diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 337836a0a170..b766b5c9c593 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -821,6 +821,8 @@ static int isofs_fill_super(struct super_block *s, struct fs_context *fc)
 	if (!sb_set_blocksize(s, orig_zonesize))
 		goto out_freesbi;
 
+	sbi->s_session_start = (sector_t)vol_desc_start <<
+				(ISOFS_BLOCK_BITS - s->s_blocksize_bits);
 	sbi->s_nls_iocharset = NULL;
 
 #ifdef CONFIG_JOLIET
diff --git a/fs/isofs/isofs.h b/fs/isofs/isofs.h
index dacb9cdae4fd..79ca0256843a 100644
--- a/fs/isofs/isofs.h
+++ b/fs/isofs/isofs.h
@@ -35,6 +35,8 @@ struct isofs_sb_info {
 	unsigned long s_firstdatazone;
 	unsigned long s_log_zone_size;
 	unsigned long s_max_size;
+	/* Session start in filesystem block units. */
+	sector_t s_session_start;
 	
 	int           s_rock_offset; /* offset of SUSP fields within SU area */
 	s32           s_sbsector;
diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c
index 2628f31bd3a5..84e0d764c210 100644
--- a/fs/isofs/rock.c
+++ b/fs/isofs/rock.c
@@ -9,6 +9,7 @@
 
 #include <linux/slab.h>
 #include <linux/pagemap.h>
+#include <linux/blkdev.h>
 
 #include "isofs.h"
 #include "rock.h"
@@ -84,6 +85,10 @@ static void init_rock_state(struct rock_state *rs, struct inode *inode)
  */
 static int rock_continue(struct rock_state *rs)
 {
+	struct super_block *sb = rs->inode->i_sb;
+	struct isofs_sb_info *sbi = ISOFS_SB(sb);
+	sector_t session_end = sbi->s_session_start +
+		((sector_t)sbi->s_nzones << (ISOFS_BLOCK_BITS - sb->s_blocksize_bits));
 	int ret = 1;
 	int blocksize = 1 << rs->inode->i_blkbits;
 	const int min_de_size = offsetof(struct rock_ridge, u);
@@ -101,11 +106,13 @@ static int rock_continue(struct rock_state *rs)
 		goto out;
 	}
 
-	if ((unsigned)rs->cont_extent >= ISOFS_SB(rs->inode->i_sb)->s_nzones) {
+	if (rs->cont_extent &&
+	    (rs->cont_extent < sbi->s_session_start ||
+	     rs->cont_extent >= session_end)) {
 		printk(KERN_NOTICE "rock: corrupted directory entry. "
 			"extent=%u out of volume (nzones=%lu)\n",
 			(unsigned)rs->cont_extent,
-			ISOFS_SB(rs->inode->i_sb)->s_nzones);
+			sbi->s_nzones);
 		ret = -EIO;
 		goto out;
 	}