275 lines
9.1 KiB
C
275 lines
9.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef LINUX_IOMAP_H
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#define LINUX_IOMAP_H 1
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#include <linux/atomic.h>
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#include <linux/bitmap.h>
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#include <linux/blk_types.h>
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#include <linux/mm.h>
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#include <linux/types.h>
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#include <linux/mm_types.h>
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#include <linux/blkdev.h>
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struct address_space;
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struct fiemap_extent_info;
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struct inode;
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struct iomap_writepage_ctx;
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struct iov_iter;
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struct kiocb;
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struct page;
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struct vm_area_struct;
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struct vm_fault;
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/*
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* Types of block ranges for iomap mappings:
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*/
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#define IOMAP_HOLE 0 /* no blocks allocated, need allocation */
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#define IOMAP_DELALLOC 1 /* delayed allocation blocks */
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#define IOMAP_MAPPED 2 /* blocks allocated at @addr */
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#define IOMAP_UNWRITTEN 3 /* blocks allocated at @addr in unwritten state */
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#define IOMAP_INLINE 4 /* data inline in the inode */
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/*
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* Flags reported by the file system from iomap_begin:
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*
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* IOMAP_F_NEW indicates that the blocks have been newly allocated and need
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* zeroing for areas that no data is copied to.
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*
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* IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
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* written data and requires fdatasync to commit them to persistent storage.
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* This needs to take into account metadata changes that *may* be made at IO
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* completion, such as file size updates from direct IO.
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*
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* IOMAP_F_SHARED indicates that the blocks are shared, and will need to be
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* unshared as part a write.
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*
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* IOMAP_F_MERGED indicates that the iomap contains the merge of multiple block
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* mappings.
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*
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* IOMAP_F_BUFFER_HEAD indicates that the file system requires the use of
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* buffer heads for this mapping.
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*/
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#define IOMAP_F_NEW 0x01
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#define IOMAP_F_DIRTY 0x02
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#define IOMAP_F_SHARED 0x04
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#define IOMAP_F_MERGED 0x08
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#define IOMAP_F_BUFFER_HEAD 0x10
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/*
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* Flags set by the core iomap code during operations:
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*
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* IOMAP_F_SIZE_CHANGED indicates to the iomap_end method that the file size
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* has changed as the result of this write operation.
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*/
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#define IOMAP_F_SIZE_CHANGED 0x100
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/*
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* Flags from 0x1000 up are for file system specific usage:
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*/
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#define IOMAP_F_PRIVATE 0x1000
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/*
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* Magic value for addr:
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*/
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#define IOMAP_NULL_ADDR -1ULL /* addr is not valid */
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struct iomap_page_ops;
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struct iomap {
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u64 addr; /* disk offset of mapping, bytes */
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loff_t offset; /* file offset of mapping, bytes */
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u64 length; /* length of mapping, bytes */
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u16 type; /* type of mapping */
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u16 flags; /* flags for mapping */
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struct block_device *bdev; /* block device for I/O */
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struct dax_device *dax_dev; /* dax_dev for dax operations */
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void *inline_data;
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void *private; /* filesystem private */
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const struct iomap_page_ops *page_ops;
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};
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static inline sector_t
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iomap_sector(struct iomap *iomap, loff_t pos)
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{
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return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
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}
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/*
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* When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
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* and page_done will be called for each page written to. This only applies to
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* buffered writes as unbuffered writes will not typically have pages
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* associated with them.
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*
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* When page_prepare succeeds, page_done will always be called to do any
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* cleanup work necessary. In that page_done call, @page will be NULL if the
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* associated page could not be obtained.
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*/
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struct iomap_page_ops {
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int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,
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struct iomap *iomap);
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void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
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struct page *page, struct iomap *iomap);
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};
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/*
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* Flags for iomap_begin / iomap_end. No flag implies a read.
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*/
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#define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */
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#define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */
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#define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */
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#define IOMAP_FAULT (1 << 3) /* mapping for page fault */
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#define IOMAP_DIRECT (1 << 4) /* direct I/O */
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#define IOMAP_NOWAIT (1 << 5) /* do not block */
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struct iomap_ops {
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/*
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* Return the existing mapping at pos, or reserve space starting at
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* pos for up to length, as long as we can do it as a single mapping.
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* The actual length is returned in iomap->length.
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*/
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int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
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unsigned flags, struct iomap *iomap,
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struct iomap *srcmap);
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/*
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* Commit and/or unreserve space previous allocated using iomap_begin.
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* Written indicates the length of the successful write operation which
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* needs to be commited, while the rest needs to be unreserved.
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* Written might be zero if no data was written.
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*/
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int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
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ssize_t written, unsigned flags, struct iomap *iomap);
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};
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/*
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* Main iomap iterator function.
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*/
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typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
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void *data, struct iomap *iomap, struct iomap *srcmap);
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loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
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unsigned flags, const struct iomap_ops *ops, void *data,
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iomap_actor_t actor);
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ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
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const struct iomap_ops *ops);
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int iomap_readpage(struct page *page, const struct iomap_ops *ops);
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void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
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int iomap_set_page_dirty(struct page *page);
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int iomap_is_partially_uptodate(struct page *page, unsigned long from,
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unsigned long count);
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int iomap_releasepage(struct page *page, gfp_t gfp_mask);
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void iomap_invalidatepage(struct page *page, unsigned int offset,
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unsigned int len);
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#ifdef CONFIG_MIGRATION
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int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
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struct page *page, enum migrate_mode mode);
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#else
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#define iomap_migrate_page NULL
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#endif
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int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
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const struct iomap_ops *ops);
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int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
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bool *did_zero, const struct iomap_ops *ops);
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int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
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const struct iomap_ops *ops);
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vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
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const struct iomap_ops *ops);
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int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
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u64 start, u64 len, const struct iomap_ops *ops);
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loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
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const struct iomap_ops *ops);
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loff_t iomap_seek_data(struct inode *inode, loff_t offset,
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const struct iomap_ops *ops);
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sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
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const struct iomap_ops *ops);
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/*
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* Structure for writeback I/O completions.
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*/
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struct iomap_ioend {
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struct list_head io_list; /* next ioend in chain */
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u16 io_type;
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u16 io_flags; /* IOMAP_F_* */
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struct inode *io_inode; /* file being written to */
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size_t io_size; /* size of the extent */
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loff_t io_offset; /* offset in the file */
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void *io_private; /* file system private data */
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struct bio *io_bio; /* bio being built */
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struct bio io_inline_bio; /* MUST BE LAST! */
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};
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struct iomap_writeback_ops {
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/*
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* Required, maps the blocks so that writeback can be performed on
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* the range starting at offset.
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*/
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int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
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loff_t offset);
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/*
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* Optional, allows the file systems to perform actions just before
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* submitting the bio and/or override the bio end_io handler for complex
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* operations like copy on write extent manipulation or unwritten extent
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* conversions.
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*/
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int (*prepare_ioend)(struct iomap_ioend *ioend, int status);
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/*
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* Optional, allows the file system to discard state on a page where
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* we failed to submit any I/O.
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*/
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void (*discard_page)(struct page *page);
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};
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struct iomap_writepage_ctx {
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struct iomap iomap;
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struct iomap_ioend *ioend;
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const struct iomap_writeback_ops *ops;
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};
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void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
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void iomap_ioend_try_merge(struct iomap_ioend *ioend,
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struct list_head *more_ioends,
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void (*merge_private)(struct iomap_ioend *ioend,
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struct iomap_ioend *next));
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void iomap_sort_ioends(struct list_head *ioend_list);
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int iomap_writepage(struct page *page, struct writeback_control *wbc,
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struct iomap_writepage_ctx *wpc,
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const struct iomap_writeback_ops *ops);
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int iomap_writepages(struct address_space *mapping,
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struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
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const struct iomap_writeback_ops *ops);
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/*
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* Flags for direct I/O ->end_io:
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*/
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#define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
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#define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
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struct iomap_dio_ops {
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int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
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unsigned flags);
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blk_qc_t (*submit_io)(struct inode *inode, struct iomap *iomap,
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struct bio *bio, loff_t file_offset);
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};
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ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
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const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
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bool wait_for_completion);
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int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
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#ifdef CONFIG_SWAP
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struct file;
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struct swap_info_struct;
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int iomap_swapfile_activate(struct swap_info_struct *sis,
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struct file *swap_file, sector_t *pagespan,
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const struct iomap_ops *ops);
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#else
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# define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
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#endif /* CONFIG_SWAP */
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#endif /* LINUX_IOMAP_H */
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