btrfs: fix stat blocks accounting

Round inode bytes and delalloc bytes up to real blocksize before
converting to sector size. Otherwise eg. files smaller than 512
are reported with zero blocks due to incorrect rounding.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/inode.c

@@ -6794,11 +6794,13 @@ static int btrfs_getattr(struct vfsmount *mnt,
 			 struct dentry *dentry, struct kstat *stat)
 {
 	struct inode *inode = dentry->d_inode;
+	u32 blocksize = inode->i_sb->s_blocksize;
+
 	generic_fillattr(inode, stat);
 	stat->dev = BTRFS_I(inode)->root->anon_dev;
 	stat->blksize = PAGE_CACHE_SIZE;
-	stat->blocks = (inode_get_bytes(inode) +
-			BTRFS_I(inode)->delalloc_bytes) >> 9;
+	stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
+		ALIGN(BTRFS_I(inode)->delalloc_bytes, blocksize)) >> 9;
 	return 0;
 }