nilfs2: move log writer onto nilfs object
[linux-2.6.git] / fs / nilfs2 / segment.c
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 */
55 enum {
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 */
66 enum {
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 */
86 struct 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  */
104 static void nilfs_segctor_start_timer(struct nilfs_sc_info *);
105 static void nilfs_segctor_do_flush(struct nilfs_sc_info *, int);
106 static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *);
107 static 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
118 static 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  */
180 int nilfs_transaction_begin(struct super_block *sb,
181                             struct nilfs_transaction_info *ti,
182                             int vacancy_check)
183 {
184         struct nilfs_sb_info *sbi;
185         struct the_nilfs *nilfs;
186         int ret = nilfs_prepare_segment_lock(ti);
187
188         if (unlikely(ret < 0))
189                 return ret;
190         if (ret > 0)
191                 return 0;
192
193         vfs_check_frozen(sb, SB_FREEZE_WRITE);
194
195         sbi = NILFS_SB(sb);
196         nilfs = sbi->s_nilfs;
197         down_read(&nilfs->ns_segctor_sem);
198         if (vacancy_check && nilfs_near_disk_full(nilfs)) {
199                 up_read(&nilfs->ns_segctor_sem);
200                 ret = -ENOSPC;
201                 goto failed;
202         }
203         return 0;
204
205  failed:
206         ti = current->journal_info;
207         current->journal_info = ti->ti_save;
208         if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
209                 kmem_cache_free(nilfs_transaction_cachep, ti);
210         return ret;
211 }
212
213 /**
214  * nilfs_transaction_commit - commit indivisible file operations.
215  * @sb: super block
216  *
217  * nilfs_transaction_commit() releases the read semaphore which is
218  * acquired by nilfs_transaction_begin(). This is only performed
219  * in outermost call of this function.  If a commit flag is set,
220  * nilfs_transaction_commit() sets a timer to start the segment
221  * constructor.  If a sync flag is set, it starts construction
222  * directly.
223  */
224 int nilfs_transaction_commit(struct super_block *sb)
225 {
226         struct nilfs_transaction_info *ti = current->journal_info;
227         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
228         int err = 0;
229
230         BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
231         ti->ti_flags |= NILFS_TI_COMMIT;
232         if (ti->ti_count > 0) {
233                 ti->ti_count--;
234                 return 0;
235         }
236         if (nilfs->ns_writer) {
237                 struct nilfs_sc_info *sci = nilfs->ns_writer;
238
239                 if (ti->ti_flags & NILFS_TI_COMMIT)
240                         nilfs_segctor_start_timer(sci);
241                 if (atomic_read(&nilfs->ns_ndirtyblks) > sci->sc_watermark)
242                         nilfs_segctor_do_flush(sci, 0);
243         }
244         up_read(&nilfs->ns_segctor_sem);
245         current->journal_info = ti->ti_save;
246
247         if (ti->ti_flags & NILFS_TI_SYNC)
248                 err = nilfs_construct_segment(sb);
249         if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
250                 kmem_cache_free(nilfs_transaction_cachep, ti);
251         return err;
252 }
253
254 void nilfs_transaction_abort(struct super_block *sb)
255 {
256         struct nilfs_transaction_info *ti = current->journal_info;
257
258         BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
259         if (ti->ti_count > 0) {
260                 ti->ti_count--;
261                 return;
262         }
263         up_read(&NILFS_SB(sb)->s_nilfs->ns_segctor_sem);
264
265         current->journal_info = ti->ti_save;
266         if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
267                 kmem_cache_free(nilfs_transaction_cachep, ti);
268 }
269
270 void nilfs_relax_pressure_in_lock(struct super_block *sb)
271 {
272         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
273         struct nilfs_sc_info *sci = nilfs->ns_writer;
274
275         if (!sci || !sci->sc_flush_request)
276                 return;
277
278         set_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
279         up_read(&nilfs->ns_segctor_sem);
280
281         down_write(&nilfs->ns_segctor_sem);
282         if (sci->sc_flush_request &&
283             test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags)) {
284                 struct nilfs_transaction_info *ti = current->journal_info;
285
286                 ti->ti_flags |= NILFS_TI_WRITER;
287                 nilfs_segctor_do_immediate_flush(sci);
288                 ti->ti_flags &= ~NILFS_TI_WRITER;
289         }
290         downgrade_write(&nilfs->ns_segctor_sem);
291 }
292
293 static void nilfs_transaction_lock(struct nilfs_sb_info *sbi,
294                                    struct nilfs_transaction_info *ti,
295                                    int gcflag)
296 {
297         struct nilfs_transaction_info *cur_ti = current->journal_info;
298         struct the_nilfs *nilfs = sbi->s_nilfs;
299         struct nilfs_sc_info *sci = nilfs->ns_writer;
300
301         WARN_ON(cur_ti);
302         ti->ti_flags = NILFS_TI_WRITER;
303         ti->ti_count = 0;
304         ti->ti_save = cur_ti;
305         ti->ti_magic = NILFS_TI_MAGIC;
306         INIT_LIST_HEAD(&ti->ti_garbage);
307         current->journal_info = ti;
308
309         for (;;) {
310                 down_write(&nilfs->ns_segctor_sem);
311                 if (!test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags))
312                         break;
313
314                 nilfs_segctor_do_immediate_flush(sci);
315
316                 up_write(&sbi->s_nilfs->ns_segctor_sem);
317                 yield();
318         }
319         if (gcflag)
320                 ti->ti_flags |= NILFS_TI_GC;
321 }
322
323 static void nilfs_transaction_unlock(struct nilfs_sb_info *sbi)
324 {
325         struct nilfs_transaction_info *ti = current->journal_info;
326         struct the_nilfs *nilfs = sbi->s_nilfs;
327
328         BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
329         BUG_ON(ti->ti_count > 0);
330
331         up_write(&nilfs->ns_segctor_sem);
332         current->journal_info = ti->ti_save;
333         if (!list_empty(&ti->ti_garbage))
334                 nilfs_dispose_list(nilfs, &ti->ti_garbage, 0);
335 }
336
337 static void *nilfs_segctor_map_segsum_entry(struct nilfs_sc_info *sci,
338                                             struct nilfs_segsum_pointer *ssp,
339                                             unsigned bytes)
340 {
341         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
342         unsigned blocksize = sci->sc_super->s_blocksize;
343         void *p;
344
345         if (unlikely(ssp->offset + bytes > blocksize)) {
346                 ssp->offset = 0;
347                 BUG_ON(NILFS_SEGBUF_BH_IS_LAST(ssp->bh,
348                                                &segbuf->sb_segsum_buffers));
349                 ssp->bh = NILFS_SEGBUF_NEXT_BH(ssp->bh);
350         }
351         p = ssp->bh->b_data + ssp->offset;
352         ssp->offset += bytes;
353         return p;
354 }
355
356 /**
357  * nilfs_segctor_reset_segment_buffer - reset the current segment buffer
358  * @sci: nilfs_sc_info
359  */
360 static int nilfs_segctor_reset_segment_buffer(struct nilfs_sc_info *sci)
361 {
362         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
363         struct buffer_head *sumbh;
364         unsigned sumbytes;
365         unsigned flags = 0;
366         int err;
367
368         if (nilfs_doing_gc())
369                 flags = NILFS_SS_GC;
370         err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime, sci->sc_cno);
371         if (unlikely(err))
372                 return err;
373
374         sumbh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
375         sumbytes = segbuf->sb_sum.sumbytes;
376         sci->sc_finfo_ptr.bh = sumbh;  sci->sc_finfo_ptr.offset = sumbytes;
377         sci->sc_binfo_ptr.bh = sumbh;  sci->sc_binfo_ptr.offset = sumbytes;
378         sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
379         return 0;
380 }
381
382 static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
383 {
384         sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
385         if (NILFS_SEGBUF_IS_LAST(sci->sc_curseg, &sci->sc_segbufs))
386                 return -E2BIG; /* The current segment is filled up
387                                   (internal code) */
388         sci->sc_curseg = NILFS_NEXT_SEGBUF(sci->sc_curseg);
389         return nilfs_segctor_reset_segment_buffer(sci);
390 }
391
392 static int nilfs_segctor_add_super_root(struct nilfs_sc_info *sci)
393 {
394         struct nilfs_segment_buffer *segbuf = sci->sc_curseg;
395         int err;
396
397         if (segbuf->sb_sum.nblocks >= segbuf->sb_rest_blocks) {
398                 err = nilfs_segctor_feed_segment(sci);
399                 if (err)
400                         return err;
401                 segbuf = sci->sc_curseg;
402         }
403         err = nilfs_segbuf_extend_payload(segbuf, &segbuf->sb_super_root);
404         if (likely(!err))
405                 segbuf->sb_sum.flags |= NILFS_SS_SR;
406         return err;
407 }
408
409 /*
410  * Functions for making segment summary and payloads
411  */
412 static int nilfs_segctor_segsum_block_required(
413         struct nilfs_sc_info *sci, const struct nilfs_segsum_pointer *ssp,
414         unsigned binfo_size)
415 {
416         unsigned blocksize = sci->sc_super->s_blocksize;
417         /* Size of finfo and binfo is enough small against blocksize */
418
419         return ssp->offset + binfo_size +
420                 (!sci->sc_blk_cnt ? sizeof(struct nilfs_finfo) : 0) >
421                 blocksize;
422 }
423
424 static void nilfs_segctor_begin_finfo(struct nilfs_sc_info *sci,
425                                       struct inode *inode)
426 {
427         sci->sc_curseg->sb_sum.nfinfo++;
428         sci->sc_binfo_ptr = sci->sc_finfo_ptr;
429         nilfs_segctor_map_segsum_entry(
430                 sci, &sci->sc_binfo_ptr, sizeof(struct nilfs_finfo));
431
432         if (NILFS_I(inode)->i_root &&
433             !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
434                 set_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
435         /* skip finfo */
436 }
437
438 static void nilfs_segctor_end_finfo(struct nilfs_sc_info *sci,
439                                     struct inode *inode)
440 {
441         struct nilfs_finfo *finfo;
442         struct nilfs_inode_info *ii;
443         struct nilfs_segment_buffer *segbuf;
444         __u64 cno;
445
446         if (sci->sc_blk_cnt == 0)
447                 return;
448
449         ii = NILFS_I(inode);
450
451         if (test_bit(NILFS_I_GCINODE, &ii->i_state))
452                 cno = ii->i_cno;
453         else if (NILFS_ROOT_METADATA_FILE(inode->i_ino))
454                 cno = 0;
455         else
456                 cno = sci->sc_cno;
457
458         finfo = nilfs_segctor_map_segsum_entry(sci, &sci->sc_finfo_ptr,
459                                                  sizeof(*finfo));
460         finfo->fi_ino = cpu_to_le64(inode->i_ino);
461         finfo->fi_nblocks = cpu_to_le32(sci->sc_blk_cnt);
462         finfo->fi_ndatablk = cpu_to_le32(sci->sc_datablk_cnt);
463         finfo->fi_cno = cpu_to_le64(cno);
464
465         segbuf = sci->sc_curseg;
466         segbuf->sb_sum.sumbytes = sci->sc_binfo_ptr.offset +
467                 sci->sc_super->s_blocksize * (segbuf->sb_sum.nsumblk - 1);
468         sci->sc_finfo_ptr = sci->sc_binfo_ptr;
469         sci->sc_blk_cnt = sci->sc_datablk_cnt = 0;
470 }
471
472 static int nilfs_segctor_add_file_block(struct nilfs_sc_info *sci,
473                                         struct buffer_head *bh,
474                                         struct inode *inode,
475                                         unsigned binfo_size)
476 {
477         struct nilfs_segment_buffer *segbuf;
478         int required, err = 0;
479
480  retry:
481         segbuf = sci->sc_curseg;
482         required = nilfs_segctor_segsum_block_required(
483                 sci, &sci->sc_binfo_ptr, binfo_size);
484         if (segbuf->sb_sum.nblocks + required + 1 > segbuf->sb_rest_blocks) {
485                 nilfs_segctor_end_finfo(sci, inode);
486                 err = nilfs_segctor_feed_segment(sci);
487                 if (err)
488                         return err;
489                 goto retry;
490         }
491         if (unlikely(required)) {
492                 err = nilfs_segbuf_extend_segsum(segbuf);
493                 if (unlikely(err))
494                         goto failed;
495         }
496         if (sci->sc_blk_cnt == 0)
497                 nilfs_segctor_begin_finfo(sci, inode);
498
499         nilfs_segctor_map_segsum_entry(sci, &sci->sc_binfo_ptr, binfo_size);
500         /* Substitution to vblocknr is delayed until update_blocknr() */
501         nilfs_segbuf_add_file_buffer(segbuf, bh);
502         sci->sc_blk_cnt++;
503  failed:
504         return err;
505 }
506
507 /*
508  * Callback functions that enumerate, mark, and collect dirty blocks
509  */
510 static int nilfs_collect_file_data(struct nilfs_sc_info *sci,
511                                    struct buffer_head *bh, struct inode *inode)
512 {
513         int err;
514
515         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
516         if (err < 0)
517                 return err;
518
519         err = nilfs_segctor_add_file_block(sci, bh, inode,
520                                            sizeof(struct nilfs_binfo_v));
521         if (!err)
522                 sci->sc_datablk_cnt++;
523         return err;
524 }
525
526 static int nilfs_collect_file_node(struct nilfs_sc_info *sci,
527                                    struct buffer_head *bh,
528                                    struct inode *inode)
529 {
530         return nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
531 }
532
533 static int nilfs_collect_file_bmap(struct nilfs_sc_info *sci,
534                                    struct buffer_head *bh,
535                                    struct inode *inode)
536 {
537         WARN_ON(!buffer_dirty(bh));
538         return nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
539 }
540
541 static void nilfs_write_file_data_binfo(struct nilfs_sc_info *sci,
542                                         struct nilfs_segsum_pointer *ssp,
543                                         union nilfs_binfo *binfo)
544 {
545         struct nilfs_binfo_v *binfo_v = nilfs_segctor_map_segsum_entry(
546                 sci, ssp, sizeof(*binfo_v));
547         *binfo_v = binfo->bi_v;
548 }
549
550 static void nilfs_write_file_node_binfo(struct nilfs_sc_info *sci,
551                                         struct nilfs_segsum_pointer *ssp,
552                                         union nilfs_binfo *binfo)
553 {
554         __le64 *vblocknr = nilfs_segctor_map_segsum_entry(
555                 sci, ssp, sizeof(*vblocknr));
556         *vblocknr = binfo->bi_v.bi_vblocknr;
557 }
558
559 static struct nilfs_sc_operations nilfs_sc_file_ops = {
560         .collect_data = nilfs_collect_file_data,
561         .collect_node = nilfs_collect_file_node,
562         .collect_bmap = nilfs_collect_file_bmap,
563         .write_data_binfo = nilfs_write_file_data_binfo,
564         .write_node_binfo = nilfs_write_file_node_binfo,
565 };
566
567 static int nilfs_collect_dat_data(struct nilfs_sc_info *sci,
568                                   struct buffer_head *bh, struct inode *inode)
569 {
570         int err;
571
572         err = nilfs_bmap_propagate(NILFS_I(inode)->i_bmap, bh);
573         if (err < 0)
574                 return err;
575
576         err = nilfs_segctor_add_file_block(sci, bh, inode, sizeof(__le64));
577         if (!err)
578                 sci->sc_datablk_cnt++;
579         return err;
580 }
581
582 static int nilfs_collect_dat_bmap(struct nilfs_sc_info *sci,
583                                   struct buffer_head *bh, struct inode *inode)
584 {
585         WARN_ON(!buffer_dirty(bh));
586         return nilfs_segctor_add_file_block(sci, bh, inode,
587                                             sizeof(struct nilfs_binfo_dat));
588 }
589
590 static void nilfs_write_dat_data_binfo(struct nilfs_sc_info *sci,
591                                        struct nilfs_segsum_pointer *ssp,
592                                        union nilfs_binfo *binfo)
593 {
594         __le64 *blkoff = nilfs_segctor_map_segsum_entry(sci, ssp,
595                                                           sizeof(*blkoff));
596         *blkoff = binfo->bi_dat.bi_blkoff;
597 }
598
599 static void nilfs_write_dat_node_binfo(struct nilfs_sc_info *sci,
600                                        struct nilfs_segsum_pointer *ssp,
601                                        union nilfs_binfo *binfo)
602 {
603         struct nilfs_binfo_dat *binfo_dat =
604                 nilfs_segctor_map_segsum_entry(sci, ssp, sizeof(*binfo_dat));
605         *binfo_dat = binfo->bi_dat;
606 }
607
608 static struct nilfs_sc_operations nilfs_sc_dat_ops = {
609         .collect_data = nilfs_collect_dat_data,
610         .collect_node = nilfs_collect_file_node,
611         .collect_bmap = nilfs_collect_dat_bmap,
612         .write_data_binfo = nilfs_write_dat_data_binfo,
613         .write_node_binfo = nilfs_write_dat_node_binfo,
614 };
615
616 static struct nilfs_sc_operations nilfs_sc_dsync_ops = {
617         .collect_data = nilfs_collect_file_data,
618         .collect_node = NULL,
619         .collect_bmap = NULL,
620         .write_data_binfo = nilfs_write_file_data_binfo,
621         .write_node_binfo = NULL,
622 };
623
624 static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode,
625                                               struct list_head *listp,
626                                               size_t nlimit,
627                                               loff_t start, loff_t end)
628 {
629         struct address_space *mapping = inode->i_mapping;
630         struct pagevec pvec;
631         pgoff_t index = 0, last = ULONG_MAX;
632         size_t ndirties = 0;
633         int i;
634
635         if (unlikely(start != 0 || end != LLONG_MAX)) {
636                 /*
637                  * A valid range is given for sync-ing data pages. The
638                  * range is rounded to per-page; extra dirty buffers
639                  * may be included if blocksize < pagesize.
640                  */
641                 index = start >> PAGE_SHIFT;
642                 last = end >> PAGE_SHIFT;
643         }
644         pagevec_init(&pvec, 0);
645  repeat:
646         if (unlikely(index > last) ||
647             !pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
648                                 min_t(pgoff_t, last - index,
649                                       PAGEVEC_SIZE - 1) + 1))
650                 return ndirties;
651
652         for (i = 0; i < pagevec_count(&pvec); i++) {
653                 struct buffer_head *bh, *head;
654                 struct page *page = pvec.pages[i];
655
656                 if (unlikely(page->index > last))
657                         break;
658
659                 if (mapping->host) {
660                         lock_page(page);
661                         if (!page_has_buffers(page))
662                                 create_empty_buffers(page,
663                                                      1 << inode->i_blkbits, 0);
664                         unlock_page(page);
665                 }
666
667                 bh = head = page_buffers(page);
668                 do {
669                         if (!buffer_dirty(bh))
670                                 continue;
671                         get_bh(bh);
672                         list_add_tail(&bh->b_assoc_buffers, listp);
673                         ndirties++;
674                         if (unlikely(ndirties >= nlimit)) {
675                                 pagevec_release(&pvec);
676                                 cond_resched();
677                                 return ndirties;
678                         }
679                 } while (bh = bh->b_this_page, bh != head);
680         }
681         pagevec_release(&pvec);
682         cond_resched();
683         goto repeat;
684 }
685
686 static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
687                                             struct list_head *listp)
688 {
689         struct nilfs_inode_info *ii = NILFS_I(inode);
690         struct address_space *mapping = &ii->i_btnode_cache;
691         struct pagevec pvec;
692         struct buffer_head *bh, *head;
693         unsigned int i;
694         pgoff_t index = 0;
695
696         pagevec_init(&pvec, 0);
697
698         while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
699                                   PAGEVEC_SIZE)) {
700                 for (i = 0; i < pagevec_count(&pvec); i++) {
701                         bh = head = page_buffers(pvec.pages[i]);
702                         do {
703                                 if (buffer_dirty(bh)) {
704                                         get_bh(bh);
705                                         list_add_tail(&bh->b_assoc_buffers,
706                                                       listp);
707                                 }
708                                 bh = bh->b_this_page;
709                         } while (bh != head);
710                 }
711                 pagevec_release(&pvec);
712                 cond_resched();
713         }
714 }
715
716 static void nilfs_dispose_list(struct the_nilfs *nilfs,
717                                struct list_head *head, int force)
718 {
719         struct nilfs_inode_info *ii, *n;
720         struct nilfs_inode_info *ivec[SC_N_INODEVEC], **pii;
721         unsigned nv = 0;
722
723         while (!list_empty(head)) {
724                 spin_lock(&nilfs->ns_inode_lock);
725                 list_for_each_entry_safe(ii, n, head, i_dirty) {
726                         list_del_init(&ii->i_dirty);
727                         if (force) {
728                                 if (unlikely(ii->i_bh)) {
729                                         brelse(ii->i_bh);
730                                         ii->i_bh = NULL;
731                                 }
732                         } else if (test_bit(NILFS_I_DIRTY, &ii->i_state)) {
733                                 set_bit(NILFS_I_QUEUED, &ii->i_state);
734                                 list_add_tail(&ii->i_dirty,
735                                               &nilfs->ns_dirty_files);
736                                 continue;
737                         }
738                         ivec[nv++] = ii;
739                         if (nv == SC_N_INODEVEC)
740                                 break;
741                 }
742                 spin_unlock(&nilfs->ns_inode_lock);
743
744                 for (pii = ivec; nv > 0; pii++, nv--)
745                         iput(&(*pii)->vfs_inode);
746         }
747 }
748
749 static int nilfs_test_metadata_dirty(struct the_nilfs *nilfs,
750                                      struct nilfs_root *root)
751 {
752         int ret = 0;
753
754         if (nilfs_mdt_fetch_dirty(root->ifile))
755                 ret++;
756         if (nilfs_mdt_fetch_dirty(nilfs->ns_cpfile))
757                 ret++;
758         if (nilfs_mdt_fetch_dirty(nilfs->ns_sufile))
759                 ret++;
760         if ((ret || nilfs_doing_gc()) && nilfs_mdt_fetch_dirty(nilfs->ns_dat))
761                 ret++;
762         return ret;
763 }
764
765 static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
766 {
767         return list_empty(&sci->sc_dirty_files) &&
768                 !test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
769                 sci->sc_nfreesegs == 0 &&
770                 (!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
771 }
772
773 static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
774 {
775         struct the_nilfs *nilfs = sci->sc_sbi->s_nilfs;
776         int ret = 0;
777
778         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
779                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
780
781         spin_lock(&nilfs->ns_inode_lock);
782         if (list_empty(&nilfs->ns_dirty_files) && nilfs_segctor_clean(sci))
783                 ret++;
784
785         spin_unlock(&nilfs->ns_inode_lock);
786         return ret;
787 }
788
789 static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
790 {
791         struct nilfs_sb_info *sbi = sci->sc_sbi;
792         struct the_nilfs *nilfs = sbi->s_nilfs;
793
794         nilfs_mdt_clear_dirty(sci->sc_root->ifile);
795         nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
796         nilfs_mdt_clear_dirty(nilfs->ns_sufile);
797         nilfs_mdt_clear_dirty(nilfs->ns_dat);
798 }
799
800 static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
801 {
802         struct the_nilfs *nilfs = sci->sc_sbi->s_nilfs;
803         struct buffer_head *bh_cp;
804         struct nilfs_checkpoint *raw_cp;
805         int err;
806
807         /* XXX: this interface will be changed */
808         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 1,
809                                           &raw_cp, &bh_cp);
810         if (likely(!err)) {
811                 /* The following code is duplicated with cpfile.  But, it is
812                    needed to collect the checkpoint even if it was not newly
813                    created */
814                 nilfs_mdt_mark_buffer_dirty(bh_cp);
815                 nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
816                 nilfs_cpfile_put_checkpoint(
817                         nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
818         } else
819                 WARN_ON(err == -EINVAL || err == -ENOENT);
820
821         return err;
822 }
823
824 static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
825 {
826         struct nilfs_sb_info *sbi = sci->sc_sbi;
827         struct the_nilfs *nilfs = sbi->s_nilfs;
828         struct buffer_head *bh_cp;
829         struct nilfs_checkpoint *raw_cp;
830         int err;
831
832         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
833                                           &raw_cp, &bh_cp);
834         if (unlikely(err)) {
835                 WARN_ON(err == -EINVAL || err == -ENOENT);
836                 goto failed_ibh;
837         }
838         raw_cp->cp_snapshot_list.ssl_next = 0;
839         raw_cp->cp_snapshot_list.ssl_prev = 0;
840         raw_cp->cp_inodes_count =
841                 cpu_to_le64(atomic_read(&sci->sc_root->inodes_count));
842         raw_cp->cp_blocks_count =
843                 cpu_to_le64(atomic_read(&sci->sc_root->blocks_count));
844         raw_cp->cp_nblk_inc =
845                 cpu_to_le64(sci->sc_nblk_inc + sci->sc_nblk_this_inc);
846         raw_cp->cp_create = cpu_to_le64(sci->sc_seg_ctime);
847         raw_cp->cp_cno = cpu_to_le64(nilfs->ns_cno);
848
849         if (test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
850                 nilfs_checkpoint_clear_minor(raw_cp);
851         else
852                 nilfs_checkpoint_set_minor(raw_cp);
853
854         nilfs_write_inode_common(sci->sc_root->ifile,
855                                  &raw_cp->cp_ifile_inode, 1);
856         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
857         return 0;
858
859  failed_ibh:
860         return err;
861 }
862
863 static void nilfs_fill_in_file_bmap(struct inode *ifile,
864                                     struct nilfs_inode_info *ii)
865
866 {
867         struct buffer_head *ibh;
868         struct nilfs_inode *raw_inode;
869
870         if (test_bit(NILFS_I_BMAP, &ii->i_state)) {
871                 ibh = ii->i_bh;
872                 BUG_ON(!ibh);
873                 raw_inode = nilfs_ifile_map_inode(ifile, ii->vfs_inode.i_ino,
874                                                   ibh);
875                 nilfs_bmap_write(ii->i_bmap, raw_inode);
876                 nilfs_ifile_unmap_inode(ifile, ii->vfs_inode.i_ino, ibh);
877         }
878 }
879
880 static void nilfs_segctor_fill_in_file_bmap(struct nilfs_sc_info *sci)
881 {
882         struct nilfs_inode_info *ii;
883
884         list_for_each_entry(ii, &sci->sc_dirty_files, i_dirty) {
885                 nilfs_fill_in_file_bmap(sci->sc_root->ifile, ii);
886                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
887         }
888 }
889
890 static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
891                                              struct the_nilfs *nilfs)
892 {
893         struct buffer_head *bh_sr;
894         struct nilfs_super_root *raw_sr;
895         unsigned isz = nilfs->ns_inode_size;
896
897         bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
898         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
899
900         raw_sr->sr_bytes = cpu_to_le16(NILFS_SR_BYTES);
901         raw_sr->sr_nongc_ctime
902                 = cpu_to_le64(nilfs_doing_gc() ?
903                               nilfs->ns_nongc_ctime : sci->sc_seg_ctime);
904         raw_sr->sr_flags = 0;
905
906         nilfs_write_inode_common(nilfs->ns_dat, (void *)raw_sr +
907                                  NILFS_SR_DAT_OFFSET(isz), 1);
908         nilfs_write_inode_common(nilfs->ns_cpfile, (void *)raw_sr +
909                                  NILFS_SR_CPFILE_OFFSET(isz), 1);
910         nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
911                                  NILFS_SR_SUFILE_OFFSET(isz), 1);
912 }
913
914 static void nilfs_redirty_inodes(struct list_head *head)
915 {
916         struct nilfs_inode_info *ii;
917
918         list_for_each_entry(ii, head, i_dirty) {
919                 if (test_bit(NILFS_I_COLLECTED, &ii->i_state))
920                         clear_bit(NILFS_I_COLLECTED, &ii->i_state);
921         }
922 }
923
924 static void nilfs_drop_collected_inodes(struct list_head *head)
925 {
926         struct nilfs_inode_info *ii;
927
928         list_for_each_entry(ii, head, i_dirty) {
929                 if (!test_and_clear_bit(NILFS_I_COLLECTED, &ii->i_state))
930                         continue;
931
932                 clear_bit(NILFS_I_INODE_DIRTY, &ii->i_state);
933                 set_bit(NILFS_I_UPDATED, &ii->i_state);
934         }
935 }
936
937 static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
938                                        struct inode *inode,
939                                        struct list_head *listp,
940                                        int (*collect)(struct nilfs_sc_info *,
941                                                       struct buffer_head *,
942                                                       struct inode *))
943 {
944         struct buffer_head *bh, *n;
945         int err = 0;
946
947         if (collect) {
948                 list_for_each_entry_safe(bh, n, listp, b_assoc_buffers) {
949                         list_del_init(&bh->b_assoc_buffers);
950                         err = collect(sci, bh, inode);
951                         brelse(bh);
952                         if (unlikely(err))
953                                 goto dispose_buffers;
954                 }
955                 return 0;
956         }
957
958  dispose_buffers:
959         while (!list_empty(listp)) {
960                 bh = list_entry(listp->next, struct buffer_head,
961                                 b_assoc_buffers);
962                 list_del_init(&bh->b_assoc_buffers);
963                 brelse(bh);
964         }
965         return err;
966 }
967
968 static size_t nilfs_segctor_buffer_rest(struct nilfs_sc_info *sci)
969 {
970         /* Remaining number of blocks within segment buffer */
971         return sci->sc_segbuf_nblocks -
972                 (sci->sc_nblk_this_inc + sci->sc_curseg->sb_sum.nblocks);
973 }
974
975 static int nilfs_segctor_scan_file(struct nilfs_sc_info *sci,
976                                    struct inode *inode,
977                                    struct nilfs_sc_operations *sc_ops)
978 {
979         LIST_HEAD(data_buffers);
980         LIST_HEAD(node_buffers);
981         int err;
982
983         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
984                 size_t n, rest = nilfs_segctor_buffer_rest(sci);
985
986                 n = nilfs_lookup_dirty_data_buffers(
987                         inode, &data_buffers, rest + 1, 0, LLONG_MAX);
988                 if (n > rest) {
989                         err = nilfs_segctor_apply_buffers(
990                                 sci, inode, &data_buffers,
991                                 sc_ops->collect_data);
992                         BUG_ON(!err); /* always receive -E2BIG or true error */
993                         goto break_or_fail;
994                 }
995         }
996         nilfs_lookup_dirty_node_buffers(inode, &node_buffers);
997
998         if (!(sci->sc_stage.flags & NILFS_CF_NODE)) {
999                 err = nilfs_segctor_apply_buffers(
1000                         sci, inode, &data_buffers, sc_ops->collect_data);
1001                 if (unlikely(err)) {
1002                         /* dispose node list */
1003                         nilfs_segctor_apply_buffers(
1004                                 sci, inode, &node_buffers, NULL);
1005                         goto break_or_fail;
1006                 }
1007                 sci->sc_stage.flags |= NILFS_CF_NODE;
1008         }
1009         /* Collect node */
1010         err = nilfs_segctor_apply_buffers(
1011                 sci, inode, &node_buffers, sc_ops->collect_node);
1012         if (unlikely(err))
1013                 goto break_or_fail;
1014
1015         nilfs_bmap_lookup_dirty_buffers(NILFS_I(inode)->i_bmap, &node_buffers);
1016         err = nilfs_segctor_apply_buffers(
1017                 sci, inode, &node_buffers, sc_ops->collect_bmap);
1018         if (unlikely(err))
1019                 goto break_or_fail;
1020
1021         nilfs_segctor_end_finfo(sci, inode);
1022         sci->sc_stage.flags &= ~NILFS_CF_NODE;
1023
1024  break_or_fail:
1025         return err;
1026 }
1027
1028 static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
1029                                          struct inode *inode)
1030 {
1031         LIST_HEAD(data_buffers);
1032         size_t n, rest = nilfs_segctor_buffer_rest(sci);
1033         int err;
1034
1035         n = nilfs_lookup_dirty_data_buffers(inode, &data_buffers, rest + 1,
1036                                             sci->sc_dsync_start,
1037                                             sci->sc_dsync_end);
1038
1039         err = nilfs_segctor_apply_buffers(sci, inode, &data_buffers,
1040                                           nilfs_collect_file_data);
1041         if (!err) {
1042                 nilfs_segctor_end_finfo(sci, inode);
1043                 BUG_ON(n > rest);
1044                 /* always receive -E2BIG or true error if n > rest */
1045         }
1046         return err;
1047 }
1048
1049 static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
1050 {
1051         struct nilfs_sb_info *sbi = sci->sc_sbi;
1052         struct the_nilfs *nilfs = sbi->s_nilfs;
1053         struct list_head *head;
1054         struct nilfs_inode_info *ii;
1055         size_t ndone;
1056         int err = 0;
1057
1058         switch (sci->sc_stage.scnt) {
1059         case NILFS_ST_INIT:
1060                 /* Pre-processes */
1061                 sci->sc_stage.flags = 0;
1062
1063                 if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags)) {
1064                         sci->sc_nblk_inc = 0;
1065                         sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
1066                         if (mode == SC_LSEG_DSYNC) {
1067                                 sci->sc_stage.scnt = NILFS_ST_DSYNC;
1068                                 goto dsync_mode;
1069                         }
1070                 }
1071
1072                 sci->sc_stage.dirty_file_ptr = NULL;
1073                 sci->sc_stage.gc_inode_ptr = NULL;
1074                 if (mode == SC_FLUSH_DAT) {
1075                         sci->sc_stage.scnt = NILFS_ST_DAT;
1076                         goto dat_stage;
1077                 }
1078                 sci->sc_stage.scnt++;  /* Fall through */
1079         case NILFS_ST_GC:
1080                 if (nilfs_doing_gc()) {
1081                         head = &sci->sc_gc_inodes;
1082                         ii = list_prepare_entry(sci->sc_stage.gc_inode_ptr,
1083                                                 head, i_dirty);
1084                         list_for_each_entry_continue(ii, head, i_dirty) {
1085                                 err = nilfs_segctor_scan_file(
1086                                         sci, &ii->vfs_inode,
1087                                         &nilfs_sc_file_ops);
1088                                 if (unlikely(err)) {
1089                                         sci->sc_stage.gc_inode_ptr = list_entry(
1090                                                 ii->i_dirty.prev,
1091                                                 struct nilfs_inode_info,
1092                                                 i_dirty);
1093                                         goto break_or_fail;
1094                                 }
1095                                 set_bit(NILFS_I_COLLECTED, &ii->i_state);
1096                         }
1097                         sci->sc_stage.gc_inode_ptr = NULL;
1098                 }
1099                 sci->sc_stage.scnt++;  /* Fall through */
1100         case NILFS_ST_FILE:
1101                 head = &sci->sc_dirty_files;
1102                 ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
1103                                         i_dirty);
1104                 list_for_each_entry_continue(ii, head, i_dirty) {
1105                         clear_bit(NILFS_I_DIRTY, &ii->i_state);
1106
1107                         err = nilfs_segctor_scan_file(sci, &ii->vfs_inode,
1108                                                       &nilfs_sc_file_ops);
1109                         if (unlikely(err)) {
1110                                 sci->sc_stage.dirty_file_ptr =
1111                                         list_entry(ii->i_dirty.prev,
1112                                                    struct nilfs_inode_info,
1113                                                    i_dirty);
1114                                 goto break_or_fail;
1115                         }
1116                         /* sci->sc_stage.dirty_file_ptr = NILFS_I(inode); */
1117                         /* XXX: required ? */
1118                 }
1119                 sci->sc_stage.dirty_file_ptr = NULL;
1120                 if (mode == SC_FLUSH_FILE) {
1121                         sci->sc_stage.scnt = NILFS_ST_DONE;
1122                         return 0;
1123                 }
1124                 sci->sc_stage.scnt++;
1125                 sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
1126                 /* Fall through */
1127         case NILFS_ST_IFILE:
1128                 err = nilfs_segctor_scan_file(sci, sci->sc_root->ifile,
1129                                               &nilfs_sc_file_ops);
1130                 if (unlikely(err))
1131                         break;
1132                 sci->sc_stage.scnt++;
1133                 /* Creating a checkpoint */
1134                 err = nilfs_segctor_create_checkpoint(sci);
1135                 if (unlikely(err))
1136                         break;
1137                 /* Fall through */
1138         case NILFS_ST_CPFILE:
1139                 err = nilfs_segctor_scan_file(sci, nilfs->ns_cpfile,
1140                                               &nilfs_sc_file_ops);
1141                 if (unlikely(err))
1142                         break;
1143                 sci->sc_stage.scnt++;  /* Fall through */
1144         case NILFS_ST_SUFILE:
1145                 err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
1146                                          sci->sc_nfreesegs, &ndone);
1147                 if (unlikely(err)) {
1148                         nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1149                                                   sci->sc_freesegs, ndone,
1150                                                   NULL);
1151                         break;
1152                 }
1153                 sci->sc_stage.flags |= NILFS_CF_SUFREED;
1154
1155                 err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
1156                                               &nilfs_sc_file_ops);
1157                 if (unlikely(err))
1158                         break;
1159                 sci->sc_stage.scnt++;  /* Fall through */
1160         case NILFS_ST_DAT:
1161  dat_stage:
1162                 err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
1163                                               &nilfs_sc_dat_ops);
1164                 if (unlikely(err))
1165                         break;
1166                 if (mode == SC_FLUSH_DAT) {
1167                         sci->sc_stage.scnt = NILFS_ST_DONE;
1168                         return 0;
1169                 }
1170                 sci->sc_stage.scnt++;  /* Fall through */
1171         case NILFS_ST_SR:
1172                 if (mode == SC_LSEG_SR) {
1173                         /* Appending a super root */
1174                         err = nilfs_segctor_add_super_root(sci);
1175                         if (unlikely(err))
1176                                 break;
1177                 }
1178                 /* End of a logical segment */
1179                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1180                 sci->sc_stage.scnt = NILFS_ST_DONE;
1181                 return 0;
1182         case NILFS_ST_DSYNC:
1183  dsync_mode:
1184                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_SYNDT;
1185                 ii = sci->sc_dsync_inode;
1186                 if (!test_bit(NILFS_I_BUSY, &ii->i_state))
1187                         break;
1188
1189                 err = nilfs_segctor_scan_file_dsync(sci, &ii->vfs_inode);
1190                 if (unlikely(err))
1191                         break;
1192                 sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
1193                 sci->sc_stage.scnt = NILFS_ST_DONE;
1194                 return 0;
1195         case NILFS_ST_DONE:
1196                 return 0;
1197         default:
1198                 BUG();
1199         }
1200
1201  break_or_fail:
1202         return err;
1203 }
1204
1205 /**
1206  * nilfs_segctor_begin_construction - setup segment buffer to make a new log
1207  * @sci: nilfs_sc_info
1208  * @nilfs: nilfs object
1209  */
1210 static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
1211                                             struct the_nilfs *nilfs)
1212 {
1213         struct nilfs_segment_buffer *segbuf, *prev;
1214         __u64 nextnum;
1215         int err, alloc = 0;
1216
1217         segbuf = nilfs_segbuf_new(sci->sc_super);
1218         if (unlikely(!segbuf))
1219                 return -ENOMEM;
1220
1221         if (list_empty(&sci->sc_write_logs)) {
1222                 nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
1223                                  nilfs->ns_pseg_offset, nilfs);
1224                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1225                         nilfs_shift_to_next_segment(nilfs);
1226                         nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
1227                 }
1228
1229                 segbuf->sb_sum.seg_seq = nilfs->ns_seg_seq;
1230                 nextnum = nilfs->ns_nextnum;
1231
1232                 if (nilfs->ns_segnum == nilfs->ns_nextnum)
1233                         /* Start from the head of a new full segment */
1234                         alloc++;
1235         } else {
1236                 /* Continue logs */
1237                 prev = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1238                 nilfs_segbuf_map_cont(segbuf, prev);
1239                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq;
1240                 nextnum = prev->sb_nextnum;
1241
1242                 if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
1243                         nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1244                         segbuf->sb_sum.seg_seq++;
1245                         alloc++;
1246                 }
1247         }
1248
1249         err = nilfs_sufile_mark_dirty(nilfs->ns_sufile, segbuf->sb_segnum);
1250         if (err)
1251                 goto failed;
1252
1253         if (alloc) {
1254                 err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
1255                 if (err)
1256                         goto failed;
1257         }
1258         nilfs_segbuf_set_next_segnum(segbuf, nextnum, nilfs);
1259
1260         BUG_ON(!list_empty(&sci->sc_segbufs));
1261         list_add_tail(&segbuf->sb_list, &sci->sc_segbufs);
1262         sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
1263         return 0;
1264
1265  failed:
1266         nilfs_segbuf_free(segbuf);
1267         return err;
1268 }
1269
1270 static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
1271                                          struct the_nilfs *nilfs, int nadd)
1272 {
1273         struct nilfs_segment_buffer *segbuf, *prev;
1274         struct inode *sufile = nilfs->ns_sufile;
1275         __u64 nextnextnum;
1276         LIST_HEAD(list);
1277         int err, ret, i;
1278
1279         prev = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
1280         /*
1281          * Since the segment specified with nextnum might be allocated during
1282          * the previous construction, the buffer including its segusage may
1283          * not be dirty.  The following call ensures that the buffer is dirty
1284          * and will pin the buffer on memory until the sufile is written.
1285          */
1286         err = nilfs_sufile_mark_dirty(sufile, prev->sb_nextnum);
1287         if (unlikely(err))
1288                 return err;
1289
1290         for (i = 0; i < nadd; i++) {
1291                 /* extend segment info */
1292                 err = -ENOMEM;
1293                 segbuf = nilfs_segbuf_new(sci->sc_super);
1294                 if (unlikely(!segbuf))
1295                         goto failed;
1296
1297                 /* map this buffer to region of segment on-disk */
1298                 nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
1299                 sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
1300
1301                 /* allocate the next next full segment */
1302                 err = nilfs_sufile_alloc(sufile, &nextnextnum);
1303                 if (unlikely(err))
1304                         goto failed_segbuf;
1305
1306                 segbuf->sb_sum.seg_seq = prev->sb_sum.seg_seq + 1;
1307                 nilfs_segbuf_set_next_segnum(segbuf, nextnextnum, nilfs);
1308
1309                 list_add_tail(&segbuf->sb_list, &list);
1310                 prev = segbuf;
1311         }
1312         list_splice_tail(&list, &sci->sc_segbufs);
1313         return 0;
1314
1315  failed_segbuf:
1316         nilfs_segbuf_free(segbuf);
1317  failed:
1318         list_for_each_entry(segbuf, &list, sb_list) {
1319                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1320                 WARN_ON(ret); /* never fails */
1321         }
1322         nilfs_destroy_logs(&list);
1323         return err;
1324 }
1325
1326 static void nilfs_free_incomplete_logs(struct list_head *logs,
1327                                        struct the_nilfs *nilfs)
1328 {
1329         struct nilfs_segment_buffer *segbuf, *prev;
1330         struct inode *sufile = nilfs->ns_sufile;
1331         int ret;
1332
1333         segbuf = NILFS_FIRST_SEGBUF(logs);
1334         if (nilfs->ns_nextnum != segbuf->sb_nextnum) {
1335                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1336                 WARN_ON(ret); /* never fails */
1337         }
1338         if (atomic_read(&segbuf->sb_err)) {
1339                 /* Case 1: The first segment failed */
1340                 if (segbuf->sb_pseg_start != segbuf->sb_fseg_start)
1341                         /* Case 1a:  Partial segment appended into an existing
1342                            segment */
1343                         nilfs_terminate_segment(nilfs, segbuf->sb_fseg_start,
1344                                                 segbuf->sb_fseg_end);
1345                 else /* Case 1b:  New full segment */
1346                         set_nilfs_discontinued(nilfs);
1347         }
1348
1349         prev = segbuf;
1350         list_for_each_entry_continue(segbuf, logs, sb_list) {
1351                 if (prev->sb_nextnum != segbuf->sb_nextnum) {
1352                         ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1353                         WARN_ON(ret); /* never fails */
1354                 }
1355                 if (atomic_read(&segbuf->sb_err) &&
1356                     segbuf->sb_segnum != nilfs->ns_nextnum)
1357                         /* Case 2: extended segment (!= next) failed */
1358                         nilfs_sufile_set_error(sufile, segbuf->sb_segnum);
1359                 prev = segbuf;
1360         }
1361 }
1362
1363 static void nilfs_segctor_update_segusage(struct nilfs_sc_info *sci,
1364                                           struct inode *sufile)
1365 {
1366         struct nilfs_segment_buffer *segbuf;
1367         unsigned long live_blocks;
1368         int ret;
1369
1370         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1371                 live_blocks = segbuf->sb_sum.nblocks +
1372                         (segbuf->sb_pseg_start - segbuf->sb_fseg_start);
1373                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1374                                                      live_blocks,
1375                                                      sci->sc_seg_ctime);
1376                 WARN_ON(ret); /* always succeed because the segusage is dirty */
1377         }
1378 }
1379
1380 static void nilfs_cancel_segusage(struct list_head *logs, struct inode *sufile)
1381 {
1382         struct nilfs_segment_buffer *segbuf;
1383         int ret;
1384
1385         segbuf = NILFS_FIRST_SEGBUF(logs);
1386         ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1387                                              segbuf->sb_pseg_start -
1388                                              segbuf->sb_fseg_start, 0);
1389         WARN_ON(ret); /* always succeed because the segusage is dirty */
1390
1391         list_for_each_entry_continue(segbuf, logs, sb_list) {
1392                 ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
1393                                                      0, 0);
1394                 WARN_ON(ret); /* always succeed */
1395         }
1396 }
1397
1398 static void nilfs_segctor_truncate_segments(struct nilfs_sc_info *sci,
1399                                             struct nilfs_segment_buffer *last,
1400                                             struct inode *sufile)
1401 {
1402         struct nilfs_segment_buffer *segbuf = last;
1403         int ret;
1404
1405         list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
1406                 sci->sc_segbuf_nblocks -= segbuf->sb_rest_blocks;
1407                 ret = nilfs_sufile_free(sufile, segbuf->sb_nextnum);
1408                 WARN_ON(ret);
1409         }
1410         nilfs_truncate_logs(&sci->sc_segbufs, last);
1411 }
1412
1413
1414 static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
1415                                  struct the_nilfs *nilfs, int mode)
1416 {
1417         struct nilfs_cstage prev_stage = sci->sc_stage;
1418         int err, nadd = 1;
1419
1420         /* Collection retry loop */
1421         for (;;) {
1422                 sci->sc_nblk_this_inc = 0;
1423                 sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
1424
1425                 err = nilfs_segctor_reset_segment_buffer(sci);
1426                 if (unlikely(err))
1427                         goto failed;
1428
1429                 err = nilfs_segctor_collect_blocks(sci, mode);
1430                 sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
1431                 if (!err)
1432                         break;
1433
1434                 if (unlikely(err != -E2BIG))
1435                         goto failed;
1436
1437                 /* The current segment is filled up */
1438                 if (mode != SC_LSEG_SR || sci->sc_stage.scnt < NILFS_ST_CPFILE)
1439                         break;
1440
1441                 nilfs_clear_logs(&sci->sc_segbufs);
1442
1443                 err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
1444                 if (unlikely(err))
1445                         return err;
1446
1447                 if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1448                         err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1449                                                         sci->sc_freesegs,
1450                                                         sci->sc_nfreesegs,
1451                                                         NULL);
1452                         WARN_ON(err); /* do not happen */
1453                 }
1454                 nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
1455                 sci->sc_stage = prev_stage;
1456         }
1457         nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
1458         return 0;
1459
1460  failed:
1461         return err;
1462 }
1463
1464 static void nilfs_list_replace_buffer(struct buffer_head *old_bh,
1465                                       struct buffer_head *new_bh)
1466 {
1467         BUG_ON(!list_empty(&new_bh->b_assoc_buffers));
1468
1469         list_replace_init(&old_bh->b_assoc_buffers, &new_bh->b_assoc_buffers);
1470         /* The caller must release old_bh */
1471 }
1472
1473 static int
1474 nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
1475                                      struct nilfs_segment_buffer *segbuf,
1476                                      int mode)
1477 {
1478         struct inode *inode = NULL;
1479         sector_t blocknr;
1480         unsigned long nfinfo = segbuf->sb_sum.nfinfo;
1481         unsigned long nblocks = 0, ndatablk = 0;
1482         struct nilfs_sc_operations *sc_op = NULL;
1483         struct nilfs_segsum_pointer ssp;
1484         struct nilfs_finfo *finfo = NULL;
1485         union nilfs_binfo binfo;
1486         struct buffer_head *bh, *bh_org;
1487         ino_t ino = 0;
1488         int err = 0;
1489
1490         if (!nfinfo)
1491                 goto out;
1492
1493         blocknr = segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk;
1494         ssp.bh = NILFS_SEGBUF_FIRST_BH(&segbuf->sb_segsum_buffers);
1495         ssp.offset = sizeof(struct nilfs_segment_summary);
1496
1497         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
1498                 if (bh == segbuf->sb_super_root)
1499                         break;
1500                 if (!finfo) {
1501                         finfo = nilfs_segctor_map_segsum_entry(
1502                                 sci, &ssp, sizeof(*finfo));
1503                         ino = le64_to_cpu(finfo->fi_ino);
1504                         nblocks = le32_to_cpu(finfo->fi_nblocks);
1505                         ndatablk = le32_to_cpu(finfo->fi_ndatablk);
1506
1507                         if (buffer_nilfs_node(bh))
1508                                 inode = NILFS_BTNC_I(bh->b_page->mapping);
1509                         else
1510                                 inode = NILFS_AS_I(bh->b_page->mapping);
1511
1512                         if (mode == SC_LSEG_DSYNC)
1513                                 sc_op = &nilfs_sc_dsync_ops;
1514                         else if (ino == NILFS_DAT_INO)
1515                                 sc_op = &nilfs_sc_dat_ops;
1516                         else /* file blocks */
1517                                 sc_op = &nilfs_sc_file_ops;
1518                 }
1519                 bh_org = bh;
1520                 get_bh(bh_org);
1521                 err = nilfs_bmap_assign(NILFS_I(inode)->i_bmap, &bh, blocknr,
1522                                         &binfo);
1523                 if (bh != bh_org)
1524                         nilfs_list_replace_buffer(bh_org, bh);
1525                 brelse(bh_org);
1526                 if (unlikely(err))
1527                         goto failed_bmap;
1528
1529                 if (ndatablk > 0)
1530                         sc_op->write_data_binfo(sci, &ssp, &binfo);
1531                 else
1532                         sc_op->write_node_binfo(sci, &ssp, &binfo);
1533
1534                 blocknr++;
1535                 if (--nblocks == 0) {
1536                         finfo = NULL;
1537                         if (--nfinfo == 0)
1538                                 break;
1539                 } else if (ndatablk > 0)
1540                         ndatablk--;
1541         }
1542  out:
1543         return 0;
1544
1545  failed_bmap:
1546         return err;
1547 }
1548
1549 static int nilfs_segctor_assign(struct nilfs_sc_info *sci, int mode)
1550 {
1551         struct nilfs_segment_buffer *segbuf;
1552         int err;
1553
1554         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1555                 err = nilfs_segctor_update_payload_blocknr(sci, segbuf, mode);
1556                 if (unlikely(err))
1557                         return err;
1558                 nilfs_segbuf_fill_in_segsum(segbuf);
1559         }
1560         return 0;
1561 }
1562
1563 static int
1564 nilfs_copy_replace_page_buffers(struct page *page, struct list_head *out)
1565 {
1566         struct page *clone_page;
1567         struct buffer_head *bh, *head, *bh2;
1568         void *kaddr;
1569
1570         bh = head = page_buffers(page);
1571
1572         clone_page = nilfs_alloc_private_page(bh->b_bdev, bh->b_size, 0);
1573         if (unlikely(!clone_page))
1574                 return -ENOMEM;
1575
1576         bh2 = page_buffers(clone_page);
1577         kaddr = kmap_atomic(page, KM_USER0);
1578         do {
1579                 if (list_empty(&bh->b_assoc_buffers))
1580                         continue;
1581                 get_bh(bh2);
1582                 page_cache_get(clone_page); /* for each bh */
1583                 memcpy(bh2->b_data, kaddr + bh_offset(bh), bh2->b_size);
1584                 bh2->b_blocknr = bh->b_blocknr;
1585                 list_replace(&bh->b_assoc_buffers, &bh2->b_assoc_buffers);
1586                 list_add_tail(&bh->b_assoc_buffers, out);
1587         } while (bh = bh->b_this_page, bh2 = bh2->b_this_page, bh != head);
1588         kunmap_atomic(kaddr, KM_USER0);
1589
1590         if (!TestSetPageWriteback(clone_page))
1591                 account_page_writeback(clone_page);
1592         unlock_page(clone_page);
1593
1594         return 0;
1595 }
1596
1597 static int nilfs_test_page_to_be_frozen(struct page *page)
1598 {
1599         struct address_space *mapping = page->mapping;
1600
1601         if (!mapping || !mapping->host || S_ISDIR(mapping->host->i_mode))
1602                 return 0;
1603
1604         if (page_mapped(page)) {
1605                 ClearPageChecked(page);
1606                 return 1;
1607         }
1608         return PageChecked(page);
1609 }
1610
1611 static int nilfs_begin_page_io(struct page *page, struct list_head *out)
1612 {
1613         if (!page || PageWriteback(page))
1614                 /* For split b-tree node pages, this function may be called
1615                    twice.  We ignore the 2nd or later calls by this check. */
1616                 return 0;
1617
1618         lock_page(page);
1619         clear_page_dirty_for_io(page);
1620         set_page_writeback(page);
1621         unlock_page(page);
1622
1623         if (nilfs_test_page_to_be_frozen(page)) {
1624                 int err = nilfs_copy_replace_page_buffers(page, out);
1625                 if (unlikely(err))
1626                         return err;
1627         }
1628         return 0;
1629 }
1630
1631 static int nilfs_segctor_prepare_write(struct nilfs_sc_info *sci,
1632                                        struct page **failed_page)
1633 {
1634         struct nilfs_segment_buffer *segbuf;
1635         struct page *bd_page = NULL, *fs_page = NULL;
1636         struct list_head *list = &sci->sc_copied_buffers;
1637         int err;
1638
1639         *failed_page = NULL;
1640         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
1641                 struct buffer_head *bh;
1642
1643                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1644                                     b_assoc_buffers) {
1645                         if (bh->b_page != bd_page) {
1646                                 if (bd_page) {
1647                                         lock_page(bd_page);
1648                                         clear_page_dirty_for_io(bd_page);
1649                                         set_page_writeback(bd_page);
1650                                         unlock_page(bd_page);
1651                                 }
1652                                 bd_page = bh->b_page;
1653                         }
1654                 }
1655
1656                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1657                                     b_assoc_buffers) {
1658                         if (bh == segbuf->sb_super_root) {
1659                                 if (bh->b_page != bd_page) {
1660                                         lock_page(bd_page);
1661                                         clear_page_dirty_for_io(bd_page);
1662                                         set_page_writeback(bd_page);
1663                                         unlock_page(bd_page);
1664                                         bd_page = bh->b_page;
1665                                 }
1666                                 break;
1667                         }
1668                         if (bh->b_page != fs_page) {
1669                                 err = nilfs_begin_page_io(fs_page, list);
1670                                 if (unlikely(err)) {
1671                                         *failed_page = fs_page;
1672                                         goto out;
1673                                 }
1674                                 fs_page = bh->b_page;
1675                         }
1676                 }
1677         }
1678         if (bd_page) {
1679                 lock_page(bd_page);
1680                 clear_page_dirty_for_io(bd_page);
1681                 set_page_writeback(bd_page);
1682                 unlock_page(bd_page);
1683         }
1684         err = nilfs_begin_page_io(fs_page, list);
1685         if (unlikely(err))
1686                 *failed_page = fs_page;
1687  out:
1688         return err;
1689 }
1690
1691 static int nilfs_segctor_write(struct nilfs_sc_info *sci,
1692                                struct the_nilfs *nilfs)
1693 {
1694         int ret;
1695
1696         ret = nilfs_write_logs(&sci->sc_segbufs, nilfs);
1697         list_splice_tail_init(&sci->sc_segbufs, &sci->sc_write_logs);
1698         return ret;
1699 }
1700
1701 static void __nilfs_end_page_io(struct page *page, int err)
1702 {
1703         if (!err) {
1704                 if (!nilfs_page_buffers_clean(page))
1705                         __set_page_dirty_nobuffers(page);
1706                 ClearPageError(page);
1707         } else {
1708                 __set_page_dirty_nobuffers(page);
1709                 SetPageError(page);
1710         }
1711
1712         if (buffer_nilfs_allocated(page_buffers(page))) {
1713                 if (TestClearPageWriteback(page))
1714                         dec_zone_page_state(page, NR_WRITEBACK);
1715         } else
1716                 end_page_writeback(page);
1717 }
1718
1719 static void nilfs_end_page_io(struct page *page, int err)
1720 {
1721         if (!page)
1722                 return;
1723
1724         if (buffer_nilfs_node(page_buffers(page)) && !PageWriteback(page)) {
1725                 /*
1726                  * For b-tree node pages, this function may be called twice
1727                  * or more because they might be split in a segment.
1728                  */
1729                 if (PageDirty(page)) {
1730                         /*
1731                          * For pages holding split b-tree node buffers, dirty
1732                          * flag on the buffers may be cleared discretely.
1733                          * In that case, the page is once redirtied for
1734                          * remaining buffers, and it must be cancelled if
1735                          * all the buffers get cleaned later.
1736                          */
1737                         lock_page(page);
1738                         if (nilfs_page_buffers_clean(page))
1739                                 __nilfs_clear_page_dirty(page);
1740                         unlock_page(page);
1741                 }
1742                 return;
1743         }
1744
1745         __nilfs_end_page_io(page, err);
1746 }
1747
1748 static void nilfs_clear_copied_buffers(struct list_head *list, int err)
1749 {
1750         struct buffer_head *bh, *head;
1751         struct page *page;
1752
1753         while (!list_empty(list)) {
1754                 bh = list_entry(list->next, struct buffer_head,
1755                                 b_assoc_buffers);
1756                 page = bh->b_page;
1757                 page_cache_get(page);
1758                 head = bh = page_buffers(page);
1759                 do {
1760                         if (!list_empty(&bh->b_assoc_buffers)) {
1761                                 list_del_init(&bh->b_assoc_buffers);
1762                                 if (!err) {
1763                                         set_buffer_uptodate(bh);
1764                                         clear_buffer_dirty(bh);
1765                                         clear_buffer_delay(bh);
1766                                         clear_buffer_nilfs_volatile(bh);
1767                                 }
1768                                 brelse(bh); /* for b_assoc_buffers */
1769                         }
1770                 } while ((bh = bh->b_this_page) != head);
1771
1772                 __nilfs_end_page_io(page, err);
1773                 page_cache_release(page);
1774         }
1775 }
1776
1777 static void nilfs_abort_logs(struct list_head *logs, struct page *failed_page,
1778                              int err)
1779 {
1780         struct nilfs_segment_buffer *segbuf;
1781         struct page *bd_page = NULL, *fs_page = NULL;
1782         struct buffer_head *bh;
1783
1784         if (list_empty(logs))
1785                 return;
1786
1787         list_for_each_entry(segbuf, logs, sb_list) {
1788                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1789                                     b_assoc_buffers) {
1790                         if (bh->b_page != bd_page) {
1791                                 if (bd_page)
1792                                         end_page_writeback(bd_page);
1793                                 bd_page = bh->b_page;
1794                         }
1795                 }
1796
1797                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1798                                     b_assoc_buffers) {
1799                         if (bh == segbuf->sb_super_root) {
1800                                 if (bh->b_page != bd_page) {
1801                                         end_page_writeback(bd_page);
1802                                         bd_page = bh->b_page;
1803                                 }
1804                                 break;
1805                         }
1806                         if (bh->b_page != fs_page) {
1807                                 nilfs_end_page_io(fs_page, err);
1808                                 if (fs_page && fs_page == failed_page)
1809                                         return;
1810                                 fs_page = bh->b_page;
1811                         }
1812                 }
1813         }
1814         if (bd_page)
1815                 end_page_writeback(bd_page);
1816
1817         nilfs_end_page_io(fs_page, err);
1818 }
1819
1820 static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
1821                                              struct the_nilfs *nilfs, int err)
1822 {
1823         LIST_HEAD(logs);
1824         int ret;
1825
1826         list_splice_tail_init(&sci->sc_write_logs, &logs);
1827         ret = nilfs_wait_on_logs(&logs);
1828         nilfs_abort_logs(&logs, NULL, ret ? : err);
1829
1830         list_splice_tail_init(&sci->sc_segbufs, &logs);
1831         nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
1832         nilfs_free_incomplete_logs(&logs, nilfs);
1833         nilfs_clear_copied_buffers(&sci->sc_copied_buffers, err);
1834
1835         if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
1836                 ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
1837                                                 sci->sc_freesegs,
1838                                                 sci->sc_nfreesegs,
1839                                                 NULL);
1840                 WARN_ON(ret); /* do not happen */
1841         }
1842
1843         nilfs_destroy_logs(&logs);
1844 }
1845
1846 static void nilfs_set_next_segment(struct the_nilfs *nilfs,
1847                                    struct nilfs_segment_buffer *segbuf)
1848 {
1849         nilfs->ns_segnum = segbuf->sb_segnum;
1850         nilfs->ns_nextnum = segbuf->sb_nextnum;
1851         nilfs->ns_pseg_offset = segbuf->sb_pseg_start - segbuf->sb_fseg_start
1852                 + segbuf->sb_sum.nblocks;
1853         nilfs->ns_seg_seq = segbuf->sb_sum.seg_seq;
1854         nilfs->ns_ctime = segbuf->sb_sum.ctime;
1855 }
1856
1857 static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
1858 {
1859         struct nilfs_segment_buffer *segbuf;
1860         struct page *bd_page = NULL, *fs_page = NULL;
1861         struct the_nilfs *nilfs = sci->sc_sbi->s_nilfs;
1862         int update_sr = false;
1863
1864         list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
1865                 struct buffer_head *bh;
1866
1867                 list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
1868                                     b_assoc_buffers) {
1869                         set_buffer_uptodate(bh);
1870                         clear_buffer_dirty(bh);
1871                         if (bh->b_page != bd_page) {
1872                                 if (bd_page)
1873                                         end_page_writeback(bd_page);
1874                                 bd_page = bh->b_page;
1875                         }
1876                 }
1877                 /*
1878                  * We assume that the buffers which belong to the same page
1879                  * continue over the buffer list.
1880                  * Under this assumption, the last BHs of pages is
1881                  * identifiable by the discontinuity of bh->b_page
1882                  * (page != fs_page).
1883                  *
1884                  * For B-tree node blocks, however, this assumption is not
1885                  * guaranteed.  The cleanup code of B-tree node pages needs
1886                  * special care.
1887                  */
1888                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
1889                                     b_assoc_buffers) {
1890                         set_buffer_uptodate(bh);
1891                         clear_buffer_dirty(bh);
1892                         clear_buffer_delay(bh);
1893                         clear_buffer_nilfs_volatile(bh);
1894                         clear_buffer_nilfs_redirected(bh);
1895                         if (bh == segbuf->sb_super_root) {
1896                                 if (bh->b_page != bd_page) {
1897                                         end_page_writeback(bd_page);
1898                                         bd_page = bh->b_page;
1899                                 }
1900                                 update_sr = true;
1901                                 break;
1902                         }
1903                         if (bh->b_page != fs_page) {
1904                                 nilfs_end_page_io(fs_page, 0);
1905                                 fs_page = bh->b_page;
1906                         }
1907                 }
1908
1909                 if (!nilfs_segbuf_simplex(segbuf)) {
1910                         if (segbuf->sb_sum.flags & NILFS_SS_LOGBGN) {
1911                                 set_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1912                                 sci->sc_lseg_stime = jiffies;
1913                         }
1914                         if (segbuf->sb_sum.flags & NILFS_SS_LOGEND)
1915                                 clear_bit(NILFS_SC_UNCLOSED, &sci->sc_flags);
1916                 }
1917         }
1918         /*
1919          * Since pages may continue over multiple segment buffers,
1920          * end of the last page must be checked outside of the loop.
1921          */
1922         if (bd_page)
1923                 end_page_writeback(bd_page);
1924
1925         nilfs_end_page_io(fs_page, 0);
1926
1927         nilfs_clear_copied_buffers(&sci->sc_copied_buffers, 0);
1928
1929         nilfs_drop_collected_inodes(&sci->sc_dirty_files);
1930
1931         if (nilfs_doing_gc())
1932                 nilfs_drop_collected_inodes(&sci->sc_gc_inodes);
1933         else
1934                 nilfs->ns_nongc_ctime = sci->sc_seg_ctime;
1935
1936         sci->sc_nblk_inc += sci->sc_nblk_this_inc;
1937
1938         segbuf = NILFS_LAST_SEGBUF(&sci->sc_write_logs);
1939         nilfs_set_next_segment(nilfs, segbuf);
1940
1941         if (update_sr) {
1942                 nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
1943                                        segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
1944
1945                 clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
1946                 clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
1947                 set_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1948                 nilfs_segctor_clear_metadata_dirty(sci);
1949         } else
1950                 clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
1951 }
1952
1953 static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
1954 {
1955         int ret;
1956
1957         ret = nilfs_wait_on_logs(&sci->sc_write_logs);
1958         if (!ret) {
1959                 nilfs_segctor_complete_write(sci);
1960                 nilfs_destroy_logs(&sci->sc_write_logs);
1961         }
1962         return ret;
1963 }
1964
1965 static int nilfs_segctor_collect_dirty_files(struct nilfs_sc_info *sci,
1966                                              struct the_nilfs *nilfs)
1967 {
1968         struct nilfs_inode_info *ii, *n;
1969         struct inode *ifile = sci->sc_root->ifile;
1970
1971         spin_lock(&nilfs->ns_inode_lock);
1972  retry:
1973         list_for_each_entry_safe(ii, n, &nilfs->ns_dirty_files, i_dirty) {
1974                 if (!ii->i_bh) {
1975                         struct buffer_head *ibh;
1976                         int err;
1977
1978                         spin_unlock(&nilfs->ns_inode_lock);
1979                         err = nilfs_ifile_get_inode_block(
1980                                 ifile, ii->vfs_inode.i_ino, &ibh);
1981                         if (unlikely(err)) {
1982                                 nilfs_warning(sci->sc_super, __func__,
1983                                               "failed to get inode block.\n");
1984                                 return err;
1985                         }
1986                         nilfs_mdt_mark_buffer_dirty(ibh);
1987                         nilfs_mdt_mark_dirty(ifile);
1988                         spin_lock(&nilfs->ns_inode_lock);
1989                         if (likely(!ii->i_bh))
1990                                 ii->i_bh = ibh;
1991                         else
1992                                 brelse(ibh);
1993                         goto retry;
1994                 }
1995
1996                 clear_bit(NILFS_I_QUEUED, &ii->i_state);
1997                 set_bit(NILFS_I_BUSY, &ii->i_state);
1998                 list_del(&ii->i_dirty);
1999                 list_add_tail(&ii->i_dirty, &sci->sc_dirty_files);
2000         }
2001         spin_unlock(&nilfs->ns_inode_lock);
2002
2003         return 0;
2004 }
2005
2006 static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
2007                                              struct the_nilfs *nilfs)
2008 {
2009         struct nilfs_transaction_info *ti = current->journal_info;
2010         struct nilfs_inode_info *ii, *n;
2011
2012         spin_lock(&nilfs->ns_inode_lock);
2013         list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
2014                 if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
2015                     test_bit(NILFS_I_DIRTY, &ii->i_state))
2016                         continue;
2017
2018                 clear_bit(NILFS_I_BUSY, &ii->i_state);
2019                 brelse(ii->i_bh);
2020                 ii->i_bh = NULL;
2021                 list_del(&ii->i_dirty);
2022                 list_add_tail(&ii->i_dirty, &ti->ti_garbage);
2023         }
2024         spin_unlock(&nilfs->ns_inode_lock);
2025 }
2026
2027 /*
2028  * Main procedure of segment constructor
2029  */
2030 static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
2031 {
2032         struct nilfs_sb_info *sbi = sci->sc_sbi;
2033         struct the_nilfs *nilfs = sbi->s_nilfs;
2034         struct page *failed_page;
2035         int err;
2036
2037         sci->sc_stage.scnt = NILFS_ST_INIT;
2038         sci->sc_cno = nilfs->ns_cno;
2039
2040         err = nilfs_segctor_collect_dirty_files(sci, nilfs);
2041         if (unlikely(err))
2042                 goto out;
2043
2044         if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
2045                 set_bit(NILFS_SC_DIRTY, &sci->sc_flags);
2046
2047         if (nilfs_segctor_clean(sci))
2048                 goto out;
2049
2050         do {
2051                 sci->sc_stage.flags &= ~NILFS_CF_HISTORY_MASK;
2052
2053                 err = nilfs_segctor_begin_construction(sci, nilfs);
2054                 if (unlikely(err))
2055                         goto out;
2056
2057                 /* Update time stamp */
2058                 sci->sc_seg_ctime = get_seconds();
2059
2060                 err = nilfs_segctor_collect(sci, nilfs, mode);
2061                 if (unlikely(err))
2062                         goto failed;
2063
2064                 /* Avoid empty segment */
2065                 if (sci->sc_stage.scnt == NILFS_ST_DONE &&
2066                     nilfs_segbuf_empty(sci->sc_curseg)) {
2067                         nilfs_segctor_abort_construction(sci, nilfs, 1);
2068                         goto out;
2069                 }
2070
2071                 err = nilfs_segctor_assign(sci, mode);
2072                 if (unlikely(err))
2073                         goto failed;
2074
2075                 if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2076                         nilfs_segctor_fill_in_file_bmap(sci);
2077
2078                 if (mode == SC_LSEG_SR &&
2079                     sci->sc_stage.scnt >= NILFS_ST_CPFILE) {
2080                         err = nilfs_segctor_fill_in_checkpoint(sci);
2081                         if (unlikely(err))
2082                                 goto failed_to_write;
2083
2084                         nilfs_segctor_fill_in_super_root(sci, nilfs);
2085                 }
2086                 nilfs_segctor_update_segusage(sci, nilfs->ns_sufile);
2087
2088                 /* Write partial segments */
2089                 err = nilfs_segctor_prepare_write(sci, &failed_page);
2090                 if (err) {
2091                         nilfs_abort_logs(&sci->sc_segbufs, failed_page, err);
2092                         goto failed_to_write;
2093                 }
2094
2095                 nilfs_add_checksums_on_logs(&sci->sc_segbufs,
2096                                             nilfs->ns_crc_seed);
2097
2098                 err = nilfs_segctor_write(sci, nilfs);
2099                 if (unlikely(err))
2100                         goto failed_to_write;
2101
2102                 if (sci->sc_stage.scnt == NILFS_ST_DONE ||
2103                     nilfs->ns_blocksize_bits != PAGE_CACHE_SHIFT) {
2104                         /*
2105                          * At this point, we avoid double buffering
2106                          * for blocksize < pagesize because page dirty
2107                          * flag is turned off during write and dirty
2108                          * buffers are not properly collected for
2109                          * pages crossing over segments.
2110                          */
2111                         err = nilfs_segctor_wait(sci);
2112                         if (err)
2113                                 goto failed_to_write;
2114                 }
2115         } while (sci->sc_stage.scnt != NILFS_ST_DONE);
2116
2117  out:
2118         nilfs_segctor_drop_written_files(sci, nilfs);
2119         return err;
2120
2121  failed_to_write:
2122         if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
2123                 nilfs_redirty_inodes(&sci->sc_dirty_files);
2124
2125  failed:
2126         if (nilfs_doing_gc())
2127                 nilfs_redirty_inodes(&sci->sc_gc_inodes);
2128         nilfs_segctor_abort_construction(sci, nilfs, err);
2129         goto out;
2130 }
2131
2132 /**
2133  * nilfs_segctor_start_timer - set timer of background write
2134  * @sci: nilfs_sc_info
2135  *
2136  * If the timer has already been set, it ignores the new request.
2137  * This function MUST be called within a section locking the segment
2138  * semaphore.
2139  */
2140 static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
2141 {
2142         spin_lock(&sci->sc_state_lock);
2143         if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
2144                 sci->sc_timer.expires = jiffies + sci->sc_interval;
2145                 add_timer(&sci->sc_timer);
2146                 sci->sc_state |= NILFS_SEGCTOR_COMMIT;
2147         }
2148         spin_unlock(&sci->sc_state_lock);
2149 }
2150
2151 static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
2152 {
2153         spin_lock(&sci->sc_state_lock);
2154         if (!(sci->sc_flush_request & (1 << bn))) {
2155                 unsigned long prev_req = sci->sc_flush_request;
2156
2157                 sci->sc_flush_request |= (1 << bn);
2158                 if (!prev_req)
2159                         wake_up(&sci->sc_wait_daemon);
2160         }
2161         spin_unlock(&sci->sc_state_lock);
2162 }
2163
2164 /**
2165  * nilfs_flush_segment - trigger a segment construction for resource control
2166  * @sb: super block
2167  * @ino: inode number of the file to be flushed out.
2168  */
2169 void nilfs_flush_segment(struct super_block *sb, ino_t ino)
2170 {
2171         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
2172         struct nilfs_sc_info *sci = nilfs->ns_writer;
2173
2174         if (!sci || nilfs_doing_construction())
2175                 return;
2176         nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
2177                                         /* assign bit 0 to data files */
2178 }
2179
2180 struct nilfs_segctor_wait_request {
2181         wait_queue_t    wq;
2182         __u32           seq;
2183         int             err;
2184         atomic_t        done;
2185 };
2186
2187 static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
2188 {
2189         struct nilfs_segctor_wait_request wait_req;
2190         int err = 0;
2191
2192         spin_lock(&sci->sc_state_lock);
2193         init_wait(&wait_req.wq);
2194         wait_req.err = 0;
2195         atomic_set(&wait_req.done, 0);
2196         wait_req.seq = ++sci->sc_seq_request;
2197         spin_unlock(&sci->sc_state_lock);
2198
2199         init_waitqueue_entry(&wait_req.wq, current);
2200         add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
2201         set_current_state(TASK_INTERRUPTIBLE);
2202         wake_up(&sci->sc_wait_daemon);
2203
2204         for (;;) {
2205                 if (atomic_read(&wait_req.done)) {
2206                         err = wait_req.err;
2207                         break;
2208                 }
2209                 if (!signal_pending(current)) {
2210                         schedule();
2211                         continue;
2212                 }
2213                 err = -ERESTARTSYS;
2214                 break;
2215         }
2216         finish_wait(&sci->sc_wait_request, &wait_req.wq);
2217         return err;
2218 }
2219
2220 static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
2221 {
2222         struct nilfs_segctor_wait_request *wrq, *n;
2223         unsigned long flags;
2224
2225         spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
2226         list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.task_list,
2227                                  wq.task_list) {
2228                 if (!atomic_read(&wrq->done) &&
2229                     nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
2230                         wrq->err = err;
2231                         atomic_set(&wrq->done, 1);
2232                 }
2233                 if (atomic_read(&wrq->done)) {
2234                         wrq->wq.func(&wrq->wq,
2235                                      TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
2236                                      0, NULL);
2237                 }
2238         }
2239         spin_unlock_irqrestore(&sci->sc_wait_request.lock, flags);
2240 }
2241
2242 /**
2243  * nilfs_construct_segment - construct a logical segment
2244  * @sb: super block
2245  *
2246  * Return Value: On success, 0 is retured. On errors, one of the following
2247  * negative error code is returned.
2248  *
2249  * %-EROFS - Read only filesystem.
2250  *
2251  * %-EIO - I/O error
2252  *
2253  * %-ENOSPC - No space left on device (only in a panic state).
2254  *
2255  * %-ERESTARTSYS - Interrupted.
2256  *
2257  * %-ENOMEM - Insufficient memory available.
2258  */
2259 int nilfs_construct_segment(struct super_block *sb)
2260 {
2261         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
2262         struct nilfs_sc_info *sci = nilfs->ns_writer;
2263         struct nilfs_transaction_info *ti;
2264         int err;
2265
2266         if (!sci)
2267                 return -EROFS;
2268
2269         /* A call inside transactions causes a deadlock. */
2270         BUG_ON((ti = current->journal_info) && ti->ti_magic == NILFS_TI_MAGIC);
2271
2272         err = nilfs_segctor_sync(sci);
2273         return err;
2274 }
2275
2276 /**
2277  * nilfs_construct_dsync_segment - construct a data-only logical segment
2278  * @sb: super block
2279  * @inode: inode whose data blocks should be written out
2280  * @start: start byte offset
2281  * @end: end byte offset (inclusive)
2282  *
2283  * Return Value: On success, 0 is retured. On errors, one of the following
2284  * negative error code is returned.
2285  *
2286  * %-EROFS - Read only filesystem.
2287  *
2288  * %-EIO - I/O error
2289  *
2290  * %-ENOSPC - No space left on device (only in a panic state).
2291  *
2292  * %-ERESTARTSYS - Interrupted.
2293  *
2294  * %-ENOMEM - Insufficient memory available.
2295  */
2296 int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
2297                                   loff_t start, loff_t end)
2298 {
2299         struct nilfs_sb_info *sbi = NILFS_SB(sb);
2300         struct the_nilfs *nilfs = sbi->s_nilfs;
2301         struct nilfs_sc_info *sci = nilfs->ns_writer;
2302         struct nilfs_inode_info *ii;
2303         struct nilfs_transaction_info ti;
2304         int err = 0;
2305
2306         if (!sci)
2307                 return -EROFS;
2308
2309         nilfs_transaction_lock(sbi, &ti, 0);
2310
2311         ii = NILFS_I(inode);
2312         if (test_bit(NILFS_I_INODE_DIRTY, &ii->i_state) ||
2313             nilfs_test_opt(nilfs, STRICT_ORDER) ||
2314             test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2315             nilfs_discontinued(nilfs)) {
2316                 nilfs_transaction_unlock(sbi);
2317                 err = nilfs_segctor_sync(sci);
2318                 return err;
2319         }
2320
2321         spin_lock(&nilfs->ns_inode_lock);
2322         if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
2323             !test_bit(NILFS_I_BUSY, &ii->i_state)) {
2324                 spin_unlock(&nilfs->ns_inode_lock);
2325                 nilfs_transaction_unlock(sbi);
2326                 return 0;
2327         }
2328         spin_unlock(&nilfs->ns_inode_lock);
2329         sci->sc_dsync_inode = ii;
2330         sci->sc_dsync_start = start;
2331         sci->sc_dsync_end = end;
2332
2333         err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC);
2334
2335         nilfs_transaction_unlock(sbi);
2336         return err;
2337 }
2338
2339 #define FLUSH_FILE_BIT  (0x1) /* data file only */
2340 #define FLUSH_DAT_BIT   (1 << NILFS_DAT_INO) /* DAT only */
2341
2342 /**
2343  * nilfs_segctor_accept - record accepted sequence count of log-write requests
2344  * @sci: segment constructor object
2345  */
2346 static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
2347 {
2348         spin_lock(&sci->sc_state_lock);
2349         sci->sc_seq_accepted = sci->sc_seq_request;
2350         spin_unlock(&sci->sc_state_lock);
2351         del_timer_sync(&sci->sc_timer);
2352 }
2353
2354 /**
2355  * nilfs_segctor_notify - notify the result of request to caller threads
2356  * @sci: segment constructor object
2357  * @mode: mode of log forming
2358  * @err: error code to be notified
2359  */
2360 static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
2361 {
2362         /* Clear requests (even when the construction failed) */
2363         spin_lock(&sci->sc_state_lock);
2364
2365         if (mode == SC_LSEG_SR) {
2366                 sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
2367                 sci->sc_seq_done = sci->sc_seq_accepted;
2368                 nilfs_segctor_wakeup(sci, err);
2369                 sci->sc_flush_request = 0;
2370         } else {
2371                 if (mode == SC_FLUSH_FILE)
2372                         sci->sc_flush_request &= ~FLUSH_FILE_BIT;
2373                 else if (mode == SC_FLUSH_DAT)
2374                         sci->sc_flush_request &= ~FLUSH_DAT_BIT;
2375
2376                 /* re-enable timer if checkpoint creation was not done */
2377                 if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2378                     time_before(jiffies, sci->sc_timer.expires))
2379                         add_timer(&sci->sc_timer);
2380         }
2381         spin_unlock(&sci->sc_state_lock);
2382 }
2383
2384 /**
2385  * nilfs_segctor_construct - form logs and write them to disk
2386  * @sci: segment constructor object
2387  * @mode: mode of log forming
2388  */
2389 static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
2390 {
2391         struct nilfs_sb_info *sbi = sci->sc_sbi;
2392         struct the_nilfs *nilfs = sbi->s_nilfs;
2393         struct nilfs_super_block **sbp;
2394         int err = 0;
2395
2396         nilfs_segctor_accept(sci);
2397
2398         if (nilfs_discontinued(nilfs))
2399                 mode = SC_LSEG_SR;
2400         if (!nilfs_segctor_confirm(sci))
2401                 err = nilfs_segctor_do_construct(sci, mode);
2402
2403         if (likely(!err)) {
2404                 if (mode != SC_FLUSH_DAT)
2405                         atomic_set(&nilfs->ns_ndirtyblks, 0);
2406                 if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
2407                     nilfs_discontinued(nilfs)) {
2408                         down_write(&nilfs->ns_sem);
2409                         err = -EIO;
2410                         sbp = nilfs_prepare_super(sbi,
2411                                                   nilfs_sb_will_flip(nilfs));
2412                         if (likely(sbp)) {
2413                                 nilfs_set_log_cursor(sbp[0], nilfs);
2414                                 err = nilfs_commit_super(sbi, NILFS_SB_COMMIT);
2415                         }
2416                         up_write(&nilfs->ns_sem);
2417                 }
2418         }
2419
2420         nilfs_segctor_notify(sci, mode, err);
2421         return err;
2422 }
2423
2424 static void nilfs_construction_timeout(unsigned long data)
2425 {
2426         struct task_struct *p = (struct task_struct *)data;
2427         wake_up_process(p);
2428 }
2429
2430 static void
2431 nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
2432 {
2433         struct nilfs_inode_info *ii, *n;
2434
2435         list_for_each_entry_safe(ii, n, head, i_dirty) {
2436                 if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
2437                         continue;
2438                 list_del_init(&ii->i_dirty);
2439                 iput(&ii->vfs_inode);
2440         }
2441 }
2442
2443 int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
2444                          void **kbufs)
2445 {
2446         struct nilfs_sb_info *sbi = NILFS_SB(sb);
2447         struct the_nilfs *nilfs = sbi->s_nilfs;
2448         struct nilfs_sc_info *sci = nilfs->ns_writer;
2449         struct nilfs_transaction_info ti;
2450         int err;
2451
2452         if (unlikely(!sci))
2453                 return -EROFS;
2454
2455         nilfs_transaction_lock(sbi, &ti, 1);
2456
2457         err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
2458         if (unlikely(err))
2459                 goto out_unlock;
2460
2461         err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
2462         if (unlikely(err)) {
2463                 nilfs_mdt_restore_from_shadow_map(nilfs->ns_dat);
2464                 goto out_unlock;
2465         }
2466
2467         sci->sc_freesegs = kbufs[4];
2468         sci->sc_nfreesegs = argv[4].v_nmembs;
2469         list_splice_tail_init(&nilfs->ns_gc_inodes, &sci->sc_gc_inodes);
2470
2471         for (;;) {
2472                 err = nilfs_segctor_construct(sci, SC_LSEG_SR);
2473                 nilfs_remove_written_gcinodes(nilfs, &sci->sc_gc_inodes);
2474
2475                 if (likely(!err))
2476                         break;
2477
2478                 nilfs_warning(sb, __func__,
2479                               "segment construction failed. (err=%d)", err);
2480                 set_current_state(TASK_INTERRUPTIBLE);
2481                 schedule_timeout(sci->sc_interval);
2482         }
2483         if (nilfs_test_opt(nilfs, DISCARD)) {
2484                 int ret = nilfs_discard_segments(nilfs, sci->sc_freesegs,
2485                                                  sci->sc_nfreesegs);
2486                 if (ret) {
2487                         printk(KERN_WARNING
2488                                "NILFS warning: error %d on discard request, "
2489                                "turning discards off for the device\n", ret);
2490                         nilfs_clear_opt(nilfs, DISCARD);
2491                 }
2492         }
2493
2494  out_unlock:
2495         sci->sc_freesegs = NULL;
2496         sci->sc_nfreesegs = 0;
2497         nilfs_mdt_clear_shadow_map(nilfs->ns_dat);
2498         nilfs_transaction_unlock(sbi);
2499         return err;
2500 }
2501
2502 static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
2503 {
2504         struct nilfs_sb_info *sbi = sci->sc_sbi;
2505         struct nilfs_transaction_info ti;
2506
2507         nilfs_transaction_lock(sbi, &ti, 0);
2508         nilfs_segctor_construct(sci, mode);
2509
2510         /*
2511          * Unclosed segment should be retried.  We do this using sc_timer.
2512          * Timeout of sc_timer will invoke complete construction which leads
2513          * to close the current logical segment.
2514          */
2515         if (test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags))
2516                 nilfs_segctor_start_timer(sci);
2517
2518         nilfs_transaction_unlock(sbi);
2519 }
2520
2521 static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
2522 {
2523         int mode = 0;
2524         int err;
2525
2526         spin_lock(&sci->sc_state_lock);
2527         mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
2528                 SC_FLUSH_DAT : SC_FLUSH_FILE;
2529         spin_unlock(&sci->sc_state_lock);
2530
2531         if (mode) {
2532                 err = nilfs_segctor_do_construct(sci, mode);
2533
2534                 spin_lock(&sci->sc_state_lock);
2535                 sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
2536                         ~FLUSH_FILE_BIT : ~FLUSH_DAT_BIT;
2537                 spin_unlock(&sci->sc_state_lock);
2538         }
2539         clear_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags);
2540 }
2541
2542 static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
2543 {
2544         if (!test_bit(NILFS_SC_UNCLOSED, &sci->sc_flags) ||
2545             time_before(jiffies, sci->sc_lseg_stime + sci->sc_mjcp_freq)) {
2546                 if (!(sci->sc_flush_request & ~FLUSH_FILE_BIT))
2547                         return SC_FLUSH_FILE;
2548                 else if (!(sci->sc_flush_request & ~FLUSH_DAT_BIT))
2549                         return SC_FLUSH_DAT;
2550         }
2551         return SC_LSEG_SR;
2552 }
2553
2554 /**
2555  * nilfs_segctor_thread - main loop of the segment constructor thread.
2556  * @arg: pointer to a struct nilfs_sc_info.
2557  *
2558  * nilfs_segctor_thread() initializes a timer and serves as a daemon
2559  * to execute segment constructions.
2560  */
2561 static int nilfs_segctor_thread(void *arg)
2562 {
2563         struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
2564         struct the_nilfs *nilfs = sci->sc_sbi->s_nilfs;
2565         int timeout = 0;
2566
2567         sci->sc_timer.data = (unsigned long)current;
2568         sci->sc_timer.function = nilfs_construction_timeout;
2569
2570         /* start sync. */
2571         sci->sc_task = current;
2572         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_start_thread() */
2573         printk(KERN_INFO
2574                "segctord starting. Construction interval = %lu seconds, "
2575                "CP frequency < %lu seconds\n",
2576                sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
2577
2578         spin_lock(&sci->sc_state_lock);
2579  loop:
2580         for (;;) {
2581                 int mode;
2582
2583                 if (sci->sc_state & NILFS_SEGCTOR_QUIT)
2584                         goto end_thread;
2585
2586                 if (timeout || sci->sc_seq_request != sci->sc_seq_done)
2587                         mode = SC_LSEG_SR;
2588                 else if (!sci->sc_flush_request)
2589                         break;
2590                 else
2591                         mode = nilfs_segctor_flush_mode(sci);
2592
2593                 spin_unlock(&sci->sc_state_lock);
2594                 nilfs_segctor_thread_construct(sci, mode);
2595                 spin_lock(&sci->sc_state_lock);
2596                 timeout = 0;
2597         }
2598
2599
2600         if (freezing(current)) {
2601                 spin_unlock(&sci->sc_state_lock);
2602                 refrigerator();
2603                 spin_lock(&sci->sc_state_lock);
2604         } else {
2605                 DEFINE_WAIT(wait);
2606                 int should_sleep = 1;
2607
2608                 prepare_to_wait(&sci->sc_wait_daemon, &wait,
2609                                 TASK_INTERRUPTIBLE);
2610
2611                 if (sci->sc_seq_request != sci->sc_seq_done)
2612                         should_sleep = 0;
2613                 else if (sci->sc_flush_request)
2614                         should_sleep = 0;
2615                 else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
2616                         should_sleep = time_before(jiffies,
2617                                         sci->sc_timer.expires);
2618
2619                 if (should_sleep) {
2620                         spin_unlock(&sci->sc_state_lock);
2621                         schedule();
2622                         spin_lock(&sci->sc_state_lock);
2623                 }
2624                 finish_wait(&sci->sc_wait_daemon, &wait);
2625                 timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
2626                            time_after_eq(jiffies, sci->sc_timer.expires));
2627
2628                 if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
2629                         set_nilfs_discontinued(nilfs);
2630         }
2631         goto loop;
2632
2633  end_thread:
2634         spin_unlock(&sci->sc_state_lock);
2635
2636         /* end sync. */
2637         sci->sc_task = NULL;
2638         wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
2639         return 0;
2640 }
2641
2642 static int nilfs_segctor_start_thread(struct nilfs_sc_info *sci)
2643 {
2644         struct task_struct *t;
2645
2646         t = kthread_run(nilfs_segctor_thread, sci, "segctord");
2647         if (IS_ERR(t)) {
2648                 int err = PTR_ERR(t);
2649
2650                 printk(KERN_ERR "NILFS: error %d creating segctord thread\n",
2651                        err);
2652                 return err;
2653         }
2654         wait_event(sci->sc_wait_task, sci->sc_task != NULL);
2655         return 0;
2656 }
2657
2658 static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
2659         __acquires(&sci->sc_state_lock)
2660         __releases(&sci->sc_state_lock)
2661 {
2662         sci->sc_state |= NILFS_SEGCTOR_QUIT;
2663
2664         while (sci->sc_task) {
2665                 wake_up(&sci->sc_wait_daemon);
2666                 spin_unlock(&sci->sc_state_lock);
2667                 wait_event(sci->sc_wait_task, sci->sc_task == NULL);
2668                 spin_lock(&sci->sc_state_lock);
2669         }
2670 }
2671
2672 /*
2673  * Setup & clean-up functions
2674  */
2675 static struct nilfs_sc_info *nilfs_segctor_new(struct nilfs_sb_info *sbi,
2676                                                struct nilfs_root *root)
2677 {
2678         struct the_nilfs *nilfs = sbi->s_nilfs;
2679         struct nilfs_sc_info *sci;
2680
2681         sci = kzalloc(sizeof(*sci), GFP_KERNEL);
2682         if (!sci)
2683                 return NULL;
2684
2685         sci->sc_sbi = sbi;
2686         sci->sc_super = sbi->s_super;
2687
2688         nilfs_get_root(root);
2689         sci->sc_root = root;
2690
2691         init_waitqueue_head(&sci->sc_wait_request);
2692         init_waitqueue_head(&sci->sc_wait_daemon);
2693         init_waitqueue_head(&sci->sc_wait_task);
2694         spin_lock_init(&sci->sc_state_lock);
2695         INIT_LIST_HEAD(&sci->sc_dirty_files);
2696         INIT_LIST_HEAD(&sci->sc_segbufs);
2697         INIT_LIST_HEAD(&sci->sc_write_logs);
2698         INIT_LIST_HEAD(&sci->sc_gc_inodes);
2699         INIT_LIST_HEAD(&sci->sc_copied_buffers);
2700         init_timer(&sci->sc_timer);
2701
2702         sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
2703         sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
2704         sci->sc_watermark = NILFS_SC_DEFAULT_WATERMARK;
2705
2706         if (nilfs->ns_interval)
2707                 sci->sc_interval = nilfs->ns_interval;
2708         if (nilfs->ns_watermark)
2709                 sci->sc_watermark = nilfs->ns_watermark;
2710         return sci;
2711 }
2712
2713 static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
2714 {
2715         int ret, retrycount = NILFS_SC_CLEANUP_RETRY;
2716
2717         /* The segctord thread was stopped and its timer was removed.
2718            But some tasks remain. */
2719         do {
2720                 struct nilfs_sb_info *sbi = sci->sc_sbi;
2721                 struct nilfs_transaction_info ti;
2722
2723                 nilfs_transaction_lock(sbi, &ti, 0);
2724                 ret = nilfs_segctor_construct(sci, SC_LSEG_SR);
2725                 nilfs_transaction_unlock(sbi);
2726
2727         } while (ret && retrycount-- > 0);
2728 }
2729
2730 /**
2731  * nilfs_segctor_destroy - destroy the segment constructor.
2732  * @sci: nilfs_sc_info
2733  *
2734  * nilfs_segctor_destroy() kills the segctord thread and frees
2735  * the nilfs_sc_info struct.
2736  * Caller must hold the segment semaphore.
2737  */
2738 static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
2739 {
2740         struct the_nilfs *nilfs = sci->sc_sbi->s_nilfs;
2741         int flag;
2742
2743         up_write(&nilfs->ns_segctor_sem);
2744
2745         spin_lock(&sci->sc_state_lock);
2746         nilfs_segctor_kill_thread(sci);
2747         flag = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) || sci->sc_flush_request
2748                 || sci->sc_seq_request != sci->sc_seq_done);
2749         spin_unlock(&sci->sc_state_lock);
2750
2751         if (flag || !nilfs_segctor_confirm(sci))
2752                 nilfs_segctor_write_out(sci);
2753
2754         WARN_ON(!list_empty(&sci->sc_copied_buffers));
2755
2756         if (!list_empty(&sci->sc_dirty_files)) {
2757                 nilfs_warning(sci->sc_super, __func__,
2758                               "dirty file(s) after the final construction\n");
2759                 nilfs_dispose_list(nilfs, &sci->sc_dirty_files, 1);
2760         }
2761
2762         WARN_ON(!list_empty(&sci->sc_segbufs));
2763         WARN_ON(!list_empty(&sci->sc_write_logs));
2764
2765         nilfs_put_root(sci->sc_root);
2766
2767         down_write(&nilfs->ns_segctor_sem);
2768
2769         del_timer_sync(&sci->sc_timer);
2770         kfree(sci);
2771 }
2772
2773 /**
2774  * nilfs_attach_segment_constructor - attach a segment constructor
2775  * @sbi: nilfs_sb_info
2776  * @root: root object of the current filesystem tree
2777  *
2778  * nilfs_attach_segment_constructor() allocates a struct nilfs_sc_info,
2779  * initializes it, and starts the segment constructor.
2780  *
2781  * Return Value: On success, 0 is returned. On error, one of the following
2782  * negative error code is returned.
2783  *
2784  * %-ENOMEM - Insufficient memory available.
2785  */
2786 int nilfs_attach_segment_constructor(struct nilfs_sb_info *sbi,
2787                                      struct nilfs_root *root)
2788 {
2789         struct the_nilfs *nilfs = sbi->s_nilfs;
2790         int err;
2791
2792         if (nilfs->ns_writer) {
2793                 /*
2794                  * This happens if the filesystem was remounted
2795                  * read/write after nilfs_error degenerated it into a
2796                  * read-only mount.
2797                  */
2798                 nilfs_detach_segment_constructor(sbi);
2799         }
2800
2801         nilfs->ns_writer = nilfs_segctor_new(sbi, root);
2802         if (!nilfs->ns_writer)
2803                 return -ENOMEM;
2804
2805         err = nilfs_segctor_start_thread(nilfs->ns_writer);
2806         if (err) {
2807                 kfree(nilfs->ns_writer);
2808                 nilfs->ns_writer = NULL;
2809         }
2810         return err;
2811 }
2812
2813 /**
2814  * nilfs_detach_segment_constructor - destroy the segment constructor
2815  * @sbi: nilfs_sb_info
2816  *
2817  * nilfs_detach_segment_constructor() kills the segment constructor daemon,
2818  * frees the struct nilfs_sc_info, and destroy the dirty file list.
2819  */
2820 void nilfs_detach_segment_constructor(struct nilfs_sb_info *sbi)
2821 {
2822         struct the_nilfs *nilfs = sbi->s_nilfs;
2823         LIST_HEAD(garbage_list);
2824
2825         down_write(&nilfs->ns_segctor_sem);
2826         if (nilfs->ns_writer) {
2827                 nilfs_segctor_destroy(nilfs->ns_writer);
2828                 nilfs->ns_writer = NULL;
2829         }
2830
2831         /* Force to free the list of dirty files */
2832         spin_lock(&nilfs->ns_inode_lock);
2833         if (!list_empty(&nilfs->ns_dirty_files)) {
2834                 list_splice_init(&nilfs->ns_dirty_files, &garbage_list);
2835                 nilfs_warning(sbi->s_super, __func__,
2836                               "Non empty dirty list after the last "
2837                               "segment construction\n");
2838         }
2839         spin_unlock(&nilfs->ns_inode_lock);
2840         up_write(&nilfs->ns_segctor_sem);
2841
2842         nilfs_dispose_list(nilfs, &garbage_list, 1);
2843 }