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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
39static int nilfs_valid_sb(struct nilfs_super_block *sbp);
40
41void 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
63
64
65
66
67
68struct 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 nilfs->ns_sb_update_freq = NILFS_SB_FREQ;
89
90 return nilfs;
91}
92
93
94
95
96
97void destroy_nilfs(struct the_nilfs *nilfs)
98{
99 might_sleep();
100 if (nilfs_init(nilfs)) {
101 nilfs_sysfs_delete_device_group(nilfs);
102 brelse(nilfs->ns_sbh[0]);
103 brelse(nilfs->ns_sbh[1]);
104 }
105 kfree(nilfs);
106}
107
108static int nilfs_load_super_root(struct the_nilfs *nilfs,
109 struct super_block *sb, sector_t sr_block)
110{
111 struct buffer_head *bh_sr;
112 struct nilfs_super_root *raw_sr;
113 struct nilfs_super_block **sbp = nilfs->ns_sbp;
114 struct nilfs_inode *rawi;
115 unsigned dat_entry_size, segment_usage_size, checkpoint_size;
116 unsigned inode_size;
117 int err;
118
119 err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
120 if (unlikely(err))
121 return err;
122
123 down_read(&nilfs->ns_sem);
124 dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
125 checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
126 segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
127 up_read(&nilfs->ns_sem);
128
129 inode_size = nilfs->ns_inode_size;
130
131 rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
132 err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
133 if (err)
134 goto failed;
135
136 rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
137 err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
138 if (err)
139 goto failed_dat;
140
141 rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
142 err = nilfs_sufile_read(sb, segment_usage_size, rawi,
143 &nilfs->ns_sufile);
144 if (err)
145 goto failed_cpfile;
146
147 raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
148 nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
149
150 failed:
151 brelse(bh_sr);
152 return err;
153
154 failed_cpfile:
155 iput(nilfs->ns_cpfile);
156
157 failed_dat:
158 iput(nilfs->ns_dat);
159 goto failed;
160}
161
162static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
163{
164 memset(ri, 0, sizeof(*ri));
165 INIT_LIST_HEAD(&ri->ri_used_segments);
166}
167
168static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
169{
170 nilfs_dispose_segment_list(&ri->ri_used_segments);
171}
172
173
174
175
176
177
178
179
180
181
182
183static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
184 struct nilfs_super_block *sbp)
185{
186 int ret = 0;
187
188 nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
189 nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
190 nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
191
192 nilfs->ns_prev_seq = nilfs->ns_last_seq;
193 nilfs->ns_seg_seq = nilfs->ns_last_seq;
194 nilfs->ns_segnum =
195 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
196 nilfs->ns_cno = nilfs->ns_last_cno + 1;
197 if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
198 printk(KERN_ERR "NILFS invalid last segment number.\n");
199 ret = -EINVAL;
200 }
201 return ret;
202}
203
204
205
206
207
208
209
210
211
212
213int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
214{
215 struct nilfs_recovery_info ri;
216 unsigned int s_flags = sb->s_flags;
217 int really_read_only = bdev_read_only(nilfs->ns_bdev);
218 int valid_fs = nilfs_valid_fs(nilfs);
219 int err;
220
221 if (!valid_fs) {
222 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
223 if (s_flags & MS_RDONLY) {
224 printk(KERN_INFO "NILFS: INFO: recovery "
225 "required for readonly filesystem.\n");
226 printk(KERN_INFO "NILFS: write access will "
227 "be enabled during recovery.\n");
228 }
229 }
230
231 nilfs_init_recovery_info(&ri);
232
233 err = nilfs_search_super_root(nilfs, &ri);
234 if (unlikely(err)) {
235 struct nilfs_super_block **sbp = nilfs->ns_sbp;
236 int blocksize;
237
238 if (err != -EINVAL)
239 goto scan_error;
240
241 if (!nilfs_valid_sb(sbp[1])) {
242 printk(KERN_WARNING
243 "NILFS warning: unable to fall back to spare"
244 "super block\n");
245 goto scan_error;
246 }
247 printk(KERN_INFO
248 "NILFS: try rollback from an earlier position\n");
249
250
251
252
253
254 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
255 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
256 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
257
258
259 blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
260 if (blocksize != nilfs->ns_blocksize) {
261 printk(KERN_WARNING
262 "NILFS warning: blocksize differs between "
263 "two super blocks (%d != %d)\n",
264 blocksize, nilfs->ns_blocksize);
265 goto scan_error;
266 }
267
268 err = nilfs_store_log_cursor(nilfs, sbp[0]);
269 if (err)
270 goto scan_error;
271
272
273 nilfs->ns_mount_state &= ~NILFS_VALID_FS;
274 valid_fs = 0;
275
276 err = nilfs_search_super_root(nilfs, &ri);
277 if (err)
278 goto scan_error;
279 }
280
281 err = nilfs_load_super_root(nilfs, sb, ri.ri_super_root);
282 if (unlikely(err)) {
283 printk(KERN_ERR "NILFS: error loading super root.\n");
284 goto failed;
285 }
286
287 if (valid_fs)
288 goto skip_recovery;
289
290 if (s_flags & MS_RDONLY) {
291 __u64 features;
292
293 if (nilfs_test_opt(nilfs, NORECOVERY)) {
294 printk(KERN_INFO "NILFS: norecovery option specified. "
295 "skipping roll-forward recovery\n");
296 goto skip_recovery;
297 }
298 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
299 ~NILFS_FEATURE_COMPAT_RO_SUPP;
300 if (features) {
301 printk(KERN_ERR "NILFS: couldn't proceed with "
302 "recovery because of unsupported optional "
303 "features (%llx)\n",
304 (unsigned long long)features);
305 err = -EROFS;
306 goto failed_unload;
307 }
308 if (really_read_only) {
309 printk(KERN_ERR "NILFS: write access "
310 "unavailable, cannot proceed.\n");
311 err = -EROFS;
312 goto failed_unload;
313 }
314 sb->s_flags &= ~MS_RDONLY;
315 } else if (nilfs_test_opt(nilfs, NORECOVERY)) {
316 printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
317 "option was specified for a read/write mount\n");
318 err = -EINVAL;
319 goto failed_unload;
320 }
321
322 err = nilfs_salvage_orphan_logs(nilfs, sb, &ri);
323 if (err)
324 goto failed_unload;
325
326 down_write(&nilfs->ns_sem);
327 nilfs->ns_mount_state |= NILFS_VALID_FS;
328 err = nilfs_cleanup_super(sb);
329 up_write(&nilfs->ns_sem);
330
331 if (err) {
332 printk(KERN_ERR "NILFS: failed to update super block. "
333 "recovery unfinished.\n");
334 goto failed_unload;
335 }
336 printk(KERN_INFO "NILFS: recovery complete.\n");
337
338 skip_recovery:
339 nilfs_clear_recovery_info(&ri);
340 sb->s_flags = s_flags;
341 return 0;
342
343 scan_error:
344 printk(KERN_ERR "NILFS: error searching super root.\n");
345 goto failed;
346
347 failed_unload:
348 iput(nilfs->ns_cpfile);
349 iput(nilfs->ns_sufile);
350 iput(nilfs->ns_dat);
351
352 failed:
353 nilfs_clear_recovery_info(&ri);
354 sb->s_flags = s_flags;
355 return err;
356}
357
358static unsigned long long nilfs_max_size(unsigned int blkbits)
359{
360 unsigned int max_bits;
361 unsigned long long res = MAX_LFS_FILESIZE;
362
363 max_bits = blkbits + NILFS_BMAP_KEY_BIT;
364 if (max_bits < 64)
365 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
366 return res;
367}
368
369
370
371
372
373
374unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
375{
376 return max_t(unsigned long, NILFS_MIN_NRSVSEGS,
377 DIV_ROUND_UP(nsegs * nilfs->ns_r_segments_percentage,
378 100));
379}
380
381void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs)
382{
383 nilfs->ns_nsegments = nsegs;
384 nilfs->ns_nrsvsegs = nilfs_nrsvsegs(nilfs, nsegs);
385}
386
387static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
388 struct nilfs_super_block *sbp)
389{
390 if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
391 printk(KERN_ERR "NILFS: unsupported revision "
392 "(superblock rev.=%d.%d, current rev.=%d.%d). "
393 "Please check the version of mkfs.nilfs.\n",
394 le32_to_cpu(sbp->s_rev_level),
395 le16_to_cpu(sbp->s_minor_rev_level),
396 NILFS_CURRENT_REV, NILFS_MINOR_REV);
397 return -EINVAL;
398 }
399 nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
400 if (nilfs->ns_sbsize > BLOCK_SIZE)
401 return -EINVAL;
402
403 nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
404 if (nilfs->ns_inode_size > nilfs->ns_blocksize) {
405 printk(KERN_ERR "NILFS: too large inode size: %d bytes.\n",
406 nilfs->ns_inode_size);
407 return -EINVAL;
408 } else if (nilfs->ns_inode_size < NILFS_MIN_INODE_SIZE) {
409 printk(KERN_ERR "NILFS: too small inode size: %d bytes.\n",
410 nilfs->ns_inode_size);
411 return -EINVAL;
412 }
413
414 nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
415
416 nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
417 if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
418 printk(KERN_ERR "NILFS: too short segment.\n");
419 return -EINVAL;
420 }
421
422 nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
423 nilfs->ns_r_segments_percentage =
424 le32_to_cpu(sbp->s_r_segments_percentage);
425 if (nilfs->ns_r_segments_percentage < 1 ||
426 nilfs->ns_r_segments_percentage > 99) {
427 printk(KERN_ERR "NILFS: invalid reserved segments percentage.\n");
428 return -EINVAL;
429 }
430
431 nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments));
432 nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
433 return 0;
434}
435
436static int nilfs_valid_sb(struct nilfs_super_block *sbp)
437{
438 static unsigned char sum[4];
439 const int sumoff = offsetof(struct nilfs_super_block, s_sum);
440 size_t bytes;
441 u32 crc;
442
443 if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
444 return 0;
445 bytes = le16_to_cpu(sbp->s_bytes);
446 if (bytes > BLOCK_SIZE)
447 return 0;
448 crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
449 sumoff);
450 crc = crc32_le(crc, sum, 4);
451 crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
452 bytes - sumoff - 4);
453 return crc == le32_to_cpu(sbp->s_sum);
454}
455
456static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
457{
458 return offset < ((le64_to_cpu(sbp->s_nsegments) *
459 le32_to_cpu(sbp->s_blocks_per_segment)) <<
460 (le32_to_cpu(sbp->s_log_block_size) + 10));
461}
462
463static void nilfs_release_super_block(struct the_nilfs *nilfs)
464{
465 int i;
466
467 for (i = 0; i < 2; i++) {
468 if (nilfs->ns_sbp[i]) {
469 brelse(nilfs->ns_sbh[i]);
470 nilfs->ns_sbh[i] = NULL;
471 nilfs->ns_sbp[i] = NULL;
472 }
473 }
474}
475
476void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
477{
478 brelse(nilfs->ns_sbh[0]);
479 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
480 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
481 nilfs->ns_sbh[1] = NULL;
482 nilfs->ns_sbp[1] = NULL;
483}
484
485void nilfs_swap_super_block(struct the_nilfs *nilfs)
486{
487 struct buffer_head *tsbh = nilfs->ns_sbh[0];
488 struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
489
490 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
491 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
492 nilfs->ns_sbh[1] = tsbh;
493 nilfs->ns_sbp[1] = tsbp;
494}
495
496static int nilfs_load_super_block(struct the_nilfs *nilfs,
497 struct super_block *sb, int blocksize,
498 struct nilfs_super_block **sbpp)
499{
500 struct nilfs_super_block **sbp = nilfs->ns_sbp;
501 struct buffer_head **sbh = nilfs->ns_sbh;
502 u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
503 int valid[2], swp = 0;
504
505 sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
506 &sbh[0]);
507 sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
508
509 if (!sbp[0]) {
510 if (!sbp[1]) {
511 printk(KERN_ERR "NILFS: unable to read superblock\n");
512 return -EIO;
513 }
514 printk(KERN_WARNING
515 "NILFS warning: unable to read primary superblock "
516 "(blocksize = %d)\n", blocksize);
517 } else if (!sbp[1]) {
518 printk(KERN_WARNING
519 "NILFS warning: unable to read secondary superblock "
520 "(blocksize = %d)\n", blocksize);
521 }
522
523
524
525
526
527 valid[0] = nilfs_valid_sb(sbp[0]);
528 valid[1] = nilfs_valid_sb(sbp[1]);
529 swp = valid[1] && (!valid[0] ||
530 le64_to_cpu(sbp[1]->s_last_cno) >
531 le64_to_cpu(sbp[0]->s_last_cno));
532
533 if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
534 brelse(sbh[1]);
535 sbh[1] = NULL;
536 sbp[1] = NULL;
537 valid[1] = 0;
538 swp = 0;
539 }
540 if (!valid[swp]) {
541 nilfs_release_super_block(nilfs);
542 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
543 sb->s_id);
544 return -EINVAL;
545 }
546
547 if (!valid[!swp])
548 printk(KERN_WARNING "NILFS warning: broken superblock. "
549 "using spare superblock (blocksize = %d).\n", blocksize);
550 if (swp)
551 nilfs_swap_super_block(nilfs);
552
553 nilfs->ns_sbwcount = 0;
554 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
555 nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
556 *sbpp = sbp[0];
557 return 0;
558}
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
574{
575 struct nilfs_super_block *sbp;
576 int blocksize;
577 int err;
578
579 down_write(&nilfs->ns_sem);
580
581 blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
582 if (!blocksize) {
583 printk(KERN_ERR "NILFS: unable to set blocksize\n");
584 err = -EINVAL;
585 goto out;
586 }
587 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
588 if (err)
589 goto out;
590
591 err = nilfs_store_magic_and_option(sb, sbp, data);
592 if (err)
593 goto failed_sbh;
594
595 err = nilfs_check_feature_compatibility(sb, sbp);
596 if (err)
597 goto failed_sbh;
598
599 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
600 if (blocksize < NILFS_MIN_BLOCK_SIZE ||
601 blocksize > NILFS_MAX_BLOCK_SIZE) {
602 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
603 "filesystem blocksize %d\n", blocksize);
604 err = -EINVAL;
605 goto failed_sbh;
606 }
607 if (sb->s_blocksize != blocksize) {
608 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
609
610 if (blocksize < hw_blocksize) {
611 printk(KERN_ERR
612 "NILFS: blocksize %d too small for device "
613 "(sector-size = %d).\n",
614 blocksize, hw_blocksize);
615 err = -EINVAL;
616 goto failed_sbh;
617 }
618 nilfs_release_super_block(nilfs);
619 sb_set_blocksize(sb, blocksize);
620
621 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
622 if (err)
623 goto out;
624
625
626 }
627 nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
628 nilfs->ns_blocksize = blocksize;
629
630 get_random_bytes(&nilfs->ns_next_generation,
631 sizeof(nilfs->ns_next_generation));
632
633 err = nilfs_store_disk_layout(nilfs, sbp);
634 if (err)
635 goto failed_sbh;
636
637 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
638
639 nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
640
641 err = nilfs_store_log_cursor(nilfs, sbp);
642 if (err)
643 goto failed_sbh;
644
645 err = nilfs_sysfs_create_device_group(sb);
646 if (err)
647 goto failed_sbh;
648
649 set_nilfs_init(nilfs);
650 err = 0;
651 out:
652 up_write(&nilfs->ns_sem);
653 return err;
654
655 failed_sbh:
656 nilfs_release_super_block(nilfs);
657 goto out;
658}
659
660int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
661 size_t nsegs)
662{
663 sector_t seg_start, seg_end;
664 sector_t start = 0, nblocks = 0;
665 unsigned int sects_per_block;
666 __u64 *sn;
667 int ret = 0;
668
669 sects_per_block = (1 << nilfs->ns_blocksize_bits) /
670 bdev_logical_block_size(nilfs->ns_bdev);
671 for (sn = segnump; sn < segnump + nsegs; sn++) {
672 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
673
674 if (!nblocks) {
675 start = seg_start;
676 nblocks = seg_end - seg_start + 1;
677 } else if (start + nblocks == seg_start) {
678 nblocks += seg_end - seg_start + 1;
679 } else {
680 ret = blkdev_issue_discard(nilfs->ns_bdev,
681 start * sects_per_block,
682 nblocks * sects_per_block,
683 GFP_NOFS, 0);
684 if (ret < 0)
685 return ret;
686 nblocks = 0;
687 }
688 }
689 if (nblocks)
690 ret = blkdev_issue_discard(nilfs->ns_bdev,
691 start * sects_per_block,
692 nblocks * sects_per_block,
693 GFP_NOFS, 0);
694 return ret;
695}
696
697int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
698{
699 unsigned long ncleansegs;
700
701 down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
702 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
703 up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
704 *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
705 return 0;
706}
707
708int nilfs_near_disk_full(struct the_nilfs *nilfs)
709{
710 unsigned long ncleansegs, nincsegs;
711
712 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
713 nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
714 nilfs->ns_blocks_per_segment + 1;
715
716 return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
717}
718
719struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
720{
721 struct rb_node *n;
722 struct nilfs_root *root;
723
724 spin_lock(&nilfs->ns_cptree_lock);
725 n = nilfs->ns_cptree.rb_node;
726 while (n) {
727 root = rb_entry(n, struct nilfs_root, rb_node);
728
729 if (cno < root->cno) {
730 n = n->rb_left;
731 } else if (cno > root->cno) {
732 n = n->rb_right;
733 } else {
734 atomic_inc(&root->count);
735 spin_unlock(&nilfs->ns_cptree_lock);
736 return root;
737 }
738 }
739 spin_unlock(&nilfs->ns_cptree_lock);
740
741 return NULL;
742}
743
744struct nilfs_root *
745nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
746{
747 struct rb_node **p, *parent;
748 struct nilfs_root *root, *new;
749 int err;
750
751 root = nilfs_lookup_root(nilfs, cno);
752 if (root)
753 return root;
754
755 new = kzalloc(sizeof(*root), GFP_KERNEL);
756 if (!new)
757 return NULL;
758
759 spin_lock(&nilfs->ns_cptree_lock);
760
761 p = &nilfs->ns_cptree.rb_node;
762 parent = NULL;
763
764 while (*p) {
765 parent = *p;
766 root = rb_entry(parent, struct nilfs_root, rb_node);
767
768 if (cno < root->cno) {
769 p = &(*p)->rb_left;
770 } else if (cno > root->cno) {
771 p = &(*p)->rb_right;
772 } else {
773 atomic_inc(&root->count);
774 spin_unlock(&nilfs->ns_cptree_lock);
775 kfree(new);
776 return root;
777 }
778 }
779
780 new->cno = cno;
781 new->ifile = NULL;
782 new->nilfs = nilfs;
783 atomic_set(&new->count, 1);
784 atomic64_set(&new->inodes_count, 0);
785 atomic64_set(&new->blocks_count, 0);
786
787 rb_link_node(&new->rb_node, parent, p);
788 rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
789
790 spin_unlock(&nilfs->ns_cptree_lock);
791
792 err = nilfs_sysfs_create_snapshot_group(new);
793 if (err) {
794 kfree(new);
795 new = NULL;
796 }
797
798 return new;
799}
800
801void nilfs_put_root(struct nilfs_root *root)
802{
803 if (atomic_dec_and_test(&root->count)) {
804 struct the_nilfs *nilfs = root->nilfs;
805
806 nilfs_sysfs_delete_snapshot_group(root);
807
808 spin_lock(&nilfs->ns_cptree_lock);
809 rb_erase(&root->rb_node, &nilfs->ns_cptree);
810 spin_unlock(&nilfs->ns_cptree_lock);
811 iput(root->ifile);
812
813 kfree(root);
814 }
815}
816
