1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * the_nilfs shared structure.
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Written by Ryusuke Konishi.
8 *
9 */
10
11 #include <linux/buffer_head.h>
12 #include <linux/slab.h>
13 #include <linux/blkdev.h>
14 #include <linux/backing-dev.h>
15 #include <linux/random.h>
16 #include <linux/log2.h>
17 #include <linux/crc32.h>
18 #include "nilfs.h"
19 #include "segment.h"
20 #include "alloc.h"
21 #include "cpfile.h"
22 #include "sufile.h"
23 #include "dat.h"
24 #include "segbuf.h"
25
26
27 static int nilfs_valid_sb(struct nilfs_super_block *sbp);
28
29 void nilfs_set_last_segment(struct the_nilfs *nilfs,
30 sector_t start_blocknr, u64 seq, __u64 cno)
31 {
32 spin_lock(&nilfs->ns_last_segment_lock);
33 nilfs->ns_last_pseg = start_blocknr;
34 nilfs->ns_last_seq = seq;
35 nilfs->ns_last_cno = cno;
36
37 if (!nilfs_sb_dirty(nilfs)) {
38 if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
39 goto stay_cursor;
40
41 set_nilfs_sb_dirty(nilfs);
42 }
43 nilfs->ns_prev_seq = nilfs->ns_last_seq;
44
45 stay_cursor:
46 spin_unlock(&nilfs->ns_last_segment_lock);
47 }
48
49 /**
50 * alloc_nilfs - allocate a nilfs object
51 * @sb: super block instance
52 *
53 * Return Value: On success, pointer to the_nilfs is returned.
54 * On error, NULL is returned.
55 */
56 struct the_nilfs *alloc_nilfs(struct super_block *sb)
57 {
58 struct the_nilfs *nilfs;
59
60 nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
61 if (!nilfs)
62 return NULL;
63
64 nilfs->ns_sb = sb;
65 nilfs->ns_bdev = sb->s_bdev;
66 atomic_set(&nilfs->ns_ndirtyblks, 0);
67 init_rwsem(&nilfs->ns_sem);
68 mutex_init(&nilfs->ns_snapshot_mount_mutex);
69 INIT_LIST_HEAD(&nilfs->ns_dirty_files);
70 INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
71 spin_lock_init(&nilfs->ns_inode_lock);
72 spin_lock_init(&nilfs->ns_next_gen_lock);
73 spin_lock_init(&nilfs->ns_last_segment_lock);
74 nilfs->ns_cptree = RB_ROOT;
75 spin_lock_init(&nilfs->ns_cptree_lock);
76 init_rwsem(&nilfs->ns_segctor_sem);
77 nilfs->ns_sb_update_freq = NILFS_SB_FREQ;
78
79 return nilfs;
80 }
81
82 /**
83 * destroy_nilfs - destroy nilfs object
84 * @nilfs: nilfs object to be released
85 */
86 void destroy_nilfs(struct the_nilfs *nilfs)
87 {
88 might_sleep();
89 if (nilfs_init(nilfs)) {
90 brelse(nilfs->ns_sbh[0]);
91 brelse(nilfs->ns_sbh[1]);
92 }
93 kfree(nilfs);
94 }
95
96 static int nilfs_load_super_root(struct the_nilfs *nilfs,
97 struct super_block *sb, sector_t sr_block)
98 {
99 struct buffer_head *bh_sr;
100 struct nilfs_super_root *raw_sr;
101 struct nilfs_super_block **sbp = nilfs->ns_sbp;
102 struct nilfs_inode *rawi;
103 unsigned int dat_entry_size, segment_usage_size, checkpoint_size;
104 unsigned int inode_size;
105 int err;
106
107 err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
108 if (unlikely(err))
109 return err;
110
111 down_read(&nilfs->ns_sem);
112 dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
113 checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
114 segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
115 up_read(&nilfs->ns_sem);
116
117 inode_size = nilfs->ns_inode_size;
118
119 rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
120 err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
121 if (err)
122 goto failed;
123
124 rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
125 err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
126 if (err)
127 goto failed_dat;
128
129 rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
130 err = nilfs_sufile_read(sb, segment_usage_size, rawi,
131 &nilfs->ns_sufile);
132 if (err)
133 goto failed_cpfile;
134
135 raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
136 nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
137
138 failed:
139 brelse(bh_sr);
140 return err;
141
142 failed_cpfile:
143 iput(nilfs->ns_cpfile);
144
145 failed_dat:
146 iput(nilfs->ns_dat);
147 goto failed;
148 }
149
150 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
151 {
152 memset(ri, 0, sizeof(*ri));
153 INIT_LIST_HEAD(&ri->ri_used_segments);
154 }
155
156 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
157 {
158 nilfs_dispose_segment_list(&ri->ri_used_segments);
159 }
160
161 /**
162 * nilfs_store_log_cursor - load log cursor from a super block
163 * @nilfs: nilfs object
164 * @sbp: buffer storing super block to be read
165 *
166 * nilfs_store_log_cursor() reads the last position of the log
167 * containing a super root from a given super block, and initializes
168 * relevant information on the nilfs object preparatory for log
169 * scanning and recovery.
170 */
171 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
172 struct nilfs_super_block *sbp)
173 {
174 int ret = 0;
175
176 nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
177 nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
178 nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
179
180 nilfs->ns_prev_seq = nilfs->ns_last_seq;
181 nilfs->ns_seg_seq = nilfs->ns_last_seq;
182 nilfs->ns_segnum =
183 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
184 nilfs->ns_cno = nilfs->ns_last_cno + 1;
185 if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
186 nilfs_err(nilfs->ns_sb,
187 "pointed segment number is out of range: segnum=%llu, nsegments=%lu",
188 (unsigned long long)nilfs->ns_segnum,
189 nilfs->ns_nsegments);
190 ret = -EINVAL;
191 }
192 return ret;
193 }
194
195 /**
196 * nilfs_get_blocksize - get block size from raw superblock data
197 * @sb: super block instance
198 * @sbp: superblock raw data buffer
199 * @blocksize: place to store block size
200 *
201 * nilfs_get_blocksize() calculates the block size from the block size
202 * exponent information written in @sbp and stores it in @blocksize,
203 * or aborts with an error message if it's too large.
204 *
205 * Return Value: On success, 0 is returned. If the block size is too
206 * large, -EINVAL is returned.
207 */
208 static int nilfs_get_blocksize(struct super_block *sb,
209 struct nilfs_super_block *sbp, int *blocksize)
210 {
211 unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
212
213 if (unlikely(shift_bits >
214 ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)) {
215 nilfs_err(sb, "too large filesystem blocksize: 2 ^ %u KiB",
216 shift_bits);
217 return -EINVAL;
218 }
219 *blocksize = BLOCK_SIZE << shift_bits;
220 return 0;
221 }
222
223 /**
224 * load_nilfs - load and recover the nilfs
225 * @nilfs: the_nilfs structure to be released
226 * @sb: super block instance used to recover past segment
227 *
228 * load_nilfs() searches and load the latest super root,
229 * attaches the last segment, and does recovery if needed.
230 * The caller must call this exclusively for simultaneous mounts.
231 */
232 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
233 {
234 struct nilfs_recovery_info ri;
235 unsigned int s_flags = sb->s_flags;
236 int really_read_only = bdev_read_only(nilfs->ns_bdev);
237 int valid_fs = nilfs_valid_fs(nilfs);
238 int err;
239
240 if (!valid_fs) {
241 nilfs_warn(sb, "mounting unchecked fs");
242 if (s_flags & SB_RDONLY) {
243 nilfs_info(sb,
244 "recovery required for readonly filesystem");
245 nilfs_info(sb,
246 "write access will be enabled during recovery");
247 }
248 }
249
250 nilfs_init_recovery_info(&ri);
251
252 err = nilfs_search_super_root(nilfs, &ri);
253 if (unlikely(err)) {
254 struct nilfs_super_block **sbp = nilfs->ns_sbp;
255 int blocksize;
256
257 if (err != -EINVAL)
258 goto scan_error;
259
260 if (!nilfs_valid_sb(sbp[1])) {
261 nilfs_warn(sb,
262 "unable to fall back to spare super block");
263 goto scan_error;
264 }
265 nilfs_info(sb, "trying rollback from an earlier position");
266
267 /*
268 * restore super block with its spare and reconfigure
269 * relevant states of the nilfs object.
270 */
271 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
272 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
273 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
274
275 /* verify consistency between two super blocks */
276 err = nilfs_get_blocksize(sb, sbp[0], &blocksize);
277 if (err)
278 goto scan_error;
279
280 if (blocksize != nilfs->ns_blocksize) {
281 nilfs_warn(sb,
282 "blocksize differs between two super blocks (%d != %d)",
283 blocksize, nilfs->ns_blocksize);
284 err = -EINVAL;
285 goto scan_error;
286 }
287
288 err = nilfs_store_log_cursor(nilfs, sbp[0]);
289 if (err)
290 goto scan_error;
291
292 /* drop clean flag to allow roll-forward and recovery */
293 nilfs->ns_mount_state &= ~NILFS_VALID_FS;
294 valid_fs = 0;
295
296 err = nilfs_search_super_root(nilfs, &ri);
297 if (err)
298 goto scan_error;
299 }
300
301 err = nilfs_load_super_root(nilfs, sb, ri.ri_super_root);
302 if (unlikely(err)) {
303 nilfs_err(sb, "error %d while loading super root", err);
304 goto failed;
305 }
306
307 err = nilfs_sysfs_create_device_group(sb);
308 if (unlikely(err))
309 goto sysfs_error;
310
311 if (valid_fs)
312 goto skip_recovery;
313
314 if (s_flags & SB_RDONLY) {
315 __u64 features;
316
317 if (nilfs_test_opt(nilfs, NORECOVERY)) {
318 nilfs_info(sb,
319 "norecovery option specified, skipping roll-forward recovery");
320 goto skip_recovery;
321 }
322 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
323 ~NILFS_FEATURE_COMPAT_RO_SUPP;
324 if (features) {
325 nilfs_err(sb,
326 "couldn't proceed with recovery because of unsupported optional features (%llx)",
327 (unsigned long long)features);
328 err = -EROFS;
329 goto failed_unload;
330 }
331 if (really_read_only) {
332 nilfs_err(sb,
333 "write access unavailable, cannot proceed");
334 err = -EROFS;
335 goto failed_unload;
336 }
337 sb->s_flags &= ~SB_RDONLY;
338 } else if (nilfs_test_opt(nilfs, NORECOVERY)) {
339 nilfs_err(sb,
340 "recovery cancelled because norecovery option was specified for a read/write mount");
341 err = -EINVAL;
342 goto failed_unload;
343 }
344
345 err = nilfs_salvage_orphan_logs(nilfs, sb, &ri);
346 if (err)
347 goto failed_unload;
348
349 down_write(&nilfs->ns_sem);
350 nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
351 err = nilfs_cleanup_super(sb);
352 up_write(&nilfs->ns_sem);
353
354 if (err) {
355 nilfs_err(sb,
356 "error %d updating super block. recovery unfinished.",
357 err);
358 goto failed_unload;
359 }
360 nilfs_info(sb, "recovery complete");
361
362 skip_recovery:
363 nilfs_clear_recovery_info(&ri);
364 sb->s_flags = s_flags;
365 return 0;
366
367 scan_error:
368 nilfs_err(sb, "error %d while searching super root", err);
369 goto failed;
370
371 failed_unload:
372 nilfs_sysfs_delete_device_group(nilfs);
373
374 sysfs_error:
375 iput(nilfs->ns_cpfile);
376 iput(nilfs->ns_sufile);
377 iput(nilfs->ns_dat);
378
379 failed:
380 nilfs_clear_recovery_info(&ri);
381 sb->s_flags = s_flags;
382 return err;
383 }
384
385 static unsigned long long nilfs_max_size(unsigned int blkbits)
386 {
387 unsigned int max_bits;
388 unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
389
390 max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
391 if (max_bits < 64)
392 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
393 return res;
394 }
395
396 /**
397 * nilfs_nrsvsegs - calculate the number of reserved segments
398 * @nilfs: nilfs object
399 * @nsegs: total number of segments
400 */
401 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
402 {
403 return max_t(unsigned long, NILFS_MIN_NRSVSEGS,
404 DIV_ROUND_UP(nsegs * nilfs->ns_r_segments_percentage,
405 100));
406 }
407
408 /**
409 * nilfs_max_segment_count - calculate the maximum number of segments
410 * @nilfs: nilfs object
411 */
412 static u64 nilfs_max_segment_count(struct the_nilfs *nilfs)
413 {
414 u64 max_count = U64_MAX;
415
416 max_count = div64_ul(max_count, nilfs->ns_blocks_per_segment);
417 return min_t(u64, max_count, ULONG_MAX);
418 }
419
420 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs)
421 {
422 nilfs->ns_nsegments = nsegs;
423 nilfs->ns_nrsvsegs = nilfs_nrsvsegs(nilfs, nsegs);
424 }
425
426 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
427 struct nilfs_super_block *sbp)
428 {
429 u64 nsegments, nblocks;
430
431 if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
432 nilfs_err(nilfs->ns_sb,
433 "unsupported revision (superblock rev.=%d.%d, current rev.=%d.%d). Please check the version of mkfs.nilfs(2).",
434 le32_to_cpu(sbp->s_rev_level),
435 le16_to_cpu(sbp->s_minor_rev_level),
436 NILFS_CURRENT_REV, NILFS_MINOR_REV);
437 return -EINVAL;
438 }
439 nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
440 if (nilfs->ns_sbsize > BLOCK_SIZE)
441 return -EINVAL;
442
443 nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
444 if (nilfs->ns_inode_size > nilfs->ns_blocksize) {
445 nilfs_err(nilfs->ns_sb, "too large inode size: %d bytes",
446 nilfs->ns_inode_size);
447 return -EINVAL;
448 } else if (nilfs->ns_inode_size < NILFS_MIN_INODE_SIZE) {
449 nilfs_err(nilfs->ns_sb, "too small inode size: %d bytes",
450 nilfs->ns_inode_size);
451 return -EINVAL;
452 }
453
454 nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
455 if (nilfs->ns_first_ino < NILFS_USER_INO) {
456 nilfs_err(nilfs->ns_sb,
457 "too small lower limit for non-reserved inode numbers: %u",
458 nilfs->ns_first_ino);
459 return -EINVAL;
460 }
461
462 nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
463 if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
464 nilfs_err(nilfs->ns_sb, "too short segment: %lu blocks",
465 nilfs->ns_blocks_per_segment);
466 return -EINVAL;
467 }
468
469 nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
470 nilfs->ns_r_segments_percentage =
471 le32_to_cpu(sbp->s_r_segments_percentage);
472 if (nilfs->ns_r_segments_percentage < 1 ||
473 nilfs->ns_r_segments_percentage > 99) {
474 nilfs_err(nilfs->ns_sb,
475 "invalid reserved segments percentage: %lu",
476 nilfs->ns_r_segments_percentage);
477 return -EINVAL;
478 }
479
480 nsegments = le64_to_cpu(sbp->s_nsegments);
481 if (nsegments > nilfs_max_segment_count(nilfs)) {
482 nilfs_err(nilfs->ns_sb,
483 "segment count %llu exceeds upper limit (%llu segments)",
484 (unsigned long long)nsegments,
485 (unsigned long long)nilfs_max_segment_count(nilfs));
486 return -EINVAL;
487 }
488
489 nblocks = sb_bdev_nr_blocks(nilfs->ns_sb);
490 if (nblocks) {
491 u64 min_block_count = nsegments * nilfs->ns_blocks_per_segment;
492 /*
493 * To avoid failing to mount early device images without a
494 * second superblock, exclude that block count from the
495 * "min_block_count" calculation.
496 */
497
498 if (nblocks < min_block_count) {
499 nilfs_err(nilfs->ns_sb,
500 "total number of segment blocks %llu exceeds device size (%llu blocks)",
501 (unsigned long long)min_block_count,
502 (unsigned long long)nblocks);
503 return -EINVAL;
504 }
505 }
506
507 nilfs_set_nsegments(nilfs, nsegments);
508 nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
509 return 0;
510 }
511
512 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
513 {
514 static unsigned char sum[4];
515 const int sumoff = offsetof(struct nilfs_super_block, s_sum);
516 size_t bytes;
517 u32 crc;
518
519 if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
520 return 0;
521 bytes = le16_to_cpu(sbp->s_bytes);
522 if (bytes < sumoff + 4 || bytes > BLOCK_SIZE)
523 return 0;
524 crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
525 sumoff);
526 crc = crc32_le(crc, sum, 4);
527 crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
528 bytes - sumoff - 4);
529 return crc == le32_to_cpu(sbp->s_sum);
530 }
531
532 /**
533 * nilfs_sb2_bad_offset - check the location of the second superblock
534 * @sbp: superblock raw data buffer
535 * @offset: byte offset of second superblock calculated from device size
536 *
537 * nilfs_sb2_bad_offset() checks if the position on the second
538 * superblock is valid or not based on the filesystem parameters
539 * stored in @sbp. If @offset points to a location within the segment
540 * area, or if the parameters themselves are not normal, it is
541 * determined to be invalid.
542 *
543 * Return Value: true if invalid, false if valid.
544 */
545 static bool nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
546 {
547 unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
548 u32 blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
549 u64 nsegments = le64_to_cpu(sbp->s_nsegments);
550 u64 index;
551
552 if (blocks_per_segment < NILFS_SEG_MIN_BLOCKS ||
553 shift_bits > ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)
554 return true;
555
556 index = offset >> (shift_bits + BLOCK_SIZE_BITS);
557 do_div(index, blocks_per_segment);
558 return index < nsegments;
559 }
560
561 static void nilfs_release_super_block(struct the_nilfs *nilfs)
562 {
563 int i;
564
565 for (i = 0; i < 2; i++) {
566 if (nilfs->ns_sbp[i]) {
567 brelse(nilfs->ns_sbh[i]);
568 nilfs->ns_sbh[i] = NULL;
569 nilfs->ns_sbp[i] = NULL;
570 }
571 }
572 }
573
574 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
575 {
576 brelse(nilfs->ns_sbh[0]);
577 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
578 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
579 nilfs->ns_sbh[1] = NULL;
580 nilfs->ns_sbp[1] = NULL;
581 }
582
583 void nilfs_swap_super_block(struct the_nilfs *nilfs)
584 {
585 struct buffer_head *tsbh = nilfs->ns_sbh[0];
586 struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
587
588 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
589 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
590 nilfs->ns_sbh[1] = tsbh;
591 nilfs->ns_sbp[1] = tsbp;
592 }
593
594 static int nilfs_load_super_block(struct the_nilfs *nilfs,
595 struct super_block *sb, int blocksize,
596 struct nilfs_super_block **sbpp)
597 {
598 struct nilfs_super_block **sbp = nilfs->ns_sbp;
599 struct buffer_head **sbh = nilfs->ns_sbh;
600 u64 sb2off, devsize = bdev_nr_bytes(nilfs->ns_bdev);
601 int valid[2], swp = 0, older;
602
603 if (devsize < NILFS_SEG_MIN_BLOCKS * NILFS_MIN_BLOCK_SIZE + 4096) {
604 nilfs_err(sb, "device size too small");
605 return -EINVAL;
606 }
607 sb2off = NILFS_SB2_OFFSET_BYTES(devsize);
608
609 sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
610 &sbh[0]);
611 sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
612
613 if (!sbp[0]) {
614 if (!sbp[1]) {
615 nilfs_err(sb, "unable to read superblock");
616 return -EIO;
617 }
618 nilfs_warn(sb,
619 "unable to read primary superblock (blocksize = %d)",
620 blocksize);
621 } else if (!sbp[1]) {
622 nilfs_warn(sb,
623 "unable to read secondary superblock (blocksize = %d)",
624 blocksize);
625 }
626
627 /*
628 * Compare two super blocks and set 1 in swp if the secondary
629 * super block is valid and newer. Otherwise, set 0 in swp.
630 */
631 valid[0] = nilfs_valid_sb(sbp[0]);
632 valid[1] = nilfs_valid_sb(sbp[1]);
633 swp = valid[1] && (!valid[0] ||
634 le64_to_cpu(sbp[1]->s_last_cno) >
635 le64_to_cpu(sbp[0]->s_last_cno));
636
637 if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
638 brelse(sbh[1]);
639 sbh[1] = NULL;
640 sbp[1] = NULL;
641 valid[1] = 0;
642 swp = 0;
643 }
644 if (!valid[swp]) {
645 nilfs_release_super_block(nilfs);
646 nilfs_err(sb, "couldn't find nilfs on the device");
647 return -EINVAL;
648 }
649
650 if (!valid[!swp])
651 nilfs_warn(sb,
652 "broken superblock, retrying with spare superblock (blocksize = %d)",
653 blocksize);
654 if (swp)
655 nilfs_swap_super_block(nilfs);
656
657 /*
658 * Calculate the array index of the older superblock data.
659 * If one has been dropped, set index 0 pointing to the remaining one,
660 * otherwise set index 1 pointing to the old one (including if both
661 * are the same).
662 *
663 * Divided case valid[0] valid[1] swp -> older
664 * -------------------------------------------------------------
665 * Both SBs are invalid 0 0 N/A (Error)
666 * SB1 is invalid 0 1 1 0
667 * SB2 is invalid 1 0 0 0
668 * SB2 is newer 1 1 1 0
669 * SB2 is older or the same 1 1 0 1
670 */
671 older = valid[1] ^ swp;
672
673 nilfs->ns_sbwcount = 0;
674 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
675 nilfs->ns_prot_seq = le64_to_cpu(sbp[older]->s_last_seq);
676 *sbpp = sbp[0];
677 return 0;
678 }
679
680 /**
681 * init_nilfs - initialize a NILFS instance.
682 * @nilfs: the_nilfs structure
683 * @sb: super block
684 *
685 * init_nilfs() performs common initialization per block device (e.g.
686 * reading the super block, getting disk layout information, initializing
687 * shared fields in the_nilfs).
688 *
689 * Return Value: On success, 0 is returned. On error, a negative error
690 * code is returned.
691 */
692 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
693 {
694 struct nilfs_super_block *sbp;
695 int blocksize;
696 int err;
697
698 down_write(&nilfs->ns_sem);
699
700 blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
701 if (!blocksize) {
702 nilfs_err(sb, "unable to set blocksize");
703 err = -EINVAL;
704 goto out;
705 }
706 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
707 if (err)
708 goto out;
709
710 err = nilfs_store_magic(sb, sbp);
711 if (err)
712 goto failed_sbh;
713
714 err = nilfs_check_feature_compatibility(sb, sbp);
715 if (err)
716 goto failed_sbh;
717
718 err = nilfs_get_blocksize(sb, sbp, &blocksize);
719 if (err)
720 goto failed_sbh;
721
722 if (blocksize < NILFS_MIN_BLOCK_SIZE) {
723 nilfs_err(sb,
724 "couldn't mount because of unsupported filesystem blocksize %d",
725 blocksize);
726 err = -EINVAL;
727 goto failed_sbh;
728 }
729 if (sb->s_blocksize != blocksize) {
730 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
731
732 if (blocksize < hw_blocksize) {
733 nilfs_err(sb,
734 "blocksize %d too small for device (sector-size = %d)",
735 blocksize, hw_blocksize);
736 err = -EINVAL;
737 goto failed_sbh;
738 }
739 nilfs_release_super_block(nilfs);
740 if (!sb_set_blocksize(sb, blocksize)) {
741 nilfs_err(sb, "bad blocksize %d", blocksize);
742 err = -EINVAL;
743 goto out;
744 }
745
746 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
747 if (err)
748 goto out;
749 /*
750 * Not to failed_sbh; sbh is released automatically
751 * when reloading fails.
752 */
753 }
754 nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
755 nilfs->ns_blocksize = blocksize;
756
757 get_random_bytes(&nilfs->ns_next_generation,
758 sizeof(nilfs->ns_next_generation));
759
760 err = nilfs_store_disk_layout(nilfs, sbp);
761 if (err)
762 goto failed_sbh;
763
764 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
765
766 nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
767
768 err = nilfs_store_log_cursor(nilfs, sbp);
769 if (err)
770 goto failed_sbh;
771
772 set_nilfs_init(nilfs);
773 err = 0;
774 out:
775 up_write(&nilfs->ns_sem);
776 return err;
777
778 failed_sbh:
779 nilfs_release_super_block(nilfs);
780 goto out;
781 }
782
783 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
784 size_t nsegs)
785 {
786 sector_t seg_start, seg_end;
787 sector_t start = 0, nblocks = 0;
788 unsigned int sects_per_block;
789 __u64 *sn;
790 int ret = 0;
791
792 sects_per_block = (1 << nilfs->ns_blocksize_bits) /
793 bdev_logical_block_size(nilfs->ns_bdev);
794 for (sn = segnump; sn < segnump + nsegs; sn++) {
795 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
796
797 if (!nblocks) {
798 start = seg_start;
799 nblocks = seg_end - seg_start + 1;
800 } else if (start + nblocks == seg_start) {
801 nblocks += seg_end - seg_start + 1;
802 } else {
803 ret = blkdev_issue_discard(nilfs->ns_bdev,
804 start * sects_per_block,
805 nblocks * sects_per_block,
806 GFP_NOFS);
807 if (ret < 0)
808 return ret;
809 nblocks = 0;
810 }
811 }
812 if (nblocks)
813 ret = blkdev_issue_discard(nilfs->ns_bdev,
814 start * sects_per_block,
815 nblocks * sects_per_block,
816 GFP_NOFS);
817 return ret;
818 }
819
820 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
821 {
822 unsigned long ncleansegs;
823
824 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
825 *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
826 return 0;
827 }
828
829 int nilfs_near_disk_full(struct the_nilfs *nilfs)
830 {
831 unsigned long ncleansegs, nincsegs;
832
833 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
834 nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
835 nilfs->ns_blocks_per_segment + 1;
836
837 return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
838 }
839
840 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
841 {
842 struct rb_node *n;
843 struct nilfs_root *root;
844
845 spin_lock(&nilfs->ns_cptree_lock);
846 n = nilfs->ns_cptree.rb_node;
847 while (n) {
848 root = rb_entry(n, struct nilfs_root, rb_node);
849
850 if (cno < root->cno) {
851 n = n->rb_left;
852 } else if (cno > root->cno) {
853 n = n->rb_right;
854 } else {
855 refcount_inc(&root->count);
856 spin_unlock(&nilfs->ns_cptree_lock);
857 return root;
858 }
859 }
860 spin_unlock(&nilfs->ns_cptree_lock);
861
862 return NULL;
863 }
864
865 struct nilfs_root *
866 nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
867 {
868 struct rb_node **p, *parent;
869 struct nilfs_root *root, *new;
870 int err;
871
872 root = nilfs_lookup_root(nilfs, cno);
873 if (root)
874 return root;
875
876 new = kzalloc(sizeof(*root), GFP_KERNEL);
877 if (!new)
878 return NULL;
879
880 spin_lock(&nilfs->ns_cptree_lock);
881
882 p = &nilfs->ns_cptree.rb_node;
883 parent = NULL;
884
885 while (*p) {
886 parent = *p;
887 root = rb_entry(parent, struct nilfs_root, rb_node);
888
889 if (cno < root->cno) {
890 p = &(*p)->rb_left;
891 } else if (cno > root->cno) {
892 p = &(*p)->rb_right;
893 } else {
894 refcount_inc(&root->count);
895 spin_unlock(&nilfs->ns_cptree_lock);
896 kfree(new);
897 return root;
898 }
899 }
900
901 new->cno = cno;
902 new->ifile = NULL;
903 new->nilfs = nilfs;
904 refcount_set(&new->count, 1);
905 atomic64_set(&new->inodes_count, 0);
906 atomic64_set(&new->blocks_count, 0);
907
908 rb_link_node(&new->rb_node, parent, p);
909 rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
910
911 spin_unlock(&nilfs->ns_cptree_lock);
912
913 err = nilfs_sysfs_create_snapshot_group(new);
914 if (err) {
915 kfree(new);
916 new = NULL;
917 }
918
919 return new;
920 }
921
922 void nilfs_put_root(struct nilfs_root *root)
923 {
924 struct the_nilfs *nilfs = root->nilfs;
925
926 if (refcount_dec_and_lock(&root->count, &nilfs->ns_cptree_lock)) {
927 rb_erase(&root->rb_node, &nilfs->ns_cptree);
928 spin_unlock(&nilfs->ns_cptree_lock);
929
930 nilfs_sysfs_delete_snapshot_group(root);
931 iput(root->ifile);
932
933 kfree(root);
934 }
935 }
936
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