1/*
   2 *  linux/fs/fat/dir.c
   3 *
   4 *  directory handling functions for fat-based filesystems
   5 *
   6 *  Written 1992,1993 by Werner Almesberger
   7 *
   8 *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
   9 *
  10 *  VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>
  11 *  Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>
  12 *  Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
  13 *  Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
  14 */
  15
  16#include <linux/slab.h>
  17#include <linux/compat.h>
  18#include <linux/uaccess.h>
 
  19#include "fat.h"
  20
  21/*
  22 * Maximum buffer size of short name.
  23 * [(MSDOS_NAME + '.') * max one char + nul]
  24 * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
  25 */
  26#define FAT_MAX_SHORT_SIZE	((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
  27/*
  28 * Maximum buffer size of unicode chars from slots.
  29 * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
  30 */
  31#define FAT_MAX_UNI_CHARS	((MSDOS_SLOTS - 1) * 13 + 1)
  32#define FAT_MAX_UNI_SIZE	(FAT_MAX_UNI_CHARS * sizeof(wchar_t))
  33
  34static inline unsigned char fat_tolower(unsigned char c)
  35{
  36	return ((c >= 'A') && (c <= 'Z')) ? c+32 : c;
  37}
  38
  39static inline loff_t fat_make_i_pos(struct super_block *sb,
  40				    struct buffer_head *bh,
  41				    struct msdos_dir_entry *de)
  42{
  43	return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
  44		| (de - (struct msdos_dir_entry *)bh->b_data);
  45}
  46
  47static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
  48				     sector_t phys)
  49{
  50	struct super_block *sb = dir->i_sb;
  51	struct msdos_sb_info *sbi = MSDOS_SB(sb);
  52	struct buffer_head *bh;
  53	int sec;
  54
  55	/* This is not a first sector of cluster, or sec_per_clus == 1 */
  56	if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
  57		return;
  58	/* root dir of FAT12/FAT16 */
  59	if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
  60		return;
  61
  62	bh = sb_find_get_block(sb, phys);
  63	if (bh == NULL || !buffer_uptodate(bh)) {
  64		for (sec = 0; sec < sbi->sec_per_clus; sec++)
  65			sb_breadahead(sb, phys + sec);
  66	}
  67	brelse(bh);
  68}
  69
  70/* Returns the inode number of the directory entry at offset pos. If bh is
  71   non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
  72   returned in bh.
  73   AV. Most often we do it item-by-item. Makes sense to optimize.
  74   AV. OK, there we go: if both bh and de are non-NULL we assume that we just
  75   AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
  76   AV. It's done in fat_get_entry() (inlined), here the slow case lives.
  77   AV. Additionally, when we return -1 (i.e. reached the end of directory)
  78   AV. we make bh NULL.
  79 */
  80static int fat__get_entry(struct inode *dir, loff_t *pos,
  81			  struct buffer_head **bh, struct msdos_dir_entry **de)
  82{
  83	struct super_block *sb = dir->i_sb;
  84	sector_t phys, iblock;
  85	unsigned long mapped_blocks;
  86	int err, offset;
  87
  88next:
  89	if (*bh)
  90		brelse(*bh);
  91
  92	*bh = NULL;
  93	iblock = *pos >> sb->s_blocksize_bits;
  94	err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0, false);
  95	if (err || !phys)
  96		return -1;	/* beyond EOF or error */
  97
  98	fat_dir_readahead(dir, iblock, phys);
  99
 100	*bh = sb_bread(sb, phys);
 101	if (*bh == NULL) {
 102		fat_msg_ratelimit(sb, KERN_ERR,
 103			"Directory bread(block %llu) failed", (llu)phys);
 104		/* skip this block */
 105		*pos = (iblock + 1) << sb->s_blocksize_bits;
 106		goto next;
 107	}
 108
 109	offset = *pos & (sb->s_blocksize - 1);
 110	*pos += sizeof(struct msdos_dir_entry);
 111	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
 112
 113	return 0;
 114}
 115
 116static inline int fat_get_entry(struct inode *dir, loff_t *pos,
 117				struct buffer_head **bh,
 118				struct msdos_dir_entry **de)
 119{
 120	/* Fast stuff first */
 121	if (*bh && *de &&
 122	   (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
 123				MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
 124		*pos += sizeof(struct msdos_dir_entry);
 125		(*de)++;
 126		return 0;
 127	}
 128	return fat__get_entry(dir, pos, bh, de);
 129}
 130
 131/*
 132 * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
 133 * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
 134 * colon as an escape character since it is normally invalid on the vfat
 135 * filesystem. The following four characters are the hexadecimal digits
 136 * of Unicode value. This lets us do a full dump and restore of Unicode
 137 * filenames. We could get into some trouble with long Unicode names,
 138 * but ignore that right now.
 139 * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
 140 */
 141static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
 142		       const wchar_t *uni, int len, struct nls_table *nls)
 143{
 144	int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
 145	const wchar_t *ip;
 146	wchar_t ec;
 147	unsigned char *op;
 148	int charlen;
 149
 150	ip = uni;
 151	op = ascii;
 152
 153	while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
 154		ec = *ip++;
 155		charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);
 156		if (charlen > 0) {
 157			op += charlen;
 158			len -= charlen;
 159		} else {
 160			if (uni_xlate == 1) {
 161				*op++ = ':';
 162				op = hex_byte_pack(op, ec >> 8);
 163				op = hex_byte_pack(op, ec);
 164				len -= 5;
 165			} else {
 166				*op++ = '?';
 167				len--;
 168			}
 169		}
 170	}
 171
 172	if (unlikely(*ip)) {
 173		fat_msg(sb, KERN_WARNING,
 174			"filename was truncated while converting.");
 175	}
 176
 177	*op = 0;
 178	return op - ascii;
 179}
 180
 181static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
 182				unsigned char *buf, int size)
 183{
 184	struct msdos_sb_info *sbi = MSDOS_SB(sb);
 185	if (sbi->options.utf8)
 186		return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
 187				UTF16_HOST_ENDIAN, buf, size);
 188	else
 189		return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
 190}
 191
 192static inline int
 193fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
 194{
 195	int charlen;
 196
 197	charlen = t->char2uni(c, clen, uni);
 198	if (charlen < 0) {
 199		*uni = 0x003f;	/* a question mark */
 200		charlen = 1;
 201	}
 202	return charlen;
 203}
 204
 205static inline int
 206fat_short2lower_uni(struct nls_table *t, unsigned char *c,
 207		    int clen, wchar_t *uni)
 208{
 209	int charlen;
 210	wchar_t wc;
 211
 212	charlen = t->char2uni(c, clen, &wc);
 213	if (charlen < 0) {
 214		*uni = 0x003f;	/* a question mark */
 215		charlen = 1;
 216	} else if (charlen <= 1) {
 217		unsigned char nc = t->charset2lower[*c];
 218
 219		if (!nc)
 220			nc = *c;
 221
 222		charlen = t->char2uni(&nc, 1, uni);
 223		if (charlen < 0) {
 224			*uni = 0x003f;	/* a question mark */
 225			charlen = 1;
 226		}
 227	} else
 228		*uni = wc;
 229
 230	return charlen;
 231}
 232
 233static inline int
 234fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
 235		  wchar_t *uni_buf, unsigned short opt, int lower)
 236{
 237	int len = 0;
 238
 239	if (opt & VFAT_SFN_DISPLAY_LOWER)
 240		len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 241	else if (opt & VFAT_SFN_DISPLAY_WIN95)
 242		len = fat_short2uni(nls, buf, buf_size, uni_buf);
 243	else if (opt & VFAT_SFN_DISPLAY_WINNT) {
 244		if (lower)
 245			len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 246		else
 247			len = fat_short2uni(nls, buf, buf_size, uni_buf);
 248	} else
 249		len = fat_short2uni(nls, buf, buf_size, uni_buf);
 250
 251	return len;
 252}
 253
 254static inline int fat_name_match(struct msdos_sb_info *sbi,
 255				 const unsigned char *a, int a_len,
 256				 const unsigned char *b, int b_len)
 257{
 258	if (a_len != b_len)
 259		return 0;
 260
 261	if (sbi->options.name_check != 's')
 262		return !nls_strnicmp(sbi->nls_io, a, b, a_len);
 263	else
 264		return !memcmp(a, b, a_len);
 265}
 266
 267enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
 268
 269/**
 270 * fat_parse_long - Parse extended directory entry.
 271 *
 272 * This function returns zero on success, negative value on error, or one of
 273 * the following:
 274 *
 275 * %PARSE_INVALID - Directory entry is invalid.
 276 * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
 277 * %PARSE_EOF - Directory has no more entries.
 278 */
 279static int fat_parse_long(struct inode *dir, loff_t *pos,
 280			  struct buffer_head **bh, struct msdos_dir_entry **de,
 281			  wchar_t **unicode, unsigned char *nr_slots)
 282{
 283	struct msdos_dir_slot *ds;
 284	unsigned char id, slot, slots, alias_checksum;
 285
 286	if (!*unicode) {
 287		*unicode = __getname();
 288		if (!*unicode) {
 289			brelse(*bh);
 290			return -ENOMEM;
 291		}
 292	}
 293parse_long:
 294	slots = 0;
 295	ds = (struct msdos_dir_slot *)*de;
 296	id = ds->id;
 297	if (!(id & 0x40))
 298		return PARSE_INVALID;
 299	slots = id & ~0x40;
 300	if (slots > 20 || !slots)	/* ceil(256 * 2 / 26) */
 301		return PARSE_INVALID;
 302	*nr_slots = slots;
 303	alias_checksum = ds->alias_checksum;
 304
 305	slot = slots;
 306	while (1) {
 307		int offset;
 308
 309		slot--;
 310		offset = slot * 13;
 311		fat16_towchar(*unicode + offset, ds->name0_4, 5);
 312		fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
 313		fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
 314
 315		if (ds->id & 0x40)
 316			(*unicode)[offset + 13] = 0;
 317		if (fat_get_entry(dir, pos, bh, de) < 0)
 318			return PARSE_EOF;
 319		if (slot == 0)
 320			break;
 321		ds = (struct msdos_dir_slot *)*de;
 322		if (ds->attr != ATTR_EXT)
 323			return PARSE_NOT_LONGNAME;
 324		if ((ds->id & ~0x40) != slot)
 325			goto parse_long;
 326		if (ds->alias_checksum != alias_checksum)
 327			goto parse_long;
 328	}
 329	if ((*de)->name[0] == DELETED_FLAG)
 330		return PARSE_INVALID;
 331	if ((*de)->attr == ATTR_EXT)
 332		goto parse_long;
 333	if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
 334		return PARSE_INVALID;
 335	if (fat_checksum((*de)->name) != alias_checksum)
 336		*nr_slots = 0;
 337
 338	return 0;
 339}
 340
 341/**
 342 * fat_parse_short - Parse MS-DOS (short) directory entry.
 343 * @sb:		superblock
 344 * @de:		directory entry to parse
 345 * @name:	FAT_MAX_SHORT_SIZE array in which to place extracted name
 346 * @dot_hidden:	Nonzero == prepend '.' to names with ATTR_HIDDEN
 347 *
 348 * Returns the number of characters extracted into 'name'.
 349 */
 350static int fat_parse_short(struct super_block *sb,
 351			   const struct msdos_dir_entry *de,
 352			   unsigned char *name, int dot_hidden)
 353{
 354	const struct msdos_sb_info *sbi = MSDOS_SB(sb);
 355	int isvfat = sbi->options.isvfat;
 356	int nocase = sbi->options.nocase;
 357	unsigned short opt_shortname = sbi->options.shortname;
 358	struct nls_table *nls_disk = sbi->nls_disk;
 359	wchar_t uni_name[14];
 360	unsigned char c, work[MSDOS_NAME];
 361	unsigned char *ptname = name;
 362	int chi, chl, i, j, k;
 363	int dotoffset = 0;
 364	int name_len = 0, uni_len = 0;
 365
 366	if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) {
 367		*ptname++ = '.';
 368		dotoffset = 1;
 369	}
 370
 371	memcpy(work, de->name, sizeof(work));
 372	/* see namei.c, msdos_format_name */
 373	if (work[0] == 0x05)
 374		work[0] = 0xE5;
 375
 376	/* Filename */
 377	for (i = 0, j = 0; i < 8;) {
 378		c = work[i];
 379		if (!c)
 380			break;
 381		chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
 382					&uni_name[j++], opt_shortname,
 383					de->lcase & CASE_LOWER_BASE);
 384		if (chl <= 1) {
 385			if (!isvfat)
 386				ptname[i] = nocase ? c : fat_tolower(c);
 387			i++;
 388			if (c != ' ') {
 389				name_len = i;
 390				uni_len  = j;
 391			}
 392		} else {
 393			uni_len = j;
 394			if (isvfat)
 395				i += min(chl, 8-i);
 396			else {
 397				for (chi = 0; chi < chl && i < 8; chi++, i++)
 398					ptname[i] = work[i];
 399			}
 400			if (chl)
 401				name_len = i;
 402		}
 403	}
 404
 405	i = name_len;
 406	j = uni_len;
 407	fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);
 408	if (!isvfat)
 409		ptname[i] = '.';
 410	i++;
 411
 412	/* Extension */
 413	for (k = 8; k < MSDOS_NAME;) {
 414		c = work[k];
 415		if (!c)
 416			break;
 417		chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,
 418					&uni_name[j++], opt_shortname,
 419					de->lcase & CASE_LOWER_EXT);
 420		if (chl <= 1) {
 421			k++;
 422			if (!isvfat)
 423				ptname[i] = nocase ? c : fat_tolower(c);
 424			i++;
 425			if (c != ' ') {
 426				name_len = i;
 427				uni_len  = j;
 428			}
 429		} else {
 430			uni_len = j;
 431			if (isvfat) {
 432				int offset = min(chl, MSDOS_NAME-k);
 433				k += offset;
 434				i += offset;
 435			} else {
 436				for (chi = 0; chi < chl && k < MSDOS_NAME;
 437				     chi++, i++, k++) {
 438						ptname[i] = work[k];
 439				}
 440			}
 441			if (chl)
 442				name_len = i;
 443		}
 444	}
 445
 446	if (name_len > 0) {
 447		name_len += dotoffset;
 448
 449		if (sbi->options.isvfat) {
 450			uni_name[uni_len] = 0x0000;
 451			name_len = fat_uni_to_x8(sb, uni_name, name,
 452						 FAT_MAX_SHORT_SIZE);
 453		}
 454	}
 455
 456	return name_len;
 457}
 458
 459/*
 460 * Return values: negative -> error/not found, 0 -> found.
 461 */
 462int fat_search_long(struct inode *inode, const unsigned char *name,
 463		    int name_len, struct fat_slot_info *sinfo)
 464{
 465	struct super_block *sb = inode->i_sb;
 466	struct msdos_sb_info *sbi = MSDOS_SB(sb);
 467	struct buffer_head *bh = NULL;
 468	struct msdos_dir_entry *de;
 469	unsigned char nr_slots;
 470	wchar_t *unicode = NULL;
 471	unsigned char bufname[FAT_MAX_SHORT_SIZE];
 472	loff_t cpos = 0;
 473	int err, len;
 474
 475	err = -ENOENT;
 476	while (1) {
 477		if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 478			goto end_of_dir;
 479parse_record:
 480		nr_slots = 0;
 481		if (de->name[0] == DELETED_FLAG)
 482			continue;
 483		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 484			continue;
 485		if (de->attr != ATTR_EXT && IS_FREE(de->name))
 486			continue;
 487		if (de->attr == ATTR_EXT) {
 488			int status = fat_parse_long(inode, &cpos, &bh, &de,
 489						    &unicode, &nr_slots);
 490			if (status < 0) {
 491				err = status;
 492				goto end_of_dir;
 493			} else if (status == PARSE_INVALID)
 494				continue;
 495			else if (status == PARSE_NOT_LONGNAME)
 496				goto parse_record;
 497			else if (status == PARSE_EOF)
 498				goto end_of_dir;
 499		}
 500
 501		/* Never prepend '.' to hidden files here.
 502		 * That is done only for msdos mounts (and only when
 503		 * 'dotsOK=yes'); if we are executing here, it is in the
 504		 * context of a vfat mount.
 505		 */
 506		len = fat_parse_short(sb, de, bufname, 0);
 507		if (len == 0)
 508			continue;
 509
 510		/* Compare shortname */
 511		if (fat_name_match(sbi, name, name_len, bufname, len))
 512			goto found;
 513
 514		if (nr_slots) {
 515			void *longname = unicode + FAT_MAX_UNI_CHARS;
 516			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 517
 518			/* Compare longname */
 519			len = fat_uni_to_x8(sb, unicode, longname, size);
 520			if (fat_name_match(sbi, name, name_len, longname, len))
 521				goto found;
 522		}
 523	}
 524
 525found:
 526	nr_slots++;	/* include the de */
 527	sinfo->slot_off = cpos - nr_slots * sizeof(*de);
 528	sinfo->nr_slots = nr_slots;
 529	sinfo->de = de;
 530	sinfo->bh = bh;
 531	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 532	err = 0;
 533end_of_dir:
 534	if (unicode)
 535		__putname(unicode);
 536
 537	return err;
 538}
 539EXPORT_SYMBOL_GPL(fat_search_long);
 540
 541struct fat_ioctl_filldir_callback {
 542	struct dir_context ctx;
 543	void __user *dirent;
 544	int result;
 545	/* for dir ioctl */
 546	const char *longname;
 547	int long_len;
 548	const char *shortname;
 549	int short_len;
 550};
 551
 552static int __fat_readdir(struct inode *inode, struct file *file,
 553			 struct dir_context *ctx, int short_only,
 554			 struct fat_ioctl_filldir_callback *both)
 555{
 556	struct super_block *sb = inode->i_sb;
 557	struct msdos_sb_info *sbi = MSDOS_SB(sb);
 558	struct buffer_head *bh;
 559	struct msdos_dir_entry *de;
 560	unsigned char nr_slots;
 561	wchar_t *unicode = NULL;
 562	unsigned char bufname[FAT_MAX_SHORT_SIZE];
 563	int isvfat = sbi->options.isvfat;
 564	const char *fill_name = NULL;
 565	int fake_offset = 0;
 566	loff_t cpos;
 567	int short_len = 0, fill_len = 0;
 568	int ret = 0;
 569
 570	mutex_lock(&sbi->s_lock);
 571
 572	cpos = ctx->pos;
 573	/* Fake . and .. for the root directory. */
 574	if (inode->i_ino == MSDOS_ROOT_INO) {
 575		if (!dir_emit_dots(file, ctx))
 576			goto out;
 577		if (ctx->pos == 2) {
 578			fake_offset = 1;
 579			cpos = 0;
 580		}
 581	}
 582	if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
 583		ret = -ENOENT;
 584		goto out;
 585	}
 586
 587	bh = NULL;
 588get_new:
 589	if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 590		goto end_of_dir;
 591parse_record:
 592	nr_slots = 0;
 593	/*
 594	 * Check for long filename entry, but if short_only, we don't
 595	 * need to parse long filename.
 596	 */
 597	if (isvfat && !short_only) {
 598		if (de->name[0] == DELETED_FLAG)
 599			goto record_end;
 600		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 601			goto record_end;
 602		if (de->attr != ATTR_EXT && IS_FREE(de->name))
 603			goto record_end;
 604	} else {
 605		if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
 606			goto record_end;
 607	}
 608
 609	if (isvfat && de->attr == ATTR_EXT) {
 610		int status = fat_parse_long(inode, &cpos, &bh, &de,
 611					    &unicode, &nr_slots);
 612		if (status < 0) {
 613			bh = NULL;
 614			ret = status;
 615			goto end_of_dir;
 616		} else if (status == PARSE_INVALID)
 617			goto record_end;
 618		else if (status == PARSE_NOT_LONGNAME)
 619			goto parse_record;
 620		else if (status == PARSE_EOF)
 621			goto end_of_dir;
 622
 623		if (nr_slots) {
 624			void *longname = unicode + FAT_MAX_UNI_CHARS;
 625			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 626			int len = fat_uni_to_x8(sb, unicode, longname, size);
 627
 628			fill_name = longname;
 629			fill_len = len;
 630			/* !both && !short_only, so we don't need shortname. */
 631			if (!both)
 632				goto start_filldir;
 633
 634			short_len = fat_parse_short(sb, de, bufname,
 635						    sbi->options.dotsOK);
 636			if (short_len == 0)
 637				goto record_end;
 638			/* hack for fat_ioctl_filldir() */
 639			both->longname = fill_name;
 640			both->long_len = fill_len;
 641			both->shortname = bufname;
 642			both->short_len = short_len;
 643			fill_name = NULL;
 644			fill_len = 0;
 645			goto start_filldir;
 646		}
 647	}
 648
 649	short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);
 650	if (short_len == 0)
 651		goto record_end;
 652
 653	fill_name = bufname;
 654	fill_len = short_len;
 655
 656start_filldir:
 657	ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
 658	if (fake_offset && ctx->pos < 2)
 659		ctx->pos = 2;
 660
 661	if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) {
 662		if (!dir_emit_dot(file, ctx))
 663			goto fill_failed;
 664	} else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 665		if (!dir_emit_dotdot(file, ctx))
 666			goto fill_failed;
 667	} else {
 668		unsigned long inum;
 669		loff_t i_pos = fat_make_i_pos(sb, bh, de);
 670		struct inode *tmp = fat_iget(sb, i_pos);
 671		if (tmp) {
 672			inum = tmp->i_ino;
 673			iput(tmp);
 674		} else
 675			inum = iunique(sb, MSDOS_ROOT_INO);
 676		if (!dir_emit(ctx, fill_name, fill_len, inum,
 677			    (de->attr & ATTR_DIR) ? DT_DIR : DT_REG))
 678			goto fill_failed;
 679	}
 680
 681record_end:
 682	fake_offset = 0;
 683	ctx->pos = cpos;
 684	goto get_new;
 685
 686end_of_dir:
 687	if (fake_offset && cpos < 2)
 688		ctx->pos = 2;
 689	else
 690		ctx->pos = cpos;
 691fill_failed:
 692	brelse(bh);
 693	if (unicode)
 694		__putname(unicode);
 695out:
 696	mutex_unlock(&sbi->s_lock);
 697
 698	return ret;
 699}
 700
 701static int fat_readdir(struct file *file, struct dir_context *ctx)
 702{
 703	return __fat_readdir(file_inode(file), file, ctx, 0, NULL);
 704}
 705
 706#define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)			   \
 707static int func(struct dir_context *ctx, const char *name, int name_len,   \
 708			     loff_t offset, u64 ino, unsigned int d_type)  \
 709{									   \
 710	struct fat_ioctl_filldir_callback *buf =			   \
 711		container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \
 712	struct dirent_type __user *d1 = buf->dirent;			   \
 713	struct dirent_type __user *d2 = d1 + 1;				   \
 714									   \
 715	if (buf->result)						   \
 716		return -EINVAL;						   \
 717	buf->result++;							   \
 718									   \
 719	if (name != NULL) {						   \
 720		/* dirent has only short name */			   \
 721		if (name_len >= sizeof(d1->d_name))			   \
 722			name_len = sizeof(d1->d_name) - 1;		   \
 723									   \
 724		if (put_user(0, d2->d_name)			||	   \
 725		    put_user(0, &d2->d_reclen)			||	   \
 726		    copy_to_user(d1->d_name, name, name_len)	||	   \
 727		    put_user(0, d1->d_name + name_len)		||	   \
 728		    put_user(name_len, &d1->d_reclen))			   \
 729			goto efault;					   \
 730	} else {							   \
 731		/* dirent has short and long name */			   \
 732		const char *longname = buf->longname;			   \
 733		int long_len = buf->long_len;				   \
 734		const char *shortname = buf->shortname;			   \
 735		int short_len = buf->short_len;				   \
 736									   \
 737		if (long_len >= sizeof(d1->d_name))			   \
 738			long_len = sizeof(d1->d_name) - 1;		   \
 739		if (short_len >= sizeof(d1->d_name))			   \
 740			short_len = sizeof(d1->d_name) - 1;		   \
 741									   \
 742		if (copy_to_user(d2->d_name, longname, long_len)	|| \
 743		    put_user(0, d2->d_name + long_len)			|| \
 744		    put_user(long_len, &d2->d_reclen)			|| \
 745		    put_user(ino, &d2->d_ino)				|| \
 746		    put_user(offset, &d2->d_off)			|| \
 747		    copy_to_user(d1->d_name, shortname, short_len)	|| \
 748		    put_user(0, d1->d_name + short_len)			|| \
 749		    put_user(short_len, &d1->d_reclen))			   \
 750			goto efault;					   \
 751	}								   \
 752	return 0;							   \
 753efault:									   \
 754	buf->result = -EFAULT;						   \
 755	return -EFAULT;							   \
 756}
 757
 758FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
 759
 760static int fat_ioctl_readdir(struct inode *inode, struct file *file,
 761			     void __user *dirent, filldir_t filldir,
 762			     int short_only, int both)
 763{
 764	struct fat_ioctl_filldir_callback buf = {
 765		.ctx.actor = filldir,
 766		.dirent = dirent
 767	};
 768	int ret;
 769
 770	buf.dirent = dirent;
 771	buf.result = 0;
 772	inode_lock_shared(inode);
 773	buf.ctx.pos = file->f_pos;
 774	ret = -ENOENT;
 775	if (!IS_DEADDIR(inode)) {
 776		ret = __fat_readdir(inode, file, &buf.ctx,
 777				    short_only, both ? &buf : NULL);
 778		file->f_pos = buf.ctx.pos;
 779	}
 780	inode_unlock_shared(inode);
 781	if (ret >= 0)
 782		ret = buf.result;
 783	return ret;
 784}
 785
 786static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
 787			  unsigned long arg)
 788{
 789	struct inode *inode = file_inode(filp);
 790	struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
 791	int short_only, both;
 792
 793	switch (cmd) {
 794	case VFAT_IOCTL_READDIR_SHORT:
 795		short_only = 1;
 796		both = 0;
 797		break;
 798	case VFAT_IOCTL_READDIR_BOTH:
 799		short_only = 0;
 800		both = 1;
 801		break;
 802	default:
 803		return fat_generic_ioctl(filp, cmd, arg);
 804	}
 805
 806	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
 807		return -EFAULT;
 808	/*
 809	 * Yes, we don't need this put_user() absolutely. However old
 810	 * code didn't return the right value. So, app use this value,
 811	 * in order to check whether it is EOF.
 812	 */
 813	if (put_user(0, &d1->d_reclen))
 814		return -EFAULT;
 815
 816	return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
 817				 short_only, both);
 818}
 819
 820#ifdef CONFIG_COMPAT
 821#define	VFAT_IOCTL_READDIR_BOTH32	_IOR('r', 1, struct compat_dirent[2])
 822#define	VFAT_IOCTL_READDIR_SHORT32	_IOR('r', 2, struct compat_dirent[2])
 823
 824FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
 825
 826static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
 827				 unsigned long arg)
 828{
 829	struct inode *inode = file_inode(filp);
 830	struct compat_dirent __user *d1 = compat_ptr(arg);
 831	int short_only, both;
 832
 833	switch (cmd) {
 834	case VFAT_IOCTL_READDIR_SHORT32:
 835		short_only = 1;
 836		both = 0;
 837		break;
 838	case VFAT_IOCTL_READDIR_BOTH32:
 839		short_only = 0;
 840		both = 1;
 841		break;
 842	default:
 843		return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
 844	}
 845
 846	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
 847		return -EFAULT;
 848	/*
 849	 * Yes, we don't need this put_user() absolutely. However old
 850	 * code didn't return the right value. So, app use this value,
 851	 * in order to check whether it is EOF.
 852	 */
 853	if (put_user(0, &d1->d_reclen))
 854		return -EFAULT;
 855
 856	return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
 857				 short_only, both);
 858}
 859#endif /* CONFIG_COMPAT */
 860
 861const struct file_operations fat_dir_operations = {
 862	.llseek		= generic_file_llseek,
 863	.read		= generic_read_dir,
 864	.iterate_shared	= fat_readdir,
 865	.unlocked_ioctl	= fat_dir_ioctl,
 866#ifdef CONFIG_COMPAT
 867	.compat_ioctl	= fat_compat_dir_ioctl,
 868#endif
 869	.fsync		= fat_file_fsync,
 870};
 871
 872static int fat_get_short_entry(struct inode *dir, loff_t *pos,
 873			       struct buffer_head **bh,
 874			       struct msdos_dir_entry **de)
 875{
 876	while (fat_get_entry(dir, pos, bh, de) >= 0) {
 877		/* free entry or long name entry or volume label */
 878		if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
 879			return 0;
 880	}
 881	return -ENOENT;
 882}
 883
 884/*
 885 * The ".." entry can not provide the "struct fat_slot_info" information
 886 * for inode, nor a usable i_pos. So, this function provides some information
 887 * only.
 888 *
 889 * Since this function walks through the on-disk inodes within a directory,
 890 * callers are responsible for taking any locks necessary to prevent the
 891 * directory from changing.
 892 */
 893int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 894			 struct msdos_dir_entry **de)
 895{
 896	loff_t offset = 0;
 897
 898	*de = NULL;
 899	while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
 900		if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
 901			return 0;
 902	}
 903	return -ENOENT;
 904}
 905EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
 906
 907/* See if directory is empty */
 908int fat_dir_empty(struct inode *dir)
 909{
 910	struct buffer_head *bh;
 911	struct msdos_dir_entry *de;
 912	loff_t cpos;
 913	int result = 0;
 914
 915	bh = NULL;
 916	cpos = 0;
 917	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 918		if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
 919		    strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 920			result = -ENOTEMPTY;
 921			break;
 922		}
 923	}
 924	brelse(bh);
 925	return result;
 926}
 927EXPORT_SYMBOL_GPL(fat_dir_empty);
 928
 929/*
 930 * fat_subdirs counts the number of sub-directories of dir. It can be run
 931 * on directories being created.
 932 */
 933int fat_subdirs(struct inode *dir)
 934{
 935	struct buffer_head *bh;
 936	struct msdos_dir_entry *de;
 937	loff_t cpos;
 938	int count = 0;
 939
 940	bh = NULL;
 941	cpos = 0;
 942	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 943		if (de->attr & ATTR_DIR)
 944			count++;
 945	}
 946	brelse(bh);
 947	return count;
 948}
 949
 950/*
 951 * Scans a directory for a given file (name points to its formatted name).
 952 * Returns an error code or zero.
 953 */
 954int fat_scan(struct inode *dir, const unsigned char *name,
 955	     struct fat_slot_info *sinfo)
 956{
 957	struct super_block *sb = dir->i_sb;
 958
 959	sinfo->slot_off = 0;
 960	sinfo->bh = NULL;
 961	while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
 962				   &sinfo->de) >= 0) {
 963		if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
 964			sinfo->slot_off -= sizeof(*sinfo->de);
 965			sinfo->nr_slots = 1;
 966			sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 967			return 0;
 968		}
 969	}
 970	return -ENOENT;
 971}
 972EXPORT_SYMBOL_GPL(fat_scan);
 973
 974/*
 975 * Scans a directory for a given logstart.
 976 * Returns an error code or zero.
 977 */
 978int fat_scan_logstart(struct inode *dir, int i_logstart,
 979		      struct fat_slot_info *sinfo)
 980{
 981	struct super_block *sb = dir->i_sb;
 982
 983	sinfo->slot_off = 0;
 984	sinfo->bh = NULL;
 985	while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
 986				   &sinfo->de) >= 0) {
 987		if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) {
 988			sinfo->slot_off -= sizeof(*sinfo->de);
 989			sinfo->nr_slots = 1;
 990			sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 991			return 0;
 992		}
 993	}
 994	return -ENOENT;
 995}
 996
 997static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
 998{
 999	struct super_block *sb = dir->i_sb;
1000	struct buffer_head *bh;
1001	struct msdos_dir_entry *de, *endp;
1002	int err = 0, orig_slots;
1003
1004	while (nr_slots) {
1005		bh = NULL;
1006		if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
1007			err = -EIO;
1008			break;
1009		}
1010
1011		orig_slots = nr_slots;
1012		endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
1013		while (nr_slots && de < endp) {
1014			de->name[0] = DELETED_FLAG;
1015			de++;
1016			nr_slots--;
1017		}
1018		mark_buffer_dirty_inode(bh, dir);
1019		if (IS_DIRSYNC(dir))
1020			err = sync_dirty_buffer(bh);
1021		brelse(bh);
1022		if (err)
1023			break;
1024
1025		/* pos is *next* de's position, so this does `- sizeof(de)' */
1026		pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
1027	}
1028
1029	return err;
1030}
1031
1032int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
1033{
1034	struct super_block *sb = dir->i_sb;
1035	struct msdos_dir_entry *de;
1036	struct buffer_head *bh;
1037	int err = 0, nr_slots;
1038
1039	/*
1040	 * First stage: Remove the shortname. By this, the directory
1041	 * entry is removed.
1042	 */
1043	nr_slots = sinfo->nr_slots;
1044	de = sinfo->de;
1045	sinfo->de = NULL;
1046	bh = sinfo->bh;
1047	sinfo->bh = NULL;
1048	while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
1049		de->name[0] = DELETED_FLAG;
1050		de--;
1051		nr_slots--;
1052	}
1053	mark_buffer_dirty_inode(bh, dir);
1054	if (IS_DIRSYNC(dir))
1055		err = sync_dirty_buffer(bh);
1056	brelse(bh);
1057	if (err)
1058		return err;
1059	dir->i_version++;
1060
1061	if (nr_slots) {
1062		/*
1063		 * Second stage: remove the remaining longname slots.
1064		 * (This directory entry is already removed, and so return
1065		 * the success)
1066		 */
1067		err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1068		if (err) {
1069			fat_msg(sb, KERN_WARNING,
1070			       "Couldn't remove the long name slots");
1071		}
1072	}
1073
1074	dir->i_mtime = dir->i_atime = current_time(dir);
1075	if (IS_DIRSYNC(dir))
1076		(void)fat_sync_inode(dir);
1077	else
1078		mark_inode_dirty(dir);
1079
1080	return 0;
1081}
1082EXPORT_SYMBOL_GPL(fat_remove_entries);
1083
1084static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1085			      struct buffer_head **bhs, int nr_bhs)
1086{
1087	struct super_block *sb = dir->i_sb;
1088	sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1089	int err, i, n;
1090
1091	/* Zeroing the unused blocks on this cluster */
1092	blknr += nr_used;
1093	n = nr_used;
1094	while (blknr < last_blknr) {
1095		bhs[n] = sb_getblk(sb, blknr);
1096		if (!bhs[n]) {
1097			err = -ENOMEM;
1098			goto error;
1099		}
1100		memset(bhs[n]->b_data, 0, sb->s_blocksize);
1101		set_buffer_uptodate(bhs[n]);
1102		mark_buffer_dirty_inode(bhs[n], dir);
1103
1104		n++;
1105		blknr++;
1106		if (n == nr_bhs) {
1107			if (IS_DIRSYNC(dir)) {
1108				err = fat_sync_bhs(bhs, n);
1109				if (err)
1110					goto error;
1111			}
1112			for (i = 0; i < n; i++)
1113				brelse(bhs[i]);
1114			n = 0;
1115		}
1116	}
1117	if (IS_DIRSYNC(dir)) {
1118		err = fat_sync_bhs(bhs, n);
1119		if (err)
1120			goto error;
1121	}
1122	for (i = 0; i < n; i++)
1123		brelse(bhs[i]);
1124
1125	return 0;
1126
1127error:
1128	for (i = 0; i < n; i++)
1129		bforget(bhs[i]);
1130	return err;
1131}
1132
1133int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1134{
1135	struct super_block *sb = dir->i_sb;
1136	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1137	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1138	struct msdos_dir_entry *de;
1139	sector_t blknr;
1140	__le16 date, time;
1141	u8 time_cs;
1142	int err, cluster;
1143
1144	err = fat_alloc_clusters(dir, &cluster, 1);
1145	if (err)
1146		goto error;
1147
1148	blknr = fat_clus_to_blknr(sbi, cluster);
1149	bhs[0] = sb_getblk(sb, blknr);
1150	if (!bhs[0]) {
1151		err = -ENOMEM;
1152		goto error_free;
1153	}
1154
1155	fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1156
1157	de = (struct msdos_dir_entry *)bhs[0]->b_data;
1158	/* filling the new directory slots ("." and ".." entries) */
1159	memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1160	memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1161	de->attr = de[1].attr = ATTR_DIR;
1162	de[0].lcase = de[1].lcase = 0;
1163	de[0].time = de[1].time = time;
1164	de[0].date = de[1].date = date;
1165	if (sbi->options.isvfat) {
1166		/* extra timestamps */
1167		de[0].ctime = de[1].ctime = time;
1168		de[0].ctime_cs = de[1].ctime_cs = time_cs;
1169		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1170	} else {
1171		de[0].ctime = de[1].ctime = 0;
1172		de[0].ctime_cs = de[1].ctime_cs = 0;
1173		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1174	}
1175	fat_set_start(&de[0], cluster);
1176	fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
1177	de[0].size = de[1].size = 0;
1178	memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1179	set_buffer_uptodate(bhs[0]);
1180	mark_buffer_dirty_inode(bhs[0], dir);
1181
1182	err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1183	if (err)
1184		goto error_free;
1185
1186	return cluster;
1187
1188error_free:
1189	fat_free_clusters(dir, cluster);
1190error:
1191	return err;
1192}
1193EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1194
1195static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1196			       int *nr_cluster, struct msdos_dir_entry **de,
1197			       struct buffer_head **bh, loff_t *i_pos)
1198{
1199	struct super_block *sb = dir->i_sb;
1200	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1201	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1202	sector_t blknr, start_blknr, last_blknr;
1203	unsigned long size, copy;
1204	int err, i, n, offset, cluster[2];
1205
1206	/*
1207	 * The minimum cluster size is 512bytes, and maximum entry
1208	 * size is 32*slots (672bytes).  So, iff the cluster size is
1209	 * 512bytes, we may need two clusters.
1210	 */
1211	size = nr_slots * sizeof(struct msdos_dir_entry);
1212	*nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1213	BUG_ON(*nr_cluster > 2);
1214
1215	err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1216	if (err)
1217		goto error;
1218
1219	/*
1220	 * First stage: Fill the directory entry.  NOTE: This cluster
1221	 * is not referenced from any inode yet, so updates order is
1222	 * not important.
1223	 */
1224	i = n = copy = 0;
1225	do {
1226		start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1227		last_blknr = start_blknr + sbi->sec_per_clus;
1228		while (blknr < last_blknr) {
1229			bhs[n] = sb_getblk(sb, blknr);
1230			if (!bhs[n]) {
1231				err = -ENOMEM;
1232				goto error_nomem;
1233			}
1234
1235			/* fill the directory entry */
1236			copy = min(size, sb->s_blocksize);
1237			memcpy(bhs[n]->b_data, slots, copy);
1238			slots += copy;
1239			size -= copy;
1240			set_buffer_uptodate(bhs[n]);
1241			mark_buffer_dirty_inode(bhs[n], dir);
1242			if (!size)
1243				break;
1244			n++;
1245			blknr++;
1246		}
1247	} while (++i < *nr_cluster);
1248
1249	memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1250	offset = copy - sizeof(struct msdos_dir_entry);
1251	get_bh(bhs[n]);
1252	*bh = bhs[n];
1253	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1254	*i_pos = fat_make_i_pos(sb, *bh, *de);
1255
1256	/* Second stage: clear the rest of cluster, and write outs */
1257	err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1258	if (err)
1259		goto error_free;
1260
1261	return cluster[0];
1262
1263error_free:
1264	brelse(*bh);
1265	*bh = NULL;
1266	n = 0;
1267error_nomem:
1268	for (i = 0; i < n; i++)
1269		bforget(bhs[i]);
1270	fat_free_clusters(dir, cluster[0]);
1271error:
1272	return err;
1273}
1274
1275int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1276		    struct fat_slot_info *sinfo)
1277{
1278	struct super_block *sb = dir->i_sb;
1279	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1280	struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1281	struct msdos_dir_entry *uninitialized_var(de);
1282	int err, free_slots, i, nr_bhs;
1283	loff_t pos, i_pos;
1284
1285	sinfo->nr_slots = nr_slots;
1286
1287	/* First stage: search free directory entries */
1288	free_slots = nr_bhs = 0;
1289	bh = prev = NULL;
1290	pos = 0;
1291	err = -ENOSPC;
1292	while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1293		/* check the maximum size of directory */
1294		if (pos >= FAT_MAX_DIR_SIZE)
1295			goto error;
1296
1297		if (IS_FREE(de->name)) {
1298			if (prev != bh) {
1299				get_bh(bh);
1300				bhs[nr_bhs] = prev = bh;
1301				nr_bhs++;
1302			}
1303			free_slots++;
1304			if (free_slots == nr_slots)
1305				goto found;
1306		} else {
1307			for (i = 0; i < nr_bhs; i++)
1308				brelse(bhs[i]);
1309			prev = NULL;
1310			free_slots = nr_bhs = 0;
1311		}
1312	}
1313	if (dir->i_ino == MSDOS_ROOT_INO) {
1314		if (sbi->fat_bits != 32)
1315			goto error;
1316	} else if (MSDOS_I(dir)->i_start == 0) {
1317		fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1318		       MSDOS_I(dir)->i_pos);
1319		err = -EIO;
1320		goto error;
1321	}
1322
1323found:
1324	err = 0;
1325	pos -= free_slots * sizeof(*de);
1326	nr_slots -= free_slots;
1327	if (free_slots) {
1328		/*
1329		 * Second stage: filling the free entries with new entries.
1330		 * NOTE: If this slots has shortname, first, we write
1331		 * the long name slots, then write the short name.
1332		 */
1333		int size = free_slots * sizeof(*de);
1334		int offset = pos & (sb->s_blocksize - 1);
1335		int long_bhs = nr_bhs - (nr_slots == 0);
1336
1337		/* Fill the long name slots. */
1338		for (i = 0; i < long_bhs; i++) {
1339			int copy = min_t(int, sb->s_blocksize - offset, size);
1340			memcpy(bhs[i]->b_data + offset, slots, copy);
1341			mark_buffer_dirty_inode(bhs[i], dir);
1342			offset = 0;
1343			slots += copy;
1344			size -= copy;
1345		}
1346		if (long_bhs && IS_DIRSYNC(dir))
1347			err = fat_sync_bhs(bhs, long_bhs);
1348		if (!err && i < nr_bhs) {
1349			/* Fill the short name slot. */
1350			int copy = min_t(int, sb->s_blocksize - offset, size);
1351			memcpy(bhs[i]->b_data + offset, slots, copy);
1352			mark_buffer_dirty_inode(bhs[i], dir);
1353			if (IS_DIRSYNC(dir))
1354				err = sync_dirty_buffer(bhs[i]);
1355		}
1356		for (i = 0; i < nr_bhs; i++)
1357			brelse(bhs[i]);
1358		if (err)
1359			goto error_remove;
1360	}
1361
1362	if (nr_slots) {
1363		int cluster, nr_cluster;
1364
1365		/*
1366		 * Third stage: allocate the cluster for new entries.
1367		 * And initialize the cluster with new entries, then
1368		 * add the cluster to dir.
1369		 */
1370		cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1371					      &de, &bh, &i_pos);
1372		if (cluster < 0) {
1373			err = cluster;
1374			goto error_remove;
1375		}
1376		err = fat_chain_add(dir, cluster, nr_cluster);
1377		if (err) {
1378			fat_free_clusters(dir, cluster);
1379			goto error_remove;
1380		}
1381		if (dir->i_size & (sbi->cluster_size - 1)) {
1382			fat_fs_error(sb, "Odd directory size");
1383			dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1384				& ~((loff_t)sbi->cluster_size - 1);
1385		}
1386		dir->i_size += nr_cluster << sbi->cluster_bits;
1387		MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1388	}
1389	sinfo->slot_off = pos;
1390	sinfo->de = de;
1391	sinfo->bh = bh;
1392	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1393
1394	return 0;
1395
1396error:
1397	brelse(bh);
1398	for (i = 0; i < nr_bhs; i++)
1399		brelse(bhs[i]);
1400	return err;
1401
1402error_remove:
1403	brelse(bh);
1404	if (free_slots)
1405		__fat_remove_entries(dir, pos, free_slots);
1406	return err;
1407}
1408EXPORT_SYMBOL_GPL(fat_add_entries);