nilfs_drop_collected_inodes(struct list_head *head)
 926{
 927	struct nilfs_inode_info *ii;
 928
 929	list_for_each_entry(ii, head, i_dirty) {
 930		if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
 931			continue;
 932
 933		clear_bit(NILFS_I_INODE_DIRTY, &ii->i_state);
 934		set_bit(NILFS_I_UPDATED, &ii->i_state);
 935	}
 936}
 937
 938static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
 939				       struct inode *inode,
 940				       struct list_head *listp,
 941				       int (*collect)(struct nilfs_sc_info *,
 942						      struct buffer_head *,
 943						      struct inode *))
 944{
 945	struct buffer_head *bh, *n;
 946	int err = 0;
 947
 948	if (collect) {
 949		list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
 950			list_del_init(&bh->b_assoc_buffers);
 951			err = collect(sci, bh, inode);
 952			brelse(bh);
 953			if (unlikely(err))
 954				goto dispose_buffers;
 955		}
 956		return 0;
 957	}
 958
 959 dispose_buffers:
 960	while (!list_empty(listp)) {
 961		bh = list_first_entry(listp, struct buffer_head,
 962				      b_assoc_buffers);
 963		list_del_init(&bh->b_assoc_buffers);
 964		brelse(bh);
 965	}
 966	return err;
 967}
 968
 969static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
 970{
 971	/* Remaining number of blocks within segment buffer */
 972	return sci->sc_segbuf_nblocks -
 973		(sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
 974}
 975
 976static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
 977				   struct inode *inode,
 978				   struct nilfs_sc_operations *sc_ops)
 979{
 980	LIST_HEAD(data_buffers);
 981	LIST_HEAD(node_buffers);
 982	int err;
 983
 984	if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
 985		size_t n, rest = nilfs_segctor_buffer_rest(sci);
 986
 987		n = nilfs_lookup_dirty_data_buffers(
 988			inode, &data_buffers, rest + 1, 0, LLONG_MAX);
 989		if (n > rest) {
 990			err = nilfs_segctor_apply_buffers(
 991				sci, inode, &data_buffers,
 992				sc_ops->collect_data);
 993			BUG_ON(!err); /* always receive -E2BIG or true error */
 994			goto break_or_fail;
 995		}
 996	}
 997	nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
 998
 999	if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1000		err = nilfs_segctor_apply_buffers(
1001			sci, inode, &data_buffers, sc_ops->collect_data);
1002		if (unlikely(err)) {
1003			/* dispose node list */
1004			nilfs_segctor_apply_buffers(
1005				sci, inode, &node_buffers, NULL);
1006			goto break_or_fail;
1007		}
1008		sci->sc_stage.flags |= NILFS_CF_NODE;
1009	}
1010	/* Collect node */
1011	err = nilfs_segctor_apply_buffers(
1012		sci, inode, &node_buffers, sc_ops->collect_node);
1013	if (unlikely(err))
1014		goto break_or_fail;
1015
1016	nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1017	err = nilfs_segctor_apply_buffers(
1018		sci, inode, &node_buffers, sc_ops->collect_bmap);
1019	if (unlikely(err))
1020		goto break_or_fail;
1021
1022	nilfs_segctor_end_finfo(sci, inode);
1023	sci->sc_stage.flags &= ~NILFS_CF_NODE;
1024
1025 break_or_fail:
1026	return err;
1027}
1028
1029static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1030					 struct inode *inode)
1031{
1032	LIST_HEAD(data_buffers);
1033	size_t n, rest = nilfs_segctor_buffer_rest(sci);
1034	int err;
1035
1036	n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1037					    sci->sc_dsync_start,
1038					    sci->sc_dsync_end);
1039
1040	err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1041					  nilfs_collect_file_data);
1042	if (!err) {
1043		nilfs_segctor_end_finfo(sci, inode);
1044		BUG_ON(n > rest);
1045		/* always receive -E2BIG or true error if n > rest */
1046	}
1047	return err;
1048}
1049
1050static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1051{
1052	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1053	struct list_head *head;
1054	struct nilfs_inode_info *ii;
1055	size_t ndone;
1056	int err = 0;
1057
1058	switch (sci->sc_stage.scnt) {
1059	case NILFS_ST_INIT:
1060		/* Pre-processes */
1061		sci->sc_stage.flags = 0;
1062
1063		if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1064			sci->sc_nblk_inc = 0;
1065			sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1066			if (mode == SC_LSEG_DSYNC) {
1067				sci->sc_stage.scnt = NILFS_ST_DSYNC;
1068				goto dsync_mode;
1069			}
1070		}
1071
1072		sci->sc_stage.dirty_file_ptr = NULL;
1073		sci->sc_stage.gc_inode_ptr = NULL;
1074		if (mode == SC_FLUSH_DAT) {
1075			sci->sc_stage.scnt = NILFS_ST_DAT;
1076			goto dat_stage;
1077		}
1078		sci->sc_stage.scnt++;  /* Fall through */
 
1079	case NILFS_ST_GC:
1080		if (nilfs_doing_gc()) {
1081			head = &sci->sc_gc_inodes;
1082			ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1083						head, i_dirty);
1084			list_for_each_entry_continue(ii, head, i_dirty) {
1085				err = nilfs_segctor_scan_file(
1086					sci, &ii->vfs_inode,
1087					&nilfs_sc_file_ops);
1088				if (unlikely(err)) {
1089					sci->sc_stage.gc_inode_ptr = list_entry(
1090						ii->i_dirty.prev,
1091						struct nilfs_inode_info,
1092						i_dirty);
1093					goto break_or_fail;
1094				}
1095				set_bit(NILFS_I_COLLECTED, &ii->i_state);
1096			}
1097			sci->sc_stage.gc_inode_ptr = NULL;
1098		}
1099		sci->sc_stage.scnt++;  /* Fall through */
 
1100	case NILFS_ST_FILE:
1101		head = &sci->sc_dirty_files;
1102		ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1103					i_dirty);
1104		list_for_each_entry_continue(ii, head, i_dirty) {
1105			clear_bit(NILFS_I_DIRTY, &ii->i_state);
1106
1107			err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1108						      &nilfs_sc_file_ops);
1109			if (unlikely(err)) {
1110				sci->sc_stage.dirty_file_ptr =
1111					list_entry(ii->i_dirty.prev,
1112						   struct nilfs_inode_info,
1113						   i_dirty);
1114				goto break_or_fail;
1115			}
1116			/* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1117			/* XXX: required ? */
1118		}
1119		sci->sc_stage.dirty_file_ptr = NULL;
1120		if (mode == SC_FLUSH_FILE) {
1121			sci->sc_stage.scnt = NILFS_ST_DONE;
1122			return 0;
1123		}
1124		sci->sc_stage.scnt++;
1125		sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1126		/* Fall through */
1127	case NILFS_ST_IFILE:
1128		err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1129					      &nilfs_sc_file_ops);
1130		if (unlikely(err))
1131			break;
1132		sci->sc_stage.scnt++;
1133		/* Creating a checkpoint */
1134		err = nilfs_segctor_create_checkpoint(sci);
1135		if (unlikely(err))
1136			break;
1137		/* Fall through */
1138	case NILFS_ST_CPFILE:
1139		err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1140					      &nilfs_sc_file_ops);
1141		if (unlikely(err))
1142			break;
1143		sci->sc_stage.scnt++;  /* Fall through */
 
1144	case NILFS_ST_SUFILE:
1145		err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1146					 sci->sc_nfreesegs, &ndone);
1147		if (unlikely(err)) {
1148			nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1149						  sci->sc_freesegs, ndone,
1150						  NULL);
1151			break;
1152		}
1153		sci->sc_stage.flags |= NILFS_CF_SUFREED;
1154
1155		err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1156					      &nilfs_sc_file_ops);
1157		if (unlikely(err))
1158			break;
1159		sci->sc_stage.scnt++;  /* Fall through */
 
1160	case NILFS_ST_DAT:
1161 dat_stage:
1162		err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1163					      &nilfs_sc_dat_ops);
1164		if (unlikely(err))
1165			break;
1166		if (mode == SC_FLUSH_DAT) {
1167			sci->sc_stage.scnt = NILFS_ST_DONE;
1168			return 0;
1169		}
1170		sci->sc_stage.scnt++;  /* Fall through */
 
1171	case NILFS_ST_SR:
1172		if (mode == SC_LSEG_SR) {
1173			/* Appending a super root */
1174			err = nilfs_segctor_add_super_root(sci);
1175			if (unlikely(err))
1176				break;
1177		}
1178		/* End of a logical segment */
1179		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1180		sci->sc_stage.scnt = NILFS_ST_DONE;
1181		return 0;
1182	case NILFS_ST_DSYNC:
1183 dsync_mode:
1184		sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1185		ii = sci->sc_dsync_inode;
1186		if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1187			break;
1188
1189		err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1190		if (unlikely(err))
1191			break;
1192		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1193		sci->sc_stage.scnt = NILFS_ST_DONE;
1194		return 0;
1195	case NILFS_ST_DONE:
1196		return 0;
1197	default:
1198		BUG();
1199	}
1200
1201 break_or_fail:
1202	return err;
1203}
1204
1205/**
1206 * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1207 * @sci: nilfs_sc_info
1208 * @nilfs: nilfs object
1209 */
1210static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1211					    struct the_nilfs *nilfs)
1212{
1213	struct nilfs_segment_buffer *segbuf, *prev;
1214	__u64 nextnum;
1215	int err, alloc = 0;
1216
1217	segbuf = nilfs_segbuf_new(sci->sc_super);
1218	if (unlikely(!segbuf))
1219		return -ENOMEM;
1220
1221	if (list_empty(&sci->sc_write_logs)) {
1222		nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1223				 nilfs->ns_pseg_offset, nilfs);
1224		if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1225			nilfs_shift_to_next_segment(nilfs);
1226			nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1227		}
1228
1229		segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1230		nextnum = nilfs->ns_nextnum;
1231
1232		if (nilfs->ns_segnum == nilfs->ns_nextnum)
1233			/* Start from the head of a new full segment */
1234			alloc++;
1235	} else {
1236		/* Continue logs */
1237		prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1238		nilfs_segbuf_map_cont(segbuf, prev);
1239		segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1240		nextnum = prev->sb_nextnum;
1241
1242		if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1243			nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1244			segbuf->sb_sum.seg_seq++;
1245			alloc++;
1246		}
1247	}
1248
1249	err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1250	if (err)
1251		goto failed;
1252
1253	if (alloc) {
1254		err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1255		if (err)
1256			goto failed;
1257	}
1258	nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1259
1260	BUG_ON(!list_empty(&sci->sc_segbufs));
1261	list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1262	sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1263	return 0;
1264
1265 failed:
1266	nilfs_segbuf_free(segbuf);
1267	return err;
1268}
1269
1270static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1271					 struct the_nilfs *nilfs, int nadd)
1272{
1273	struct nilfs_segment_buffer *segbuf, *prev;
1274	struct inode *sufile = nilfs->ns_sufile;
1275	__u64 nextnextnum;
1276	LIST_HEAD(list);
1277	int err, ret, i;
1278
1279	prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1280	/*
1281	 * Since the segment specified with nextnum might be allocated during
1282	 * the previous construction, the buffer including its segusage may
1283	 * not be dirty.  The following call ensures that the buffer is dirty
1284	 * and will pin the buffer on memory until the sufile is written.
1285	 */
1286	err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1287	if (unlikely(err))
1288		return err;
1289
1290	for (i = 0; i < nadd; i++) {
1291		/* extend segment info */
1292		err = -ENOMEM;
1293		segbuf = nilfs_segbuf_new(sci->sc_super);
1294		if (unlikely(!segbuf))
1295			goto failed;
1296
1297		/* map this buffer to region of segment on-disk */
1298		nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1299		sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1300
1301		/* allocate the next next full segment */
1302		err = nilfs_sufile_alloc(sufile, &nextnextnum);
1303		if (unlikely(err))
1304			goto failed_segbuf;
1305
1306		segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1307		nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1308
1309		list_add_tail(&segbuf->sb_list, &list);
1310		prev = segbuf;
1311	}
1312	list_splice_tail(&list, &sci->sc_segbufs);
1313	return 0;
1314
1315 failed_segbuf:
1316	nilfs_segbuf_free(segbuf);
1317 failed:
1318	list_for_each_entry(segbuf, &list, sb_list) {
1319		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1320		WARN_ON(ret); /* never fails */
1321	}
1322	nilfs_destroy_logs(&list);
1323	return err;
1324}
1325
1326static void nilfs_free_incomplete_logs(struct list_head *logs,
1327				       struct the_nilfs *nilfs)
1328{
1329	struct nilfs_segment_buffer *segbuf, *prev;
1330	struct inode *sufile = nilfs->ns_sufile;
1331	int ret;
1332
1333	segbuf = NILFS_FIRST_SEGBUF(logs);
1334	if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1335		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1336		WARN_ON(ret); /* never fails */
1337	}
1338	if (atomic_read(&segbuf->sb_err)) {
1339		/* Case 1: The first segment failed */
1340		if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1341			/* Case 1a:  Partial segment appended into an existing
1342			   segment */
 
 
1343			nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1344						segbuf->sb_fseg_end);
1345		else /* Case 1b:  New full segment */
1346			set_nilfs_discontinued(nilfs);
1347	}
1348
1349	prev = segbuf;
1350	list_for_each_entry_continue(segbuf, logs, sb_list) {
1351		if (prev->sb_nextnum != segbuf->sb_nextnum) {
1352			ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1353			WARN_ON(ret); /* never fails */
1354		}
1355		if (atomic_read(&segbuf->sb_err) &&
1356		    segbuf->sb_segnum != nilfs->ns_nextnum)
1357			/* Case 2: extended segment (!= next) failed */
1358			nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1359		prev = segbuf;
1360	}
1361}
1362
1363static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1364					  struct inode *sufile)
1365{
1366	struct nilfs_segment_buffer *segbuf;
1367	unsigned long live_blocks;
1368	int ret;
1369
1370	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1371		live_blocks = segbuf->sb_sum.nblocks +
1372			(segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1373		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1374						     live_blocks,
1375						     sci->sc_seg_ctime);
1376		WARN_ON(ret); /* always succeed because the segusage is dirty */
1377	}
1378}
1379
1380static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1381{
1382	struct nilfs_segment_buffer *segbuf;
1383	int ret;
1384
1385	segbuf = NILFS_FIRST_SEGBUF(logs);
1386	ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1387					     segbuf->sb_pseg_start -
1388					     segbuf->sb_fseg_start, 0);
1389	WARN_ON(ret); /* always succeed because the segusage is dirty */
1390
1391	list_for_each_entry_continue(segbuf, logs, sb_list) {
1392		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1393						     0, 0);
1394		WARN_ON(ret); /* always succeed */
1395	}
1396}
1397
1398static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1399					    struct nilfs_segment_buffer *last,
1400					    struct inode *sufile)
1401{
1402	struct nilfs_segment_buffer *segbuf = last;
1403	int ret;
1404
1405	list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1406		sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1407		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1408		WARN_ON(ret);
1409	}
1410	nilfs_truncate_logs(&sci->sc_segbufs, last);
1411}
1412
1413
1414static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1415				 struct the_nilfs *nilfs, int mode)
1416{
1417	struct nilfs_cstage prev_stage = sci->sc_stage;
1418	int err, nadd = 1;
1419
1420	/* Collection retry loop */
1421	for (;;) {
1422		sci->sc_nblk_this_inc = 0;
1423		sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1424
1425		err = nilfs_segctor_reset_segment_buffer(sci);
1426		if (unlikely(err))
1427			goto failed;
1428
1429		err = nilfs_segctor_collect_blocks(sci, mode);
1430		sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1431		if (!err)
1432			break;
1433
1434		if (unlikely(err != -E2BIG))
1435			goto failed;
1436
1437		/* The current segment is filled up */
1438		if (mode != SC_LSEG_SR || sci->sc_stage.scnt < NILFS_ST_CPFILE)
 
1439			break;
1440
1441		nilfs_clear_logs(&sci->sc_segbufs);
1442
1443		if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1444			err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1445							sci->sc_freesegs,
1446							sci->sc_nfreesegs,
1447							NULL);
1448			WARN_ON(err); /* do not happen */
1449			sci->sc_stage.flags &= ~NILFS_CF_SUFREED;
1450		}
1451
1452		err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1453		if (unlikely(err))
1454			return err;
1455
1456		nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1457		sci->sc_stage = prev_stage;
1458	}
 
1459	nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1460	return 0;
1461
1462 failed:
1463	return err;
1464}
1465
1466static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1467				      struct buffer_head *new_bh)
1468{
1469	BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1470
1471	list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1472	/* The caller must release old_bh */
1473}
1474
1475static int
1476nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1477				     struct nilfs_segment_buffer *segbuf,
1478				     int mode)
1479{
1480	struct inode *inode = NULL;
1481	sector_t blocknr;
1482	unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1483	unsigned long nblocks = 0, ndatablk = 0;
1484	struct nilfs_sc_operations *sc_op = NULL;
1485	struct nilfs_segsum_pointer ssp;
1486	struct nilfs_finfo *finfo = NULL;
1487	union nilfs_binfo binfo;
1488	struct buffer_head *bh, *bh_org;
1489	ino_t ino = 0;
1490	int err = 0;
1491
1492	if (!nfinfo)
1493		goto out;
1494
1495	blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1496	ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1497	ssp.offset = sizeof(struct nilfs_segment_summary);
1498
1499	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1500		if (bh == segbuf->sb_super_root)
1501			break;
1502		if (!finfo) {
1503			finfo =	nilfs_segctor_map_segsum_entry(
1504				sci, &ssp, sizeof(*finfo));
1505			ino = le64_to_cpu(finfo->fi_ino);
1506			nblocks = le32_to_cpu(finfo->fi_nblocks);
1507			ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1508
1509			inode = bh->b_page->mapping->host;
1510
1511			if (mode == SC_LSEG_DSYNC)
1512				sc_op = &nilfs_sc_dsync_ops;
1513			else if (ino == NILFS_DAT_INO)
1514				sc_op = &nilfs_sc_dat_ops;
1515			else /* file blocks */
1516				sc_op = &nilfs_sc_file_ops;
1517		}
1518		bh_org = bh;
1519		get_bh(bh_org);
1520		err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1521					&binfo);
1522		if (bh != bh_org)
1523			nilfs_list_replace_buffer(bh_org, bh);
1524		brelse(bh_org);
1525		if (unlikely(err))
1526			goto failed_bmap;
1527
1528		if (ndatablk > 0)
1529			sc_op->write_data_binfo(sci, &ssp, &binfo);
1530		else
1531			sc_op->write_node_binfo(sci, &ssp, &binfo);
1532
1533		blocknr++;
1534		if (--nblocks == 0) {
1535			finfo = NULL;
1536			if (--nfinfo == 0)
1537				break;
1538		} else if (ndatablk > 0)
1539			ndatablk--;
1540	}
1541 out:
1542	return 0;
1543
1544 failed_bmap:
1545	return err;
1546}
1547
1548static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1549{
1550	struct nilfs_segment_buffer *segbuf;
1551	int err;
1552
1553	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1554		err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1555		if (unlikely(err))
1556			return err;
1557		nilfs_segbuf_fill_in_segsum(segbuf);
1558	}
1559	return 0;
1560}
1561
1562static void nilfs_begin_page_io(struct page *page)
1563{
1564	if (!page || PageWriteback(page))
1565		/* For split b-tree node pages, this function may be called
1566		   twice.  We ignore the 2nd or later calls by this check. */
 
 
1567		return;
1568
1569	lock_page(page);
1570	clear_page_dirty_for_io(page);
1571	set_page_writeback(page);
1572	unlock_page(page);
1573}
1574
1575static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci)
1576{
1577	struct nilfs_segment_buffer *segbuf;
1578	struct page *bd_page = NULL, *fs_page = NULL;
1579
1580	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1581		struct buffer_head *bh;
1582
1583		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1584				    b_assoc_buffers) {
1585			set_buffer_async_write(bh);
1586			if (bh->b_page != bd_page) {
1587				if (bd_page) {
1588					lock_page(bd_page);
1589					clear_page_dirty_for_io(bd_page);
1590					set_page_writeback(bd_page);
1591					unlock_page(bd_page);
1592				}
1593				bd_page = bh->b_page;
1594			}
1595		}
1596
1597		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1598				    b_assoc_buffers) {
1599			set_buffer_async_write(bh);
1600			if (bh == segbuf->sb_super_root) {
1601				if (bh->b_page != bd_page) {
1602					lock_page(bd_page);
1603					clear_page_dirty_for_io(bd_page);
1604					set_page_writeback(bd_page);
1605					unlock_page(bd_page);
1606					bd_page = bh->b_page;
1607				}
1608				break;
1609			}
1610			if (bh->b_page != fs_page) {
1611				nilfs_begin_page_io(fs_page);
1612				fs_page = bh->b_page;
 
1613			}
1614		}
1615	}
1616	if (bd_page) {
1617		lock_page(bd_page);
1618		clear_page_dirty_for_io(bd_page);
1619		set_page_writeback(bd_page);
1620		unlock_page(bd_page);
1621	}
1622	nilfs_begin_page_io(fs_page);
1623}
1624
1625static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1626			       struct the_nilfs *nilfs)
1627{
1628	int ret;
1629
1630	ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1631	list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1632	return ret;
1633}
1634
1635static void nilfs_end_page_io(struct page *page, int err)
1636{
1637	if (!page)
1638		return;
1639
1640	if (buffer_nilfs_node(page_buffers(page)) && !PageWriteback(page)) {
 
1641		/*
1642		 * For b-tree node pages, this function may be called twice
1643		 * or more because they might be split in a segment.
1644		 */
1645		if (PageDirty(page)) {
1646			/*
1647			 * For pages holding split b-tree node buffers, dirty
1648			 * flag on the buffers may be cleared discretely.
1649			 * In that case, the page is once redirtied for
1650			 * remaining buffers, and it must be cancelled if
1651			 * all the buffers get cleaned later.
1652			 */
1653			lock_page(page);
1654			if (nilfs_page_buffers_clean(page))
1655				__nilfs_clear_page_dirty(page);
1656			unlock_page(page);
1657		}
1658		return;
1659	}
1660
1661	if (!err) {
1662		if (!nilfs_page_buffers_clean(page))
1663			__set_page_dirty_nobuffers(page);
1664		ClearPageError(page);
1665	} else {
1666		__set_page_dirty_nobuffers(page);
1667		SetPageError(page);
1668	}
1669
1670	end_page_writeback(page);
1671}
1672
1673static void nilfs_abort_logs(struct list_head *logs, int err)
1674{
1675	struct nilfs_segment_buffer *segbuf;
1676	struct page *bd_page = NULL, *fs_page = NULL;
1677	struct buffer_head *bh;
1678
1679	if (list_empty(logs))
1680		return;
1681
1682	list_for_each_entry(segbuf, logs, sb_list) {
1683		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1684				    b_assoc_buffers) {
1685			clear_buffer_async_write(bh);
1686			if (bh->b_page != bd_page) {
1687				if (bd_page)
1688					end_page_writeback(bd_page);
1689				bd_page = bh->b_page;
1690			}
1691		}
1692
1693		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1694				    b_assoc_buffers) {
1695			clear_buffer_async_write(bh);
1696			if (bh == segbuf->sb_super_root) {
1697				if (bh->b_page != bd_page) {
1698					end_page_writeback(bd_page);
1699					bd_page = bh->b_page;
 
1700				}
1701				break;
1702			}
1703			if (bh->b_page != fs_page) {
1704				nilfs_end_page_io(fs_page, err);
1705				fs_page = bh->b_page;
 
1706			}
1707		}
1708	}
1709	if (bd_page)
1710		end_page_writeback(bd_page);
1711
1712	nilfs_end_page_io(fs_page, err);
1713}
1714
1715static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
1716					     struct the_nilfs *nilfs, int err)
1717{
1718	LIST_HEAD(logs);
1719	int ret;
1720
1721	list_splice_tail_init(&sci->sc_write_logs, &logs);
1722	ret = nilfs_wait_on_logs(&logs);
1723	nilfs_abort_logs(&logs, ret ? : err);
1724
1725	list_splice_tail_init(&sci->sc_segbufs, &logs);
1726	nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
1727	nilfs_free_incomplete_logs(&logs, nilfs);
1728
1729	if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1730		ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1731						sci->sc_freesegs,
1732						sci->sc_nfreesegs,
1733						NULL);
1734		WARN_ON(ret); /* do not happen */
1735	}
1736
1737	nilfs_destroy_logs(&logs);
1738}
1739
1740static void nilfs_set_next_segment(struct the_nilfs *nilfs,
1741				   struct nilfs_segment_buffer *segbuf)
1742{
1743	nilfs->ns_segnum = segbuf->sb_segnum;
1744	nilfs->ns_nextnum = segbuf->sb_nextnum;
1745	nilfs->ns_pseg_offset = segbuf->sb_pseg_start - segbuf->sb_fseg_start
1746		+ segbuf->sb_sum.nblocks;
1747	nilfs->ns_seg_seq = segbuf->sb_sum.seg_seq;
1748	nilfs->ns_ctime = segbuf->sb_sum.ctime;
1749}
1750
1751static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
1752{
1753	struct nilfs_segment_buffer *segbuf;
1754	struct page *bd_page = NULL, *fs_page = NULL;
1755	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1756	int update_sr = false;
1757
1758	list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
1759		struct buffer_head *bh;
1760
1761		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1762				    b_assoc_buffers) {
1763			set_buffer_uptodate(bh);
1764			clear_buffer_dirty(bh);
1765			clear_buffer_async_write(bh);
1766			if (bh->b_page != bd_page) {
1767				if (bd_page)
1768					end_page_writeback(bd_page);
1769				bd_page = bh->b_page;
1770			}
1771		}
1772		/*
1773		 * We assume that the buffers which belong to the same page
1774		 * continue over the buffer list.
1775		 * Under this assumption, the last BHs of pages is
1776		 * identifiable by the discontinuity of bh->b_page
1777		 * (page != fs_page).
1778		 *
1779		 * For B-tree node blocks, however, this assumption is not
1780		 * guaranteed.  The cleanup code of B-tree node pages needs
1781		 * special care.
1782		 */
1783		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1784				    b_assoc_buffers) {
1785			set_buffer_uptodate(bh);
1786			clear_buffer_dirty(bh);
1787			clear_buffer_async_write(bh);
1788			clear_buffer_delay(bh);
1789			clear_buffer_nilfs_volatile(bh);
1790			clear_buffer_nilfs_redirected(bh);
1791			if (bh == segbuf->sb_super_root) {
1792				if (bh->b_page != bd_page) {
1793					end_page_writeback(bd_page);
1794					bd_page = bh->b_page;
 
 
1795				}
1796				update_sr = true;
1797				break;
1798			}
1799			if (bh->b_page != fs_page) {
1800				nilfs_end_page_io(fs_page, 0);
1801				fs_page = bh->b_page;
 
1802			}
1803		}
1804
1805		if (!nilfs_segbuf_simplex(segbuf)) {
1806			if (segbuf->sb_sum.flags & NILFS_SS_LOGBGN) {
1807				set_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1808				sci->sc_lseg_stime = jiffies;
1809			}
1810			if (segbuf->sb_sum.flags & NILFS_SS_LOGEND)
1811				clear_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1812		}
1813	}
1814	/*
1815	 * Since pages may continue over multiple segment buffers,
1816	 * end of the last page must be checked outside of the loop.
1817	 */
1818	if (bd_page)
1819		end_page_writeback(bd_page);
1820
1821	nilfs_end_page_io(fs_page, 0);
1822
1823	nilfs_drop_collected_inodes(&sci->sc_dirty_files);
1824
1825	if (nilfs_doing_gc())
1826		nilfs_drop_collected_inodes(&sci->sc_gc_inodes);
1827	else
1828		nilfs->ns_nongc_ctime = sci->sc_seg_ctime;
1829
1830	sci->sc_nblk_inc += sci->sc_nblk_this_inc;
1831
1832	segbuf = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1833	nilfs_set_next_segment(nilfs, segbuf);
1834
1835	if (update_sr) {
 
1836		nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
1837				       segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
1838
1839		clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
1840		clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1841		set_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1842		nilfs_segctor_clear_metadata_dirty(sci);
1843	} else
1844		clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1845}
1846
1847static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
1848{
1849	int ret;
1850
1851	ret = nilfs_wait_on_logs(&sci->sc_write_logs);
1852	if (!ret) {
1853		nilfs_segctor_complete_write(sci);
1854		nilfs_destroy_logs(&sci->sc_write_logs);
1855	}
1856	return ret;
1857}
1858
1859static int nilfs_segctor_collect_dirty_files(struct nilfs_sc_info *sci,
1860					     struct the_nilfs *nilfs)
1861{
1862	struct nilfs_inode_info *ii, *n;
1863	struct inode *ifile = sci->sc_root->ifile;
1864
1865	spin_lock(&nilfs->ns_inode_lock);
1866 retry:
1867	list_for_each_entry_safe(ii, n, &nilfs->ns_dirty_files, i_dirty) {
1868		if (!ii->i_bh) {
1869			struct buffer_head *ibh;
1870			int err;
1871
1872			spin_unlock(&nilfs->ns_inode_lock);
1873			err = nilfs_ifile_get_inode_block(
1874				ifile, ii->vfs_inode.i_ino, &ibh);
1875			if (unlikely(err)) {
1876				nilfs_warning(sci->sc_super, __func__,
1877					      "failed to get inode block.\n");
 
1878				return err;
1879			}
1880			mark_buffer_dirty(ibh);
1881			nilfs_mdt_mark_dirty(ifile);
1882			spin_lock(&nilfs->ns_inode_lock);
1883			if (likely(!ii->i_bh))
1884				ii->i_bh = ibh;
1885			else
1886				brelse(ibh);
1887			goto retry;
1888		}
1889
 
 
 
 
1890		clear_bit(NILFS_I_QUEUED, &ii->i_state);
1891		set_bit(NILFS_I_BUSY, &ii->i_state);
1892		list_move_tail(&ii->i_dirty, &sci->sc_dirty_files);
1893	}
1894	spin_unlock(&nilfs->ns_inode_lock);
1895
1896	return 0;
1897}
1898
1899static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
1900					     struct the_nilfs *nilfs)
1901{
1902	struct nilfs_transaction_info *ti = current->journal_info;
1903	struct nilfs_inode_info *ii, *n;
 
 
1904
1905	spin_lock(&nilfs->ns_inode_lock);
1906	list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
1907		if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
1908		    test_bit(NILFS_I_DIRTY, &ii->i_state))
1909			continue;
1910
1911		clear_bit(NILFS_I_BUSY, &ii->i_state);
1912		brelse(ii->i_bh);
1913		ii->i_bh = NULL;
1914		list_move_tail(&ii->i_dirty, &ti->ti_garbage);
 
 
 
 
 
 
 
 
 
 
 
 
1915	}
1916	spin_unlock(&nilfs->ns_inode_lock);
 
 
 
1917}
1918
1919/*
1920 * Main procedure of segment constructor
1921 */
1922static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
1923{
1924	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1925	int err;
1926
1927	sci->sc_stage.scnt = NILFS_ST_INIT;
 
 
 
1928	sci->sc_cno = nilfs->ns_cno;
1929
1930	err = nilfs_segctor_collect_dirty_files(sci, nilfs);
1931	if (unlikely(err))
1932		goto out;
1933
1934	if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
1935		set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1936
1937	if (nilfs_segctor_clean(sci))
1938		goto out;
1939
1940	do {
1941		sci->sc_stage.flags &= ~NILFS_CF_HISTORY_MASK;
1942
1943		err = nilfs_segctor_begin_construction(sci, nilfs);
1944		if (unlikely(err))
1945			goto out;
1946
1947		/* Update time stamp */
1948		sci->sc_seg_ctime = get_seconds();
1949
1950		err = nilfs_segctor_collect(sci, nilfs, mode);
1951		if (unlikely(err))
1952			goto failed;
1953
1954		/* Avoid empty segment */
1955		if (sci->sc_stage.scnt == NILFS_ST_DONE &&
1956		    nilfs_segbuf_empty(sci->sc_curseg)) {
1957			nilfs_segctor_abort_construction(sci, nilfs, 1);
1958			goto out;
1959		}
1960
1961		err = nilfs_segctor_assign(sci, mode);
1962		if (unlikely(err))
1963			goto failed;
1964
1965		if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
1966			nilfs_segctor_fill_in_file_bmap(sci);
1967
1968		if (mode == SC_LSEG_SR &&
1969		    sci->sc_stage.scnt >= NILFS_ST_CPFILE) {
1970			err = nilfs_segctor_fill_in_checkpoint(sci);
1971			if (unlikely(err))
1972				goto failed_to_write;
1973
1974			nilfs_segctor_fill_in_super_root(sci, nilfs);
1975		}
1976		nilfs_segctor_update_segusage(sci, nilfs->ns_sufile);
1977
1978		/* Write partial segments */
1979		nilfs_segctor_prepare_write(sci);
1980
1981		nilfs_add_checksums_on_logs(&sci->sc_segbufs,
1982					    nilfs->ns_crc_seed);
1983
1984		err = nilfs_segctor_write(sci, nilfs);
1985		if (unlikely(err))
1986			goto failed_to_write;
1987
1988		if (sci->sc_stage.scnt == NILFS_ST_DONE ||
1989		    nilfs->ns_blocksize_bits != PAGE_CACHE_SHIFT) {
1990			/*
1991			 * At this point, we avoid double buffering
1992			 * for blocksize < pagesize because page dirty
1993			 * flag is turned off during write and dirty
1994			 * buffers are not properly collected for
1995			 * pages crossing over segments.
1996			 */
1997			err = nilfs_segctor_wait(sci);
1998			if (err)
1999				goto failed_to_write;
2000		}
2001	} while (sci->sc_stage.scnt != NILFS_ST_DONE);
2002
2003 out:
2004	nilfs_segctor_drop_written_files(sci, nilfs);
2005	return err;
2006
2007 failed_to_write:
2008	if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2009		nilfs_redirty_inodes(&sci->sc_dirty_files);
2010
2011 failed:
2012	if (nilfs_doing_gc())
2013		nilfs_redirty_inodes(&sci->sc_gc_inodes);
2014	nilfs_segctor_abort_construction(sci, nilfs, err);
2015	goto out;
2016}
2017
2018/**
2019 * nilfs_segctor_start_timer - set timer of background write
2020 * @sci: nilfs_sc_info
2021 *
2022 * If the timer has already been set, it ignores the new request.
2023 * This function MUST be called within a section locking the segment
2024 * semaphore.
2025 */
2026static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
2027{
2028	spin_lock(&sci->sc_state_lock);
2029	if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
2030		sci->sc_timer.expires = jiffies + sci->sc_interval;
2031		add_timer(&sci->sc_timer);
2032		sci->sc_state |= NILFS_SEGCTOR_COMMIT;
2033	}
2034	spin_unlock(&sci->sc_state_lock);
2035}
2036
2037static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
2038{
2039	spin_lock(&sci->sc_state_lock);
2040	if (!(sci->sc_flush_request & (1 << bn))) {
2041		unsigned long prev_req = sci->sc_flush_request;
2042
2043		sci->sc_flush_request |= (1 << bn);
2044		if (!prev_req)
2045			wake_up(&sci->sc_wait_daemon);
2046	}
2047	spin_unlock(&sci->sc_state_lock);
2048}
2049
2050/**
2051 * nilfs_flush_segment - trigger a segment construction for resource control
2052 * @sb: super block
2053 * @ino: inode number of the file to be flushed out.
2054 */
2055void nilfs_flush_segment(struct super_block *sb, ino_t ino)
2056{
2057	struct the_nilfs *nilfs = sb->s_fs_info;
2058	struct nilfs_sc_info *sci = nilfs->ns_writer;
2059
2060	if (!sci || nilfs_doing_construction())
2061		return;
2062	nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
2063					/* assign bit 0 to data files */
2064}
2065
2066struct nilfs_segctor_wait_request {
2067	wait_queue_t	wq;
2068	__u32		seq;
2069	int		err;
2070	atomic_t	done;
2071};
2072
2073static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
2074{
2075	struct nilfs_segctor_wait_request wait_req;
2076	int err = 0;
2077
2078	spin_lock(&sci->sc_state_lock);
2079	init_wait(&wait_req.wq);
2080	wait_req.err = 0;
2081	atomic_set(&wait_req.done, 0);
2082	wait_req.seq = ++sci->sc_seq_request;
2083	spin_unlock(&sci->sc_state_lock);
2084
2085	init_waitqueue_entry(&wait_req.wq, current);
2086	add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
2087	set_current_state(TASK_INTERRUPTIBLE);
2088	wake_up(&sci->sc_wait_daemon);
2089
2090	for (;;) {
2091		if (atomic_read(&wait_req.done)) {
2092			err = wait_req.err;
2093			break;
2094		}
2095		if (!signal_pending(current)) {
2096			schedule();
2097			continue;
2098		}
2099		err = -ERESTARTSYS;
2100		break;
2101	}
2102	finish_wait(&sci->sc_wait_request, &wait_req.wq);
2103	return err;
2104}
2105
2106static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
2107{
2108	struct nilfs_segctor_wait_request *wrq, *n;
2109	unsigned long flags;
2110
2111	spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
2112	list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.task_list,
2113				 wq.task_list) {
2114		if (!atomic_read(&wrq->done) &&
2115		    nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
2116			wrq->err = err;
2117			atomic_set(&wrq->done, 1);
2118		}
2119		if (atomic_read(&wrq->done)) {
2120			wrq->wq.func(&wrq->wq,
2121				     TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
2122				     0, NULL);
2123		}
2124	}
2125	spin_unlock_irqrestore(&sci->sc_wait_request.lock, flags);
2126}
2127
2128/**
2129 * nilfs_construct_segment - construct a logical segment
2130 * @sb: super block
2131 *
2132 * Return Value: On success, 0 is retured. On errors, one of the following
2133 * negative error code is returned.
2134 *
2135 * %-EROFS - Read only filesystem.
2136 *
2137 * %-EIO - I/O error
2138 *
2139 * %-ENOSPC - No space left on device (only in a panic state).
2140 *
2141 * %-ERESTARTSYS - Interrupted.
2142 *
2143 * %-ENOMEM - Insufficient memory available.
2144 */
2145int nilfs_construct_segment(struct super_block *sb)
2146{
2147	struct the_nilfs *nilfs = sb->s_fs_info;
2148	struct nilfs_sc_info *sci = nilfs->ns_writer;
2149	struct nilfs_transaction_info *ti;
2150	int err;
2151
2152	if (!sci)
2153		return -EROFS;
2154
2155	/* A call inside transactions causes a deadlock. */
2156	BUG_ON((ti = current->journal_info) && ti->ti_magic == NILFS_TI_MAGIC);
2157
2158	err = nilfs_segctor_sync(sci);
2159	return err;
2160}
2161
2162/**
2163 * nilfs_construct_dsync_segment - construct a data-only logical segment
2164 * @sb: super block
2165 * @inode: inode whose data blocks should be written out
2166 * @start: start byte offset
2167 * @end: end byte offset (inclusive)
2168 *
2169 * Return Value: On success, 0 is retured. On errors, one of the following
2170 * negative error code is returned.
2171 *
2172 * %-EROFS - Read only filesystem.
2173 *
2174 * %-EIO - I/O error
2175 *
2176 * %-ENOSPC - No space left on device (only in a panic state).
2177 *
2178 * %-ERESTARTSYS - Interrupted.
2179 *
2180 * %-ENOMEM - Insufficient memory available.
2181 */
2182int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
2183				  loff_t start, loff_t end)
2184{
2185	struct the_nilfs *nilfs = sb->s_fs_info;
2186	struct nilfs_sc_info *sci = nilfs->ns_writer;
2187	struct nilfs_inode_info *ii;
2188	struct nilfs_transaction_info ti;
2189	int err = 0;
2190
2191	if (!sci)
2192		return -EROFS;
2193
2194	nilfs_transaction_lock(sb, &ti, 0);
2195
2196	ii = NILFS_I(inode);
2197	if (test_bit(NILFS_I_INODE_DIRTY, &ii->i_state) ||
2198	    nilfs_test_opt(nilfs, STRICT_ORDER) ||
2199	    test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2200	    nilfs_discontinued(nilfs)) {
2201		nilfs_transaction_unlock(sb);
2202		err = nilfs_segctor_sync(sci);
2203		return err;
2204	}
2205
2206	spin_lock(&nilfs->ns_inode_lock);
2207	if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
2208	    !test_bit(NILFS_I_BUSY, &ii->i_state)) {
2209		spin_unlock(&nilfs->ns_inode_lock);
2210		nilfs_transaction_unlock(sb);
2211		return 0;
2212	}
2213	spin_unlock(&nilfs->ns_inode_lock);
2214	sci->sc_dsync_inode = ii;
2215	sci->sc_dsync_start = start;
2216	sci->sc_dsync_end = end;
2217
2218	err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC);
 
 
2219
2220	nilfs_transaction_unlock(sb);
2221	return err;
2222}
2223
2224#define FLUSH_FILE_BIT	(0x1) /* data file only */
2225#define FLUSH_DAT_BIT	(1 << NILFS_DAT_INO) /* DAT only */
2226
2227/**
2228 * nilfs_segctor_accept - record accepted sequence count of log-write requests
2229 * @sci: segment constructor object
2230 */
2231static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
2232{
2233	spin_lock(&sci->sc_state_lock);
2234	sci->sc_seq_accepted = sci->sc_seq_request;
2235	spin_unlock(&sci->sc_state_lock);
2236	del_timer_sync(&sci->sc_timer);
2237}
2238
2239/**
2240 * nilfs_segctor_notify - notify the result of request to caller threads
2241 * @sci: segment constructor object
2242 * @mode: mode of log forming
2243 * @err: error code to be notified
2244 */
2245static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
2246{
2247	/* Clear requests (even when the construction failed) */
2248	spin_lock(&sci->sc_state_lock);
2249
2250	if (mode == SC_LSEG_SR) {
2251		sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
2252		sci->sc_seq_done = sci->sc_seq_accepted;
2253		nilfs_segctor_wakeup(sci, err);
2254		sci->sc_flush_request = 0;
2255	} else {
2256		if (mode == SC_FLUSH_FILE)
2257			sci->sc_flush_request &= ~FLUSH_FILE_BIT;
2258		else if (mode == SC_FLUSH_DAT)
2259			sci->sc_flush_request &= ~FLUSH_DAT_BIT;
2260
2261		/* re-enable timer if checkpoint creation was not done */
2262		if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2263		    time_before(jiffies, sci->sc_timer.expires))
2264			add_timer(&sci->sc_timer);
2265	}
2266	spin_unlock(&sci->sc_state_lock);
2267}
2268
2269/**
2270 * nilfs_segctor_construct - form logs and write them to disk
2271 * @sci: segment constructor object
2272 * @mode: mode of log forming
2273 */
2274static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
2275{
2276	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2277	struct nilfs_super_block **sbp;
2278	int err = 0;
2279
2280	nilfs_segctor_accept(sci);
2281
2282	if (nilfs_discontinued(nilfs))
2283		mode = SC_LSEG_SR;
2284	if (!nilfs_segctor_confirm(sci))
2285		err = nilfs_segctor_do_construct(sci, mode);
2286
2287	if (likely(!err)) {
2288		if (mode != SC_FLUSH_DAT)
2289			atomic_set(&nilfs->ns_ndirtyblks, 0);
2290		if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
2291		    nilfs_discontinued(nilfs)) {
2292			down_write(&nilfs->ns_sem);
2293			err = -EIO;
2294			sbp = nilfs_prepare_super(sci->sc_super,
2295						  nilfs_sb_will_flip(nilfs));
2296			if (likely(sbp)) {
2297				nilfs_set_log_cursor(sbp[0], nilfs);
2298				err = nilfs_commit_super(sci->sc_super,
2299							 NILFS_SB_COMMIT);
2300			}
2301			up_write(&nilfs->ns_sem);
2302		}
2303	}
2304
2305	nilfs_segctor_notify(sci, mode, err);
2306	return err;
2307}
2308
2309static void nilfs_construction_timeout(unsigned long data)
2310{
2311	struct task_struct *p = (struct task_struct *)data;
2312	wake_up_process(p);
 
2313}
2314
2315static void
2316nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
2317{
2318	struct nilfs_inode_info *ii, *n;
2319
2320	list_for_each_entry_safe(ii, n, head, i_dirty) {
2321		if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
2322			continue;
2323		list_del_init(&ii->i_dirty);
2324		truncate_inode_pages(&ii->vfs_inode.i_data, 0);
2325		nilfs_btnode_cache_clear(&ii->i_btnode_cache);
2326		iput(&ii->vfs_inode);
2327	}
2328}
2329
2330int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
2331			 void **kbufs)
2332{
2333	struct the_nilfs *nilfs = sb->s_fs_info;
2334	struct nilfs_sc_info *sci = nilfs->ns_writer;
2335	struct nilfs_transaction_info ti;
2336	int err;
2337
2338	if (unlikely(!sci))
2339		return -EROFS;
2340
2341	nilfs_transaction_lock(sb, &ti, 1);
2342
2343	err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
2344	if (unlikely(err))
2345		goto out_unlock;
2346
2347	err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
2348	if (unlikely(err)) {
2349		nilfs_mdt_restore_from_shadow_map(nilfs->ns_dat);
2350		goto out_unlock;
2351	}
2352
2353	sci->sc_freesegs = kbufs[4];
2354	sci->sc_nfreesegs = argv[4].v_nmembs;
2355	list_splice_tail_init(&nilfs->ns_gc_inodes, &sci->sc_gc_inodes);
2356
2357	for (;;) {
2358		err = nilfs_segctor_construct(sci, SC_LSEG_SR);
2359		nilfs_remove_written_gcinodes(nilfs, &sci->sc_gc_inodes);
2360
2361		if (likely(!err))
2362			break;
2363
2364		nilfs_warning(sb, __func__,
2365			      "segment construction failed. (err=%d)", err);
2366		set_current_state(TASK_INTERRUPTIBLE);
2367		schedule_timeout(sci->sc_interval);
2368	}
2369	if (nilfs_test_opt(nilfs, DISCARD)) {
2370		int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
2371						 sci->sc_nfreesegs);
2372		if (ret) {
2373			printk(KERN_WARNING
2374			       "NILFS warning: error %d on discard request, "
2375			       "turning discards off for the device\n", ret);
2376			nilfs_clear_opt(nilfs, DISCARD);
2377		}
2378	}
2379
2380 out_unlock:
2381	sci->sc_freesegs = NULL;
2382	sci->sc_nfreesegs = 0;
2383	nilfs_mdt_clear_shadow_map(nilfs->ns_dat);
2384	nilfs_transaction_unlock(sb);
2385	return err;
2386}
2387
2388static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
2389{
2390	struct nilfs_transaction_info ti;
2391
2392	nilfs_transaction_lock(sci->sc_super, &ti, 0);
2393	nilfs_segctor_construct(sci, mode);
2394
2395	/*
2396	 * Unclosed segment should be retried.  We do this using sc_timer.
2397	 * Timeout of sc_timer will invoke complete construction which leads
2398	 * to close the current logical segment.
2399	 */
2400	if (test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags))
2401		nilfs_segctor_start_timer(sci);
2402
2403	nilfs_transaction_unlock(sci->sc_super);
2404}
2405
2406static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
2407{
2408	int mode = 0;
2409	int err;
2410
2411	spin_lock(&sci->sc_state_lock);
2412	mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
2413		SC_FLUSH_DAT : SC_FLUSH_FILE;
2414	spin_unlock(&sci->sc_state_lock);
2415
2416	if (mode) {
2417		err = nilfs_segctor_do_construct(sci, mode);
2418
2419		spin_lock(&sci->sc_state_lock);
2420		sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
2421			~FLUSH_FILE_BIT : ~FLUSH_DAT_BIT;
2422		spin_unlock(&sci->sc_state_lock);
2423	}
2424	clear_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
2425}
2426
2427static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
2428{
2429	if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2430	    time_before(jiffies, sci->sc_lseg_stime + sci->sc_mjcp_freq)) {
2431		if (!(sci->sc_flush_request & ~FLUSH_FILE_BIT))
2432			return SC_FLUSH_FILE;
2433		else if (!(sci->sc_flush_request & ~FLUSH_DAT_BIT))
2434			return SC_FLUSH_DAT;
2435	}
2436	return SC_LSEG_SR;
2437}
2438
2439/**
2440 * nilfs_segctor_thread - main loop of the segment constructor thread.
2441 * @arg: pointer to a struct nilfs_sc_info.
2442 *
2443 * nilfs_segctor_thread() initializes a timer and serves as a daemon
2444 * to execute segment constructions.
2445 */
2446static int nilfs_segctor_thread(void *arg)
2447{
2448	struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
2449	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2450	int timeout = 0;
2451
2452	sci->sc_timer.data = (unsigned long)current;
2453	sci->sc_timer.function = nilfs_construction_timeout;
2454
2455	/* start sync. */
2456	sci->sc_task = current;
2457	wake_up(&sci->sc_wait_task); /* for nilfs_segctor_start_thread() */
2458	printk(KERN_INFO
2459	       "segctord starting. Construction interval = %lu seconds, "
2460	       "CP frequency < %lu seconds\n",
2461	       sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
2462
 
2463	spin_lock(&sci->sc_state_lock);
2464 loop:
2465	for (;;) {
2466		int mode;
2467
2468		if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2469			goto end_thread;
2470
2471		if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2472			mode = SC_LSEG_SR;
2473		else if (!sci->sc_flush_request)
 
 
2474			break;
2475		else
2476			mode = nilfs_segctor_flush_mode(sci);
2477
2478		spin_unlock(&sci->sc_state_lock);
2479		nilfs_segctor_thread_construct(sci, mode);
2480		spin_lock(&sci->sc_state_lock);
2481		timeout = 0;
2482	}
2483
2484
2485	if (freezing(current)) {
2486		spin_unlock(&sci->sc_state_lock);
2487		try_to_freeze();
2488		spin_lock(&sci->sc_state_lock);
2489	} else {
2490		DEFINE_WAIT(wait);
2491		int should_sleep = 1;
2492
2493		prepare_to_wait(&sci->sc_wait_daemon, &wait,
2494				TASK_INTERRUPTIBLE);
2495
2496		if (sci->sc_seq_request != sci->sc_seq_done)
2497			should_sleep = 0;
2498		else if (sci->sc_flush_request)
2499			should_sleep = 0;
2500		else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2501			should_sleep = time_before(jiffies,
2502					sci->sc_timer.expires);
2503
2504		if (should_sleep) {
2505			spin_unlock(&sci->sc_state_lock);
2506			schedule();
2507			spin_lock(&sci->sc_state_lock);
2508		}
2509		finish_wait(&sci->sc_wait_daemon, &wait);
2510		timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2511			   time_after_eq(jiffies, sci->sc_timer.expires));
2512
2513		if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2514			set_nilfs_discontinued(nilfs);
2515	}
2516	goto loop;
2517
2518 end_thread:
2519	spin_unlock(&sci->sc_state_lock);
2520
2521	/* end sync. */
2522	sci->sc_task = NULL;
2523	wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
 
2524	return 0;
2525}
2526
2527static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2528{
2529	struct task_struct *t;
2530
2531	t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2532	if (IS_ERR(t)) {
2533		int err = PTR_ERR(t);
2534
2535		printk(KERN_ERR "NILFS: error %d creating segctord thread\n",
2536		       err);
2537		return err;
2538	}
2539	wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2540	return 0;
2541}
2542
2543static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2544	__acquires(&sci->sc_state_lock)
2545	__releases(&sci->sc_state_lock)
2546{
2547	sci->sc_state |= NILFS_SEGCTOR_QUIT;
2548
2549	while (sci->sc_task) {
2550		wake_up(&sci->sc_wait_daemon);
2551		spin_unlock(&sci->sc_state_lock);
2552		wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2553		spin_lock(&sci->sc_state_lock);
2554	}
2555}
2556
2557/*
2558 * Setup & clean-up functions
2559 */
2560static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
2561					       struct nilfs_root *root)
2562{
2563	struct the_nilfs *nilfs = sb->s_fs_info;
2564	struct nilfs_sc_info *sci;
2565
2566	sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2567	if (!sci)
2568		return NULL;
2569
2570	sci->sc_super = sb;
2571
2572	nilfs_get_root(root);
2573	sci->sc_root = root;
2574
2575	init_waitqueue_head(&sci->sc_wait_request);
2576	init_waitqueue_head(&sci->sc_wait_daemon);
2577	init_waitqueue_head(&sci->sc_wait_task);
2578	spin_lock_init(&sci->sc_state_lock);
2579	INIT_LIST_HEAD(&sci->sc_dirty_files);
2580	INIT_LIST_HEAD(&sci->sc_segbufs);
2581	INIT_LIST_HEAD(&sci->sc_write_logs);
2582	INIT_LIST_HEAD(&sci->sc_gc_inodes);
2583	init_timer(&sci->sc_timer);
 
 
2584
2585	sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2586	sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2587	sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2588
2589	if (nilfs->ns_interval)
2590		sci->sc_interval = HZ * nilfs->ns_interval;
2591	if (nilfs->ns_watermark)
2592		sci->sc_watermark = nilfs->ns_watermark;
2593	return sci;
2594}
2595
2596static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2597{
2598	int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2599
2600	/* The segctord thread was stopped and its timer was removed.
2601	   But some tasks remain. */
 
 
2602	do {
2603		struct nilfs_transaction_info ti;
2604
2605		nilfs_transaction_lock(sci->sc_super, &ti, 0);
2606		ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2607		nilfs_transaction_unlock(sci->sc_super);
2608
2609	} while (ret && retrycount-- > 0);
 
 
2610}
2611
2612/**
2613 * nilfs_segctor_destroy - destroy the segment constructor.
2614 * @sci: nilfs_sc_info
2615 *
2616 * nilfs_segctor_destroy() kills the segctord thread and frees
2617 * the nilfs_sc_info struct.
2618 * Caller must hold the segment semaphore.
2619 */
2620static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2621{
2622	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2623	int flag;
2624
2625	up_write(&nilfs->ns_segctor_sem);
2626
2627	spin_lock(&sci->sc_state_lock);
2628	nilfs_segctor_kill_thread(sci);
2629	flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2630		|| sci->sc_seq_request != sci->sc_seq_done);
2631	spin_unlock(&sci->sc_state_lock);
2632
 
 
 
2633	if (flag || !nilfs_segctor_confirm(sci))
2634		nilfs_segctor_write_out(sci);
2635
2636	if (!list_empty(&sci->sc_dirty_files)) {
2637		nilfs_warning(sci->sc_super, __func__,
2638			      "dirty file(s) after the final construction\n");
2639		nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2640	}
2641
 
 
 
 
 
 
2642	WARN_ON(!list_empty(&sci->sc_segbufs));
2643	WARN_ON(!list_empty(&sci->sc_write_logs));
2644
2645	nilfs_put_root(sci->sc_root);
2646
2647	down_write(&nilfs->ns_segctor_sem);
2648
2649	del_timer_sync(&sci->sc_timer);
2650	kfree(sci);
2651}
2652
2653/**
2654 * nilfs_attach_log_writer - attach log writer
2655 * @sb: super block instance
2656 * @root: root object of the current filesystem tree
2657 *
2658 * This allocates a log writer object, initializes it, and starts the
2659 * log writer.
2660 *
2661 * Return Value: On success, 0 is returned. On error, one of the following
2662 * negative error code is returned.
2663 *
2664 * %-ENOMEM - Insufficient memory available.
2665 */
2666int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
2667{
2668	struct the_nilfs *nilfs = sb->s_fs_info;
2669	int err;
2670
2671	if (nilfs->ns_writer) {
2672		/*
2673		 * This happens if the filesystem was remounted
2674		 * read/write after nilfs_error degenerated it into a
2675		 * read-only mount.
 
2676		 */
2677		nilfs_detach_log_writer(sb);
2678	}
2679
2680	nilfs->ns_writer = nilfs_segctor_new(sb, root);
2681	if (!nilfs->ns_writer)
2682		return -ENOMEM;
2683
 
 
2684	err = nilfs_segctor_start_thread(nilfs->ns_writer);
2685	if (err) {
2686		kfree(nilfs->ns_writer);
2687		nilfs->ns_writer = NULL;
2688	}
2689	return err;
2690}
2691
2692/**
2693 * nilfs_detach_log_writer - destroy log writer
2694 * @sb: super block instance
2695 *
2696 * This kills log writer daemon, frees the log writer object, and
2697 * destroys list of dirty files.
2698 */
2699void nilfs_detach_log_writer(struct super_block *sb)
2700{
2701	struct the_nilfs *nilfs = sb->s_fs_info;
2702	LIST_HEAD(garbage_list);
2703
2704	down_write(&nilfs->ns_segctor_sem);
2705	if (nilfs->ns_writer) {
2706		nilfs_segctor_destroy(nilfs->ns_writer);
2707		nilfs->ns_writer = NULL;
2708	}
 
2709
2710	/* Force to free the list of dirty files */
2711	spin_lock(&nilfs->ns_inode_lock);
2712	if (!list_empty(&nilfs->ns_dirty_files)) {
2713		list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2714		nilfs_warning(sb, __func__,
2715			      "Hit dirty file after stopped log writer\n");
2716	}
2717	spin_unlock(&nilfs->ns_inode_lock);
2718	up_write(&nilfs->ns_segctor_sem);
2719
2720	nilfs_dispose_list(nilfs, &garbage_list, 1);
 
2721}