401 lines
14 KiB
C
401 lines
14 KiB
C
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/* 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_iter;
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struct iomap_dio;
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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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* IOMAP_F_XATTR indicates that the iomap is for an extended attribute extent
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* rather than a file data extent.
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*/
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#define IOMAP_F_NEW (1U << 0)
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#define IOMAP_F_DIRTY (1U << 1)
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#define IOMAP_F_SHARED (1U << 2)
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#define IOMAP_F_MERGED (1U << 3)
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#define IOMAP_F_BUFFER_HEAD (1U << 4)
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#define IOMAP_F_XATTR (1U << 5)
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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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* IOMAP_F_STALE indicates that the iomap is not valid any longer and the file
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* range it covers needs to be remapped by the high level before the operation
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* can proceed.
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*/
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#define IOMAP_F_SIZE_CHANGED (1U << 8)
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#define IOMAP_F_STALE (1U << 9)
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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 (1U << 12)
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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_folio_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_folio_ops *folio_ops;
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u64 validity_cookie; /* used with .iomap_valid() */
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};
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static inline sector_t iomap_sector(const 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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* Returns the inline data pointer for logical offset @pos.
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*/
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static inline void *iomap_inline_data(const struct iomap *iomap, loff_t pos)
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{
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return iomap->inline_data + pos - iomap->offset;
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}
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/*
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* Check if the mapping's length is within the valid range for inline data.
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* This is used to guard against accessing data beyond the page inline_data
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* points at.
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*/
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static inline bool iomap_inline_data_valid(const struct iomap *iomap)
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{
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return iomap->length <= PAGE_SIZE - offset_in_page(iomap->inline_data);
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}
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/*
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* When a filesystem sets folio_ops in an iomap mapping it returns, get_folio
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* and put_folio will be called for each folio written to. This only applies
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* to buffered writes as unbuffered writes will not typically have folios
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* associated with them.
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*
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* When get_folio succeeds, put_folio will always be called to do any
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* cleanup work necessary. put_folio is responsible for unlocking and putting
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* @folio.
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*/
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struct iomap_folio_ops {
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struct folio *(*get_folio)(struct iomap_iter *iter, loff_t pos,
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unsigned len);
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void (*put_folio)(struct inode *inode, loff_t pos, unsigned copied,
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struct folio *folio);
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/*
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* Check that the cached iomap still maps correctly to the filesystem's
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* internal extent map. FS internal extent maps can change while iomap
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* is iterating a cached iomap, so this hook allows iomap to detect that
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* the iomap needs to be refreshed during a long running write
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* operation.
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*
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* The filesystem can store internal state (e.g. a sequence number) in
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* iomap->validity_cookie when the iomap is first mapped to be able to
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* detect changes between mapping time and whenever .iomap_valid() is
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* called.
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*
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* This is called with the folio over the specified file position held
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* locked by the iomap code.
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*/
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bool (*iomap_valid)(struct inode *inode, const 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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#define IOMAP_OVERWRITE_ONLY (1 << 6) /* only pure overwrites allowed */
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#define IOMAP_UNSHARE (1 << 7) /* unshare_file_range */
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#ifdef CONFIG_FS_DAX
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#define IOMAP_DAX (1 << 8) /* DAX mapping */
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#else
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#define IOMAP_DAX 0
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#endif /* CONFIG_FS_DAX */
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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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* struct iomap_iter - Iterate through a range of a file
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* @inode: Set at the start of the iteration and should not change.
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* @pos: The current file position we are operating on. It is updated by
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* calls to iomap_iter(). Treat as read-only in the body.
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* @len: The remaining length of the file segment we're operating on.
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* It is updated at the same time as @pos.
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* @processed: The number of bytes processed by the body in the most recent
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* iteration, or a negative errno. 0 causes the iteration to stop.
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* @flags: Zero or more of the iomap_begin flags above.
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* @iomap: Map describing the I/O iteration
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* @srcmap: Source map for COW operations
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*/
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struct iomap_iter {
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struct inode *inode;
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loff_t pos;
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u64 len;
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s64 processed;
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unsigned flags;
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struct iomap iomap;
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struct iomap srcmap;
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void *private;
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};
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int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops);
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/**
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* iomap_length - length of the current iomap iteration
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* @iter: iteration structure
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*
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* Returns the length that the operation applies to for the current iteration.
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*/
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static inline u64 iomap_length(const struct iomap_iter *iter)
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{
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u64 end = iter->iomap.offset + iter->iomap.length;
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if (iter->srcmap.type != IOMAP_HOLE)
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end = min(end, iter->srcmap.offset + iter->srcmap.length);
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return min(iter->len, end - iter->pos);
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}
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/**
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* iomap_iter_srcmap - return the source map for the current iomap iteration
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* @i: iteration structure
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*
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* Write operations on file systems with reflink support might require a
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* source and a destination map. This function retourns the source map
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* for a given operation, which may or may no be identical to the destination
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* map in &i->iomap.
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*/
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static inline const struct iomap *iomap_iter_srcmap(const struct iomap_iter *i)
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{
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if (i->srcmap.type != IOMAP_HOLE)
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return &i->srcmap;
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return &i->iomap;
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}
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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_file_buffered_write_punch_delalloc(struct inode *inode,
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struct iomap *iomap, loff_t pos, loff_t length, ssize_t written,
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int (*punch)(struct inode *inode, loff_t pos, loff_t length));
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int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
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void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
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bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
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struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos);
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bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
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void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len);
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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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u32 io_folios; /* folios added to ioend */
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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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sector_t io_sector; /* start sector of ioend */
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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_folio)(struct folio *folio, loff_t pos);
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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 iomap_sort_ioends(struct list_head *ioend_list);
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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) */
|
||
|
|
#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);
|
||
|
|
void (*submit_io)(const struct iomap_iter *iter, struct bio *bio,
|
||
|
|
loff_t file_offset);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Filesystems wishing to attach private information to a direct io bio
|
||
|
|
* must provide a ->submit_io method that attaches the additional
|
||
|
|
* information to the bio and changes the ->bi_end_io callback to a
|
||
|
|
* custom function. This function should, at a minimum, perform any
|
||
|
|
* relevant post-processing of the bio and end with a call to
|
||
|
|
* iomap_dio_bio_end_io.
|
||
|
|
*/
|
||
|
|
struct bio_set *bio_set;
|
||
|
|
};
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Wait for the I/O to complete in iomap_dio_rw even if the kiocb is not
|
||
|
|
* synchronous.
|
||
|
|
*/
|
||
|
|
#define IOMAP_DIO_FORCE_WAIT (1 << 0)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Do not allocate blocks or zero partial blocks, but instead fall back to
|
||
|
|
* the caller by returning -EAGAIN. Used to optimize direct I/O writes that
|
||
|
|
* are not aligned to the file system block size.
|
||
|
|
*/
|
||
|
|
#define IOMAP_DIO_OVERWRITE_ONLY (1 << 1)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* When a page fault occurs, return a partial synchronous result and allow
|
||
|
|
* the caller to retry the rest of the operation after dealing with the page
|
||
|
|
* fault.
|
||
|
|
*/
|
||
|
|
#define IOMAP_DIO_PARTIAL (1 << 2)
|
||
|
|
|
||
|
|
ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
|
||
|
|
const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
|
||
|
|
unsigned int dio_flags, void *private, size_t done_before);
|
||
|
|
struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
|
||
|
|
const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
|
||
|
|
unsigned int dio_flags, void *private, size_t done_before);
|
||
|
|
ssize_t iomap_dio_complete(struct iomap_dio *dio);
|
||
|
|
void iomap_dio_bio_end_io(struct bio *bio);
|
||
|
|
|
||
|
|
#ifdef CONFIG_SWAP
|
||
|
|
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);
|
||
|
|
#else
|
||
|
|
# define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
|
||
|
|
#endif /* CONFIG_SWAP */
|
||
|
|
|
||
|
|
#endif /* LINUX_IOMAP_H */
|