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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
89 return nilfs;
90}
91
92
93
94
95
96void 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
106static 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
160static 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
166static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
167{
168 nilfs_dispose_segment_list(&ri->ri_used_segments);
169}
170
171
172
173
174
175
176
177
178
179
180
181static 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
204
205
206
207
208
209
210
211int 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
250
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
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
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;
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
356static unsigned long long nilfs_max_size(unsigned int blkbits)
357{
358 unsigned int max_bits;
359 unsigned long long res = MAX_LFS_FILESIZE;
360
361 max_bits = blkbits + NILFS_BMAP_KEY_BIT;
362 if (max_bits < 64)
363 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
364 return res;
365}
366
367
368
369
370
371
372unsigned 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
379void 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
385static 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 if (nilfs->ns_r_segments_percentage < 1 ||
414 nilfs->ns_r_segments_percentage > 99) {
415 printk(KERN_ERR "NILFS: invalid reserved segments percentage.\n");
416 return -EINVAL;
417 }
418
419 nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments));
420 nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
421 return 0;
422}
423
424static int nilfs_valid_sb(struct nilfs_super_block *sbp)
425{
426 static unsigned char sum[4];
427 const int sumoff = offsetof(struct nilfs_super_block, s_sum);
428 size_t bytes;
429 u32 crc;
430
431 if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
432 return 0;
433 bytes = le16_to_cpu(sbp->s_bytes);
434 if (bytes > BLOCK_SIZE)
435 return 0;
436 crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
437 sumoff);
438 crc = crc32_le(crc, sum, 4);
439 crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
440 bytes - sumoff - 4);
441 return crc == le32_to_cpu(sbp->s_sum);
442}
443
444static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
445{
446 return offset < ((le64_to_cpu(sbp->s_nsegments) *
447 le32_to_cpu(sbp->s_blocks_per_segment)) <<
448 (le32_to_cpu(sbp->s_log_block_size) + 10));
449}
450
451static void nilfs_release_super_block(struct the_nilfs *nilfs)
452{
453 int i;
454
455 for (i = 0; i < 2; i++) {
456 if (nilfs->ns_sbp[i]) {
457 brelse(nilfs->ns_sbh[i]);
458 nilfs->ns_sbh[i] = NULL;
459 nilfs->ns_sbp[i] = NULL;
460 }
461 }
462}
463
464void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
465{
466 brelse(nilfs->ns_sbh[0]);
467 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
468 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
469 nilfs->ns_sbh[1] = NULL;
470 nilfs->ns_sbp[1] = NULL;
471}
472
473void nilfs_swap_super_block(struct the_nilfs *nilfs)
474{
475 struct buffer_head *tsbh = nilfs->ns_sbh[0];
476 struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
477
478 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
479 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
480 nilfs->ns_sbh[1] = tsbh;
481 nilfs->ns_sbp[1] = tsbp;
482}
483
484static int nilfs_load_super_block(struct the_nilfs *nilfs,
485 struct super_block *sb, int blocksize,
486 struct nilfs_super_block **sbpp)
487{
488 struct nilfs_super_block **sbp = nilfs->ns_sbp;
489 struct buffer_head **sbh = nilfs->ns_sbh;
490 u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
491 int valid[2], swp = 0;
492
493 sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
494 &sbh[0]);
495 sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
496
497 if (!sbp[0]) {
498 if (!sbp[1]) {
499 printk(KERN_ERR "NILFS: unable to read superblock\n");
500 return -EIO;
501 }
502 printk(KERN_WARNING
503 "NILFS warning: unable to read primary superblock "
504 "(blocksize = %d)\n", blocksize);
505 } else if (!sbp[1]) {
506 printk(KERN_WARNING
507 "NILFS warning: unable to read secondary superblock "
508 "(blocksize = %d)\n", blocksize);
509 }
510
511
512
513
514
515 valid[0] = nilfs_valid_sb(sbp[0]);
516 valid[1] = nilfs_valid_sb(sbp[1]);
517 swp = valid[1] && (!valid[0] ||
518 le64_to_cpu(sbp[1]->s_last_cno) >
519 le64_to_cpu(sbp[0]->s_last_cno));
520
521 if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
522 brelse(sbh[1]);
523 sbh[1] = NULL;
524 sbp[1] = NULL;
525 valid[1] = 0;
526 swp = 0;
527 }
528 if (!valid[swp]) {
529 nilfs_release_super_block(nilfs);
530 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
531 sb->s_id);
532 return -EINVAL;
533 }
534
535 if (!valid[!swp])
536 printk(KERN_WARNING "NILFS warning: broken superblock. "
537 "using spare superblock (blocksize = %d).\n", blocksize);
538 if (swp)
539 nilfs_swap_super_block(nilfs);
540
541 nilfs->ns_sbwcount = 0;
542 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
543 nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
544 *sbpp = sbp[0];
545 return 0;
546}
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
562{
563 struct nilfs_super_block *sbp;
564 int blocksize;
565 int err;
566
567 down_write(&nilfs->ns_sem);
568
569 blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
570 if (!blocksize) {
571 printk(KERN_ERR "NILFS: unable to set blocksize\n");
572 err = -EINVAL;
573 goto out;
574 }
575 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
576 if (err)
577 goto out;
578
579 err = nilfs_store_magic_and_option(sb, sbp, data);
580 if (err)
581 goto failed_sbh;
582
583 err = nilfs_check_feature_compatibility(sb, sbp);
584 if (err)
585 goto failed_sbh;
586
587 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
588 if (blocksize < NILFS_MIN_BLOCK_SIZE ||
589 blocksize > NILFS_MAX_BLOCK_SIZE) {
590 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
591 "filesystem blocksize %d\n", blocksize);
592 err = -EINVAL;
593 goto failed_sbh;
594 }
595 if (sb->s_blocksize != blocksize) {
596 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
597
598 if (blocksize < hw_blocksize) {
599 printk(KERN_ERR
600 "NILFS: blocksize %d too small for device "
601 "(sector-size = %d).\n",
602 blocksize, hw_blocksize);
603 err = -EINVAL;
604 goto failed_sbh;
605 }
606 nilfs_release_super_block(nilfs);
607 sb_set_blocksize(sb, blocksize);
608
609 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
610 if (err)
611 goto out;
612
613
614 }
615 nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
616 nilfs->ns_blocksize = blocksize;
617
618 get_random_bytes(&nilfs->ns_next_generation,
619 sizeof(nilfs->ns_next_generation));
620
621 err = nilfs_store_disk_layout(nilfs, sbp);
622 if (err)
623 goto failed_sbh;
624
625 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
626
627 nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
628
629 err = nilfs_store_log_cursor(nilfs, sbp);
630 if (err)
631 goto failed_sbh;
632
633 set_nilfs_init(nilfs);
634 err = 0;
635 out:
636 up_write(&nilfs->ns_sem);
637 return err;
638
639 failed_sbh:
640 nilfs_release_super_block(nilfs);
641 goto out;
642}
643
644int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
645 size_t nsegs)
646{
647 sector_t seg_start, seg_end;
648 sector_t start = 0, nblocks = 0;
649 unsigned int sects_per_block;
650 __u64 *sn;
651 int ret = 0;
652
653 sects_per_block = (1 << nilfs->ns_blocksize_bits) /
654 bdev_logical_block_size(nilfs->ns_bdev);
655 for (sn = segnump; sn < segnump + nsegs; sn++) {
656 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
657
658 if (!nblocks) {
659 start = seg_start;
660 nblocks = seg_end - seg_start + 1;
661 } else if (start + nblocks == seg_start) {
662 nblocks += seg_end - seg_start + 1;
663 } else {
664 ret = blkdev_issue_discard(nilfs->ns_bdev,
665 start * sects_per_block,
666 nblocks * sects_per_block,
667 GFP_NOFS, 0);
668 if (ret < 0)
669 return ret;
670 nblocks = 0;
671 }
672 }
673 if (nblocks)
674 ret = blkdev_issue_discard(nilfs->ns_bdev,
675 start * sects_per_block,
676 nblocks * sects_per_block,
677 GFP_NOFS, 0);
678 return ret;
679}
680
681int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
682{
683 unsigned long ncleansegs;
684
685 down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
686 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
687 up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
688 *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
689 return 0;
690}
691
692int nilfs_near_disk_full(struct the_nilfs *nilfs)
693{
694 unsigned long ncleansegs, nincsegs;
695
696 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
697 nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
698 nilfs->ns_blocks_per_segment + 1;
699
700 return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
701}
702
703struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
704{
705 struct rb_node *n;
706 struct nilfs_root *root;
707
708 spin_lock(&nilfs->ns_cptree_lock);
709 n = nilfs->ns_cptree.rb_node;
710 while (n) {
711 root = rb_entry(n, struct nilfs_root, rb_node);
712
713 if (cno < root->cno) {
714 n = n->rb_left;
715 } else if (cno > root->cno) {
716 n = n->rb_right;
717 } else {
718 atomic_inc(&root->count);
719 spin_unlock(&nilfs->ns_cptree_lock);
720 return root;
721 }
722 }
723 spin_unlock(&nilfs->ns_cptree_lock);
724
725 return NULL;
726}
727
728struct nilfs_root *
729nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
730{
731 struct rb_node **p, *parent;
732 struct nilfs_root *root, *new;
733
734 root = nilfs_lookup_root(nilfs, cno);
735 if (root)
736 return root;
737
738 new = kmalloc(sizeof(*root), GFP_KERNEL);
739 if (!new)
740 return NULL;
741
742 spin_lock(&nilfs->ns_cptree_lock);
743
744 p = &nilfs->ns_cptree.rb_node;
745 parent = NULL;
746
747 while (*p) {
748 parent = *p;
749 root = rb_entry(parent, struct nilfs_root, rb_node);
750
751 if (cno < root->cno) {
752 p = &(*p)->rb_left;
753 } else if (cno > root->cno) {
754 p = &(*p)->rb_right;
755 } else {
756 atomic_inc(&root->count);
757 spin_unlock(&nilfs->ns_cptree_lock);
758 kfree(new);
759 return root;
760 }
761 }
762
763 new->cno = cno;
764 new->ifile = NULL;
765 new->nilfs = nilfs;
766 atomic_set(&new->count, 1);
767 atomic_set(&new->inodes_count, 0);
768 atomic_set(&new->blocks_count, 0);
769
770 rb_link_node(&new->rb_node, parent, p);
771 rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
772
773 spin_unlock(&nilfs->ns_cptree_lock);
774
775 return new;
776}
777
778void nilfs_put_root(struct nilfs_root *root)
779{
780 if (atomic_dec_and_test(&root->count)) {
781 struct the_nilfs *nilfs = root->nilfs;
782
783 spin_lock(&nilfs->ns_cptree_lock);
784 rb_erase(&root->rb_node, &nilfs->ns_cptree);
785 spin_unlock(&nilfs->ns_cptree_lock);
786 if (root->ifile)
787 iput(root->ifile);
788
789 kfree(root);
790 }
791}
792
