[linux.git] / fs / qnx6 / dir.c

/*
 * QNX6 file system, Linux implementation.
 *
 * Version : 1.0.0
 *
 * History :
 *
 * 01-02-2012 by Kai Bankett ([email protected]) : first release.
 * 16-02-2012 pagemap extension by Al Viro
 *
 */

#include "qnx6.h"

static unsigned qnx6_lfile_checksum(char *name, unsigned size)
{
	unsigned crc = 0;
	char *end = name + size;
	while (name < end) {
		crc = ((crc >> 1) + *(name++)) ^
			((crc & 0x00000001) ? 0x80000000 : 0);
	}
	return crc;
}

static struct page *qnx6_get_page(struct inode *dir, unsigned long n)
{
	struct address_space *mapping = dir->i_mapping;
	struct page *page = read_mapping_page(mapping, n, NULL);
	if (!IS_ERR(page))
		kmap(page);
	return page;
}

static inline unsigned long dir_pages(struct inode *inode)
{
	return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
}

static unsigned last_entry(struct inode *inode, unsigned long page_nr)
{
	unsigned long last_byte = inode->i_size;
	last_byte -= page_nr << PAGE_CACHE_SHIFT;
	if (last_byte > PAGE_CACHE_SIZE)
		last_byte = PAGE_CACHE_SIZE;
	return last_byte / QNX6_DIR_ENTRY_SIZE;
}

static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
					 struct qnx6_long_dir_entry *de,
					 struct page **p)
{
	struct qnx6_sb_info *sbi = QNX6_SB(sb);
	u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
	u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */
	/* within page */
	u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK;
	struct address_space *mapping = sbi->longfile->i_mapping;
	struct page *page = read_mapping_page(mapping, n, NULL);
	if (IS_ERR(page))
		return ERR_CAST(page);
	kmap(*p = page);
	return (struct qnx6_long_filename *)(page_address(page) + offs);
}

static int qnx6_dir_longfilename(struct inode *inode,
			struct qnx6_long_dir_entry *de,
			void *dirent, loff_t pos,
			unsigned de_inode, filldir_t filldir)
{
	struct qnx6_long_filename *lf;
	struct super_block *s = inode->i_sb;
	struct qnx6_sb_info *sbi = QNX6_SB(s);
	struct page *page;
	int lf_size;

	if (de->de_size != 0xff) {
		/* error - long filename entries always have size 0xff
		   in direntry */
		printk(KERN_ERR "qnx6: invalid direntry size (%i).\n",
				de->de_size);
		return 0;
	}
	lf = qnx6_longname(s, de, &page);
	if (IS_ERR(lf)) {
		printk(KERN_ERR "qnx6:Error reading longname\n");
		return 0;
	}

	lf_size = fs16_to_cpu(sbi, lf->lf_size);

	if (lf_size > QNX6_LONG_NAME_MAX) {
		QNX6DEBUG((KERN_INFO "file %s\n", lf->lf_fname));
		printk(KERN_ERR "qnx6:Filename too long (%i)\n", lf_size);
		qnx6_put_page(page);
		return 0;
	}

	/* calc & validate longfilename checksum
	   mmi 3g filesystem does not have that checksum */
	if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
			qnx6_lfile_checksum(lf->lf_fname, lf_size))
		printk(KERN_INFO "qnx6: long filename checksum error.\n");

	QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s inode:%u\n",
					lf_size, lf->lf_fname, de_inode));
	if (filldir(dirent, lf->lf_fname, lf_size, pos, de_inode,
			DT_UNKNOWN) < 0) {
		qnx6_put_page(page);
		return 0;
	}

	qnx6_put_page(page);
	/* success */
	return 1;
}

static int qnx6_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
	struct inode *inode = filp->f_path.dentry->d_inode;
	struct super_block *s = inode->i_sb;
	struct qnx6_sb_info *sbi = QNX6_SB(s);
	loff_t pos = filp->f_pos & (QNX6_DIR_ENTRY_SIZE - 1);
	unsigned long npages = dir_pages(inode);
	unsigned long n = pos >> PAGE_CACHE_SHIFT;
	unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE;
	bool done = false;

	if (filp->f_pos >= inode->i_size)
		return 0;

	for ( ; !done && n < npages; n++, start = 0) {
		struct page *page = qnx6_get_page(inode, n);
		int limit = last_entry(inode, n);
		struct qnx6_dir_entry *de;
		int i = start;

		if (IS_ERR(page)) {
			printk(KERN_ERR "qnx6_readdir: read failed\n");
			filp->f_pos = (n + 1) << PAGE_CACHE_SHIFT;
			return PTR_ERR(page);
		}
		de = ((struct qnx6_dir_entry *)page_address(page)) + start;
		for (; i < limit; i++, de++, pos += QNX6_DIR_ENTRY_SIZE) {
			int size = de->de_size;
			u32 no_inode = fs32_to_cpu(sbi, de->de_inode);

			if (!no_inode || !size)
				continue;

			if (size > QNX6_SHORT_NAME_MAX) {
				/* long filename detected
				   get the filename from long filename
				   structure / block */
				if (!qnx6_dir_longfilename(inode,
					(struct qnx6_long_dir_entry *)de,
					dirent, pos, no_inode,
					filldir)) {
					done = true;
					break;
				}
			} else {
				QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s"
				   " inode:%u\n", size, de->de_fname,
							no_inode));
				if (filldir(dirent, de->de_fname, size,
				      pos, no_inode, DT_UNKNOWN)
					< 0) {
					done = true;
					break;
				}
			}
		}
		qnx6_put_page(page);
	}
	filp->f_pos = pos;
	return 0;
}

/*
 * check if the long filename is correct.
 */
static unsigned qnx6_long_match(int len, const char *name,
			struct qnx6_long_dir_entry *de, struct inode *dir)
{
	struct super_block *s = dir->i_sb;
	struct qnx6_sb_info *sbi = QNX6_SB(s);
	struct page *page;
	int thislen;
	struct qnx6_long_filename *lf = qnx6_longname(s, de, &page);

	if (IS_ERR(lf))
		return 0;

	thislen = fs16_to_cpu(sbi, lf->lf_size);
	if (len != thislen) {
		qnx6_put_page(page);
		return 0;
	}
	if (memcmp(name, lf->lf_fname, len) == 0) {
		qnx6_put_page(page);
		return fs32_to_cpu(sbi, de->de_inode);
	}
	qnx6_put_page(page);
	return 0;
}

/*
 * check if the filename is correct.
 */
static unsigned qnx6_match(struct super_block *s, int len, const char *name,
			struct qnx6_dir_entry *de)
{
	struct qnx6_sb_info *sbi = QNX6_SB(s);
	if (memcmp(name, de->de_fname, len) == 0)
		return fs32_to_cpu(sbi, de->de_inode);
	return 0;
}


unsigned qnx6_find_entry(int len, struct inode *dir, const char *name,
			 struct page **res_page)
{
	struct super_block *s = dir->i_sb;
	struct qnx6_inode_info *ei = QNX6_I(dir);
	struct page *page = NULL;
	unsigned long start, n;
	unsigned long npages = dir_pages(dir);
	unsigned ino;
	struct qnx6_dir_entry *de;
	struct qnx6_long_dir_entry *lde;

	*res_page = NULL;

	if (npages == 0)
		return 0;
	start = ei->i_dir_start_lookup;
	if (start >= npages)
		start = 0;
	n = start;

	do {
		page = qnx6_get_page(dir, n);
		if (!IS_ERR(page)) {
			int limit = last_entry(dir, n);
			int i;

			de = (struct qnx6_dir_entry *)page_address(page);
			for (i = 0; i < limit; i++, de++) {
				if (len <= QNX6_SHORT_NAME_MAX) {
					/* short filename */
					if (len != de->de_size)
						continue;
					ino = qnx6_match(s, len, name, de);
					if (ino)
						goto found;
				} else if (de->de_size == 0xff) {
					/* deal with long filename */
					lde = (struct qnx6_long_dir_entry *)de;
					ino = qnx6_long_match(len,
								name, lde, dir);
					if (ino)
						goto found;
				} else
					printk(KERN_ERR "qnx6: undefined "
						"filename size in inode.\n");
			}
			qnx6_put_page(page);
		}

		if (++n >= npages)
			n = 0;
	} while (n != start);
	return 0;

found:
	*res_page = page;
	ei->i_dir_start_lookup = n;
	return ino;
}

const struct file_operations qnx6_dir_operations = {
	.llseek		= generic_file_llseek,
	.read		= generic_read_dir,
	.readdir	= qnx6_readdir,
	.fsync		= generic_file_fsync,
};

const struct inode_operations qnx6_dir_inode_operations = {
	.lookup		= qnx6_lookup,
};
Commit	Line	Data
5d026c72 KB	1	/*
	2	* QNX6 file system, Linux implementation.
	3	*
	4	* Version : 1.0.0
	5	*
	6	* History :
	7	*
	8	* 01-02-2012 by Kai Bankett ([email protected]) : first release.
	9	* 16-02-2012 pagemap extension by Al Viro
	10	*
	11	*/
	12
	13	#include "qnx6.h"
	14
	15	static unsigned qnx6_lfile_checksum(char *name, unsigned size)
	16	{
	17	unsigned crc = 0;
	18	char *end = name + size;
	19	while (name < end) {
	20	crc = ((crc >> 1) + *(name++)) ^
	21	((crc & 0x00000001) ? 0x80000000 : 0);
	22	}
	23	return crc;
	24	}
	25
	26	static struct page qnx6_get_page(struct inode dir, unsigned long n)
	27	{
	28	struct address_space *mapping = dir->i_mapping;
	29	struct page *page = read_mapping_page(mapping, n, NULL);
	30	if (!IS_ERR(page))
	31	kmap(page);
	32	return page;
	33	}
	34
	35	static inline unsigned long dir_pages(struct inode *inode)
	36	{
	37	return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
	38	}
	39
	40	static unsigned last_entry(struct inode *inode, unsigned long page_nr)
	41	{
	42	unsigned long last_byte = inode->i_size;
	43	last_byte -= page_nr << PAGE_CACHE_SHIFT;
	44	if (last_byte > PAGE_CACHE_SIZE)
	45	last_byte = PAGE_CACHE_SIZE;
	46	return last_byte / QNX6_DIR_ENTRY_SIZE;
	47	}
	48
	49	static struct qnx6_long_filename qnx6_longname(struct super_block sb,
	50	struct qnx6_long_dir_entry *de,
	51	struct page **p)
	52	{
	53	struct qnx6_sb_info *sbi = QNX6_SB(sb);
	54	u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
	55	u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */
	56	/* within page */
	57	u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK;
	58	struct address_space *mapping = sbi->longfile->i_mapping;
	59	struct page *page = read_mapping_page(mapping, n, NULL);
	60	if (IS_ERR(page))
	61	return ERR_CAST(page);
	62	kmap(*p = page);
	63	return (struct qnx6_long_filename *)(page_address(page) + offs);
	64	}
65
66	static int qnx6_dir_longfilename(struct inode *inode,
67	struct qnx6_long_dir_entry *de,
68	void *dirent, loff_t pos,
69	unsigned de_inode, filldir_t filldir)
70	{
71	struct qnx6_long_filename *lf;
72	struct super_block *s = inode->i_sb;
73	struct qnx6_sb_info *sbi = QNX6_SB(s);
74	struct page *page;
75	int lf_size;
76
77	if (de->de_size != 0xff) {
78	/* error - long filename entries always have size 0xff
79	in direntry */
80	printk(KERN_ERR "qnx6: invalid direntry size (%i).\n",
81	de->de_size);
82	return 0;
83	}
84	lf = qnx6_longname(s, de, &page);
85	if (IS_ERR(lf)) {
86	printk(KERN_ERR "qnx6:Error reading longname\n");
87	return 0;
88	}
89
90	lf_size = fs16_to_cpu(sbi, lf->lf_size);
91
92	if (lf_size > QNX6_LONG_NAME_MAX) {
93	QNX6DEBUG((KERN_INFO "file %s\n", lf->lf_fname));
94	printk(KERN_ERR "qnx6:Filename too long (%i)\n", lf_size);
95	qnx6_put_page(page);
96	return 0;
97	}
98
99	/* calc & validate longfilename checksum
100	mmi 3g filesystem does not have that checksum */
101	if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
102	qnx6_lfile_checksum(lf->lf_fname, lf_size))
103	printk(KERN_INFO "qnx6: long filename checksum error.\n");
104
105	QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s inode:%u\n",
106	lf_size, lf->lf_fname, de_inode));
107	if (filldir(dirent, lf->lf_fname, lf_size, pos, de_inode,
108	DT_UNKNOWN) < 0) {
109	qnx6_put_page(page);
110	return 0;
111	}
112
113	qnx6_put_page(page);
114	/* success */
115	return 1;
116	}
117
118	static int qnx6_readdir(struct file filp, void dirent, filldir_t filldir)
119	{
120	struct inode *inode = filp->f_path.dentry->d_inode;
121	struct super_block *s = inode->i_sb;
122	struct qnx6_sb_info *sbi = QNX6_SB(s);
123	loff_t pos = filp->f_pos & (QNX6_DIR_ENTRY_SIZE - 1);
124	unsigned long npages = dir_pages(inode);
125	unsigned long n = pos >> PAGE_CACHE_SHIFT;
126	unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE;
127	bool done = false;
128
129	if (filp->f_pos >= inode->i_size)
130	return 0;
131
132	for ( ; !done && n < npages; n++, start = 0) {
133	struct page *page = qnx6_get_page(inode, n);
134	int limit = last_entry(inode, n);
135	struct qnx6_dir_entry *de;
136	int i = start;
137
138	if (IS_ERR(page)) {
139	printk(KERN_ERR "qnx6_readdir: read failed\n");
140	filp->f_pos = (n + 1) << PAGE_CACHE_SHIFT;
141	return PTR_ERR(page);
142	}
143	de = ((struct qnx6_dir_entry *)page_address(page)) + start;
144	for (; i < limit; i++, de++, pos += QNX6_DIR_ENTRY_SIZE) {
145	int size = de->de_size;
146	u32 no_inode = fs32_to_cpu(sbi, de->de_inode);
147
148	if (!no_inode \|\| !size)
149	continue;
150
151	if (size > QNX6_SHORT_NAME_MAX) {
152	/* long filename detected
153	get the filename from long filename
154	structure / block */
155	if (!qnx6_dir_longfilename(inode,
156	(struct qnx6_long_dir_entry *)de,
157	dirent, pos, no_inode,
158	filldir)) {
159	done = true;
160	break;
161	}
162	} else {
163	QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s"
164	" inode:%u\n", size, de->de_fname,
165	no_inode));
166	if (filldir(dirent, de->de_fname, size,
167	pos, no_inode, DT_UNKNOWN)
168	< 0) {
169	done = true;
170	break;
171	}
172	}
173	}
174	qnx6_put_page(page);
175	}
176	filp->f_pos = pos;
177	return 0;
178	}
179
180	/*
181	* check if the long filename is correct.
182	*/
183	static unsigned qnx6_long_match(int len, const char *name,
184	struct qnx6_long_dir_entry de, struct inode dir)
185	{
186	struct super_block *s = dir->i_sb;
187	struct qnx6_sb_info *sbi = QNX6_SB(s);
188	struct page *page;
189	int thislen;
190	struct qnx6_long_filename *lf = qnx6_longname(s, de, &page);
191
192	if (IS_ERR(lf))
193	return 0;
194
195	thislen = fs16_to_cpu(sbi, lf->lf_size);
196	if (len != thislen) {
197	qnx6_put_page(page);
198	return 0;
199	}
200	if (memcmp(name, lf->lf_fname, len) == 0) {
201	qnx6_put_page(page);
202	return fs32_to_cpu(sbi, de->de_inode);
203	}
204	qnx6_put_page(page);
205	return 0;
206	}
207
208	/*
209	* check if the filename is correct.
210	*/
211	static unsigned qnx6_match(struct super_block s, int len, const char name,
212	struct qnx6_dir_entry *de)
213	{
214	struct qnx6_sb_info *sbi = QNX6_SB(s);
215	if (memcmp(name, de->de_fname, len) == 0)
216	return fs32_to_cpu(sbi, de->de_inode);
217	return 0;
218	}
219
220
221	unsigned qnx6_find_entry(int len, struct inode dir, const char name,
222	struct page **res_page)
223	{
224	struct super_block *s = dir->i_sb;
225	struct qnx6_inode_info *ei = QNX6_I(dir);
226	struct page *page = NULL;
227	unsigned long start, n;
228	unsigned long npages = dir_pages(dir);
229	unsigned ino;
230	struct qnx6_dir_entry *de;
231	struct qnx6_long_dir_entry *lde;
232
233	*res_page = NULL;
234
235	if (npages == 0)
236	return 0;
237	start = ei->i_dir_start_lookup;
238	if (start >= npages)
239	start = 0;
240	n = start;
241
242	do {
243	page = qnx6_get_page(dir, n);
244	if (!IS_ERR(page)) {
245	int limit = last_entry(dir, n);
246	int i;
247
248	de = (struct qnx6_dir_entry *)page_address(page);
249	for (i = 0; i < limit; i++, de++) {
250	if (len <= QNX6_SHORT_NAME_MAX) {
251	/* short filename */
252	if (len != de->de_size)
253	continue;
254	ino = qnx6_match(s, len, name, de);
255	if (ino)
256	goto found;
257	} else if (de->de_size == 0xff) {
258	/* deal with long filename */
259	lde = (struct qnx6_long_dir_entry *)de;
260	ino = qnx6_long_match(len,
261	name, lde, dir);
262	if (ino)
263	goto found;
264	} else
265	printk(KERN_ERR "qnx6: undefined "
266	"filename size in inode.\n");
267	}
268	qnx6_put_page(page);
269	}
270
271	if (++n >= npages)
272	n = 0;
273	} while (n != start);
274	return 0;
275
276	found:
277	*res_page = page;
278	ei->i_dir_start_lookup = n;
279	return ino;
280	}
281
282	const struct file_operations qnx6_dir_operations = {
283	.llseek = generic_file_llseek,
284	.read = generic_read_dir,
285	.readdir = qnx6_readdir,
286	.fsync = generic_file_fsync,
287	};
288
289	const struct inode_operations qnx6_dir_inode_operations = {
290	.lookup = qnx6_lookup,
291	};