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