Btrfs: use linux/sizes.h to represent constants

We use many constants to represent size and offset value.  And to make
code readable we use '256 * 1024 * 1024' instead of '268435456' to
represent '256MB'.  However we can make far more readable with 'SZ_256MB'
which is defined in the 'linux/sizes.h'.

So this patch replaces 'xxx * 1024 * 1024' kind of expression with
single 'SZ_xxxMB' if 'xxx' is a power of 2 then 'xxx * SZ_1M' if 'xxx' is
not a power of 2. And I haven't touched to '4096' & '8192' because it's
more intuitive than 'SZ_4KB' & 'SZ_8KB'.

Signed-off-by: Byongho Lee <bhlee.kernel@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ioctl.c

@@ -1016,7 +1016,7 @@ static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em)
 	if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE)
 		ret = false;
 	else if ((em->block_start + em->block_len == next->block_start) &&
-		 (em->block_len > 128 * 1024 && next->block_len > 128 * 1024))
+		 (em->block_len > SZ_128K && next->block_len > SZ_128K))
 		ret = false;
 
 	free_extent_map(next);
@@ -1262,9 +1262,9 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
 	int defrag_count = 0;
 	int compress_type = BTRFS_COMPRESS_ZLIB;
 	u32 extent_thresh = range->extent_thresh;
-	unsigned long max_cluster = (256 * 1024) >> PAGE_CACHE_SHIFT;
+	unsigned long max_cluster = SZ_256K >> PAGE_CACHE_SHIFT;
 	unsigned long cluster = max_cluster;
-	u64 new_align = ~((u64)128 * 1024 - 1);
+	u64 new_align = ~((u64)SZ_128K - 1);
 	struct page **pages = NULL;
 
 	if (isize == 0)
@@ -1281,7 +1281,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
 	}
 
 	if (extent_thresh == 0)
-		extent_thresh = 256 * 1024;
+		extent_thresh = SZ_256K;
 
 	/*
 	 * if we were not given a file, allocate a readahead
@@ -1313,7 +1313,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
 
 	if (newer_than) {
 		ret = find_new_extents(root, inode, newer_than,
-				       &newer_off, 64 * 1024);
+				       &newer_off, SZ_64K);
 		if (!ret) {
 			range->start = newer_off;
 			/*
@@ -1403,9 +1403,8 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
 			newer_off = max(newer_off + 1,
 					(u64)i << PAGE_CACHE_SHIFT);
 
-			ret = find_new_extents(root, inode,
-					       newer_than, &newer_off,
-					       64 * 1024);
+			ret = find_new_extents(root, inode, newer_than,
+					       &newer_off, SZ_64K);
 			if (!ret) {
 				range->start = newer_off;
 				i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
@@ -1571,7 +1570,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 		new_size = old_size + new_size;
 	}
 
-	if (new_size < 256 * 1024 * 1024) {
+	if (new_size < SZ_256M) {
 		ret = -EINVAL;
 		goto out_free;
 	}
@@ -2160,7 +2159,7 @@ static noinline int btrfs_ioctl_tree_search_v2(struct file *file,
 	struct inode *inode;
 	int ret;
 	size_t buf_size;
-	const size_t buf_limit = 16 * 1024 * 1024;
+	const size_t buf_limit = SZ_16M;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
@@ -3096,7 +3095,7 @@ out_unlock:
 	return ret;
 }
 
-#define BTRFS_MAX_DEDUPE_LEN	(16 * 1024 * 1024)
+#define BTRFS_MAX_DEDUPE_LEN	SZ_16M
 
 static long btrfs_ioctl_file_extent_same(struct file *file,
 			struct btrfs_ioctl_same_args __user *argp)
@@ -4524,7 +4523,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
 		goto out;
 	}
 
-	size = min_t(u32, loi->size, 64 * 1024);
+	size = min_t(u32, loi->size, SZ_64K);
 	inodes = init_data_container(size);
 	if (IS_ERR(inodes)) {
 		ret = PTR_ERR(inodes);