diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index 67c67604b8c85eaf154b0db61715439aee2c15fe..a4feb67b3e538ae14861b22f27ea769aac72a990 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -2178,6 +2178,9 @@ static int diNewExt(struct inomap * imap, struct iag * iagp, int extno)
 	/* get the ag and iag numbers for this iag.
 	 */
 	agno = BLKTOAG(le64_to_cpu(iagp->agstart), sbi);
+	if (agno >= MAXAG || agno < 0)
+		return -EIO;
+
 	iagno = le32_to_cpu(iagp->iagnum);
 
 	/* check if this is the last free extent within the
diff --git a/fs/jfs/jfs_mount.c b/fs/jfs/jfs_mount.c
index aa4ff7bcaff23dd8931de14fbd629467819772e0..55702b31ab3c41c8bf28460349b0b60fdbf5ec32 100644
--- a/fs/jfs/jfs_mount.c
+++ b/fs/jfs/jfs_mount.c
@@ -172,15 +172,15 @@ int jfs_mount(struct super_block *sb)
 	}
 	jfs_info("jfs_mount: ipimap:0x%p", ipimap);
 
-	/* map further access of per fileset inodes by the fileset inode */
-	sbi->ipimap = ipimap;
-
 	/* initialize fileset inode allocation map */
 	if ((rc = diMount(ipimap))) {
 		jfs_err("jfs_mount: diMount failed w/rc = %d", rc);
 		goto err_ipimap;
 	}
 
+	/* map further access of per fileset inodes by the fileset inode */
+	sbi->ipimap = ipimap;
+
 	return rc;
 
 	/*