fs/affs: bugfix: enable writes on OFS disks

We called unconditionally affs_bread_ino() with create 0 resulting in
"error (device ...): get_block(): strange block request 0"
when trying to write on AFFS OFS format.

This patch adds create parameter to that function.
0 for affs_readpage_ofs()
1 for affs_write_begin_ofs()

Bug was found here:
https://bugzilla.kernel.org/show_bug.cgi?id=114961

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/affs/file.c

@@ -499,7 +499,7 @@ affs_getemptyblk_ino(struct inode *inode, int block)
 }
 
 static int
-affs_do_readpage_ofs(struct page *page, unsigned to)
+affs_do_readpage_ofs(struct page *page, unsigned to, int create)
 {
 	struct inode *inode = page->mapping->host;
 	struct super_block *sb = inode->i_sb;
@@ -518,7 +518,7 @@ affs_do_readpage_ofs(struct page *page, unsigned to)
 	boff = tmp % bsize;
 
 	while (pos < to) {
-		bh = affs_bread_ino(inode, bidx, 0);
+		bh = affs_bread_ino(inode, bidx, create);
 		if (IS_ERR(bh))
 			return PTR_ERR(bh);
 		tmp = min(bsize - boff, to - pos);
@@ -620,7 +620,7 @@ affs_readpage_ofs(struct file *file, struct page *page)
 		memset(page_address(page) + to, 0, PAGE_SIZE - to);
 	}
 
-	err = affs_do_readpage_ofs(page, to);
+	err = affs_do_readpage_ofs(page, to, 0);
 	if (!err)
 		SetPageUptodate(page);
 	unlock_page(page);
@@ -657,7 +657,7 @@ static int affs_write_begin_ofs(struct file *file, struct address_space *mapping
 		return 0;
 
 	/* XXX: inefficient but safe in the face of short writes */
-	err = affs_do_readpage_ofs(page, PAGE_SIZE);
+	err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
 	if (err) {
 		unlock_page(page);
 		put_page(page);