Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke...
[linux-2.6.git] / fs / nilfs2 / the_nilfs.c
1 /*
2  * the_nilfs.c - the_nilfs shared structure.
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/buffer_head.h>
25 #include <linux/slab.h>
26 #include <linux/blkdev.h>
27 #include <linux/backing-dev.h>
28 #include <linux/crc32.h>
29 #include "nilfs.h"
30 #include "segment.h"
31 #include "alloc.h"
32 #include "cpfile.h"
33 #include "sufile.h"
34 #include "dat.h"
35 #include "segbuf.h"
36
37
38 static int nilfs_valid_sb(struct nilfs_super_block *sbp);
39
40 void nilfs_set_last_segment(struct the_nilfs *nilfs,
41                             sector_t start_blocknr, u64 seq, __u64 cno)
42 {
43         spin_lock(&nilfs->ns_last_segment_lock);
44         nilfs->ns_last_pseg = start_blocknr;
45         nilfs->ns_last_seq = seq;
46         nilfs->ns_last_cno = cno;
47
48         if (!nilfs_sb_dirty(nilfs)) {
49                 if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
50                         goto stay_cursor;
51
52                 set_nilfs_sb_dirty(nilfs);
53         }
54         nilfs->ns_prev_seq = nilfs->ns_last_seq;
55
56  stay_cursor:
57         spin_unlock(&nilfs->ns_last_segment_lock);
58 }
59
60 /**
61  * alloc_nilfs - allocate a nilfs object
62  * @bdev: block device to which the_nilfs is related
63  *
64  * Return Value: On success, pointer to the_nilfs is returned.
65  * On error, NULL is returned.
66  */
67 struct the_nilfs *alloc_nilfs(struct block_device *bdev)
68 {
69         struct the_nilfs *nilfs;
70
71         nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
72         if (!nilfs)
73                 return NULL;
74
75         nilfs->ns_bdev = bdev;
76         atomic_set(&nilfs->ns_ndirtyblks, 0);
77         init_rwsem(&nilfs->ns_sem);
78         INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
79         spin_lock_init(&nilfs->ns_last_segment_lock);
80         nilfs->ns_cptree = RB_ROOT;
81         spin_lock_init(&nilfs->ns_cptree_lock);
82         init_rwsem(&nilfs->ns_segctor_sem);
83
84         return nilfs;
85 }
86
87 /**
88  * destroy_nilfs - destroy nilfs object
89  * @nilfs: nilfs object to be released
90  */
91 void destroy_nilfs(struct the_nilfs *nilfs)
92 {
93         might_sleep();
94         if (nilfs_init(nilfs)) {
95                 brelse(nilfs->ns_sbh[0]);
96                 brelse(nilfs->ns_sbh[1]);
97         }
98         kfree(nilfs);
99 }
100
101 static int nilfs_load_super_root(struct the_nilfs *nilfs,
102                                  struct super_block *sb, sector_t sr_block)
103 {
104         struct buffer_head *bh_sr;
105         struct nilfs_super_root *raw_sr;
106         struct nilfs_super_block **sbp = nilfs->ns_sbp;
107         struct nilfs_inode *rawi;
108         unsigned dat_entry_size, segment_usage_size, checkpoint_size;
109         unsigned inode_size;
110         int err;
111
112         err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
113         if (unlikely(err))
114                 return err;
115
116         down_read(&nilfs->ns_sem);
117         dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
118         checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
119         segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
120         up_read(&nilfs->ns_sem);
121
122         inode_size = nilfs->ns_inode_size;
123
124         rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
125         err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
126         if (err)
127                 goto failed;
128
129         rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
130         err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
131         if (err)
132                 goto failed_dat;
133
134         rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
135         err = nilfs_sufile_read(sb, segment_usage_size, rawi,
136                                 &nilfs->ns_sufile);
137         if (err)
138                 goto failed_cpfile;
139
140         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
141         nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
142
143  failed:
144         brelse(bh_sr);
145         return err;
146
147  failed_cpfile:
148         iput(nilfs->ns_cpfile);
149
150  failed_dat:
151         iput(nilfs->ns_dat);
152         goto failed;
153 }
154
155 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
156 {
157         memset(ri, 0, sizeof(*ri));
158         INIT_LIST_HEAD(&ri->ri_used_segments);
159 }
160
161 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
162 {
163         nilfs_dispose_segment_list(&ri->ri_used_segments);
164 }
165
166 /**
167  * nilfs_store_log_cursor - load log cursor from a super block
168  * @nilfs: nilfs object
169  * @sbp: buffer storing super block to be read
170  *
171  * nilfs_store_log_cursor() reads the last position of the log
172  * containing a super root from a given super block, and initializes
173  * relevant information on the nilfs object preparatory for log
174  * scanning and recovery.
175  */
176 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
177                                   struct nilfs_super_block *sbp)
178 {
179         int ret = 0;
180
181         nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
182         nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
183         nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
184
185         nilfs->ns_prev_seq = nilfs->ns_last_seq;
186         nilfs->ns_seg_seq = nilfs->ns_last_seq;
187         nilfs->ns_segnum =
188                 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
189         nilfs->ns_cno = nilfs->ns_last_cno + 1;
190         if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
191                 printk(KERN_ERR "NILFS invalid last segment number.\n");
192                 ret = -EINVAL;
193         }
194         return ret;
195 }
196
197 /**
198  * load_nilfs - load and recover the nilfs
199  * @nilfs: the_nilfs structure to be released
200  * @sbi: nilfs_sb_info used to recover past segment
201  *
202  * load_nilfs() searches and load the latest super root,
203  * attaches the last segment, and does recovery if needed.
204  * The caller must call this exclusively for simultaneous mounts.
205  */
206 int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
207 {
208         struct nilfs_recovery_info ri;
209         unsigned int s_flags = sbi->s_super->s_flags;
210         int really_read_only = bdev_read_only(nilfs->ns_bdev);
211         int valid_fs = nilfs_valid_fs(nilfs);
212         int err;
213
214         if (!valid_fs) {
215                 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
216                 if (s_flags & MS_RDONLY) {
217                         printk(KERN_INFO "NILFS: INFO: recovery "
218                                "required for readonly filesystem.\n");
219                         printk(KERN_INFO "NILFS: write access will "
220                                "be enabled during recovery.\n");
221                 }
222         }
223
224         nilfs_init_recovery_info(&ri);
225
226         err = nilfs_search_super_root(nilfs, &ri);
227         if (unlikely(err)) {
228                 struct nilfs_super_block **sbp = nilfs->ns_sbp;
229                 int blocksize;
230
231                 if (err != -EINVAL)
232                         goto scan_error;
233
234                 if (!nilfs_valid_sb(sbp[1])) {
235                         printk(KERN_WARNING
236                                "NILFS warning: unable to fall back to spare"
237                                "super block\n");
238                         goto scan_error;
239                 }
240                 printk(KERN_INFO
241                        "NILFS: try rollback from an earlier position\n");
242
243                 /*
244                  * restore super block with its spare and reconfigure
245                  * relevant states of the nilfs object.
246                  */
247                 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
248                 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
249                 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
250
251                 /* verify consistency between two super blocks */
252                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
253                 if (blocksize != nilfs->ns_blocksize) {
254                         printk(KERN_WARNING
255                                "NILFS warning: blocksize differs between "
256                                "two super blocks (%d != %d)\n",
257                                blocksize, nilfs->ns_blocksize);
258                         goto scan_error;
259                 }
260
261                 err = nilfs_store_log_cursor(nilfs, sbp[0]);
262                 if (err)
263                         goto scan_error;
264
265                 /* drop clean flag to allow roll-forward and recovery */
266                 nilfs->ns_mount_state &= ~NILFS_VALID_FS;
267                 valid_fs = 0;
268
269                 err = nilfs_search_super_root(nilfs, &ri);
270                 if (err)
271                         goto scan_error;
272         }
273
274         err = nilfs_load_super_root(nilfs, sbi->s_super, ri.ri_super_root);
275         if (unlikely(err)) {
276                 printk(KERN_ERR "NILFS: error loading super root.\n");
277                 goto failed;
278         }
279
280         if (valid_fs)
281                 goto skip_recovery;
282
283         if (s_flags & MS_RDONLY) {
284                 __u64 features;
285
286                 if (nilfs_test_opt(sbi, NORECOVERY)) {
287                         printk(KERN_INFO "NILFS: norecovery option specified. "
288                                "skipping roll-forward recovery\n");
289                         goto skip_recovery;
290                 }
291                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
292                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
293                 if (features) {
294                         printk(KERN_ERR "NILFS: couldn't proceed with "
295                                "recovery because of unsupported optional "
296                                "features (%llx)\n",
297                                (unsigned long long)features);
298                         err = -EROFS;
299                         goto failed_unload;
300                 }
301                 if (really_read_only) {
302                         printk(KERN_ERR "NILFS: write access "
303                                "unavailable, cannot proceed.\n");
304                         err = -EROFS;
305                         goto failed_unload;
306                 }
307                 sbi->s_super->s_flags &= ~MS_RDONLY;
308         } else if (nilfs_test_opt(sbi, NORECOVERY)) {
309                 printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
310                        "option was specified for a read/write mount\n");
311                 err = -EINVAL;
312                 goto failed_unload;
313         }
314
315         err = nilfs_salvage_orphan_logs(nilfs, sbi, &ri);
316         if (err)
317                 goto failed_unload;
318
319         down_write(&nilfs->ns_sem);
320         nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
321         err = nilfs_cleanup_super(sbi);
322         up_write(&nilfs->ns_sem);
323
324         if (err) {
325                 printk(KERN_ERR "NILFS: failed to update super block. "
326                        "recovery unfinished.\n");
327                 goto failed_unload;
328         }
329         printk(KERN_INFO "NILFS: recovery complete.\n");
330
331  skip_recovery:
332         set_nilfs_loaded(nilfs);
333         nilfs_clear_recovery_info(&ri);
334         sbi->s_super->s_flags = s_flags;
335         return 0;
336
337  scan_error:
338         printk(KERN_ERR "NILFS: error searching super root.\n");
339         goto failed;
340
341  failed_unload:
342         iput(nilfs->ns_cpfile);
343         iput(nilfs->ns_sufile);
344         iput(nilfs->ns_dat);
345
346  failed:
347         nilfs_clear_recovery_info(&ri);
348         sbi->s_super->s_flags = s_flags;
349         return err;
350 }
351
352 static unsigned long long nilfs_max_size(unsigned int blkbits)
353 {
354         unsigned int max_bits;
355         unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
356
357         max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
358         if (max_bits < 64)
359                 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
360         return res;
361 }
362
363 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
364                                    struct nilfs_super_block *sbp)
365 {
366         if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
367                 printk(KERN_ERR "NILFS: unsupported revision "
368                        "(superblock rev.=%d.%d, current rev.=%d.%d). "
369                        "Please check the version of mkfs.nilfs.\n",
370                        le32_to_cpu(sbp->s_rev_level),
371                        le16_to_cpu(sbp->s_minor_rev_level),
372                        NILFS_CURRENT_REV, NILFS_MINOR_REV);
373                 return -EINVAL;
374         }
375         nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
376         if (nilfs->ns_sbsize > BLOCK_SIZE)
377                 return -EINVAL;
378
379         nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
380         nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
381
382         nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
383         if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
384                 printk(KERN_ERR "NILFS: too short segment.\n");
385                 return -EINVAL;
386         }
387
388         nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
389         nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
390         nilfs->ns_r_segments_percentage =
391                 le32_to_cpu(sbp->s_r_segments_percentage);
392         nilfs->ns_nrsvsegs =
393                 max_t(unsigned long, NILFS_MIN_NRSVSEGS,
394                       DIV_ROUND_UP(nilfs->ns_nsegments *
395                                    nilfs->ns_r_segments_percentage, 100));
396         nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
397         return 0;
398 }
399
400 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
401 {
402         static unsigned char sum[4];
403         const int sumoff = offsetof(struct nilfs_super_block, s_sum);
404         size_t bytes;
405         u32 crc;
406
407         if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
408                 return 0;
409         bytes = le16_to_cpu(sbp->s_bytes);
410         if (bytes > BLOCK_SIZE)
411                 return 0;
412         crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
413                        sumoff);
414         crc = crc32_le(crc, sum, 4);
415         crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
416                        bytes - sumoff - 4);
417         return crc == le32_to_cpu(sbp->s_sum);
418 }
419
420 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
421 {
422         return offset < ((le64_to_cpu(sbp->s_nsegments) *
423                           le32_to_cpu(sbp->s_blocks_per_segment)) <<
424                          (le32_to_cpu(sbp->s_log_block_size) + 10));
425 }
426
427 static void nilfs_release_super_block(struct the_nilfs *nilfs)
428 {
429         int i;
430
431         for (i = 0; i < 2; i++) {
432                 if (nilfs->ns_sbp[i]) {
433                         brelse(nilfs->ns_sbh[i]);
434                         nilfs->ns_sbh[i] = NULL;
435                         nilfs->ns_sbp[i] = NULL;
436                 }
437         }
438 }
439
440 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
441 {
442         brelse(nilfs->ns_sbh[0]);
443         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
444         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
445         nilfs->ns_sbh[1] = NULL;
446         nilfs->ns_sbp[1] = NULL;
447 }
448
449 void nilfs_swap_super_block(struct the_nilfs *nilfs)
450 {
451         struct buffer_head *tsbh = nilfs->ns_sbh[0];
452         struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
453
454         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
455         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
456         nilfs->ns_sbh[1] = tsbh;
457         nilfs->ns_sbp[1] = tsbp;
458 }
459
460 static int nilfs_load_super_block(struct the_nilfs *nilfs,
461                                   struct super_block *sb, int blocksize,
462                                   struct nilfs_super_block **sbpp)
463 {
464         struct nilfs_super_block **sbp = nilfs->ns_sbp;
465         struct buffer_head **sbh = nilfs->ns_sbh;
466         u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
467         int valid[2], swp = 0;
468
469         sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
470                                         &sbh[0]);
471         sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
472
473         if (!sbp[0]) {
474                 if (!sbp[1]) {
475                         printk(KERN_ERR "NILFS: unable to read superblock\n");
476                         return -EIO;
477                 }
478                 printk(KERN_WARNING
479                        "NILFS warning: unable to read primary superblock\n");
480         } else if (!sbp[1])
481                 printk(KERN_WARNING
482                        "NILFS warning: unable to read secondary superblock\n");
483
484         /*
485          * Compare two super blocks and set 1 in swp if the secondary
486          * super block is valid and newer.  Otherwise, set 0 in swp.
487          */
488         valid[0] = nilfs_valid_sb(sbp[0]);
489         valid[1] = nilfs_valid_sb(sbp[1]);
490         swp = valid[1] && (!valid[0] ||
491                            le64_to_cpu(sbp[1]->s_last_cno) >
492                            le64_to_cpu(sbp[0]->s_last_cno));
493
494         if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
495                 brelse(sbh[1]);
496                 sbh[1] = NULL;
497                 sbp[1] = NULL;
498                 swp = 0;
499         }
500         if (!valid[swp]) {
501                 nilfs_release_super_block(nilfs);
502                 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
503                        sb->s_id);
504                 return -EINVAL;
505         }
506
507         if (!valid[!swp])
508                 printk(KERN_WARNING "NILFS warning: broken superblock. "
509                        "using spare superblock.\n");
510         if (swp)
511                 nilfs_swap_super_block(nilfs);
512
513         nilfs->ns_sbwcount = 0;
514         nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
515         nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
516         *sbpp = sbp[0];
517         return 0;
518 }
519
520 /**
521  * init_nilfs - initialize a NILFS instance.
522  * @nilfs: the_nilfs structure
523  * @sbi: nilfs_sb_info
524  * @sb: super block
525  * @data: mount options
526  *
527  * init_nilfs() performs common initialization per block device (e.g.
528  * reading the super block, getting disk layout information, initializing
529  * shared fields in the_nilfs).
530  *
531  * Return Value: On success, 0 is returned. On error, a negative error
532  * code is returned.
533  */
534 int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
535 {
536         struct super_block *sb = sbi->s_super;
537         struct nilfs_super_block *sbp;
538         int blocksize;
539         int err;
540
541         down_write(&nilfs->ns_sem);
542
543         blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
544         if (!blocksize) {
545                 printk(KERN_ERR "NILFS: unable to set blocksize\n");
546                 err = -EINVAL;
547                 goto out;
548         }
549         err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
550         if (err)
551                 goto out;
552
553         err = nilfs_store_magic_and_option(sb, sbp, data);
554         if (err)
555                 goto failed_sbh;
556
557         err = nilfs_check_feature_compatibility(sb, sbp);
558         if (err)
559                 goto failed_sbh;
560
561         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
562         if (blocksize < NILFS_MIN_BLOCK_SIZE ||
563             blocksize > NILFS_MAX_BLOCK_SIZE) {
564                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
565                        "filesystem blocksize %d\n", blocksize);
566                 err = -EINVAL;
567                 goto failed_sbh;
568         }
569         if (sb->s_blocksize != blocksize) {
570                 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
571
572                 if (blocksize < hw_blocksize) {
573                         printk(KERN_ERR
574                                "NILFS: blocksize %d too small for device "
575                                "(sector-size = %d).\n",
576                                blocksize, hw_blocksize);
577                         err = -EINVAL;
578                         goto failed_sbh;
579                 }
580                 nilfs_release_super_block(nilfs);
581                 sb_set_blocksize(sb, blocksize);
582
583                 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
584                 if (err)
585                         goto out;
586                         /* not failed_sbh; sbh is released automatically
587                            when reloading fails. */
588         }
589         nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
590         nilfs->ns_blocksize = blocksize;
591
592         err = nilfs_store_disk_layout(nilfs, sbp);
593         if (err)
594                 goto failed_sbh;
595
596         sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
597
598         nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
599
600         err = nilfs_store_log_cursor(nilfs, sbp);
601         if (err)
602                 goto failed_sbh;
603
604         set_nilfs_init(nilfs);
605         err = 0;
606  out:
607         up_write(&nilfs->ns_sem);
608         return err;
609
610  failed_sbh:
611         nilfs_release_super_block(nilfs);
612         goto out;
613 }
614
615 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
616                             size_t nsegs)
617 {
618         sector_t seg_start, seg_end;
619         sector_t start = 0, nblocks = 0;
620         unsigned int sects_per_block;
621         __u64 *sn;
622         int ret = 0;
623
624         sects_per_block = (1 << nilfs->ns_blocksize_bits) /
625                 bdev_logical_block_size(nilfs->ns_bdev);
626         for (sn = segnump; sn < segnump + nsegs; sn++) {
627                 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
628
629                 if (!nblocks) {
630                         start = seg_start;
631                         nblocks = seg_end - seg_start + 1;
632                 } else if (start + nblocks == seg_start) {
633                         nblocks += seg_end - seg_start + 1;
634                 } else {
635                         ret = blkdev_issue_discard(nilfs->ns_bdev,
636                                                    start * sects_per_block,
637                                                    nblocks * sects_per_block,
638                                                    GFP_NOFS, 0);
639                         if (ret < 0)
640                                 return ret;
641                         nblocks = 0;
642                 }
643         }
644         if (nblocks)
645                 ret = blkdev_issue_discard(nilfs->ns_bdev,
646                                            start * sects_per_block,
647                                            nblocks * sects_per_block,
648                                            GFP_NOFS, 0);
649         return ret;
650 }
651
652 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
653 {
654         struct inode *dat = nilfs_dat_inode(nilfs);
655         unsigned long ncleansegs;
656
657         down_read(&NILFS_MDT(dat)->mi_sem);     /* XXX */
658         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
659         up_read(&NILFS_MDT(dat)->mi_sem);       /* XXX */
660         *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
661         return 0;
662 }
663
664 int nilfs_near_disk_full(struct the_nilfs *nilfs)
665 {
666         unsigned long ncleansegs, nincsegs;
667
668         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
669         nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
670                 nilfs->ns_blocks_per_segment + 1;
671
672         return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
673 }
674
675 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
676 {
677         struct rb_node *n;
678         struct nilfs_root *root;
679
680         spin_lock(&nilfs->ns_cptree_lock);
681         n = nilfs->ns_cptree.rb_node;
682         while (n) {
683                 root = rb_entry(n, struct nilfs_root, rb_node);
684
685                 if (cno < root->cno) {
686                         n = n->rb_left;
687                 } else if (cno > root->cno) {
688                         n = n->rb_right;
689                 } else {
690                         atomic_inc(&root->count);
691                         spin_unlock(&nilfs->ns_cptree_lock);
692                         return root;
693                 }
694         }
695         spin_unlock(&nilfs->ns_cptree_lock);
696
697         return NULL;
698 }
699
700 struct nilfs_root *
701 nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
702 {
703         struct rb_node **p, *parent;
704         struct nilfs_root *root, *new;
705
706         root = nilfs_lookup_root(nilfs, cno);
707         if (root)
708                 return root;
709
710         new = kmalloc(sizeof(*root), GFP_KERNEL);
711         if (!new)
712                 return NULL;
713
714         spin_lock(&nilfs->ns_cptree_lock);
715
716         p = &nilfs->ns_cptree.rb_node;
717         parent = NULL;
718
719         while (*p) {
720                 parent = *p;
721                 root = rb_entry(parent, struct nilfs_root, rb_node);
722
723                 if (cno < root->cno) {
724                         p = &(*p)->rb_left;
725                 } else if (cno > root->cno) {
726                         p = &(*p)->rb_right;
727                 } else {
728                         atomic_inc(&root->count);
729                         spin_unlock(&nilfs->ns_cptree_lock);
730                         kfree(new);
731                         return root;
732                 }
733         }
734
735         new->cno = cno;
736         new->ifile = NULL;
737         new->nilfs = nilfs;
738         atomic_set(&new->count, 1);
739         atomic_set(&new->inodes_count, 0);
740         atomic_set(&new->blocks_count, 0);
741
742         rb_link_node(&new->rb_node, parent, p);
743         rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
744
745         spin_unlock(&nilfs->ns_cptree_lock);
746
747         return new;
748 }
749
750 void nilfs_put_root(struct nilfs_root *root)
751 {
752         if (atomic_dec_and_test(&root->count)) {
753                 struct the_nilfs *nilfs = root->nilfs;
754
755                 spin_lock(&nilfs->ns_cptree_lock);
756                 rb_erase(&root->rb_node, &nilfs->ns_cptree);
757                 spin_unlock(&nilfs->ns_cptree_lock);
758                 if (root->ifile)
759                         iput(root->ifile);
760
761                 kfree(root);
762         }
763 }