fuse: Prepare to handle multiple pages in writeback
fuse: Prepare to handle multiple pages in writeback

The .writepages callback will issue writeback requests with more than one
page aboard. Make existing end/check code be aware of this.

Signed-off-by: Maxim Patlasov <a03f90017ab580fcc9558a98cd061c91599c42fd@parallels.com>
Signed-off-by: Miklos Szeredi <84cd5483a2f9acd1c37251cba7c2908448f221b8@suse.cz>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs