dm snapshot: use unsigned integer chunk size

Use unsigned integer chunk size.

Maximum chunk size is 512kB, there won't ever be need to use 4GB chunk size,
so the number can be 32-bit. This fixes compiler failure on 32-bit systems
with large block devices.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-exception-store.c

@@ -155,7 +155,8 @@ static int set_chunk_size(struct dm_exception_store *store,
 	char *value;
 
 	chunk_size_ulong = simple_strtoul(chunk_size_arg, &value, 10);
-	if (*chunk_size_arg == '\0' || *value != '\0') {
+	if (*chunk_size_arg == '\0' || *value != '\0' ||
+	    chunk_size_ulong > UINT_MAX) {
 		*error = "Invalid chunk size";
 		return -EINVAL;
 	}
@@ -171,34 +172,35 @@ static int set_chunk_size(struct dm_exception_store *store,
 	 */
 	chunk_size_ulong = round_up(chunk_size_ulong, PAGE_SIZE >> 9);
 
-	return dm_exception_store_set_chunk_size(store, chunk_size_ulong,
+	return dm_exception_store_set_chunk_size(store,
+						 (unsigned) chunk_size_ulong,
 						 error);
 }
 
 int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
-				      unsigned long chunk_size_ulong,
+				      unsigned chunk_size,
 				      char **error)
 {
 	/* Check chunk_size is a power of 2 */
-	if (!is_power_of_2(chunk_size_ulong)) {
+	if (!is_power_of_2(chunk_size)) {
 		*error = "Chunk size is not a power of 2";
 		return -EINVAL;
 	}
 
 	/* Validate the chunk size against the device block size */
-	if (chunk_size_ulong % (bdev_logical_block_size(store->cow->bdev) >> 9)) {
+	if (chunk_size % (bdev_logical_block_size(store->cow->bdev) >> 9)) {
 		*error = "Chunk size is not a multiple of device blocksize";
 		return -EINVAL;
 	}
 
-	if (chunk_size_ulong > INT_MAX >> SECTOR_SHIFT) {
+	if (chunk_size > INT_MAX >> SECTOR_SHIFT) {
 		*error = "Chunk size is too high";
 		return -EINVAL;
 	}
 
-	store->chunk_size = chunk_size_ulong;
-	store->chunk_mask = chunk_size_ulong - 1;
-	store->chunk_shift = ffs(chunk_size_ulong) - 1;
+	store->chunk_size = chunk_size;
+	store->chunk_mask = chunk_size - 1;
+	store->chunk_shift = ffs(chunk_size) - 1;
 
 	return 0;
 }

drivers/md/dm-exception-store.h

@@ -101,9 +101,9 @@ struct dm_exception_store {
 	struct dm_dev *cow;
 
 	/* Size of data blocks saved - must be a power of 2 */
-	chunk_t chunk_size;
-	chunk_t chunk_mask;
-	chunk_t chunk_shift;
+	unsigned chunk_size;
+	unsigned chunk_mask;
+	unsigned chunk_shift;
 
 	void *context;
 };
@@ -169,7 +169,7 @@ int dm_exception_store_type_register(struct dm_exception_store_type *type);
 int dm_exception_store_type_unregister(struct dm_exception_store_type *type);
 
 int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
-				      unsigned long chunk_size_ulong,
+				      unsigned chunk_size,
 				      char **error);
 
 int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,

drivers/md/dm-snap-persistent.c

@@ -284,12 +284,13 @@ static int read_header(struct pstore *ps, int *new_snapshot)
 {
 	int r;
 	struct disk_header *dh;
-	chunk_t chunk_size;
+	unsigned chunk_size;
 	int chunk_size_supplied = 1;
 	char *chunk_err;
 
 	/*
-	 * Use default chunk size (or hardsect_size, if larger) if none supplied
+	 * Use default chunk size (or logical_block_size, if larger)
+	 * if none supplied
 	 */
 	if (!ps->store->chunk_size) {
 		ps->store->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS,
@@ -334,19 +335,18 @@ static int read_header(struct pstore *ps, int *new_snapshot)
 		return 0;
 
 	if (chunk_size_supplied)
-		DMWARN("chunk size %llu in device metadata overrides "
-		       "table chunk size of %llu.",
-		       (unsigned long long)chunk_size,
-		       (unsigned long long)ps->store->chunk_size);
+		DMWARN("chunk size %u in device metadata overrides "
+		       "table chunk size of %u.",
+		       chunk_size, ps->store->chunk_size);
 
 	/* We had a bogus chunk_size. Fix stuff up. */
 	free_area(ps);
 
 	r = dm_exception_store_set_chunk_size(ps->store, chunk_size,
 					      &chunk_err);
 	if (r) {
-		DMERR("invalid on-disk chunk size %llu: %s.",
-		      (unsigned long long)chunk_size, chunk_err);
+		DMERR("invalid on-disk chunk size %u: %s.",
+		      chunk_size, chunk_err);
 		return r;
 	}
 

drivers/md/dm-snap.c

@@ -961,7 +961,7 @@ static void start_copy(struct dm_snap_pending_exception *pe)
 
 	src.bdev = bdev;
 	src.sector = chunk_to_sector(s->store, pe->e.old_chunk);
-	src.count = min(s->store->chunk_size, dev_size - src.sector);
+	src.count = min((sector_t)s->store->chunk_size, dev_size - src.sector);
 
 	dest.bdev = s->store->cow->bdev;
 	dest.sector = chunk_to_sector(s->store, pe->e.new_chunk);
@@ -1402,7 +1402,7 @@ static void origin_resume(struct dm_target *ti)
 	struct dm_dev *dev = ti->private;
 	struct dm_snapshot *snap;
 	struct origin *o;
-	chunk_t chunk_size = 0;
+	unsigned chunk_size = 0;
 
 	down_read(&_origins_lock);
 	o = __lookup_origin(dev->bdev);