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/* SPDX-License-Identifier: GPL-2.0 */
#define LINUX_IOMAP_H 1
#include <linux/atomic.h>
#include <linux/bitmap.h>
#include <linux/blk_types.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/mm_types.h>
#include <linux/blkdev.h>
struct address_space;
struct fiemap_extent_info;
struct inode;
struct iomap_writepage_ctx;
struct iov_iter;
struct kiocb;
struct page;
struct vm_area_struct;
struct vm_fault;
* Types of block ranges for iomap mappings:
#define IOMAP_HOLE 0 /* no blocks allocated, need allocation */
#define IOMAP_DELALLOC 1 /* delayed allocation blocks */
#define IOMAP_MAPPED 2 /* blocks allocated at @addr */
#define IOMAP_UNWRITTEN 3 /* blocks allocated at @addr in unwritten state */
#define IOMAP_INLINE 4 /* data inline in the inode */
* Flags reported by the file system from iomap_begin:
* IOMAP_F_NEW indicates that the blocks have been newly allocated and need
* zeroing for areas that no data is copied to.
* IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
* written data and requires fdatasync to commit them to persistent storage.
* This needs to take into account metadata changes that *may* be made at IO
* completion, such as file size updates from direct IO.
* IOMAP_F_SHARED indicates that the blocks are shared, and will need to be
* unshared as part a write.
* IOMAP_F_MERGED indicates that the iomap contains the merge of multiple block
* mappings.
* IOMAP_F_BUFFER_HEAD indicates that the file system requires the use of
* buffer heads for this mapping.
#define IOMAP_F_NEW 0x01
#define IOMAP_F_DIRTY 0x02
#define IOMAP_F_SHARED 0x04
#define IOMAP_F_MERGED 0x08
#define IOMAP_F_BUFFER_HEAD 0x10
* Flags set by the core iomap code during operations:
* IOMAP_F_SIZE_CHANGED indicates to the iomap_end method that the file size
* has changed as the result of this write operation.
#define IOMAP_F_SIZE_CHANGED 0x100
* 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;
static inline sector_t
iomap_sector(struct iomap *iomap, loff_t pos)
return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
* 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 */
#define IOMAP_DIRECT (1 << 4) /* direct I/O */
#define IOMAP_NOWAIT (1 << 5) /* do not block */
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,
struct iomap *srcmap);
* 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);
* Main iomap iterator function.
typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
void *data, struct iomap *iomap, struct iomap *srcmap);
loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
unsigned flags, const struct iomap_ops *ops, void *data,
iomap_actor_t actor);
ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops);
int iomap_readpage(struct page *page, const struct iomap_ops *ops);
void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
int iomap_set_page_dirty(struct page *page);
int iomap_is_partially_uptodate(struct page *page, unsigned long from,
unsigned long count);
int iomap_releasepage(struct page *page, gfp_t gfp_mask);
void iomap_invalidatepage(struct page *page, unsigned int offset,
unsigned int len);
int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
struct page *page, enum migrate_mode mode);
#define iomap_migrate_page NULL
int iomap_file_unshare(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);
vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
const struct iomap_ops *ops);
int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 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);
sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
const struct iomap_ops *ops);
* Structure for writeback I/O completions.
struct iomap_ioend {
struct list_head io_list; /* next ioend in chain */
u16 io_type;
u16 io_flags; /* IOMAP_F_* */
struct inode *io_inode; /* file being written to */
size_t io_size; /* size of the extent */
loff_t io_offset; /* offset in the file */
void *io_private; /* file system private data */
struct bio *io_bio; /* bio being built */
struct bio io_inline_bio; /* MUST BE LAST! */
struct iomap_writeback_ops {
* Required, maps the blocks so that writeback can be performed on
* the range starting at offset.
int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
loff_t offset);
* Optional, allows the file systems to perform actions just before
* submitting the bio and/or override the bio end_io handler for complex
* operations like copy on write extent manipulation or unwritten extent
* conversions.
int (*prepare_ioend)(struct iomap_ioend *ioend, int status);
* Optional, allows the file system to discard state on a page where
* we failed to submit any I/O.
void (*discard_page)(struct page *page);
struct iomap_writepage_ctx {
struct iomap iomap;
struct iomap_ioend *ioend;
const struct iomap_writeback_ops *ops;
void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
void iomap_ioend_try_merge(struct iomap_ioend *ioend,
struct list_head *more_ioends,
void (*merge_private)(struct iomap_ioend *ioend,
struct iomap_ioend *next));
void iomap_sort_ioends(struct list_head *ioend_list);
int iomap_writepage(struct page *page, struct writeback_control *wbc,
struct iomap_writepage_ctx *wpc,
const struct iomap_writeback_ops *ops);
int iomap_writepages(struct address_space *mapping,
struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
const struct iomap_writeback_ops *ops);
* Flags for direct I/O ->end_io:
#define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
#define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
struct iomap_dio_ops {
int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
unsigned flags);
blk_qc_t (*submit_io)(struct inode *inode, struct iomap *iomap,
struct bio *bio, loff_t file_offset);
ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
bool wait_for_completion);
int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
struct file;
struct swap_info_struct;
int iomap_swapfile_activate(struct swap_info_struct *sis,
struct file *swap_file, sector_t *pagespan,
const struct iomap_ops *ops);
# define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
#endif /* CONFIG_SWAP */
#endif /* LINUX_IOMAP_H */