ASoC: Remove references to corgi and spitz from machine driver document
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / logfs / super.c
blobe795c234ea33592e12cb264c0c8c84d2146f29c3
1 /*
2 * fs/logfs/super.c
4 * As should be obvious for Linux kernel code, license is GPLv2
6 * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
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.
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>
21 static DEFINE_MUTEX(emergency_mutex);
22 static struct page *emergency_page;
24 struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index)
26 filler_t *filler = (filler_t *)mapping->a_ops->readpage;
27 struct page *page;
28 int err;
30 page = read_cache_page(mapping, index, filler, NULL);
31 if (page)
32 return page;
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);
43 return emergency_page;
46 void emergency_read_end(struct page *page)
48 if (page == emergency_page)
49 mutex_unlock(&emergency_mutex);
50 else
51 page_cache_release(page);
54 static void dump_segfile(struct super_block *sb)
56 struct logfs_super *super = logfs_super(sb);
57 struct logfs_segment_entry se;
58 u32 segno;
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));
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));
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));
79 printk("\n");
84 * logfs_crash_dump - dump debug information to device
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.
89 void logfs_crash_dump(struct super_block *sb)
91 dump_segfile(sb);
95 * FIXME: There should be a reserve for root, similar to ext2.
97 int logfs_statfs(struct dentry *dentry, struct kstatfs *stats)
99 struct super_block *sb = dentry->d_sb;
100 struct logfs_super *super = logfs_super(sb);
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;
113 static int logfs_sb_set(struct super_block *sb, void *_super)
115 struct logfs_super *super = _super;
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;
131 static int logfs_sb_test(struct super_block *sb, void *_super)
133 struct logfs_super *super = _super;
134 struct mtd_info *mtd = super->s_mtd;
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;
143 static void set_segment_header(struct logfs_segment_header *sh, u8 type,
144 u8 level, u32 segno, u32 ec)
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);
155 static void logfs_write_ds(struct super_block *sb, struct logfs_disk_super *ds,
156 u32 segno, u32 ec)
158 struct logfs_super *super = logfs_super(sb);
159 struct logfs_segment_header *sh = &ds->ds_sh;
160 int i;
162 memset(ds, 0, sizeof(*ds));
163 set_segment_header(sh, SEG_SUPER, 0, segno, ec);
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);
187 static int write_one_sb(struct super_block *sb,
188 struct page *(*find_sb)(struct super_block *sb, u64 *ofs))
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;
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;
213 int logfs_write_sb(struct super_block *sb)
215 struct logfs_super *super = logfs_super(sb);
216 int err;
218 /* First superblock */
219 err = write_one_sb(sb, super->s_devops->find_first_sb);
220 if (err)
221 return err;
223 /* Last superblock */
224 err = write_one_sb(sb, super->s_devops->find_last_sb);
225 if (err)
226 return err;
227 return 0;
230 static int ds_cmp(const void *ds0, const void *ds1)
232 size_t len = sizeof(struct logfs_disk_super);
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);
241 static int logfs_recover_sb(struct super_block *sb)
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;
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;
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);
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);
267 if (valid0 && valid1 && ds_cmp(ds0, ds1)) {
268 printk(KERN_INFO"Superblocks don't match - fixing.\n");
269 return logfs_write_sb(sb);
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;
277 static int logfs_make_writeable(struct super_block *sb)
279 int err;
281 err = logfs_open_segfile(sb);
282 if (err)
283 return err;
285 /* Repair any broken superblock copies */
286 err = logfs_recover_sb(sb);
287 if (err)
288 return err;
290 /* Check areas for trailing unaccounted data */
291 err = logfs_check_areas(sb);
292 if (err)
293 return err;
295 /* Do one GC pass before any data gets dirtied */
296 logfs_gc_pass(sb);
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;
304 return 0;
307 static int logfs_get_sb_final(struct super_block *sb)
309 struct logfs_super *super = logfs_super(sb);
310 struct inode *rootdir;
311 int err;
313 /* root dir */
314 rootdir = logfs_iget(sb, LOGFS_INO_ROOT);
315 if (IS_ERR(rootdir))
316 goto fail;
318 sb->s_root = d_alloc_root(rootdir);
319 if (!sb->s_root) {
320 iput(rootdir);
321 goto fail;
324 /* at that point we know that ->put_super() will be called */
325 super->s_erase_page = alloc_pages(GFP_KERNEL, 0);
326 if (!super->s_erase_page)
327 return -ENOMEM;
328 memset(page_address(super->s_erase_page), 0xFF, PAGE_SIZE);
330 /* FIXME: check for read-only mounts */
331 err = logfs_make_writeable(sb);
332 if (err) {
333 __free_page(super->s_erase_page);
334 return err;
337 log_super("LogFS: Finished mounting\n");
338 return 0;
340 fail:
341 iput(super->s_master_inode);
342 iput(super->s_segfile_inode);
343 iput(super->s_mapping_inode);
344 return -EIO;
347 int logfs_check_ds(struct logfs_disk_super *ds)
349 struct logfs_segment_header *sh = &ds->ds_sh;
351 if (ds->ds_magic != cpu_to_be64(LOGFS_MAGIC))
352 return -EINVAL;
353 if (sh->crc != logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4))
354 return -EINVAL;
355 if (ds->ds_crc != logfs_crc32(ds, sizeof(*ds),
356 LOGFS_SEGMENT_HEADERSIZE + 12))
357 return -EINVAL;
358 return 0;
361 static struct page *find_super_block(struct super_block *sb)
363 struct logfs_super *super = logfs_super(sb);
364 struct page *first, *last;
366 first = super->s_devops->find_first_sb(sb, &super->s_sb_ofs[0]);
367 if (!first || IS_ERR(first))
368 return NULL;
369 last = super->s_devops->find_last_sb(sb, &super->s_sb_ofs[1]);
370 if (!last || IS_ERR(last)) {
371 page_cache_release(first);
372 return NULL;
375 if (!logfs_check_ds(page_address(first))) {
376 page_cache_release(last);
377 return first;
380 /* First one didn't work, try the second superblock */
381 if (!logfs_check_ds(page_address(last))) {
382 page_cache_release(first);
383 return last;
386 /* Neither worked, sorry folks */
387 page_cache_release(first);
388 page_cache_release(last);
389 return NULL;
392 static int __logfs_read_sb(struct super_block *sb)
394 struct logfs_super *super = logfs_super(sb);
395 struct page *page;
396 struct logfs_disk_super *ds;
397 int i;
399 page = find_super_block(sb);
400 if (!page)
401 return -EINVAL;
403 ds = page_address(page);
404 super->s_size = be64_to_cpu(ds->ds_filesystem_size);
405 super->s_root_reserve = be64_to_cpu(ds->ds_root_reserve);
406 super->s_speed_reserve = be64_to_cpu(ds->ds_speed_reserve);
407 super->s_bad_seg_reserve = be32_to_cpu(ds->ds_bad_seg_reserve);
408 super->s_segsize = 1 << ds->ds_segment_shift;
409 super->s_segmask = (1 << ds->ds_segment_shift) - 1;
410 super->s_segshift = ds->ds_segment_shift;
411 sb->s_blocksize = 1 << ds->ds_block_shift;
412 sb->s_blocksize_bits = ds->ds_block_shift;
413 super->s_writesize = 1 << ds->ds_write_shift;
414 super->s_writeshift = ds->ds_write_shift;
415 super->s_no_segs = super->s_size >> super->s_segshift;
416 super->s_no_blocks = super->s_segsize >> sb->s_blocksize_bits;
417 super->s_feature_incompat = be64_to_cpu(ds->ds_feature_incompat);
418 super->s_feature_ro_compat = be64_to_cpu(ds->ds_feature_ro_compat);
419 super->s_feature_compat = be64_to_cpu(ds->ds_feature_compat);
420 super->s_feature_flags = be64_to_cpu(ds->ds_feature_flags);
422 journal_for_each(i)
423 super->s_journal_seg[i] = be32_to_cpu(ds->ds_journal_seg[i]);
425 super->s_ifile_levels = ds->ds_ifile_levels;
426 super->s_iblock_levels = ds->ds_iblock_levels;
427 super->s_data_levels = ds->ds_data_levels;
428 super->s_total_levels = super->s_ifile_levels + super->s_iblock_levels
429 + super->s_data_levels;
430 page_cache_release(page);
431 return 0;
434 static int logfs_read_sb(struct super_block *sb, int read_only)
436 struct logfs_super *super = logfs_super(sb);
437 int ret;
439 super->s_btree_pool = mempool_create(32, btree_alloc, btree_free, NULL);
440 if (!super->s_btree_pool)
441 return -ENOMEM;
443 btree_init_mempool64(&super->s_shadow_tree.new, super->s_btree_pool);
444 btree_init_mempool64(&super->s_shadow_tree.old, super->s_btree_pool);
445 btree_init_mempool32(&super->s_shadow_tree.segment_map,
446 super->s_btree_pool);
448 ret = logfs_init_mapping(sb);
449 if (ret)
450 return ret;
452 ret = __logfs_read_sb(sb);
453 if (ret)
454 return ret;
456 if (super->s_feature_incompat & ~LOGFS_FEATURES_INCOMPAT)
457 return -EIO;
458 if ((super->s_feature_ro_compat & ~LOGFS_FEATURES_RO_COMPAT) &&
459 !read_only)
460 return -EIO;
462 ret = logfs_init_rw(sb);
463 if (ret)
464 return ret;
466 ret = logfs_init_areas(sb);
467 if (ret)
468 return ret;
470 ret = logfs_init_gc(sb);
471 if (ret)
472 return ret;
474 ret = logfs_init_journal(sb);
475 if (ret)
476 return ret;
478 return 0;
481 static void logfs_kill_sb(struct super_block *sb)
483 struct logfs_super *super = logfs_super(sb);
485 log_super("LogFS: Start unmounting\n");
486 /* Alias entries slow down mount, so evict as many as possible */
487 sync_filesystem(sb);
488 logfs_write_anchor(sb);
491 * From this point on alias entries are simply dropped - and any
492 * writes to the object store are considered bugs.
494 super->s_flags |= LOGFS_SB_FLAG_SHUTDOWN;
495 log_super("LogFS: Now in shutdown\n");
496 generic_shutdown_super(sb);
498 BUG_ON(super->s_dirty_used_bytes || super->s_dirty_free_bytes);
500 logfs_cleanup_gc(sb);
501 logfs_cleanup_journal(sb);
502 logfs_cleanup_areas(sb);
503 logfs_cleanup_rw(sb);
504 if (super->s_erase_page)
505 __free_page(super->s_erase_page);
506 super->s_devops->put_device(super);
507 logfs_mempool_destroy(super->s_btree_pool);
508 logfs_mempool_destroy(super->s_alias_pool);
509 kfree(super);
510 log_super("LogFS: Finished unmounting\n");
513 static struct dentry *logfs_get_sb_device(struct logfs_super *super,
514 struct file_system_type *type, int flags)
516 struct super_block *sb;
517 int err = -ENOMEM;
518 static int mount_count;
520 log_super("LogFS: Start mount %x\n", mount_count++);
522 err = -EINVAL;
523 sb = sget(type, logfs_sb_test, logfs_sb_set, super);
524 if (IS_ERR(sb)) {
525 super->s_devops->put_device(super);
526 kfree(super);
527 return ERR_CAST(sb);
530 if (sb->s_root) {
531 /* Device is already in use */
532 super->s_devops->put_device(super);
533 kfree(super);
534 return dget(sb->s_root);
538 * sb->s_maxbytes is limited to 8TB. On 32bit systems, the page cache
539 * only covers 16TB and the upper 8TB are used for indirect blocks.
540 * On 64bit system we could bump up the limit, but that would make
541 * the filesystem incompatible with 32bit systems.
543 sb->s_maxbytes = (1ull << 43) - 1;
544 sb->s_op = &logfs_super_operations;
545 sb->s_flags = flags | MS_NOATIME;
547 err = logfs_read_sb(sb, sb->s_flags & MS_RDONLY);
548 if (err)
549 goto err1;
551 sb->s_flags |= MS_ACTIVE;
552 err = logfs_get_sb_final(sb);
553 if (err) {
554 deactivate_locked_super(sb);
555 return ERR_PTR(err);
557 return dget(sb->s_root);
559 err1:
560 /* no ->s_root, no ->put_super() */
561 iput(super->s_master_inode);
562 iput(super->s_segfile_inode);
563 iput(super->s_mapping_inode);
564 deactivate_locked_super(sb);
565 return ERR_PTR(err);
568 static struct dentry *logfs_mount(struct file_system_type *type, int flags,
569 const char *devname, void *data)
571 ulong mtdnr;
572 struct logfs_super *super;
573 int err;
575 super = kzalloc(sizeof(*super), GFP_KERNEL);
576 if (!super)
577 return ERR_PTR(-ENOMEM);
579 mutex_init(&super->s_dirop_mutex);
580 mutex_init(&super->s_object_alias_mutex);
581 INIT_LIST_HEAD(&super->s_freeing_list);
583 if (!devname)
584 err = logfs_get_sb_bdev(super, type, devname);
585 else if (strncmp(devname, "mtd", 3))
586 err = logfs_get_sb_bdev(super, type, devname);
587 else {
588 char *garbage;
589 mtdnr = simple_strtoul(devname+3, &garbage, 0);
590 if (*garbage)
591 err = -EINVAL;
592 else
593 err = logfs_get_sb_mtd(super, mtdnr);
596 if (err) {
597 kfree(super);
598 return ERR_PTR(err);
601 return logfs_get_sb_device(super, type, flags);
604 static struct file_system_type logfs_fs_type = {
605 .owner = THIS_MODULE,
606 .name = "logfs",
607 .mount = logfs_mount,
608 .kill_sb = logfs_kill_sb,
609 .fs_flags = FS_REQUIRES_DEV,
613 static int __init logfs_init(void)
615 int ret;
617 emergency_page = alloc_pages(GFP_KERNEL, 0);
618 if (!emergency_page)
619 return -ENOMEM;
621 ret = logfs_compr_init();
622 if (ret)
623 goto out1;
625 ret = logfs_init_inode_cache();
626 if (ret)
627 goto out2;
629 return register_filesystem(&logfs_fs_type);
630 out2:
631 logfs_compr_exit();
632 out1:
633 __free_pages(emergency_page, 0);
634 return ret;
637 static void __exit logfs_exit(void)
639 unregister_filesystem(&logfs_fs_type);
640 logfs_destroy_inode_cache();
641 logfs_compr_exit();
642 __free_pages(emergency_page, 0);
645 module_init(logfs_init);
646 module_exit(logfs_exit);
648 MODULE_LICENSE("GPL v2");
649 MODULE_AUTHOR("Joern Engel <joern@logfs.org>");
650 MODULE_DESCRIPTION("scalable flash filesystem");