[net-next-2.6.git] / fs / isofs / rock.c

/*
 *  linux/fs/isofs/rock.c
 *
 *  (C) 1992, 1993  Eric Youngdale
 *
 *  Rock Ridge Extensions to iso9660
 */

#include <linux/slab.h>
#include <linux/pagemap.h>

#include "isofs.h"
#include "rock.h"

/*
 * These functions are designed to read the system areas of a directory record
 * and extract relevant information.  There are different functions provided
 * depending upon what information we need at the time.  One function fills
 * out an inode structure, a second one extracts a filename, a third one
 * returns a symbolic link name, and a fourth one returns the extent number
 * for the file.
 */

#define SIG(A,B) ((A) | ((B) << 8))	/* isonum_721() */

struct rock_state {
	void *buffer;
	unsigned char *chr;
	int len;
	int cont_size;
	int cont_extent;
	int cont_offset;
	struct inode *inode;
};

/*
 * This is a way of ensuring that we have something in the system
 * use fields that is compatible with Rock Ridge.  Return zero on success.
 */

static int check_sp(struct rock_ridge *rr, struct inode *inode)
{
	if (rr->u.SP.magic[0] != 0xbe)
		return -1;
	if (rr->u.SP.magic[1] != 0xef)
		return -1;
	ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip;
	return 0;
}

static void setup_rock_ridge(struct iso_directory_record *de,
			struct inode *inode, struct rock_state *rs)
{
	rs->len = sizeof(struct iso_directory_record) + de->name_len[0];
	if (rs->len & 1)
		(rs->len)++;
	rs->chr = (unsigned char *)de + rs->len;
	rs->len = *((unsigned char *)de) - rs->len;
	if (rs->len < 0)
		rs->len = 0;

	if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) {
		rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset;
		rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset;
		if (rs->len < 0)
			rs->len = 0;
	}
}

static void init_rock_state(struct rock_state *rs, struct inode *inode)
{
	memset(rs, 0, sizeof(*rs));
	rs->inode = inode;
}

/*
 * Returns 0 if the caller should continue scanning, 1 if the scan must end
 * and -ve on error.
 */
static int rock_continue(struct rock_state *rs)
{
	int ret = 1;
	int blocksize = 1 << rs->inode->i_blkbits;
	const int min_de_size = offsetof(struct rock_ridge, u);

	kfree(rs->buffer);
	rs->buffer = NULL;

	if ((unsigned)rs->cont_offset > blocksize - min_de_size ||
	    (unsigned)rs->cont_size > blocksize ||
	    (unsigned)(rs->cont_offset + rs->cont_size) > blocksize) {
		printk(KERN_NOTICE "rock: corrupted directory entry. "
			"extent=%d, offset=%d, size=%d\n",
			rs->cont_extent, rs->cont_offset, rs->cont_size);
		ret = -EIO;
		goto out;
	}

	if (rs->cont_extent) {
		struct buffer_head *bh;

		rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL);
		if (!rs->buffer) {
			ret = -ENOMEM;
			goto out;
		}
		ret = -EIO;
		bh = sb_bread(rs->inode->i_sb, rs->cont_extent);
		if (bh) {
			memcpy(rs->buffer, bh->b_data + rs->cont_offset,
					rs->cont_size);
			put_bh(bh);
			rs->chr = rs->buffer;
			rs->len = rs->cont_size;
			rs->cont_extent = 0;
			rs->cont_size = 0;
			rs->cont_offset = 0;
			return 0;
		}
		printk("Unable to read rock-ridge attributes\n");
	}
out:
	kfree(rs->buffer);
	rs->buffer = NULL;
	return ret;
}

/*
 * We think there's a record of type `sig' at rs->chr.  Parse the signature
 * and make sure that there's really room for a record of that type.
 */
static int rock_check_overflow(struct rock_state *rs, int sig)
{
	int len;

	switch (sig) {
	case SIG('S', 'P'):
		len = sizeof(struct SU_SP_s);
		break;
	case SIG('C', 'E'):
		len = sizeof(struct SU_CE_s);
		break;
	case SIG('E', 'R'):
		len = sizeof(struct SU_ER_s);
		break;
	case SIG('R', 'R'):
		len = sizeof(struct RR_RR_s);
		break;
	case SIG('P', 'X'):
		len = sizeof(struct RR_PX_s);
		break;
	case SIG('P', 'N'):
		len = sizeof(struct RR_PN_s);
		break;
	case SIG('S', 'L'):
		len = sizeof(struct RR_SL_s);
		break;
	case SIG('N', 'M'):
		len = sizeof(struct RR_NM_s);
		break;
	case SIG('C', 'L'):
		len = sizeof(struct RR_CL_s);
		break;
	case SIG('P', 'L'):
		len = sizeof(struct RR_PL_s);
		break;
	case SIG('T', 'F'):
		len = sizeof(struct RR_TF_s);
		break;
	case SIG('Z', 'F'):
		len = sizeof(struct RR_ZF_s);
		break;
	default:
		len = 0;
		break;
	}
	len += offsetof(struct rock_ridge, u);
	if (len > rs->len) {
		printk(KERN_NOTICE "rock: directory entry would overflow "
				"storage\n");
		printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n",
				sig, len, rs->len);
		return -EIO;
	}
	return 0;
}

/*
 * return length of name field; 0: not found, -1: to be ignored
 */
int get_rock_ridge_filename(struct iso_directory_record *de,
			    char *retname, struct inode *inode)
{
	struct rock_state rs;
	struct rock_ridge *rr;
	int sig;
	int retnamlen = 0;
	int truncate = 0;
	int ret = 0;

	if (!ISOFS_SB(inode->i_sb)->s_rock)
		return 0;
	*retname = 0;

	init_rock_state(&rs, inode);
	setup_rock_ridge(de, inode, &rs);
repeat:

	while (rs.len > 2) { /* There may be one byte for padding somewhere */
		rr = (struct rock_ridge *)rs.chr;
		/*
		 * Ignore rock ridge info if rr->len is out of range, but
		 * don't return -EIO because that would make the file
		 * invisible.
		 */
		if (rr->len < 3)
			goto out;	/* Something got screwed up here */
		sig = isonum_721(rs.chr);
		if (rock_check_overflow(&rs, sig))
			goto eio;
		rs.chr += rr->len;
		rs.len -= rr->len;
		/*
		 * As above, just ignore the rock ridge info if rr->len
		 * is bogus.
		 */
		if (rs.len < 0)
			goto out;	/* Something got screwed up here */

		switch (sig) {
		case SIG('R', 'R'):
			if ((rr->u.RR.flags[0] & RR_NM) == 0)
				goto out;
			break;
		case SIG('S', 'P'):
			if (check_sp(rr, inode))
				goto out;
			break;
		case SIG('C', 'E'):
			rs.cont_extent = isonum_733(rr->u.CE.extent);
			rs.cont_offset = isonum_733(rr->u.CE.offset);
			rs.cont_size = isonum_733(rr->u.CE.size);
			break;
		case SIG('N', 'M'):
			if (truncate)
				break;
			if (rr->len < 5)
				break;
			/*
			 * If the flags are 2 or 4, this indicates '.' or '..'.
			 * We don't want to do anything with this, because it
			 * screws up the code that calls us.  We don't really
			 * care anyways, since we can just use the non-RR
			 * name.
			 */
			if (rr->u.NM.flags & 6)
				break;

			if (rr->u.NM.flags & ~1) {
				printk("Unsupported NM flag settings (%d)\n",
					rr->u.NM.flags);
				break;
			}
			if ((strlen(retname) + rr->len - 5) >= 254) {
				truncate = 1;
				break;
			}
			strncat(retname, rr->u.NM.name, rr->len - 5);
			retnamlen += rr->len - 5;
			break;
		case SIG('R', 'E'):
			kfree(rs.buffer);
			return -1;
		default:
			break;
		}
	}
	ret = rock_continue(&rs);
	if (ret == 0)
		goto repeat;
	if (ret == 1)
		return retnamlen; /* If 0, this file did not have a NM field */
out:
	kfree(rs.buffer);
	return ret;
eio:
	ret = -EIO;
	goto out;
}

static int
parse_rock_ridge_inode_internal(struct iso_directory_record *de,
				struct inode *inode, int regard_xa)
{
	int symlink_len = 0;
	int cnt, sig;
	struct inode *reloc;
	struct rock_ridge *rr;
	int rootflag;
	struct rock_state rs;
	int ret = 0;

	if (!ISOFS_SB(inode->i_sb)->s_rock)
		return 0;

	init_rock_state(&rs, inode);
	setup_rock_ridge(de, inode, &rs);
	if (regard_xa) {
		rs.chr += 14;
		rs.len -= 14;
		if (rs.len < 0)
			rs.len = 0;
	}

repeat:
	while (rs.len > 2) { /* There may be one byte for padding somewhere */
		rr = (struct rock_ridge *)rs.chr;
		/*
		 * Ignore rock ridge info if rr->len is out of range, but
		 * don't return -EIO because that would make the file
		 * invisible.
		 */
		if (rr->len < 3)
			goto out;	/* Something got screwed up here */
		sig = isonum_721(rs.chr);
		if (rock_check_overflow(&rs, sig))
			goto eio;
		rs.chr += rr->len;
		rs.len -= rr->len;
		/*
		 * As above, just ignore the rock ridge info if rr->len
		 * is bogus.
		 */
		if (rs.len < 0)
			goto out;	/* Something got screwed up here */

		switch (sig) {
#ifndef CONFIG_ZISOFS		/* No flag for SF or ZF */
		case SIG('R', 'R'):
			if ((rr->u.RR.flags[0] &
			     (RR_PX | RR_TF | RR_SL | RR_CL)) == 0)
				goto out;
			break;
#endif
		case SIG('S', 'P'):
			if (check_sp(rr, inode))
				goto out;
			break;
		case SIG('C', 'E'):
			rs.cont_extent = isonum_733(rr->u.CE.extent);
			rs.cont_offset = isonum_733(rr->u.CE.offset);
			rs.cont_size = isonum_733(rr->u.CE.size);
			break;
		case SIG('E', 'R'):
			ISOFS_SB(inode->i_sb)->s_rock = 1;
			printk(KERN_DEBUG "ISO 9660 Extensions: ");
			{
				int p;
				for (p = 0; p < rr->u.ER.len_id; p++)
					printk("%c", rr->u.ER.data[p]);
			}
			printk("\n");
			break;
		case SIG('P', 'X'):
			inode->i_mode = isonum_733(rr->u.PX.mode);
			inode->i_nlink = isonum_733(rr->u.PX.n_links);
			inode->i_uid = isonum_733(rr->u.PX.uid);
			inode->i_gid = isonum_733(rr->u.PX.gid);
			break;
		case SIG('P', 'N'):
			{
				int high, low;
				high = isonum_733(rr->u.PN.dev_high);
				low = isonum_733(rr->u.PN.dev_low);
				/*
				 * The Rock Ridge standard specifies that if
				 * sizeof(dev_t) <= 4, then the high field is
				 * unused, and the device number is completely
				 * stored in the low field.  Some writers may
				 * ignore this subtlety,
				 * and as a result we test to see if the entire
				 * device number is
				 * stored in the low field, and use that.
				 */
				if ((low & ~0xff) && high == 0) {
					inode->i_rdev =
					    MKDEV(low >> 8, low & 0xff);
				} else {
					inode->i_rdev =
					    MKDEV(high, low);
				}
			}
			break;
		case SIG('T', 'F'):
			/*
			 * Some RRIP writers incorrectly place ctime in the
			 * TF_CREATE field. Try to handle this correctly for
			 * either case.
			 */
			/* Rock ridge never appears on a High Sierra disk */
			cnt = 0;
			if (rr->u.TF.flags & TF_CREATE) {
				inode->i_ctime.tv_sec =
				    iso_date(rr->u.TF.times[cnt++].time,
					     0);
				inode->i_ctime.tv_nsec = 0;
			}
			if (rr->u.TF.flags & TF_MODIFY) {
				inode->i_mtime.tv_sec =
				    iso_date(rr->u.TF.times[cnt++].time,
					     0);
				inode->i_mtime.tv_nsec = 0;
			}
			if (rr->u.TF.flags & TF_ACCESS) {
				inode->i_atime.tv_sec =
				    iso_date(rr->u.TF.times[cnt++].time,
					     0);
				inode->i_atime.tv_nsec = 0;
			}
			if (rr->u.TF.flags & TF_ATTRIBUTES) {
				inode->i_ctime.tv_sec =
				    iso_date(rr->u.TF.times[cnt++].time,
					     0);
				inode->i_ctime.tv_nsec = 0;
			}
			break;
		case SIG('S', 'L'):
			{
				int slen;
				struct SL_component *slp;
				struct SL_component *oldslp;
				slen = rr->len - 5;
				slp = &rr->u.SL.link;
				inode->i_size = symlink_len;
				while (slen > 1) {
					rootflag = 0;
					switch (slp->flags & ~1) {
					case 0:
						inode->i_size +=
						    slp->len;
						break;
					case 2:
						inode->i_size += 1;
						break;
					case 4:
						inode->i_size += 2;
						break;
					case 8:
						rootflag = 1;
						inode->i_size += 1;
						break;
					default:
						printk("Symlink component flag "
							"not implemented\n");
					}
					slen -= slp->len + 2;
					oldslp = slp;
					slp = (struct SL_component *)
						(((char *)slp) + slp->len + 2);

					if (slen < 2) {
						if (((rr->u.SL.
						      flags & 1) != 0)
						    &&
						    ((oldslp->
						      flags & 1) == 0))
							inode->i_size +=
							    1;
						break;
					}

					/*
					 * If this component record isn't
					 * continued, then append a '/'.
					 */
					if (!rootflag
					    && (oldslp->flags & 1) == 0)
						inode->i_size += 1;
				}
			}
			symlink_len = inode->i_size;
			break;
		case SIG('R', 'E'):
			printk(KERN_WARNING "Attempt to read inode for "
					"relocated directory\n");
			goto out;
		case SIG('C', 'L'):
			ISOFS_I(inode)->i_first_extent =
			    isonum_733(rr->u.CL.location);
			reloc =
			    isofs_iget(inode->i_sb,
				       ISOFS_I(inode)->i_first_extent,
				       0);
			if (IS_ERR(reloc)) {
				ret = PTR_ERR(reloc);
				goto out;
			}
			inode->i_mode = reloc->i_mode;
			inode->i_nlink = reloc->i_nlink;
			inode->i_uid = reloc->i_uid;
			inode->i_gid = reloc->i_gid;
			inode->i_rdev = reloc->i_rdev;
			inode->i_size = reloc->i_size;
			inode->i_blocks = reloc->i_blocks;
			inode->i_atime = reloc->i_atime;
			inode->i_ctime = reloc->i_ctime;
			inode->i_mtime = reloc->i_mtime;
			iput(reloc);
			break;
#ifdef CONFIG_ZISOFS
		case SIG('Z', 'F'): {
			int algo;

			if (ISOFS_SB(inode->i_sb)->s_nocompress)
				break;
			algo = isonum_721(rr->u.ZF.algorithm);
			if (algo == SIG('p', 'z')) {
				int block_shift =
					isonum_711(&rr->u.ZF.parms[1]);
				if (block_shift > 17) {
					printk(KERN_WARNING "isofs: "
						"Can't handle ZF block "
						"size of 2^%d\n",
						block_shift);
				} else {
					/*
					 * Note: we don't change
					 * i_blocks here
					 */
					ISOFS_I(inode)->i_file_format =
						isofs_file_compressed;
					/*
					 * Parameters to compression
					 * algorithm (header size,
					 * block size)
					 */
					ISOFS_I(inode)->i_format_parm[0] =
						isonum_711(&rr->u.ZF.parms[0]);
					ISOFS_I(inode)->i_format_parm[1] =
						isonum_711(&rr->u.ZF.parms[1]);
					inode->i_size =
					    isonum_733(rr->u.ZF.
						       real_size);
				}
			} else {
				printk(KERN_WARNING
				       "isofs: Unknown ZF compression "
						"algorithm: %c%c\n",
				       rr->u.ZF.algorithm[0],
				       rr->u.ZF.algorithm[1]);
			}
			break;
		}
#endif
		default:
			break;
		}
	}
	ret = rock_continue(&rs);
	if (ret == 0)
		goto repeat;
	if (ret == 1)
		ret = 0;
out:
	kfree(rs.buffer);
	return ret;
eio:
	ret = -EIO;
	goto out;
}

static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
{
	int slen;
	int rootflag;
	struct SL_component *oldslp;
	struct SL_component *slp;
	slen = rr->len - 5;
	slp = &rr->u.SL.link;
	while (slen > 1) {
		rootflag = 0;
		switch (slp->flags & ~1) {
		case 0:
			if (slp->len > plimit - rpnt)
				return NULL;
			memcpy(rpnt, slp->text, slp->len);
			rpnt += slp->len;
			break;
		case 2:
			if (rpnt >= plimit)
				return NULL;
			*rpnt++ = '.';
			break;
		case 4:
			if (2 > plimit - rpnt)
				return NULL;
			*rpnt++ = '.';
			*rpnt++ = '.';
			break;
		case 8:
			if (rpnt >= plimit)
				return NULL;
			rootflag = 1;
			*rpnt++ = '/';
			break;
		default:
			printk("Symlink component flag not implemented (%d)\n",
			       slp->flags);
		}
		slen -= slp->len + 2;
		oldslp = slp;
		slp = (struct SL_component *)((char *)slp + slp->len + 2);

		if (slen < 2) {
			/*
			 * If there is another SL record, and this component
			 * record isn't continued, then add a slash.
			 */
			if ((!rootflag) && (rr->u.SL.flags & 1) &&
			    !(oldslp->flags & 1)) {
				if (rpnt >= plimit)
					return NULL;
				*rpnt++ = '/';
			}
			break;
		}

		/*
		 * If this component record isn't continued, then append a '/'.
		 */
		if (!rootflag && !(oldslp->flags & 1)) {
			if (rpnt >= plimit)
				return NULL;
			*rpnt++ = '/';
		}
	}
	return rpnt;
}

int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode)
{
	int result = parse_rock_ridge_inode_internal(de, inode, 0);

	/*
	 * if rockridge flag was reset and we didn't look for attributes
	 * behind eventual XA attributes, have a look there
	 */
	if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
	    && (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
		result = parse_rock_ridge_inode_internal(de, inode, 14);
	}
	return result;
}

/*
 * readpage() for symlinks: reads symlink contents into the page and either
 * makes it uptodate and returns 0 or returns error (-EIO)
 */
static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
{
	struct inode *inode = page->mapping->host;
	struct iso_inode_info *ei = ISOFS_I(inode);
	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
	char *link = kmap(page);
	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
	struct buffer_head *bh;
	char *rpnt = link;
	unsigned char *pnt;
	struct iso_directory_record *raw_de;
	unsigned long block, offset;
	int sig;
	struct rock_ridge *rr;
	struct rock_state rs;
	int ret;

	if (!sbi->s_rock)
		goto error;

	init_rock_state(&rs, inode);
	block = ei->i_iget5_block;
	mutex_lock(&sbi->s_mutex);
	bh = sb_bread(inode->i_sb, block);
	if (!bh)
		goto out_noread;

	offset = ei->i_iget5_offset;
	pnt = (unsigned char *)bh->b_data + offset;

	raw_de = (struct iso_directory_record *)pnt;

	/*
	 * If we go past the end of the buffer, there is some sort of error.
	 */
	if (offset + *pnt > bufsize)
		goto out_bad_span;

	/*
	 * Now test for possible Rock Ridge extensions which will override
	 * some of these numbers in the inode structure.
	 */

	setup_rock_ridge(raw_de, inode, &rs);

repeat:
	while (rs.len > 2) { /* There may be one byte for padding somewhere */
		rr = (struct rock_ridge *)rs.chr;
		if (rr->len < 3)
			goto out;	/* Something got screwed up here */
		sig = isonum_721(rs.chr);
		if (rock_check_overflow(&rs, sig))
			goto out;
		rs.chr += rr->len;
		rs.len -= rr->len;
		if (rs.len < 0)
			goto out;	/* corrupted isofs */

		switch (sig) {
		case SIG('R', 'R'):
			if ((rr->u.RR.flags[0] & RR_SL) == 0)
				goto out;
			break;
		case SIG('S', 'P'):
			if (check_sp(rr, inode))
				goto out;
			break;
		case SIG('S', 'L'):
			rpnt = get_symlink_chunk(rpnt, rr,
						 link + (PAGE_SIZE - 1));
			if (rpnt == NULL)
				goto out;
			break;
		case SIG('C', 'E'):
			/* This tells is if there is a continuation record */
			rs.cont_extent = isonum_733(rr->u.CE.extent);
			rs.cont_offset = isonum_733(rr->u.CE.offset);
			rs.cont_size = isonum_733(rr->u.CE.size);
		default:
			break;
		}
	}
	ret = rock_continue(&rs);
	if (ret == 0)
		goto repeat;
	if (ret < 0)
		goto fail;

	if (rpnt == link)
		goto fail;
	brelse(bh);
	*rpnt = '\0';
	mutex_unlock(&sbi->s_mutex);
	SetPageUptodate(page);
	kunmap(page);
	unlock_page(page);
	return 0;

	/* error exit from macro */
out:
	kfree(rs.buffer);
	goto fail;
out_noread:
	printk("unable to read i-node block");
	goto fail;
out_bad_span:
	printk("symlink spans iso9660 blocks\n");
fail:
	brelse(bh);
	mutex_unlock(&sbi->s_mutex);
error:
	SetPageError(page);
	kunmap(page);
	unlock_page(page);
	return -EIO;
}

const struct address_space_operations isofs_symlink_aops = {
	.readpage = rock_ridge_symlink_readpage
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/isofs/rock.c
	3	*
	4	* (C) 1992, 1993 Eric Youngdale
	5	*
	6	* Rock Ridge Extensions to iso9660
	7	*/
	8
1da177e4 LT	9	#include <linux/slab.h>
1da177e4 LT	10	#include <linux/pagemap.h>
1da177e4	11
94f2f715	12	#include "isofs.h"
1da177e4 LT	13	#include "rock.h"
1da177e4 LT	14
7373909d AM	15	/*
7373909d AM	16	* These functions are designed to read the system areas of a directory record
1da177e4 LT	17	* and extract relevant information. There are different functions provided
	18	* depending upon what information we need at the time. One function fills
	19	* out an inode structure, a second one extracts a filename, a third one
	20	* returns a symbolic link name, and a fourth one returns the extent number
7373909d AM	21	* for the file.
7373909d AM	22	*/
1da177e4	23
1d372116	24	#define SIG(A,B) ((A) \| ((B) << 8)) /* isonum_721() */
1da177e4	25
ba40aaf0 AM	26	struct rock_state {
	27	void *buffer;
	28	unsigned char *chr;
	29	int len;
	30	int cont_size;
	31	int cont_extent;
	32	int cont_offset;
	33	struct inode *inode;
	34	};
	35
12121714 AM	36	/*
12121714 AM	37	* This is a way of ensuring that we have something in the system
7373909d	38	* use fields that is compatible with Rock Ridge. Return zero on success.
12121714 AM	39	*/
	40
	41	static int check_sp(struct rock_ridge rr, struct inode inode)
	42	{
	43	if (rr->u.SP.magic[0] != 0xbe)
	44	return -1;
	45	if (rr->u.SP.magic[1] != 0xef)
	46	return -1;
	47	ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip;
	48	return 0;
	49	}
	50
76ab07eb	51	static void setup_rock_ridge(struct iso_directory_record *de,
ba40aaf0	52	struct inode inode, struct rock_state rs)
76ab07eb	53	{
ba40aaf0 AM	54	rs->len = sizeof(struct iso_directory_record) + de->name_len[0];
	55	if (rs->len & 1)
	56	(rs->len)++;
	57	rs->chr = (unsigned char *)de + rs->len;
	58	rs->len = ((unsigned char )de) - rs->len;
	59	if (rs->len < 0)
	60	rs->len = 0;
76ab07eb AM	61
76ab07eb AM	62	if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) {
ba40aaf0 AM	63	rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset;
	64	rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset;
	65	if (rs->len < 0)
	66	rs->len = 0;
76ab07eb	67	}
1d372116	68	}
1da177e4	69
ba40aaf0 AM	70	static void init_rock_state(struct rock_state rs, struct inode inode)
	71	{
	72	memset(rs, 0, sizeof(*rs));
	73	rs->inode = inode;
	74	}
	75
	76	/*
	77	* Returns 0 if the caller should continue scanning, 1 if the scan must end
	78	* and -ve on error.
	79	*/
	80	static int rock_continue(struct rock_state *rs)
	81	{
	82	int ret = 1;
e595447e AM	83	int blocksize = 1 << rs->inode->i_blkbits;
e595447e AM	84	const int min_de_size = offsetof(struct rock_ridge, u);
ba40aaf0 AM	85
	86	kfree(rs->buffer);
	87	rs->buffer = NULL;
e595447e AM	88
	89	if ((unsigned)rs->cont_offset > blocksize - min_de_size \|\|
	90	(unsigned)rs->cont_size > blocksize \|\|
	91	(unsigned)(rs->cont_offset + rs->cont_size) > blocksize) {
	92	printk(KERN_NOTICE "rock: corrupted directory entry. "
	93	"extent=%d, offset=%d, size=%d\n",
	94	rs->cont_extent, rs->cont_offset, rs->cont_size);
	95	ret = -EIO;
	96	goto out;
	97	}
	98
ba40aaf0 AM	99	if (rs->cont_extent) {
	100	struct buffer_head *bh;
	101
	102	rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL);
	103	if (!rs->buffer) {
	104	ret = -ENOMEM;
	105	goto out;
	106	}
	107	ret = -EIO;
	108	bh = sb_bread(rs->inode->i_sb, rs->cont_extent);
	109	if (bh) {
	110	memcpy(rs->buffer, bh->b_data + rs->cont_offset,
	111	rs->cont_size);
	112	put_bh(bh);
	113	rs->chr = rs->buffer;
	114	rs->len = rs->cont_size;
	115	rs->cont_extent = 0;
	116	rs->cont_size = 0;
	117	rs->cont_offset = 0;
	118	return 0;
	119	}
	120	printk("Unable to read rock-ridge attributes\n");
	121	}
	122	out:
	123	kfree(rs->buffer);
	124	rs->buffer = NULL;
	125	return ret;
	126	}
1da177e4	127
f2966632 AM	128	/*
	129	* We think there's a record of type `sig' at rs->chr. Parse the signature
	130	* and make sure that there's really room for a record of that type.
	131	*/
	132	static int rock_check_overflow(struct rock_state *rs, int sig)
	133	{
	134	int len;
	135
	136	switch (sig) {
	137	case SIG('S', 'P'):
	138	len = sizeof(struct SU_SP_s);
	139	break;
	140	case SIG('C', 'E'):
	141	len = sizeof(struct SU_CE_s);
	142	break;
	143	case SIG('E', 'R'):
	144	len = sizeof(struct SU_ER_s);
	145	break;
	146	case SIG('R', 'R'):
	147	len = sizeof(struct RR_RR_s);
	148	break;
	149	case SIG('P', 'X'):
	150	len = sizeof(struct RR_PX_s);
	151	break;
	152	case SIG('P', 'N'):
	153	len = sizeof(struct RR_PN_s);
	154	break;
	155	case SIG('S', 'L'):
	156	len = sizeof(struct RR_SL_s);
	157	break;
	158	case SIG('N', 'M'):
	159	len = sizeof(struct RR_NM_s);
	160	break;
	161	case SIG('C', 'L'):
	162	len = sizeof(struct RR_CL_s);
	163	break;
	164	case SIG('P', 'L'):
	165	len = sizeof(struct RR_PL_s);
	166	break;
	167	case SIG('T', 'F'):
	168	len = sizeof(struct RR_TF_s);
	169	break;
	170	case SIG('Z', 'F'):
	171	len = sizeof(struct RR_ZF_s);
	172	break;
	173	default:
	174	len = 0;
	175	break;
	176	}
	177	len += offsetof(struct rock_ridge, u);
	178	if (len > rs->len) {
	179	printk(KERN_NOTICE "rock: directory entry would overflow "
	180	"storage\n");
	181	printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n",
	182	sig, len, rs->len);
	183	return -EIO;
	184	}
	185	return 0;
	186	}
	187
7373909d AM	188	/*
	189	* return length of name field; 0: not found, -1: to be ignored
	190	*/
1d372116 AM	191	int get_rock_ridge_filename(struct iso_directory_record *de,
1d372116 AM	192	char retname, struct inode inode)
1da177e4	193	{
ba40aaf0	194	struct rock_state rs;
7fa393a1 AM	195	struct rock_ridge *rr;
	196	int sig;
	197	int retnamlen = 0;
	198	int truncate = 0;
ba40aaf0	199	int ret = 0;
1da177e4	200
1d372116 AM	201	if (!ISOFS_SB(inode->i_sb)->s_rock)
	202	return 0;
	203	*retname = 0;
	204
ba40aaf0 AM	205	init_rock_state(&rs, inode);
ba40aaf0 AM	206	setup_rock_ridge(de, inode, &rs);
7fa393a1 AM	207	repeat:
7fa393a1 AM	208
ba40aaf0 AM	209	while (rs.len > 2) { /* There may be one byte for padding somewhere */
ba40aaf0 AM	210	rr = (struct rock_ridge *)rs.chr;
c0a1633b AG	211	/*
	212	* Ignore rock ridge info if rr->len is out of range, but
	213	* don't return -EIO because that would make the file
	214	* invisible.
	215	*/
7fa393a1 AM	216	if (rr->len < 3)
7fa393a1 AM	217	goto out; /* Something got screwed up here */
ba40aaf0	218	sig = isonum_721(rs.chr);
f2966632 AM	219	if (rock_check_overflow(&rs, sig))
f2966632 AM	220	goto eio;
ba40aaf0 AM	221	rs.chr += rr->len;
ba40aaf0 AM	222	rs.len -= rr->len;
c0a1633b AG	223	/*
	224	* As above, just ignore the rock ridge info if rr->len
	225	* is bogus.
	226	*/
ba40aaf0	227	if (rs.len < 0)
c0a1633b	228	goto out; /* Something got screwed up here */
7fa393a1 AM	229
	230	switch (sig) {
	231	case SIG('R', 'R'):
	232	if ((rr->u.RR.flags[0] & RR_NM) == 0)
	233	goto out;
	234	break;
	235	case SIG('S', 'P'):
12121714 AM	236	if (check_sp(rr, inode))
12121714 AM	237	goto out;
7fa393a1 AM	238	break;
7fa393a1 AM	239	case SIG('C', 'E'):
ba40aaf0 AM	240	rs.cont_extent = isonum_733(rr->u.CE.extent);
	241	rs.cont_offset = isonum_733(rr->u.CE.offset);
	242	rs.cont_size = isonum_733(rr->u.CE.size);
7fa393a1 AM	243	break;
	244	case SIG('N', 'M'):
	245	if (truncate)
1d372116	246	break;
7fa393a1	247	if (rr->len < 5)
1d372116	248	break;
7fa393a1 AM	249	/*
	250	* If the flags are 2 or 4, this indicates '.' or '..'.
	251	* We don't want to do anything with this, because it
	252	* screws up the code that calls us. We don't really
	253	* care anyways, since we can just use the non-RR
	254	* name.
	255	*/
	256	if (rr->u.NM.flags & 6)
1d372116	257	break;
1d372116	258
7fa393a1 AM	259	if (rr->u.NM.flags & ~1) {
	260	printk("Unsupported NM flag settings (%d)\n",
	261	rr->u.NM.flags);
1d372116	262	break;
7fa393a1 AM	263	}
	264	if ((strlen(retname) + rr->len - 5) >= 254) {
	265	truncate = 1;
1d372116 AM	266	break;
1d372116 AM	267	}
7fa393a1 AM	268	strncat(retname, rr->u.NM.name, rr->len - 5);
	269	retnamlen += rr->len - 5;
	270	break;
	271	case SIG('R', 'E'):
ba40aaf0	272	kfree(rs.buffer);
7fa393a1 AM	273	return -1;
	274	default:
	275	break;
1d372116	276	}
1da177e4	277	}
ba40aaf0 AM	278	ret = rock_continue(&rs);
	279	if (ret == 0)
	280	goto repeat;
	281	if (ret == 1)
	282	return retnamlen; /* If 0, this file did not have a NM field */
7fa393a1	283	out:
ba40aaf0 AM	284	kfree(rs.buffer);
ba40aaf0 AM	285	return ret;
f2966632 AM	286	eio:
	287	ret = -EIO;
	288	goto out;
1da177e4 LT	289	}
	290
	291	static int
	292	parse_rock_ridge_inode_internal(struct iso_directory_record *de,
	293	struct inode *inode, int regard_xa)
	294	{
1d372116	295	int symlink_len = 0;
7fa393a1 AM	296	int cnt, sig;
	297	struct inode *reloc;
	298	struct rock_ridge *rr;
	299	int rootflag;
ba40aaf0 AM	300	struct rock_state rs;
ba40aaf0 AM	301	int ret = 0;
1d372116 AM	302
	303	if (!ISOFS_SB(inode->i_sb)->s_rock)
	304	return 0;
	305
ba40aaf0 AM	306	init_rock_state(&rs, inode);
ba40aaf0 AM	307	setup_rock_ridge(de, inode, &rs);
1d372116	308	if (regard_xa) {
ba40aaf0 AM	309	rs.chr += 14;
	310	rs.len -= 14;
	311	if (rs.len < 0)
	312	rs.len = 0;
1d372116 AM	313	}
1d372116 AM	314
7fa393a1	315	repeat:
ba40aaf0 AM	316	while (rs.len > 2) { /* There may be one byte for padding somewhere */
ba40aaf0 AM	317	rr = (struct rock_ridge *)rs.chr;
c0a1633b AG	318	/*
	319	* Ignore rock ridge info if rr->len is out of range, but
	320	* don't return -EIO because that would make the file
	321	* invisible.
	322	*/
7fa393a1 AM	323	if (rr->len < 3)
7fa393a1 AM	324	goto out; /* Something got screwed up here */
ba40aaf0	325	sig = isonum_721(rs.chr);
f2966632 AM	326	if (rock_check_overflow(&rs, sig))
f2966632 AM	327	goto eio;
ba40aaf0 AM	328	rs.chr += rr->len;
ba40aaf0 AM	329	rs.len -= rr->len;
c0a1633b AG	330	/*
	331	* As above, just ignore the rock ridge info if rr->len
	332	* is bogus.
	333	*/
ba40aaf0	334	if (rs.len < 0)
c0a1633b	335	goto out; /* Something got screwed up here */
7fa393a1 AM	336
7fa393a1 AM	337	switch (sig) {
1da177e4	338	#ifndef CONFIG_ZISOFS /* No flag for SF or ZF */
7fa393a1 AM	339	case SIG('R', 'R'):
	340	if ((rr->u.RR.flags[0] &
	341	(RR_PX \| RR_TF \| RR_SL \| RR_CL)) == 0)
	342	goto out;
	343	break;
1da177e4	344	#endif
7fa393a1	345	case SIG('S', 'P'):
12121714 AM	346	if (check_sp(rr, inode))
12121714 AM	347	goto out;
7fa393a1 AM	348	break;
7fa393a1 AM	349	case SIG('C', 'E'):
ba40aaf0 AM	350	rs.cont_extent = isonum_733(rr->u.CE.extent);
	351	rs.cont_offset = isonum_733(rr->u.CE.offset);
	352	rs.cont_size = isonum_733(rr->u.CE.size);
7fa393a1 AM	353	break;
	354	case SIG('E', 'R'):
	355	ISOFS_SB(inode->i_sb)->s_rock = 1;
	356	printk(KERN_DEBUG "ISO 9660 Extensions: ");
	357	{
	358	int p;
	359	for (p = 0; p < rr->u.ER.len_id; p++)
	360	printk("%c", rr->u.ER.data[p]);
	361	}
	362	printk("\n");
	363	break;
	364	case SIG('P', 'X'):
	365	inode->i_mode = isonum_733(rr->u.PX.mode);
	366	inode->i_nlink = isonum_733(rr->u.PX.n_links);
	367	inode->i_uid = isonum_733(rr->u.PX.uid);
	368	inode->i_gid = isonum_733(rr->u.PX.gid);
	369	break;
	370	case SIG('P', 'N'):
	371	{
	372	int high, low;
	373	high = isonum_733(rr->u.PN.dev_high);
	374	low = isonum_733(rr->u.PN.dev_low);
	375	/*
	376	* The Rock Ridge standard specifies that if
	377	* sizeof(dev_t) <= 4, then the high field is
	378	* unused, and the device number is completely
	379	* stored in the low field. Some writers may
	380	* ignore this subtlety,
	381	* and as a result we test to see if the entire
	382	* device number is
	383	* stored in the low field, and use that.
	384	*/
	385	if ((low & ~0xff) && high == 0) {
	386	inode->i_rdev =
	387	MKDEV(low >> 8, low & 0xff);
	388	} else {
	389	inode->i_rdev =
	390	MKDEV(high, low);
1d372116	391	}
7fa393a1 AM	392	}
	393	break;
	394	case SIG('T', 'F'):
	395	/*
	396	* Some RRIP writers incorrectly place ctime in the
	397	* TF_CREATE field. Try to handle this correctly for
	398	* either case.
	399	*/
	400	/* Rock ridge never appears on a High Sierra disk */
	401	cnt = 0;
	402	if (rr->u.TF.flags & TF_CREATE) {
	403	inode->i_ctime.tv_sec =
	404	iso_date(rr->u.TF.times[cnt++].time,
	405	0);
	406	inode->i_ctime.tv_nsec = 0;
	407	}
	408	if (rr->u.TF.flags & TF_MODIFY) {
	409	inode->i_mtime.tv_sec =
	410	iso_date(rr->u.TF.times[cnt++].time,
	411	0);
	412	inode->i_mtime.tv_nsec = 0;
	413	}
	414	if (rr->u.TF.flags & TF_ACCESS) {
	415	inode->i_atime.tv_sec =
	416	iso_date(rr->u.TF.times[cnt++].time,
	417	0);
	418	inode->i_atime.tv_nsec = 0;
	419	}
	420	if (rr->u.TF.flags & TF_ATTRIBUTES) {
	421	inode->i_ctime.tv_sec =
	422	iso_date(rr->u.TF.times[cnt++].time,
	423	0);
	424	inode->i_ctime.tv_nsec = 0;
	425	}
	426	break;
	427	case SIG('S', 'L'):
	428	{
	429	int slen;
	430	struct SL_component *slp;
	431	struct SL_component *oldslp;
	432	slen = rr->len - 5;
	433	slp = &rr->u.SL.link;
	434	inode->i_size = symlink_len;
	435	while (slen > 1) {
	436	rootflag = 0;
	437	switch (slp->flags & ~1) {
	438	case 0:
	439	inode->i_size +=
	440	slp->len;
	441	break;
	442	case 2:
	443	inode->i_size += 1;
	444	break;
	445	case 4:
	446	inode->i_size += 2;
	447	break;
	448	case 8:
	449	rootflag = 1;
	450	inode->i_size += 1;
	451	break;
	452	default:
	453	printk("Symlink component flag "
	454	"not implemented\n");
1d372116	455	}
7fa393a1 AM	456	slen -= slp->len + 2;
	457	oldslp = slp;
	458	slp = (struct SL_component *)
	459	(((char *)slp) + slp->len + 2);
	460
	461	if (slen < 2) {
	462	if (((rr->u.SL.
	463	flags & 1) != 0)
	464	&&
	465	((oldslp->
	466	flags & 1) == 0))
1d372116	467	inode->i_size +=
7fa393a1 AM	468	1;
7fa393a1 AM	469	break;
1d372116	470	}
7fa393a1 AM	471
	472	/*
	473	* If this component record isn't
	474	* continued, then append a '/'.
	475	*/
	476	if (!rootflag
	477	&& (oldslp->flags & 1) == 0)
	478	inode->i_size += 1;
1d372116	479	}
7fa393a1 AM	480	}
	481	symlink_len = inode->i_size;
	482	break;
	483	case SIG('R', 'E'):
	484	printk(KERN_WARNING "Attempt to read inode for "
	485	"relocated directory\n");
	486	goto out;
	487	case SIG('C', 'L'):
	488	ISOFS_I(inode)->i_first_extent =
	489	isonum_733(rr->u.CL.location);
	490	reloc =
	491	isofs_iget(inode->i_sb,
	492	ISOFS_I(inode)->i_first_extent,
	493	0);
c4386c83 DH	494	if (IS_ERR(reloc)) {
c4386c83 DH	495	ret = PTR_ERR(reloc);
1d372116	496	goto out;
c4386c83	497	}
7fa393a1 AM	498	inode->i_mode = reloc->i_mode;
	499	inode->i_nlink = reloc->i_nlink;
	500	inode->i_uid = reloc->i_uid;
	501	inode->i_gid = reloc->i_gid;
	502	inode->i_rdev = reloc->i_rdev;
	503	inode->i_size = reloc->i_size;
	504	inode->i_blocks = reloc->i_blocks;
	505	inode->i_atime = reloc->i_atime;
	506	inode->i_ctime = reloc->i_ctime;
	507	inode->i_mtime = reloc->i_mtime;
	508	iput(reloc);
	509	break;
1da177e4	510	#ifdef CONFIG_ZISOFS
7fa393a1 AM	511	case SIG('Z', 'F'): {
	512	int algo;
	513
	514	if (ISOFS_SB(inode->i_sb)->s_nocompress)
1d372116	515	break;
7fa393a1 AM	516	algo = isonum_721(rr->u.ZF.algorithm);
	517	if (algo == SIG('p', 'z')) {
	518	int block_shift =
	519	isonum_711(&rr->u.ZF.parms[1]);
59bc0552	520	if (block_shift > 17) {
7fa393a1 AM	521	printk(KERN_WARNING "isofs: "
	522	"Can't handle ZF block "
	523	"size of 2^%d\n",
	524	block_shift);
	525	} else {
	526	/*
	527	* Note: we don't change
	528	* i_blocks here
	529	*/
	530	ISOFS_I(inode)->i_file_format =
	531	isofs_file_compressed;
	532	/*
	533	* Parameters to compression
	534	* algorithm (header size,
	535	* block size)
	536	*/
	537	ISOFS_I(inode)->i_format_parm[0] =
	538	isonum_711(&rr->u.ZF.parms[0]);
	539	ISOFS_I(inode)->i_format_parm[1] =
	540	isonum_711(&rr->u.ZF.parms[1]);
	541	inode->i_size =
	542	isonum_733(rr->u.ZF.
	543	real_size);
	544	}
	545	} else {
	546	printk(KERN_WARNING
	547	"isofs: Unknown ZF compression "
	548	"algorithm: %c%c\n",
	549	rr->u.ZF.algorithm[0],
	550	rr->u.ZF.algorithm[1]);
1d372116	551	}
7fa393a1 AM	552	break;
	553	}
	554	#endif
	555	default:
	556	break;
1d372116 AM	557	}
1d372116 AM	558	}
ba40aaf0 AM	559	ret = rock_continue(&rs);
	560	if (ret == 0)
	561	goto repeat;
	562	if (ret == 1)
	563	ret = 0;
7fa393a1	564	out:
ba40aaf0 AM	565	kfree(rs.buffer);
ba40aaf0 AM	566	return ret;
f2966632 AM	567	eio:
	568	ret = -EIO;
	569	goto out;
1da177e4 LT	570	}
	571
	572	static char get_symlink_chunk(char rpnt, struct rock_ridge rr, char plimit)
	573	{
	574	int slen;
	575	int rootflag;
	576	struct SL_component *oldslp;
	577	struct SL_component *slp;
	578	slen = rr->len - 5;
	579	slp = &rr->u.SL.link;
	580	while (slen > 1) {
	581	rootflag = 0;
	582	switch (slp->flags & ~1) {
	583	case 0:
	584	if (slp->len > plimit - rpnt)
	585	return NULL;
	586	memcpy(rpnt, slp->text, slp->len);
1d372116	587	rpnt += slp->len;
1da177e4 LT	588	break;
	589	case 2:
	590	if (rpnt >= plimit)
	591	return NULL;
1d372116	592	*rpnt++ = '.';
1da177e4 LT	593	break;
	594	case 4:
	595	if (2 > plimit - rpnt)
	596	return NULL;
1d372116 AM	597	*rpnt++ = '.';
1d372116 AM	598	*rpnt++ = '.';
1da177e4 LT	599	break;
	600	case 8:
	601	if (rpnt >= plimit)
	602	return NULL;
	603	rootflag = 1;
1d372116	604	*rpnt++ = '/';
1da177e4 LT	605	break;
	606	default:
	607	printk("Symlink component flag not implemented (%d)\n",
1d372116	608	slp->flags);
1da177e4 LT	609	}
	610	slen -= slp->len + 2;
	611	oldslp = slp;
1d372116	612	slp = (struct SL_component )((char )slp + slp->len + 2);
1da177e4 LT	613
	614	if (slen < 2) {
	615	/*
	616	* If there is another SL record, and this component
	617	* record isn't continued, then add a slash.
	618	*/
	619	if ((!rootflag) && (rr->u.SL.flags & 1) &&
	620	!(oldslp->flags & 1)) {
	621	if (rpnt >= plimit)
	622	return NULL;
1d372116	623	*rpnt++ = '/';
1da177e4 LT	624	}
	625	break;
	626	}
	627
	628	/*
	629	* If this component record isn't continued, then append a '/'.
	630	*/
	631	if (!rootflag && !(oldslp->flags & 1)) {
	632	if (rpnt >= plimit)
	633	return NULL;
1d372116	634	*rpnt++ = '/';
1da177e4 LT	635	}
	636	}
	637	return rpnt;
	638	}
	639
1d372116	640	int parse_rock_ridge_inode(struct iso_directory_record de, struct inode inode)
1da177e4	641	{
1d372116	642	int result = parse_rock_ridge_inode_internal(de, inode, 0);
7373909d AM	643
	644	/*
	645	* if rockridge flag was reset and we didn't look for attributes
	646	* behind eventual XA attributes, have a look there
	647	*/
1d372116 AM	648	if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
	649	&& (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
	650	result = parse_rock_ridge_inode_internal(de, inode, 14);
	651	}
	652	return result;
1da177e4 LT	653	}
1da177e4 LT	654
7373909d AM	655	/*
	656	* readpage() for symlinks: reads symlink contents into the page and either
	657	* makes it uptodate and returns 0 or returns error (-EIO)
	658	*/
1da177e4 LT	659	static int rock_ridge_symlink_readpage(struct file file, struct page page)
	660	{
	661	struct inode *inode = page->mapping->host;
1d372116	662	struct iso_inode_info *ei = ISOFS_I(inode);
4f819a78	663	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
1da177e4 LT	664	char *link = kmap(page);
	665	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
	666	struct buffer_head *bh;
	667	char *rpnt = link;
	668	unsigned char *pnt;
76ab07eb	669	struct iso_directory_record *raw_de;
1da177e4 LT	670	unsigned long block, offset;
1da177e4 LT	671	int sig;
1da177e4	672	struct rock_ridge *rr;
ba40aaf0 AM	673	struct rock_state rs;
ba40aaf0 AM	674	int ret;
1da177e4	675
4f819a78	676	if (!sbi->s_rock)
1da177e4 LT	677	goto error;
1da177e4 LT	678
ba40aaf0	679	init_rock_state(&rs, inode);
1da177e4	680	block = ei->i_iget5_block;
4f819a78	681	mutex_lock(&sbi->s_mutex);
1da177e4 LT	682	bh = sb_bread(inode->i_sb, block);
	683	if (!bh)
	684	goto out_noread;
	685
1d372116 AM	686	offset = ei->i_iget5_offset;
1d372116 AM	687	pnt = (unsigned char *)bh->b_data + offset;
1da177e4	688
76ab07eb	689	raw_de = (struct iso_directory_record *)pnt;
1da177e4 LT	690
	691	/*
	692	* If we go past the end of the buffer, there is some sort of error.
	693	*/
	694	if (offset + *pnt > bufsize)
	695	goto out_bad_span;
	696
7373909d AM	697	/*
	698	* Now test for possible Rock Ridge extensions which will override
	699	* some of these numbers in the inode structure.
	700	*/
1da177e4	701
ba40aaf0	702	setup_rock_ridge(raw_de, inode, &rs);
1da177e4	703
7fa393a1	704	repeat:
ba40aaf0 AM	705	while (rs.len > 2) { /* There may be one byte for padding somewhere */
ba40aaf0 AM	706	rr = (struct rock_ridge *)rs.chr;
1da177e4 LT	707	if (rr->len < 3)
1da177e4 LT	708	goto out; /* Something got screwed up here */
ba40aaf0	709	sig = isonum_721(rs.chr);
f2966632 AM	710	if (rock_check_overflow(&rs, sig))
f2966632 AM	711	goto out;
ba40aaf0 AM	712	rs.chr += rr->len;
	713	rs.len -= rr->len;
	714	if (rs.len < 0)
1da177e4 LT	715	goto out; /* corrupted isofs */
	716
	717	switch (sig) {
	718	case SIG('R', 'R'):
	719	if ((rr->u.RR.flags[0] & RR_SL) == 0)
	720	goto out;
	721	break;
	722	case SIG('S', 'P'):
12121714 AM	723	if (check_sp(rr, inode))
12121714 AM	724	goto out;
1da177e4 LT	725	break;
	726	case SIG('S', 'L'):
	727	rpnt = get_symlink_chunk(rpnt, rr,
	728	link + (PAGE_SIZE - 1));
	729	if (rpnt == NULL)
	730	goto out;
	731	break;
	732	case SIG('C', 'E'):
	733	/* This tells is if there is a continuation record */
ba40aaf0 AM	734	rs.cont_extent = isonum_733(rr->u.CE.extent);
	735	rs.cont_offset = isonum_733(rr->u.CE.offset);
	736	rs.cont_size = isonum_733(rr->u.CE.size);
1da177e4 LT	737	default:
	738	break;
	739	}
	740	}
ba40aaf0 AM	741	ret = rock_continue(&rs);
	742	if (ret == 0)
	743	goto repeat;
	744	if (ret < 0)
	745	goto fail;
1da177e4 LT	746
	747	if (rpnt == link)
	748	goto fail;
	749	brelse(bh);
	750	*rpnt = '\0';
4f819a78	751	mutex_unlock(&sbi->s_mutex);
1da177e4 LT	752	SetPageUptodate(page);
	753	kunmap(page);
	754	unlock_page(page);
	755	return 0;
	756
	757	/* error exit from macro */
7fa393a1	758	out:
ba40aaf0	759	kfree(rs.buffer);
1da177e4	760	goto fail;
7fa393a1	761	out_noread:
1da177e4 LT	762	printk("unable to read i-node block");
1da177e4 LT	763	goto fail;
7fa393a1	764	out_bad_span:
1da177e4	765	printk("symlink spans iso9660 blocks\n");
7fa393a1	766	fail:
1da177e4	767	brelse(bh);
4f819a78	768	mutex_unlock(&sbi->s_mutex);
7fa393a1	769	error:
1da177e4 LT	770	SetPageError(page);
	771	kunmap(page);
	772	unlock_page(page);
	773	return -EIO;
	774	}
	775
f5e54d6e	776	const struct address_space_operations isofs_symlink_aops = {
1d372116	777	.readpage = rock_ridge_symlink_readpage
1da177e4	778	};