fs/isofs/rock.c - kernel/msm-4.19 - Gitiles

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

 #include <linux/slab.h>
 #include <linux/pagemap.h>
 #include <linux/smp_lock.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() */


 /* This is a way of ensuring that we have something in the system
    use fields that is compatible with Rock Ridge */
 #define CHECK_SP(FAIL)	       			\
       if(rr->u.SP.magic[0] != 0xbe) FAIL;	\
       if(rr->u.SP.magic[1] != 0xef) FAIL;       \
       ISOFS_SB(inode->i_sb)->s_rock_offset=rr->u.SP.skip;
 /* We define a series of macros because each function must do exactly the
    same thing in certain places.  We use the macros to ensure that everything
    is done correctly */

 #define CONTINUE_DECLS \
   int cont_extent = 0, cont_offset = 0, cont_size = 0;   \
   void *buffer = NULL

 #define CHECK_CE	       			\
       {cont_extent = isonum_733(rr->u.CE.extent); \
       cont_offset = isonum_733(rr->u.CE.offset); \
       cont_size = isonum_733(rr->u.CE.size);}

 #define SETUP_ROCK_RIDGE(DE,CHR,LEN)	      		      	\
   {LEN= sizeof(struct iso_directory_record) + DE->name_len[0];	\
   if(LEN & 1) LEN++;						\
   CHR = ((unsigned char *) DE) + LEN;				\
   LEN = *((unsigned char *) DE) - LEN;                          \
   if (LEN<0) LEN=0;                                             \
   if (ISOFS_SB(inode->i_sb)->s_rock_offset!=-1)                \
   {                                                             \
      LEN-=ISOFS_SB(inode->i_sb)->s_rock_offset;                \
      CHR+=ISOFS_SB(inode->i_sb)->s_rock_offset;                \
      if (LEN<0) LEN=0;                                          \
   }                                                             \
 }

 #define MAYBE_CONTINUE(LABEL,DEV) \
   {if (buffer) { kfree(buffer); buffer = NULL; } \
   if (cont_extent){ \
     int block, offset, offset1; \
     struct buffer_head * pbh; \
     buffer = kmalloc(cont_size,GFP_KERNEL); \
     if (!buffer) goto out; \
     block = cont_extent; \
     offset = cont_offset; \
     offset1 = 0; \
     pbh = sb_bread(DEV->i_sb, block); \
     if(pbh){       \
       if (offset > pbh->b_size || offset + cont_size > pbh->b_size){	\
 	brelse(pbh); \
 	goto out; \
       } \
       memcpy(buffer + offset1, pbh->b_data + offset, cont_size - offset1); \
       brelse(pbh); \
       chr = (unsigned char *) buffer; \
       len = cont_size; \
       cont_extent = 0; \
       cont_size = 0; \
       cont_offset = 0; \
       goto LABEL; \
     }    \
     printk("Unable to read rock-ridge attributes\n");    \
   }}

 /* 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)
 {
   int len;
   unsigned char * chr;
   CONTINUE_DECLS;
   int retnamlen = 0, truncate=0;

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

   SETUP_ROCK_RIDGE(de, chr, len);
  repeat:
   {
     struct rock_ridge * rr;
     int sig;

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

       switch(sig){
       case SIG('R','R'):
 	if((rr->u.RR.flags[0] & RR_NM) == 0) goto out;
 	break;
       case SIG('S','P'):
 	CHECK_SP(goto out);
 	break;
       case SIG('C','E'):
 	CHECK_CE;
 	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'):
 	if (buffer) kfree(buffer);
 	return -1;
       default:
 	break;
       }
     }
   }
   MAYBE_CONTINUE(repeat,inode);
   if (buffer) kfree(buffer);
   return retnamlen; /* If 0, this file did not have a NM field */
  out:
   if(buffer) kfree(buffer);
   return 0;
 }

 static int
 parse_rock_ridge_inode_internal(struct iso_directory_record *de,
 				struct inode *inode, int regard_xa)
 {
   int len;
   unsigned char * chr;
   int symlink_len = 0;
   CONTINUE_DECLS;

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

   SETUP_ROCK_RIDGE(de, chr, len);
   if (regard_xa)
    {
      chr+=14;
      len-=14;
      if (len<0) len=0;
    }

  repeat:
   {
     int cnt, sig;
     struct inode * reloc;
     struct rock_ridge * rr;
     int rootflag;

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

       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'):
 	CHECK_SP(goto out);
 	break;
       case SIG('C','E'):
 	CHECK_CE;
 	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. */
 	cnt = 0; /* Rock ridge never appears on a High Sierra disk */
 	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 (!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'):
 	      if ( !ISOFS_SB(inode->i_sb)->s_nocompress ) {
 		      int algo;
 		      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 < PAGE_CACHE_SHIFT || 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;
       }
     }
   }
   MAYBE_CONTINUE(repeat,inode);
  out:
   if(buffer) kfree(buffer);
   return 0;
 }

 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);
 	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_inode;
 	CONTINUE_DECLS;
 	unsigned long block, offset;
 	int sig;
 	int len;
 	unsigned char *chr;
 	struct rock_ridge *rr;

 	if (!ISOFS_SB(inode->i_sb)->s_rock)
 		goto error;

 	block = ei->i_iget5_block;
 	lock_kernel();
 	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_inode = (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_inode, chr, len);

       repeat:
 	while (len > 2) { /* There may be one byte for padding somewhere */
 		rr = (struct rock_ridge *) chr;
 		if (rr->len < 3)
 			goto out;	/* Something got screwed up here */
 		sig = isonum_721(chr);
 		chr += rr->len;
 		len -= rr->len;
 		if (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'):
 			CHECK_SP(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 */
 			CHECK_CE;
 		default:
 			break;
 		}
 	}
 	MAYBE_CONTINUE(repeat, inode);
 	if (buffer)
 		kfree(buffer);

 	if (rpnt == link)
 		goto fail;
 	brelse(bh);
 	*rpnt = '\0';
 	unlock_kernel();
 	SetPageUptodate(page);
 	kunmap(page);
 	unlock_page(page);
 	return 0;

 	/* error exit from macro */
       out:
 	if (buffer)
 		kfree(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);
 	unlock_kernel();
       error:
 	SetPageError(page);
 	kunmap(page);
 	unlock_page(page);
 	return -EIO;
 }

 struct address_space_operations isofs_symlink_aops = {
 	.readpage	= rock_ridge_symlink_readpage
 };
	/*
	* linux/fs/isofs/rock.c
	*
	* (C) 1992, 1993 Eric Youngdale
	*
	* Rock Ridge Extensions to iso9660
	*/

	#include <linux/slab.h>
	#include <linux/pagemap.h>
	#include <linux/smp_lock.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() */


	/* This is a way of ensuring that we have something in the system
	use fields that is compatible with Rock Ridge */
	#define CHECK_SP(FAIL) \
	if(rr->u.SP.magic[0] != 0xbe) FAIL; \
	if(rr->u.SP.magic[1] != 0xef) FAIL; \
	ISOFS_SB(inode->i_sb)->s_rock_offset=rr->u.SP.skip;
	/* We define a series of macros because each function must do exactly the
	same thing in certain places. We use the macros to ensure that everything
	is done correctly */

	#define CONTINUE_DECLS \
	int cont_extent = 0, cont_offset = 0, cont_size = 0; \
	void *buffer = NULL

	#define CHECK_CE \
	{cont_extent = isonum_733(rr->u.CE.extent); \
	cont_offset = isonum_733(rr->u.CE.offset); \
	cont_size = isonum_733(rr->u.CE.size);}

	#define SETUP_ROCK_RIDGE(DE,CHR,LEN) \
	{LEN= sizeof(struct iso_directory_record) + DE->name_len[0]; \
	if(LEN & 1) LEN++; \
	CHR = ((unsigned char *) DE) + LEN; \
	LEN = ((unsigned char ) DE) - LEN; \
	if (LEN<0) LEN=0; \
	if (ISOFS_SB(inode->i_sb)->s_rock_offset!=-1) \
	{ \
	LEN-=ISOFS_SB(inode->i_sb)->s_rock_offset; \
	CHR+=ISOFS_SB(inode->i_sb)->s_rock_offset; \
	if (LEN<0) LEN=0; \
	} \
	}

	#define MAYBE_CONTINUE(LABEL,DEV) \
	{if (buffer) { kfree(buffer); buffer = NULL; } \
	if (cont_extent){ \
	int block, offset, offset1; \
	struct buffer_head * pbh; \
	buffer = kmalloc(cont_size,GFP_KERNEL); \
	if (!buffer) goto out; \
	block = cont_extent; \
	offset = cont_offset; \
	offset1 = 0; \
	pbh = sb_bread(DEV->i_sb, block); \
	if(pbh){ \
	if (offset > pbh->b_size \|\| offset + cont_size > pbh->b_size){ \
	brelse(pbh); \
	goto out; \
	} \
	memcpy(buffer + offset1, pbh->b_data + offset, cont_size - offset1); \
	brelse(pbh); \
	chr = (unsigned char *) buffer; \
	len = cont_size; \
	cont_extent = 0; \
	cont_size = 0; \
	cont_offset = 0; \
	goto LABEL; \
	} \
	printk("Unable to read rock-ridge attributes\n"); \
	}}

	/* 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)
	{
	int len;
	unsigned char * chr;
	CONTINUE_DECLS;
	int retnamlen = 0, truncate=0;

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

	SETUP_ROCK_RIDGE(de, chr, len);
	repeat:
	{
	struct rock_ridge * rr;
	int sig;

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

	switch(sig){
	case SIG('R','R'):
	if((rr->u.RR.flags[0] & RR_NM) == 0) goto out;
	break;
	case SIG('S','P'):
	CHECK_SP(goto out);
	break;
	case SIG('C','E'):
	CHECK_CE;
	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'):
	if (buffer) kfree(buffer);
	return -1;
	default:
	break;
	}
	}
	}
	MAYBE_CONTINUE(repeat,inode);
	if (buffer) kfree(buffer);
	return retnamlen; /* If 0, this file did not have a NM field */
	out:
	if(buffer) kfree(buffer);
	return 0;
	}

	static int
	parse_rock_ridge_inode_internal(struct iso_directory_record *de,
	struct inode *inode, int regard_xa)
	{
	int len;
	unsigned char * chr;
	int symlink_len = 0;
	CONTINUE_DECLS;

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

	SETUP_ROCK_RIDGE(de, chr, len);
	if (regard_xa)
	{
	chr+=14;
	len-=14;
	if (len<0) len=0;
	}

	repeat:
	{
	int cnt, sig;
	struct inode * reloc;
	struct rock_ridge * rr;
	int rootflag;

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

	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'):
	CHECK_SP(goto out);
	break;
	case SIG('C','E'):
	CHECK_CE;
	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. */
	cnt = 0; /* Rock ridge never appears on a High Sierra disk */
	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 (!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'):
	if ( !ISOFS_SB(inode->i_sb)->s_nocompress ) {
	int algo;
	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 < PAGE_CACHE_SHIFT \|\| 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;
	}
	}
	}
	MAYBE_CONTINUE(repeat,inode);
	out:
	if(buffer) kfree(buffer);
	return 0;
	}

	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);
	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_inode;
	CONTINUE_DECLS;
	unsigned long block, offset;
	int sig;
	int len;
	unsigned char *chr;
	struct rock_ridge *rr;

	if (!ISOFS_SB(inode->i_sb)->s_rock)
	goto error;

	block = ei->i_iget5_block;
	lock_kernel();
	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_inode = (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_inode, chr, len);

	repeat:
	while (len > 2) { /* There may be one byte for padding somewhere */
	rr = (struct rock_ridge *) chr;
	if (rr->len < 3)
	goto out; /* Something got screwed up here */
	sig = isonum_721(chr);
	chr += rr->len;
	len -= rr->len;
	if (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'):
	CHECK_SP(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 */
	CHECK_CE;
	default:
	break;
	}
	}
	MAYBE_CONTINUE(repeat, inode);
	if (buffer)
	kfree(buffer);

	if (rpnt == link)
	goto fail;
	brelse(bh);
	*rpnt = '\0';
	unlock_kernel();
	SetPageUptodate(page);
	kunmap(page);
	unlock_page(page);
	return 0;

	/* error exit from macro */
	out:
	if (buffer)
	kfree(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);
	unlock_kernel();
	error:
	SetPageError(page);
	kunmap(page);
	unlock_page(page);
	return -EIO;
	}

	struct address_space_operations isofs_symlink_aops = {
	.readpage = rock_ridge_symlink_readpage
	};