^^&&^^

Edit File: iomap.h

#ifndef LINUX_IOMAP_H
#define LINUX_IOMAP_H 1

#include <linux/types.h>
#ifndef __GENKSYMS__
#include <linux/aio.h>
#endif

struct fiemap_extent_info;
struct inode;
struct kiocb;
struct page;
struct vm_area_struct;
struct vm_fault;

/*
 * Types of block ranges for iomap mappings:
 */
#define IOMAP_HOLE	0x01	/* no blocks allocated, need allocation */
#define IOMAP_DELALLOC	0x02	/* delayed allocation blocks */
#define IOMAP_MAPPED	0x03	/* blocks allocated at @addr */
#define IOMAP_UNWRITTEN	0x04	/* blocks allocated at @addr in unwritten state */
#define IOMAP_INLINE	0x05	/* data inline in the inode */

/*
 * Flags for all iomap mappings:
 *
 * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
 * written data and requires fdatasync to commit them to persistent storage.
 */
#define IOMAP_F_NEW		0x01	/* blocks have been newly allocated */
#define IOMAP_F_DIRTY		0x02	/* uncommitted metadata */
#define IOMAP_F_SIZE_CHANGED	0x08	/* file size has changed */

/*
 * Flags that only need to be reported for IOMAP_REPORT requests:
 */
#define IOMAP_F_MERGED		0x10	/* contains multiple blocks/extents */
#define IOMAP_F_SHARED		0x20	/* block shared with another file */

/*
 * Flags from 0x1000 up are for file system specific usage:
 */
#define IOMAP_F_PRIVATE		0x1000

/*
 * Magic value for addr:
 */
#define IOMAP_NULL_ADDR -1ULL	/* addr is not valid */

struct iomap_page_ops;

struct iomap {
	u64			addr; /* disk offset of mapping, bytes */
	loff_t			offset;	/* file offset of mapping, bytes */
	u64			length;	/* length of mapping, bytes */
	u16			type;	/* type of mapping */
	u16			flags;	/* flags for mapping */
	struct block_device	*bdev;	/* block device for I/O */
	struct dax_device	*dax_dev; /* dax_dev for dax operations */
	void			*inline_data;
	void			*private; /* filesystem private */
	const struct iomap_page_ops *page_ops;
};

/*
 * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
 * and page_done will be called for each page written to.  This only applies to
 * buffered writes as unbuffered writes will not typically have pages
 * associated with them.
 *
 * When page_prepare succeeds, page_done will always be called to do any
 * cleanup work necessary.  In that page_done call, @page will be NULL if the
 * associated page could not be obtained.
 */
struct iomap_page_ops {
	int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,
			struct iomap *iomap);
	void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
			struct page *page, struct iomap *iomap);
};

/*
 * Flags for iomap_begin / iomap_end.  No flag implies a read.
 */
#define IOMAP_WRITE		(1 << 0) /* writing, must allocate blocks */
#define IOMAP_ZERO		(1 << 1) /* zeroing operation, may skip holes */
#define IOMAP_REPORT		(1 << 2) /* report extent status, e.g. FIEMAP */
#define IOMAP_FAULT		(1 << 3) /* mapping for page fault */

struct iomap_ops {
	/*
	 * Return the existing mapping at pos, or reserve space starting at
	 * pos for up to length, as long as we can do it as a single mapping.
	 * The actual length is returned in iomap->length.
	 */
	int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
			unsigned flags, struct iomap *iomap);

/*
	 * Commit and/or unreserve space previous allocated using iomap_begin.
	 * Written indicates the length of the successful write operation which
	 * needs to be commited, while the rest needs to be unreserved.
	 * Written might be zero if no data was written.
	 */
	int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
			ssize_t written, unsigned flags, struct iomap *iomap);
};

ssize_t
iomap_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
		unsigned long nr_segs, loff_t pos, loff_t *ppos,
		size_t ocount, const struct iomap_ops *ops);
int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
		const struct iomap_ops *ops);
int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
		bool *did_zero, const struct iomap_ops *ops);
int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
		const struct iomap_ops *ops);
int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
		const struct iomap_ops *ops);
int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
		loff_t start, loff_t len, const struct iomap_ops *ops);
loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
		const struct iomap_ops *ops);
loff_t iomap_seek_data(struct inode *inode, loff_t offset,
		const struct iomap_ops *ops);

#endif /* LINUX_IOMAP_H */