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1 /*
2  * the_nilfs.c - the_nilfs shared structure.
3  *
4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * Written by Ryusuke Konishi.
17  *
18  */
19 
20 #include <linux/buffer_head.h>
21 #include <linux/slab.h>
22 #include <linux/blkdev.h>
23 #include <linux/backing-dev.h>
24 #include <linux/random.h>
25 #include <linux/crc32.h>
26 #include "nilfs.h"
27 #include "segment.h"
28 #include "alloc.h"
29 #include "cpfile.h"
30 #include "sufile.h"
31 #include "dat.h"
32 #include "segbuf.h"
33 
34 
35 static int nilfs_valid_sb(struct nilfs_super_block *sbp);
36 
nilfs_set_last_segment(struct the_nilfs * nilfs,sector_t start_blocknr,u64 seq,__u64 cno)37 void nilfs_set_last_segment(struct the_nilfs *nilfs,
38 			    sector_t start_blocknr, u64 seq, __u64 cno)
39 {
40 	spin_lock(&nilfs->ns_last_segment_lock);
41 	nilfs->ns_last_pseg = start_blocknr;
42 	nilfs->ns_last_seq = seq;
43 	nilfs->ns_last_cno = cno;
44 
45 	if (!nilfs_sb_dirty(nilfs)) {
46 		if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
47 			goto stay_cursor;
48 
49 		set_nilfs_sb_dirty(nilfs);
50 	}
51 	nilfs->ns_prev_seq = nilfs->ns_last_seq;
52 
53  stay_cursor:
54 	spin_unlock(&nilfs->ns_last_segment_lock);
55 }
56 
57 /**
58  * alloc_nilfs - allocate a nilfs object
59  * @sb: super block instance
60  *
61  * Return Value: On success, pointer to the_nilfs is returned.
62  * On error, NULL is returned.
63  */
alloc_nilfs(struct super_block * sb)64 struct the_nilfs *alloc_nilfs(struct super_block *sb)
65 {
66 	struct the_nilfs *nilfs;
67 
68 	nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
69 	if (!nilfs)
70 		return NULL;
71 
72 	nilfs->ns_sb = sb;
73 	nilfs->ns_bdev = sb->s_bdev;
74 	atomic_set(&nilfs->ns_ndirtyblks, 0);
75 	init_rwsem(&nilfs->ns_sem);
76 	mutex_init(&nilfs->ns_snapshot_mount_mutex);
77 	INIT_LIST_HEAD(&nilfs->ns_dirty_files);
78 	INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
79 	spin_lock_init(&nilfs->ns_inode_lock);
80 	spin_lock_init(&nilfs->ns_next_gen_lock);
81 	spin_lock_init(&nilfs->ns_last_segment_lock);
82 	nilfs->ns_cptree = RB_ROOT;
83 	spin_lock_init(&nilfs->ns_cptree_lock);
84 	init_rwsem(&nilfs->ns_segctor_sem);
85 	nilfs->ns_sb_update_freq = NILFS_SB_FREQ;
86 
87 	return nilfs;
88 }
89 
90 /**
91  * destroy_nilfs - destroy nilfs object
92  * @nilfs: nilfs object to be released
93  */
destroy_nilfs(struct the_nilfs * nilfs)94 void destroy_nilfs(struct the_nilfs *nilfs)
95 {
96 	might_sleep();
97 	if (nilfs_init(nilfs)) {
98 		nilfs_sysfs_delete_device_group(nilfs);
99 		brelse(nilfs->ns_sbh[0]);
100 		brelse(nilfs->ns_sbh[1]);
101 	}
102 	kfree(nilfs);
103 }
104 
nilfs_load_super_root(struct the_nilfs * nilfs,struct super_block * sb,sector_t sr_block)105 static int nilfs_load_super_root(struct the_nilfs *nilfs,
106 				 struct super_block *sb, sector_t sr_block)
107 {
108 	struct buffer_head *bh_sr;
109 	struct nilfs_super_root *raw_sr;
110 	struct nilfs_super_block **sbp = nilfs->ns_sbp;
111 	struct nilfs_inode *rawi;
112 	unsigned int dat_entry_size, segment_usage_size, checkpoint_size;
113 	unsigned int inode_size;
114 	int err;
115 
116 	err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
117 	if (unlikely(err))
118 		return err;
119 
120 	down_read(&nilfs->ns_sem);
121 	dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
122 	checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
123 	segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
124 	up_read(&nilfs->ns_sem);
125 
126 	inode_size = nilfs->ns_inode_size;
127 
128 	rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
129 	err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
130 	if (err)
131 		goto failed;
132 
133 	rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
134 	err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
135 	if (err)
136 		goto failed_dat;
137 
138 	rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
139 	err = nilfs_sufile_read(sb, segment_usage_size, rawi,
140 				&nilfs->ns_sufile);
141 	if (err)
142 		goto failed_cpfile;
143 
144 	raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
145 	nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
146 
147  failed:
148 	brelse(bh_sr);
149 	return err;
150 
151  failed_cpfile:
152 	iput(nilfs->ns_cpfile);
153 
154  failed_dat:
155 	iput(nilfs->ns_dat);
156 	goto failed;
157 }
158 
nilfs_init_recovery_info(struct nilfs_recovery_info * ri)159 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
160 {
161 	memset(ri, 0, sizeof(*ri));
162 	INIT_LIST_HEAD(&ri->ri_used_segments);
163 }
164 
nilfs_clear_recovery_info(struct nilfs_recovery_info * ri)165 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
166 {
167 	nilfs_dispose_segment_list(&ri->ri_used_segments);
168 }
169 
170 /**
171  * nilfs_store_log_cursor - load log cursor from a super block
172  * @nilfs: nilfs object
173  * @sbp: buffer storing super block to be read
174  *
175  * nilfs_store_log_cursor() reads the last position of the log
176  * containing a super root from a given super block, and initializes
177  * relevant information on the nilfs object preparatory for log
178  * scanning and recovery.
179  */
nilfs_store_log_cursor(struct the_nilfs * nilfs,struct nilfs_super_block * sbp)180 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
181 				  struct nilfs_super_block *sbp)
182 {
183 	int ret = 0;
184 
185 	nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
186 	nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
187 	nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
188 
189 	nilfs->ns_prev_seq = nilfs->ns_last_seq;
190 	nilfs->ns_seg_seq = nilfs->ns_last_seq;
191 	nilfs->ns_segnum =
192 		nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
193 	nilfs->ns_cno = nilfs->ns_last_cno + 1;
194 	if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
195 		nilfs_msg(nilfs->ns_sb, KERN_ERR,
196 			  "pointed segment number is out of range: segnum=%llu, nsegments=%lu",
197 			  (unsigned long long)nilfs->ns_segnum,
198 			  nilfs->ns_nsegments);
199 		ret = -EINVAL;
200 	}
201 	return ret;
202 }
203 
204 /**
205  * load_nilfs - load and recover the nilfs
206  * @nilfs: the_nilfs structure to be released
207  * @sb: super block isntance used to recover past segment
208  *
209  * load_nilfs() searches and load the latest super root,
210  * attaches the last segment, and does recovery if needed.
211  * The caller must call this exclusively for simultaneous mounts.
212  */
load_nilfs(struct the_nilfs * nilfs,struct super_block * sb)213 int 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 		nilfs_msg(sb, KERN_WARNING, "mounting unchecked fs");
223 		if (s_flags & MS_RDONLY) {
224 			nilfs_msg(sb, KERN_INFO,
225 				  "recovery required for readonly filesystem");
226 			nilfs_msg(sb, KERN_INFO,
227 				  "write access will be enabled during recovery");
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 			nilfs_msg(sb, KERN_WARNING,
243 				  "unable to fall back to spare super block");
244 			goto scan_error;
245 		}
246 		nilfs_msg(sb, KERN_INFO,
247 			  "trying rollback from an earlier position");
248 
249 		/*
250 		 * restore super block with its spare and reconfigure
251 		 * relevant states of the nilfs object.
252 		 */
253 		memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
254 		nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
255 		nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
256 
257 		/* verify consistency between two super blocks */
258 		blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
259 		if (blocksize != nilfs->ns_blocksize) {
260 			nilfs_msg(sb, KERN_WARNING,
261 				  "blocksize differs between two super blocks (%d != %d)",
262 				  blocksize, nilfs->ns_blocksize);
263 			goto scan_error;
264 		}
265 
266 		err = nilfs_store_log_cursor(nilfs, sbp[0]);
267 		if (err)
268 			goto scan_error;
269 
270 		/* drop clean flag to allow roll-forward and recovery */
271 		nilfs->ns_mount_state &= ~NILFS_VALID_FS;
272 		valid_fs = 0;
273 
274 		err = nilfs_search_super_root(nilfs, &ri);
275 		if (err)
276 			goto scan_error;
277 	}
278 
279 	err = nilfs_load_super_root(nilfs, sb, ri.ri_super_root);
280 	if (unlikely(err)) {
281 		nilfs_msg(sb, KERN_ERR, "error %d while loading super root",
282 			  err);
283 		goto failed;
284 	}
285 
286 	if (valid_fs)
287 		goto skip_recovery;
288 
289 	if (s_flags & MS_RDONLY) {
290 		__u64 features;
291 
292 		if (nilfs_test_opt(nilfs, NORECOVERY)) {
293 			nilfs_msg(sb, KERN_INFO,
294 				  "norecovery option specified, skipping roll-forward recovery");
295 			goto skip_recovery;
296 		}
297 		features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
298 			~NILFS_FEATURE_COMPAT_RO_SUPP;
299 		if (features) {
300 			nilfs_msg(sb, KERN_ERR,
301 				  "couldn't proceed with recovery because of unsupported optional features (%llx)",
302 				  (unsigned long long)features);
303 			err = -EROFS;
304 			goto failed_unload;
305 		}
306 		if (really_read_only) {
307 			nilfs_msg(sb, KERN_ERR,
308 				  "write access unavailable, cannot proceed");
309 			err = -EROFS;
310 			goto failed_unload;
311 		}
312 		sb->s_flags &= ~MS_RDONLY;
313 	} else if (nilfs_test_opt(nilfs, NORECOVERY)) {
314 		nilfs_msg(sb, KERN_ERR,
315 			  "recovery cancelled because norecovery option was specified for a read/write mount");
316 		err = -EINVAL;
317 		goto failed_unload;
318 	}
319 
320 	err = nilfs_salvage_orphan_logs(nilfs, sb, &ri);
321 	if (err)
322 		goto failed_unload;
323 
324 	down_write(&nilfs->ns_sem);
325 	nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
326 	err = nilfs_cleanup_super(sb);
327 	up_write(&nilfs->ns_sem);
328 
329 	if (err) {
330 		nilfs_msg(sb, KERN_ERR,
331 			  "error %d updating super block. recovery unfinished.",
332 			  err);
333 		goto failed_unload;
334 	}
335 	nilfs_msg(sb, KERN_INFO, "recovery complete");
336 
337  skip_recovery:
338 	nilfs_clear_recovery_info(&ri);
339 	sb->s_flags = s_flags;
340 	return 0;
341 
342  scan_error:
343 	nilfs_msg(sb, KERN_ERR, "error %d while searching super root", err);
344 	goto failed;
345 
346  failed_unload:
347 	iput(nilfs->ns_cpfile);
348 	iput(nilfs->ns_sufile);
349 	iput(nilfs->ns_dat);
350 
351  failed:
352 	nilfs_clear_recovery_info(&ri);
353 	sb->s_flags = s_flags;
354 	return err;
355 }
356 
nilfs_max_size(unsigned int blkbits)357 static unsigned long long nilfs_max_size(unsigned int blkbits)
358 {
359 	unsigned int max_bits;
360 	unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
361 
362 	max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
363 	if (max_bits < 64)
364 		res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
365 	return res;
366 }
367 
368 /**
369  * nilfs_nrsvsegs - calculate the number of reserved segments
370  * @nilfs: nilfs object
371  * @nsegs: total number of segments
372  */
nilfs_nrsvsegs(struct the_nilfs * nilfs,unsigned long nsegs)373 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
374 {
375 	return max_t(unsigned long, NILFS_MIN_NRSVSEGS,
376 		     DIV_ROUND_UP(nsegs * nilfs->ns_r_segments_percentage,
377 				  100));
378 }
379 
nilfs_set_nsegments(struct the_nilfs * nilfs,unsigned long nsegs)380 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs)
381 {
382 	nilfs->ns_nsegments = nsegs;
383 	nilfs->ns_nrsvsegs = nilfs_nrsvsegs(nilfs, nsegs);
384 }
385 
nilfs_store_disk_layout(struct the_nilfs * nilfs,struct nilfs_super_block * sbp)386 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
387 				   struct nilfs_super_block *sbp)
388 {
389 	if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
390 		nilfs_msg(nilfs->ns_sb, KERN_ERR,
391 			  "unsupported revision (superblock rev.=%d.%d, current rev.=%d.%d). Please check the version of mkfs.nilfs(2).",
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 	if (nilfs->ns_inode_size > nilfs->ns_blocksize) {
403 		nilfs_msg(nilfs->ns_sb, KERN_ERR,
404 			  "too large inode size: %d bytes",
405 			  nilfs->ns_inode_size);
406 		return -EINVAL;
407 	} else if (nilfs->ns_inode_size < NILFS_MIN_INODE_SIZE) {
408 		nilfs_msg(nilfs->ns_sb, KERN_ERR,
409 			  "too small inode size: %d bytes",
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 		nilfs_msg(nilfs->ns_sb, KERN_ERR,
419 			  "too short segment: %lu blocks",
420 			  nilfs->ns_blocks_per_segment);
421 		return -EINVAL;
422 	}
423 
424 	nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
425 	nilfs->ns_r_segments_percentage =
426 		le32_to_cpu(sbp->s_r_segments_percentage);
427 	if (nilfs->ns_r_segments_percentage < 1 ||
428 	    nilfs->ns_r_segments_percentage > 99) {
429 		nilfs_msg(nilfs->ns_sb, KERN_ERR,
430 			  "invalid reserved segments percentage: %lu",
431 			  nilfs->ns_r_segments_percentage);
432 		return -EINVAL;
433 	}
434 
435 	nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments));
436 	nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
437 	return 0;
438 }
439 
nilfs_valid_sb(struct nilfs_super_block * sbp)440 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
441 {
442 	static unsigned char sum[4];
443 	const int sumoff = offsetof(struct nilfs_super_block, s_sum);
444 	size_t bytes;
445 	u32 crc;
446 
447 	if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
448 		return 0;
449 	bytes = le16_to_cpu(sbp->s_bytes);
450 	if (bytes < sumoff + 4 || bytes > BLOCK_SIZE)
451 		return 0;
452 	crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
453 		       sumoff);
454 	crc = crc32_le(crc, sum, 4);
455 	crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
456 		       bytes - sumoff - 4);
457 	return crc == le32_to_cpu(sbp->s_sum);
458 }
459 
nilfs_sb2_bad_offset(struct nilfs_super_block * sbp,u64 offset)460 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
461 {
462 	return offset < ((le64_to_cpu(sbp->s_nsegments) *
463 			  le32_to_cpu(sbp->s_blocks_per_segment)) <<
464 			 (le32_to_cpu(sbp->s_log_block_size) + 10));
465 }
466 
nilfs_release_super_block(struct the_nilfs * nilfs)467 static void nilfs_release_super_block(struct the_nilfs *nilfs)
468 {
469 	int i;
470 
471 	for (i = 0; i < 2; i++) {
472 		if (nilfs->ns_sbp[i]) {
473 			brelse(nilfs->ns_sbh[i]);
474 			nilfs->ns_sbh[i] = NULL;
475 			nilfs->ns_sbp[i] = NULL;
476 		}
477 	}
478 }
479 
nilfs_fall_back_super_block(struct the_nilfs * nilfs)480 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
481 {
482 	brelse(nilfs->ns_sbh[0]);
483 	nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
484 	nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
485 	nilfs->ns_sbh[1] = NULL;
486 	nilfs->ns_sbp[1] = NULL;
487 }
488 
nilfs_swap_super_block(struct the_nilfs * nilfs)489 void nilfs_swap_super_block(struct the_nilfs *nilfs)
490 {
491 	struct buffer_head *tsbh = nilfs->ns_sbh[0];
492 	struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
493 
494 	nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
495 	nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
496 	nilfs->ns_sbh[1] = tsbh;
497 	nilfs->ns_sbp[1] = tsbp;
498 }
499 
nilfs_load_super_block(struct the_nilfs * nilfs,struct super_block * sb,int blocksize,struct nilfs_super_block ** sbpp)500 static int nilfs_load_super_block(struct the_nilfs *nilfs,
501 				  struct super_block *sb, int blocksize,
502 				  struct nilfs_super_block **sbpp)
503 {
504 	struct nilfs_super_block **sbp = nilfs->ns_sbp;
505 	struct buffer_head **sbh = nilfs->ns_sbh;
506 	u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
507 	int valid[2], swp = 0;
508 
509 	sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
510 					&sbh[0]);
511 	sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
512 
513 	if (!sbp[0]) {
514 		if (!sbp[1]) {
515 			nilfs_msg(sb, KERN_ERR, "unable to read superblock");
516 			return -EIO;
517 		}
518 		nilfs_msg(sb, KERN_WARNING,
519 			  "unable to read primary superblock (blocksize = %d)",
520 			  blocksize);
521 	} else if (!sbp[1]) {
522 		nilfs_msg(sb, KERN_WARNING,
523 			  "unable to read secondary superblock (blocksize = %d)",
524 			  blocksize);
525 	}
526 
527 	/*
528 	 * Compare two super blocks and set 1 in swp if the secondary
529 	 * super block is valid and newer.  Otherwise, set 0 in swp.
530 	 */
531 	valid[0] = nilfs_valid_sb(sbp[0]);
532 	valid[1] = nilfs_valid_sb(sbp[1]);
533 	swp = valid[1] && (!valid[0] ||
534 			   le64_to_cpu(sbp[1]->s_last_cno) >
535 			   le64_to_cpu(sbp[0]->s_last_cno));
536 
537 	if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
538 		brelse(sbh[1]);
539 		sbh[1] = NULL;
540 		sbp[1] = NULL;
541 		valid[1] = 0;
542 		swp = 0;
543 	}
544 	if (!valid[swp]) {
545 		nilfs_release_super_block(nilfs);
546 		nilfs_msg(sb, KERN_ERR, "couldn't find nilfs on the device");
547 		return -EINVAL;
548 	}
549 
550 	if (!valid[!swp])
551 		nilfs_msg(sb, KERN_WARNING,
552 			  "broken superblock, retrying with spare superblock (blocksize = %d)",
553 			  blocksize);
554 	if (swp)
555 		nilfs_swap_super_block(nilfs);
556 
557 	nilfs->ns_sbwcount = 0;
558 	nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
559 	nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
560 	*sbpp = sbp[0];
561 	return 0;
562 }
563 
564 /**
565  * init_nilfs - initialize a NILFS instance.
566  * @nilfs: the_nilfs structure
567  * @sb: super block
568  * @data: mount options
569  *
570  * init_nilfs() performs common initialization per block device (e.g.
571  * reading the super block, getting disk layout information, initializing
572  * shared fields in the_nilfs).
573  *
574  * Return Value: On success, 0 is returned. On error, a negative error
575  * code is returned.
576  */
init_nilfs(struct the_nilfs * nilfs,struct super_block * sb,char * data)577 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
578 {
579 	struct nilfs_super_block *sbp;
580 	int blocksize;
581 	int err;
582 
583 	down_write(&nilfs->ns_sem);
584 
585 	blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
586 	if (!blocksize) {
587 		nilfs_msg(sb, KERN_ERR, "unable to set blocksize");
588 		err = -EINVAL;
589 		goto out;
590 	}
591 	err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
592 	if (err)
593 		goto out;
594 
595 	err = nilfs_store_magic_and_option(sb, sbp, data);
596 	if (err)
597 		goto failed_sbh;
598 
599 	err = nilfs_check_feature_compatibility(sb, sbp);
600 	if (err)
601 		goto failed_sbh;
602 
603 	blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
604 	if (blocksize < NILFS_MIN_BLOCK_SIZE ||
605 	    blocksize > NILFS_MAX_BLOCK_SIZE) {
606 		nilfs_msg(sb, KERN_ERR,
607 			  "couldn't mount because of unsupported filesystem blocksize %d",
608 			  blocksize);
609 		err = -EINVAL;
610 		goto failed_sbh;
611 	}
612 	if (sb->s_blocksize != blocksize) {
613 		int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
614 
615 		if (blocksize < hw_blocksize) {
616 			nilfs_msg(sb, KERN_ERR,
617 				  "blocksize %d too small for device (sector-size = %d)",
618 				  blocksize, hw_blocksize);
619 			err = -EINVAL;
620 			goto failed_sbh;
621 		}
622 		nilfs_release_super_block(nilfs);
623 		sb_set_blocksize(sb, blocksize);
624 
625 		err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
626 		if (err)
627 			goto out;
628 			/*
629 			 * Not to failed_sbh; sbh is released automatically
630 			 * when reloading fails.
631 			 */
632 	}
633 	nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
634 	nilfs->ns_blocksize = blocksize;
635 
636 	get_random_bytes(&nilfs->ns_next_generation,
637 			 sizeof(nilfs->ns_next_generation));
638 
639 	err = nilfs_store_disk_layout(nilfs, sbp);
640 	if (err)
641 		goto failed_sbh;
642 
643 	sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
644 
645 	nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
646 
647 	err = nilfs_store_log_cursor(nilfs, sbp);
648 	if (err)
649 		goto failed_sbh;
650 
651 	err = nilfs_sysfs_create_device_group(sb);
652 	if (err)
653 		goto failed_sbh;
654 
655 	set_nilfs_init(nilfs);
656 	err = 0;
657  out:
658 	up_write(&nilfs->ns_sem);
659 	return err;
660 
661  failed_sbh:
662 	nilfs_release_super_block(nilfs);
663 	goto out;
664 }
665 
nilfs_discard_segments(struct the_nilfs * nilfs,__u64 * segnump,size_t nsegs)666 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
667 			    size_t nsegs)
668 {
669 	sector_t seg_start, seg_end;
670 	sector_t start = 0, nblocks = 0;
671 	unsigned int sects_per_block;
672 	__u64 *sn;
673 	int ret = 0;
674 
675 	sects_per_block = (1 << nilfs->ns_blocksize_bits) /
676 		bdev_logical_block_size(nilfs->ns_bdev);
677 	for (sn = segnump; sn < segnump + nsegs; sn++) {
678 		nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
679 
680 		if (!nblocks) {
681 			start = seg_start;
682 			nblocks = seg_end - seg_start + 1;
683 		} else if (start + nblocks == seg_start) {
684 			nblocks += seg_end - seg_start + 1;
685 		} else {
686 			ret = blkdev_issue_discard(nilfs->ns_bdev,
687 						   start * sects_per_block,
688 						   nblocks * sects_per_block,
689 						   GFP_NOFS, 0);
690 			if (ret < 0)
691 				return ret;
692 			nblocks = 0;
693 		}
694 	}
695 	if (nblocks)
696 		ret = blkdev_issue_discard(nilfs->ns_bdev,
697 					   start * sects_per_block,
698 					   nblocks * sects_per_block,
699 					   GFP_NOFS, 0);
700 	return ret;
701 }
702 
nilfs_count_free_blocks(struct the_nilfs * nilfs,sector_t * nblocks)703 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
704 {
705 	unsigned long ncleansegs;
706 
707 	down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
708 	ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
709 	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
710 	*nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
711 	return 0;
712 }
713 
nilfs_near_disk_full(struct the_nilfs * nilfs)714 int nilfs_near_disk_full(struct the_nilfs *nilfs)
715 {
716 	unsigned long ncleansegs, nincsegs;
717 
718 	ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
719 	nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
720 		nilfs->ns_blocks_per_segment + 1;
721 
722 	return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
723 }
724 
nilfs_lookup_root(struct the_nilfs * nilfs,__u64 cno)725 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
726 {
727 	struct rb_node *n;
728 	struct nilfs_root *root;
729 
730 	spin_lock(&nilfs->ns_cptree_lock);
731 	n = nilfs->ns_cptree.rb_node;
732 	while (n) {
733 		root = rb_entry(n, struct nilfs_root, rb_node);
734 
735 		if (cno < root->cno) {
736 			n = n->rb_left;
737 		} else if (cno > root->cno) {
738 			n = n->rb_right;
739 		} else {
740 			atomic_inc(&root->count);
741 			spin_unlock(&nilfs->ns_cptree_lock);
742 			return root;
743 		}
744 	}
745 	spin_unlock(&nilfs->ns_cptree_lock);
746 
747 	return NULL;
748 }
749 
750 struct nilfs_root *
nilfs_find_or_create_root(struct the_nilfs * nilfs,__u64 cno)751 nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
752 {
753 	struct rb_node **p, *parent;
754 	struct nilfs_root *root, *new;
755 	int err;
756 
757 	root = nilfs_lookup_root(nilfs, cno);
758 	if (root)
759 		return root;
760 
761 	new = kzalloc(sizeof(*root), GFP_KERNEL);
762 	if (!new)
763 		return NULL;
764 
765 	spin_lock(&nilfs->ns_cptree_lock);
766 
767 	p = &nilfs->ns_cptree.rb_node;
768 	parent = NULL;
769 
770 	while (*p) {
771 		parent = *p;
772 		root = rb_entry(parent, struct nilfs_root, rb_node);
773 
774 		if (cno < root->cno) {
775 			p = &(*p)->rb_left;
776 		} else if (cno > root->cno) {
777 			p = &(*p)->rb_right;
778 		} else {
779 			atomic_inc(&root->count);
780 			spin_unlock(&nilfs->ns_cptree_lock);
781 			kfree(new);
782 			return root;
783 		}
784 	}
785 
786 	new->cno = cno;
787 	new->ifile = NULL;
788 	new->nilfs = nilfs;
789 	atomic_set(&new->count, 1);
790 	atomic64_set(&new->inodes_count, 0);
791 	atomic64_set(&new->blocks_count, 0);
792 
793 	rb_link_node(&new->rb_node, parent, p);
794 	rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
795 
796 	spin_unlock(&nilfs->ns_cptree_lock);
797 
798 	err = nilfs_sysfs_create_snapshot_group(new);
799 	if (err) {
800 		kfree(new);
801 		new = NULL;
802 	}
803 
804 	return new;
805 }
806 
nilfs_put_root(struct nilfs_root * root)807 void nilfs_put_root(struct nilfs_root *root)
808 {
809 	if (atomic_dec_and_test(&root->count)) {
810 		struct the_nilfs *nilfs = root->nilfs;
811 
812 		nilfs_sysfs_delete_snapshot_group(root);
813 
814 		spin_lock(&nilfs->ns_cptree_lock);
815 		rb_erase(&root->rb_node, &nilfs->ns_cptree);
816 		spin_unlock(&nilfs->ns_cptree_lock);
817 		iput(root->ifile);
818 
819 		kfree(root);
820 	}
821 }
822