[PATCH] device-mapper: Fixes for 64-bit sector_t.

[PATCH] device-mapper: Fixes for 64-bit sector_t.

[Alasdair G Kergon]

Fix some bugs in device-mapper handling of 64-bit values,
replacing dm_div_up() and dm_round_up() inlines with macros and
removing some avoidable divisions of 64-bit numbers.

The mirror region size is the granularity used to manage and monitor
the data copying, typically 512KB, so 32 bits (of sectors) should 
be plenty to hold this.

Taken together with the two earlier patches:
  "fix TB stripe data corruption" (a missing cast) and 
  "stripe_width should be sector_t",
I've now had 3 independent reports that this fixes device-mapper
for devices with large stripes.

Still awaiting test results for dm-crypt and dm-raid1.

Signed-Off-By: Alasdair G Kergon <agk@redhat.com>

--- diff/drivers/md/dm-crypt.c	2005-01-12 15:21:22.000000000 +0000
+++ source/drivers/md/dm-crypt.c	2005-01-28 15:30:22.000000000 +0000
@@ -329,7 +329,7 @@
                    struct bio *base_bio, unsigned int *bio_vec_idx)
 {
 	struct bio *bio;
-	unsigned int nr_iovecs = dm_div_up(size, PAGE_SIZE);
+	unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	int gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
 	unsigned long flags = current->flags;
 	unsigned int i;
--- diff/drivers/md/dm-log.c	2005-01-28 15:26:35.000000000 +0000
+++ source/drivers/md/dm-log.c	2005-01-28 15:31:18.000000000 +0000
@@ -129,7 +129,7 @@
 struct log_c {
 	struct dm_target *ti;
 	int touched;
-	sector_t region_size;
+	uint32_t region_size;
 	unsigned int region_count;
 	region_t sync_count;
 
@@ -292,7 +292,7 @@
 	enum sync sync = DEFAULTSYNC;
 
 	struct log_c *lc;
-	sector_t region_size;
+	uint32_t region_size;
 	unsigned int region_count;
 	size_t bitset_size;
 
@@ -313,12 +313,12 @@
 		}
 	}
 
-	if (sscanf(argv[0], SECTOR_FORMAT, &region_size) != 1) {
+	if (sscanf(argv[0], "%u", &region_size) != 1) {
 		DMWARN("invalid region size string");
 		return -EINVAL;
 	}
 
-	region_count = dm_div_up(ti->len, region_size);
+	region_count = dm_sector_div_up(ti->len, region_size);
 
 	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
 	if (!lc) {
@@ -508,7 +508,7 @@
 	return write_header(lc);
 }
 
-static sector_t core_get_region_size(struct dirty_log *log)
+static uint32_t core_get_region_size(struct dirty_log *log)
 {
 	struct log_c *lc = (struct log_c *) log->context;
 	return lc->region_size;
@@ -616,7 +616,7 @@
 		break;
 
 	case STATUSTYPE_TABLE:
-		DMEMIT("%s %u " SECTOR_FORMAT " ", log->type->name,
+		DMEMIT("%s %u %u ", log->type->name,
 		       lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
 		DMEMIT_SYNC;
 	}
@@ -637,7 +637,7 @@
 
 	case STATUSTYPE_TABLE:
 		format_dev_t(buffer, lc->log_dev->bdev->bd_dev);
-		DMEMIT("%s %u %s " SECTOR_FORMAT " ", log->type->name,
+		DMEMIT("%s %u %s %u ", log->type->name,
 		       lc->sync == DEFAULTSYNC ? 2 : 3, buffer,
 		       lc->region_size);
 		DMEMIT_SYNC;
--- diff/drivers/md/dm-log.h	2005-01-12 15:21:22.000000000 +0000
+++ source/drivers/md/dm-log.h	2005-01-28 15:30:32.000000000 +0000
@@ -39,7 +39,7 @@
 	 * Retrieves the smallest size of region that the log can
 	 * deal with.
 	 */
-	sector_t (*get_region_size)(struct dirty_log *log);
+	uint32_t (*get_region_size)(struct dirty_log *log);
 
         /*
 	 * A predicate to say whether a region is clean or not.
--- diff/drivers/md/dm-raid1.c	2005-01-28 15:26:59.000000000 +0000
+++ source/drivers/md/dm-raid1.c	2005-01-28 15:31:18.000000000 +0000
@@ -67,7 +67,7 @@
 struct mirror_set;
 struct region_hash {
 	struct mirror_set *ms;
-	sector_t region_size;
+	uint32_t region_size;
 	unsigned region_shift;
 
 	/* holds persistent region state */
@@ -135,7 +135,7 @@
 #define MIN_REGIONS 64
 #define MAX_RECOVERY 1
 static int rh_init(struct region_hash *rh, struct mirror_set *ms,
-		   struct dirty_log *log, sector_t region_size,
+		   struct dirty_log *log, uint32_t region_size,
 		   region_t nr_regions)
 {
 	unsigned int nr_buckets, max_buckets;
@@ -871,7 +871,7 @@
  * Target functions
  *---------------------------------------------------------------*/
 static struct mirror_set *alloc_context(unsigned int nr_mirrors,
-					sector_t region_size,
+					uint32_t region_size,
 					struct dm_target *ti,
 					struct dirty_log *dl)
 {
@@ -894,7 +894,7 @@
 
 	ms->ti = ti;
 	ms->nr_mirrors = nr_mirrors;
-	ms->nr_regions = dm_div_up(ti->len, region_size);
+	ms->nr_regions = dm_sector_div_up(ti->len, region_size);
 	ms->in_sync = 0;
 
 	if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) {
@@ -916,7 +916,7 @@
 	kfree(ms);
 }
 
-static inline int _check_region_size(struct dm_target *ti, sector_t size)
+static inline int _check_region_size(struct dm_target *ti, uint32_t size)
 {
 	return !(size % (PAGE_SIZE >> 9) || (size & (size - 1)) ||
 		 size > ti->len);
--- diff/drivers/md/dm-table.c	2005-01-28 15:26:59.000000000 +0000
+++ source/drivers/md/dm-table.c	2005-01-28 15:30:22.000000000 +0000
@@ -58,7 +58,7 @@
 /*
  * Similar to ceiling(log_size(n))
  */
-static unsigned int int_log(unsigned long n, unsigned long base)
+static unsigned int int_log(unsigned int n, unsigned int base)
 {
 	int result = 0;
 
--- diff/drivers/md/dm.c	2005-01-28 15:26:59.000000000 +0000
+++ source/drivers/md/dm.c	2005-01-28 15:31:32.000000000 +0000
@@ -331,8 +331,8 @@
 	 */
 	if (ti->split_io) {
 		sector_t boundary;
-		boundary = dm_round_up(offset + 1, ti->split_io) - offset;
-
+		boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
+			   - offset;
 		if (len > boundary)
 			len = boundary;
 	}
--- diff/drivers/md/dm.h	2005-01-28 15:26:59.000000000 +0000
+++ source/drivers/md/dm.h	2005-01-28 15:31:28.000000000 +0000
@@ -143,21 +143,22 @@
 }
 
 /*
- * ceiling(n / size) * size
+ * Ceiling(n / sz)
  */
-static inline unsigned long dm_round_up(unsigned long n, unsigned long size)
-{
-	unsigned long r = n % size;
-	return n + (r ? (size - r) : 0);
-}
+#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
+
+#define dm_sector_div_up(n, sz) ( \
+{ \
+	sector_t _r = ((n) + (sz) - 1); \
+	sector_div(_r, (sz)); \
+	_r; \
+} \
+)
 
 /*
- * Ceiling(n / size)
+ * ceiling(n / size) * size
  */
-static inline unsigned long dm_div_up(unsigned long n, unsigned long size)
-{
-	return dm_round_up(n, size) / size;
-}
+#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
 
 static inline sector_t to_sector(unsigned long n)
 {
--- diff/include/linux/device-mapper.h	2005-01-28 15:26:59.000000000 +0000
+++ source/include/linux/device-mapper.h	2005-01-28 15:46:17.000000000 +0000
@@ -108,6 +108,7 @@
 	sector_t len;
 
 	/* FIXME: turn this into a mask, and merge with io_restrictions */
+	/* Always a power of 2 */
 	sector_t split_io;
 
 	/*