Please follow the given procedure to fill a pattern perfectly in the canvas:
Suppose your design size is 96 inches / 120 inches.
- Select the pattern to be repeated and copy it.
- Expand the canvas size by percentage (between 110% to 150%)
Image >> Canvas Size
- Paste the pattern and Repeat in the expanded canvas.
Replicate >> Entire >> Normal
- Select the whole repeated part and crop it.
Image >> Crop to selection (Shift + Ctrl + X )
- Go to Image >> Canvas Size again.
- Now give the original size of a carpet and crop it, setting the Anchor position at Middle.