[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 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,
			struct dir_context *ctx,
			unsigned de_inode)
{
	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 */
		pr_err("invalid direntry size (%i).\n", de->de_size);
		return 0;
	}
	lf = qnx6_longname(s, de, &page);
	if (IS_ERR(lf)) {
		pr_err("Error reading longname\n");
		return 0;
	}

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

	if (lf_size > QNX6_LONG_NAME_MAX) {
		pr_debug("file %s\n", lf->lf_fname);
		pr_err("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))
		pr_info("long filename checksum error.\n");

	pr_debug("qnx6_readdir:%.*s inode:%u\n",
		 lf_size, lf->lf_fname, de_inode);
	if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) {
		qnx6_put_page(page);
		return 0;
	}

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

static int qnx6_readdir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	struct super_block *s = inode->i_sb;
	struct qnx6_sb_info *sbi = QNX6_SB(s);
	loff_t pos = ctx->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;

	ctx->pos = pos;
	if (ctx->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)) {
			pr_err("%s(): read failed\n", __func__);
			ctx->pos = (n + 1) << PAGE_CACHE_SHIFT;
			return PTR_ERR(page);
		}
		de = ((struct qnx6_dir_entry *)page_address(page)) + start;
		for (; i < limit; i++, de++, ctx->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,
					ctx, no_inode)) {
					done = true;
					break;
				}
			} else {
				pr_debug("%s():%.*s inode:%u\n",
					 __func__, size, de->de_fname,
					 no_inode);
				if (!dir_emit(ctx, de->de_fname, size,
				      no_inode, DT_UNKNOWN)) {
					done = true;
					break;
				}
			}
		}
		qnx6_put_page(page);
	}
	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
					pr_err("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,
	.iterate	= 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
5d026c72 KB	35	static unsigned last_entry(struct inode *inode, unsigned long page_nr)
	36	{
	37	unsigned long last_byte = inode->i_size;
	38	last_byte -= page_nr << PAGE_CACHE_SHIFT;
	39	if (last_byte > PAGE_CACHE_SIZE)
	40	last_byte = PAGE_CACHE_SIZE;
	41	return last_byte / QNX6_DIR_ENTRY_SIZE;
	42	}
	43
	44	static struct qnx6_long_filename qnx6_longname(struct super_block sb,
	45	struct qnx6_long_dir_entry *de,
	46	struct page **p)
	47	{
	48	struct qnx6_sb_info *sbi = QNX6_SB(sb);
	49	u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
	50	u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */
	51	/* within page */
	52	u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK;
	53	struct address_space *mapping = sbi->longfile->i_mapping;
	54	struct page *page = read_mapping_page(mapping, n, NULL);
	55	if (IS_ERR(page))
	56	return ERR_CAST(page);
	57	kmap(*p = page);
	58	return (struct qnx6_long_filename *)(page_address(page) + offs);
	59	}
	60
	61	static int qnx6_dir_longfilename(struct inode *inode,
	62	struct qnx6_long_dir_entry *de,
4deb398a AV	63	struct dir_context *ctx,
4deb398a AV	64	unsigned de_inode)
5d026c72 KB	65	{
	66	struct qnx6_long_filename *lf;
	67	struct super_block *s = inode->i_sb;
	68	struct qnx6_sb_info *sbi = QNX6_SB(s);
	69	struct page *page;
	70	int lf_size;
	71
	72	if (de->de_size != 0xff) {
	73	/* error - long filename entries always have size 0xff
	74	in direntry */
e6c32616	75	pr_err("invalid direntry size (%i).\n", de->de_size);
5d026c72 KB	76	return 0;
	77	}
	78	lf = qnx6_longname(s, de, &page);
	79	if (IS_ERR(lf)) {
e6c32616	80	pr_err("Error reading longname\n");
5d026c72 KB	81	return 0;
	82	}
	83
	84	lf_size = fs16_to_cpu(sbi, lf->lf_size);
	85
	86	if (lf_size > QNX6_LONG_NAME_MAX) {
fa5a7a41	87	pr_debug("file %s\n", lf->lf_fname);
e6c32616	88	pr_err("Filename too long (%i)\n", lf_size);
5d026c72 KB	89	qnx6_put_page(page);
	90	return 0;
	91	}
	92
	93	/* calc & validate longfilename checksum
	94	mmi 3g filesystem does not have that checksum */
	95	if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
	96	qnx6_lfile_checksum(lf->lf_fname, lf_size))
e6c32616	97	pr_info("long filename checksum error.\n");
5d026c72	98
fa5a7a41 FF	99	pr_debug("qnx6_readdir:%.*s inode:%u\n",
fa5a7a41 FF	100	lf_size, lf->lf_fname, de_inode);
4deb398a	101	if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) {
5d026c72 KB	102	qnx6_put_page(page);
	103	return 0;
	104	}
	105
	106	qnx6_put_page(page);
	107	/* success */
	108	return 1;
	109	}
	110
4deb398a	111	static int qnx6_readdir(struct file file, struct dir_context ctx)
5d026c72	112	{
4deb398a	113	struct inode *inode = file_inode(file);
5d026c72 KB	114	struct super_block *s = inode->i_sb;
5d026c72 KB	115	struct qnx6_sb_info *sbi = QNX6_SB(s);
4deb398a	116	loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1);
5d026c72 KB	117	unsigned long npages = dir_pages(inode);
	118	unsigned long n = pos >> PAGE_CACHE_SHIFT;
	119	unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE;
	120	bool done = false;
	121
4deb398a AV	122	ctx->pos = pos;
4deb398a AV	123	if (ctx->pos >= inode->i_size)
5d026c72 KB	124	return 0;
	125
	126	for ( ; !done && n < npages; n++, start = 0) {
	127	struct page *page = qnx6_get_page(inode, n);
	128	int limit = last_entry(inode, n);
	129	struct qnx6_dir_entry *de;
	130	int i = start;
	131
	132	if (IS_ERR(page)) {
e6c32616	133	pr_err("%s(): read failed\n", __func__);
4deb398a	134	ctx->pos = (n + 1) << PAGE_CACHE_SHIFT;
5d026c72 KB	135	return PTR_ERR(page);
	136	}
	137	de = ((struct qnx6_dir_entry *)page_address(page)) + start;
4deb398a	138	for (; i < limit; i++, de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) {
5d026c72 KB	139	int size = de->de_size;
	140	u32 no_inode = fs32_to_cpu(sbi, de->de_inode);
	141
	142	if (!no_inode \|\| !size)
	143	continue;
	144
	145	if (size > QNX6_SHORT_NAME_MAX) {
	146	/* long filename detected
	147	get the filename from long filename
	148	structure / block */
	149	if (!qnx6_dir_longfilename(inode,
	150	(struct qnx6_long_dir_entry *)de,
4deb398a	151	ctx, no_inode)) {
5d026c72 KB	152	done = true;
	153	break;
	154	}
	155	} else {
fa5a7a41 FF	156	pr_debug("%s():%.*s inode:%u\n",
	157	__func__, size, de->de_fname,
	158	no_inode);
4deb398a AV	159	if (!dir_emit(ctx, de->de_fname, size,
4deb398a AV	160	no_inode, DT_UNKNOWN)) {
5d026c72 KB	161	done = true;
	162	break;
	163	}
	164	}
	165	}
	166	qnx6_put_page(page);
	167	}
5d026c72 KB	168	return 0;
	169	}
	170
	171	/*
	172	* check if the long filename is correct.
	173	*/
	174	static unsigned qnx6_long_match(int len, const char *name,
	175	struct qnx6_long_dir_entry de, struct inode dir)
	176	{
	177	struct super_block *s = dir->i_sb;
	178	struct qnx6_sb_info *sbi = QNX6_SB(s);
	179	struct page *page;
	180	int thislen;
	181	struct qnx6_long_filename *lf = qnx6_longname(s, de, &page);
	182
	183	if (IS_ERR(lf))
	184	return 0;
	185
	186	thislen = fs16_to_cpu(sbi, lf->lf_size);
	187	if (len != thislen) {
	188	qnx6_put_page(page);
	189	return 0;
	190	}
	191	if (memcmp(name, lf->lf_fname, len) == 0) {
	192	qnx6_put_page(page);
	193	return fs32_to_cpu(sbi, de->de_inode);
	194	}
	195	qnx6_put_page(page);
	196	return 0;
	197	}
	198
	199	/*
	200	* check if the filename is correct.
	201	*/
	202	static unsigned qnx6_match(struct super_block s, int len, const char name,
	203	struct qnx6_dir_entry *de)
	204	{
	205	struct qnx6_sb_info *sbi = QNX6_SB(s);
	206	if (memcmp(name, de->de_fname, len) == 0)
	207	return fs32_to_cpu(sbi, de->de_inode);
	208	return 0;
	209	}
	210
	211
	212	unsigned qnx6_find_entry(int len, struct inode dir, const char name,
	213	struct page **res_page)
	214	{
	215	struct super_block *s = dir->i_sb;
	216	struct qnx6_inode_info *ei = QNX6_I(dir);
	217	struct page *page = NULL;
	218	unsigned long start, n;
	219	unsigned long npages = dir_pages(dir);
	220	unsigned ino;
	221	struct qnx6_dir_entry *de;
	222	struct qnx6_long_dir_entry *lde;
	223
	224	*res_page = NULL;
	225
	226	if (npages == 0)
	227	return 0;
	228	start = ei->i_dir_start_lookup;
	229	if (start >= npages)
	230	start = 0;
	231	n = start;
232
233	do {
234	page = qnx6_get_page(dir, n);
235	if (!IS_ERR(page)) {
236	int limit = last_entry(dir, n);
237	int i;
238
239	de = (struct qnx6_dir_entry *)page_address(page);
240	for (i = 0; i < limit; i++, de++) {
241	if (len <= QNX6_SHORT_NAME_MAX) {
242	/* short filename */
243	if (len != de->de_size)
244	continue;
245	ino = qnx6_match(s, len, name, de);
246	if (ino)
247	goto found;
248	} else if (de->de_size == 0xff) {
249	/* deal with long filename */
250	lde = (struct qnx6_long_dir_entry *)de;
251	ino = qnx6_long_match(len,
252	name, lde, dir);
253	if (ino)
254	goto found;
255	} else
e6c32616	256	pr_err("undefined filename size in inode.\n");
5d026c72 KB	257	}
	258	qnx6_put_page(page);
	259	}
	260
	261	if (++n >= npages)
	262	n = 0;
	263	} while (n != start);
	264	return 0;
	265
	266	found:
	267	*res_page = page;
	268	ei->i_dir_start_lookup = n;
	269	return ino;
	270	}
	271
	272	const struct file_operations qnx6_dir_operations = {
	273	.llseek = generic_file_llseek,
	274	.read = generic_read_dir,
4deb398a	275	.iterate = qnx6_readdir,
5d026c72 KB	276	.fsync = generic_file_fsync,
	277	};
	278
	279	const struct inode_operations qnx6_dir_inode_operations = {
	280	.lookup = qnx6_lookup,
	281	};