1 files changed, 93 insertions, 0 deletions
diff --git a/fs/ntfs/aops.h b/fs/ntfs/aops.h
new file mode 100644
index 000000000..f0962d46b
--- /dev/null
+++ b/fs/ntfs/aops.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/**
+ * aops.h - Defines for NTFS kernel address space operations and page cache
+ *	    handling.  Part of the Linux-NTFS project.
+ *
+ * Copyright (c) 2001-2004 Anton Altaparmakov
+ * Copyright (c) 2002 Richard Russon
+ */
+
+#ifndef _LINUX_NTFS_AOPS_H
+#define _LINUX_NTFS_AOPS_H
+
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+#include <linux/fs.h>
+
+#include "inode.h"
+
+/**
+ * ntfs_unmap_page - release a page that was mapped using ntfs_map_page()
+ * @page:	the page to release
+ *
+ * Unpin, unmap and release a page that was obtained from ntfs_map_page().
+ */
+static inline void ntfs_unmap_page(struct page *page)
+{
+	kunmap(page);
+	put_page(page);
+}
+
+/**
+ * ntfs_map_page - map a page into accessible memory, reading it if necessary
+ * @mapping:	address space for which to obtain the page
+ * @index:	index into the page cache for @mapping of the page to map
+ *
+ * Read a page from the page cache of the address space @mapping at position
+ * @index, where @index is in units of PAGE_SIZE, and not in bytes.
+ *
+ * If the page is not in memory it is loaded from disk first using the readpage
+ * method defined in the address space operations of @mapping and the page is
+ * added to the page cache of @mapping in the process.
+ *
+ * If the page belongs to an mst protected attribute and it is marked as such
+ * in its ntfs inode (NInoMstProtected()) the mst fixups are applied but no
+ * error checking is performed.  This means the caller has to verify whether
+ * the ntfs record(s) contained in the page are valid or not using one of the
+ * ntfs_is_XXXX_record{,p}() macros, where XXXX is the record type you are
+ * expecting to see.  (For details of the macros, see fs/ntfs/layout.h.)
+ *
+ * If the page is in high memory it is mapped into memory directly addressible
+ * by the kernel.
+ *
+ * Finally the page count is incremented, thus pinning the page into place.
+ *
+ * The above means that page_address(page) can be used on all pages obtained
+ * with ntfs_map_page() to get the kernel virtual address of the page.
+ *
+ * When finished with the page, the caller has to call ntfs_unmap_page() to
+ * unpin, unmap and release the page.
+ *
+ * Note this does not grant exclusive access. If such is desired, the caller
+ * must provide it independently of the ntfs_{un}map_page() calls by using
+ * a {rw_}semaphore or other means of serialization. A spin lock cannot be
+ * used as ntfs_map_page() can block.
+ *
+ * The unlocked and uptodate page is returned on success or an encoded error
+ * on failure. Caller has to test for error using the IS_ERR() macro on the
+ * return value. If that evaluates to 'true', the negative error code can be
+ * obtained using PTR_ERR() on the return value of ntfs_map_page().
+ */
+static inline struct page *ntfs_map_page(struct address_space *mapping,
+		unsigned long index)
+{
+	struct page *page = read_mapping_page(mapping, index, NULL);
+
+	if (!IS_ERR(page)) {
+		kmap(page);
+		if (!PageError(page))
+			return page;
+		ntfs_unmap_page(page);
+		return ERR_PTR(-EIO);
+	}
+	return page;
+}
+
+#ifdef NTFS_RW
+
+extern void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs);
+
+#endif /* NTFS_RW */
+
+#endif /* _LINUX_NTFS_AOPS_H */