Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/fs/logfs/super.c

  1 /*
  2  * fs/logfs/super.c
  3  *
  4  * As should be obvious for Linux kernel code, license is GPLv2
  5  *
  6  * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
  7  *
  8  * Generally contains mount/umount code and also serves as a dump area for
  9  * any functions that don't fit elsewhere and neither justify a file of their
 10  * own.
 11  */
 12 #include "logfs.h"
 13 #include <linux/bio.h>
 14 #include <linux/slab.h>
 15 #include <linux/blkdev.h>
 16 #include <linux/module.h>
 17 #include <linux/mtd/mtd.h>
 18 #include <linux/statfs.h>
 19 #include <linux/buffer_head.h>
 20 
 21 static DEFINE_MUTEX(emergency_mutex);
 22 static struct page *emergency_page;
 23 
 24 struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index)
 25 {
 26         filler_t *filler = (filler_t *)mapping->a_ops->readpage;
 27         struct page *page;
 28         int err;
 29 
 30         page = read_cache_page(mapping, index, filler, NULL);
 31         if (page)
 32                 return page;
 33 
 34         /* No more pages available, switch to emergency page */
 35         printk(KERN_INFO"Logfs: Using emergency page\n");
 36         mutex_lock(&emergency_mutex);
 37         err = filler(NULL, emergency_page);
 38         if (err) {
 39                 mutex_unlock(&emergency_mutex);
 40                 printk(KERN_EMERG"Logfs: Error reading emergency page\n");
 41                 return ERR_PTR(err);
 42         }
 43         return emergency_page;
 44 }
 45 
 46 void emergency_read_end(struct page *page)
 47 {
 48         if (page == emergency_page)
 49                 mutex_unlock(&emergency_mutex);
 50         else
 51                 page_cache_release(page);
 52 }
 53 
 54 static void dump_segfile(struct super_block *sb)
 55 {
 56         struct logfs_super *super = logfs_super(sb);
 57         struct logfs_segment_entry se;
 58         u32 segno;
 59 
 60         for (segno = 0; segno < super->s_no_segs; segno++) {
 61                 logfs_get_segment_entry(sb, segno, &se);
 62                 printk("%3x: %6x %8x", segno, be32_to_cpu(se.ec_level),
 63                                 be32_to_cpu(se.valid));
 64                 if (++segno < super->s_no_segs) {
 65                         logfs_get_segment_entry(sb, segno, &se);
 66                         printk(" %6x %8x", be32_to_cpu(se.ec_level),
 67                                         be32_to_cpu(se.valid));
 68                 }
 69                 if (++segno < super->s_no_segs) {
 70                         logfs_get_segment_entry(sb, segno, &se);
 71                         printk(" %6x %8x", be32_to_cpu(se.ec_level),
 72                                         be32_to_cpu(se.valid));
 73                 }
 74                 if (++segno < super->s_no_segs) {
 75                         logfs_get_segment_entry(sb, segno, &se);
 76                         printk(" %6x %8x", be32_to_cpu(se.ec_level),
 77                                         be32_to_cpu(se.valid));
 78                 }
 79                 printk("\n");
 80         }
 81 }
 82 
 83 /*
 84  * logfs_crash_dump - dump debug information to device
 85  *
 86  * The LogFS superblock only occupies part of a segment.  This function will
 87  * write as much debug information as it can gather into the spare space.
 88  */
 89 void logfs_crash_dump(struct super_block *sb)
 90 {
 91         dump_segfile(sb);
 92 }
 93 
 94 /*
 95  * FIXME: There should be a reserve for root, similar to ext2.
 96  */
 97 int logfs_statfs(struct dentry *dentry, struct kstatfs *stats)
 98 {
 99         struct super_block *sb = dentry->d_sb;
100         struct logfs_super *super = logfs_super(sb);
101 
102         stats->f_type           = LOGFS_MAGIC_U32;
103         stats->f_bsize          = sb->s_blocksize;
104         stats->f_blocks         = super->s_size >> LOGFS_BLOCK_BITS >> 3;
105         stats->f_bfree          = super->s_free_bytes >> sb->s_blocksize_bits;
106         stats->f_bavail         = super->s_free_bytes >> sb->s_blocksize_bits;
107         stats->f_files          = 0;
108         stats->f_ffree          = 0;
109         stats->f_namelen        = LOGFS_MAX_NAMELEN;
110         return 0;
111 }
112 
113 static int logfs_sb_set(struct super_block *sb, void *_super)
114 {
115         struct logfs_super *super = _super;
116 
117         sb->s_fs_info = super;
118         sb->s_mtd = super->s_mtd;
119         sb->s_bdev = super->s_bdev;
120 #ifdef CONFIG_BLOCK
121         if (sb->s_bdev)
122                 sb->s_bdi = &bdev_get_queue(sb->s_bdev)->backing_dev_info;
123 #endif
124 #ifdef CONFIG_MTD
125         if (sb->s_mtd)
126                 sb->s_bdi = sb->s_mtd->backing_dev_info;
127 #endif
128         return 0;
129 }
130 
131 static int logfs_sb_test(struct super_block *sb, void *_super)
132 {
133         struct logfs_super *super = _super;
134         struct mtd_info *mtd = super->s_mtd;
135 
136         if (mtd && sb->s_mtd == mtd)
137                 return 1;
138         if (super->s_bdev && sb->s_bdev == super->s_bdev)
139                 return 1;
140         return 0;
141 }
142 
143 static void set_segment_header(struct logfs_segment_header *sh, u8 type,
144                 u8 level, u32 segno, u32 ec)
145 {
146         sh->pad = 0;
147         sh->type = type;
148         sh->level = level;
149         sh->segno = cpu_to_be32(segno);
150         sh->ec = cpu_to_be32(ec);
151         sh->gec = cpu_to_be64(segno);
152         sh->crc = logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4);
153 }
154 
155 static void logfs_write_ds(struct super_block *sb, struct logfs_disk_super *ds,
156                 u32 segno, u32 ec)
157 {
158         struct logfs_super *super = logfs_super(sb);
159         struct logfs_segment_header *sh = &ds->ds_sh;
160         int i;
161 
162         memset(ds, 0, sizeof(*ds));
163         set_segment_header(sh, SEG_SUPER, 0, segno, ec);
164 
165         ds->ds_ifile_levels     = super->s_ifile_levels;
166         ds->ds_iblock_levels    = super->s_iblock_levels;
167         ds->ds_data_levels      = super->s_data_levels; /* XXX: Remove */
168         ds->ds_segment_shift    = super->s_segshift;
169         ds->ds_block_shift      = sb->s_blocksize_bits;
170         ds->ds_write_shift      = super->s_writeshift;
171         ds->ds_filesystem_size  = cpu_to_be64(super->s_size);
172         ds->ds_segment_size     = cpu_to_be32(super->s_segsize);
173         ds->ds_bad_seg_reserve  = cpu_to_be32(super->s_bad_seg_reserve);
174         ds->ds_feature_incompat = cpu_to_be64(super->s_feature_incompat);
175         ds->ds_feature_ro_compat= cpu_to_be64(super->s_feature_ro_compat);
176         ds->ds_feature_compat   = cpu_to_be64(super->s_feature_compat);
177         ds->ds_feature_flags    = cpu_to_be64(super->s_feature_flags);
178         ds->ds_root_reserve     = cpu_to_be64(super->s_root_reserve);
179         ds->ds_speed_reserve    = cpu_to_be64(super->s_speed_reserve);
180         journal_for_each(i)
181                 ds->ds_journal_seg[i] = cpu_to_be32(super->s_journal_seg[i]);
182         ds->ds_magic            = cpu_to_be64(LOGFS_MAGIC);
183         ds->ds_crc = logfs_crc32(ds, sizeof(*ds),
184                         LOGFS_SEGMENT_HEADERSIZE + 12);
185 }
186 
187 static int write_one_sb(struct super_block *sb,
188                 struct page *(*find_sb)(struct super_block *sb, u64 *ofs))
189 {
190         struct logfs_super *super = logfs_super(sb);
191         struct logfs_disk_super *ds;
192         struct logfs_segment_entry se;
193         struct page *page;
194         u64 ofs;
195         u32 ec, segno;
196         int err;
197 
198         page = find_sb(sb, &ofs);
199         if (!page)
200                 return -EIO;
201         ds = page_address(page);
202         segno = seg_no(sb, ofs);
203         logfs_get_segment_entry(sb, segno, &se);
204         ec = be32_to_cpu(se.ec_level) >> 4;
205         ec++;
206         logfs_set_segment_erased(sb, segno, ec, 0);
207         logfs_write_ds(sb, ds, segno, ec);
208         err = super->s_devops->write_sb(sb, page);
209         page_cache_release(page);
210         return err;
211 }
212 
213 int logfs_write_sb(struct super_block *sb)
214 {
215         struct logfs_super *super = logfs_super(sb);
216         int err;
217 
218         /* First superblock */
219         err = write_one_sb(sb, super->s_devops->find_first_sb);
220         if (err)
221                 return err;
222 
223         /* Last superblock */
224         err = write_one_sb(sb, super->s_devops->find_last_sb);
225         if (err)
226                 return err;
227         return 0;
228 }
229 
230 static int ds_cmp(const void *ds0, const void *ds1)
231 {
232         size_t len = sizeof(struct logfs_disk_super);
233 
234         /* We know the segment headers differ, so ignore them */
235         len -= LOGFS_SEGMENT_HEADERSIZE;
236         ds0 += LOGFS_SEGMENT_HEADERSIZE;
237         ds1 += LOGFS_SEGMENT_HEADERSIZE;
238         return memcmp(ds0, ds1, len);
239 }
240 
241 static int logfs_recover_sb(struct super_block *sb)
242 {
243         struct logfs_super *super = logfs_super(sb);
244         struct logfs_disk_super _ds0, *ds0 = &_ds0;
245         struct logfs_disk_super _ds1, *ds1 = &_ds1;
246         int err, valid0, valid1;
247 
248         /* read first superblock */
249         err = wbuf_read(sb, super->s_sb_ofs[0], sizeof(*ds0), ds0);
250         if (err)
251                 return err;
252         /* read last superblock */
253         err = wbuf_read(sb, super->s_sb_ofs[1], sizeof(*ds1), ds1);
254         if (err)
255                 return err;
256         valid0 = logfs_check_ds(ds0) == 0;
257         valid1 = logfs_check_ds(ds1) == 0;
258 
259         if (!valid0 && valid1) {
260                 printk(KERN_INFO"First superblock is invalid - fixing.\n");
261                 return write_one_sb(sb, super->s_devops->find_first_sb);
262         }
263         if (valid0 && !valid1) {
264                 printk(KERN_INFO"Last superblock is invalid - fixing.\n");
265                 return write_one_sb(sb, super->s_devops->find_last_sb);
266         }
267         if (valid0 && valid1 && ds_cmp(ds0, ds1)) {
268                 printk(KERN_INFO"Superblocks don't match - fixing.\n");
269                 return logfs_write_sb(sb);
270         }
271         /* If neither is valid now, something's wrong.  Didn't we properly
272          * check them before?!? */
273         BUG_ON(!valid0 && !valid1);
274         return 0;
275 }
276 
277 static int logfs_make_writeable(struct super_block *sb)
278 {
279         int err;
280 
281         err = logfs_open_segfile(sb);
282         if (err)
283                 return err;
284 
285         /* Repair any broken superblock copies */
286         err = logfs_recover_sb(sb);
287         if (err)
288                 return err;
289 
290         /* Check areas for trailing unaccounted data */
291         err = logfs_check_areas(sb);
292         if (err)
293                 return err;
294 
295         /* Do one GC pass before any data gets dirtied */
296         logfs_gc_pass(sb);
297 
298         /* after all initializations are done, replay the journal
299          * for rw-mounts, if necessary */
300         err = logfs_replay_journal(sb);
301         if (err)
302                 return err;
303 
304         return 0;
305 }
306 
307 static int logfs_get_sb_final(struct super_block *sb)
308 {
309         struct logfs_super *super = logfs_super(sb);
310         struct inode *rootdir;
311         int err;
312 
313         /* root dir */
314         rootdir = logfs_iget(sb, LOGFS_INO_ROOT);
315         if (IS_ERR(rootdir))
316                 goto fail;
317 
318         sb->s_root = d_make_root(rootdir);
319         if (!sb->s_root)
320                 goto fail;
321 
322         /* at that point we know that ->put_super() will be called */
323         super->s_erase_page = alloc_pages(GFP_KERNEL, 0);
324         if (!super->s_erase_page)
325                 return -ENOMEM;
326         memset(page_address(super->s_erase_page), 0xFF, PAGE_SIZE);
327 
328         /* FIXME: check for read-only mounts */
329         err = logfs_make_writeable(sb);
330         if (err) {
331                 __free_page(super->s_erase_page);
332                 return err;
333         }
334 
335         log_super("LogFS: Finished mounting\n");
336         return 0;
337 
338 fail:
339         iput(super->s_master_inode);
340         iput(super->s_segfile_inode);
341         iput(super->s_mapping_inode);
342         return -EIO;
343 }
344 
345 int logfs_check_ds(struct logfs_disk_super *ds)
346 {
347         struct logfs_segment_header *sh = &ds->ds_sh;
348 
349         if (ds->ds_magic != cpu_to_be64(LOGFS_MAGIC))
350                 return -EINVAL;
351         if (sh->crc != logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4))
352                 return -EINVAL;
353         if (ds->ds_crc != logfs_crc32(ds, sizeof(*ds),
354                                 LOGFS_SEGMENT_HEADERSIZE + 12))
355                 return -EINVAL;
356         return 0;
357 }
358 
359 static struct page *find_super_block(struct super_block *sb)
360 {
361         struct logfs_super *super = logfs_super(sb);
362         struct page *first, *last;
363 
364         first = super->s_devops->find_first_sb(sb, &super->s_sb_ofs[0]);
365         if (!first || IS_ERR(first))
366                 return NULL;
367         last = super->s_devops->find_last_sb(sb, &super->s_sb_ofs[1]);
368         if (!last || IS_ERR(last)) {
369                 page_cache_release(first);
370                 return NULL;
371         }
372 
373         if (!logfs_check_ds(page_address(first))) {
374                 page_cache_release(last);
375                 return first;
376         }
377 
378         /* First one didn't work, try the second superblock */
379         if (!logfs_check_ds(page_address(last))) {
380                 page_cache_release(first);
381                 return last;
382         }
383 
384         /* Neither worked, sorry folks */
385         page_cache_release(first);
386         page_cache_release(last);
387         return NULL;
388 }
389 
390 static int __logfs_read_sb(struct super_block *sb)
391 {
392         struct logfs_super *super = logfs_super(sb);
393         struct page *page;
394         struct logfs_disk_super *ds;
395         int i;
396 
397         page = find_super_block(sb);
398         if (!page)
399                 return -EINVAL;
400 
401         ds = page_address(page);
402         super->s_size = be64_to_cpu(ds->ds_filesystem_size);
403         super->s_root_reserve = be64_to_cpu(ds->ds_root_reserve);
404         super->s_speed_reserve = be64_to_cpu(ds->ds_speed_reserve);
405         super->s_bad_seg_reserve = be32_to_cpu(ds->ds_bad_seg_reserve);
406         super->s_segsize = 1 << ds->ds_segment_shift;
407         super->s_segmask = (1 << ds->ds_segment_shift) - 1;
408         super->s_segshift = ds->ds_segment_shift;
409         sb->s_blocksize = 1 << ds->ds_block_shift;
410         sb->s_blocksize_bits = ds->ds_block_shift;
411         super->s_writesize = 1 << ds->ds_write_shift;
412         super->s_writeshift = ds->ds_write_shift;
413         super->s_no_segs = super->s_size >> super->s_segshift;
414         super->s_no_blocks = super->s_segsize >> sb->s_blocksize_bits;
415         super->s_feature_incompat = be64_to_cpu(ds->ds_feature_incompat);
416         super->s_feature_ro_compat = be64_to_cpu(ds->ds_feature_ro_compat);
417         super->s_feature_compat = be64_to_cpu(ds->ds_feature_compat);
418         super->s_feature_flags = be64_to_cpu(ds->ds_feature_flags);
419 
420         journal_for_each(i)
421                 super->s_journal_seg[i] = be32_to_cpu(ds->ds_journal_seg[i]);
422 
423         super->s_ifile_levels = ds->ds_ifile_levels;
424         super->s_iblock_levels = ds->ds_iblock_levels;
425         super->s_data_levels = ds->ds_data_levels;
426         super->s_total_levels = super->s_ifile_levels + super->s_iblock_levels
427                 + super->s_data_levels;
428         page_cache_release(page);
429         return 0;
430 }
431 
432 static int logfs_read_sb(struct super_block *sb, int read_only)
433 {
434         struct logfs_super *super = logfs_super(sb);
435         int ret;
436 
437         super->s_btree_pool = mempool_create(32, btree_alloc, btree_free, NULL);
438         if (!super->s_btree_pool)
439                 return -ENOMEM;
440 
441         btree_init_mempool64(&super->s_shadow_tree.new, super->s_btree_pool);
442         btree_init_mempool64(&super->s_shadow_tree.old, super->s_btree_pool);
443         btree_init_mempool32(&super->s_shadow_tree.segment_map,
444                         super->s_btree_pool);
445 
446         ret = logfs_init_mapping(sb);
447         if (ret)
448                 return ret;
449 
450         ret = __logfs_read_sb(sb);
451         if (ret)
452                 return ret;
453 
454         if (super->s_feature_incompat & ~LOGFS_FEATURES_INCOMPAT)
455                 return -EIO;
456         if ((super->s_feature_ro_compat & ~LOGFS_FEATURES_RO_COMPAT) &&
457                         !read_only)
458                 return -EIO;
459 
460         ret = logfs_init_rw(sb);
461         if (ret)
462                 return ret;
463 
464         ret = logfs_init_areas(sb);
465         if (ret)
466                 return ret;
467 
468         ret = logfs_init_gc(sb);
469         if (ret)
470                 return ret;
471 
472         ret = logfs_init_journal(sb);
473         if (ret)
474                 return ret;
475 
476         return 0;
477 }
478 
479 static void logfs_kill_sb(struct super_block *sb)
480 {
481         struct logfs_super *super = logfs_super(sb);
482 
483         log_super("LogFS: Start unmounting\n");
484         /* Alias entries slow down mount, so evict as many as possible */
485         sync_filesystem(sb);
486         logfs_write_anchor(sb);
487         free_areas(sb);
488 
489         /*
490          * From this point on alias entries are simply dropped - and any
491          * writes to the object store are considered bugs.
492          */
493         log_super("LogFS: Now in shutdown\n");
494         generic_shutdown_super(sb);
495         super->s_flags |= LOGFS_SB_FLAG_SHUTDOWN;
496 
497         BUG_ON(super->s_dirty_used_bytes || super->s_dirty_free_bytes);
498 
499         logfs_cleanup_gc(sb);
500         logfs_cleanup_journal(sb);
501         logfs_cleanup_areas(sb);
502         logfs_cleanup_rw(sb);
503         if (super->s_erase_page)
504                 __free_page(super->s_erase_page);
505         super->s_devops->put_device(super);
506         logfs_mempool_destroy(super->s_btree_pool);
507         logfs_mempool_destroy(super->s_alias_pool);
508         kfree(super);
509         log_super("LogFS: Finished unmounting\n");
510 }
511 
512 static struct dentry *logfs_get_sb_device(struct logfs_super *super,
513                 struct file_system_type *type, int flags)
514 {
515         struct super_block *sb;
516         int err = -ENOMEM;
517         static int mount_count;
518 
519         log_super("LogFS: Start mount %x\n", mount_count++);
520 
521         err = -EINVAL;
522         sb = sget(type, logfs_sb_test, logfs_sb_set, flags | MS_NOATIME, super);
523         if (IS_ERR(sb)) {
524                 super->s_devops->put_device(super);
525                 kfree(super);
526                 return ERR_CAST(sb);
527         }
528 
529         if (sb->s_root) {
530                 /* Device is already in use */
531                 super->s_devops->put_device(super);
532                 kfree(super);
533                 return dget(sb->s_root);
534         }
535 
536         /*
537          * sb->s_maxbytes is limited to 8TB.  On 32bit systems, the page cache
538          * only covers 16TB and the upper 8TB are used for indirect blocks.
539          * On 64bit system we could bump up the limit, but that would make
540          * the filesystem incompatible with 32bit systems.
541          */
542         sb->s_maxbytes  = (1ull << 43) - 1;
543         sb->s_max_links = LOGFS_LINK_MAX;
544         sb->s_op        = &logfs_super_operations;
545 
546         err = logfs_read_sb(sb, sb->s_flags & MS_RDONLY);
547         if (err)
548                 goto err1;
549 
550         sb->s_flags |= MS_ACTIVE;
551         err = logfs_get_sb_final(sb);
552         if (err) {
553                 deactivate_locked_super(sb);
554                 return ERR_PTR(err);
555         }
556         return dget(sb->s_root);
557 
558 err1:
559         /* no ->s_root, no ->put_super() */
560         iput(super->s_master_inode);
561         iput(super->s_segfile_inode);
562         iput(super->s_mapping_inode);
563         deactivate_locked_super(sb);
564         return ERR_PTR(err);
565 }
566 
567 static struct dentry *logfs_mount(struct file_system_type *type, int flags,
568                 const char *devname, void *data)
569 {
570         ulong mtdnr;
571         struct logfs_super *super;
572         int err;
573 
574         super = kzalloc(sizeof(*super), GFP_KERNEL);
575         if (!super)
576                 return ERR_PTR(-ENOMEM);
577 
578         mutex_init(&super->s_dirop_mutex);
579         mutex_init(&super->s_object_alias_mutex);
580         INIT_LIST_HEAD(&super->s_freeing_list);
581 
582         if (!devname)
583                 err = logfs_get_sb_bdev(super, type, devname);
584         else if (strncmp(devname, "mtd", 3))
585                 err = logfs_get_sb_bdev(super, type, devname);
586         else {
587                 char *garbage;
588                 mtdnr = simple_strtoul(devname+3, &garbage, 0);
589                 if (*garbage)
590                         err = -EINVAL;
591                 else
592                         err = logfs_get_sb_mtd(super, mtdnr);
593         }
594 
595         if (err) {
596                 kfree(super);
597                 return ERR_PTR(err);
598         }
599 
600         return logfs_get_sb_device(super, type, flags);
601 }
602 
603 static struct file_system_type logfs_fs_type = {
604         .owner          = THIS_MODULE,
605         .name           = "logfs",
606         .mount          = logfs_mount,
607         .kill_sb        = logfs_kill_sb,
608         .fs_flags       = FS_REQUIRES_DEV,
609 
610 };
611 MODULE_ALIAS_FS("logfs");
612 
613 static int __init logfs_init(void)
614 {
615         int ret;
616 
617         emergency_page = alloc_pages(GFP_KERNEL, 0);
618         if (!emergency_page)
619                 return -ENOMEM;
620 
621         ret = logfs_compr_init();
622         if (ret)
623                 goto out1;
624 
625         ret = logfs_init_inode_cache();
626         if (ret)
627                 goto out2;
628 
629         ret = register_filesystem(&logfs_fs_type);
630         if (!ret)
631                 return 0;
632         logfs_destroy_inode_cache();
633 out2:
634         logfs_compr_exit();
635 out1:
636         __free_pages(emergency_page, 0);
637         return ret;
638 }
639 
640 static void __exit logfs_exit(void)
641 {
642         unregister_filesystem(&logfs_fs_type);
643         logfs_destroy_inode_cache();
644         logfs_compr_exit();
645         __free_pages(emergency_page, 0);
646 }
647 
648 module_init(logfs_init);
649 module_exit(logfs_exit);
650 
651 MODULE_LICENSE("GPL v2");
652 MODULE_AUTHOR("Joern Engel <joern@logfs.org>");
653 MODULE_DESCRIPTION("scalable flash filesystem");
654 

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