fs/nilfs2: fix potential underflow in call to crc32_le
[pandora-kernel.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         mutex_init(&nilfs->ns_snapshot_mount_mutex);
80         INIT_LIST_HEAD(&nilfs->ns_dirty_files);
81         INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
82         spin_lock_init(&nilfs->ns_inode_lock);
83         spin_lock_init(&nilfs->ns_next_gen_lock);
84         spin_lock_init(&nilfs->ns_last_segment_lock);
85         nilfs->ns_cptree = RB_ROOT;
86         spin_lock_init(&nilfs->ns_cptree_lock);
87         init_rwsem(&nilfs->ns_segctor_sem);
88
89         return nilfs;
90 }
91
92 /**
93  * destroy_nilfs - destroy nilfs object
94  * @nilfs: nilfs object to be released
95  */
96 void destroy_nilfs(struct the_nilfs *nilfs)
97 {
98         might_sleep();
99         if (nilfs_init(nilfs)) {
100                 brelse(nilfs->ns_sbh[0]);
101                 brelse(nilfs->ns_sbh[1]);
102         }
103         kfree(nilfs);
104 }
105
106 static int nilfs_load_super_root(struct the_nilfs *nilfs,
107                                  struct super_block *sb, sector_t sr_block)
108 {
109         struct buffer_head *bh_sr;
110         struct nilfs_super_root *raw_sr;
111         struct nilfs_super_block **sbp = nilfs->ns_sbp;
112         struct nilfs_inode *rawi;
113         unsigned dat_entry_size, segment_usage_size, checkpoint_size;
114         unsigned inode_size;
115         int err;
116
117         err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
118         if (unlikely(err))
119                 return err;
120
121         down_read(&nilfs->ns_sem);
122         dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
123         checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
124         segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
125         up_read(&nilfs->ns_sem);
126
127         inode_size = nilfs->ns_inode_size;
128
129         rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
130         err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
131         if (err)
132                 goto failed;
133
134         rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
135         err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
136         if (err)
137                 goto failed_dat;
138
139         rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
140         err = nilfs_sufile_read(sb, segment_usage_size, rawi,
141                                 &nilfs->ns_sufile);
142         if (err)
143                 goto failed_cpfile;
144
145         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
146         nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
147
148  failed:
149         brelse(bh_sr);
150         return err;
151
152  failed_cpfile:
153         iput(nilfs->ns_cpfile);
154
155  failed_dat:
156         iput(nilfs->ns_dat);
157         goto failed;
158 }
159
160 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
161 {
162         memset(ri, 0, sizeof(*ri));
163         INIT_LIST_HEAD(&ri->ri_used_segments);
164 }
165
166 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
167 {
168         nilfs_dispose_segment_list(&ri->ri_used_segments);
169 }
170
171 /**
172  * nilfs_store_log_cursor - load log cursor from a super block
173  * @nilfs: nilfs object
174  * @sbp: buffer storing super block to be read
175  *
176  * nilfs_store_log_cursor() reads the last position of the log
177  * containing a super root from a given super block, and initializes
178  * relevant information on the nilfs object preparatory for log
179  * scanning and recovery.
180  */
181 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
182                                   struct nilfs_super_block *sbp)
183 {
184         int ret = 0;
185
186         nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
187         nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
188         nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
189
190         nilfs->ns_prev_seq = nilfs->ns_last_seq;
191         nilfs->ns_seg_seq = nilfs->ns_last_seq;
192         nilfs->ns_segnum =
193                 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
194         nilfs->ns_cno = nilfs->ns_last_cno + 1;
195         if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
196                 printk(KERN_ERR "NILFS invalid last segment number.\n");
197                 ret = -EINVAL;
198         }
199         return ret;
200 }
201
202 /**
203  * load_nilfs - load and recover the nilfs
204  * @nilfs: the_nilfs structure to be released
205  * @sb: super block isntance used to recover past segment
206  *
207  * load_nilfs() searches and load the latest super root,
208  * attaches the last segment, and does recovery if needed.
209  * The caller must call this exclusively for simultaneous mounts.
210  */
211 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
212 {
213         struct nilfs_recovery_info ri;
214         unsigned int s_flags = sb->s_flags;
215         int really_read_only = bdev_read_only(nilfs->ns_bdev);
216         int valid_fs = nilfs_valid_fs(nilfs);
217         int err;
218
219         if (!valid_fs) {
220                 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
221                 if (s_flags & MS_RDONLY) {
222                         printk(KERN_INFO "NILFS: INFO: recovery "
223                                "required for readonly filesystem.\n");
224                         printk(KERN_INFO "NILFS: write access will "
225                                "be enabled during recovery.\n");
226                 }
227         }
228
229         nilfs_init_recovery_info(&ri);
230
231         err = nilfs_search_super_root(nilfs, &ri);
232         if (unlikely(err)) {
233                 struct nilfs_super_block **sbp = nilfs->ns_sbp;
234                 int blocksize;
235
236                 if (err != -EINVAL)
237                         goto scan_error;
238
239                 if (!nilfs_valid_sb(sbp[1])) {
240                         printk(KERN_WARNING
241                                "NILFS warning: unable to fall back to spare"
242                                "super block\n");
243                         goto scan_error;
244                 }
245                 printk(KERN_INFO
246                        "NILFS: try rollback from an earlier position\n");
247
248                 /*
249                  * restore super block with its spare and reconfigure
250                  * relevant states of the nilfs object.
251                  */
252                 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
253                 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
254                 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
255
256                 /* verify consistency between two super blocks */
257                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
258                 if (blocksize != nilfs->ns_blocksize) {
259                         printk(KERN_WARNING
260                                "NILFS warning: blocksize differs between "
261                                "two super blocks (%d != %d)\n",
262                                blocksize, nilfs->ns_blocksize);
263                         goto scan_error;
264                 }
265
266                 err = nilfs_store_log_cursor(nilfs, sbp[0]);
267                 if (err)
268                         goto scan_error;
269
270                 /* drop clean flag to allow roll-forward and recovery */
271                 nilfs->ns_mount_state &= ~NILFS_VALID_FS;
272                 valid_fs = 0;
273
274                 err = nilfs_search_super_root(nilfs, &ri);
275                 if (err)
276                         goto scan_error;
277         }
278
279         err = nilfs_load_super_root(nilfs, sb, ri.ri_super_root);
280         if (unlikely(err)) {
281                 printk(KERN_ERR "NILFS: error loading super root.\n");
282                 goto failed;
283         }
284
285         if (valid_fs)
286                 goto skip_recovery;
287
288         if (s_flags & MS_RDONLY) {
289                 __u64 features;
290
291                 if (nilfs_test_opt(nilfs, NORECOVERY)) {
292                         printk(KERN_INFO "NILFS: norecovery option specified. "
293                                "skipping roll-forward recovery\n");
294                         goto skip_recovery;
295                 }
296                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
297                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
298                 if (features) {
299                         printk(KERN_ERR "NILFS: couldn't proceed with "
300                                "recovery because of unsupported optional "
301                                "features (%llx)\n",
302                                (unsigned long long)features);
303                         err = -EROFS;
304                         goto failed_unload;
305                 }
306                 if (really_read_only) {
307                         printk(KERN_ERR "NILFS: write access "
308                                "unavailable, cannot proceed.\n");
309                         err = -EROFS;
310                         goto failed_unload;
311                 }
312                 sb->s_flags &= ~MS_RDONLY;
313         } else if (nilfs_test_opt(nilfs, NORECOVERY)) {
314                 printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
315                        "option was specified for a read/write mount\n");
316                 err = -EINVAL;
317                 goto failed_unload;
318         }
319
320         err = nilfs_salvage_orphan_logs(nilfs, sb, &ri);
321         if (err)
322                 goto failed_unload;
323
324         down_write(&nilfs->ns_sem);
325         nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
326         err = nilfs_cleanup_super(sb);
327         up_write(&nilfs->ns_sem);
328
329         if (err) {
330                 printk(KERN_ERR "NILFS: failed to update super block. "
331                        "recovery unfinished.\n");
332                 goto failed_unload;
333         }
334         printk(KERN_INFO "NILFS: recovery complete.\n");
335
336  skip_recovery:
337         nilfs_clear_recovery_info(&ri);
338         sb->s_flags = s_flags;
339         return 0;
340
341  scan_error:
342         printk(KERN_ERR "NILFS: error searching super root.\n");
343         goto failed;
344
345  failed_unload:
346         iput(nilfs->ns_cpfile);
347         iput(nilfs->ns_sufile);
348         iput(nilfs->ns_dat);
349
350  failed:
351         nilfs_clear_recovery_info(&ri);
352         sb->s_flags = s_flags;
353         return err;
354 }
355
356 static unsigned long long nilfs_max_size(unsigned int blkbits)
357 {
358         unsigned int max_bits;
359         unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
360
361         max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
362         if (max_bits < 64)
363                 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
364         return res;
365 }
366
367 /**
368  * nilfs_nrsvsegs - calculate the number of reserved segments
369  * @nilfs: nilfs object
370  * @nsegs: total number of segments
371  */
372 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
373 {
374         return max_t(unsigned long, NILFS_MIN_NRSVSEGS,
375                      DIV_ROUND_UP(nsegs * nilfs->ns_r_segments_percentage,
376                                   100));
377 }
378
379 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs)
380 {
381         nilfs->ns_nsegments = nsegs;
382         nilfs->ns_nrsvsegs = nilfs_nrsvsegs(nilfs, nsegs);
383 }
384
385 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
386                                    struct nilfs_super_block *sbp)
387 {
388         if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
389                 printk(KERN_ERR "NILFS: unsupported revision "
390                        "(superblock rev.=%d.%d, current rev.=%d.%d). "
391                        "Please check the version of mkfs.nilfs.\n",
392                        le32_to_cpu(sbp->s_rev_level),
393                        le16_to_cpu(sbp->s_minor_rev_level),
394                        NILFS_CURRENT_REV, NILFS_MINOR_REV);
395                 return -EINVAL;
396         }
397         nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
398         if (nilfs->ns_sbsize > BLOCK_SIZE)
399                 return -EINVAL;
400
401         nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
402         nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
403
404         nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
405         if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
406                 printk(KERN_ERR "NILFS: too short segment.\n");
407                 return -EINVAL;
408         }
409
410         nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
411         nilfs->ns_r_segments_percentage =
412                 le32_to_cpu(sbp->s_r_segments_percentage);
413         nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments));
414         nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
415         return 0;
416 }
417
418 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
419 {
420         static unsigned char sum[4];
421         const int sumoff = offsetof(struct nilfs_super_block, s_sum);
422         size_t bytes;
423         u32 crc;
424
425         if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
426                 return 0;
427         bytes = le16_to_cpu(sbp->s_bytes);
428         if (bytes < sumoff + 4 || bytes > BLOCK_SIZE)
429                 return 0;
430         crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
431                        sumoff);
432         crc = crc32_le(crc, sum, 4);
433         crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
434                        bytes - sumoff - 4);
435         return crc == le32_to_cpu(sbp->s_sum);
436 }
437
438 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
439 {
440         return offset < ((le64_to_cpu(sbp->s_nsegments) *
441                           le32_to_cpu(sbp->s_blocks_per_segment)) <<
442                          (le32_to_cpu(sbp->s_log_block_size) + 10));
443 }
444
445 static void nilfs_release_super_block(struct the_nilfs *nilfs)
446 {
447         int i;
448
449         for (i = 0; i < 2; i++) {
450                 if (nilfs->ns_sbp[i]) {
451                         brelse(nilfs->ns_sbh[i]);
452                         nilfs->ns_sbh[i] = NULL;
453                         nilfs->ns_sbp[i] = NULL;
454                 }
455         }
456 }
457
458 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
459 {
460         brelse(nilfs->ns_sbh[0]);
461         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
462         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
463         nilfs->ns_sbh[1] = NULL;
464         nilfs->ns_sbp[1] = NULL;
465 }
466
467 void nilfs_swap_super_block(struct the_nilfs *nilfs)
468 {
469         struct buffer_head *tsbh = nilfs->ns_sbh[0];
470         struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
471
472         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
473         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
474         nilfs->ns_sbh[1] = tsbh;
475         nilfs->ns_sbp[1] = tsbp;
476 }
477
478 static int nilfs_load_super_block(struct the_nilfs *nilfs,
479                                   struct super_block *sb, int blocksize,
480                                   struct nilfs_super_block **sbpp)
481 {
482         struct nilfs_super_block **sbp = nilfs->ns_sbp;
483         struct buffer_head **sbh = nilfs->ns_sbh;
484         u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
485         int valid[2], swp = 0;
486
487         sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
488                                         &sbh[0]);
489         sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
490
491         if (!sbp[0]) {
492                 if (!sbp[1]) {
493                         printk(KERN_ERR "NILFS: unable to read superblock\n");
494                         return -EIO;
495                 }
496                 printk(KERN_WARNING
497                        "NILFS warning: unable to read primary superblock "
498                        "(blocksize = %d)\n", blocksize);
499         } else if (!sbp[1]) {
500                 printk(KERN_WARNING
501                        "NILFS warning: unable to read secondary superblock "
502                        "(blocksize = %d)\n", blocksize);
503         }
504
505         /*
506          * Compare two super blocks and set 1 in swp if the secondary
507          * super block is valid and newer.  Otherwise, set 0 in swp.
508          */
509         valid[0] = nilfs_valid_sb(sbp[0]);
510         valid[1] = nilfs_valid_sb(sbp[1]);
511         swp = valid[1] && (!valid[0] ||
512                            le64_to_cpu(sbp[1]->s_last_cno) >
513                            le64_to_cpu(sbp[0]->s_last_cno));
514
515         if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
516                 brelse(sbh[1]);
517                 sbh[1] = NULL;
518                 sbp[1] = NULL;
519                 valid[1] = 0;
520                 swp = 0;
521         }
522         if (!valid[swp]) {
523                 nilfs_release_super_block(nilfs);
524                 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
525                        sb->s_id);
526                 return -EINVAL;
527         }
528
529         if (!valid[!swp])
530                 printk(KERN_WARNING "NILFS warning: broken superblock. "
531                        "using spare superblock (blocksize = %d).\n", blocksize);
532         if (swp)
533                 nilfs_swap_super_block(nilfs);
534
535         nilfs->ns_sbwcount = 0;
536         nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
537         nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
538         *sbpp = sbp[0];
539         return 0;
540 }
541
542 /**
543  * init_nilfs - initialize a NILFS instance.
544  * @nilfs: the_nilfs structure
545  * @sb: super block
546  * @data: mount options
547  *
548  * init_nilfs() performs common initialization per block device (e.g.
549  * reading the super block, getting disk layout information, initializing
550  * shared fields in the_nilfs).
551  *
552  * Return Value: On success, 0 is returned. On error, a negative error
553  * code is returned.
554  */
555 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
556 {
557         struct nilfs_super_block *sbp;
558         int blocksize;
559         int err;
560
561         down_write(&nilfs->ns_sem);
562
563         blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
564         if (!blocksize) {
565                 printk(KERN_ERR "NILFS: unable to set blocksize\n");
566                 err = -EINVAL;
567                 goto out;
568         }
569         err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
570         if (err)
571                 goto out;
572
573         err = nilfs_store_magic_and_option(sb, sbp, data);
574         if (err)
575                 goto failed_sbh;
576
577         err = nilfs_check_feature_compatibility(sb, sbp);
578         if (err)
579                 goto failed_sbh;
580
581         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
582         if (blocksize < NILFS_MIN_BLOCK_SIZE ||
583             blocksize > NILFS_MAX_BLOCK_SIZE) {
584                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
585                        "filesystem blocksize %d\n", blocksize);
586                 err = -EINVAL;
587                 goto failed_sbh;
588         }
589         if (sb->s_blocksize != blocksize) {
590                 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
591
592                 if (blocksize < hw_blocksize) {
593                         printk(KERN_ERR
594                                "NILFS: blocksize %d too small for device "
595                                "(sector-size = %d).\n",
596                                blocksize, hw_blocksize);
597                         err = -EINVAL;
598                         goto failed_sbh;
599                 }
600                 nilfs_release_super_block(nilfs);
601                 sb_set_blocksize(sb, blocksize);
602
603                 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
604                 if (err)
605                         goto out;
606                         /* not failed_sbh; sbh is released automatically
607                            when reloading fails. */
608         }
609         nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
610         nilfs->ns_blocksize = blocksize;
611
612         get_random_bytes(&nilfs->ns_next_generation,
613                          sizeof(nilfs->ns_next_generation));
614
615         err = nilfs_store_disk_layout(nilfs, sbp);
616         if (err)
617                 goto failed_sbh;
618
619         sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
620
621         nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
622
623         err = nilfs_store_log_cursor(nilfs, sbp);
624         if (err)
625                 goto failed_sbh;
626
627         set_nilfs_init(nilfs);
628         err = 0;
629  out:
630         up_write(&nilfs->ns_sem);
631         return err;
632
633  failed_sbh:
634         nilfs_release_super_block(nilfs);
635         goto out;
636 }
637
638 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
639                             size_t nsegs)
640 {
641         sector_t seg_start, seg_end;
642         sector_t start = 0, nblocks = 0;
643         unsigned int sects_per_block;
644         __u64 *sn;
645         int ret = 0;
646
647         sects_per_block = (1 << nilfs->ns_blocksize_bits) /
648                 bdev_logical_block_size(nilfs->ns_bdev);
649         for (sn = segnump; sn < segnump + nsegs; sn++) {
650                 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
651
652                 if (!nblocks) {
653                         start = seg_start;
654                         nblocks = seg_end - seg_start + 1;
655                 } else if (start + nblocks == seg_start) {
656                         nblocks += seg_end - seg_start + 1;
657                 } else {
658                         ret = blkdev_issue_discard(nilfs->ns_bdev,
659                                                    start * sects_per_block,
660                                                    nblocks * sects_per_block,
661                                                    GFP_NOFS, 0);
662                         if (ret < 0)
663                                 return ret;
664                         nblocks = 0;
665                 }
666         }
667         if (nblocks)
668                 ret = blkdev_issue_discard(nilfs->ns_bdev,
669                                            start * sects_per_block,
670                                            nblocks * sects_per_block,
671                                            GFP_NOFS, 0);
672         return ret;
673 }
674
675 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
676 {
677         unsigned long ncleansegs;
678
679         down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
680         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
681         up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
682         *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
683         return 0;
684 }
685
686 int nilfs_near_disk_full(struct the_nilfs *nilfs)
687 {
688         unsigned long ncleansegs, nincsegs;
689
690         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
691         nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
692                 nilfs->ns_blocks_per_segment + 1;
693
694         return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
695 }
696
697 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
698 {
699         struct rb_node *n;
700         struct nilfs_root *root;
701
702         spin_lock(&nilfs->ns_cptree_lock);
703         n = nilfs->ns_cptree.rb_node;
704         while (n) {
705                 root = rb_entry(n, struct nilfs_root, rb_node);
706
707                 if (cno < root->cno) {
708                         n = n->rb_left;
709                 } else if (cno > root->cno) {
710                         n = n->rb_right;
711                 } else {
712                         atomic_inc(&root->count);
713                         spin_unlock(&nilfs->ns_cptree_lock);
714                         return root;
715                 }
716         }
717         spin_unlock(&nilfs->ns_cptree_lock);
718
719         return NULL;
720 }
721
722 struct nilfs_root *
723 nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
724 {
725         struct rb_node **p, *parent;
726         struct nilfs_root *root, *new;
727
728         root = nilfs_lookup_root(nilfs, cno);
729         if (root)
730                 return root;
731
732         new = kmalloc(sizeof(*root), GFP_KERNEL);
733         if (!new)
734                 return NULL;
735
736         spin_lock(&nilfs->ns_cptree_lock);
737
738         p = &nilfs->ns_cptree.rb_node;
739         parent = NULL;
740
741         while (*p) {
742                 parent = *p;
743                 root = rb_entry(parent, struct nilfs_root, rb_node);
744
745                 if (cno < root->cno) {
746                         p = &(*p)->rb_left;
747                 } else if (cno > root->cno) {
748                         p = &(*p)->rb_right;
749                 } else {
750                         atomic_inc(&root->count);
751                         spin_unlock(&nilfs->ns_cptree_lock);
752                         kfree(new);
753                         return root;
754                 }
755         }
756
757         new->cno = cno;
758         new->ifile = NULL;
759         new->nilfs = nilfs;
760         atomic_set(&new->count, 1);
761         atomic_set(&new->inodes_count, 0);
762         atomic_set(&new->blocks_count, 0);
763
764         rb_link_node(&new->rb_node, parent, p);
765         rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
766
767         spin_unlock(&nilfs->ns_cptree_lock);
768
769         return new;
770 }
771
772 void nilfs_put_root(struct nilfs_root *root)
773 {
774         if (atomic_dec_and_test(&root->count)) {
775                 struct the_nilfs *nilfs = root->nilfs;
776
777                 spin_lock(&nilfs->ns_cptree_lock);
778                 rb_erase(&root->rb_node, &nilfs->ns_cptree);
779                 spin_unlock(&nilfs->ns_cptree_lock);
780                 if (root->ifile)
781                         iput(root->ifile);
782
783                 kfree(root);
784         }
785 }