blob: d651e10a1e9c1e589ed55269c0b1c9bab6488b83 [file] [log] [blame]
Joern Engel5db53f32009-11-20 20:13:39 +01001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090014#include <linux/slab.h>
Joern Engelb8639072010-04-17 19:54:27 +020015#include <linux/blkdev.h>
Joern Engel5db53f32009-11-20 20:13:39 +010016#include <linux/mtd/mtd.h>
17#include <linux/statfs.h>
18#include <linux/buffer_head.h>
19
20static DEFINE_MUTEX(emergency_mutex);
21static struct page *emergency_page;
22
23struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index)
24{
25 filler_t *filler = (filler_t *)mapping->a_ops->readpage;
26 struct page *page;
27 int err;
28
29 page = read_cache_page(mapping, index, filler, NULL);
30 if (page)
31 return page;
32
33 /* No more pages available, switch to emergency page */
34 printk(KERN_INFO"Logfs: Using emergency page\n");
35 mutex_lock(&emergency_mutex);
36 err = filler(NULL, emergency_page);
37 if (err) {
38 mutex_unlock(&emergency_mutex);
39 printk(KERN_EMERG"Logfs: Error reading emergency page\n");
40 return ERR_PTR(err);
41 }
42 return emergency_page;
43}
44
45void emergency_read_end(struct page *page)
46{
47 if (page == emergency_page)
48 mutex_unlock(&emergency_mutex);
49 else
50 page_cache_release(page);
51}
52
53static void dump_segfile(struct super_block *sb)
54{
55 struct logfs_super *super = logfs_super(sb);
56 struct logfs_segment_entry se;
57 u32 segno;
58
59 for (segno = 0; segno < super->s_no_segs; segno++) {
60 logfs_get_segment_entry(sb, segno, &se);
61 printk("%3x: %6x %8x", segno, be32_to_cpu(se.ec_level),
62 be32_to_cpu(se.valid));
63 if (++segno < super->s_no_segs) {
64 logfs_get_segment_entry(sb, segno, &se);
65 printk(" %6x %8x", be32_to_cpu(se.ec_level),
66 be32_to_cpu(se.valid));
67 }
68 if (++segno < super->s_no_segs) {
69 logfs_get_segment_entry(sb, segno, &se);
70 printk(" %6x %8x", be32_to_cpu(se.ec_level),
71 be32_to_cpu(se.valid));
72 }
73 if (++segno < super->s_no_segs) {
74 logfs_get_segment_entry(sb, segno, &se);
75 printk(" %6x %8x", be32_to_cpu(se.ec_level),
76 be32_to_cpu(se.valid));
77 }
78 printk("\n");
79 }
80}
81
82/*
83 * logfs_crash_dump - dump debug information to device
84 *
85 * The LogFS superblock only occupies part of a segment. This function will
86 * write as much debug information as it can gather into the spare space.
87 */
88void logfs_crash_dump(struct super_block *sb)
89{
90 dump_segfile(sb);
91}
92
93/*
94 * TODO: move to lib/string.c
95 */
96/**
97 * memchr_inv - Find a character in an area of memory.
98 * @s: The memory area
99 * @c: The byte to search for
100 * @n: The size of the area.
101 *
102 * returns the address of the first character other than @c, or %NULL
103 * if the whole buffer contains just @c.
104 */
105void *memchr_inv(const void *s, int c, size_t n)
106{
107 const unsigned char *p = s;
108 while (n-- != 0)
109 if ((unsigned char)c != *p++)
110 return (void *)(p - 1);
111
112 return NULL;
113}
114
115/*
116 * FIXME: There should be a reserve for root, similar to ext2.
117 */
118int logfs_statfs(struct dentry *dentry, struct kstatfs *stats)
119{
120 struct super_block *sb = dentry->d_sb;
121 struct logfs_super *super = logfs_super(sb);
122
123 stats->f_type = LOGFS_MAGIC_U32;
124 stats->f_bsize = sb->s_blocksize;
125 stats->f_blocks = super->s_size >> LOGFS_BLOCK_BITS >> 3;
126 stats->f_bfree = super->s_free_bytes >> sb->s_blocksize_bits;
127 stats->f_bavail = super->s_free_bytes >> sb->s_blocksize_bits;
128 stats->f_files = 0;
129 stats->f_ffree = 0;
130 stats->f_namelen = LOGFS_MAX_NAMELEN;
131 return 0;
132}
133
134static int logfs_sb_set(struct super_block *sb, void *_super)
135{
136 struct logfs_super *super = _super;
137
138 sb->s_fs_info = super;
139 sb->s_mtd = super->s_mtd;
140 sb->s_bdev = super->s_bdev;
Joern Engelbba0b5c2010-05-05 22:32:52 +0200141#ifdef CONFIG_BLOCK
Joern Engelb8639072010-04-17 19:54:27 +0200142 if (sb->s_bdev)
143 sb->s_bdi = &bdev_get_queue(sb->s_bdev)->backing_dev_info;
Joern Engelbba0b5c2010-05-05 22:32:52 +0200144#endif
145#ifdef CONFIG_MTD
Joern Engelb8639072010-04-17 19:54:27 +0200146 if (sb->s_mtd)
147 sb->s_bdi = sb->s_mtd->backing_dev_info;
Joern Engelbba0b5c2010-05-05 22:32:52 +0200148#endif
Joern Engel5db53f32009-11-20 20:13:39 +0100149 return 0;
150}
151
152static int logfs_sb_test(struct super_block *sb, void *_super)
153{
154 struct logfs_super *super = _super;
155 struct mtd_info *mtd = super->s_mtd;
156
157 if (mtd && sb->s_mtd == mtd)
158 return 1;
159 if (super->s_bdev && sb->s_bdev == super->s_bdev)
160 return 1;
161 return 0;
162}
163
164static void set_segment_header(struct logfs_segment_header *sh, u8 type,
165 u8 level, u32 segno, u32 ec)
166{
167 sh->pad = 0;
168 sh->type = type;
169 sh->level = level;
170 sh->segno = cpu_to_be32(segno);
171 sh->ec = cpu_to_be32(ec);
172 sh->gec = cpu_to_be64(segno);
173 sh->crc = logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4);
174}
175
176static void logfs_write_ds(struct super_block *sb, struct logfs_disk_super *ds,
177 u32 segno, u32 ec)
178{
179 struct logfs_super *super = logfs_super(sb);
180 struct logfs_segment_header *sh = &ds->ds_sh;
181 int i;
182
183 memset(ds, 0, sizeof(*ds));
184 set_segment_header(sh, SEG_SUPER, 0, segno, ec);
185
186 ds->ds_ifile_levels = super->s_ifile_levels;
187 ds->ds_iblock_levels = super->s_iblock_levels;
188 ds->ds_data_levels = super->s_data_levels; /* XXX: Remove */
189 ds->ds_segment_shift = super->s_segshift;
190 ds->ds_block_shift = sb->s_blocksize_bits;
191 ds->ds_write_shift = super->s_writeshift;
192 ds->ds_filesystem_size = cpu_to_be64(super->s_size);
193 ds->ds_segment_size = cpu_to_be32(super->s_segsize);
194 ds->ds_bad_seg_reserve = cpu_to_be32(super->s_bad_seg_reserve);
195 ds->ds_feature_incompat = cpu_to_be64(super->s_feature_incompat);
196 ds->ds_feature_ro_compat= cpu_to_be64(super->s_feature_ro_compat);
197 ds->ds_feature_compat = cpu_to_be64(super->s_feature_compat);
198 ds->ds_feature_flags = cpu_to_be64(super->s_feature_flags);
199 ds->ds_root_reserve = cpu_to_be64(super->s_root_reserve);
200 ds->ds_speed_reserve = cpu_to_be64(super->s_speed_reserve);
201 journal_for_each(i)
202 ds->ds_journal_seg[i] = cpu_to_be32(super->s_journal_seg[i]);
203 ds->ds_magic = cpu_to_be64(LOGFS_MAGIC);
204 ds->ds_crc = logfs_crc32(ds, sizeof(*ds),
205 LOGFS_SEGMENT_HEADERSIZE + 12);
206}
207
208static int write_one_sb(struct super_block *sb,
209 struct page *(*find_sb)(struct super_block *sb, u64 *ofs))
210{
211 struct logfs_super *super = logfs_super(sb);
212 struct logfs_disk_super *ds;
213 struct logfs_segment_entry se;
214 struct page *page;
215 u64 ofs;
216 u32 ec, segno;
217 int err;
218
219 page = find_sb(sb, &ofs);
220 if (!page)
221 return -EIO;
222 ds = page_address(page);
223 segno = seg_no(sb, ofs);
224 logfs_get_segment_entry(sb, segno, &se);
225 ec = be32_to_cpu(se.ec_level) >> 4;
226 ec++;
227 logfs_set_segment_erased(sb, segno, ec, 0);
228 logfs_write_ds(sb, ds, segno, ec);
229 err = super->s_devops->write_sb(sb, page);
230 page_cache_release(page);
231 return err;
232}
233
234int logfs_write_sb(struct super_block *sb)
235{
236 struct logfs_super *super = logfs_super(sb);
237 int err;
238
239 /* First superblock */
240 err = write_one_sb(sb, super->s_devops->find_first_sb);
241 if (err)
242 return err;
243
244 /* Last superblock */
245 err = write_one_sb(sb, super->s_devops->find_last_sb);
246 if (err)
247 return err;
248 return 0;
249}
250
251static int ds_cmp(const void *ds0, const void *ds1)
252{
253 size_t len = sizeof(struct logfs_disk_super);
254
255 /* We know the segment headers differ, so ignore them */
256 len -= LOGFS_SEGMENT_HEADERSIZE;
257 ds0 += LOGFS_SEGMENT_HEADERSIZE;
258 ds1 += LOGFS_SEGMENT_HEADERSIZE;
259 return memcmp(ds0, ds1, len);
260}
261
262static int logfs_recover_sb(struct super_block *sb)
263{
264 struct logfs_super *super = logfs_super(sb);
265 struct logfs_disk_super _ds0, *ds0 = &_ds0;
266 struct logfs_disk_super _ds1, *ds1 = &_ds1;
267 int err, valid0, valid1;
268
269 /* read first superblock */
270 err = wbuf_read(sb, super->s_sb_ofs[0], sizeof(*ds0), ds0);
271 if (err)
272 return err;
273 /* read last superblock */
274 err = wbuf_read(sb, super->s_sb_ofs[1], sizeof(*ds1), ds1);
275 if (err)
276 return err;
277 valid0 = logfs_check_ds(ds0) == 0;
278 valid1 = logfs_check_ds(ds1) == 0;
279
280 if (!valid0 && valid1) {
281 printk(KERN_INFO"First superblock is invalid - fixing.\n");
282 return write_one_sb(sb, super->s_devops->find_first_sb);
283 }
284 if (valid0 && !valid1) {
285 printk(KERN_INFO"Last superblock is invalid - fixing.\n");
286 return write_one_sb(sb, super->s_devops->find_last_sb);
287 }
288 if (valid0 && valid1 && ds_cmp(ds0, ds1)) {
289 printk(KERN_INFO"Superblocks don't match - fixing.\n");
Joern Engelfaaa27a2010-03-26 10:18:36 +0100290 return logfs_write_sb(sb);
Joern Engel5db53f32009-11-20 20:13:39 +0100291 }
292 /* If neither is valid now, something's wrong. Didn't we properly
293 * check them before?!? */
294 BUG_ON(!valid0 && !valid1);
295 return 0;
296}
297
298static int logfs_make_writeable(struct super_block *sb)
299{
300 int err;
301
Joern Engel49137f22010-03-16 21:46:15 +0100302 err = logfs_open_segfile(sb);
303 if (err)
304 return err;
305
Joern Engel5db53f32009-11-20 20:13:39 +0100306 /* Repair any broken superblock copies */
307 err = logfs_recover_sb(sb);
308 if (err)
309 return err;
310
311 /* Check areas for trailing unaccounted data */
312 err = logfs_check_areas(sb);
313 if (err)
314 return err;
315
Joern Engel5db53f32009-11-20 20:13:39 +0100316 /* Do one GC pass before any data gets dirtied */
317 logfs_gc_pass(sb);
318
319 /* after all initializations are done, replay the journal
320 * for rw-mounts, if necessary */
321 err = logfs_replay_journal(sb);
322 if (err)
323 return err;
324
325 return 0;
326}
327
328static int logfs_get_sb_final(struct super_block *sb, struct vfsmount *mnt)
329{
Joern Engel94215022010-03-04 21:30:58 +0100330 struct logfs_super *super = logfs_super(sb);
Joern Engel5db53f32009-11-20 20:13:39 +0100331 struct inode *rootdir;
332 int err;
333
334 /* root dir */
335 rootdir = logfs_iget(sb, LOGFS_INO_ROOT);
336 if (IS_ERR(rootdir))
337 goto fail;
338
339 sb->s_root = d_alloc_root(rootdir);
Al Viro26562442010-04-28 20:57:02 -0400340 if (!sb->s_root) {
341 iput(rootdir);
342 goto fail;
343 }
Joern Engel5db53f32009-11-20 20:13:39 +0100344
Joern Engel94215022010-03-04 21:30:58 +0100345 super->s_erase_page = alloc_pages(GFP_KERNEL, 0);
346 if (!super->s_erase_page)
Al Viro26562442010-04-28 20:57:02 -0400347 goto fail;
Joern Engel94215022010-03-04 21:30:58 +0100348 memset(page_address(super->s_erase_page), 0xFF, PAGE_SIZE);
349
Joern Engel5db53f32009-11-20 20:13:39 +0100350 /* FIXME: check for read-only mounts */
351 err = logfs_make_writeable(sb);
352 if (err)
Al Viro26562442010-04-28 20:57:02 -0400353 goto fail1;
Joern Engel5db53f32009-11-20 20:13:39 +0100354
355 log_super("LogFS: Finished mounting\n");
356 simple_set_mnt(mnt, sb);
357 return 0;
358
Al Viro26562442010-04-28 20:57:02 -0400359fail1:
Joern Engel94215022010-03-04 21:30:58 +0100360 __free_page(super->s_erase_page);
Joern Engel5db53f32009-11-20 20:13:39 +0100361fail:
362 iput(logfs_super(sb)->s_master_inode);
363 return -EIO;
364}
365
366int logfs_check_ds(struct logfs_disk_super *ds)
367{
368 struct logfs_segment_header *sh = &ds->ds_sh;
369
370 if (ds->ds_magic != cpu_to_be64(LOGFS_MAGIC))
371 return -EINVAL;
372 if (sh->crc != logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4))
373 return -EINVAL;
374 if (ds->ds_crc != logfs_crc32(ds, sizeof(*ds),
375 LOGFS_SEGMENT_HEADERSIZE + 12))
376 return -EINVAL;
377 return 0;
378}
379
380static struct page *find_super_block(struct super_block *sb)
381{
382 struct logfs_super *super = logfs_super(sb);
383 struct page *first, *last;
384
385 first = super->s_devops->find_first_sb(sb, &super->s_sb_ofs[0]);
386 if (!first || IS_ERR(first))
387 return NULL;
388 last = super->s_devops->find_last_sb(sb, &super->s_sb_ofs[1]);
Dan Carpenter3272c8a2010-04-21 12:33:54 +0200389 if (!last || IS_ERR(last)) {
Joern Engel5db53f32009-11-20 20:13:39 +0100390 page_cache_release(first);
391 return NULL;
392 }
393
394 if (!logfs_check_ds(page_address(first))) {
395 page_cache_release(last);
396 return first;
397 }
398
399 /* First one didn't work, try the second superblock */
400 if (!logfs_check_ds(page_address(last))) {
401 page_cache_release(first);
402 return last;
403 }
404
405 /* Neither worked, sorry folks */
406 page_cache_release(first);
407 page_cache_release(last);
408 return NULL;
409}
410
411static int __logfs_read_sb(struct super_block *sb)
412{
413 struct logfs_super *super = logfs_super(sb);
414 struct page *page;
415 struct logfs_disk_super *ds;
416 int i;
417
418 page = find_super_block(sb);
419 if (!page)
Joern Engelad342632010-04-27 13:45:31 +0200420 return -EINVAL;
Joern Engel5db53f32009-11-20 20:13:39 +0100421
422 ds = page_address(page);
423 super->s_size = be64_to_cpu(ds->ds_filesystem_size);
424 super->s_root_reserve = be64_to_cpu(ds->ds_root_reserve);
425 super->s_speed_reserve = be64_to_cpu(ds->ds_speed_reserve);
426 super->s_bad_seg_reserve = be32_to_cpu(ds->ds_bad_seg_reserve);
427 super->s_segsize = 1 << ds->ds_segment_shift;
428 super->s_segmask = (1 << ds->ds_segment_shift) - 1;
429 super->s_segshift = ds->ds_segment_shift;
430 sb->s_blocksize = 1 << ds->ds_block_shift;
431 sb->s_blocksize_bits = ds->ds_block_shift;
432 super->s_writesize = 1 << ds->ds_write_shift;
433 super->s_writeshift = ds->ds_write_shift;
434 super->s_no_segs = super->s_size >> super->s_segshift;
435 super->s_no_blocks = super->s_segsize >> sb->s_blocksize_bits;
436 super->s_feature_incompat = be64_to_cpu(ds->ds_feature_incompat);
437 super->s_feature_ro_compat = be64_to_cpu(ds->ds_feature_ro_compat);
438 super->s_feature_compat = be64_to_cpu(ds->ds_feature_compat);
439 super->s_feature_flags = be64_to_cpu(ds->ds_feature_flags);
440
441 journal_for_each(i)
442 super->s_journal_seg[i] = be32_to_cpu(ds->ds_journal_seg[i]);
443
444 super->s_ifile_levels = ds->ds_ifile_levels;
445 super->s_iblock_levels = ds->ds_iblock_levels;
446 super->s_data_levels = ds->ds_data_levels;
447 super->s_total_levels = super->s_ifile_levels + super->s_iblock_levels
448 + super->s_data_levels;
449 page_cache_release(page);
450 return 0;
451}
452
Joern Engel6a08ab82010-03-05 16:07:04 +0100453static int logfs_read_sb(struct super_block *sb, int read_only)
Joern Engel5db53f32009-11-20 20:13:39 +0100454{
455 struct logfs_super *super = logfs_super(sb);
456 int ret;
457
458 super->s_btree_pool = mempool_create(32, btree_alloc, btree_free, NULL);
459 if (!super->s_btree_pool)
460 return -ENOMEM;
461
462 btree_init_mempool64(&super->s_shadow_tree.new, super->s_btree_pool);
463 btree_init_mempool64(&super->s_shadow_tree.old, super->s_btree_pool);
Joern Engel032d8f72010-04-13 17:46:37 +0200464 btree_init_mempool32(&super->s_shadow_tree.segment_map,
465 super->s_btree_pool);
Joern Engel5db53f32009-11-20 20:13:39 +0100466
467 ret = logfs_init_mapping(sb);
468 if (ret)
469 return ret;
470
471 ret = __logfs_read_sb(sb);
472 if (ret)
473 return ret;
474
Joern Engel6a08ab82010-03-05 16:07:04 +0100475 if (super->s_feature_incompat & ~LOGFS_FEATURES_INCOMPAT)
476 return -EIO;
477 if ((super->s_feature_ro_compat & ~LOGFS_FEATURES_RO_COMPAT) &&
478 !read_only)
479 return -EIO;
480
Joern Engel5db53f32009-11-20 20:13:39 +0100481 mutex_init(&super->s_dirop_mutex);
482 mutex_init(&super->s_object_alias_mutex);
483 INIT_LIST_HEAD(&super->s_freeing_list);
484
485 ret = logfs_init_rw(sb);
486 if (ret)
487 return ret;
488
489 ret = logfs_init_areas(sb);
490 if (ret)
491 return ret;
492
493 ret = logfs_init_gc(sb);
494 if (ret)
495 return ret;
496
497 ret = logfs_init_journal(sb);
498 if (ret)
499 return ret;
500
501 return 0;
502}
503
504static void logfs_kill_sb(struct super_block *sb)
505{
506 struct logfs_super *super = logfs_super(sb);
507
508 log_super("LogFS: Start unmounting\n");
509 /* Alias entries slow down mount, so evict as many as possible */
510 sync_filesystem(sb);
Joern Engelc6d38302010-03-04 21:36:19 +0100511 logfs_write_anchor(sb);
Joern Engel5db53f32009-11-20 20:13:39 +0100512
513 /*
514 * From this point on alias entries are simply dropped - and any
515 * writes to the object store are considered bugs.
516 */
517 super->s_flags |= LOGFS_SB_FLAG_SHUTDOWN;
518 log_super("LogFS: Now in shutdown\n");
519 generic_shutdown_super(sb);
520
521 BUG_ON(super->s_dirty_used_bytes || super->s_dirty_free_bytes);
522
523 logfs_cleanup_gc(sb);
524 logfs_cleanup_journal(sb);
525 logfs_cleanup_areas(sb);
526 logfs_cleanup_rw(sb);
Joern Engel94215022010-03-04 21:30:58 +0100527 if (super->s_erase_page)
528 __free_page(super->s_erase_page);
Joern Engel5db53f32009-11-20 20:13:39 +0100529 super->s_devops->put_device(sb);
Joern Engel1f1b0002010-04-15 08:03:57 +0200530 logfs_mempool_destroy(super->s_btree_pool);
531 logfs_mempool_destroy(super->s_alias_pool);
Joern Engel5db53f32009-11-20 20:13:39 +0100532 kfree(super);
533 log_super("LogFS: Finished unmounting\n");
534}
535
536int logfs_get_sb_device(struct file_system_type *type, int flags,
537 struct mtd_info *mtd, struct block_device *bdev,
538 const struct logfs_device_ops *devops, struct vfsmount *mnt)
539{
540 struct logfs_super *super;
541 struct super_block *sb;
542 int err = -ENOMEM;
543 static int mount_count;
544
545 log_super("LogFS: Start mount %x\n", mount_count++);
546 super = kzalloc(sizeof(*super), GFP_KERNEL);
547 if (!super)
548 goto err0;
549
550 super->s_mtd = mtd;
551 super->s_bdev = bdev;
552 err = -EINVAL;
553 sb = sget(type, logfs_sb_test, logfs_sb_set, super);
554 if (IS_ERR(sb))
555 goto err0;
556
557 if (sb->s_root) {
558 /* Device is already in use */
559 err = 0;
560 simple_set_mnt(mnt, sb);
561 goto err0;
562 }
563
564 super->s_devops = devops;
565
566 /*
567 * sb->s_maxbytes is limited to 8TB. On 32bit systems, the page cache
568 * only covers 16TB and the upper 8TB are used for indirect blocks.
569 * On 64bit system we could bump up the limit, but that would make
570 * the filesystem incompatible with 32bit systems.
571 */
572 sb->s_maxbytes = (1ull << 43) - 1;
573 sb->s_op = &logfs_super_operations;
574 sb->s_flags = flags | MS_NOATIME;
575
Joern Engel6a08ab82010-03-05 16:07:04 +0100576 err = logfs_read_sb(sb, sb->s_flags & MS_RDONLY);
Joern Engel5db53f32009-11-20 20:13:39 +0100577 if (err)
578 goto err1;
579
580 sb->s_flags |= MS_ACTIVE;
581 err = logfs_get_sb_final(sb, mnt);
582 if (err)
583 goto err1;
584 return 0;
585
586err1:
Joern Engel6f2e9e62010-03-26 14:50:08 +0100587 deactivate_locked_super(sb);
Joern Engel5db53f32009-11-20 20:13:39 +0100588 return err;
589err0:
590 kfree(super);
591 //devops->put_device(sb);
592 return err;
593}
594
595static int logfs_get_sb(struct file_system_type *type, int flags,
596 const char *devname, void *data, struct vfsmount *mnt)
597{
598 ulong mtdnr;
599
600 if (!devname)
601 return logfs_get_sb_bdev(type, flags, devname, mnt);
602 if (strncmp(devname, "mtd", 3))
603 return logfs_get_sb_bdev(type, flags, devname, mnt);
604
605 {
606 char *garbage;
607 mtdnr = simple_strtoul(devname+3, &garbage, 0);
608 if (*garbage)
609 return -EINVAL;
610 }
611
612 return logfs_get_sb_mtd(type, flags, mtdnr, mnt);
613}
614
615static struct file_system_type logfs_fs_type = {
616 .owner = THIS_MODULE,
617 .name = "logfs",
618 .get_sb = logfs_get_sb,
619 .kill_sb = logfs_kill_sb,
620 .fs_flags = FS_REQUIRES_DEV,
621
622};
623
624static int __init logfs_init(void)
625{
626 int ret;
627
628 emergency_page = alloc_pages(GFP_KERNEL, 0);
629 if (!emergency_page)
630 return -ENOMEM;
631
632 ret = logfs_compr_init();
633 if (ret)
634 goto out1;
635
636 ret = logfs_init_inode_cache();
637 if (ret)
638 goto out2;
639
640 return register_filesystem(&logfs_fs_type);
641out2:
642 logfs_compr_exit();
643out1:
644 __free_pages(emergency_page, 0);
645 return ret;
646}
647
648static void __exit logfs_exit(void)
649{
650 unregister_filesystem(&logfs_fs_type);
651 logfs_destroy_inode_cache();
652 logfs_compr_exit();
653 __free_pages(emergency_page, 0);
654}
655
656module_init(logfs_init);
657module_exit(logfs_exit);
658
659MODULE_LICENSE("GPL v2");
660MODULE_AUTHOR("Joern Engel <joern@logfs.org>");
661MODULE_DESCRIPTION("scalable flash filesystem");