xref: /linux/fs/affs/super.c (revision f4cdf7ca9a1fdcca413157df19753f388a5a224e)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/fs/affs/inode.c
4  *
5  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
6  *
7  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
8  *
9  *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
10  *
11  *  (C) 1991  Linus Torvalds - minix filesystem
12  */
13 
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/statfs.h>
17 #include <linux/fs_parser.h>
18 #include <linux/fs_context.h>
19 #include <linux/magic.h>
20 #include <linux/sched.h>
21 #include <linux/cred.h>
22 #include <linux/slab.h>
23 #include <linux/writeback.h>
24 #include <linux/blkdev.h>
25 #include <linux/seq_file.h>
26 #include <linux/iversion.h>
27 #include "affs.h"
28 
29 static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
30 static int affs_show_options(struct seq_file *m, struct dentry *root);
31 
32 static void
33 affs_commit_super(struct super_block *sb, int wait)
34 {
35 	struct affs_sb_info *sbi = AFFS_SB(sb);
36 	struct buffer_head *bh = sbi->s_root_bh;
37 	struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);
38 
39 	lock_buffer(bh);
40 	affs_secs_to_datestamp(ktime_get_real_seconds(), &tail->disk_change);
41 	affs_fix_checksum(sb, bh);
42 	unlock_buffer(bh);
43 
44 	mark_buffer_dirty(bh);
45 	if (wait)
46 		sync_dirty_buffer(bh);
47 }
48 
49 static void
50 affs_put_super(struct super_block *sb)
51 {
52 	struct affs_sb_info *sbi = AFFS_SB(sb);
53 	pr_debug("%s()\n", __func__);
54 
55 	cancel_delayed_work_sync(&sbi->sb_work);
56 }
57 
58 static int
59 affs_sync_fs(struct super_block *sb, int wait)
60 {
61 	affs_commit_super(sb, wait);
62 	return 0;
63 }
64 
65 static void flush_superblock(struct work_struct *work)
66 {
67 	struct affs_sb_info *sbi;
68 	struct super_block *sb;
69 
70 	sbi = container_of(work, struct affs_sb_info, sb_work.work);
71 	sb = sbi->sb;
72 
73 	spin_lock(&sbi->work_lock);
74 	sbi->work_queued = 0;
75 	spin_unlock(&sbi->work_lock);
76 
77 	affs_commit_super(sb, 1);
78 }
79 
80 void affs_mark_sb_dirty(struct super_block *sb)
81 {
82 	struct affs_sb_info *sbi = AFFS_SB(sb);
83 	unsigned long delay;
84 
85 	if (sb_rdonly(sb))
86 	       return;
87 
88 	spin_lock(&sbi->work_lock);
89 	if (!sbi->work_queued) {
90 	       delay = msecs_to_jiffies(dirty_writeback_interval * 10);
91 	       queue_delayed_work(system_dfl_long_wq, &sbi->sb_work, delay);
92 	       sbi->work_queued = 1;
93 	}
94 	spin_unlock(&sbi->work_lock);
95 }
96 
97 static struct kmem_cache * affs_inode_cachep;
98 
99 static struct inode *affs_alloc_inode(struct super_block *sb)
100 {
101 	struct affs_inode_info *i;
102 
103 	i = alloc_inode_sb(sb, affs_inode_cachep, GFP_KERNEL);
104 	if (!i)
105 		return NULL;
106 
107 	inode_set_iversion(&i->vfs_inode, 1);
108 	i->i_lc = NULL;
109 	i->i_ext_bh = NULL;
110 	i->i_pa_cnt = 0;
111 
112 	return &i->vfs_inode;
113 }
114 
115 static void affs_free_inode(struct inode *inode)
116 {
117 	kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
118 }
119 
120 static void init_once(void *foo)
121 {
122 	struct affs_inode_info *ei = (struct affs_inode_info *) foo;
123 
124 	mutex_init(&ei->i_link_lock);
125 	mutex_init(&ei->i_ext_lock);
126 	inode_init_once(&ei->vfs_inode);
127 }
128 
129 static int __init init_inodecache(void)
130 {
131 	affs_inode_cachep = kmem_cache_create("affs_inode_cache",
132 					     sizeof(struct affs_inode_info),
133 					     0, (SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT),
134 					     init_once);
135 	if (affs_inode_cachep == NULL)
136 		return -ENOMEM;
137 	return 0;
138 }
139 
140 static void destroy_inodecache(void)
141 {
142 	/*
143 	 * Make sure all delayed rcu free inodes are flushed before we
144 	 * destroy cache.
145 	 */
146 	rcu_barrier();
147 	kmem_cache_destroy(affs_inode_cachep);
148 }
149 
150 static const struct super_operations affs_sops = {
151 	.alloc_inode	= affs_alloc_inode,
152 	.free_inode	= affs_free_inode,
153 	.write_inode	= affs_write_inode,
154 	.evict_inode	= affs_evict_inode,
155 	.put_super	= affs_put_super,
156 	.sync_fs	= affs_sync_fs,
157 	.statfs		= affs_statfs,
158 	.show_options	= affs_show_options,
159 };
160 
161 enum {
162 	Opt_bs, Opt_mode, Opt_mufs, Opt_notruncate, Opt_prefix, Opt_protect,
163 	Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
164 	Opt_verbose, Opt_volume, Opt_ignore,
165 };
166 
167 struct affs_context {
168 	kuid_t		uid;		/* uid to override */
169 	kgid_t		gid;		/* gid to override */
170 	unsigned int	mode;		/* mode to override */
171 	unsigned int	reserved;	/* Number of reserved blocks */
172 	int		root_block;	/* FFS root block number */
173 	int		blocksize;	/* Initial device blksize */
174 	char		*prefix;	/* Prefix for volumes and assigns */
175 	char		volume[32];	/* Vol. prefix for absolute symlinks */
176 	unsigned long	mount_flags;	/* Options */
177 };
178 
179 static const struct fs_parameter_spec affs_param_spec[] = {
180 	fsparam_u32	("bs",		Opt_bs),
181 	fsparam_u32oct	("mode",	Opt_mode),
182 	fsparam_flag	("mufs",	Opt_mufs),
183 	fsparam_flag	("nofilenametruncate",	Opt_notruncate),
184 	fsparam_string	("prefix",	Opt_prefix),
185 	fsparam_flag	("protect",	Opt_protect),
186 	fsparam_u32	("reserved",	Opt_reserved),
187 	fsparam_u32	("root",	Opt_root),
188 	fsparam_gid	("setgid",	Opt_setgid),
189 	fsparam_uid	("setuid",	Opt_setuid),
190 	fsparam_flag	("verbose",	Opt_verbose),
191 	fsparam_string	("volume",	Opt_volume),
192 	fsparam_flag	("grpquota",	Opt_ignore),
193 	fsparam_flag	("noquota",	Opt_ignore),
194 	fsparam_flag	("quota",	Opt_ignore),
195 	fsparam_flag	("usrquota",	Opt_ignore),
196 	{},
197 };
198 
199 static int affs_parse_param(struct fs_context *fc, struct fs_parameter *param)
200 {
201 	struct affs_context *ctx = fc->fs_private;
202 	struct fs_parse_result result;
203 	int n;
204 	int opt;
205 
206 	opt = fs_parse(fc, affs_param_spec, param, &result);
207 	if (opt < 0)
208 		return opt;
209 
210 	switch (opt) {
211 	case Opt_bs:
212 		n = result.uint_32;
213 		if (n != 512 && n != 1024 && n != 2048
214 		    && n != 4096) {
215 			pr_warn("Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
216 			return -EINVAL;
217 		}
218 		ctx->blocksize = n;
219 		break;
220 	case Opt_mode:
221 		ctx->mode = result.uint_32 & 0777;
222 		affs_set_opt(ctx->mount_flags, SF_SETMODE);
223 		break;
224 	case Opt_mufs:
225 		affs_set_opt(ctx->mount_flags, SF_MUFS);
226 		break;
227 	case Opt_notruncate:
228 		affs_set_opt(ctx->mount_flags, SF_NO_TRUNCATE);
229 		break;
230 	case Opt_prefix:
231 		kfree(ctx->prefix);
232 		ctx->prefix = param->string;
233 		param->string = NULL;
234 		affs_set_opt(ctx->mount_flags, SF_PREFIX);
235 		break;
236 	case Opt_protect:
237 		affs_set_opt(ctx->mount_flags, SF_IMMUTABLE);
238 		break;
239 	case Opt_reserved:
240 		ctx->reserved = result.uint_32;
241 		break;
242 	case Opt_root:
243 		ctx->root_block = result.uint_32;
244 		break;
245 	case Opt_setgid:
246 		ctx->gid = result.gid;
247 		affs_set_opt(ctx->mount_flags, SF_SETGID);
248 		break;
249 	case Opt_setuid:
250 		ctx->uid = result.uid;
251 		affs_set_opt(ctx->mount_flags, SF_SETUID);
252 		break;
253 	case Opt_verbose:
254 		affs_set_opt(ctx->mount_flags, SF_VERBOSE);
255 		break;
256 	case Opt_volume:
257 		strscpy(ctx->volume, param->string, 32);
258 		break;
259 	case Opt_ignore:
260 		/* Silently ignore the quota options */
261 		break;
262 	default:
263 		return -EINVAL;
264 	}
265 	return 0;
266 }
267 
268 static int affs_show_options(struct seq_file *m, struct dentry *root)
269 {
270 	struct super_block *sb = root->d_sb;
271 	struct affs_sb_info *sbi = AFFS_SB(sb);
272 
273 	if (sb->s_blocksize)
274 		seq_printf(m, ",bs=%lu", sb->s_blocksize);
275 	if (affs_test_opt(sbi->s_flags, SF_SETMODE))
276 		seq_printf(m, ",mode=%o", sbi->s_mode);
277 	if (affs_test_opt(sbi->s_flags, SF_MUFS))
278 		seq_puts(m, ",mufs");
279 	if (affs_test_opt(sbi->s_flags, SF_NO_TRUNCATE))
280 		seq_puts(m, ",nofilenametruncate");
281 	if (affs_test_opt(sbi->s_flags, SF_PREFIX))
282 		seq_printf(m, ",prefix=%s", sbi->s_prefix);
283 	if (affs_test_opt(sbi->s_flags, SF_IMMUTABLE))
284 		seq_puts(m, ",protect");
285 	if (sbi->s_reserved != 2)
286 		seq_printf(m, ",reserved=%u", sbi->s_reserved);
287 	if (sbi->s_root_block != (sbi->s_reserved + sbi->s_partition_size - 1) / 2)
288 		seq_printf(m, ",root=%u", sbi->s_root_block);
289 	if (affs_test_opt(sbi->s_flags, SF_SETGID))
290 		seq_printf(m, ",setgid=%u",
291 			   from_kgid_munged(&init_user_ns, sbi->s_gid));
292 	if (affs_test_opt(sbi->s_flags, SF_SETUID))
293 		seq_printf(m, ",setuid=%u",
294 			   from_kuid_munged(&init_user_ns, sbi->s_uid));
295 	if (affs_test_opt(sbi->s_flags, SF_VERBOSE))
296 		seq_puts(m, ",verbose");
297 	if (sbi->s_volume[0])
298 		seq_printf(m, ",volume=%s", sbi->s_volume);
299 	return 0;
300 }
301 
302 /* This function definitely needs to be split up. Some fine day I'll
303  * hopefully have the guts to do so. Until then: sorry for the mess.
304  */
305 
306 static int affs_fill_super(struct super_block *sb, struct fs_context *fc)
307 {
308 	struct affs_sb_info	*sbi;
309 	struct affs_context	*ctx = fc->fs_private;
310 	struct buffer_head	*root_bh = NULL;
311 	struct buffer_head	*boot_bh;
312 	struct inode		*root_inode = NULL;
313 	int			 silent = fc->sb_flags & SB_SILENT;
314 	int			 size, blocksize;
315 	u32			 chksum;
316 	int			 num_bm;
317 	int			 i, j;
318 	int			 tmp_flags;	/* fix remount prototype... */
319 	u8			 sig[4];
320 	int			 ret;
321 
322 	sb->s_magic             = AFFS_SUPER_MAGIC;
323 	sb->s_op                = &affs_sops;
324 	sb->s_flags |= SB_NODIRATIME;
325 
326 	sb->s_time_gran = NSEC_PER_SEC;
327 	sb->s_time_min = sys_tz.tz_minuteswest * 60 + AFFS_EPOCH_DELTA;
328 	sb->s_time_max = 86400LL * U32_MAX + 86400 + sb->s_time_min;
329 
330 	sbi = kzalloc_obj(struct affs_sb_info);
331 	if (!sbi)
332 		return -ENOMEM;
333 
334 	sb->s_fs_info = sbi;
335 	sbi->sb = sb;
336 	mutex_init(&sbi->s_bmlock);
337 	spin_lock_init(&sbi->symlink_lock);
338 	spin_lock_init(&sbi->work_lock);
339 	INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);
340 
341 	sbi->s_flags	= ctx->mount_flags;
342 	sbi->s_mode	= ctx->mode;
343 	sbi->s_uid	= ctx->uid;
344 	sbi->s_gid	= ctx->gid;
345 	sbi->s_reserved	= ctx->reserved;
346 	sbi->s_prefix	= ctx->prefix;
347 	ctx->prefix	= NULL;
348 	memcpy(sbi->s_volume, ctx->volume, 32);
349 
350 	/* N.B. after this point s_prefix must be released */
351 
352 	/* Get the size of the device in 512-byte blocks.
353 	 * If we later see that the partition uses bigger
354 	 * blocks, we will have to change it.
355 	 */
356 
357 	size = bdev_nr_sectors(sb->s_bdev);
358 	pr_debug("initial blocksize=%d, #blocks=%d\n", 512, size);
359 
360 	if (!sb_set_blocksize(sb, PAGE_SIZE))
361 		return -EINVAL;
362 	/* Try to find root block. Its location depends on the block size. */
363 
364 	i = bdev_logical_block_size(sb->s_bdev);
365 	j = PAGE_SIZE;
366 	blocksize = ctx->blocksize;
367 	if (blocksize > 0) {
368 		i = j = blocksize;
369 		size = size / (blocksize / 512);
370 	}
371 
372 	for (blocksize = i; blocksize <= j; blocksize <<= 1, size >>= 1) {
373 		sbi->s_root_block = ctx->root_block;
374 		if (ctx->root_block < 0)
375 			sbi->s_root_block = (ctx->reserved + size - 1) / 2;
376 		pr_debug("setting blocksize to %d\n", blocksize);
377 		if (!sb_set_blocksize(sb, blocksize))
378 			return -EINVAL;
379 		sbi->s_partition_size = size;
380 
381 		/* The root block location that was calculated above is not
382 		 * correct if the partition size is an odd number of 512-
383 		 * byte blocks, which will be rounded down to a number of
384 		 * 1024-byte blocks, and if there were an even number of
385 		 * reserved blocks. Ideally, all partition checkers should
386 		 * report the real number of blocks of the real blocksize,
387 		 * but since this just cannot be done, we have to try to
388 		 * find the root block anyways. In the above case, it is one
389 		 * block behind the calculated one. So we check this one, too.
390 		 */
391 		for (num_bm = 0; num_bm < 2; num_bm++) {
392 			pr_debug("Dev %s, trying root=%u, bs=%d, "
393 				"size=%d, reserved=%d\n",
394 				sb->s_id,
395 				sbi->s_root_block + num_bm,
396 				ctx->blocksize, size, ctx->reserved);
397 			root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
398 			if (!root_bh)
399 				continue;
400 			if (!affs_checksum_block(sb, root_bh) &&
401 			    be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
402 			    be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
403 				sbi->s_hashsize    = blocksize / 4 - 56;
404 				sbi->s_root_block += num_bm;
405 				goto got_root;
406 			}
407 			affs_brelse(root_bh);
408 			root_bh = NULL;
409 		}
410 	}
411 	if (!silent)
412 		pr_err("No valid root block on device %s\n", sb->s_id);
413 	return -EINVAL;
414 
415 	/* N.B. after this point bh must be released */
416 got_root:
417 	/* Keep super block in cache */
418 	sbi->s_root_bh = root_bh;
419 	ctx->root_block = sbi->s_root_block;
420 
421 	/* Find out which kind of FS we have */
422 	boot_bh = sb_bread(sb, 0);
423 	if (!boot_bh) {
424 		pr_err("Cannot read boot block\n");
425 		return -EINVAL;
426 	}
427 	memcpy(sig, boot_bh->b_data, 4);
428 	brelse(boot_bh);
429 	chksum = be32_to_cpu(*(__be32 *)sig);
430 
431 	/* Dircache filesystems are compatible with non-dircache ones
432 	 * when reading. As long as they aren't supported, writing is
433 	 * not recommended.
434 	 */
435 	if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
436 	     || chksum == MUFS_DCOFS) && !sb_rdonly(sb)) {
437 		pr_notice("Dircache FS - mounting %s read only\n", sb->s_id);
438 		sb->s_flags |= SB_RDONLY;
439 	}
440 	switch (chksum) {
441 	case MUFS_FS:
442 	case MUFS_INTLFFS:
443 	case MUFS_DCFFS:
444 		affs_set_opt(sbi->s_flags, SF_MUFS);
445 		fallthrough;
446 	case FS_INTLFFS:
447 	case FS_DCFFS:
448 		affs_set_opt(sbi->s_flags, SF_INTL);
449 		break;
450 	case MUFS_FFS:
451 		affs_set_opt(sbi->s_flags, SF_MUFS);
452 		break;
453 	case FS_FFS:
454 		break;
455 	case MUFS_OFS:
456 		affs_set_opt(sbi->s_flags, SF_MUFS);
457 		fallthrough;
458 	case FS_OFS:
459 		affs_set_opt(sbi->s_flags, SF_OFS);
460 		sb->s_flags |= SB_NOEXEC;
461 		break;
462 	case MUFS_DCOFS:
463 	case MUFS_INTLOFS:
464 		affs_set_opt(sbi->s_flags, SF_MUFS);
465 		fallthrough;
466 	case FS_DCOFS:
467 	case FS_INTLOFS:
468 		affs_set_opt(sbi->s_flags, SF_INTL);
469 		affs_set_opt(sbi->s_flags, SF_OFS);
470 		sb->s_flags |= SB_NOEXEC;
471 		break;
472 	default:
473 		pr_err("Unknown filesystem on device %s: %08X\n",
474 		       sb->s_id, chksum);
475 		return -EINVAL;
476 	}
477 
478 	if (affs_test_opt(ctx->mount_flags, SF_VERBOSE)) {
479 		u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
480 		pr_notice("Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
481 			len > 31 ? 31 : len,
482 			AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
483 			sig, sig[3] + '0', blocksize);
484 	}
485 
486 	sb->s_flags |= SB_NODEV | SB_NOSUID;
487 
488 	sbi->s_data_blksize = sb->s_blocksize;
489 	if (affs_test_opt(sbi->s_flags, SF_OFS))
490 		sbi->s_data_blksize -= 24;
491 
492 	tmp_flags = sb->s_flags;
493 	ret = affs_init_bitmap(sb, &tmp_flags);
494 	if (ret)
495 		return ret;
496 	sb->s_flags = tmp_flags;
497 
498 	/* set up enough so that it can read an inode */
499 
500 	root_inode = affs_iget(sb, ctx->root_block);
501 	if (IS_ERR(root_inode))
502 		return PTR_ERR(root_inode);
503 
504 	if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL))
505 		set_default_d_op(sb, &affs_intl_dentry_operations);
506 	else
507 		set_default_d_op(sb, &affs_dentry_operations);
508 
509 	sb->s_root = d_make_root(root_inode);
510 	if (!sb->s_root) {
511 		pr_err("AFFS: Get root inode failed\n");
512 		return -ENOMEM;
513 	}
514 
515 	sb->s_export_op = &affs_export_ops;
516 	pr_debug("s_flags=%lX\n", sb->s_flags);
517 	return 0;
518 }
519 
520 static int affs_reconfigure(struct fs_context *fc)
521 {
522 	struct super_block	*sb = fc->root->d_sb;
523 	struct affs_context	*ctx = fc->fs_private;
524 	struct affs_sb_info	*sbi = AFFS_SB(sb);
525 	int			 res = 0;
526 
527 	sync_filesystem(sb);
528 	fc->sb_flags |= SB_NODIRATIME;
529 
530 	flush_delayed_work(&sbi->sb_work);
531 
532 	/*
533 	 * NB: Historically, only mount_flags, mode, uid, gic, prefix,
534 	 * and volume are accepted during remount.
535 	 */
536 	sbi->s_flags = ctx->mount_flags;
537 	sbi->s_mode  = ctx->mode;
538 	sbi->s_uid   = ctx->uid;
539 	sbi->s_gid   = ctx->gid;
540 	/* protect against readers */
541 	spin_lock(&sbi->symlink_lock);
542 	if (ctx->prefix) {
543 		kfree(sbi->s_prefix);
544 		sbi->s_prefix = ctx->prefix;
545 		ctx->prefix = NULL;
546 	}
547 	memcpy(sbi->s_volume, ctx->volume, 32);
548 	spin_unlock(&sbi->symlink_lock);
549 
550 	if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
551 		return 0;
552 
553 	if (fc->sb_flags & SB_RDONLY)
554 		affs_free_bitmap(sb);
555 	else
556 		res = affs_init_bitmap(sb, &fc->sb_flags);
557 
558 	return res;
559 }
560 
561 static int
562 affs_statfs(struct dentry *dentry, struct kstatfs *buf)
563 {
564 	struct super_block *sb = dentry->d_sb;
565 	int		 free;
566 	u64		 id = huge_encode_dev(sb->s_bdev->bd_dev);
567 
568 	pr_debug("%s() partsize=%d, reserved=%d\n",
569 		 __func__, AFFS_SB(sb)->s_partition_size,
570 		 AFFS_SB(sb)->s_reserved);
571 
572 	free          = affs_count_free_blocks(sb);
573 	buf->f_type    = AFFS_SUPER_MAGIC;
574 	buf->f_bsize   = sb->s_blocksize;
575 	buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
576 	buf->f_bfree   = free;
577 	buf->f_bavail  = free;
578 	buf->f_fsid    = u64_to_fsid(id);
579 	buf->f_namelen = AFFSNAMEMAX;
580 	return 0;
581 }
582 
583 static int affs_get_tree(struct fs_context *fc)
584 {
585 	return get_tree_bdev(fc, affs_fill_super);
586 }
587 
588 static void affs_kill_sb(struct super_block *sb)
589 {
590 	struct affs_sb_info *sbi = AFFS_SB(sb);
591 	kill_block_super(sb);
592 	if (sbi) {
593 		affs_free_bitmap(sb);
594 		affs_brelse(sbi->s_root_bh);
595 		kfree(sbi->s_prefix);
596 		mutex_destroy(&sbi->s_bmlock);
597 		kfree_rcu(sbi, rcu);
598 	}
599 }
600 
601 static void affs_free_fc(struct fs_context *fc)
602 {
603 	struct affs_context *ctx = fc->fs_private;
604 
605 	kfree(ctx->prefix);
606 	kfree(ctx);
607 }
608 
609 static const struct fs_context_operations affs_context_ops = {
610 	.parse_param	= affs_parse_param,
611 	.get_tree	= affs_get_tree,
612 	.reconfigure	= affs_reconfigure,
613 	.free		= affs_free_fc,
614 };
615 
616 static int affs_init_fs_context(struct fs_context *fc)
617 {
618 	struct affs_context *ctx;
619 
620 	ctx = kzalloc_obj(struct affs_context);
621 	if (!ctx)
622 		return -ENOMEM;
623 
624 	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
625 		struct super_block *sb = fc->root->d_sb;
626 		struct affs_sb_info *sbi = AFFS_SB(sb);
627 
628 		/*
629 		 * NB: historically, no options other than volume were
630 		 * preserved across a remount unless they were explicitly
631 		 * passed in.
632 		 */
633 		memcpy(ctx->volume, sbi->s_volume, 32);
634 	} else {
635 		ctx->uid	= current_uid();
636 		ctx->gid	= current_gid();
637 		ctx->reserved	= 2;
638 		ctx->root_block	= -1;
639 		ctx->blocksize	= -1;
640 		ctx->volume[0]	= ':';
641 	}
642 
643 	fc->ops = &affs_context_ops;
644 	fc->fs_private = ctx;
645 
646 	return 0;
647 }
648 
649 static struct file_system_type affs_fs_type = {
650 	.owner		= THIS_MODULE,
651 	.name		= "affs",
652 	.kill_sb	= affs_kill_sb,
653 	.fs_flags	= FS_REQUIRES_DEV,
654 	.init_fs_context = affs_init_fs_context,
655 	.parameters	= affs_param_spec,
656 };
657 MODULE_ALIAS_FS("affs");
658 
659 static int __init init_affs_fs(void)
660 {
661 	int err = init_inodecache();
662 	if (err)
663 		goto out1;
664 	err = register_filesystem(&affs_fs_type);
665 	if (err)
666 		goto out;
667 	return 0;
668 out:
669 	destroy_inodecache();
670 out1:
671 	return err;
672 }
673 
674 static void __exit exit_affs_fs(void)
675 {
676 	unregister_filesystem(&affs_fs_type);
677 	destroy_inodecache();
678 }
679 
680 MODULE_DESCRIPTION("Amiga filesystem support for Linux");
681 MODULE_LICENSE("GPL");
682 
683 module_init(init_affs_fs)
684 module_exit(exit_affs_fs)
685