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

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>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/md/dm-crypt.c

@@ -329,7 +329,7 @@ crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
                    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;

drivers/md/dm-log.c

@@ -129,7 +129,7 @@ struct log_header {
 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 @@ static int core_ctr(struct dirty_log *log, struct dm_target *ti,
 	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 @@ static int core_ctr(struct dirty_log *log, struct dm_target *ti,
 		}
 	}
 
-	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 @@ static int disk_resume(struct dirty_log *log)
 	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 @@ static int core_status(struct dirty_log *log, status_type_t status,
 		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 @@ static int disk_status(struct dirty_log *log, status_type_t status,
 
 	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;

drivers/md/dm-log.h

@@ -39,7 +39,7 @@ struct dirty_log_type {
 	 * 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.

drivers/md/dm-raid1.c

@@ -67,7 +67,7 @@ static inline void wake(void)
 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 @@ static void region_free(void *element, void *pool_data)
 #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 @@ static void do_work(void *ignored)
  * 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 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors,
 
 	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 @@ static void free_context(struct mirror_set *ms, struct dm_target *ti,
 	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);

drivers/md/dm-table.c

@@ -58,7 +58,7 @@ struct dm_table {
 /*
  * 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;
 

drivers/md/dm.c

@@ -331,8 +331,8 @@ static sector_t max_io_len(struct mapped_device *md,
 	 */
 	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;
 	}

drivers/md/dm.h

@@ -143,21 +143,22 @@ static inline int array_too_big(unsigned long fixed, unsigned long obj,
 }
 
 /*
- * 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)
 {

include/linux/device-mapper.h

@@ -108,6 +108,7 @@ struct dm_target {
 	sector_t len;
 
 	/* FIXME: turn this into a mask, and merge with io_restrictions */
+	/* Always a power of 2 */
 	sector_t split_io;
 
 	/*