xref: /linux/fs/bfs/inode.c (revision db10cb9b) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *	fs/bfs/inode.c
4  *	BFS superblock and inode operations.
5  *	Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
6  *	From fs/minix, Copyright (C) 1991, 1992 Linus Torvalds.
7  *	Made endianness-clean by Andrew Stribblehill <ads@wompom.org>, 2005.
8  */
9 
10 #include <linux/module.h>
11 #include <linux/mm.h>
12 #include <linux/slab.h>
13 #include <linux/init.h>
14 #include <linux/fs.h>
15 #include <linux/buffer_head.h>
16 #include <linux/vfs.h>
17 #include <linux/writeback.h>
18 #include <linux/uio.h>
19 #include <linux/uaccess.h>
20 #include "bfs.h"
21 
22 MODULE_AUTHOR("Tigran Aivazian <aivazian.tigran@gmail.com>");
23 MODULE_DESCRIPTION("SCO UnixWare BFS filesystem for Linux");
24 MODULE_LICENSE("GPL");
25 
26 #undef DEBUG
27 
28 #ifdef DEBUG
29 #define dprintf(x...)	printf(x)
30 #else
31 #define dprintf(x...)
32 #endif
33 
34 struct inode *bfs_iget(struct super_block *sb, unsigned long ino)
35 {
36 	struct bfs_inode *di;
37 	struct inode *inode;
38 	struct buffer_head *bh;
39 	int block, off;
40 
41 	inode = iget_locked(sb, ino);
42 	if (!inode)
43 		return ERR_PTR(-ENOMEM);
44 	if (!(inode->i_state & I_NEW))
45 		return inode;
46 
47 	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
48 		printf("Bad inode number %s:%08lx\n", inode->i_sb->s_id, ino);
49 		goto error;
50 	}
51 
52 	block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
53 	bh = sb_bread(inode->i_sb, block);
54 	if (!bh) {
55 		printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id,
56 									ino);
57 		goto error;
58 	}
59 
60 	off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
61 	di = (struct bfs_inode *)bh->b_data + off;
62 
63 	inode->i_mode = 0x0000FFFF & le32_to_cpu(di->i_mode);
64 	if (le32_to_cpu(di->i_vtype) == BFS_VDIR) {
65 		inode->i_mode |= S_IFDIR;
66 		inode->i_op = &bfs_dir_inops;
67 		inode->i_fop = &bfs_dir_operations;
68 	} else if (le32_to_cpu(di->i_vtype) == BFS_VREG) {
69 		inode->i_mode |= S_IFREG;
70 		inode->i_op = &bfs_file_inops;
71 		inode->i_fop = &bfs_file_operations;
72 		inode->i_mapping->a_ops = &bfs_aops;
73 	}
74 
75 	BFS_I(inode)->i_sblock =  le32_to_cpu(di->i_sblock);
76 	BFS_I(inode)->i_eblock =  le32_to_cpu(di->i_eblock);
77 	BFS_I(inode)->i_dsk_ino = le16_to_cpu(di->i_ino);
78 	i_uid_write(inode, le32_to_cpu(di->i_uid));
79 	i_gid_write(inode,  le32_to_cpu(di->i_gid));
80 	set_nlink(inode, le32_to_cpu(di->i_nlink));
81 	inode->i_size = BFS_FILESIZE(di);
82 	inode->i_blocks = BFS_FILEBLOCKS(di);
83 	inode->i_atime.tv_sec =  le32_to_cpu(di->i_atime);
84 	inode->i_mtime.tv_sec =  le32_to_cpu(di->i_mtime);
85 	inode_set_ctime(inode, le32_to_cpu(di->i_ctime), 0);
86 	inode->i_atime.tv_nsec = 0;
87 	inode->i_mtime.tv_nsec = 0;
88 
89 	brelse(bh);
90 	unlock_new_inode(inode);
91 	return inode;
92 
93 error:
94 	iget_failed(inode);
95 	return ERR_PTR(-EIO);
96 }
97 
98 static struct bfs_inode *find_inode(struct super_block *sb, u16 ino, struct buffer_head **p)
99 {
100 	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(sb)->si_lasti)) {
101 		printf("Bad inode number %s:%08x\n", sb->s_id, ino);
102 		return ERR_PTR(-EIO);
103 	}
104 
105 	ino -= BFS_ROOT_INO;
106 
107 	*p = sb_bread(sb, 1 + ino / BFS_INODES_PER_BLOCK);
108 	if (!*p) {
109 		printf("Unable to read inode %s:%08x\n", sb->s_id, ino);
110 		return ERR_PTR(-EIO);
111 	}
112 
113 	return (struct bfs_inode *)(*p)->b_data +  ino % BFS_INODES_PER_BLOCK;
114 }
115 
116 static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
117 {
118 	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
119 	unsigned int ino = (u16)inode->i_ino;
120 	unsigned long i_sblock;
121 	struct bfs_inode *di;
122 	struct buffer_head *bh;
123 	int err = 0;
124 
125 	dprintf("ino=%08x\n", ino);
126 
127 	di = find_inode(inode->i_sb, ino, &bh);
128 	if (IS_ERR(di))
129 		return PTR_ERR(di);
130 
131 	mutex_lock(&info->bfs_lock);
132 
133 	if (ino == BFS_ROOT_INO)
134 		di->i_vtype = cpu_to_le32(BFS_VDIR);
135 	else
136 		di->i_vtype = cpu_to_le32(BFS_VREG);
137 
138 	di->i_ino = cpu_to_le16(ino);
139 	di->i_mode = cpu_to_le32(inode->i_mode);
140 	di->i_uid = cpu_to_le32(i_uid_read(inode));
141 	di->i_gid = cpu_to_le32(i_gid_read(inode));
142 	di->i_nlink = cpu_to_le32(inode->i_nlink);
143 	di->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
144 	di->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
145 	di->i_ctime = cpu_to_le32(inode_get_ctime(inode).tv_sec);
146 	i_sblock = BFS_I(inode)->i_sblock;
147 	di->i_sblock = cpu_to_le32(i_sblock);
148 	di->i_eblock = cpu_to_le32(BFS_I(inode)->i_eblock);
149 	di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);
150 
151 	mark_buffer_dirty(bh);
152 	if (wbc->sync_mode == WB_SYNC_ALL) {
153 		sync_dirty_buffer(bh);
154 		if (buffer_req(bh) && !buffer_uptodate(bh))
155 			err = -EIO;
156 	}
157 	brelse(bh);
158 	mutex_unlock(&info->bfs_lock);
159 	return err;
160 }
161 
162 static void bfs_evict_inode(struct inode *inode)
163 {
164 	unsigned long ino = inode->i_ino;
165 	struct bfs_inode *di;
166 	struct buffer_head *bh;
167 	struct super_block *s = inode->i_sb;
168 	struct bfs_sb_info *info = BFS_SB(s);
169 	struct bfs_inode_info *bi = BFS_I(inode);
170 
171 	dprintf("ino=%08lx\n", ino);
172 
173 	truncate_inode_pages_final(&inode->i_data);
174 	invalidate_inode_buffers(inode);
175 	clear_inode(inode);
176 
177 	if (inode->i_nlink)
178 		return;
179 
180 	di = find_inode(s, inode->i_ino, &bh);
181 	if (IS_ERR(di))
182 		return;
183 
184 	mutex_lock(&info->bfs_lock);
185 	/* clear on-disk inode */
186 	memset(di, 0, sizeof(struct bfs_inode));
187 	mark_buffer_dirty(bh);
188 	brelse(bh);
189 
190 	if (bi->i_dsk_ino) {
191 		if (bi->i_sblock)
192 			info->si_freeb += bi->i_eblock + 1 - bi->i_sblock;
193 		info->si_freei++;
194 		clear_bit(ino, info->si_imap);
195 		bfs_dump_imap("evict_inode", s);
196 	}
197 
198 	/*
199 	 * If this was the last file, make the previous block
200 	 * "last block of the last file" even if there is no
201 	 * real file there, saves us 1 gap.
202 	 */
203 	if (info->si_lf_eblk == bi->i_eblock)
204 		info->si_lf_eblk = bi->i_sblock - 1;
205 	mutex_unlock(&info->bfs_lock);
206 }
207 
208 static void bfs_put_super(struct super_block *s)
209 {
210 	struct bfs_sb_info *info = BFS_SB(s);
211 
212 	if (!info)
213 		return;
214 
215 	mutex_destroy(&info->bfs_lock);
216 	kfree(info);
217 	s->s_fs_info = NULL;
218 }
219 
220 static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)
221 {
222 	struct super_block *s = dentry->d_sb;
223 	struct bfs_sb_info *info = BFS_SB(s);
224 	u64 id = huge_encode_dev(s->s_bdev->bd_dev);
225 	buf->f_type = BFS_MAGIC;
226 	buf->f_bsize = s->s_blocksize;
227 	buf->f_blocks = info->si_blocks;
228 	buf->f_bfree = buf->f_bavail = info->si_freeb;
229 	buf->f_files = info->si_lasti + 1 - BFS_ROOT_INO;
230 	buf->f_ffree = info->si_freei;
231 	buf->f_fsid = u64_to_fsid(id);
232 	buf->f_namelen = BFS_NAMELEN;
233 	return 0;
234 }
235 
236 static struct kmem_cache *bfs_inode_cachep;
237 
238 static struct inode *bfs_alloc_inode(struct super_block *sb)
239 {
240 	struct bfs_inode_info *bi;
241 	bi = alloc_inode_sb(sb, bfs_inode_cachep, GFP_KERNEL);
242 	if (!bi)
243 		return NULL;
244 	return &bi->vfs_inode;
245 }
246 
247 static void bfs_free_inode(struct inode *inode)
248 {
249 	kmem_cache_free(bfs_inode_cachep, BFS_I(inode));
250 }
251 
252 static void init_once(void *foo)
253 {
254 	struct bfs_inode_info *bi = foo;
255 
256 	inode_init_once(&bi->vfs_inode);
257 }
258 
259 static int __init init_inodecache(void)
260 {
261 	bfs_inode_cachep = kmem_cache_create("bfs_inode_cache",
262 					     sizeof(struct bfs_inode_info),
263 					     0, (SLAB_RECLAIM_ACCOUNT|
264 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
265 					     init_once);
266 	if (bfs_inode_cachep == NULL)
267 		return -ENOMEM;
268 	return 0;
269 }
270 
271 static void destroy_inodecache(void)
272 {
273 	/*
274 	 * Make sure all delayed rcu free inodes are flushed before we
275 	 * destroy cache.
276 	 */
277 	rcu_barrier();
278 	kmem_cache_destroy(bfs_inode_cachep);
279 }
280 
281 static const struct super_operations bfs_sops = {
282 	.alloc_inode	= bfs_alloc_inode,
283 	.free_inode	= bfs_free_inode,
284 	.write_inode	= bfs_write_inode,
285 	.evict_inode	= bfs_evict_inode,
286 	.put_super	= bfs_put_super,
287 	.statfs		= bfs_statfs,
288 };
289 
290 void bfs_dump_imap(const char *prefix, struct super_block *s)
291 {
292 #ifdef DEBUG
293 	int i;
294 	char *tmpbuf = (char *)get_zeroed_page(GFP_KERNEL);
295 
296 	if (!tmpbuf)
297 		return;
298 	for (i = BFS_SB(s)->si_lasti; i >= 0; i--) {
299 		if (i > PAGE_SIZE - 100) break;
300 		if (test_bit(i, BFS_SB(s)->si_imap))
301 			strcat(tmpbuf, "1");
302 		else
303 			strcat(tmpbuf, "0");
304 	}
305 	printf("%s: lasti=%08lx <%s>\n", prefix, BFS_SB(s)->si_lasti, tmpbuf);
306 	free_page((unsigned long)tmpbuf);
307 #endif
308 }
309 
310 static int bfs_fill_super(struct super_block *s, void *data, int silent)
311 {
312 	struct buffer_head *bh, *sbh;
313 	struct bfs_super_block *bfs_sb;
314 	struct inode *inode;
315 	unsigned i;
316 	struct bfs_sb_info *info;
317 	int ret = -EINVAL;
318 	unsigned long i_sblock, i_eblock, i_eoff, s_size;
319 
320 	info = kzalloc(sizeof(*info), GFP_KERNEL);
321 	if (!info)
322 		return -ENOMEM;
323 	mutex_init(&info->bfs_lock);
324 	s->s_fs_info = info;
325 	s->s_time_min = 0;
326 	s->s_time_max = U32_MAX;
327 
328 	sb_set_blocksize(s, BFS_BSIZE);
329 
330 	sbh = sb_bread(s, 0);
331 	if (!sbh)
332 		goto out;
333 	bfs_sb = (struct bfs_super_block *)sbh->b_data;
334 	if (le32_to_cpu(bfs_sb->s_magic) != BFS_MAGIC) {
335 		if (!silent)
336 			printf("No BFS filesystem on %s (magic=%08x)\n", s->s_id,  le32_to_cpu(bfs_sb->s_magic));
337 		goto out1;
338 	}
339 	if (BFS_UNCLEAN(bfs_sb, s) && !silent)
340 		printf("%s is unclean, continuing\n", s->s_id);
341 
342 	s->s_magic = BFS_MAGIC;
343 
344 	if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end) ||
345 	    le32_to_cpu(bfs_sb->s_start) < sizeof(struct bfs_super_block) + sizeof(struct bfs_dirent)) {
346 		printf("Superblock is corrupted on %s\n", s->s_id);
347 		goto out1;
348 	}
349 
350 	info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) / sizeof(struct bfs_inode) + BFS_ROOT_INO - 1;
351 	if (info->si_lasti == BFS_MAX_LASTI)
352 		printf("NOTE: filesystem %s was created with 512 inodes, the real maximum is 511, mounting anyway\n", s->s_id);
353 	else if (info->si_lasti > BFS_MAX_LASTI) {
354 		printf("Impossible last inode number %lu > %d on %s\n", info->si_lasti, BFS_MAX_LASTI, s->s_id);
355 		goto out1;
356 	}
357 	for (i = 0; i < BFS_ROOT_INO; i++)
358 		set_bit(i, info->si_imap);
359 
360 	s->s_op = &bfs_sops;
361 	inode = bfs_iget(s, BFS_ROOT_INO);
362 	if (IS_ERR(inode)) {
363 		ret = PTR_ERR(inode);
364 		goto out1;
365 	}
366 	s->s_root = d_make_root(inode);
367 	if (!s->s_root) {
368 		ret = -ENOMEM;
369 		goto out1;
370 	}
371 
372 	info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1) >> BFS_BSIZE_BITS;
373 	info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1 - le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS;
374 	info->si_freei = 0;
375 	info->si_lf_eblk = 0;
376 
377 	/* can we read the last block? */
378 	bh = sb_bread(s, info->si_blocks - 1);
379 	if (!bh) {
380 		printf("Last block not available on %s: %lu\n", s->s_id, info->si_blocks - 1);
381 		ret = -EIO;
382 		goto out2;
383 	}
384 	brelse(bh);
385 
386 	bh = NULL;
387 	for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
388 		struct bfs_inode *di;
389 		int block = (i - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
390 		int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
391 		unsigned long eblock;
392 
393 		if (!off) {
394 			brelse(bh);
395 			bh = sb_bread(s, block);
396 		}
397 
398 		if (!bh)
399 			continue;
400 
401 		di = (struct bfs_inode *)bh->b_data + off;
402 
403 		/* test if filesystem is not corrupted */
404 
405 		i_eoff = le32_to_cpu(di->i_eoffset);
406 		i_sblock = le32_to_cpu(di->i_sblock);
407 		i_eblock = le32_to_cpu(di->i_eblock);
408 		s_size = le32_to_cpu(bfs_sb->s_end);
409 
410 		if (i_sblock > info->si_blocks ||
411 			i_eblock > info->si_blocks ||
412 			i_sblock > i_eblock ||
413 			(i_eoff != le32_to_cpu(-1) && i_eoff > s_size) ||
414 			i_sblock * BFS_BSIZE > i_eoff) {
415 
416 			printf("Inode 0x%08x corrupted on %s\n", i, s->s_id);
417 
418 			brelse(bh);
419 			ret = -EIO;
420 			goto out2;
421 		}
422 
423 		if (!di->i_ino) {
424 			info->si_freei++;
425 			continue;
426 		}
427 		set_bit(i, info->si_imap);
428 		info->si_freeb -= BFS_FILEBLOCKS(di);
429 
430 		eblock =  le32_to_cpu(di->i_eblock);
431 		if (eblock > info->si_lf_eblk)
432 			info->si_lf_eblk = eblock;
433 	}
434 	brelse(bh);
435 	brelse(sbh);
436 	bfs_dump_imap("fill_super", s);
437 	return 0;
438 
439 out2:
440 	dput(s->s_root);
441 	s->s_root = NULL;
442 out1:
443 	brelse(sbh);
444 out:
445 	mutex_destroy(&info->bfs_lock);
446 	kfree(info);
447 	s->s_fs_info = NULL;
448 	return ret;
449 }
450 
451 static struct dentry *bfs_mount(struct file_system_type *fs_type,
452 	int flags, const char *dev_name, void *data)
453 {
454 	return mount_bdev(fs_type, flags, dev_name, data, bfs_fill_super);
455 }
456 
457 static struct file_system_type bfs_fs_type = {
458 	.owner		= THIS_MODULE,
459 	.name		= "bfs",
460 	.mount		= bfs_mount,
461 	.kill_sb	= kill_block_super,
462 	.fs_flags	= FS_REQUIRES_DEV,
463 };
464 MODULE_ALIAS_FS("bfs");
465 
466 static int __init init_bfs_fs(void)
467 {
468 	int err = init_inodecache();
469 	if (err)
470 		goto out1;
471 	err = register_filesystem(&bfs_fs_type);
472 	if (err)
473 		goto out;
474 	return 0;
475 out:
476 	destroy_inodecache();
477 out1:
478 	return err;
479 }
480 
481 static void __exit exit_bfs_fs(void)
482 {
483 	unregister_filesystem(&bfs_fs_type);
484 	destroy_inodecache();
485 }
486 
487 module_init(init_bfs_fs)
488 module_exit(exit_bfs_fs)
489