udf: convert to new aops

Convert udf to new aops. Also seem to have fixed pagecache corruption in
udf_adinicb_commit_write -- page was marked uptodate when it is not. Also,
fixed the silly setup where prepare_write was doing a kmap to be used in
commit_write: just do kmap_atomic in write_end. Use libfs helpers to make
this easier.

Signed-off-by: Nick Piggin <[e-mail]>
Cc: <[e-mail]>
Cc: Jan Kara <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/udf/file.c

···
 	return 0;
 }
 
-static int udf_adinicb_prepare_write(struct file *file, struct page *page,
-				     unsigned offset, unsigned to)
+static int udf_adinicb_write_end(struct file *file,
+			struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *page, void *fsdata)
 {
-	kmap(page);
-	return 0;
-}
+	struct inode *inode = mapping->host;
+	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
+	char *kaddr;
 
-static int udf_adinicb_commit_write(struct file *file, struct page *page,
-				    unsigned offset, unsigned to)
-{
-	struct inode *inode = page->mapping->host;
-	char *kaddr = page_address(page);
-
+	kaddr = kmap_atomic(page, KM_USER0);
 	memcpy(UDF_I_DATA(inode) + UDF_I_LENEATTR(inode) + offset,
-	       kaddr + offset, to - offset);
-	mark_inode_dirty(inode);
-	SetPageUptodate(page);
-	kunmap(page);
-	/* only one page here */
-	if (to > inode->i_size)
-		inode->i_size = to;
-	return 0;
+		kaddr + offset, copied);
+	kunmap_atomic(kaddr, KM_USER0);
+
+	return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
 }
 
 const struct address_space_operations udf_adinicb_aops = {
 	.readpage	= udf_adinicb_readpage,
 	.writepage	= udf_adinicb_writepage,
 	.sync_page	= block_sync_page,
-	.prepare_write	= udf_adinicb_prepare_write,
-	.commit_write	= udf_adinicb_commit_write,
+	.write_begin = simple_write_begin,
+	.write_end = udf_adinicb_write_end,
 };
 
 static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,

fs/udf/inode.c

···
 	return block_read_full_page(page, udf_get_block);
 }
 
-static int udf_prepare_write(struct file *file, struct page *page,
-			     unsigned from, unsigned to)
+static int udf_write_begin(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned flags,
+			struct page **pagep, void **fsdata)
 {
-	return block_prepare_write(page, from, to, udf_get_block);
+	*pagep = NULL;
+	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
+				udf_get_block);
 }
 
 static sector_t udf_bmap(struct address_space *mapping, sector_t block)
···
 	.readpage	= udf_readpage,
 	.writepage	= udf_writepage,
 	.sync_page	= block_sync_page,
-	.prepare_write	= udf_prepare_write,
-	.commit_write	= generic_commit_write,
+	.write_begin		= udf_write_begin,
+	.write_end		= generic_write_end,
 	.bmap		= udf_bmap,
 };