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/log2.h>
16 #include <linux/crc32.h>
17 #include "nilfs.h"
18 #include "segment.h"
19 #include "alloc.h"
20 #include "cpfile.h"
21 #include "sufile.h"
22 #include "dat.h"
23 #include "segbuf.h"
24
25
26 static int nilfs_valid_sb(struct nilfs_super_block *sbp);
27
nilfs_set_last_segment(struct the_nilfs * nilfs,sector_t start_blocknr,u64 seq,__u64 cno)28 void nilfs_set_last_segment(struct the_nilfs *nilfs,
29 sector_t start_blocknr, u64 seq, __u64 cno)
30 {
31 spin_lock(&nilfs->ns_last_segment_lock);
32 nilfs->ns_last_pseg = start_blocknr;
33 nilfs->ns_last_seq = seq;
34 nilfs->ns_last_cno = cno;
35
36 if (!nilfs_sb_dirty(nilfs)) {
37 if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
38 goto stay_cursor;
39
40 set_nilfs_sb_dirty(nilfs);
41 }
42 nilfs->ns_prev_seq = nilfs->ns_last_seq;
43
44 stay_cursor:
45 spin_unlock(&nilfs->ns_last_segment_lock);
46 }
47
48 /**
49 * alloc_nilfs - allocate a nilfs object
50 * @sb: super block instance
51 *
52 * Return: a pointer to the allocated nilfs object on success, or NULL on
53 * failure.
54 */
alloc_nilfs(struct super_block * sb)55 struct the_nilfs *alloc_nilfs(struct super_block *sb)
56 {
57 struct the_nilfs *nilfs;
58
59 nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
60 if (!nilfs)
61 return NULL;
62
63 nilfs->ns_sb = sb;
64 nilfs->ns_bdev = sb->s_bdev;
65 atomic_set(&nilfs->ns_ndirtyblks, 0);
66 init_rwsem(&nilfs->ns_sem);
67 mutex_init(&nilfs->ns_snapshot_mount_mutex);
68 INIT_LIST_HEAD(&nilfs->ns_dirty_files);
69 INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
70 spin_lock_init(&nilfs->ns_inode_lock);
71 spin_lock_init(&nilfs->ns_last_segment_lock);
72 nilfs->ns_cptree = RB_ROOT;
73 spin_lock_init(&nilfs->ns_cptree_lock);
74 init_rwsem(&nilfs->ns_segctor_sem);
75 nilfs->ns_sb_update_freq = NILFS_SB_FREQ;
76
77 return nilfs;
78 }
79
80 /**
81 * destroy_nilfs - destroy nilfs object
82 * @nilfs: nilfs object to be released
83 */
destroy_nilfs(struct the_nilfs * nilfs)84 void destroy_nilfs(struct the_nilfs *nilfs)
85 {
86 might_sleep();
87 if (nilfs_init(nilfs)) {
88 brelse(nilfs->ns_sbh[0]);
89 brelse(nilfs->ns_sbh[1]);
90 }
91 kfree(nilfs);
92 }
93
nilfs_load_super_root(struct the_nilfs * nilfs,struct super_block * sb,sector_t sr_block)94 static int nilfs_load_super_root(struct the_nilfs *nilfs,
95 struct super_block *sb, sector_t sr_block)
96 {
97 struct buffer_head *bh_sr;
98 struct nilfs_super_root *raw_sr;
99 struct nilfs_super_block **sbp = nilfs->ns_sbp;
100 struct nilfs_inode *rawi;
101 unsigned int dat_entry_size, segment_usage_size, checkpoint_size;
102 unsigned int inode_size;
103 int err;
104
105 err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
106 if (unlikely(err))
107 return err;
108
109 down_read(&nilfs->ns_sem);
110 dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
111 checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
112 segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
113 up_read(&nilfs->ns_sem);
114
115 inode_size = nilfs->ns_inode_size;
116
117 rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
118 err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
119 if (err)
120 goto failed;
121
122 rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
123 err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
124 if (err)
125 goto failed_dat;
126
127 rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
128 err = nilfs_sufile_read(sb, segment_usage_size, rawi,
129 &nilfs->ns_sufile);
130 if (err)
131 goto failed_cpfile;
132
133 raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
134 nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
135
136 failed:
137 brelse(bh_sr);
138 return err;
139
140 failed_cpfile:
141 iput(nilfs->ns_cpfile);
142
143 failed_dat:
144 iput(nilfs->ns_dat);
145 goto failed;
146 }
147
nilfs_init_recovery_info(struct nilfs_recovery_info * ri)148 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
149 {
150 memset(ri, 0, sizeof(*ri));
151 INIT_LIST_HEAD(&ri->ri_used_segments);
152 }
153
nilfs_clear_recovery_info(struct nilfs_recovery_info * ri)154 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
155 {
156 nilfs_dispose_segment_list(&ri->ri_used_segments);
157 }
158
159 /**
160 * nilfs_store_log_cursor - load log cursor from a super block
161 * @nilfs: nilfs object
162 * @sbp: buffer storing super block to be read
163 *
164 * nilfs_store_log_cursor() reads the last position of the log
165 * containing a super root from a given super block, and initializes
166 * relevant information on the nilfs object preparatory for log
167 * scanning and recovery.
168 *
169 * Return: 0 on success, or %-EINVAL if current segment number is out
170 * of range.
171 */
nilfs_store_log_cursor(struct the_nilfs * nilfs,struct nilfs_super_block * sbp)172 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
173 struct nilfs_super_block *sbp)
174 {
175 int ret = 0;
176
177 nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
178 nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
179 nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
180
181 nilfs->ns_prev_seq = nilfs->ns_last_seq;
182 nilfs->ns_seg_seq = nilfs->ns_last_seq;
183 nilfs->ns_segnum =
184 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
185 nilfs->ns_cno = nilfs->ns_last_cno + 1;
186 if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
187 nilfs_err(nilfs->ns_sb,
188 "pointed segment number is out of range: segnum=%llu, nsegments=%lu",
189 (unsigned long long)nilfs->ns_segnum,
190 nilfs->ns_nsegments);
191 ret = -EINVAL;
192 }
193 return ret;
194 }
195
196 /**
197 * nilfs_get_blocksize - get block size from raw superblock data
198 * @sb: super block instance
199 * @sbp: superblock raw data buffer
200 * @blocksize: place to store block size
201 *
202 * nilfs_get_blocksize() calculates the block size from the block size
203 * exponent information written in @sbp and stores it in @blocksize,
204 * or aborts with an error message if it's too large.
205 *
206 * Return: 0 on success, or %-EINVAL if the block size is too large.
207 */
nilfs_get_blocksize(struct super_block * sb,struct nilfs_super_block * sbp,int * blocksize)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 * Return: 0 on success, or one of the following negative error codes on
233 * failure:
234 * * %-EINVAL - No valid segment found.
235 * * %-EIO - I/O error.
236 * * %-ENOMEM - Insufficient memory available.
237 * * %-EROFS - Read only device or RO compat mode (if recovery is required)
238 */
load_nilfs(struct the_nilfs * nilfs,struct super_block * sb)239 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
240 {
241 struct nilfs_recovery_info ri;
242 unsigned int s_flags = sb->s_flags;
243 int really_read_only = bdev_read_only(nilfs->ns_bdev);
244 int valid_fs = nilfs_valid_fs(nilfs);
245 int err;
246
247 if (!valid_fs) {
248 nilfs_warn(sb, "mounting unchecked fs");
249 if (s_flags & SB_RDONLY) {
250 nilfs_info(sb,
251 "recovery required for readonly filesystem");
252 nilfs_info(sb,
253 "write access will be enabled during recovery");
254 }
255 }
256
257 nilfs_init_recovery_info(&ri);
258
259 err = nilfs_search_super_root(nilfs, &ri);
260 if (unlikely(err)) {
261 struct nilfs_super_block **sbp = nilfs->ns_sbp;
262 int blocksize;
263
264 if (err != -EINVAL)
265 goto scan_error;
266
267 if (!nilfs_valid_sb(sbp[1])) {
268 nilfs_warn(sb,
269 "unable to fall back to spare super block");
270 goto scan_error;
271 }
272 nilfs_info(sb, "trying rollback from an earlier position");
273
274 /*
275 * restore super block with its spare and reconfigure
276 * relevant states of the nilfs object.
277 */
278 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
279 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
280 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
281
282 /* verify consistency between two super blocks */
283 err = nilfs_get_blocksize(sb, sbp[0], &blocksize);
284 if (err)
285 goto scan_error;
286
287 if (blocksize != nilfs->ns_blocksize) {
288 nilfs_warn(sb,
289 "blocksize differs between two super blocks (%d != %d)",
290 blocksize, nilfs->ns_blocksize);
291 err = -EINVAL;
292 goto scan_error;
293 }
294
295 err = nilfs_store_log_cursor(nilfs, sbp[0]);
296 if (err)
297 goto scan_error;
298
299 /* drop clean flag to allow roll-forward and recovery */
300 nilfs->ns_mount_state &= ~NILFS_VALID_FS;
301 valid_fs = 0;
302
303 err = nilfs_search_super_root(nilfs, &ri);
304 if (err)
305 goto scan_error;
306 }
307
308 err = nilfs_load_super_root(nilfs, sb, ri.ri_super_root);
309 if (unlikely(err)) {
310 nilfs_err(sb, "error %d while loading super root", err);
311 goto failed;
312 }
313
314 err = nilfs_sysfs_create_device_group(sb);
315 if (unlikely(err))
316 goto sysfs_error;
317
318 if (valid_fs)
319 goto skip_recovery;
320
321 if (s_flags & SB_RDONLY) {
322 __u64 features;
323
324 if (nilfs_test_opt(nilfs, NORECOVERY)) {
325 nilfs_info(sb,
326 "norecovery option specified, skipping roll-forward recovery");
327 goto skip_recovery;
328 }
329 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
330 ~NILFS_FEATURE_COMPAT_RO_SUPP;
331 if (features) {
332 nilfs_err(sb,
333 "couldn't proceed with recovery because of unsupported optional features (%llx)",
334 (unsigned long long)features);
335 err = -EROFS;
336 goto failed_unload;
337 }
338 if (really_read_only) {
339 nilfs_err(sb,
340 "write access unavailable, cannot proceed");
341 err = -EROFS;
342 goto failed_unload;
343 }
344 sb->s_flags &= ~SB_RDONLY;
345 } else if (nilfs_test_opt(nilfs, NORECOVERY)) {
346 nilfs_err(sb,
347 "recovery cancelled because norecovery option was specified for a read/write mount");
348 err = -EINVAL;
349 goto failed_unload;
350 }
351
352 err = nilfs_salvage_orphan_logs(nilfs, sb, &ri);
353 if (err)
354 goto failed_unload;
355
356 down_write(&nilfs->ns_sem);
357 nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
358 err = nilfs_cleanup_super(sb);
359 up_write(&nilfs->ns_sem);
360
361 if (err) {
362 nilfs_err(sb,
363 "error %d updating super block. recovery unfinished.",
364 err);
365 goto failed_unload;
366 }
367 nilfs_info(sb, "recovery complete");
368
369 skip_recovery:
370 nilfs_clear_recovery_info(&ri);
371 sb->s_flags = s_flags;
372 return 0;
373
374 scan_error:
375 nilfs_err(sb, "error %d while searching super root", err);
376 goto failed;
377
378 failed_unload:
379 nilfs_sysfs_delete_device_group(nilfs);
380
381 sysfs_error:
382 iput(nilfs->ns_cpfile);
383 iput(nilfs->ns_sufile);
384 iput(nilfs->ns_dat);
385
386 failed:
387 nilfs_clear_recovery_info(&ri);
388 sb->s_flags = s_flags;
389 return err;
390 }
391
nilfs_max_size(unsigned int blkbits)392 static unsigned long long nilfs_max_size(unsigned int blkbits)
393 {
394 unsigned int max_bits;
395 unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
396
397 max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
398 if (max_bits < 64)
399 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
400 return res;
401 }
402
403 /**
404 * nilfs_nrsvsegs - calculate the number of reserved segments
405 * @nilfs: nilfs object
406 * @nsegs: total number of segments
407 *
408 * Return: Number of reserved segments.
409 */
nilfs_nrsvsegs(struct the_nilfs * nilfs,unsigned long nsegs)410 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
411 {
412 return max_t(unsigned long, NILFS_MIN_NRSVSEGS,
413 DIV_ROUND_UP(nsegs * nilfs->ns_r_segments_percentage,
414 100));
415 }
416
417 /**
418 * nilfs_max_segment_count - calculate the maximum number of segments
419 * @nilfs: nilfs object
420 *
421 * Return: Maximum number of segments
422 */
nilfs_max_segment_count(struct the_nilfs * nilfs)423 static u64 nilfs_max_segment_count(struct the_nilfs *nilfs)
424 {
425 u64 max_count = U64_MAX;
426
427 max_count = div64_ul(max_count, nilfs->ns_blocks_per_segment);
428 return min_t(u64, max_count, ULONG_MAX);
429 }
430
nilfs_set_nsegments(struct the_nilfs * nilfs,unsigned long nsegs)431 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs)
432 {
433 nilfs->ns_nsegments = nsegs;
434 nilfs->ns_nrsvsegs = nilfs_nrsvsegs(nilfs, nsegs);
435 }
436
nilfs_store_disk_layout(struct the_nilfs * nilfs,struct nilfs_super_block * sbp)437 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
438 struct nilfs_super_block *sbp)
439 {
440 u64 nsegments, nblocks;
441
442 if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
443 nilfs_err(nilfs->ns_sb,
444 "unsupported revision (superblock rev.=%d.%d, current rev.=%d.%d). Please check the version of mkfs.nilfs(2).",
445 le32_to_cpu(sbp->s_rev_level),
446 le16_to_cpu(sbp->s_minor_rev_level),
447 NILFS_CURRENT_REV, NILFS_MINOR_REV);
448 return -EINVAL;
449 }
450 nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
451 if (nilfs->ns_sbsize > BLOCK_SIZE)
452 return -EINVAL;
453
454 nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
455 if (nilfs->ns_inode_size > nilfs->ns_blocksize) {
456 nilfs_err(nilfs->ns_sb, "too large inode size: %d bytes",
457 nilfs->ns_inode_size);
458 return -EINVAL;
459 } else if (nilfs->ns_inode_size < NILFS_MIN_INODE_SIZE) {
460 nilfs_err(nilfs->ns_sb, "too small inode size: %d bytes",
461 nilfs->ns_inode_size);
462 return -EINVAL;
463 }
464
465 nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
466 if (nilfs->ns_first_ino < NILFS_USER_INO) {
467 nilfs_err(nilfs->ns_sb,
468 "too small lower limit for non-reserved inode numbers: %u",
469 nilfs->ns_first_ino);
470 return -EINVAL;
471 }
472
473 nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
474 if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
475 nilfs_err(nilfs->ns_sb, "too short segment: %lu blocks",
476 nilfs->ns_blocks_per_segment);
477 return -EINVAL;
478 }
479
480 nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
481 nilfs->ns_r_segments_percentage =
482 le32_to_cpu(sbp->s_r_segments_percentage);
483 if (nilfs->ns_r_segments_percentage < 1 ||
484 nilfs->ns_r_segments_percentage > 99) {
485 nilfs_err(nilfs->ns_sb,
486 "invalid reserved segments percentage: %lu",
487 nilfs->ns_r_segments_percentage);
488 return -EINVAL;
489 }
490
491 nsegments = le64_to_cpu(sbp->s_nsegments);
492 if (nsegments > nilfs_max_segment_count(nilfs)) {
493 nilfs_err(nilfs->ns_sb,
494 "segment count %llu exceeds upper limit (%llu segments)",
495 (unsigned long long)nsegments,
496 (unsigned long long)nilfs_max_segment_count(nilfs));
497 return -EINVAL;
498 }
499
500 nblocks = sb_bdev_nr_blocks(nilfs->ns_sb);
501 if (nblocks) {
502 u64 min_block_count = nsegments * nilfs->ns_blocks_per_segment;
503 /*
504 * To avoid failing to mount early device images without a
505 * second superblock, exclude that block count from the
506 * "min_block_count" calculation.
507 */
508
509 if (nblocks < min_block_count) {
510 nilfs_err(nilfs->ns_sb,
511 "total number of segment blocks %llu exceeds device size (%llu blocks)",
512 (unsigned long long)min_block_count,
513 (unsigned long long)nblocks);
514 return -EINVAL;
515 }
516 }
517
518 nilfs_set_nsegments(nilfs, nsegments);
519 nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
520 return 0;
521 }
522
nilfs_valid_sb(struct nilfs_super_block * sbp)523 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
524 {
525 static unsigned char sum[4];
526 const int sumoff = offsetof(struct nilfs_super_block, s_sum);
527 size_t bytes;
528 u32 crc;
529
530 if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
531 return 0;
532 bytes = le16_to_cpu(sbp->s_bytes);
533 if (bytes < sumoff + 4 || bytes > BLOCK_SIZE)
534 return 0;
535 crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
536 sumoff);
537 crc = crc32_le(crc, sum, 4);
538 crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
539 bytes - sumoff - 4);
540 return crc == le32_to_cpu(sbp->s_sum);
541 }
542
543 /**
544 * nilfs_sb2_bad_offset - check the location of the second superblock
545 * @sbp: superblock raw data buffer
546 * @offset: byte offset of second superblock calculated from device size
547 *
548 * nilfs_sb2_bad_offset() checks if the position on the second
549 * superblock is valid or not based on the filesystem parameters
550 * stored in @sbp. If @offset points to a location within the segment
551 * area, or if the parameters themselves are not normal, it is
552 * determined to be invalid.
553 *
554 * Return: true if invalid, false if valid.
555 */
nilfs_sb2_bad_offset(struct nilfs_super_block * sbp,u64 offset)556 static bool nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
557 {
558 unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
559 u32 blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
560 u64 nsegments = le64_to_cpu(sbp->s_nsegments);
561 u64 index;
562
563 if (blocks_per_segment < NILFS_SEG_MIN_BLOCKS ||
564 shift_bits > ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)
565 return true;
566
567 index = offset >> (shift_bits + BLOCK_SIZE_BITS);
568 do_div(index, blocks_per_segment);
569 return index < nsegments;
570 }
571
nilfs_release_super_block(struct the_nilfs * nilfs)572 static void nilfs_release_super_block(struct the_nilfs *nilfs)
573 {
574 int i;
575
576 for (i = 0; i < 2; i++) {
577 if (nilfs->ns_sbp[i]) {
578 brelse(nilfs->ns_sbh[i]);
579 nilfs->ns_sbh[i] = NULL;
580 nilfs->ns_sbp[i] = NULL;
581 }
582 }
583 }
584
nilfs_fall_back_super_block(struct the_nilfs * nilfs)585 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
586 {
587 brelse(nilfs->ns_sbh[0]);
588 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
589 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
590 nilfs->ns_sbh[1] = NULL;
591 nilfs->ns_sbp[1] = NULL;
592 }
593
nilfs_swap_super_block(struct the_nilfs * nilfs)594 void nilfs_swap_super_block(struct the_nilfs *nilfs)
595 {
596 struct buffer_head *tsbh = nilfs->ns_sbh[0];
597 struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
598
599 nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
600 nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
601 nilfs->ns_sbh[1] = tsbh;
602 nilfs->ns_sbp[1] = tsbp;
603 }
604
nilfs_load_super_block(struct the_nilfs * nilfs,struct super_block * sb,int blocksize,struct nilfs_super_block ** sbpp)605 static int nilfs_load_super_block(struct the_nilfs *nilfs,
606 struct super_block *sb, int blocksize,
607 struct nilfs_super_block **sbpp)
608 {
609 struct nilfs_super_block **sbp = nilfs->ns_sbp;
610 struct buffer_head **sbh = nilfs->ns_sbh;
611 u64 sb2off, devsize = bdev_nr_bytes(nilfs->ns_bdev);
612 int valid[2], swp = 0, older;
613
614 if (devsize < NILFS_SEG_MIN_BLOCKS * NILFS_MIN_BLOCK_SIZE + 4096) {
615 nilfs_err(sb, "device size too small");
616 return -EINVAL;
617 }
618 sb2off = NILFS_SB2_OFFSET_BYTES(devsize);
619
620 sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
621 &sbh[0]);
622 sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
623
624 if (!sbp[0]) {
625 if (!sbp[1]) {
626 nilfs_err(sb, "unable to read superblock");
627 return -EIO;
628 }
629 nilfs_warn(sb,
630 "unable to read primary superblock (blocksize = %d)",
631 blocksize);
632 } else if (!sbp[1]) {
633 nilfs_warn(sb,
634 "unable to read secondary superblock (blocksize = %d)",
635 blocksize);
636 }
637
638 /*
639 * Compare two super blocks and set 1 in swp if the secondary
640 * super block is valid and newer. Otherwise, set 0 in swp.
641 */
642 valid[0] = nilfs_valid_sb(sbp[0]);
643 valid[1] = nilfs_valid_sb(sbp[1]);
644 swp = valid[1] && (!valid[0] ||
645 le64_to_cpu(sbp[1]->s_last_cno) >
646 le64_to_cpu(sbp[0]->s_last_cno));
647
648 if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
649 brelse(sbh[1]);
650 sbh[1] = NULL;
651 sbp[1] = NULL;
652 valid[1] = 0;
653 swp = 0;
654 }
655 if (!valid[swp]) {
656 nilfs_release_super_block(nilfs);
657 nilfs_err(sb, "couldn't find nilfs on the device");
658 return -EINVAL;
659 }
660
661 if (!valid[!swp])
662 nilfs_warn(sb,
663 "broken superblock, retrying with spare superblock (blocksize = %d)",
664 blocksize);
665 if (swp)
666 nilfs_swap_super_block(nilfs);
667
668 /*
669 * Calculate the array index of the older superblock data.
670 * If one has been dropped, set index 0 pointing to the remaining one,
671 * otherwise set index 1 pointing to the old one (including if both
672 * are the same).
673 *
674 * Divided case valid[0] valid[1] swp -> older
675 * -------------------------------------------------------------
676 * Both SBs are invalid 0 0 N/A (Error)
677 * SB1 is invalid 0 1 1 0
678 * SB2 is invalid 1 0 0 0
679 * SB2 is newer 1 1 1 0
680 * SB2 is older or the same 1 1 0 1
681 */
682 older = valid[1] ^ swp;
683
684 nilfs->ns_sbwcount = 0;
685 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
686 nilfs->ns_prot_seq = le64_to_cpu(sbp[older]->s_last_seq);
687 *sbpp = sbp[0];
688 return 0;
689 }
690
691 /**
692 * init_nilfs - initialize a NILFS instance.
693 * @nilfs: the_nilfs structure
694 * @sb: super block
695 *
696 * init_nilfs() performs common initialization per block device (e.g.
697 * reading the super block, getting disk layout information, initializing
698 * shared fields in the_nilfs).
699 *
700 * Return: 0 on success, or a negative error code on failure.
701 */
init_nilfs(struct the_nilfs * nilfs,struct super_block * sb)702 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
703 {
704 struct nilfs_super_block *sbp;
705 int blocksize;
706 int err;
707
708 blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
709 if (!blocksize) {
710 nilfs_err(sb, "unable to set blocksize");
711 err = -EINVAL;
712 goto out;
713 }
714 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
715 if (err)
716 goto out;
717
718 err = nilfs_store_magic(sb, sbp);
719 if (err)
720 goto failed_sbh;
721
722 err = nilfs_check_feature_compatibility(sb, sbp);
723 if (err)
724 goto failed_sbh;
725
726 err = nilfs_get_blocksize(sb, sbp, &blocksize);
727 if (err)
728 goto failed_sbh;
729
730 if (blocksize < NILFS_MIN_BLOCK_SIZE) {
731 nilfs_err(sb,
732 "couldn't mount because of unsupported filesystem blocksize %d",
733 blocksize);
734 err = -EINVAL;
735 goto failed_sbh;
736 }
737 if (sb->s_blocksize != blocksize) {
738 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
739
740 if (blocksize < hw_blocksize) {
741 nilfs_err(sb,
742 "blocksize %d too small for device (sector-size = %d)",
743 blocksize, hw_blocksize);
744 err = -EINVAL;
745 goto failed_sbh;
746 }
747 nilfs_release_super_block(nilfs);
748 if (!sb_set_blocksize(sb, blocksize)) {
749 nilfs_err(sb, "bad blocksize %d", blocksize);
750 err = -EINVAL;
751 goto out;
752 }
753
754 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
755 if (err)
756 goto out;
757 /*
758 * Not to failed_sbh; sbh is released automatically
759 * when reloading fails.
760 */
761 }
762 nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
763 nilfs->ns_blocksize = blocksize;
764
765 err = nilfs_store_disk_layout(nilfs, sbp);
766 if (err)
767 goto failed_sbh;
768
769 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
770
771 nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
772
773 err = nilfs_store_log_cursor(nilfs, sbp);
774 if (err)
775 goto failed_sbh;
776
777 set_nilfs_init(nilfs);
778 err = 0;
779 out:
780 return err;
781
782 failed_sbh:
783 nilfs_release_super_block(nilfs);
784 goto out;
785 }
786
nilfs_discard_segments(struct the_nilfs * nilfs,__u64 * segnump,size_t nsegs)787 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
788 size_t nsegs)
789 {
790 sector_t seg_start, seg_end;
791 sector_t start = 0, nblocks = 0;
792 unsigned int sects_per_block;
793 __u64 *sn;
794 int ret = 0;
795
796 sects_per_block = (1 << nilfs->ns_blocksize_bits) /
797 bdev_logical_block_size(nilfs->ns_bdev);
798 for (sn = segnump; sn < segnump + nsegs; sn++) {
799 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
800
801 if (!nblocks) {
802 start = seg_start;
803 nblocks = seg_end - seg_start + 1;
804 } else if (start + nblocks == seg_start) {
805 nblocks += seg_end - seg_start + 1;
806 } else {
807 ret = blkdev_issue_discard(nilfs->ns_bdev,
808 start * sects_per_block,
809 nblocks * sects_per_block,
810 GFP_NOFS);
811 if (ret < 0)
812 return ret;
813 nblocks = 0;
814 }
815 }
816 if (nblocks)
817 ret = blkdev_issue_discard(nilfs->ns_bdev,
818 start * sects_per_block,
819 nblocks * sects_per_block,
820 GFP_NOFS);
821 return ret;
822 }
823
nilfs_count_free_blocks(struct the_nilfs * nilfs,sector_t * nblocks)824 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
825 {
826 unsigned long ncleansegs;
827
828 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
829 *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
830 return 0;
831 }
832
nilfs_near_disk_full(struct the_nilfs * nilfs)833 int nilfs_near_disk_full(struct the_nilfs *nilfs)
834 {
835 unsigned long ncleansegs, nincsegs;
836
837 ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
838 nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
839 nilfs->ns_blocks_per_segment + 1;
840
841 return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
842 }
843
nilfs_lookup_root(struct the_nilfs * nilfs,__u64 cno)844 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
845 {
846 struct rb_node *n;
847 struct nilfs_root *root;
848
849 spin_lock(&nilfs->ns_cptree_lock);
850 n = nilfs->ns_cptree.rb_node;
851 while (n) {
852 root = rb_entry(n, struct nilfs_root, rb_node);
853
854 if (cno < root->cno) {
855 n = n->rb_left;
856 } else if (cno > root->cno) {
857 n = n->rb_right;
858 } else {
859 refcount_inc(&root->count);
860 spin_unlock(&nilfs->ns_cptree_lock);
861 return root;
862 }
863 }
864 spin_unlock(&nilfs->ns_cptree_lock);
865
866 return NULL;
867 }
868
869 struct nilfs_root *
nilfs_find_or_create_root(struct the_nilfs * nilfs,__u64 cno)870 nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
871 {
872 struct rb_node **p, *parent;
873 struct nilfs_root *root, *new;
874 int err;
875
876 root = nilfs_lookup_root(nilfs, cno);
877 if (root)
878 return root;
879
880 new = kzalloc(sizeof(*root), GFP_KERNEL);
881 if (!new)
882 return NULL;
883
884 spin_lock(&nilfs->ns_cptree_lock);
885
886 p = &nilfs->ns_cptree.rb_node;
887 parent = NULL;
888
889 while (*p) {
890 parent = *p;
891 root = rb_entry(parent, struct nilfs_root, rb_node);
892
893 if (cno < root->cno) {
894 p = &(*p)->rb_left;
895 } else if (cno > root->cno) {
896 p = &(*p)->rb_right;
897 } else {
898 refcount_inc(&root->count);
899 spin_unlock(&nilfs->ns_cptree_lock);
900 kfree(new);
901 return root;
902 }
903 }
904
905 new->cno = cno;
906 new->ifile = NULL;
907 new->nilfs = nilfs;
908 refcount_set(&new->count, 1);
909 atomic64_set(&new->inodes_count, 0);
910 atomic64_set(&new->blocks_count, 0);
911
912 rb_link_node(&new->rb_node, parent, p);
913 rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
914
915 spin_unlock(&nilfs->ns_cptree_lock);
916
917 err = nilfs_sysfs_create_snapshot_group(new);
918 if (err) {
919 kfree(new);
920 new = NULL;
921 }
922
923 return new;
924 }
925
nilfs_put_root(struct nilfs_root * root)926 void nilfs_put_root(struct nilfs_root *root)
927 {
928 struct the_nilfs *nilfs = root->nilfs;
929
930 if (refcount_dec_and_lock(&root->count, &nilfs->ns_cptree_lock)) {
931 rb_erase(&root->rb_node, &nilfs->ns_cptree);
932 spin_unlock(&nilfs->ns_cptree_lock);
933
934 nilfs_sysfs_delete_snapshot_group(root);
935 iput(root->ifile);
936
937 kfree(root);
938 }
939 }
940