nilfs2: remove timedwait ioctl command
[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 "nilfs.h"
29 #include "segment.h"
30 #include "alloc.h"
31 #include "cpfile.h"
32 #include "sufile.h"
33 #include "dat.h"
34 #include "seglist.h"
35 #include "segbuf.h"
36
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         spin_unlock(&nilfs->ns_last_segment_lock);
45 }
46
47 /**
48  * alloc_nilfs - allocate the_nilfs structure
49  * @bdev: block device to which the_nilfs is related
50  *
51  * alloc_nilfs() allocates memory for the_nilfs and
52  * initializes its reference count and locks.
53  *
54  * Return Value: On success, pointer to the_nilfs is returned.
55  * On error, NULL is returned.
56  */
57 struct the_nilfs *alloc_nilfs(struct block_device *bdev)
58 {
59         struct the_nilfs *nilfs;
60
61         nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
62         if (!nilfs)
63                 return NULL;
64
65         nilfs->ns_bdev = bdev;
66         atomic_set(&nilfs->ns_count, 1);
67         atomic_set(&nilfs->ns_writer_refcount, -1);
68         atomic_set(&nilfs->ns_ndirtyblks, 0);
69         init_rwsem(&nilfs->ns_sem);
70         mutex_init(&nilfs->ns_writer_mutex);
71         INIT_LIST_HEAD(&nilfs->ns_supers);
72         spin_lock_init(&nilfs->ns_last_segment_lock);
73         nilfs->ns_gc_inodes_h = NULL;
74         INIT_LIST_HEAD(&nilfs->ns_used_segments);
75         init_rwsem(&nilfs->ns_segctor_sem);
76
77         return nilfs;
78 }
79
80 /**
81  * put_nilfs - release a reference to the_nilfs
82  * @nilfs: the_nilfs structure to be released
83  *
84  * put_nilfs() decrements a reference counter of the_nilfs.
85  * If the reference count reaches zero, the_nilfs is freed.
86  */
87 void put_nilfs(struct the_nilfs *nilfs)
88 {
89         if (!atomic_dec_and_test(&nilfs->ns_count))
90                 return;
91         /*
92          * Increment of ns_count never occur below because the caller
93          * of get_nilfs() holds at least one reference to the_nilfs.
94          * Thus its exclusion control is not required here.
95          */
96         might_sleep();
97         if (nilfs_loaded(nilfs)) {
98                 nilfs_dispose_used_segments(nilfs);
99                 nilfs_mdt_clear(nilfs->ns_sufile);
100                 nilfs_mdt_destroy(nilfs->ns_sufile);
101                 nilfs_mdt_clear(nilfs->ns_cpfile);
102                 nilfs_mdt_destroy(nilfs->ns_cpfile);
103                 nilfs_mdt_clear(nilfs->ns_dat);
104                 nilfs_mdt_destroy(nilfs->ns_dat);
105                 /* XXX: how and when to clear nilfs->ns_gc_dat? */
106                 nilfs_mdt_destroy(nilfs->ns_gc_dat);
107         }
108         if (nilfs_init(nilfs)) {
109                 nilfs_destroy_gccache(nilfs);
110                 brelse(nilfs->ns_sbh);
111         }
112         kfree(nilfs);
113 }
114
115 static int nilfs_load_super_root(struct the_nilfs *nilfs,
116                                  struct nilfs_sb_info *sbi, sector_t sr_block)
117 {
118         struct buffer_head *bh_sr;
119         struct nilfs_super_root *raw_sr;
120         unsigned dat_entry_size, segment_usage_size, checkpoint_size;
121         unsigned inode_size;
122         int err;
123
124         err = nilfs_read_super_root_block(sbi->s_super, sr_block, &bh_sr, 1);
125         if (unlikely(err))
126                 return err;
127
128         down_read(&nilfs->ns_sem);
129         dat_entry_size = le16_to_cpu(nilfs->ns_sbp->s_dat_entry_size);
130         checkpoint_size = le16_to_cpu(nilfs->ns_sbp->s_checkpoint_size);
131         segment_usage_size = le16_to_cpu(nilfs->ns_sbp->s_segment_usage_size);
132         up_read(&nilfs->ns_sem);
133
134         inode_size = nilfs->ns_inode_size;
135
136         err = -ENOMEM;
137         nilfs->ns_dat = nilfs_mdt_new(
138                 nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
139         if (unlikely(!nilfs->ns_dat))
140                 goto failed;
141
142         nilfs->ns_gc_dat = nilfs_mdt_new(
143                 nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
144         if (unlikely(!nilfs->ns_gc_dat))
145                 goto failed_dat;
146
147         nilfs->ns_cpfile = nilfs_mdt_new(
148                 nilfs, NULL, NILFS_CPFILE_INO, NILFS_CPFILE_GFP);
149         if (unlikely(!nilfs->ns_cpfile))
150                 goto failed_gc_dat;
151
152         nilfs->ns_sufile = nilfs_mdt_new(
153                 nilfs, NULL, NILFS_SUFILE_INO, NILFS_SUFILE_GFP);
154         if (unlikely(!nilfs->ns_sufile))
155                 goto failed_cpfile;
156
157         err = nilfs_palloc_init_blockgroup(nilfs->ns_dat, dat_entry_size);
158         if (unlikely(err))
159                 goto failed_sufile;
160
161         err = nilfs_palloc_init_blockgroup(nilfs->ns_gc_dat, dat_entry_size);
162         if (unlikely(err))
163                 goto failed_sufile;
164
165         nilfs_mdt_set_shadow(nilfs->ns_dat, nilfs->ns_gc_dat);
166         nilfs_mdt_set_entry_size(nilfs->ns_cpfile, checkpoint_size,
167                                  sizeof(struct nilfs_cpfile_header));
168         nilfs_mdt_set_entry_size(nilfs->ns_sufile, segment_usage_size,
169                                  sizeof(struct nilfs_sufile_header));
170
171         err = nilfs_mdt_read_inode_direct(
172                 nilfs->ns_dat, bh_sr, NILFS_SR_DAT_OFFSET(inode_size));
173         if (unlikely(err))
174                 goto failed_sufile;
175
176         err = nilfs_mdt_read_inode_direct(
177                 nilfs->ns_cpfile, bh_sr, NILFS_SR_CPFILE_OFFSET(inode_size));
178         if (unlikely(err))
179                 goto failed_sufile;
180
181         err = nilfs_mdt_read_inode_direct(
182                 nilfs->ns_sufile, bh_sr, NILFS_SR_SUFILE_OFFSET(inode_size));
183         if (unlikely(err))
184                 goto failed_sufile;
185
186         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
187         nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
188
189  failed:
190         brelse(bh_sr);
191         return err;
192
193  failed_sufile:
194         nilfs_mdt_destroy(nilfs->ns_sufile);
195
196  failed_cpfile:
197         nilfs_mdt_destroy(nilfs->ns_cpfile);
198
199  failed_gc_dat:
200         nilfs_mdt_destroy(nilfs->ns_gc_dat);
201
202  failed_dat:
203         nilfs_mdt_destroy(nilfs->ns_dat);
204         goto failed;
205 }
206
207 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
208 {
209         memset(ri, 0, sizeof(*ri));
210         INIT_LIST_HEAD(&ri->ri_used_segments);
211 }
212
213 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
214 {
215         nilfs_dispose_segment_list(&ri->ri_used_segments);
216 }
217
218 /**
219  * load_nilfs - load and recover the nilfs
220  * @nilfs: the_nilfs structure to be released
221  * @sbi: nilfs_sb_info used to recover past segment
222  *
223  * load_nilfs() searches and load the latest super root,
224  * attaches the last segment, and does recovery if needed.
225  * The caller must call this exclusively for simultaneous mounts.
226  */
227 int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
228 {
229         struct nilfs_recovery_info ri;
230         unsigned int s_flags = sbi->s_super->s_flags;
231         int really_read_only = bdev_read_only(nilfs->ns_bdev);
232         unsigned valid_fs;
233         int err = 0;
234
235         nilfs_init_recovery_info(&ri);
236
237         down_write(&nilfs->ns_sem);
238         valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
239         up_write(&nilfs->ns_sem);
240
241         if (!valid_fs && (s_flags & MS_RDONLY)) {
242                 printk(KERN_INFO "NILFS: INFO: recovery "
243                        "required for readonly filesystem.\n");
244                 if (really_read_only) {
245                         printk(KERN_ERR "NILFS: write access "
246                                "unavailable, cannot proceed.\n");
247                         err = -EROFS;
248                         goto failed;
249                 }
250                 printk(KERN_INFO "NILFS: write access will "
251                        "be enabled during recovery.\n");
252                 sbi->s_super->s_flags &= ~MS_RDONLY;
253         }
254
255         err = nilfs_search_super_root(nilfs, sbi, &ri);
256         if (unlikely(err)) {
257                 printk(KERN_ERR "NILFS: error searching super root.\n");
258                 goto failed;
259         }
260
261         err = nilfs_load_super_root(nilfs, sbi, ri.ri_super_root);
262         if (unlikely(err)) {
263                 printk(KERN_ERR "NILFS: error loading super root.\n");
264                 goto failed;
265         }
266
267         if (!valid_fs) {
268                 err = nilfs_recover_logical_segments(nilfs, sbi, &ri);
269                 if (unlikely(err)) {
270                         nilfs_mdt_destroy(nilfs->ns_cpfile);
271                         nilfs_mdt_destroy(nilfs->ns_sufile);
272                         nilfs_mdt_destroy(nilfs->ns_dat);
273                         goto failed;
274                 }
275                 if (ri.ri_need_recovery == NILFS_RECOVERY_SR_UPDATED) {
276                         down_write(&nilfs->ns_sem);
277                         nilfs_update_last_segment(sbi, 0);
278                         up_write(&nilfs->ns_sem);
279                 }
280         }
281
282         set_nilfs_loaded(nilfs);
283
284  failed:
285         nilfs_clear_recovery_info(&ri);
286         sbi->s_super->s_flags = s_flags;
287         return err;
288 }
289
290 static unsigned long long nilfs_max_size(unsigned int blkbits)
291 {
292         unsigned int max_bits;
293         unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
294
295         max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
296         if (max_bits < 64)
297                 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
298         return res;
299 }
300
301 static int
302 nilfs_store_disk_layout(struct the_nilfs *nilfs, struct super_block *sb,
303                         struct nilfs_super_block *sbp)
304 {
305         if (le32_to_cpu(sbp->s_rev_level) != NILFS_CURRENT_REV) {
306                 printk(KERN_ERR "NILFS: revision mismatch "
307                        "(superblock rev.=%d.%d, current rev.=%d.%d). "
308                        "Please check the version of mkfs.nilfs.\n",
309                        le32_to_cpu(sbp->s_rev_level),
310                        le16_to_cpu(sbp->s_minor_rev_level),
311                        NILFS_CURRENT_REV, NILFS_MINOR_REV);
312                 return -EINVAL;
313         }
314         nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
315         nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
316
317         nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
318         if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
319                 printk(KERN_ERR "NILFS: too short segment. \n");
320                 return -EINVAL;
321         }
322
323         nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
324         nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
325         nilfs->ns_r_segments_percentage =
326                 le32_to_cpu(sbp->s_r_segments_percentage);
327         nilfs->ns_nrsvsegs =
328                 max_t(unsigned long, NILFS_MIN_NRSVSEGS,
329                       DIV_ROUND_UP(nilfs->ns_nsegments *
330                                    nilfs->ns_r_segments_percentage, 100));
331         nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
332         return 0;
333 }
334
335 /**
336  * init_nilfs - initialize a NILFS instance.
337  * @nilfs: the_nilfs structure
338  * @sbi: nilfs_sb_info
339  * @sb: super block
340  * @data: mount options
341  *
342  * init_nilfs() performs common initialization per block device (e.g.
343  * reading the super block, getting disk layout information, initializing
344  * shared fields in the_nilfs). It takes on some portion of the jobs
345  * typically done by a fill_super() routine. This division arises from
346  * the nature that multiple NILFS instances may be simultaneously
347  * mounted on a device.
348  * For multiple mounts on the same device, only the first mount
349  * invokes these tasks.
350  *
351  * Return Value: On success, 0 is returned. On error, a negative error
352  * code is returned.
353  */
354 int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
355 {
356         struct super_block *sb = sbi->s_super;
357         struct buffer_head *sbh;
358         struct nilfs_super_block *sbp;
359         struct backing_dev_info *bdi;
360         int blocksize;
361         int err = 0;
362
363         down_write(&nilfs->ns_sem);
364         if (nilfs_init(nilfs)) {
365                 /* Load values from existing the_nilfs */
366                 sbp = nilfs->ns_sbp;
367                 err = nilfs_store_magic_and_option(sb, sbp, data);
368                 if (err)
369                         goto out;
370
371                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
372                 if (sb->s_blocksize != blocksize &&
373                     !sb_set_blocksize(sb, blocksize)) {
374                         printk(KERN_ERR "NILFS: blocksize %d unfit to device\n",
375                                blocksize);
376                         err = -EINVAL;
377                 }
378                 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
379                 goto out;
380         }
381
382         sbp = nilfs_load_super_block(sb, &sbh);
383         if (!sbp) {
384                 err = -EINVAL;
385                 goto out;
386         }
387         err = nilfs_store_magic_and_option(sb, sbp, data);
388         if (err)
389                 goto failed_sbh;
390
391         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
392         if (sb->s_blocksize != blocksize) {
393                 sbp = nilfs_reload_super_block(sb, &sbh, blocksize);
394                 if (!sbp) {
395                         err = -EINVAL;
396                         goto out;
397                         /* not failed_sbh; sbh is released automatically
398                            when reloading fails. */
399                 }
400         }
401         nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
402
403         err = nilfs_store_disk_layout(nilfs, sb, sbp);
404         if (err)
405                 goto failed_sbh;
406
407         sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
408
409         nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
410         nilfs->ns_sbh = sbh;
411         nilfs->ns_sbp = sbp;
412
413         bdi = nilfs->ns_bdev->bd_inode_backing_dev_info;
414         if (!bdi)
415                 bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info;
416         nilfs->ns_bdi = bdi ? : &default_backing_dev_info;
417
418         /* Finding last segment */
419         nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
420         nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
421         nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
422
423         nilfs->ns_seg_seq = nilfs->ns_last_seq;
424         nilfs->ns_segnum =
425                 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
426         nilfs->ns_cno = nilfs->ns_last_cno + 1;
427         if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
428                 printk(KERN_ERR "NILFS invalid last segment number.\n");
429                 err = -EINVAL;
430                 goto failed_sbh;
431         }
432         /* Dummy values  */
433         nilfs->ns_free_segments_count =
434                 nilfs->ns_nsegments - (nilfs->ns_segnum + 1);
435
436         /* Initialize gcinode cache */
437         err = nilfs_init_gccache(nilfs);
438         if (err)
439                 goto failed_sbh;
440
441         set_nilfs_init(nilfs);
442         err = 0;
443  out:
444         up_write(&nilfs->ns_sem);
445         return err;
446
447  failed_sbh:
448         brelse(sbh);
449         goto out;
450 }
451
452 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
453 {
454         struct inode *dat = nilfs_dat_inode(nilfs);
455         unsigned long ncleansegs;
456         int err;
457
458         down_read(&NILFS_MDT(dat)->mi_sem);     /* XXX */
459         err = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile, &ncleansegs);
460         up_read(&NILFS_MDT(dat)->mi_sem);       /* XXX */
461         if (likely(!err))
462                 *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
463         return err;
464 }
465
466 void nilfs_dispose_used_segments(struct the_nilfs *nilfs)
467 {
468         struct nilfs_segment_entry *ent, *n;
469
470         /* nilfs->sem must be locked by the caller. */
471         if (!nilfs_loaded(nilfs))
472                 return;
473
474         list_for_each_entry_safe(ent, n, &nilfs->ns_used_segments, list) {
475                 list_del_init(&ent->list);
476                 nilfs_segment_usage_clear_volatile_active(ent->raw_su);
477                 nilfs_close_segment_entry(ent, nilfs->ns_sufile);
478                 nilfs_free_segment_entry(ent);
479         }
480 }
481
482 int nilfs_near_disk_full(struct the_nilfs *nilfs)
483 {
484         struct inode *sufile = nilfs->ns_sufile;
485         unsigned long ncleansegs, nincsegs;
486         int ret;
487
488         ret = nilfs_sufile_get_ncleansegs(sufile, &ncleansegs);
489         if (likely(!ret)) {
490                 nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
491                         nilfs->ns_blocks_per_segment + 1;
492                 if (ncleansegs <= nilfs->ns_nrsvsegs + nincsegs)
493                         ret++;
494         }
495         return ret;
496 }
497
498 int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno,
499                                 int snapshot_mount)
500 {
501         struct nilfs_sb_info *sbi;
502         int ret = 0;
503
504         down_read(&nilfs->ns_sem);
505         if (cno == 0 || cno > nilfs->ns_cno)
506                 goto out_unlock;
507
508         list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
509                 if (sbi->s_snapshot_cno == cno &&
510                     (!snapshot_mount || nilfs_test_opt(sbi, SNAPSHOT))) {
511                                         /* exclude read-only mounts */
512                         ret++;
513                         break;
514                 }
515         }
516         /* for protecting recent checkpoints */
517         if (cno >= nilfs_last_cno(nilfs))
518                 ret++;
519
520  out_unlock:
521         up_read(&nilfs->ns_sem);
522         return ret;
523 }