xref: /openbmc/linux/fs/hfs/inode.c (revision 4beec1d7)
1 /*
2  *  linux/fs/hfs/inode.c
3  *
4  * Copyright (C) 1995-1997  Paul H. Hargrove
5  * (C) 2003 Ardis Technologies <roman@ardistech.com>
6  * This file may be distributed under the terms of the GNU General Public License.
7  *
8  * This file contains inode-related functions which do not depend on
9  * which scheme is being used to represent forks.
10  *
11  * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
12  */
13 
14 #include <linux/pagemap.h>
15 #include <linux/mpage.h>
16 #include <linux/sched.h>
17 #include <linux/uio.h>
18 #include <linux/xattr.h>
19 
20 #include "hfs_fs.h"
21 #include "btree.h"
22 
23 static const struct file_operations hfs_file_operations;
24 static const struct inode_operations hfs_file_inode_operations;
25 
26 /*================ Variable-like macros ================*/
27 
28 #define HFS_VALID_MODE_BITS  (S_IFREG | S_IFDIR | S_IRWXUGO)
29 
30 static int hfs_writepage(struct page *page, struct writeback_control *wbc)
31 {
32 	return block_write_full_page(page, hfs_get_block, wbc);
33 }
34 
35 static int hfs_readpage(struct file *file, struct page *page)
36 {
37 	return block_read_full_page(page, hfs_get_block);
38 }
39 
40 static void hfs_write_failed(struct address_space *mapping, loff_t to)
41 {
42 	struct inode *inode = mapping->host;
43 
44 	if (to > inode->i_size) {
45 		truncate_pagecache(inode, inode->i_size);
46 		hfs_file_truncate(inode);
47 	}
48 }
49 
50 static int hfs_write_begin(struct file *file, struct address_space *mapping,
51 			loff_t pos, unsigned len, unsigned flags,
52 			struct page **pagep, void **fsdata)
53 {
54 	int ret;
55 
56 	*pagep = NULL;
57 	ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
58 				hfs_get_block,
59 				&HFS_I(mapping->host)->phys_size);
60 	if (unlikely(ret))
61 		hfs_write_failed(mapping, pos + len);
62 
63 	return ret;
64 }
65 
66 static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
67 {
68 	return generic_block_bmap(mapping, block, hfs_get_block);
69 }
70 
71 static int hfs_releasepage(struct page *page, gfp_t mask)
72 {
73 	struct inode *inode = page->mapping->host;
74 	struct super_block *sb = inode->i_sb;
75 	struct hfs_btree *tree;
76 	struct hfs_bnode *node;
77 	u32 nidx;
78 	int i, res = 1;
79 
80 	switch (inode->i_ino) {
81 	case HFS_EXT_CNID:
82 		tree = HFS_SB(sb)->ext_tree;
83 		break;
84 	case HFS_CAT_CNID:
85 		tree = HFS_SB(sb)->cat_tree;
86 		break;
87 	default:
88 		BUG();
89 		return 0;
90 	}
91 
92 	if (!tree)
93 		return 0;
94 
95 	if (tree->node_size >= PAGE_SIZE) {
96 		nidx = page->index >> (tree->node_size_shift - PAGE_SHIFT);
97 		spin_lock(&tree->hash_lock);
98 		node = hfs_bnode_findhash(tree, nidx);
99 		if (!node)
100 			;
101 		else if (atomic_read(&node->refcnt))
102 			res = 0;
103 		if (res && node) {
104 			hfs_bnode_unhash(node);
105 			hfs_bnode_free(node);
106 		}
107 		spin_unlock(&tree->hash_lock);
108 	} else {
109 		nidx = page->index << (PAGE_SHIFT - tree->node_size_shift);
110 		i = 1 << (PAGE_SHIFT - tree->node_size_shift);
111 		spin_lock(&tree->hash_lock);
112 		do {
113 			node = hfs_bnode_findhash(tree, nidx++);
114 			if (!node)
115 				continue;
116 			if (atomic_read(&node->refcnt)) {
117 				res = 0;
118 				break;
119 			}
120 			hfs_bnode_unhash(node);
121 			hfs_bnode_free(node);
122 		} while (--i && nidx < tree->node_count);
123 		spin_unlock(&tree->hash_lock);
124 	}
125 	return res ? try_to_free_buffers(page) : 0;
126 }
127 
128 static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
129 {
130 	struct file *file = iocb->ki_filp;
131 	struct address_space *mapping = file->f_mapping;
132 	struct inode *inode = mapping->host;
133 	size_t count = iov_iter_count(iter);
134 	ssize_t ret;
135 
136 	ret = blockdev_direct_IO(iocb, inode, iter, hfs_get_block);
137 
138 	/*
139 	 * In case of error extending write may have instantiated a few
140 	 * blocks outside i_size. Trim these off again.
141 	 */
142 	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
143 		loff_t isize = i_size_read(inode);
144 		loff_t end = iocb->ki_pos + count;
145 
146 		if (end > isize)
147 			hfs_write_failed(mapping, end);
148 	}
149 
150 	return ret;
151 }
152 
153 static int hfs_writepages(struct address_space *mapping,
154 			  struct writeback_control *wbc)
155 {
156 	return mpage_writepages(mapping, wbc, hfs_get_block);
157 }
158 
159 const struct address_space_operations hfs_btree_aops = {
160 	.readpage	= hfs_readpage,
161 	.writepage	= hfs_writepage,
162 	.write_begin	= hfs_write_begin,
163 	.write_end	= generic_write_end,
164 	.bmap		= hfs_bmap,
165 	.releasepage	= hfs_releasepage,
166 };
167 
168 const struct address_space_operations hfs_aops = {
169 	.readpage	= hfs_readpage,
170 	.writepage	= hfs_writepage,
171 	.write_begin	= hfs_write_begin,
172 	.write_end	= generic_write_end,
173 	.bmap		= hfs_bmap,
174 	.direct_IO	= hfs_direct_IO,
175 	.writepages	= hfs_writepages,
176 };
177 
178 /*
179  * hfs_new_inode
180  */
181 struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t mode)
182 {
183 	struct super_block *sb = dir->i_sb;
184 	struct inode *inode = new_inode(sb);
185 	if (!inode)
186 		return NULL;
187 
188 	mutex_init(&HFS_I(inode)->extents_lock);
189 	INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
190 	spin_lock_init(&HFS_I(inode)->open_dir_lock);
191 	hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
192 	inode->i_ino = HFS_SB(sb)->next_id++;
193 	inode->i_mode = mode;
194 	inode->i_uid = current_fsuid();
195 	inode->i_gid = current_fsgid();
196 	set_nlink(inode, 1);
197 	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
198 	HFS_I(inode)->flags = 0;
199 	HFS_I(inode)->rsrc_inode = NULL;
200 	HFS_I(inode)->fs_blocks = 0;
201 	if (S_ISDIR(mode)) {
202 		inode->i_size = 2;
203 		HFS_SB(sb)->folder_count++;
204 		if (dir->i_ino == HFS_ROOT_CNID)
205 			HFS_SB(sb)->root_dirs++;
206 		inode->i_op = &hfs_dir_inode_operations;
207 		inode->i_fop = &hfs_dir_operations;
208 		inode->i_mode |= S_IRWXUGO;
209 		inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
210 	} else if (S_ISREG(mode)) {
211 		HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
212 		HFS_SB(sb)->file_count++;
213 		if (dir->i_ino == HFS_ROOT_CNID)
214 			HFS_SB(sb)->root_files++;
215 		inode->i_op = &hfs_file_inode_operations;
216 		inode->i_fop = &hfs_file_operations;
217 		inode->i_mapping->a_ops = &hfs_aops;
218 		inode->i_mode |= S_IRUGO|S_IXUGO;
219 		if (mode & S_IWUSR)
220 			inode->i_mode |= S_IWUGO;
221 		inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
222 		HFS_I(inode)->phys_size = 0;
223 		HFS_I(inode)->alloc_blocks = 0;
224 		HFS_I(inode)->first_blocks = 0;
225 		HFS_I(inode)->cached_start = 0;
226 		HFS_I(inode)->cached_blocks = 0;
227 		memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
228 		memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
229 	}
230 	insert_inode_hash(inode);
231 	mark_inode_dirty(inode);
232 	set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
233 	hfs_mark_mdb_dirty(sb);
234 
235 	return inode;
236 }
237 
238 void hfs_delete_inode(struct inode *inode)
239 {
240 	struct super_block *sb = inode->i_sb;
241 
242 	hfs_dbg(INODE, "delete_inode: %lu\n", inode->i_ino);
243 	if (S_ISDIR(inode->i_mode)) {
244 		HFS_SB(sb)->folder_count--;
245 		if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
246 			HFS_SB(sb)->root_dirs--;
247 		set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
248 		hfs_mark_mdb_dirty(sb);
249 		return;
250 	}
251 	HFS_SB(sb)->file_count--;
252 	if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
253 		HFS_SB(sb)->root_files--;
254 	if (S_ISREG(inode->i_mode)) {
255 		if (!inode->i_nlink) {
256 			inode->i_size = 0;
257 			hfs_file_truncate(inode);
258 		}
259 	}
260 	set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
261 	hfs_mark_mdb_dirty(sb);
262 }
263 
264 void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
265 			 __be32 __log_size, __be32 phys_size, u32 clump_size)
266 {
267 	struct super_block *sb = inode->i_sb;
268 	u32 log_size = be32_to_cpu(__log_size);
269 	u16 count;
270 	int i;
271 
272 	memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
273 	for (count = 0, i = 0; i < 3; i++)
274 		count += be16_to_cpu(ext[i].count);
275 	HFS_I(inode)->first_blocks = count;
276 
277 	inode->i_size = HFS_I(inode)->phys_size = log_size;
278 	HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
279 	inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
280 	HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
281 				     HFS_SB(sb)->alloc_blksz;
282 	HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
283 	if (!HFS_I(inode)->clump_blocks)
284 		HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
285 }
286 
287 struct hfs_iget_data {
288 	struct hfs_cat_key *key;
289 	hfs_cat_rec *rec;
290 };
291 
292 static int hfs_test_inode(struct inode *inode, void *data)
293 {
294 	struct hfs_iget_data *idata = data;
295 	hfs_cat_rec *rec;
296 
297 	rec = idata->rec;
298 	switch (rec->type) {
299 	case HFS_CDR_DIR:
300 		return inode->i_ino == be32_to_cpu(rec->dir.DirID);
301 	case HFS_CDR_FIL:
302 		return inode->i_ino == be32_to_cpu(rec->file.FlNum);
303 	default:
304 		BUG();
305 		return 1;
306 	}
307 }
308 
309 /*
310  * hfs_read_inode
311  */
312 static int hfs_read_inode(struct inode *inode, void *data)
313 {
314 	struct hfs_iget_data *idata = data;
315 	struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
316 	hfs_cat_rec *rec;
317 
318 	HFS_I(inode)->flags = 0;
319 	HFS_I(inode)->rsrc_inode = NULL;
320 	mutex_init(&HFS_I(inode)->extents_lock);
321 	INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
322 	spin_lock_init(&HFS_I(inode)->open_dir_lock);
323 
324 	/* Initialize the inode */
325 	inode->i_uid = hsb->s_uid;
326 	inode->i_gid = hsb->s_gid;
327 	set_nlink(inode, 1);
328 
329 	if (idata->key)
330 		HFS_I(inode)->cat_key = *idata->key;
331 	else
332 		HFS_I(inode)->flags |= HFS_FLG_RSRC;
333 	HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
334 
335 	rec = idata->rec;
336 	switch (rec->type) {
337 	case HFS_CDR_FIL:
338 		if (!HFS_IS_RSRC(inode)) {
339 			hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
340 					    rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
341 		} else {
342 			hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
343 					    rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
344 		}
345 
346 		inode->i_ino = be32_to_cpu(rec->file.FlNum);
347 		inode->i_mode = S_IRUGO | S_IXUGO;
348 		if (!(rec->file.Flags & HFS_FIL_LOCK))
349 			inode->i_mode |= S_IWUGO;
350 		inode->i_mode &= ~hsb->s_file_umask;
351 		inode->i_mode |= S_IFREG;
352 		inode->i_ctime = inode->i_atime = inode->i_mtime =
353 				hfs_m_to_utime(rec->file.MdDat);
354 		inode->i_op = &hfs_file_inode_operations;
355 		inode->i_fop = &hfs_file_operations;
356 		inode->i_mapping->a_ops = &hfs_aops;
357 		break;
358 	case HFS_CDR_DIR:
359 		inode->i_ino = be32_to_cpu(rec->dir.DirID);
360 		inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
361 		HFS_I(inode)->fs_blocks = 0;
362 		inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
363 		inode->i_ctime = inode->i_atime = inode->i_mtime =
364 				hfs_m_to_utime(rec->dir.MdDat);
365 		inode->i_op = &hfs_dir_inode_operations;
366 		inode->i_fop = &hfs_dir_operations;
367 		break;
368 	default:
369 		make_bad_inode(inode);
370 	}
371 	return 0;
372 }
373 
374 /*
375  * __hfs_iget()
376  *
377  * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
378  * the catalog B-tree and the 'type' of the desired file return the
379  * inode for that file/directory or NULL.  Note that 'type' indicates
380  * whether we want the actual file or directory, or the corresponding
381  * metadata (AppleDouble header file or CAP metadata file).
382  */
383 struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
384 {
385 	struct hfs_iget_data data = { key, rec };
386 	struct inode *inode;
387 	u32 cnid;
388 
389 	switch (rec->type) {
390 	case HFS_CDR_DIR:
391 		cnid = be32_to_cpu(rec->dir.DirID);
392 		break;
393 	case HFS_CDR_FIL:
394 		cnid = be32_to_cpu(rec->file.FlNum);
395 		break;
396 	default:
397 		return NULL;
398 	}
399 	inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
400 	if (inode && (inode->i_state & I_NEW))
401 		unlock_new_inode(inode);
402 	return inode;
403 }
404 
405 void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
406 			  __be32 *log_size, __be32 *phys_size)
407 {
408 	memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
409 
410 	if (log_size)
411 		*log_size = cpu_to_be32(inode->i_size);
412 	if (phys_size)
413 		*phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
414 					 HFS_SB(inode->i_sb)->alloc_blksz);
415 }
416 
417 int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)
418 {
419 	struct inode *main_inode = inode;
420 	struct hfs_find_data fd;
421 	hfs_cat_rec rec;
422 	int res;
423 
424 	hfs_dbg(INODE, "hfs_write_inode: %lu\n", inode->i_ino);
425 	res = hfs_ext_write_extent(inode);
426 	if (res)
427 		return res;
428 
429 	if (inode->i_ino < HFS_FIRSTUSER_CNID) {
430 		switch (inode->i_ino) {
431 		case HFS_ROOT_CNID:
432 			break;
433 		case HFS_EXT_CNID:
434 			hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
435 			return 0;
436 		case HFS_CAT_CNID:
437 			hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
438 			return 0;
439 		default:
440 			BUG();
441 			return -EIO;
442 		}
443 	}
444 
445 	if (HFS_IS_RSRC(inode))
446 		main_inode = HFS_I(inode)->rsrc_inode;
447 
448 	if (!main_inode->i_nlink)
449 		return 0;
450 
451 	if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
452 		/* panic? */
453 		return -EIO;
454 
455 	fd.search_key->cat = HFS_I(main_inode)->cat_key;
456 	if (hfs_brec_find(&fd))
457 		/* panic? */
458 		goto out;
459 
460 	if (S_ISDIR(main_inode->i_mode)) {
461 		if (fd.entrylength < sizeof(struct hfs_cat_dir))
462 			/* panic? */;
463 		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
464 			   sizeof(struct hfs_cat_dir));
465 		if (rec.type != HFS_CDR_DIR ||
466 		    be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
467 		}
468 
469 		rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
470 		rec.dir.Val = cpu_to_be16(inode->i_size - 2);
471 
472 		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
473 			    sizeof(struct hfs_cat_dir));
474 	} else if (HFS_IS_RSRC(inode)) {
475 		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
476 			       sizeof(struct hfs_cat_file));
477 		hfs_inode_write_fork(inode, rec.file.RExtRec,
478 				     &rec.file.RLgLen, &rec.file.RPyLen);
479 		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
480 				sizeof(struct hfs_cat_file));
481 	} else {
482 		if (fd.entrylength < sizeof(struct hfs_cat_file))
483 			/* panic? */;
484 		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
485 			   sizeof(struct hfs_cat_file));
486 		if (rec.type != HFS_CDR_FIL ||
487 		    be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
488 		}
489 
490 		if (inode->i_mode & S_IWUSR)
491 			rec.file.Flags &= ~HFS_FIL_LOCK;
492 		else
493 			rec.file.Flags |= HFS_FIL_LOCK;
494 		hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
495 		rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
496 
497 		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
498 			    sizeof(struct hfs_cat_file));
499 	}
500 out:
501 	hfs_find_exit(&fd);
502 	return 0;
503 }
504 
505 static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
506 				      unsigned int flags)
507 {
508 	struct inode *inode = NULL;
509 	hfs_cat_rec rec;
510 	struct hfs_find_data fd;
511 	int res;
512 
513 	if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
514 		goto out;
515 
516 	inode = HFS_I(dir)->rsrc_inode;
517 	if (inode)
518 		goto out;
519 
520 	inode = new_inode(dir->i_sb);
521 	if (!inode)
522 		return ERR_PTR(-ENOMEM);
523 
524 	res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
525 	if (res) {
526 		iput(inode);
527 		return ERR_PTR(res);
528 	}
529 	fd.search_key->cat = HFS_I(dir)->cat_key;
530 	res = hfs_brec_read(&fd, &rec, sizeof(rec));
531 	if (!res) {
532 		struct hfs_iget_data idata = { NULL, &rec };
533 		hfs_read_inode(inode, &idata);
534 	}
535 	hfs_find_exit(&fd);
536 	if (res) {
537 		iput(inode);
538 		return ERR_PTR(res);
539 	}
540 	HFS_I(inode)->rsrc_inode = dir;
541 	HFS_I(dir)->rsrc_inode = inode;
542 	igrab(dir);
543 	hlist_add_fake(&inode->i_hash);
544 	mark_inode_dirty(inode);
545 out:
546 	d_add(dentry, inode);
547 	return NULL;
548 }
549 
550 void hfs_evict_inode(struct inode *inode)
551 {
552 	truncate_inode_pages_final(&inode->i_data);
553 	clear_inode(inode);
554 	if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
555 		HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
556 		iput(HFS_I(inode)->rsrc_inode);
557 	}
558 }
559 
560 static int hfs_file_open(struct inode *inode, struct file *file)
561 {
562 	if (HFS_IS_RSRC(inode))
563 		inode = HFS_I(inode)->rsrc_inode;
564 	atomic_inc(&HFS_I(inode)->opencnt);
565 	return 0;
566 }
567 
568 static int hfs_file_release(struct inode *inode, struct file *file)
569 {
570 	//struct super_block *sb = inode->i_sb;
571 
572 	if (HFS_IS_RSRC(inode))
573 		inode = HFS_I(inode)->rsrc_inode;
574 	if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
575 		inode_lock(inode);
576 		hfs_file_truncate(inode);
577 		//if (inode->i_flags & S_DEAD) {
578 		//	hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
579 		//	hfs_delete_inode(inode);
580 		//}
581 		inode_unlock(inode);
582 	}
583 	return 0;
584 }
585 
586 /*
587  * hfs_notify_change()
588  *
589  * Based very closely on fs/msdos/inode.c by Werner Almesberger
590  *
591  * This is the notify_change() field in the super_operations structure
592  * for HFS file systems.  The purpose is to take that changes made to
593  * an inode and apply then in a filesystem-dependent manner.  In this
594  * case the process has a few of tasks to do:
595  *  1) prevent changes to the i_uid and i_gid fields.
596  *  2) map file permissions to the closest allowable permissions
597  *  3) Since multiple Linux files can share the same on-disk inode under
598  *     HFS (for instance the data and resource forks of a file) a change
599  *     to permissions must be applied to all other in-core inodes which
600  *     correspond to the same HFS file.
601  */
602 
603 int hfs_inode_setattr(struct dentry *dentry, struct iattr * attr)
604 {
605 	struct inode *inode = d_inode(dentry);
606 	struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
607 	int error;
608 
609 	error = setattr_prepare(dentry, attr); /* basic permission checks */
610 	if (error)
611 		return error;
612 
613 	/* no uig/gid changes and limit which mode bits can be set */
614 	if (((attr->ia_valid & ATTR_UID) &&
615 	     (!uid_eq(attr->ia_uid, hsb->s_uid))) ||
616 	    ((attr->ia_valid & ATTR_GID) &&
617 	     (!gid_eq(attr->ia_gid, hsb->s_gid))) ||
618 	    ((attr->ia_valid & ATTR_MODE) &&
619 	     ((S_ISDIR(inode->i_mode) &&
620 	       (attr->ia_mode != inode->i_mode)) ||
621 	      (attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
622 		return hsb->s_quiet ? 0 : error;
623 	}
624 
625 	if (attr->ia_valid & ATTR_MODE) {
626 		/* Only the 'w' bits can ever change and only all together. */
627 		if (attr->ia_mode & S_IWUSR)
628 			attr->ia_mode = inode->i_mode | S_IWUGO;
629 		else
630 			attr->ia_mode = inode->i_mode & ~S_IWUGO;
631 		attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
632 	}
633 
634 	if ((attr->ia_valid & ATTR_SIZE) &&
635 	    attr->ia_size != i_size_read(inode)) {
636 		inode_dio_wait(inode);
637 
638 		error = inode_newsize_ok(inode, attr->ia_size);
639 		if (error)
640 			return error;
641 
642 		truncate_setsize(inode, attr->ia_size);
643 		hfs_file_truncate(inode);
644 	}
645 
646 	setattr_copy(inode, attr);
647 	mark_inode_dirty(inode);
648 	return 0;
649 }
650 
651 static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
652 			  int datasync)
653 {
654 	struct inode *inode = filp->f_mapping->host;
655 	struct super_block * sb;
656 	int ret, err;
657 
658 	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
659 	if (ret)
660 		return ret;
661 	inode_lock(inode);
662 
663 	/* sync the inode to buffers */
664 	ret = write_inode_now(inode, 0);
665 
666 	/* sync the superblock to buffers */
667 	sb = inode->i_sb;
668 	flush_delayed_work(&HFS_SB(sb)->mdb_work);
669 	/* .. finally sync the buffers to disk */
670 	err = sync_blockdev(sb->s_bdev);
671 	if (!ret)
672 		ret = err;
673 	inode_unlock(inode);
674 	return ret;
675 }
676 
677 static const struct file_operations hfs_file_operations = {
678 	.llseek		= generic_file_llseek,
679 	.read_iter	= generic_file_read_iter,
680 	.write_iter	= generic_file_write_iter,
681 	.mmap		= generic_file_mmap,
682 	.splice_read	= generic_file_splice_read,
683 	.fsync		= hfs_file_fsync,
684 	.open		= hfs_file_open,
685 	.release	= hfs_file_release,
686 };
687 
688 static const struct inode_operations hfs_file_inode_operations = {
689 	.lookup		= hfs_file_lookup,
690 	.setattr	= hfs_inode_setattr,
691 	.listxattr	= generic_listxattr,
692 };
693