nilfs2: add truncation routine of segment usage file
[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/random.h>
29 #include <linux/crc32.h>
30 #include "nilfs.h"
31 #include "segment.h"
32 #include "alloc.h"
33 #include "cpfile.h"
34 #include "sufile.h"
35 #include "dat.h"
36 #include "segbuf.h"
37
38
39 static int nilfs_valid_sb(struct nilfs_super_block *sbp);
40
41 void nilfs_set_last_segment(struct the_nilfs *nilfs,
42                             sector_t start_blocknr, u64 seq, __u64 cno)
43 {
44         spin_lock(&nilfs->ns_last_segment_lock);
45         nilfs->ns_last_pseg = start_blocknr;
46         nilfs->ns_last_seq = seq;
47         nilfs->ns_last_cno = cno;
48
49         if (!nilfs_sb_dirty(nilfs)) {
50                 if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
51                         goto stay_cursor;
52
53                 set_nilfs_sb_dirty(nilfs);
54         }
55         nilfs->ns_prev_seq = nilfs->ns_last_seq;
56
57  stay_cursor:
58         spin_unlock(&nilfs->ns_last_segment_lock);
59 }
60
61 /**
62  * alloc_nilfs - allocate a nilfs object
63  * @bdev: block device to which the_nilfs is related
64  *
65  * Return Value: On success, pointer to the_nilfs is returned.
66  * On error, NULL is returned.
67  */
68 struct the_nilfs *alloc_nilfs(struct block_device *bdev)
69 {
70         struct the_nilfs *nilfs;
71
72         nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
73         if (!nilfs)
74                 return NULL;
75
76         nilfs->ns_bdev = bdev;
77         atomic_set(&nilfs->ns_ndirtyblks, 0);
78         init_rwsem(&nilfs->ns_sem);
79         INIT_LIST_HEAD(&nilfs->ns_dirty_files);
80         INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
81         spin_lock_init(&nilfs->ns_inode_lock);
82         spin_lock_init(&nilfs->ns_next_gen_lock);
83         spin_lock_init(&nilfs->ns_last_segment_lock);
84         nilfs->ns_cptree = RB_ROOT;
85         spin_lock_init(&nilfs->ns_cptree_lock);
86         init_rwsem(&nilfs->ns_segctor_sem);
87
88         return nilfs;
89 }
90
91 /**
92  * destroy_nilfs - destroy nilfs object
93  * @nilfs: nilfs object to be released
94  */
95 void destroy_nilfs(struct the_nilfs *nilfs)
96 {
97         might_sleep();
98         if (nilfs_init(nilfs)) {
99                 brelse(nilfs->ns_sbh[0]);
100                 brelse(nilfs->ns_sbh[1]);
101         }
102         kfree(nilfs);
103 }
104
105 static int nilfs_load_super_root(struct the_nilfs *nilfs,
106                                  struct super_block *sb, sector_t sr_block)
107 {
108         struct buffer_head *bh_sr;
109         struct nilfs_super_root *raw_sr;
110         struct nilfs_super_block **sbp = nilfs->ns_sbp;
111         struct nilfs_inode *rawi;
112         unsigned dat_entry_size, segment_usage_size, checkpoint_size;
113         unsigned inode_size;
114         int err;
115
116         err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
117         if (unlikely(err))
118                 return err;
119
120         down_read(&nilfs->ns_sem);
121         dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
122         checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
123         segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
124         up_read(&nilfs->ns_sem);
125
126         inode_size = nilfs->ns_inode_size;
127
128         rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
129         err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
130         if (err)
131                 goto failed;
132
133         rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
134         err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
135         if (err)
136                 goto failed_dat;
137
138         rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
139         err = nilfs_sufile_read(sb, segment_usage_size, rawi,
140                                 &nilfs->ns_sufile);
141         if (err)
142                 goto failed_cpfile;
143
144         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
145         nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
146
147  failed:
148         brelse(bh_sr);
149         return err;
150
151  failed_cpfile:
152         iput(nilfs->ns_cpfile);
153
154  failed_dat:
155         iput(nilfs->ns_dat);
156         goto failed;
157 }
158
159 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
160 {
161         memset(ri, 0, sizeof(*ri));
162         INIT_LIST_HEAD(&ri->ri_used_segments);
163 }
164
165 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
166 {
167         nilfs_dispose_segment_list(&ri->ri_used_segments);
168 }
169
170 /**
171  * nilfs_store_log_cursor - load log cursor from a super block
172  * @nilfs: nilfs object
173  * @sbp: buffer storing super block to be read
174  *
175  * nilfs_store_log_cursor() reads the last position of the log
176  * containing a super root from a given super block, and initializes
177  * relevant information on the nilfs object preparatory for log
178  * scanning and recovery.
179  */
180 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
181                                   struct nilfs_super_block *sbp)
182 {
183         int ret = 0;
184
185         nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
186         nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
187         nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
188
189         nilfs->ns_prev_seq = nilfs->ns_last_seq;
190         nilfs->ns_seg_seq = nilfs->ns_last_seq;
191         nilfs->ns_segnum =
192                 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
193         nilfs->ns_cno = nilfs->ns_last_cno + 1;
194         if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
195                 printk(KERN_ERR "NILFS invalid last segment number.\n");
196                 ret = -EINVAL;
197         }
198         return ret;
199 }
200
201 /**
202  * load_nilfs - load and recover the nilfs
203  * @nilfs: the_nilfs structure to be released
204  * @sb: super block isntance used to recover past segment
205  *
206  * load_nilfs() searches and load the latest super root,
207  * attaches the last segment, and does recovery if needed.
208  * The caller must call this exclusively for simultaneous mounts.
209  */
210 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
211 {
212         struct nilfs_recovery_info ri;
213         unsigned int s_flags = sb->s_flags;
214         int really_read_only = bdev_read_only(nilfs->ns_bdev);
215         int valid_fs = nilfs_valid_fs(nilfs);
216         int err;
217
218         if (!valid_fs) {
219                 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
220                 if (s_flags & MS_RDONLY) {
221                         printk(KERN_INFO "NILFS: INFO: recovery "
222                                "required for readonly filesystem.\n");
223                         printk(KERN_INFO "NILFS: write access will "
224                                "be enabled during recovery.\n");
225                 }
226         }
227
228         nilfs_init_recovery_info(&ri);
229
230         err = nilfs_search_super_root(nilfs, &ri);
231         if (unlikely(err)) {
232                 struct nilfs_super_block **sbp = nilfs->ns_sbp;
233                 int blocksize;
234
235                 if (err != -EINVAL)
236                         goto scan_error;
237
238                 if (!nilfs_valid_sb(sbp[1])) {
239                         printk(KERN_WARNING
240                                "NILFS warning: unable to fall back to spare"
241                                "super block\n");
242                         goto scan_error;
243                 }
244                 printk(KERN_INFO
245                        "NILFS: try rollback from an earlier position\n");
246
247                 /*
248                  * restore super block with its spare and reconfigure
249                  * relevant states of the nilfs object.
250                  */
251                 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
252                 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
253                 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
254
255                 /* verify consistency between two super blocks */
256                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
257                 if (blocksize != nilfs->ns_blocksize) {
258                         printk(KERN_WARNING
259                                "NILFS warning: blocksize differs between "
260                                "two super blocks (%d != %d)\n",
261                                blocksize, nilfs->ns_blocksize);
262                         goto scan_error;
263                 }
264
265                 err = nilfs_store_log_cursor(nilfs, sbp[0]);
266                 if (err)
267                         goto scan_error;
268
269                 /* drop clean flag to allow roll-forward and recovery */
270                 nilfs->ns_mount_state &= ~NILFS_VALID_FS;
271                 valid_fs = 0;
272
273                 err = nilfs_search_super_root(nilfs, &ri);
274                 if (err)
275                         goto scan_error;
276         }
277
278         err = nilfs_load_super_root(nilfs, sb, ri.ri_super_root);
279         if (unlikely(err)) {
280                 printk(KERN_ERR "NILFS: error loading super root.\n");
281                 goto failed;
282         }
283
284         if (valid_fs)
285                 goto skip_recovery;
286
287         if (s_flags & MS_RDONLY) {
288                 __u64 features;
289
290                 if (nilfs_test_opt(nilfs, NORECOVERY)) {
291                         printk(KERN_INFO "NILFS: norecovery option specified. "
292                                "skipping roll-forward recovery\n");
293                         goto skip_recovery;
294                 }
295                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
296                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
297                 if (features) {
298                         printk(KERN_ERR "NILFS: couldn't proceed with "
299                                "recovery because of unsupported optional "
300                                "features (%llx)\n",
301                                (unsigned long long)features);
302                         err = -EROFS;
303                         goto failed_unload;
304                 }
305                 if (really_read_only) {
306                         printk(KERN_ERR "NILFS: write access "
307                                "unavailable, cannot proceed.\n");
308                         err = -EROFS;
309                         goto failed_unload;
310                 }
311                 sb->s_flags &= ~MS_RDONLY;
312         } else if (nilfs_test_opt(nilfs, NORECOVERY)) {
313                 printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
314                        "option was specified for a read/write mount\n");
315                 err = -EINVAL;
316                 goto failed_unload;
317         }
318
319         err = nilfs_salvage_orphan_logs(nilfs, sb, &ri);
320         if (err)
321                 goto failed_unload;
322
323         down_write(&nilfs->ns_sem);
324         nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
325         err = nilfs_cleanup_super(sb);
326         up_write(&nilfs->ns_sem);
327
328         if (err) {
329                 printk(KERN_ERR "NILFS: failed to update super block. "
330                        "recovery unfinished.\n");
331                 goto failed_unload;
332         }
333         printk(KERN_INFO "NILFS: recovery complete.\n");
334
335  skip_recovery:
336         nilfs_clear_recovery_info(&ri);
337         sb->s_flags = s_flags;
338         return 0;
339
340  scan_error:
341         printk(KERN_ERR "NILFS: error searching super root.\n");
342         goto failed;
343
344  failed_unload:
345         iput(nilfs->ns_cpfile);
346         iput(nilfs->ns_sufile);
347         iput(nilfs->ns_dat);
348
349  failed:
350         nilfs_clear_recovery_info(&ri);
351         sb->s_flags = s_flags;
352         return err;
353 }
354
355 static unsigned long long nilfs_max_size(unsigned int blkbits)
356 {
357         unsigned int max_bits;
358         unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
359
360         max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
361         if (max_bits < 64)
362                 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
363         return res;
364 }
365
366 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
367                                    struct nilfs_super_block *sbp)
368 {
369         if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
370                 printk(KERN_ERR "NILFS: unsupported revision "
371                        "(superblock rev.=%d.%d, current rev.=%d.%d). "
372                        "Please check the version of mkfs.nilfs.\n",
373                        le32_to_cpu(sbp->s_rev_level),
374                        le16_to_cpu(sbp->s_minor_rev_level),
375                        NILFS_CURRENT_REV, NILFS_MINOR_REV);
376                 return -EINVAL;
377         }
378         nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
379         if (nilfs->ns_sbsize > BLOCK_SIZE)
380                 return -EINVAL;
381
382         nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
383         nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
384
385         nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
386         if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
387                 printk(KERN_ERR "NILFS: too short segment.\n");
388                 return -EINVAL;
389         }
390
391         nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
392         nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
393         nilfs->ns_r_segments_percentage =
394                 le32_to_cpu(sbp->s_r_segments_percentage);
395         nilfs->ns_nrsvsegs =
396                 max_t(unsigned long, NILFS_MIN_NRSVSEGS,
397                       DIV_ROUND_UP(nilfs->ns_nsegments *
398                                    nilfs->ns_r_segments_percentage, 100));
399         nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
400         return 0;
401 }
402
403 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
404 {
405         static unsigned char sum[4];
406         const int sumoff = offsetof(struct nilfs_super_block, s_sum);
407         size_t bytes;
408         u32 crc;
409
410         if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
411                 return 0;
412         bytes = le16_to_cpu(sbp->s_bytes);
413         if (bytes > BLOCK_SIZE)
414                 return 0;
415         crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
416                        sumoff);
417         crc = crc32_le(crc, sum, 4);
418         crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
419                        bytes - sumoff - 4);
420         return crc == le32_to_cpu(sbp->s_sum);
421 }
422
423 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
424 {
425         return offset < ((le64_to_cpu(sbp->s_nsegments) *
426                           le32_to_cpu(sbp->s_blocks_per_segment)) <<
427                          (le32_to_cpu(sbp->s_log_block_size) + 10));
428 }
429
430 static void nilfs_release_super_block(struct the_nilfs *nilfs)
431 {
432         int i;
433
434         for (i = 0; i < 2; i++) {
435                 if (nilfs->ns_sbp[i]) {
436                         brelse(nilfs->ns_sbh[i]);
437                         nilfs->ns_sbh[i] = NULL;
438                         nilfs->ns_sbp[i] = NULL;
439                 }
440         }
441 }
442
443 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
444 {
445         brelse(nilfs->ns_sbh[0]);
446         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
447         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
448         nilfs->ns_sbh[1] = NULL;
449         nilfs->ns_sbp[1] = NULL;
450 }
451
452 void nilfs_swap_super_block(struct the_nilfs *nilfs)
453 {
454         struct buffer_head *tsbh = nilfs->ns_sbh[0];
455         struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
456
457         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
458         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
459         nilfs->ns_sbh[1] = tsbh;
460         nilfs->ns_sbp[1] = tsbp;
461 }
462
463 static int nilfs_load_super_block(struct the_nilfs *nilfs,
464                                   struct super_block *sb, int blocksize,
465                                   struct nilfs_super_block **sbpp)
466 {
467         struct nilfs_super_block **sbp = nilfs->ns_sbp;
468         struct buffer_head **sbh = nilfs->ns_sbh;
469         u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
470         int valid[2], swp = 0;
471
472         sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
473                                         &sbh[0]);
474         sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
475
476         if (!sbp[0]) {
477                 if (!sbp[1]) {
478                         printk(KERN_ERR "NILFS: unable to read superblock\n");
479                         return -EIO;
480                 }
481                 printk(KERN_WARNING
482                        "NILFS warning: unable to read primary superblock "
483                        "(blocksize = %d)\n", blocksize);
484         } else if (!sbp[1]) {
485                 printk(KERN_WARNING
486                        "NILFS warning: unable to read secondary superblock "
487                        "(blocksize = %d)\n", blocksize);
488         }
489
490         /*
491          * Compare two super blocks and set 1 in swp if the secondary
492          * super block is valid and newer.  Otherwise, set 0 in swp.
493          */
494         valid[0] = nilfs_valid_sb(sbp[0]);
495         valid[1] = nilfs_valid_sb(sbp[1]);
496         swp = valid[1] && (!valid[0] ||
497                            le64_to_cpu(sbp[1]->s_last_cno) >
498                            le64_to_cpu(sbp[0]->s_last_cno));
499
500         if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
501                 brelse(sbh[1]);
502                 sbh[1] = NULL;
503                 sbp[1] = NULL;
504                 swp = 0;
505         }
506         if (!valid[swp]) {
507                 nilfs_release_super_block(nilfs);
508                 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
509                        sb->s_id);
510                 return -EINVAL;
511         }
512
513         if (!valid[!swp])
514                 printk(KERN_WARNING "NILFS warning: broken superblock. "
515                        "using spare superblock (blocksize = %d).\n", blocksize);
516         if (swp)
517                 nilfs_swap_super_block(nilfs);
518
519         nilfs->ns_sbwcount = 0;
520         nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
521         nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
522         *sbpp = sbp[0];
523         return 0;
524 }
525
526 /**
527  * init_nilfs - initialize a NILFS instance.
528  * @nilfs: the_nilfs structure
529  * @sb: super block
530  * @data: mount options
531  *
532  * init_nilfs() performs common initialization per block device (e.g.
533  * reading the super block, getting disk layout information, initializing
534  * shared fields in the_nilfs).
535  *
536  * Return Value: On success, 0 is returned. On error, a negative error
537  * code is returned.
538  */
539 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
540 {
541         struct nilfs_super_block *sbp;
542         int blocksize;
543         int err;
544
545         down_write(&nilfs->ns_sem);
546
547         blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
548         if (!blocksize) {
549                 printk(KERN_ERR "NILFS: unable to set blocksize\n");
550                 err = -EINVAL;
551                 goto out;
552         }
553         err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
554         if (err)
555                 goto out;
556
557         err = nilfs_store_magic_and_option(sb, sbp, data);
558         if (err)
559                 goto failed_sbh;
560
561         err = nilfs_check_feature_compatibility(sb, sbp);
562         if (err)
563                 goto failed_sbh;
564
565         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
566         if (blocksize < NILFS_MIN_BLOCK_SIZE ||
567             blocksize > NILFS_MAX_BLOCK_SIZE) {
568                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
569                        "filesystem blocksize %d\n", blocksize);
570                 err = -EINVAL;
571                 goto failed_sbh;
572         }
573         if (sb->s_blocksize != blocksize) {
574                 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
575
576                 if (blocksize < hw_blocksize) {
577                         printk(KERN_ERR
578                                "NILFS: blocksize %d too small for device "
579                                "(sector-size = %d).\n",
580                                blocksize, hw_blocksize);
581                         err = -EINVAL;
582                         goto failed_sbh;
583                 }
584                 nilfs_release_super_block(nilfs);
585                 sb_set_blocksize(sb, blocksize);
586
587                 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
588                 if (err)
589                         goto out;
590                         /* not failed_sbh; sbh is released automatically
591                            when reloading fails. */
592         }
593         nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
594         nilfs->ns_blocksize = blocksize;
595
596         get_random_bytes(&nilfs->ns_next_generation,
597                          sizeof(nilfs->ns_next_generation));
598
599         err = nilfs_store_disk_layout(nilfs, sbp);
600         if (err)
601                 goto failed_sbh;
602
603         sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
604
605         nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
606
607         err = nilfs_store_log_cursor(nilfs, sbp);
608         if (err)
609                 goto failed_sbh;
610
611         set_nilfs_init(nilfs);
612         err = 0;
613  out:
614         up_write(&nilfs->ns_sem);
615         return err;
616
617  failed_sbh:
618         nilfs_release_super_block(nilfs);
619         goto out;
620 }
621
622 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
623                             size_t nsegs)
624 {
625         sector_t seg_start, seg_end;
626         sector_t start = 0, nblocks = 0;
627         unsigned int sects_per_block;
628         __u64 *sn;
629         int ret = 0;
630
631         sects_per_block = (1 << nilfs->ns_blocksize_bits) /
632                 bdev_logical_block_size(nilfs->ns_bdev);
633         for (sn = segnump; sn < segnump + nsegs; sn++) {
634                 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
635
636                 if (!nblocks) {
637                         start = seg_start;
638                         nblocks = seg_end - seg_start + 1;
639                 } else if (start + nblocks == seg_start) {
640                         nblocks += seg_end - seg_start + 1;
641                 } else {
642                         ret = blkdev_issue_discard(nilfs->ns_bdev,
643                                                    start * sects_per_block,
644                                                    nblocks * sects_per_block,
645                                                    GFP_NOFS, 0);
646                         if (ret < 0)
647                                 return ret;
648                         nblocks = 0;
649                 }
650         }
651         if (nblocks)
652                 ret = blkdev_issue_discard(nilfs->ns_bdev,
653                                            start * sects_per_block,
654                                            nblocks * sects_per_block,
655                                            GFP_NOFS, 0);
656         return ret;
657 }
658
659 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
660 {
661         unsigned long ncleansegs;
662
663         down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
664         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
665         up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
666         *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
667         return 0;
668 }
669
670 int nilfs_near_disk_full(struct the_nilfs *nilfs)
671 {
672         unsigned long ncleansegs, nincsegs;
673
674         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
675         nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
676                 nilfs->ns_blocks_per_segment + 1;
677
678         return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
679 }
680
681 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
682 {
683         struct rb_node *n;
684         struct nilfs_root *root;
685
686         spin_lock(&nilfs->ns_cptree_lock);
687         n = nilfs->ns_cptree.rb_node;
688         while (n) {
689                 root = rb_entry(n, struct nilfs_root, rb_node);
690
691                 if (cno < root->cno) {
692                         n = n->rb_left;
693                 } else if (cno > root->cno) {
694                         n = n->rb_right;
695                 } else {
696                         atomic_inc(&root->count);
697                         spin_unlock(&nilfs->ns_cptree_lock);
698                         return root;
699                 }
700         }
701         spin_unlock(&nilfs->ns_cptree_lock);
702
703         return NULL;
704 }
705
706 struct nilfs_root *
707 nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
708 {
709         struct rb_node **p, *parent;
710         struct nilfs_root *root, *new;
711
712         root = nilfs_lookup_root(nilfs, cno);
713         if (root)
714                 return root;
715
716         new = kmalloc(sizeof(*root), GFP_KERNEL);
717         if (!new)
718                 return NULL;
719
720         spin_lock(&nilfs->ns_cptree_lock);
721
722         p = &nilfs->ns_cptree.rb_node;
723         parent = NULL;
724
725         while (*p) {
726                 parent = *p;
727                 root = rb_entry(parent, struct nilfs_root, rb_node);
728
729                 if (cno < root->cno) {
730                         p = &(*p)->rb_left;
731                 } else if (cno > root->cno) {
732                         p = &(*p)->rb_right;
733                 } else {
734                         atomic_inc(&root->count);
735                         spin_unlock(&nilfs->ns_cptree_lock);
736                         kfree(new);
737                         return root;
738                 }
739         }
740
741         new->cno = cno;
742         new->ifile = NULL;
743         new->nilfs = nilfs;
744         atomic_set(&new->count, 1);
745         atomic_set(&new->inodes_count, 0);
746         atomic_set(&new->blocks_count, 0);
747
748         rb_link_node(&new->rb_node, parent, p);
749         rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
750
751         spin_unlock(&nilfs->ns_cptree_lock);
752
753         return new;
754 }
755
756 void nilfs_put_root(struct nilfs_root *root)
757 {
758         if (atomic_dec_and_test(&root->count)) {
759                 struct the_nilfs *nilfs = root->nilfs;
760
761                 spin_lock(&nilfs->ns_cptree_lock);
762                 rb_erase(&root->rb_node, &nilfs->ns_cptree);
763                 spin_unlock(&nilfs->ns_cptree_lock);
764                 if (root->ifile)
765                         iput(root->ifile);
766
767                 kfree(root);
768         }
769 }