xref: /kernel/linux/linux-6.6/fs/nilfs2/segment.c (revision 62306a36)
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			create_empty_buffers(&folio->page, i_blocksize(inode), 0);
736			head = folio_buffers(folio);
737		}
738		folio_unlock(folio);
739
740		bh = head;
741		do {
742			if (!buffer_dirty(bh) || buffer_async_write(bh))
743				continue;
744			get_bh(bh);
745			list_add_tail(&bh->b_assoc_buffers, listp);
746			ndirties++;
747			if (unlikely(ndirties >= nlimit)) {
748				folio_batch_release(&fbatch);
749				cond_resched();
750				return ndirties;
751			}
752		} while (bh = bh->b_this_page, bh != head);
753	}
754	folio_batch_release(&fbatch);
755	cond_resched();
756	goto repeat;
757}
758
759static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
760					    struct list_head *listp)
761{
762	struct nilfs_inode_info *ii = NILFS_I(inode);
763	struct inode *btnc_inode = ii->i_assoc_inode;
764	struct folio_batch fbatch;
765	struct buffer_head *bh, *head;
766	unsigned int i;
767	pgoff_t index = 0;
768
769	if (!btnc_inode)
770		return;
771	folio_batch_init(&fbatch);
772
773	while (filemap_get_folios_tag(btnc_inode->i_mapping, &index,
774				(pgoff_t)-1, PAGECACHE_TAG_DIRTY, &fbatch)) {
775		for (i = 0; i < folio_batch_count(&fbatch); i++) {
776			bh = head = folio_buffers(fbatch.folios[i]);
777			do {
778				if (buffer_dirty(bh) &&
779						!buffer_async_write(bh)) {
780					get_bh(bh);
781					list_add_tail(&bh->b_assoc_buffers,
782						      listp);
783				}
784				bh = bh->b_this_page;
785			} while (bh != head);
786		}
787		folio_batch_release(&fbatch);
788		cond_resched();
789	}
790}
791
792static void nilfs_dispose_list(struct the_nilfs *nilfs,
793			       struct list_head *head, int force)
794{
795	struct nilfs_inode_info *ii, *n;
796	struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
797	unsigned int nv = 0;
798
799	while (!list_empty(head)) {
800		spin_lock(&nilfs->ns_inode_lock);
801		list_for_each_entry_safe(ii, n, head, i_dirty) {
802			list_del_init(&ii->i_dirty);
803			if (force) {
804				if (unlikely(ii->i_bh)) {
805					brelse(ii->i_bh);
806					ii->i_bh = NULL;
807				}
808			} else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
809				set_bit(NILFS_I_QUEUED, &ii->i_state);
810				list_add_tail(&ii->i_dirty,
811					      &nilfs->ns_dirty_files);
812				continue;
813			}
814			ivec[nv++] = ii;
815			if (nv == SC_N_INODEVEC)
816				break;
817		}
818		spin_unlock(&nilfs->ns_inode_lock);
819
820		for (pii = ivec; nv > 0; pii++, nv--)
821			iput(&(*pii)->vfs_inode);
822	}
823}
824
825static void nilfs_iput_work_func(struct work_struct *work)
826{
827	struct nilfs_sc_info *sci = container_of(work, struct nilfs_sc_info,
828						 sc_iput_work);
829	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
830
831	nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 0);
832}
833
834static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
835				     struct nilfs_root *root)
836{
837	int ret = 0;
838
839	if (nilfs_mdt_fetch_dirty(root->ifile))
840		ret++;
841	if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
842		ret++;
843	if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
844		ret++;
845	if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
846		ret++;
847	return ret;
848}
849
850static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
851{
852	return list_empty(&sci->sc_dirty_files) &&
853		!test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
854		sci->sc_nfreesegs == 0 &&
855		(!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
856}
857
858static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
859{
860	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
861	int ret = 0;
862
863	if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
864		set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
865
866	spin_lock(&nilfs->ns_inode_lock);
867	if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
868		ret++;
869
870	spin_unlock(&nilfs->ns_inode_lock);
871	return ret;
872}
873
874static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
875{
876	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
877
878	nilfs_mdt_clear_dirty(sci->sc_root->ifile);
879	nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
880	nilfs_mdt_clear_dirty(nilfs->ns_sufile);
881	nilfs_mdt_clear_dirty(nilfs->ns_dat);
882}
883
884static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
885{
886	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
887	struct buffer_head *bh_cp;
888	struct nilfs_checkpoint *raw_cp;
889	int err;
890
891	/* XXX: this interface will be changed */
892	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 1,
893					  &raw_cp, &bh_cp);
894	if (likely(!err)) {
895		/*
896		 * The following code is duplicated with cpfile.  But, it is
897		 * needed to collect the checkpoint even if it was not newly
898		 * created.
899		 */
900		mark_buffer_dirty(bh_cp);
901		nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
902		nilfs_cpfile_put_checkpoint(
903			nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
904	} else if (err == -EINVAL || err == -ENOENT) {
905		nilfs_error(sci->sc_super,
906			    "checkpoint creation failed due to metadata corruption.");
907		err = -EIO;
908	}
909	return err;
910}
911
912static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
913{
914	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
915	struct buffer_head *bh_cp;
916	struct nilfs_checkpoint *raw_cp;
917	int err;
918
919	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
920					  &raw_cp, &bh_cp);
921	if (unlikely(err)) {
922		if (err == -EINVAL || err == -ENOENT) {
923			nilfs_error(sci->sc_super,
924				    "checkpoint finalization failed due to metadata corruption.");
925			err = -EIO;
926		}
927		goto failed_ibh;
928	}
929	raw_cp->cp_snapshot_list.ssl_next = 0;
930	raw_cp->cp_snapshot_list.ssl_prev = 0;
931	raw_cp->cp_inodes_count =
932		cpu_to_le64(atomic64_read(&sci->sc_root->inodes_count));
933	raw_cp->cp_blocks_count =
934		cpu_to_le64(atomic64_read(&sci->sc_root->blocks_count));
935	raw_cp->cp_nblk_inc =
936		cpu_to_le64(sci->sc_nblk_inc + sci->sc_nblk_this_inc);
937	raw_cp->cp_create = cpu_to_le64(sci->sc_seg_ctime);
938	raw_cp->cp_cno = cpu_to_le64(nilfs->ns_cno);
939
940	if (test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
941		nilfs_checkpoint_clear_minor(raw_cp);
942	else
943		nilfs_checkpoint_set_minor(raw_cp);
944
945	nilfs_write_inode_common(sci->sc_root->ifile,
946				 &raw_cp->cp_ifile_inode, 1);
947	nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
948	return 0;
949
950 failed_ibh:
951	return err;
952}
953
954static void nilfs_fill_in_file_bmap(struct inode *ifile,
955				    struct nilfs_inode_info *ii)
956
957{
958	struct buffer_head *ibh;
959	struct nilfs_inode *raw_inode;
960
961	if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
962		ibh = ii->i_bh;
963		BUG_ON(!ibh);
964		raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
965						  ibh);
966		nilfs_bmap_write(ii->i_bmap, raw_inode);
967		nilfs_ifile_unmap_inode(ifile, ii->vfs_inode.i_ino, ibh);
968	}
969}
970
971static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
972{
973	struct nilfs_inode_info *ii;
974
975	list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
976		nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
977		set_bit(NILFS_I_COLLECTED, &ii->i_state);
978	}
979}
980
981static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
982					     struct the_nilfs *nilfs)
983{
984	struct buffer_head *bh_sr;
985	struct nilfs_super_root *raw_sr;
986	unsigned int isz, srsz;
987
988	bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
989
990	lock_buffer(bh_sr);
991	raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
992	isz = nilfs->ns_inode_size;
993	srsz = NILFS_SR_BYTES(isz);
994
995	raw_sr->sr_sum = 0;  /* Ensure initialization within this update */
996	raw_sr->sr_bytes = cpu_to_le16(srsz);
997	raw_sr->sr_nongc_ctime
998		= cpu_to_le64(nilfs_doing_gc() ?
999			      nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
1000	raw_sr->sr_flags = 0;
1001
1002	nilfs_write_inode_common(nilfs->ns_dat, (void *)raw_sr +
1003				 NILFS_SR_DAT_OFFSET(isz), 1);
1004	nilfs_write_inode_common(nilfs->ns_cpfile, (void *)raw_sr +
1005				 NILFS_SR_CPFILE_OFFSET(isz), 1);
1006	nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
1007				 NILFS_SR_SUFILE_OFFSET(isz), 1);
1008	memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
1009	set_buffer_uptodate(bh_sr);
1010	unlock_buffer(bh_sr);
1011}
1012
1013static void nilfs_redirty_inodes(struct list_head *head)
1014{
1015	struct nilfs_inode_info *ii;
1016
1017	list_for_each_entry(ii, head, i_dirty) {
1018		if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
1019			clear_bit(NILFS_I_COLLECTED, &ii->i_state);
1020	}
1021}
1022
1023static void nilfs_drop_collected_inodes(struct list_head *head)
1024{
1025	struct nilfs_inode_info *ii;
1026
1027	list_for_each_entry(ii, head, i_dirty) {
1028		if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
1029			continue;
1030
1031		clear_bit(NILFS_I_INODE_SYNC, &ii->i_state);
1032		set_bit(NILFS_I_UPDATED, &ii->i_state);
1033	}
1034}
1035
1036static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
1037				       struct inode *inode,
1038				       struct list_head *listp,
1039				       int (*collect)(struct nilfs_sc_info *,
1040						      struct buffer_head *,
1041						      struct inode *))
1042{
1043	struct buffer_head *bh, *n;
1044	int err = 0;
1045
1046	if (collect) {
1047		list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
1048			list_del_init(&bh->b_assoc_buffers);
1049			err = collect(sci, bh, inode);
1050			brelse(bh);
1051			if (unlikely(err))
1052				goto dispose_buffers;
1053		}
1054		return 0;
1055	}
1056
1057 dispose_buffers:
1058	while (!list_empty(listp)) {
1059		bh = list_first_entry(listp, struct buffer_head,
1060				      b_assoc_buffers);
1061		list_del_init(&bh->b_assoc_buffers);
1062		brelse(bh);
1063	}
1064	return err;
1065}
1066
1067static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
1068{
1069	/* Remaining number of blocks within segment buffer */
1070	return sci->sc_segbuf_nblocks -
1071		(sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
1072}
1073
1074static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
1075				   struct inode *inode,
1076				   const struct nilfs_sc_operations *sc_ops)
1077{
1078	LIST_HEAD(data_buffers);
1079	LIST_HEAD(node_buffers);
1080	int err;
1081
1082	if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1083		size_t n, rest = nilfs_segctor_buffer_rest(sci);
1084
1085		n = nilfs_lookup_dirty_data_buffers(
1086			inode, &data_buffers, rest + 1, 0, LLONG_MAX);
1087		if (n > rest) {
1088			err = nilfs_segctor_apply_buffers(
1089				sci, inode, &data_buffers,
1090				sc_ops->collect_data);
1091			BUG_ON(!err); /* always receive -E2BIG or true error */
1092			goto break_or_fail;
1093		}
1094	}
1095	nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
1096
1097	if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
1098		err = nilfs_segctor_apply_buffers(
1099			sci, inode, &data_buffers, sc_ops->collect_data);
1100		if (unlikely(err)) {
1101			/* dispose node list */
1102			nilfs_segctor_apply_buffers(
1103				sci, inode, &node_buffers, NULL);
1104			goto break_or_fail;
1105		}
1106		sci->sc_stage.flags |= NILFS_CF_NODE;
1107	}
1108	/* Collect node */
1109	err = nilfs_segctor_apply_buffers(
1110		sci, inode, &node_buffers, sc_ops->collect_node);
1111	if (unlikely(err))
1112		goto break_or_fail;
1113
1114	nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1115	err = nilfs_segctor_apply_buffers(
1116		sci, inode, &node_buffers, sc_ops->collect_bmap);
1117	if (unlikely(err))
1118		goto break_or_fail;
1119
1120	nilfs_segctor_end_finfo(sci, inode);
1121	sci->sc_stage.flags &= ~NILFS_CF_NODE;
1122
1123 break_or_fail:
1124	return err;
1125}
1126
1127static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1128					 struct inode *inode)
1129{
1130	LIST_HEAD(data_buffers);
1131	size_t n, rest = nilfs_segctor_buffer_rest(sci);
1132	int err;
1133
1134	n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1135					    sci->sc_dsync_start,
1136					    sci->sc_dsync_end);
1137
1138	err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1139					  nilfs_collect_file_data);
1140	if (!err) {
1141		nilfs_segctor_end_finfo(sci, inode);
1142		BUG_ON(n > rest);
1143		/* always receive -E2BIG or true error if n > rest */
1144	}
1145	return err;
1146}
1147
1148static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1149{
1150	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
1151	struct list_head *head;
1152	struct nilfs_inode_info *ii;
1153	size_t ndone;
1154	int err = 0;
1155
1156	switch (nilfs_sc_cstage_get(sci)) {
1157	case NILFS_ST_INIT:
1158		/* Pre-processes */
1159		sci->sc_stage.flags = 0;
1160
1161		if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1162			sci->sc_nblk_inc = 0;
1163			sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1164			if (mode == SC_LSEG_DSYNC) {
1165				nilfs_sc_cstage_set(sci, NILFS_ST_DSYNC);
1166				goto dsync_mode;
1167			}
1168		}
1169
1170		sci->sc_stage.dirty_file_ptr = NULL;
1171		sci->sc_stage.gc_inode_ptr = NULL;
1172		if (mode == SC_FLUSH_DAT) {
1173			nilfs_sc_cstage_set(sci, NILFS_ST_DAT);
1174			goto dat_stage;
1175		}
1176		nilfs_sc_cstage_inc(sci);
1177		fallthrough;
1178	case NILFS_ST_GC:
1179		if (nilfs_doing_gc()) {
1180			head = &sci->sc_gc_inodes;
1181			ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1182						head, i_dirty);
1183			list_for_each_entry_continue(ii, head, i_dirty) {
1184				err = nilfs_segctor_scan_file(
1185					sci, &ii->vfs_inode,
1186					&nilfs_sc_file_ops);
1187				if (unlikely(err)) {
1188					sci->sc_stage.gc_inode_ptr = list_entry(
1189						ii->i_dirty.prev,
1190						struct nilfs_inode_info,
1191						i_dirty);
1192					goto break_or_fail;
1193				}
1194				set_bit(NILFS_I_COLLECTED, &ii->i_state);
1195			}
1196			sci->sc_stage.gc_inode_ptr = NULL;
1197		}
1198		nilfs_sc_cstage_inc(sci);
1199		fallthrough;
1200	case NILFS_ST_FILE:
1201		head = &sci->sc_dirty_files;
1202		ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1203					i_dirty);
1204		list_for_each_entry_continue(ii, head, i_dirty) {
1205			clear_bit(NILFS_I_DIRTY, &ii->i_state);
1206
1207			err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1208						      &nilfs_sc_file_ops);
1209			if (unlikely(err)) {
1210				sci->sc_stage.dirty_file_ptr =
1211					list_entry(ii->i_dirty.prev,
1212						   struct nilfs_inode_info,
1213						   i_dirty);
1214				goto break_or_fail;
1215			}
1216			/* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1217			/* XXX: required ? */
1218		}
1219		sci->sc_stage.dirty_file_ptr = NULL;
1220		if (mode == SC_FLUSH_FILE) {
1221			nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1222			return 0;
1223		}
1224		nilfs_sc_cstage_inc(sci);
1225		sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1226		fallthrough;
1227	case NILFS_ST_IFILE:
1228		err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1229					      &nilfs_sc_file_ops);
1230		if (unlikely(err))
1231			break;
1232		nilfs_sc_cstage_inc(sci);
1233		/* Creating a checkpoint */
1234		err = nilfs_segctor_create_checkpoint(sci);
1235		if (unlikely(err))
1236			break;
1237		fallthrough;
1238	case NILFS_ST_CPFILE:
1239		err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1240					      &nilfs_sc_file_ops);
1241		if (unlikely(err))
1242			break;
1243		nilfs_sc_cstage_inc(sci);
1244		fallthrough;
1245	case NILFS_ST_SUFILE:
1246		err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1247					 sci->sc_nfreesegs, &ndone);
1248		if (unlikely(err)) {
1249			nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1250						  sci->sc_freesegs, ndone,
1251						  NULL);
1252			break;
1253		}
1254		sci->sc_stage.flags |= NILFS_CF_SUFREED;
1255
1256		err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1257					      &nilfs_sc_file_ops);
1258		if (unlikely(err))
1259			break;
1260		nilfs_sc_cstage_inc(sci);
1261		fallthrough;
1262	case NILFS_ST_DAT:
1263 dat_stage:
1264		err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1265					      &nilfs_sc_dat_ops);
1266		if (unlikely(err))
1267			break;
1268		if (mode == SC_FLUSH_DAT) {
1269			nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1270			return 0;
1271		}
1272		nilfs_sc_cstage_inc(sci);
1273		fallthrough;
1274	case NILFS_ST_SR:
1275		if (mode == SC_LSEG_SR) {
1276			/* Appending a super root */
1277			err = nilfs_segctor_add_super_root(sci);
1278			if (unlikely(err))
1279				break;
1280		}
1281		/* End of a logical segment */
1282		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1283		nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1284		return 0;
1285	case NILFS_ST_DSYNC:
1286 dsync_mode:
1287		sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1288		ii = sci->sc_dsync_inode;
1289		if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1290			break;
1291
1292		err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1293		if (unlikely(err))
1294			break;
1295		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1296		nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
1297		return 0;
1298	case NILFS_ST_DONE:
1299		return 0;
1300	default:
1301		BUG();
1302	}
1303
1304 break_or_fail:
1305	return err;
1306}
1307
1308/**
1309 * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1310 * @sci: nilfs_sc_info
1311 * @nilfs: nilfs object
1312 */
1313static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1314					    struct the_nilfs *nilfs)
1315{
1316	struct nilfs_segment_buffer *segbuf, *prev;
1317	__u64 nextnum;
1318	int err, alloc = 0;
1319
1320	segbuf = nilfs_segbuf_new(sci->sc_super);
1321	if (unlikely(!segbuf))
1322		return -ENOMEM;
1323
1324	if (list_empty(&sci->sc_write_logs)) {
1325		nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1326				 nilfs->ns_pseg_offset, nilfs);
1327		if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1328			nilfs_shift_to_next_segment(nilfs);
1329			nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1330		}
1331
1332		segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1333		nextnum = nilfs->ns_nextnum;
1334
1335		if (nilfs->ns_segnum == nilfs->ns_nextnum)
1336			/* Start from the head of a new full segment */
1337			alloc++;
1338	} else {
1339		/* Continue logs */
1340		prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1341		nilfs_segbuf_map_cont(segbuf, prev);
1342		segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1343		nextnum = prev->sb_nextnum;
1344
1345		if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1346			nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1347			segbuf->sb_sum.seg_seq++;
1348			alloc++;
1349		}
1350	}
1351
1352	err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1353	if (err)
1354		goto failed;
1355
1356	if (alloc) {
1357		err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1358		if (err)
1359			goto failed;
1360	}
1361	nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1362
1363	BUG_ON(!list_empty(&sci->sc_segbufs));
1364	list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1365	sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1366	return 0;
1367
1368 failed:
1369	nilfs_segbuf_free(segbuf);
1370	return err;
1371}
1372
1373static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1374					 struct the_nilfs *nilfs, int nadd)
1375{
1376	struct nilfs_segment_buffer *segbuf, *prev;
1377	struct inode *sufile = nilfs->ns_sufile;
1378	__u64 nextnextnum;
1379	LIST_HEAD(list);
1380	int err, ret, i;
1381
1382	prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1383	/*
1384	 * Since the segment specified with nextnum might be allocated during
1385	 * the previous construction, the buffer including its segusage may
1386	 * not be dirty.  The following call ensures that the buffer is dirty
1387	 * and will pin the buffer on memory until the sufile is written.
1388	 */
1389	err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1390	if (unlikely(err))
1391		return err;
1392
1393	for (i = 0; i < nadd; i++) {
1394		/* extend segment info */
1395		err = -ENOMEM;
1396		segbuf = nilfs_segbuf_new(sci->sc_super);
1397		if (unlikely(!segbuf))
1398			goto failed;
1399
1400		/* map this buffer to region of segment on-disk */
1401		nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1402		sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1403
1404		/* allocate the next next full segment */
1405		err = nilfs_sufile_alloc(sufile, &nextnextnum);
1406		if (unlikely(err))
1407			goto failed_segbuf;
1408
1409		segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1410		nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1411
1412		list_add_tail(&segbuf->sb_list, &list);
1413		prev = segbuf;
1414	}
1415	list_splice_tail(&list, &sci->sc_segbufs);
1416	return 0;
1417
1418 failed_segbuf:
1419	nilfs_segbuf_free(segbuf);
1420 failed:
1421	list_for_each_entry(segbuf, &list, sb_list) {
1422		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1423		WARN_ON(ret); /* never fails */
1424	}
1425	nilfs_destroy_logs(&list);
1426	return err;
1427}
1428
1429static void nilfs_free_incomplete_logs(struct list_head *logs,
1430				       struct the_nilfs *nilfs)
1431{
1432	struct nilfs_segment_buffer *segbuf, *prev;
1433	struct inode *sufile = nilfs->ns_sufile;
1434	int ret;
1435
1436	segbuf = NILFS_FIRST_SEGBUF(logs);
1437	if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1438		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1439		WARN_ON(ret); /* never fails */
1440	}
1441	if (atomic_read(&segbuf->sb_err)) {
1442		/* Case 1: The first segment failed */
1443		if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1444			/*
1445			 * Case 1a:  Partial segment appended into an existing
1446			 * segment
1447			 */
1448			nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1449						segbuf->sb_fseg_end);
1450		else /* Case 1b:  New full segment */
1451			set_nilfs_discontinued(nilfs);
1452	}
1453
1454	prev = segbuf;
1455	list_for_each_entry_continue(segbuf, logs, sb_list) {
1456		if (prev->sb_nextnum != segbuf->sb_nextnum) {
1457			ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1458			WARN_ON(ret); /* never fails */
1459		}
1460		if (atomic_read(&segbuf->sb_err) &&
1461		    segbuf->sb_segnum != nilfs->ns_nextnum)
1462			/* Case 2: extended segment (!= next) failed */
1463			nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1464		prev = segbuf;
1465	}
1466}
1467
1468static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1469					  struct inode *sufile)
1470{
1471	struct nilfs_segment_buffer *segbuf;
1472	unsigned long live_blocks;
1473	int ret;
1474
1475	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1476		live_blocks = segbuf->sb_sum.nblocks +
1477			(segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1478		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1479						     live_blocks,
1480						     sci->sc_seg_ctime);
1481		WARN_ON(ret); /* always succeed because the segusage is dirty */
1482	}
1483}
1484
1485static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1486{
1487	struct nilfs_segment_buffer *segbuf;
1488	int ret;
1489
1490	segbuf = NILFS_FIRST_SEGBUF(logs);
1491	ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1492					     segbuf->sb_pseg_start -
1493					     segbuf->sb_fseg_start, 0);
1494	WARN_ON(ret); /* always succeed because the segusage is dirty */
1495
1496	list_for_each_entry_continue(segbuf, logs, sb_list) {
1497		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1498						     0, 0);
1499		WARN_ON(ret); /* always succeed */
1500	}
1501}
1502
1503static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1504					    struct nilfs_segment_buffer *last,
1505					    struct inode *sufile)
1506{
1507	struct nilfs_segment_buffer *segbuf = last;
1508	int ret;
1509
1510	list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1511		sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1512		ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1513		WARN_ON(ret);
1514	}
1515	nilfs_truncate_logs(&sci->sc_segbufs, last);
1516}
1517
1518
1519static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1520				 struct the_nilfs *nilfs, int mode)
1521{
1522	struct nilfs_cstage prev_stage = sci->sc_stage;
1523	int err, nadd = 1;
1524
1525	/* Collection retry loop */
1526	for (;;) {
1527		sci->sc_nblk_this_inc = 0;
1528		sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1529
1530		err = nilfs_segctor_reset_segment_buffer(sci);
1531		if (unlikely(err))
1532			goto failed;
1533
1534		err = nilfs_segctor_collect_blocks(sci, mode);
1535		sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1536		if (!err)
1537			break;
1538
1539		if (unlikely(err != -E2BIG))
1540			goto failed;
1541
1542		/* The current segment is filled up */
1543		if (mode != SC_LSEG_SR ||
1544		    nilfs_sc_cstage_get(sci) < NILFS_ST_CPFILE)
1545			break;
1546
1547		nilfs_clear_logs(&sci->sc_segbufs);
1548
1549		if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1550			err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1551							sci->sc_freesegs,
1552							sci->sc_nfreesegs,
1553							NULL);
1554			WARN_ON(err); /* do not happen */
1555			sci->sc_stage.flags &= ~NILFS_CF_SUFREED;
1556		}
1557
1558		err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1559		if (unlikely(err))
1560			return err;
1561
1562		nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1563		sci->sc_stage = prev_stage;
1564	}
1565	nilfs_segctor_zeropad_segsum(sci);
1566	nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1567	return 0;
1568
1569 failed:
1570	return err;
1571}
1572
1573static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1574				      struct buffer_head *new_bh)
1575{
1576	BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1577
1578	list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1579	/* The caller must release old_bh */
1580}
1581
1582static int
1583nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1584				     struct nilfs_segment_buffer *segbuf,
1585				     int mode)
1586{
1587	struct inode *inode = NULL;
1588	sector_t blocknr;
1589	unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1590	unsigned long nblocks = 0, ndatablk = 0;
1591	const struct nilfs_sc_operations *sc_op = NULL;
1592	struct nilfs_segsum_pointer ssp;
1593	struct nilfs_finfo *finfo = NULL;
1594	union nilfs_binfo binfo;
1595	struct buffer_head *bh, *bh_org;
1596	ino_t ino = 0;
1597	int err = 0;
1598
1599	if (!nfinfo)
1600		goto out;
1601
1602	blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1603	ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1604	ssp.offset = sizeof(struct nilfs_segment_summary);
1605
1606	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1607		if (bh == segbuf->sb_super_root)
1608			break;
1609		if (!finfo) {
1610			finfo =	nilfs_segctor_map_segsum_entry(
1611				sci, &ssp, sizeof(*finfo));
1612			ino = le64_to_cpu(finfo->fi_ino);
1613			nblocks = le32_to_cpu(finfo->fi_nblocks);
1614			ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1615
1616			inode = bh->b_folio->mapping->host;
1617
1618			if (mode == SC_LSEG_DSYNC)
1619				sc_op = &nilfs_sc_dsync_ops;
1620			else if (ino == NILFS_DAT_INO)
1621				sc_op = &nilfs_sc_dat_ops;
1622			else /* file blocks */
1623				sc_op = &nilfs_sc_file_ops;
1624		}
1625		bh_org = bh;
1626		get_bh(bh_org);
1627		err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1628					&binfo);
1629		if (bh != bh_org)
1630			nilfs_list_replace_buffer(bh_org, bh);
1631		brelse(bh_org);
1632		if (unlikely(err))
1633			goto failed_bmap;
1634
1635		if (ndatablk > 0)
1636			sc_op->write_data_binfo(sci, &ssp, &binfo);
1637		else
1638			sc_op->write_node_binfo(sci, &ssp, &binfo);
1639
1640		blocknr++;
1641		if (--nblocks == 0) {
1642			finfo = NULL;
1643			if (--nfinfo == 0)
1644				break;
1645		} else if (ndatablk > 0)
1646			ndatablk--;
1647	}
1648 out:
1649	return 0;
1650
1651 failed_bmap:
1652	return err;
1653}
1654
1655static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1656{
1657	struct nilfs_segment_buffer *segbuf;
1658	int err;
1659
1660	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1661		err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1662		if (unlikely(err))
1663			return err;
1664		nilfs_segbuf_fill_in_segsum(segbuf);
1665	}
1666	return 0;
1667}
1668
1669static void nilfs_begin_page_io(struct page *page)
1670{
1671	if (!page || PageWriteback(page))
1672		/*
1673		 * For split b-tree node pages, this function may be called
1674		 * twice.  We ignore the 2nd or later calls by this check.
1675		 */
1676		return;
1677
1678	lock_page(page);
1679	clear_page_dirty_for_io(page);
1680	set_page_writeback(page);
1681	unlock_page(page);
1682}
1683
1684static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci)
1685{
1686	struct nilfs_segment_buffer *segbuf;
1687	struct page *bd_page = NULL, *fs_page = NULL;
1688
1689	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1690		struct buffer_head *bh;
1691
1692		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1693				    b_assoc_buffers) {
1694			if (bh->b_page != bd_page) {
1695				if (bd_page) {
1696					lock_page(bd_page);
1697					clear_page_dirty_for_io(bd_page);
1698					set_page_writeback(bd_page);
1699					unlock_page(bd_page);
1700				}
1701				bd_page = bh->b_page;
1702			}
1703		}
1704
1705		list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1706				    b_assoc_buffers) {
1707			if (bh == segbuf->sb_super_root) {
1708				if (bh->b_page != bd_page) {
1709					lock_page(bd_page);
1710					clear_page_dirty_for_io(bd_page);
1711					set_page_writeback(bd_page);
1712					unlock_page(bd_page);
1713					bd_page = bh->b_page;
1714				}
1715				break;
1716			}
1717			set_buffer_async_write(bh);
1718			if (bh->b_page != fs_page) {
1719				nilfs_begin_page_io(fs_page);
1720				fs_page = bh->b_page;
1721			}
1722		}
1723	}
1724	if (bd_page) {
1725		lock_page(bd_page);
1726		clear_page_dirty_for_io(bd_page);
1727		set_page_writeback(bd_page);
1728		unlock_page(bd_page);
1729	}
1730	nilfs_begin_page_io(fs_page);
1731}
1732
1733static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1734			       struct the_nilfs *nilfs)
1735{
1736	int ret;
1737
1738	ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1739	list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1740	return ret;
1741}
1742
1743static void nilfs_end_page_io(struct page *page, int err)
1744{
1745	if (!page)
1746		return;
1747
1748	if (buffer_nilfs_node(page_buffers(page)) && !PageWriteback(page)) {
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 (PageDirty(page)) {
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			lock_page(page);
1762			if (nilfs_page_buffers_clean(page))
1763				__nilfs_clear_page_dirty(page);
1764			unlock_page(page);
1765		}
1766		return;
1767	}
1768
1769	if (!err) {
1770		if (!nilfs_page_buffers_clean(page))
1771			__set_page_dirty_nobuffers(page);
1772		ClearPageError(page);
1773	} else {
1774		__set_page_dirty_nobuffers(page);
1775		SetPageError(page);
1776	}
1777
1778	end_page_writeback(page);
1779}
1780
1781static void nilfs_abort_logs(struct list_head *logs, int err)
1782{
1783	struct nilfs_segment_buffer *segbuf;
1784	struct page *bd_page = NULL, *fs_page = 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_page != bd_page) {
1795				if (bd_page)
1796					end_page_writeback(bd_page);
1797				bd_page = bh->b_page;
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_page != bd_page) {
1806					end_page_writeback(bd_page);
1807					bd_page = bh->b_page;
1808				}
1809				break;
1810			}
1811			clear_buffer_async_write(bh);
1812			if (bh->b_page != fs_page) {
1813				nilfs_end_page_io(fs_page, err);
1814				fs_page = bh->b_page;
1815			}
1816		}
1817	}
1818	if (bd_page)
1819		end_page_writeback(bd_page);
1820
1821	nilfs_end_page_io(fs_page, 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 page *bd_page = NULL, *fs_page = 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_page != bd_page) {
1875				if (bd_page)
1876					end_page_writeback(bd_page);
1877				bd_page = bh->b_page;
1878			}
1879		}
1880		/*
1881		 * We assume that the buffers which belong to the same page
1882		 * continue over the buffer list.
1883		 * Under this assumption, the last BHs of pages is
1884		 * identifiable by the discontinuity of bh->b_page
1885		 * (page != fs_page).
1886		 *
1887		 * For B-tree node blocks, however, this assumption is not
1888		 * guaranteed.  The cleanup code of B-tree node pages 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_page != bd_page) {
1903					end_page_writeback(bd_page);
1904					bd_page = bh->b_page;
1905				}
1906				update_sr = true;
1907				break;
1908			}
1909			set_mask_bits(&bh->b_state, clear_bits, set_bits);
1910			if (bh->b_page != fs_page) {
1911				nilfs_end_page_io(fs_page, 0);
1912				fs_page = bh->b_page;
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 pages may continue over multiple segment buffers,
1927	 * end of the last page must be checked outside of the loop.
1928	 */
1929	if (bd_page)
1930		end_page_writeback(bd_page);
1931
1932	nilfs_end_page_io(fs_page, 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	spin_lock(&sci->sc_state_lock);
2594 loop:
2595	for (;;) {
2596		int mode;
2597
2598		if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2599			goto end_thread;
2600
2601		if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2602			mode = SC_LSEG_SR;
2603		else if (sci->sc_flush_request)
2604			mode = nilfs_segctor_flush_mode(sci);
2605		else
2606			break;
2607
2608		spin_unlock(&sci->sc_state_lock);
2609		nilfs_segctor_thread_construct(sci, mode);
2610		spin_lock(&sci->sc_state_lock);
2611		timeout = 0;
2612	}
2613
2614
2615	if (freezing(current)) {
2616		spin_unlock(&sci->sc_state_lock);
2617		try_to_freeze();
2618		spin_lock(&sci->sc_state_lock);
2619	} else {
2620		DEFINE_WAIT(wait);
2621		int should_sleep = 1;
2622
2623		prepare_to_wait(&sci->sc_wait_daemon, &wait,
2624				TASK_INTERRUPTIBLE);
2625
2626		if (sci->sc_seq_request != sci->sc_seq_done)
2627			should_sleep = 0;
2628		else if (sci->sc_flush_request)
2629			should_sleep = 0;
2630		else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2631			should_sleep = time_before(jiffies,
2632					sci->sc_timer.expires);
2633
2634		if (should_sleep) {
2635			spin_unlock(&sci->sc_state_lock);
2636			schedule();
2637			spin_lock(&sci->sc_state_lock);
2638		}
2639		finish_wait(&sci->sc_wait_daemon, &wait);
2640		timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2641			   time_after_eq(jiffies, sci->sc_timer.expires));
2642
2643		if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2644			set_nilfs_discontinued(nilfs);
2645	}
2646	goto loop;
2647
2648 end_thread:
2649	/* end sync. */
2650	sci->sc_task = NULL;
2651	wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
2652	spin_unlock(&sci->sc_state_lock);
2653	return 0;
2654}
2655
2656static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2657{
2658	struct task_struct *t;
2659
2660	t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2661	if (IS_ERR(t)) {
2662		int err = PTR_ERR(t);
2663
2664		nilfs_err(sci->sc_super, "error %d creating segctord thread",
2665			  err);
2666		return err;
2667	}
2668	wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2669	return 0;
2670}
2671
2672static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2673	__acquires(&sci->sc_state_lock)
2674	__releases(&sci->sc_state_lock)
2675{
2676	sci->sc_state |= NILFS_SEGCTOR_QUIT;
2677
2678	while (sci->sc_task) {
2679		wake_up(&sci->sc_wait_daemon);
2680		spin_unlock(&sci->sc_state_lock);
2681		wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2682		spin_lock(&sci->sc_state_lock);
2683	}
2684}
2685
2686/*
2687 * Setup & clean-up functions
2688 */
2689static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
2690					       struct nilfs_root *root)
2691{
2692	struct the_nilfs *nilfs = sb->s_fs_info;
2693	struct nilfs_sc_info *sci;
2694
2695	sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2696	if (!sci)
2697		return NULL;
2698
2699	sci->sc_super = sb;
2700
2701	nilfs_get_root(root);
2702	sci->sc_root = root;
2703
2704	init_waitqueue_head(&sci->sc_wait_request);
2705	init_waitqueue_head(&sci->sc_wait_daemon);
2706	init_waitqueue_head(&sci->sc_wait_task);
2707	spin_lock_init(&sci->sc_state_lock);
2708	INIT_LIST_HEAD(&sci->sc_dirty_files);
2709	INIT_LIST_HEAD(&sci->sc_segbufs);
2710	INIT_LIST_HEAD(&sci->sc_write_logs);
2711	INIT_LIST_HEAD(&sci->sc_gc_inodes);
2712	INIT_LIST_HEAD(&sci->sc_iput_queue);
2713	INIT_WORK(&sci->sc_iput_work, nilfs_iput_work_func);
2714	timer_setup(&sci->sc_timer, nilfs_construction_timeout, 0);
2715
2716	sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2717	sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2718	sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2719
2720	if (nilfs->ns_interval)
2721		sci->sc_interval = HZ * nilfs->ns_interval;
2722	if (nilfs->ns_watermark)
2723		sci->sc_watermark = nilfs->ns_watermark;
2724	return sci;
2725}
2726
2727static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2728{
2729	int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2730
2731	/*
2732	 * The segctord thread was stopped and its timer was removed.
2733	 * But some tasks remain.
2734	 */
2735	do {
2736		struct nilfs_transaction_info ti;
2737
2738		nilfs_transaction_lock(sci->sc_super, &ti, 0);
2739		ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2740		nilfs_transaction_unlock(sci->sc_super);
2741
2742		flush_work(&sci->sc_iput_work);
2743
2744	} while (ret && ret != -EROFS && retrycount-- > 0);
2745}
2746
2747/**
2748 * nilfs_segctor_destroy - destroy the segment constructor.
2749 * @sci: nilfs_sc_info
2750 *
2751 * nilfs_segctor_destroy() kills the segctord thread and frees
2752 * the nilfs_sc_info struct.
2753 * Caller must hold the segment semaphore.
2754 */
2755static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2756{
2757	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
2758	int flag;
2759
2760	up_write(&nilfs->ns_segctor_sem);
2761
2762	spin_lock(&sci->sc_state_lock);
2763	nilfs_segctor_kill_thread(sci);
2764	flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2765		|| sci->sc_seq_request != sci->sc_seq_done);
2766	spin_unlock(&sci->sc_state_lock);
2767
2768	if (flush_work(&sci->sc_iput_work))
2769		flag = true;
2770
2771	if (flag || !nilfs_segctor_confirm(sci))
2772		nilfs_segctor_write_out(sci);
2773
2774	if (!list_empty(&sci->sc_dirty_files)) {
2775		nilfs_warn(sci->sc_super,
2776			   "disposed unprocessed dirty file(s) when stopping log writer");
2777		nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2778	}
2779
2780	if (!list_empty(&sci->sc_iput_queue)) {
2781		nilfs_warn(sci->sc_super,
2782			   "disposed unprocessed inode(s) in iput queue when stopping log writer");
2783		nilfs_dispose_list(nilfs, &sci->sc_iput_queue, 1);
2784	}
2785
2786	WARN_ON(!list_empty(&sci->sc_segbufs));
2787	WARN_ON(!list_empty(&sci->sc_write_logs));
2788
2789	nilfs_put_root(sci->sc_root);
2790
2791	down_write(&nilfs->ns_segctor_sem);
2792
2793	timer_shutdown_sync(&sci->sc_timer);
2794	kfree(sci);
2795}
2796
2797/**
2798 * nilfs_attach_log_writer - attach log writer
2799 * @sb: super block instance
2800 * @root: root object of the current filesystem tree
2801 *
2802 * This allocates a log writer object, initializes it, and starts the
2803 * log writer.
2804 *
2805 * Return Value: On success, 0 is returned. On error, one of the following
2806 * negative error code is returned.
2807 *
2808 * %-ENOMEM - Insufficient memory available.
2809 */
2810int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
2811{
2812	struct the_nilfs *nilfs = sb->s_fs_info;
2813	int err;
2814
2815	if (nilfs->ns_writer) {
2816		/*
2817		 * This happens if the filesystem is made read-only by
2818		 * __nilfs_error or nilfs_remount and then remounted
2819		 * read/write.  In these cases, reuse the existing
2820		 * writer.
2821		 */
2822		return 0;
2823	}
2824
2825	nilfs->ns_writer = nilfs_segctor_new(sb, root);
2826	if (!nilfs->ns_writer)
2827		return -ENOMEM;
2828
2829	inode_attach_wb(nilfs->ns_bdev->bd_inode, NULL);
2830
2831	err = nilfs_segctor_start_thread(nilfs->ns_writer);
2832	if (unlikely(err))
2833		nilfs_detach_log_writer(sb);
2834
2835	return err;
2836}
2837
2838/**
2839 * nilfs_detach_log_writer - destroy log writer
2840 * @sb: super block instance
2841 *
2842 * This kills log writer daemon, frees the log writer object, and
2843 * destroys list of dirty files.
2844 */
2845void nilfs_detach_log_writer(struct super_block *sb)
2846{
2847	struct the_nilfs *nilfs = sb->s_fs_info;
2848	LIST_HEAD(garbage_list);
2849
2850	down_write(&nilfs->ns_segctor_sem);
2851	if (nilfs->ns_writer) {
2852		nilfs_segctor_destroy(nilfs->ns_writer);
2853		nilfs->ns_writer = NULL;
2854	}
2855	set_nilfs_purging(nilfs);
2856
2857	/* Force to free the list of dirty files */
2858	spin_lock(&nilfs->ns_inode_lock);
2859	if (!list_empty(&nilfs->ns_dirty_files)) {
2860		list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2861		nilfs_warn(sb,
2862			   "disposed unprocessed dirty file(s) when detaching log writer");
2863	}
2864	spin_unlock(&nilfs->ns_inode_lock);
2865	up_write(&nilfs->ns_segctor_sem);
2866
2867	nilfs_dispose_list(nilfs, &garbage_list, 1);
2868	clear_nilfs_purging(nilfs);
2869}
2870