udf: Unify types in anchor block detection

When detecting last recorded block and from it derived anchor block
position, we were mixing unsigned long, u32, and sector_t types. Since
udf supports only 32-bit block numbers this is harmless but sometimes
makes things awkward. Convert everything to udf_pblk_t and also handle
the situation when block device size would not fit into udf_pblk_t.
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/lowlevel.c

@@ -45,7 +45,7 @@ unsigned int udf_get_last_session(struct super_block *sb)
 	return 0;
 }
 
-unsigned long udf_get_last_block(struct super_block *sb)
+udf_pblk_t udf_get_last_block(struct super_block *sb)
 {
 	struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk);
 	unsigned long lblock = 0;
@@ -54,8 +54,11 @@ unsigned long udf_get_last_block(struct super_block *sb)
 	 * The cdrom layer call failed or returned obviously bogus value?
 	 * Try using the device size...
 	 */
-	if (!cdi || cdrom_get_last_written(cdi, &lblock) || lblock == 0)
+	if (!cdi || cdrom_get_last_written(cdi, &lblock) || lblock == 0) {
+		if (sb_bdev_nr_blocks(sb) > ~(udf_pblk_t)0)
+			return 0;
 		lblock = sb_bdev_nr_blocks(sb);
+	}
 
 	if (lblock)
 		return lblock - 1;

fs/udf/super.c

@@ -1861,10 +1861,10 @@ static int udf_check_anchor_block(struct super_block *sb, sector_t block,
  * Returns < 0 on error, 0 on success. -EAGAIN is special - try next set
  * of anchors.
  */
-static int udf_scan_anchors(struct super_block *sb, sector_t *lastblock,
+static int udf_scan_anchors(struct super_block *sb, udf_pblk_t *lastblock,
 			    struct kernel_lb_addr *fileset)
 {
-	sector_t last[6];
+	udf_pblk_t last[6];
 	int i;
 	struct udf_sb_info *sbi = UDF_SB(sb);
 	int last_count = 0;

fs/udf/udfdecl.h

@@ -196,7 +196,7 @@ extern void udf_new_tag(char *, uint16_t, uint16_t, uint16_t, uint32_t, int);
 
 /* lowlevel.c */
 extern unsigned int udf_get_last_session(struct super_block *);
-extern unsigned long udf_get_last_block(struct super_block *);
+udf_pblk_t udf_get_last_block(struct super_block *);
 
 /* partition.c */
 extern uint32_t udf_get_pblock(struct super_block *, uint32_t, uint16_t,