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373 lines
12 KiB
373 lines
12 KiB
/* 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_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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#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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#define IOMAP_F_ZONE_APPEND 0x20 |
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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 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 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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void (*page_done)(struct inode *inode, loff_t pos, unsigned copied, |
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struct page *page); |
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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_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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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) */ |
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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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void (*submit_io)(const struct iomap_iter *iter, struct bio *bio, |
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loff_t file_offset); |
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/* |
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* Filesystems wishing to attach private information to a direct io bio |
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* must provide a ->submit_io method that attaches the additional |
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* information to the bio and changes the ->bi_end_io callback to a |
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* custom function. This function should, at a minimum, perform any |
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* relevant post-processing of the bio and end with a call to |
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* iomap_dio_bio_end_io. |
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*/ |
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struct bio_set *bio_set; |
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}; |
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/* |
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* Wait for the I/O to complete in iomap_dio_rw even if the kiocb is not |
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* synchronous. |
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*/ |
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#define IOMAP_DIO_FORCE_WAIT (1 << 0) |
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/* |
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* Do not allocate blocks or zero partial blocks, but instead fall back to |
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* the caller by returning -EAGAIN. Used to optimize direct I/O writes that |
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* are not aligned to the file system block size. |
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*/ |
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#define IOMAP_DIO_OVERWRITE_ONLY (1 << 1) |
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/* |
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* When a page fault occurs, return a partial synchronous result and allow |
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* the caller to retry the rest of the operation after dealing with the page |
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* fault. |
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*/ |
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#define IOMAP_DIO_PARTIAL (1 << 2) |
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/* |
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* The caller will sync the write if needed; do not sync it within |
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* iomap_dio_rw. Overrides IOMAP_DIO_FORCE_WAIT. |
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*/ |
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#define IOMAP_DIO_NOSYNC (1 << 3) |
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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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unsigned int dio_flags, void *private, size_t done_before); |
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struct iomap_dio *__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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unsigned int dio_flags, void *private, size_t done_before); |
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ssize_t iomap_dio_complete(struct iomap_dio *dio); |
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void iomap_dio_bio_end_io(struct bio *bio); |
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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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