nilfs2: remove individual gfp constants for each metadata file
[linux-2.6.git] / fs / nilfs2 / the_nilfs.c
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  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
19  *
20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
21  *
22  */
23
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/crc32.h>
29 #include "nilfs.h"
30 #include "segment.h"
31 #include "alloc.h"
32 #include "cpfile.h"
33 #include "sufile.h"
34 #include "dat.h"
35 #include "segbuf.h"
36
37
38 static LIST_HEAD(nilfs_objects);
39 static DEFINE_SPINLOCK(nilfs_lock);
40
41 void 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         spin_unlock(&nilfs->ns_last_segment_lock);
49 }
50
51 /**
52  * alloc_nilfs - allocate the_nilfs structure
53  * @bdev: block device to which the_nilfs is related
54  *
55  * alloc_nilfs() allocates memory for the_nilfs and
56  * initializes its reference count and locks.
57  *
58  * Return Value: On success, pointer to the_nilfs is returned.
59  * On error, NULL is returned.
60  */
61 static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
62 {
63         struct the_nilfs *nilfs;
64
65         nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
66         if (!nilfs)
67                 return NULL;
68
69         nilfs->ns_bdev = bdev;
70         atomic_set(&nilfs->ns_count, 1);
71         atomic_set(&nilfs->ns_ndirtyblks, 0);
72         init_rwsem(&nilfs->ns_sem);
73         init_rwsem(&nilfs->ns_super_sem);
74         mutex_init(&nilfs->ns_mount_mutex);
75         init_rwsem(&nilfs->ns_writer_sem);
76         INIT_LIST_HEAD(&nilfs->ns_list);
77         INIT_LIST_HEAD(&nilfs->ns_supers);
78         spin_lock_init(&nilfs->ns_last_segment_lock);
79         nilfs->ns_gc_inodes_h = NULL;
80         init_rwsem(&nilfs->ns_segctor_sem);
81
82         return nilfs;
83 }
84
85 /**
86  * find_or_create_nilfs - find or create nilfs object
87  * @bdev: block device to which the_nilfs is related
88  *
89  * find_nilfs() looks up an existent nilfs object created on the
90  * device and gets the reference count of the object.  If no nilfs object
91  * is found on the device, a new nilfs object is allocated.
92  *
93  * Return Value: On success, pointer to the nilfs object is returned.
94  * On error, NULL is returned.
95  */
96 struct the_nilfs *find_or_create_nilfs(struct block_device *bdev)
97 {
98         struct the_nilfs *nilfs, *new = NULL;
99
100  retry:
101         spin_lock(&nilfs_lock);
102         list_for_each_entry(nilfs, &nilfs_objects, ns_list) {
103                 if (nilfs->ns_bdev == bdev) {
104                         get_nilfs(nilfs);
105                         spin_unlock(&nilfs_lock);
106                         if (new)
107                                 put_nilfs(new);
108                         return nilfs; /* existing object */
109                 }
110         }
111         if (new) {
112                 list_add_tail(&new->ns_list, &nilfs_objects);
113                 spin_unlock(&nilfs_lock);
114                 return new; /* new object */
115         }
116         spin_unlock(&nilfs_lock);
117
118         new = alloc_nilfs(bdev);
119         if (new)
120                 goto retry;
121         return NULL; /* insufficient memory */
122 }
123
124 /**
125  * put_nilfs - release a reference to the_nilfs
126  * @nilfs: the_nilfs structure to be released
127  *
128  * put_nilfs() decrements a reference counter of the_nilfs.
129  * If the reference count reaches zero, the_nilfs is freed.
130  */
131 void put_nilfs(struct the_nilfs *nilfs)
132 {
133         spin_lock(&nilfs_lock);
134         if (!atomic_dec_and_test(&nilfs->ns_count)) {
135                 spin_unlock(&nilfs_lock);
136                 return;
137         }
138         list_del_init(&nilfs->ns_list);
139         spin_unlock(&nilfs_lock);
140
141         /*
142          * Increment of ns_count never occurs below because the caller
143          * of get_nilfs() holds at least one reference to the_nilfs.
144          * Thus its exclusion control is not required here.
145          */
146
147         might_sleep();
148         if (nilfs_loaded(nilfs)) {
149                 nilfs_mdt_clear(nilfs->ns_sufile);
150                 nilfs_mdt_destroy(nilfs->ns_sufile);
151                 nilfs_mdt_clear(nilfs->ns_cpfile);
152                 nilfs_mdt_destroy(nilfs->ns_cpfile);
153                 nilfs_mdt_clear(nilfs->ns_dat);
154                 nilfs_mdt_destroy(nilfs->ns_dat);
155                 /* XXX: how and when to clear nilfs->ns_gc_dat? */
156                 nilfs_mdt_destroy(nilfs->ns_gc_dat);
157         }
158         if (nilfs_init(nilfs)) {
159                 nilfs_destroy_gccache(nilfs);
160                 brelse(nilfs->ns_sbh[0]);
161                 brelse(nilfs->ns_sbh[1]);
162         }
163         kfree(nilfs);
164 }
165
166 static int nilfs_load_super_root(struct the_nilfs *nilfs,
167                                  struct nilfs_sb_info *sbi, sector_t sr_block)
168 {
169         static struct lock_class_key dat_lock_key;
170         struct buffer_head *bh_sr;
171         struct nilfs_super_root *raw_sr;
172         struct nilfs_super_block **sbp = nilfs->ns_sbp;
173         unsigned dat_entry_size, segment_usage_size, checkpoint_size;
174         unsigned inode_size;
175         int err;
176
177         err = nilfs_read_super_root_block(sbi->s_super, sr_block, &bh_sr, 1);
178         if (unlikely(err))
179                 return err;
180
181         down_read(&nilfs->ns_sem);
182         dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
183         checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
184         segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
185         up_read(&nilfs->ns_sem);
186
187         inode_size = nilfs->ns_inode_size;
188
189         err = -ENOMEM;
190         nilfs->ns_dat = nilfs_mdt_new(nilfs, NULL, NILFS_DAT_INO);
191         if (unlikely(!nilfs->ns_dat))
192                 goto failed;
193
194         nilfs->ns_gc_dat = nilfs_mdt_new(nilfs, NULL, NILFS_DAT_INO);
195         if (unlikely(!nilfs->ns_gc_dat))
196                 goto failed_dat;
197
198         nilfs->ns_cpfile = nilfs_mdt_new(nilfs, NULL, NILFS_CPFILE_INO);
199         if (unlikely(!nilfs->ns_cpfile))
200                 goto failed_gc_dat;
201
202         nilfs->ns_sufile = nilfs_mdt_new(nilfs, NULL, NILFS_SUFILE_INO);
203         if (unlikely(!nilfs->ns_sufile))
204                 goto failed_cpfile;
205
206         err = nilfs_palloc_init_blockgroup(nilfs->ns_dat, dat_entry_size);
207         if (unlikely(err))
208                 goto failed_sufile;
209
210         err = nilfs_palloc_init_blockgroup(nilfs->ns_gc_dat, dat_entry_size);
211         if (unlikely(err))
212                 goto failed_sufile;
213
214         lockdep_set_class(&NILFS_MDT(nilfs->ns_dat)->mi_sem, &dat_lock_key);
215         lockdep_set_class(&NILFS_MDT(nilfs->ns_gc_dat)->mi_sem, &dat_lock_key);
216
217         nilfs_mdt_set_shadow(nilfs->ns_dat, nilfs->ns_gc_dat);
218         nilfs_mdt_set_entry_size(nilfs->ns_cpfile, checkpoint_size,
219                                  sizeof(struct nilfs_cpfile_header));
220         nilfs_mdt_set_entry_size(nilfs->ns_sufile, segment_usage_size,
221                                  sizeof(struct nilfs_sufile_header));
222
223         err = nilfs_mdt_read_inode_direct(
224                 nilfs->ns_dat, bh_sr, NILFS_SR_DAT_OFFSET(inode_size));
225         if (unlikely(err))
226                 goto failed_sufile;
227
228         err = nilfs_mdt_read_inode_direct(
229                 nilfs->ns_cpfile, bh_sr, NILFS_SR_CPFILE_OFFSET(inode_size));
230         if (unlikely(err))
231                 goto failed_sufile;
232
233         err = nilfs_mdt_read_inode_direct(
234                 nilfs->ns_sufile, bh_sr, NILFS_SR_SUFILE_OFFSET(inode_size));
235         if (unlikely(err))
236                 goto failed_sufile;
237
238         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
239         nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
240
241  failed:
242         brelse(bh_sr);
243         return err;
244
245  failed_sufile:
246         nilfs_mdt_destroy(nilfs->ns_sufile);
247
248  failed_cpfile:
249         nilfs_mdt_destroy(nilfs->ns_cpfile);
250
251  failed_gc_dat:
252         nilfs_mdt_destroy(nilfs->ns_gc_dat);
253
254  failed_dat:
255         nilfs_mdt_destroy(nilfs->ns_dat);
256         goto failed;
257 }
258
259 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
260 {
261         memset(ri, 0, sizeof(*ri));
262         INIT_LIST_HEAD(&ri->ri_used_segments);
263 }
264
265 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
266 {
267         nilfs_dispose_segment_list(&ri->ri_used_segments);
268 }
269
270 /**
271  * load_nilfs - load and recover the nilfs
272  * @nilfs: the_nilfs structure to be released
273  * @sbi: nilfs_sb_info used to recover past segment
274  *
275  * load_nilfs() searches and load the latest super root,
276  * attaches the last segment, and does recovery if needed.
277  * The caller must call this exclusively for simultaneous mounts.
278  */
279 int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
280 {
281         struct nilfs_recovery_info ri;
282         unsigned int s_flags = sbi->s_super->s_flags;
283         int really_read_only = bdev_read_only(nilfs->ns_bdev);
284         unsigned valid_fs;
285         int err = 0;
286
287         nilfs_init_recovery_info(&ri);
288
289         down_write(&nilfs->ns_sem);
290         valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
291         up_write(&nilfs->ns_sem);
292
293         if (!valid_fs && (s_flags & MS_RDONLY)) {
294                 printk(KERN_INFO "NILFS: INFO: recovery "
295                        "required for readonly filesystem.\n");
296                 if (really_read_only) {
297                         printk(KERN_ERR "NILFS: write access "
298                                "unavailable, cannot proceed.\n");
299                         err = -EROFS;
300                         goto failed;
301                 }
302                 printk(KERN_INFO "NILFS: write access will "
303                        "be enabled during recovery.\n");
304                 sbi->s_super->s_flags &= ~MS_RDONLY;
305         }
306
307         err = nilfs_search_super_root(nilfs, sbi, &ri);
308         if (unlikely(err)) {
309                 printk(KERN_ERR "NILFS: error searching super root.\n");
310                 goto failed;
311         }
312
313         err = nilfs_load_super_root(nilfs, sbi, ri.ri_super_root);
314         if (unlikely(err)) {
315                 printk(KERN_ERR "NILFS: error loading super root.\n");
316                 goto failed;
317         }
318
319         if (!valid_fs) {
320                 err = nilfs_recover_logical_segments(nilfs, sbi, &ri);
321                 if (unlikely(err)) {
322                         nilfs_mdt_destroy(nilfs->ns_cpfile);
323                         nilfs_mdt_destroy(nilfs->ns_sufile);
324                         nilfs_mdt_destroy(nilfs->ns_dat);
325                         goto failed;
326                 }
327                 if (ri.ri_need_recovery == NILFS_RECOVERY_SR_UPDATED)
328                         sbi->s_super->s_dirt = 1;
329         }
330
331         set_nilfs_loaded(nilfs);
332
333  failed:
334         nilfs_clear_recovery_info(&ri);
335         sbi->s_super->s_flags = s_flags;
336         return err;
337 }
338
339 static unsigned long long nilfs_max_size(unsigned int blkbits)
340 {
341         unsigned int max_bits;
342         unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
343
344         max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
345         if (max_bits < 64)
346                 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
347         return res;
348 }
349
350 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
351                                    struct nilfs_super_block *sbp)
352 {
353         if (le32_to_cpu(sbp->s_rev_level) != NILFS_CURRENT_REV) {
354                 printk(KERN_ERR "NILFS: revision mismatch "
355                        "(superblock rev.=%d.%d, current rev.=%d.%d). "
356                        "Please check the version of mkfs.nilfs.\n",
357                        le32_to_cpu(sbp->s_rev_level),
358                        le16_to_cpu(sbp->s_minor_rev_level),
359                        NILFS_CURRENT_REV, NILFS_MINOR_REV);
360                 return -EINVAL;
361         }
362         nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
363         if (nilfs->ns_sbsize > BLOCK_SIZE)
364                 return -EINVAL;
365
366         nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
367         nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
368
369         nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
370         if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
371                 printk(KERN_ERR "NILFS: too short segment. \n");
372                 return -EINVAL;
373         }
374
375         nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
376         nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
377         nilfs->ns_r_segments_percentage =
378                 le32_to_cpu(sbp->s_r_segments_percentage);
379         nilfs->ns_nrsvsegs =
380                 max_t(unsigned long, NILFS_MIN_NRSVSEGS,
381                       DIV_ROUND_UP(nilfs->ns_nsegments *
382                                    nilfs->ns_r_segments_percentage, 100));
383         nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
384         return 0;
385 }
386
387 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
388 {
389         static unsigned char sum[4];
390         const int sumoff = offsetof(struct nilfs_super_block, s_sum);
391         size_t bytes;
392         u32 crc;
393
394         if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
395                 return 0;
396         bytes = le16_to_cpu(sbp->s_bytes);
397         if (bytes > BLOCK_SIZE)
398                 return 0;
399         crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
400                        sumoff);
401         crc = crc32_le(crc, sum, 4);
402         crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
403                        bytes - sumoff - 4);
404         return crc == le32_to_cpu(sbp->s_sum);
405 }
406
407 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
408 {
409         return offset < ((le64_to_cpu(sbp->s_nsegments) *
410                           le32_to_cpu(sbp->s_blocks_per_segment)) <<
411                          (le32_to_cpu(sbp->s_log_block_size) + 10));
412 }
413
414 static void nilfs_release_super_block(struct the_nilfs *nilfs)
415 {
416         int i;
417
418         for (i = 0; i < 2; i++) {
419                 if (nilfs->ns_sbp[i]) {
420                         brelse(nilfs->ns_sbh[i]);
421                         nilfs->ns_sbh[i] = NULL;
422                         nilfs->ns_sbp[i] = NULL;
423                 }
424         }
425 }
426
427 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
428 {
429         brelse(nilfs->ns_sbh[0]);
430         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
431         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
432         nilfs->ns_sbh[1] = NULL;
433         nilfs->ns_sbp[1] = NULL;
434 }
435
436 void nilfs_swap_super_block(struct the_nilfs *nilfs)
437 {
438         struct buffer_head *tsbh = nilfs->ns_sbh[0];
439         struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
440
441         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
442         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
443         nilfs->ns_sbh[1] = tsbh;
444         nilfs->ns_sbp[1] = tsbp;
445 }
446
447 static int nilfs_load_super_block(struct the_nilfs *nilfs,
448                                   struct super_block *sb, int blocksize,
449                                   struct nilfs_super_block **sbpp)
450 {
451         struct nilfs_super_block **sbp = nilfs->ns_sbp;
452         struct buffer_head **sbh = nilfs->ns_sbh;
453         u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
454         int valid[2], swp = 0;
455
456         sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
457                                         &sbh[0]);
458         sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
459
460         if (!sbp[0]) {
461                 if (!sbp[1]) {
462                         printk(KERN_ERR "NILFS: unable to read superblock\n");
463                         return -EIO;
464                 }
465                 printk(KERN_WARNING
466                        "NILFS warning: unable to read primary superblock\n");
467         } else if (!sbp[1])
468                 printk(KERN_WARNING
469                        "NILFS warning: unable to read secondary superblock\n");
470
471         valid[0] = nilfs_valid_sb(sbp[0]);
472         valid[1] = nilfs_valid_sb(sbp[1]);
473         swp = valid[1] &&
474                 (!valid[0] ||
475                  le64_to_cpu(sbp[1]->s_wtime) > le64_to_cpu(sbp[0]->s_wtime));
476
477         if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
478                 brelse(sbh[1]);
479                 sbh[1] = NULL;
480                 sbp[1] = NULL;
481                 swp = 0;
482         }
483         if (!valid[swp]) {
484                 nilfs_release_super_block(nilfs);
485                 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
486                        sb->s_id);
487                 return -EINVAL;
488         }
489
490         if (swp) {
491                 printk(KERN_WARNING "NILFS warning: broken superblock. "
492                        "using spare superblock.\n");
493                 nilfs_swap_super_block(nilfs);
494         }
495
496         nilfs->ns_sbwtime[0] = le64_to_cpu(sbp[0]->s_wtime);
497         nilfs->ns_sbwtime[1] = valid[!swp] ? le64_to_cpu(sbp[1]->s_wtime) : 0;
498         nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
499         *sbpp = sbp[0];
500         return 0;
501 }
502
503 /**
504  * init_nilfs - initialize a NILFS instance.
505  * @nilfs: the_nilfs structure
506  * @sbi: nilfs_sb_info
507  * @sb: super block
508  * @data: mount options
509  *
510  * init_nilfs() performs common initialization per block device (e.g.
511  * reading the super block, getting disk layout information, initializing
512  * shared fields in the_nilfs). It takes on some portion of the jobs
513  * typically done by a fill_super() routine. This division arises from
514  * the nature that multiple NILFS instances may be simultaneously
515  * mounted on a device.
516  * For multiple mounts on the same device, only the first mount
517  * invokes these tasks.
518  *
519  * Return Value: On success, 0 is returned. On error, a negative error
520  * code is returned.
521  */
522 int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
523 {
524         struct super_block *sb = sbi->s_super;
525         struct nilfs_super_block *sbp;
526         struct backing_dev_info *bdi;
527         int blocksize;
528         int err;
529
530         down_write(&nilfs->ns_sem);
531         if (nilfs_init(nilfs)) {
532                 /* Load values from existing the_nilfs */
533                 sbp = nilfs->ns_sbp[0];
534                 err = nilfs_store_magic_and_option(sb, sbp, data);
535                 if (err)
536                         goto out;
537
538                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
539                 if (sb->s_blocksize != blocksize &&
540                     !sb_set_blocksize(sb, blocksize)) {
541                         printk(KERN_ERR "NILFS: blocksize %d unfit to device\n",
542                                blocksize);
543                         err = -EINVAL;
544                 }
545                 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
546                 goto out;
547         }
548
549         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
550         if (!blocksize) {
551                 printk(KERN_ERR "NILFS: unable to set blocksize\n");
552                 err = -EINVAL;
553                 goto out;
554         }
555         err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
556         if (err)
557                 goto out;
558
559         err = nilfs_store_magic_and_option(sb, sbp, data);
560         if (err)
561                 goto failed_sbh;
562
563         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
564         if (sb->s_blocksize != blocksize) {
565                 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
566
567                 if (blocksize < hw_blocksize) {
568                         printk(KERN_ERR
569                                "NILFS: blocksize %d too small for device "
570                                "(sector-size = %d).\n",
571                                blocksize, hw_blocksize);
572                         err = -EINVAL;
573                         goto failed_sbh;
574                 }
575                 nilfs_release_super_block(nilfs);
576                 sb_set_blocksize(sb, blocksize);
577
578                 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
579                 if (err)
580                         goto out;
581                         /* not failed_sbh; sbh is released automatically
582                            when reloading fails. */
583         }
584         nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
585
586         err = nilfs_store_disk_layout(nilfs, sbp);
587         if (err)
588                 goto failed_sbh;
589
590         sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
591
592         nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
593
594         bdi = nilfs->ns_bdev->bd_inode_backing_dev_info;
595         if (!bdi)
596                 bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info;
597         nilfs->ns_bdi = bdi ? : &default_backing_dev_info;
598
599         /* Finding last segment */
600         nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
601         nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
602         nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
603
604         nilfs->ns_seg_seq = nilfs->ns_last_seq;
605         nilfs->ns_segnum =
606                 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
607         nilfs->ns_cno = nilfs->ns_last_cno + 1;
608         if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
609                 printk(KERN_ERR "NILFS invalid last segment number.\n");
610                 err = -EINVAL;
611                 goto failed_sbh;
612         }
613         /* Dummy values  */
614         nilfs->ns_free_segments_count =
615                 nilfs->ns_nsegments - (nilfs->ns_segnum + 1);
616
617         /* Initialize gcinode cache */
618         err = nilfs_init_gccache(nilfs);
619         if (err)
620                 goto failed_sbh;
621
622         set_nilfs_init(nilfs);
623         err = 0;
624  out:
625         up_write(&nilfs->ns_sem);
626         return err;
627
628  failed_sbh:
629         nilfs_release_super_block(nilfs);
630         goto out;
631 }
632
633 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
634 {
635         struct inode *dat = nilfs_dat_inode(nilfs);
636         unsigned long ncleansegs;
637         int err;
638
639         down_read(&NILFS_MDT(dat)->mi_sem);     /* XXX */
640         err = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile, &ncleansegs);
641         up_read(&NILFS_MDT(dat)->mi_sem);       /* XXX */
642         if (likely(!err))
643                 *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
644         return err;
645 }
646
647 int nilfs_near_disk_full(struct the_nilfs *nilfs)
648 {
649         struct inode *sufile = nilfs->ns_sufile;
650         unsigned long ncleansegs, nincsegs;
651         int ret;
652
653         ret = nilfs_sufile_get_ncleansegs(sufile, &ncleansegs);
654         if (likely(!ret)) {
655                 nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
656                         nilfs->ns_blocks_per_segment + 1;
657                 if (ncleansegs <= nilfs->ns_nrsvsegs + nincsegs)
658                         ret++;
659         }
660         return ret;
661 }
662
663 /**
664  * nilfs_find_sbinfo - find existing nilfs_sb_info structure
665  * @nilfs: nilfs object
666  * @rw_mount: mount type (non-zero value for read/write mount)
667  * @cno: checkpoint number (zero for read-only mount)
668  *
669  * nilfs_find_sbinfo() returns the nilfs_sb_info structure which
670  * @rw_mount and @cno (in case of snapshots) matched.  If no instance
671  * was found, NULL is returned.  Although the super block instance can
672  * be unmounted after this function returns, the nilfs_sb_info struct
673  * is kept on memory until nilfs_put_sbinfo() is called.
674  */
675 struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *nilfs,
676                                         int rw_mount, __u64 cno)
677 {
678         struct nilfs_sb_info *sbi;
679
680         down_read(&nilfs->ns_super_sem);
681         /*
682          * The SNAPSHOT flag and sb->s_flags are supposed to be
683          * protected with nilfs->ns_super_sem.
684          */
685         sbi = nilfs->ns_current;
686         if (rw_mount) {
687                 if (sbi && !(sbi->s_super->s_flags & MS_RDONLY))
688                         goto found; /* read/write mount */
689                 else
690                         goto out;
691         } else if (cno == 0) {
692                 if (sbi && (sbi->s_super->s_flags & MS_RDONLY))
693                         goto found; /* read-only mount */
694                 else
695                         goto out;
696         }
697
698         list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
699                 if (nilfs_test_opt(sbi, SNAPSHOT) &&
700                     sbi->s_snapshot_cno == cno)
701                         goto found; /* snapshot mount */
702         }
703  out:
704         up_read(&nilfs->ns_super_sem);
705         return NULL;
706
707  found:
708         atomic_inc(&sbi->s_count);
709         up_read(&nilfs->ns_super_sem);
710         return sbi;
711 }
712
713 int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno,
714                                 int snapshot_mount)
715 {
716         struct nilfs_sb_info *sbi;
717         int ret = 0;
718
719         down_read(&nilfs->ns_super_sem);
720         if (cno == 0 || cno > nilfs->ns_cno)
721                 goto out_unlock;
722
723         list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
724                 if (sbi->s_snapshot_cno == cno &&
725                     (!snapshot_mount || nilfs_test_opt(sbi, SNAPSHOT))) {
726                                         /* exclude read-only mounts */
727                         ret++;
728                         break;
729                 }
730         }
731         /* for protecting recent checkpoints */
732         if (cno >= nilfs_last_cno(nilfs))
733                 ret++;
734
735  out_unlock:
736         up_read(&nilfs->ns_super_sem);
737         return ret;
738 }