xref: /openbmc/linux/fs/bfs/inode.c (revision 2fa5ebe3) 
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->i_ctime.tv_sec =  le32_to_cpu(di->i_ctime);
86 	inode->i_atime.tv_nsec = 0;
87 	inode->i_mtime.tv_nsec = 0;
88 	inode->i_ctime.tv_nsec = 0;
89 
90 	brelse(bh);
91 	unlock_new_inode(inode);
92 	return inode;
93 
94 error:
95 	iget_failed(inode);
96 	return ERR_PTR(-EIO);
97 }
98 
99 static struct bfs_inode *find_inode(struct super_block *sb, u16 ino, struct buffer_head **p)
100 {
101 	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(sb)->si_lasti)) {
102 		printf("Bad inode number %s:%08x\n", sb->s_id, ino);
103 		return ERR_PTR(-EIO);
104 	}
105 
106 	ino -= BFS_ROOT_INO;
107 
108 	*p = sb_bread(sb, 1 + ino / BFS_INODES_PER_BLOCK);
109 	if (!*p) {
110 		printf("Unable to read inode %s:%08x\n", sb->s_id, ino);
111 		return ERR_PTR(-EIO);
112 	}
113 
114 	return (struct bfs_inode *)(*p)->b_data +  ino % BFS_INODES_PER_BLOCK;
115 }
116 
117 static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
118 {
119 	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
120 	unsigned int ino = (u16)inode->i_ino;
121 	unsigned long i_sblock;
122 	struct bfs_inode *di;
123 	struct buffer_head *bh;
124 	int err = 0;
125 
126 	dprintf("ino=%08x\n", ino);
127 
128 	di = find_inode(inode->i_sb, ino, &bh);
129 	if (IS_ERR(di))
130 		return PTR_ERR(di);
131 
132 	mutex_lock(&info->bfs_lock);
133 
134 	if (ino == BFS_ROOT_INO)
135 		di->i_vtype = cpu_to_le32(BFS_VDIR);
136 	else
137 		di->i_vtype = cpu_to_le32(BFS_VREG);
138 
139 	di->i_ino = cpu_to_le16(ino);
140 	di->i_mode = cpu_to_le32(inode->i_mode);
141 	di->i_uid = cpu_to_le32(i_uid_read(inode));
142 	di->i_gid = cpu_to_le32(i_gid_read(inode));
143 	di->i_nlink = cpu_to_le32(inode->i_nlink);
144 	di->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
145 	di->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
146 	di->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
147 	i_sblock = BFS_I(inode)->i_sblock;
148 	di->i_sblock = cpu_to_le32(i_sblock);
149 	di->i_eblock = cpu_to_le32(BFS_I(inode)->i_eblock);
150 	di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);
151 
152 	mark_buffer_dirty(bh);
153 	if (wbc->sync_mode == WB_SYNC_ALL) {
154 		sync_dirty_buffer(bh);
155 		if (buffer_req(bh) && !buffer_uptodate(bh))
156 			err = -EIO;
157 	}
158 	brelse(bh);
159 	mutex_unlock(&info->bfs_lock);
160 	return err;
161 }
162 
163 static void bfs_evict_inode(struct inode *inode)
164 {
165 	unsigned long ino = inode->i_ino;
166 	struct bfs_inode *di;
167 	struct buffer_head *bh;
168 	struct super_block *s = inode->i_sb;
169 	struct bfs_sb_info *info = BFS_SB(s);
170 	struct bfs_inode_info *bi = BFS_I(inode);
171 
172 	dprintf("ino=%08lx\n", ino);
173 
174 	truncate_inode_pages_final(&inode->i_data);
175 	invalidate_inode_buffers(inode);
176 	clear_inode(inode);
177 
178 	if (inode->i_nlink)
179 		return;
180 
181 	di = find_inode(s, inode->i_ino, &bh);
182 	if (IS_ERR(di))
183 		return;
184 
185 	mutex_lock(&info->bfs_lock);
186 	/* clear on-disk inode */
187 	memset(di, 0, sizeof(struct bfs_inode));
188 	mark_buffer_dirty(bh);
189 	brelse(bh);
190 
191 	if (bi->i_dsk_ino) {
192 		if (bi->i_sblock)
193 			info->si_freeb += bi->i_eblock + 1 - bi->i_sblock;
194 		info->si_freei++;
195 		clear_bit(ino, info->si_imap);
196 		bfs_dump_imap("evict_inode", s);
197 	}
198 
199 	/*
200 	 * If this was the last file, make the previous block
201 	 * "last block of the last file" even if there is no
202 	 * real file there, saves us 1 gap.
203 	 */
204 	if (info->si_lf_eblk == bi->i_eblock)
205 		info->si_lf_eblk = bi->i_sblock - 1;
206 	mutex_unlock(&info->bfs_lock);
207 }
208 
209 static void bfs_put_super(struct super_block *s)
210 {
211 	struct bfs_sb_info *info = BFS_SB(s);
212 
213 	if (!info)
214 		return;
215 
216 	mutex_destroy(&info->bfs_lock);
217 	kfree(info);
218 	s->s_fs_info = NULL;
219 }
220 
221 static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)
222 {
223 	struct super_block *s = dentry->d_sb;
224 	struct bfs_sb_info *info = BFS_SB(s);
225 	u64 id = huge_encode_dev(s->s_bdev->bd_dev);
226 	buf->f_type = BFS_MAGIC;
227 	buf->f_bsize = s->s_blocksize;
228 	buf->f_blocks = info->si_blocks;
229 	buf->f_bfree = buf->f_bavail = info->si_freeb;
230 	buf->f_files = info->si_lasti + 1 - BFS_ROOT_INO;
231 	buf->f_ffree = info->si_freei;
232 	buf->f_fsid = u64_to_fsid(id);
233 	buf->f_namelen = BFS_NAMELEN;
234 	return 0;
235 }
236 
237 static struct kmem_cache *bfs_inode_cachep;
238 
239 static struct inode *bfs_alloc_inode(struct super_block *sb)
240 {
241 	struct bfs_inode_info *bi;
242 	bi = alloc_inode_sb(sb, bfs_inode_cachep, GFP_KERNEL);
243 	if (!bi)
244 		return NULL;
245 	return &bi->vfs_inode;
246 }
247 
248 static void bfs_free_inode(struct inode *inode)
249 {
250 	kmem_cache_free(bfs_inode_cachep, BFS_I(inode));
251 }
252 
253 static void init_once(void *foo)
254 {
255 	struct bfs_inode_info *bi = foo;
256 
257 	inode_init_once(&bi->vfs_inode);
258 }
259 
260 static int __init init_inodecache(void)
261 {
262 	bfs_inode_cachep = kmem_cache_create("bfs_inode_cache",
263 					     sizeof(struct bfs_inode_info),
264 					     0, (SLAB_RECLAIM_ACCOUNT|
265 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
266 					     init_once);
267 	if (bfs_inode_cachep == NULL)
268 		return -ENOMEM;
269 	return 0;
270 }
271 
272 static void destroy_inodecache(void)
273 {
274 	/*
275 	 * Make sure all delayed rcu free inodes are flushed before we
276 	 * destroy cache.
277 	 */
278 	rcu_barrier();
279 	kmem_cache_destroy(bfs_inode_cachep);
280 }
281 
282 static const struct super_operations bfs_sops = {
283 	.alloc_inode	= bfs_alloc_inode,
284 	.free_inode	= bfs_free_inode,
285 	.write_inode	= bfs_write_inode,
286 	.evict_inode	= bfs_evict_inode,
287 	.put_super	= bfs_put_super,
288 	.statfs		= bfs_statfs,
289 };
290 
291 void bfs_dump_imap(const char *prefix, struct super_block *s)
292 {
293 #ifdef DEBUG
294 	int i;
295 	char *tmpbuf = (char *)get_zeroed_page(GFP_KERNEL);
296 
297 	if (!tmpbuf)
298 		return;
299 	for (i = BFS_SB(s)->si_lasti; i >= 0; i--) {
300 		if (i > PAGE_SIZE - 100) break;
301 		if (test_bit(i, BFS_SB(s)->si_imap))
302 			strcat(tmpbuf, "1");
303 		else
304 			strcat(tmpbuf, "0");
305 	}
306 	printf("%s: lasti=%08lx <%s>\n", prefix, BFS_SB(s)->si_lasti, tmpbuf);
307 	free_page((unsigned long)tmpbuf);
308 #endif
309 }
310 
311 static int bfs_fill_super(struct super_block *s, void *data, int silent)
312 {
313 	struct buffer_head *bh, *sbh;
314 	struct bfs_super_block *bfs_sb;
315 	struct inode *inode;
316 	unsigned i;
317 	struct bfs_sb_info *info;
318 	int ret = -EINVAL;
319 	unsigned long i_sblock, i_eblock, i_eoff, s_size;
320 
321 	info = kzalloc(sizeof(*info), GFP_KERNEL);
322 	if (!info)
323 		return -ENOMEM;
324 	mutex_init(&info->bfs_lock);
325 	s->s_fs_info = info;
326 	s->s_time_min = 0;
327 	s->s_time_max = U32_MAX;
328 
329 	sb_set_blocksize(s, BFS_BSIZE);
330 
331 	sbh = sb_bread(s, 0);
332 	if (!sbh)
333 		goto out;
334 	bfs_sb = (struct bfs_super_block *)sbh->b_data;
335 	if (le32_to_cpu(bfs_sb->s_magic) != BFS_MAGIC) {
336 		if (!silent)
337 			printf("No BFS filesystem on %s (magic=%08x)\n", s->s_id,  le32_to_cpu(bfs_sb->s_magic));
338 		goto out1;
339 	}
340 	if (BFS_UNCLEAN(bfs_sb, s) && !silent)
341 		printf("%s is unclean, continuing\n", s->s_id);
342 
343 	s->s_magic = BFS_MAGIC;
344 
345 	if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end) ||
346 	    le32_to_cpu(bfs_sb->s_start) < sizeof(struct bfs_super_block) + sizeof(struct bfs_dirent)) {
347 		printf("Superblock is corrupted on %s\n", s->s_id);
348 		goto out1;
349 	}
350 
351 	info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) / sizeof(struct bfs_inode) + BFS_ROOT_INO - 1;
352 	if (info->si_lasti == BFS_MAX_LASTI)
353 		printf("NOTE: filesystem %s was created with 512 inodes, the real maximum is 511, mounting anyway\n", s->s_id);
354 	else if (info->si_lasti > BFS_MAX_LASTI) {
355 		printf("Impossible last inode number %lu > %d on %s\n", info->si_lasti, BFS_MAX_LASTI, s->s_id);
356 		goto out1;
357 	}
358 	for (i = 0; i < BFS_ROOT_INO; i++)
359 		set_bit(i, info->si_imap);
360 
361 	s->s_op = &bfs_sops;
362 	inode = bfs_iget(s, BFS_ROOT_INO);
363 	if (IS_ERR(inode)) {
364 		ret = PTR_ERR(inode);
365 		goto out1;
366 	}
367 	s->s_root = d_make_root(inode);
368 	if (!s->s_root) {
369 		ret = -ENOMEM;
370 		goto out1;
371 	}
372 
373 	info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1) >> BFS_BSIZE_BITS;
374 	info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1 - le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS;
375 	info->si_freei = 0;
376 	info->si_lf_eblk = 0;
377 
378 	/* can we read the last block? */
379 	bh = sb_bread(s, info->si_blocks - 1);
380 	if (!bh) {
381 		printf("Last block not available on %s: %lu\n", s->s_id, info->si_blocks - 1);
382 		ret = -EIO;
383 		goto out2;
384 	}
385 	brelse(bh);
386 
387 	bh = NULL;
388 	for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
389 		struct bfs_inode *di;
390 		int block = (i - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
391 		int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
392 		unsigned long eblock;
393 
394 		if (!off) {
395 			brelse(bh);
396 			bh = sb_bread(s, block);
397 		}
398 
399 		if (!bh)
400 			continue;
401 
402 		di = (struct bfs_inode *)bh->b_data + off;
403 
404 		/* test if filesystem is not corrupted */
405 
406 		i_eoff = le32_to_cpu(di->i_eoffset);
407 		i_sblock = le32_to_cpu(di->i_sblock);
408 		i_eblock = le32_to_cpu(di->i_eblock);
409 		s_size = le32_to_cpu(bfs_sb->s_end);
410 
411 		if (i_sblock > info->si_blocks ||
412 			i_eblock > info->si_blocks ||
413 			i_sblock > i_eblock ||
414 			(i_eoff != le32_to_cpu(-1) && i_eoff > s_size) ||
415 			i_sblock * BFS_BSIZE > i_eoff) {
416 
417 			printf("Inode 0x%08x corrupted on %s\n", i, s->s_id);
418 
419 			brelse(bh);
420 			ret = -EIO;
421 			goto out2;
422 		}
423 
424 		if (!di->i_ino) {
425 			info->si_freei++;
426 			continue;
427 		}
428 		set_bit(i, info->si_imap);
429 		info->si_freeb -= BFS_FILEBLOCKS(di);
430 
431 		eblock =  le32_to_cpu(di->i_eblock);
432 		if (eblock > info->si_lf_eblk)
433 			info->si_lf_eblk = eblock;
434 	}
435 	brelse(bh);
436 	brelse(sbh);
437 	bfs_dump_imap("fill_super", s);
438 	return 0;
439 
440 out2:
441 	dput(s->s_root);
442 	s->s_root = NULL;
443 out1:
444 	brelse(sbh);
445 out:
446 	mutex_destroy(&info->bfs_lock);
447 	kfree(info);
448 	s->s_fs_info = NULL;
449 	return ret;
450 }
451 
452 static struct dentry *bfs_mount(struct file_system_type *fs_type,
453 	int flags, const char *dev_name, void *data)
454 {
455 	return mount_bdev(fs_type, flags, dev_name, data, bfs_fill_super);
456 }
457 
458 static struct file_system_type bfs_fs_type = {
459 	.owner		= THIS_MODULE,
460 	.name		= "bfs",
461 	.mount		= bfs_mount,
462 	.kill_sb	= kill_block_super,
463 	.fs_flags	= FS_REQUIRES_DEV,
464 };
465 MODULE_ALIAS_FS("bfs");
466 
467 static int __init init_bfs_fs(void)
468 {
469 	int err = init_inodecache();
470 	if (err)
471 		goto out1;
472 	err = register_filesystem(&bfs_fs_type);
473 	if (err)
474 		goto out;
475 	return 0;
476 out:
477 	destroy_inodecache();
478 out1:
479 	return err;
480 }
481 
482 static void __exit exit_bfs_fs(void)
483 {
484 	unregister_filesystem(&bfs_fs_type);
485 	destroy_inodecache();
486 }
487 
488 module_init(init_bfs_fs)
489 module_exit(exit_bfs_fs)
490