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-rw-r--r--fs/logfs/super.c650
1 files changed, 650 insertions, 0 deletions
diff --git a/fs/logfs/super.c b/fs/logfs/super.c
new file mode 100644
index 000000000000..c66beab78dee
--- /dev/null
+++ b/fs/logfs/super.c
@@ -0,0 +1,650 @@
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/mtd/mtd.h>
15#include <linux/statfs.h>
16#include <linux/buffer_head.h>
17
18static DEFINE_MUTEX(emergency_mutex);
19static struct page *emergency_page;
20
21struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index)
22{
23 filler_t *filler = (filler_t *)mapping->a_ops->readpage;
24 struct page *page;
25 int err;
26
27 page = read_cache_page(mapping, index, filler, NULL);
28 if (page)
29 return page;
30
31 /* No more pages available, switch to emergency page */
32 printk(KERN_INFO"Logfs: Using emergency page\n");
33 mutex_lock(&emergency_mutex);
34 err = filler(NULL, emergency_page);
35 if (err) {
36 mutex_unlock(&emergency_mutex);
37 printk(KERN_EMERG"Logfs: Error reading emergency page\n");
38 return ERR_PTR(err);
39 }
40 return emergency_page;
41}
42
43void emergency_read_end(struct page *page)
44{
45 if (page == emergency_page)
46 mutex_unlock(&emergency_mutex);
47 else
48 page_cache_release(page);
49}
50
51static void dump_segfile(struct super_block *sb)
52{
53 struct logfs_super *super = logfs_super(sb);
54 struct logfs_segment_entry se;
55 u32 segno;
56
57 for (segno = 0; segno < super->s_no_segs; segno++) {
58 logfs_get_segment_entry(sb, segno, &se);
59 printk("%3x: %6x %8x", segno, be32_to_cpu(se.ec_level),
60 be32_to_cpu(se.valid));
61 if (++segno < super->s_no_segs) {
62 logfs_get_segment_entry(sb, segno, &se);
63 printk(" %6x %8x", be32_to_cpu(se.ec_level),
64 be32_to_cpu(se.valid));
65 }
66 if (++segno < super->s_no_segs) {
67 logfs_get_segment_entry(sb, segno, &se);
68 printk(" %6x %8x", be32_to_cpu(se.ec_level),
69 be32_to_cpu(se.valid));
70 }
71 if (++segno < super->s_no_segs) {
72 logfs_get_segment_entry(sb, segno, &se);
73 printk(" %6x %8x", be32_to_cpu(se.ec_level),
74 be32_to_cpu(se.valid));
75 }
76 printk("\n");
77 }
78}
79
80/*
81 * logfs_crash_dump - dump debug information to device
82 *
83 * The LogFS superblock only occupies part of a segment. This function will
84 * write as much debug information as it can gather into the spare space.
85 */
86void logfs_crash_dump(struct super_block *sb)
87{
88 dump_segfile(sb);
89}
90
91/*
92 * TODO: move to lib/string.c
93 */
94/**
95 * memchr_inv - Find a character in an area of memory.
96 * @s: The memory area
97 * @c: The byte to search for
98 * @n: The size of the area.
99 *
100 * returns the address of the first character other than @c, or %NULL
101 * if the whole buffer contains just @c.
102 */
103void *memchr_inv(const void *s, int c, size_t n)
104{
105 const unsigned char *p = s;
106 while (n-- != 0)
107 if ((unsigned char)c != *p++)
108 return (void *)(p - 1);
109
110 return NULL;
111}
112
113/*
114 * FIXME: There should be a reserve for root, similar to ext2.
115 */
116int logfs_statfs(struct dentry *dentry, struct kstatfs *stats)
117{
118 struct super_block *sb = dentry->d_sb;
119 struct logfs_super *super = logfs_super(sb);
120
121 stats->f_type = LOGFS_MAGIC_U32;
122 stats->f_bsize = sb->s_blocksize;
123 stats->f_blocks = super->s_size >> LOGFS_BLOCK_BITS >> 3;
124 stats->f_bfree = super->s_free_bytes >> sb->s_blocksize_bits;
125 stats->f_bavail = super->s_free_bytes >> sb->s_blocksize_bits;
126 stats->f_files = 0;
127 stats->f_ffree = 0;
128 stats->f_namelen = LOGFS_MAX_NAMELEN;
129 return 0;
130}
131
132static int logfs_sb_set(struct super_block *sb, void *_super)
133{
134 struct logfs_super *super = _super;
135
136 sb->s_fs_info = super;
137 sb->s_mtd = super->s_mtd;
138 sb->s_bdev = super->s_bdev;
139 return 0;
140}
141
142static int logfs_sb_test(struct super_block *sb, void *_super)
143{
144 struct logfs_super *super = _super;
145 struct mtd_info *mtd = super->s_mtd;
146
147 if (mtd && sb->s_mtd == mtd)
148 return 1;
149 if (super->s_bdev && sb->s_bdev == super->s_bdev)
150 return 1;
151 return 0;
152}
153
154static void set_segment_header(struct logfs_segment_header *sh, u8 type,
155 u8 level, u32 segno, u32 ec)
156{
157 sh->pad = 0;
158 sh->type = type;
159 sh->level = level;
160 sh->segno = cpu_to_be32(segno);
161 sh->ec = cpu_to_be32(ec);
162 sh->gec = cpu_to_be64(segno);
163 sh->crc = logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4);
164}
165
166static void logfs_write_ds(struct super_block *sb, struct logfs_disk_super *ds,
167 u32 segno, u32 ec)
168{
169 struct logfs_super *super = logfs_super(sb);
170 struct logfs_segment_header *sh = &ds->ds_sh;
171 int i;
172
173 memset(ds, 0, sizeof(*ds));
174 set_segment_header(sh, SEG_SUPER, 0, segno, ec);
175
176 ds->ds_ifile_levels = super->s_ifile_levels;
177 ds->ds_iblock_levels = super->s_iblock_levels;
178 ds->ds_data_levels = super->s_data_levels; /* XXX: Remove */
179 ds->ds_segment_shift = super->s_segshift;
180 ds->ds_block_shift = sb->s_blocksize_bits;
181 ds->ds_write_shift = super->s_writeshift;
182 ds->ds_filesystem_size = cpu_to_be64(super->s_size);
183 ds->ds_segment_size = cpu_to_be32(super->s_segsize);
184 ds->ds_bad_seg_reserve = cpu_to_be32(super->s_bad_seg_reserve);
185 ds->ds_feature_incompat = cpu_to_be64(super->s_feature_incompat);
186 ds->ds_feature_ro_compat= cpu_to_be64(super->s_feature_ro_compat);
187 ds->ds_feature_compat = cpu_to_be64(super->s_feature_compat);
188 ds->ds_feature_flags = cpu_to_be64(super->s_feature_flags);
189 ds->ds_root_reserve = cpu_to_be64(super->s_root_reserve);
190 ds->ds_speed_reserve = cpu_to_be64(super->s_speed_reserve);
191 journal_for_each(i)
192 ds->ds_journal_seg[i] = cpu_to_be32(super->s_journal_seg[i]);
193 ds->ds_magic = cpu_to_be64(LOGFS_MAGIC);
194 ds->ds_crc = logfs_crc32(ds, sizeof(*ds),
195 LOGFS_SEGMENT_HEADERSIZE + 12);
196}
197
198static int write_one_sb(struct super_block *sb,
199 struct page *(*find_sb)(struct super_block *sb, u64 *ofs))
200{
201 struct logfs_super *super = logfs_super(sb);
202 struct logfs_disk_super *ds;
203 struct logfs_segment_entry se;
204 struct page *page;
205 u64 ofs;
206 u32 ec, segno;
207 int err;
208
209 page = find_sb(sb, &ofs);
210 if (!page)
211 return -EIO;
212 ds = page_address(page);
213 segno = seg_no(sb, ofs);
214 logfs_get_segment_entry(sb, segno, &se);
215 ec = be32_to_cpu(se.ec_level) >> 4;
216 ec++;
217 logfs_set_segment_erased(sb, segno, ec, 0);
218 logfs_write_ds(sb, ds, segno, ec);
219 err = super->s_devops->write_sb(sb, page);
220 page_cache_release(page);
221 return err;
222}
223
224int logfs_write_sb(struct super_block *sb)
225{
226 struct logfs_super *super = logfs_super(sb);
227 int err;
228
229 /* First superblock */
230 err = write_one_sb(sb, super->s_devops->find_first_sb);
231 if (err)
232 return err;
233
234 /* Last superblock */
235 err = write_one_sb(sb, super->s_devops->find_last_sb);
236 if (err)
237 return err;
238 return 0;
239}
240
241static int ds_cmp(const void *ds0, const void *ds1)
242{
243 size_t len = sizeof(struct logfs_disk_super);
244
245 /* We know the segment headers differ, so ignore them */
246 len -= LOGFS_SEGMENT_HEADERSIZE;
247 ds0 += LOGFS_SEGMENT_HEADERSIZE;
248 ds1 += LOGFS_SEGMENT_HEADERSIZE;
249 return memcmp(ds0, ds1, len);
250}
251
252static int logfs_recover_sb(struct super_block *sb)
253{
254 struct logfs_super *super = logfs_super(sb);
255 struct logfs_disk_super _ds0, *ds0 = &_ds0;
256 struct logfs_disk_super _ds1, *ds1 = &_ds1;
257 int err, valid0, valid1;
258
259 /* read first superblock */
260 err = wbuf_read(sb, super->s_sb_ofs[0], sizeof(*ds0), ds0);
261 if (err)
262 return err;
263 /* read last superblock */
264 err = wbuf_read(sb, super->s_sb_ofs[1], sizeof(*ds1), ds1);
265 if (err)
266 return err;
267 valid0 = logfs_check_ds(ds0) == 0;
268 valid1 = logfs_check_ds(ds1) == 0;
269
270 if (!valid0 && valid1) {
271 printk(KERN_INFO"First superblock is invalid - fixing.\n");
272 return write_one_sb(sb, super->s_devops->find_first_sb);
273 }
274 if (valid0 && !valid1) {
275 printk(KERN_INFO"Last superblock is invalid - fixing.\n");
276 return write_one_sb(sb, super->s_devops->find_last_sb);
277 }
278 if (valid0 && valid1 && ds_cmp(ds0, ds1)) {
279 printk(KERN_INFO"Superblocks don't match - fixing.\n");
280 return write_one_sb(sb, super->s_devops->find_last_sb);
281 }
282 /* If neither is valid now, something's wrong. Didn't we properly
283 * check them before?!? */
284 BUG_ON(!valid0 && !valid1);
285 return 0;
286}
287
288static int logfs_make_writeable(struct super_block *sb)
289{
290 int err;
291
292 /* Repair any broken superblock copies */
293 err = logfs_recover_sb(sb);
294 if (err)
295 return err;
296
297 /* Check areas for trailing unaccounted data */
298 err = logfs_check_areas(sb);
299 if (err)
300 return err;
301
302 err = logfs_open_segfile(sb);
303 if (err)
304 return err;
305
306 /* Do one GC pass before any data gets dirtied */
307 logfs_gc_pass(sb);
308
309 /* after all initializations are done, replay the journal
310 * for rw-mounts, if necessary */
311 err = logfs_replay_journal(sb);
312 if (err)
313 return err;
314
315 return 0;
316}
317
318static int logfs_get_sb_final(struct super_block *sb, struct vfsmount *mnt)
319{
320 struct logfs_super *super = logfs_super(sb);
321 struct inode *rootdir;
322 int err;
323
324 /* root dir */
325 rootdir = logfs_iget(sb, LOGFS_INO_ROOT);
326 if (IS_ERR(rootdir))
327 goto fail;
328
329 sb->s_root = d_alloc_root(rootdir);
330 if (!sb->s_root)
331 goto fail;
332
333 super->s_erase_page = alloc_pages(GFP_KERNEL, 0);
334 if (!super->s_erase_page)
335 goto fail2;
336 memset(page_address(super->s_erase_page), 0xFF, PAGE_SIZE);
337
338 /* FIXME: check for read-only mounts */
339 err = logfs_make_writeable(sb);
340 if (err)
341 goto fail3;
342
343 log_super("LogFS: Finished mounting\n");
344 simple_set_mnt(mnt, sb);
345 return 0;
346
347fail3:
348 __free_page(super->s_erase_page);
349fail2:
350 iput(rootdir);
351fail:
352 iput(logfs_super(sb)->s_master_inode);
353 return -EIO;
354}
355
356int logfs_check_ds(struct logfs_disk_super *ds)
357{
358 struct logfs_segment_header *sh = &ds->ds_sh;
359
360 if (ds->ds_magic != cpu_to_be64(LOGFS_MAGIC))
361 return -EINVAL;
362 if (sh->crc != logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4))
363 return -EINVAL;
364 if (ds->ds_crc != logfs_crc32(ds, sizeof(*ds),
365 LOGFS_SEGMENT_HEADERSIZE + 12))
366 return -EINVAL;
367 return 0;
368}
369
370static struct page *find_super_block(struct super_block *sb)
371{
372 struct logfs_super *super = logfs_super(sb);
373 struct page *first, *last;
374
375 first = super->s_devops->find_first_sb(sb, &super->s_sb_ofs[0]);
376 if (!first || IS_ERR(first))
377 return NULL;
378 last = super->s_devops->find_last_sb(sb, &super->s_sb_ofs[1]);
379 if (!last || IS_ERR(first)) {
380 page_cache_release(first);
381 return NULL;
382 }
383
384 if (!logfs_check_ds(page_address(first))) {
385 page_cache_release(last);
386 return first;
387 }
388
389 /* First one didn't work, try the second superblock */
390 if (!logfs_check_ds(page_address(last))) {
391 page_cache_release(first);
392 return last;
393 }
394
395 /* Neither worked, sorry folks */
396 page_cache_release(first);
397 page_cache_release(last);
398 return NULL;
399}
400
401static int __logfs_read_sb(struct super_block *sb)
402{
403 struct logfs_super *super = logfs_super(sb);
404 struct page *page;
405 struct logfs_disk_super *ds;
406 int i;
407
408 page = find_super_block(sb);
409 if (!page)
410 return -EIO;
411
412 ds = page_address(page);
413 super->s_size = be64_to_cpu(ds->ds_filesystem_size);
414 super->s_root_reserve = be64_to_cpu(ds->ds_root_reserve);
415 super->s_speed_reserve = be64_to_cpu(ds->ds_speed_reserve);
416 super->s_bad_seg_reserve = be32_to_cpu(ds->ds_bad_seg_reserve);
417 super->s_segsize = 1 << ds->ds_segment_shift;
418 super->s_segmask = (1 << ds->ds_segment_shift) - 1;
419 super->s_segshift = ds->ds_segment_shift;
420 sb->s_blocksize = 1 << ds->ds_block_shift;
421 sb->s_blocksize_bits = ds->ds_block_shift;
422 super->s_writesize = 1 << ds->ds_write_shift;
423 super->s_writeshift = ds->ds_write_shift;
424 super->s_no_segs = super->s_size >> super->s_segshift;
425 super->s_no_blocks = super->s_segsize >> sb->s_blocksize_bits;
426 super->s_feature_incompat = be64_to_cpu(ds->ds_feature_incompat);
427 super->s_feature_ro_compat = be64_to_cpu(ds->ds_feature_ro_compat);
428 super->s_feature_compat = be64_to_cpu(ds->ds_feature_compat);
429 super->s_feature_flags = be64_to_cpu(ds->ds_feature_flags);
430
431 journal_for_each(i)
432 super->s_journal_seg[i] = be32_to_cpu(ds->ds_journal_seg[i]);
433
434 super->s_ifile_levels = ds->ds_ifile_levels;
435 super->s_iblock_levels = ds->ds_iblock_levels;
436 super->s_data_levels = ds->ds_data_levels;
437 super->s_total_levels = super->s_ifile_levels + super->s_iblock_levels
438 + super->s_data_levels;
439 page_cache_release(page);
440 return 0;
441}
442
443static int logfs_read_sb(struct super_block *sb, int read_only)
444{
445 struct logfs_super *super = logfs_super(sb);
446 int ret;
447
448 super->s_btree_pool = mempool_create(32, btree_alloc, btree_free, NULL);
449 if (!super->s_btree_pool)
450 return -ENOMEM;
451
452 btree_init_mempool64(&super->s_shadow_tree.new, super->s_btree_pool);
453 btree_init_mempool64(&super->s_shadow_tree.old, super->s_btree_pool);
454
455 ret = logfs_init_mapping(sb);
456 if (ret)
457 return ret;
458
459 ret = __logfs_read_sb(sb);
460 if (ret)
461 return ret;
462
463 if (super->s_feature_incompat & ~LOGFS_FEATURES_INCOMPAT)
464 return -EIO;
465 if ((super->s_feature_ro_compat & ~LOGFS_FEATURES_RO_COMPAT) &&
466 !read_only)
467 return -EIO;
468
469 mutex_init(&super->s_dirop_mutex);
470 mutex_init(&super->s_object_alias_mutex);
471 INIT_LIST_HEAD(&super->s_freeing_list);
472
473 ret = logfs_init_rw(sb);
474 if (ret)
475 return ret;
476
477 ret = logfs_init_areas(sb);
478 if (ret)
479 return ret;
480
481 ret = logfs_init_gc(sb);
482 if (ret)
483 return ret;
484
485 ret = logfs_init_journal(sb);
486 if (ret)
487 return ret;
488
489 return 0;
490}
491
492static void logfs_kill_sb(struct super_block *sb)
493{
494 struct logfs_super *super = logfs_super(sb);
495
496 log_super("LogFS: Start unmounting\n");
497 /* Alias entries slow down mount, so evict as many as possible */
498 sync_filesystem(sb);
499 logfs_write_anchor(sb);
500
501 /*
502 * From this point on alias entries are simply dropped - and any
503 * writes to the object store are considered bugs.
504 */
505 super->s_flags |= LOGFS_SB_FLAG_SHUTDOWN;
506 log_super("LogFS: Now in shutdown\n");
507 generic_shutdown_super(sb);
508
509 BUG_ON(super->s_dirty_used_bytes || super->s_dirty_free_bytes);
510
511 logfs_cleanup_gc(sb);
512 logfs_cleanup_journal(sb);
513 logfs_cleanup_areas(sb);
514 logfs_cleanup_rw(sb);
515 if (super->s_erase_page)
516 __free_page(super->s_erase_page);
517 super->s_devops->put_device(sb);
518 mempool_destroy(super->s_btree_pool);
519 mempool_destroy(super->s_alias_pool);
520 kfree(super);
521 log_super("LogFS: Finished unmounting\n");
522}
523
524int logfs_get_sb_device(struct file_system_type *type, int flags,
525 struct mtd_info *mtd, struct block_device *bdev,
526 const struct logfs_device_ops *devops, struct vfsmount *mnt)
527{
528 struct logfs_super *super;
529 struct super_block *sb;
530 int err = -ENOMEM;
531 static int mount_count;
532
533 log_super("LogFS: Start mount %x\n", mount_count++);
534 super = kzalloc(sizeof(*super), GFP_KERNEL);
535 if (!super)
536 goto err0;
537
538 super->s_mtd = mtd;
539 super->s_bdev = bdev;
540 err = -EINVAL;
541 sb = sget(type, logfs_sb_test, logfs_sb_set, super);
542 if (IS_ERR(sb))
543 goto err0;
544
545 if (sb->s_root) {
546 /* Device is already in use */
547 err = 0;
548 simple_set_mnt(mnt, sb);
549 goto err0;
550 }
551
552 super->s_devops = devops;
553
554 /*
555 * sb->s_maxbytes is limited to 8TB. On 32bit systems, the page cache
556 * only covers 16TB and the upper 8TB are used for indirect blocks.
557 * On 64bit system we could bump up the limit, but that would make
558 * the filesystem incompatible with 32bit systems.
559 */
560 sb->s_maxbytes = (1ull << 43) - 1;
561 sb->s_op = &logfs_super_operations;
562 sb->s_flags = flags | MS_NOATIME;
563
564 err = logfs_read_sb(sb, sb->s_flags & MS_RDONLY);
565 if (err)
566 goto err1;
567
568 sb->s_flags |= MS_ACTIVE;
569 err = logfs_get_sb_final(sb, mnt);
570 if (err)
571 goto err1;
572 return 0;
573
574err1:
575 up_write(&sb->s_umount);
576 deactivate_super(sb);
577 return err;
578err0:
579 kfree(super);
580 //devops->put_device(sb);
581 return err;
582}
583
584static int logfs_get_sb(struct file_system_type *type, int flags,
585 const char *devname, void *data, struct vfsmount *mnt)
586{
587 ulong mtdnr;
588
589 if (!devname)
590 return logfs_get_sb_bdev(type, flags, devname, mnt);
591 if (strncmp(devname, "mtd", 3))
592 return logfs_get_sb_bdev(type, flags, devname, mnt);
593
594 {
595 char *garbage;
596 mtdnr = simple_strtoul(devname+3, &garbage, 0);
597 if (*garbage)
598 return -EINVAL;
599 }
600
601 return logfs_get_sb_mtd(type, flags, mtdnr, mnt);
602}
603
604static struct file_system_type logfs_fs_type = {
605 .owner = THIS_MODULE,
606 .name = "logfs",
607 .get_sb = logfs_get_sb,
608 .kill_sb = logfs_kill_sb,
609 .fs_flags = FS_REQUIRES_DEV,
610
611};
612
613static 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 return register_filesystem(&logfs_fs_type);
630out2:
631 logfs_compr_exit();
632out1:
633 __free_pages(emergency_page, 0);
634 return ret;
635}
636
637static void __exit logfs_exit(void)
638{
639 unregister_filesystem(&logfs_fs_type);
640 logfs_destroy_inode_cache();
641 logfs_compr_exit();
642 __free_pages(emergency_page, 0);
643}
644
645module_init(logfs_init);
646module_exit(logfs_exit);
647
648MODULE_LICENSE("GPL v2");
649MODULE_AUTHOR("Joern Engel <joern@logfs.org>");
650MODULE_DESCRIPTION("scalable flash filesystem");