diff options
Diffstat (limited to 'include/linux/iomap.h')
| -rw-r--r-- | include/linux/iomap.h | 559 |
1 files changed, 535 insertions, 24 deletions
diff --git a/include/linux/iomap.h b/include/linux/iomap.h index f64dc6ce5161..520e967cb501 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -1,47 +1,183 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef LINUX_IOMAP_H #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> +#include <linux/pagevec.h> +struct address_space; struct fiemap_extent_info; struct inode; +struct iomap_iter; +struct iomap_dio; +struct iomap_writepage_ctx; +struct iomap_read_folio_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 0x01 /* no blocks allocated, need allocation */ -#define IOMAP_DELALLOC 0x02 /* delayed allocation blocks */ -#define IOMAP_MAPPED 0x03 /* blocks allocated @blkno */ -#define IOMAP_UNWRITTEN 0x04 /* blocks allocated @blkno in unwritten state */ +#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 for all iomap mappings: + * 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. + * + * IOMAP_F_XATTR indicates that the iomap is for an extended attribute extent + * rather than a file data extent. + * + * IOMAP_F_BOUNDARY indicates that I/O and I/O completions for this iomap must + * never be merged with the mapping before it. + * + * IOMAP_F_ANON_WRITE indicates that (write) I/O does not have a target block + * assigned to it yet and the file system will do that in the bio submission + * handler, splitting the I/O as needed. + * + * IOMAP_F_ATOMIC_BIO indicates that (write) I/O will be issued as an atomic + * bio, i.e. set REQ_ATOMIC. */ -#define IOMAP_F_NEW 0x01 /* blocks have been newly allocated */ +#define IOMAP_F_NEW (1U << 0) +#define IOMAP_F_DIRTY (1U << 1) +#define IOMAP_F_SHARED (1U << 2) +#define IOMAP_F_MERGED (1U << 3) +#ifdef CONFIG_BUFFER_HEAD +#define IOMAP_F_BUFFER_HEAD (1U << 4) +#else +#define IOMAP_F_BUFFER_HEAD 0 +#endif /* CONFIG_BUFFER_HEAD */ +#define IOMAP_F_XATTR (1U << 5) +#define IOMAP_F_BOUNDARY (1U << 6) +#define IOMAP_F_ANON_WRITE (1U << 7) +#define IOMAP_F_ATOMIC_BIO (1U << 8) /* - * Flags that only need to be reported for IOMAP_REPORT requests: + * Flag reserved for file system specific usage */ -#define IOMAP_F_MERGED 0x10 /* contains multiple blocks/extents */ -#define IOMAP_F_SHARED 0x20 /* block shared with another file */ +#define IOMAP_F_PRIVATE (1U << 12) /* - * Magic value for blkno: + * 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. + * + * IOMAP_F_STALE indicates that the iomap is not valid any longer and the file + * range it covers needs to be remapped by the high level before the operation + * can proceed. */ -#define IOMAP_NULL_BLOCK -1LL /* blkno is not valid */ +#define IOMAP_F_SIZE_CHANGED (1U << 14) +#define IOMAP_F_STALE (1U << 15) + +/* + * Magic value for addr: + */ +#define IOMAP_NULL_ADDR -1ULL /* addr is not valid */ struct iomap { - sector_t blkno; /* 1st sector of mapping, 512b units */ + 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 */ + u64 validity_cookie; /* used with .iomap_valid() */ +}; + +static inline sector_t iomap_sector(const struct iomap *iomap, loff_t pos) +{ + if (iomap->flags & IOMAP_F_ANON_WRITE) + return U64_MAX; /* invalid */ + return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; +} + +/* + * Returns the inline data pointer for logical offset @pos. + */ +static inline void *iomap_inline_data(const struct iomap *iomap, loff_t pos) +{ + return iomap->inline_data + pos - iomap->offset; +} + +/* + * Check if the mapping's length is within the valid range for inline data. + * This is used to guard against accessing data beyond the page inline_data + * points at. + */ +static inline bool iomap_inline_data_valid(const struct iomap *iomap) +{ + return iomap->length <= PAGE_SIZE - offset_in_page(iomap->inline_data); +} + +/* + * When get_folio succeeds, put_folio will always be called to do any + * cleanup work necessary. put_folio is responsible for unlocking and putting + * @folio. + */ +struct iomap_write_ops { + struct folio *(*get_folio)(struct iomap_iter *iter, loff_t pos, + unsigned len); + void (*put_folio)(struct inode *inode, loff_t pos, unsigned copied, + struct folio *folio); + + /* + * Check that the cached iomap still maps correctly to the filesystem's + * internal extent map. FS internal extent maps can change while iomap + * is iterating a cached iomap, so this hook allows iomap to detect that + * the iomap needs to be refreshed during a long running write + * operation. + * + * The filesystem can store internal state (e.g. a sequence number) in + * iomap->validity_cookie when the iomap is first mapped to be able to + * detect changes between mapping time and whenever .iomap_valid() is + * called. + * + * This is called with the folio over the specified file position held + * locked by the iomap code. + */ + bool (*iomap_valid)(struct inode *inode, const struct iomap *iomap); + + /* + * Optional if the filesystem wishes to provide a custom handler for + * reading in the contents of a folio, otherwise iomap will default to + * submitting a bio read request. + * + * The read must be done synchronously. + */ + int (*read_folio_range)(const struct iomap_iter *iter, + struct folio *folio, loff_t pos, size_t len); }; /* @@ -52,7 +188,16 @@ struct iomap { #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) /* Don't wait for writeback */ +#define IOMAP_NOWAIT (1 << 5) /* do not block */ +#define IOMAP_OVERWRITE_ONLY (1 << 6) /* only pure overwrites allowed */ +#define IOMAP_UNSHARE (1 << 7) /* unshare_file_range */ +#ifdef CONFIG_FS_DAX +#define IOMAP_DAX (1 << 8) /* DAX mapping */ +#else +#define IOMAP_DAX 0 +#endif /* CONFIG_FS_DAX */ +#define IOMAP_ATOMIC (1 << 9) /* torn-write protection */ +#define IOMAP_DONTCACHE (1 << 10) struct iomap_ops { /* @@ -61,7 +206,8 @@ struct iomap_ops { * 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); + unsigned flags, struct iomap *iomap, + struct iomap *srcmap); /* * Commit and/or unreserve space previous allocated using iomap_begin. @@ -73,30 +219,395 @@ struct iomap_ops { ssize_t written, unsigned flags, struct iomap *iomap); }; +/** + * struct iomap_iter - Iterate through a range of a file + * @inode: Set at the start of the iteration and should not change. + * @pos: The current file position we are operating on. It is updated by + * calls to iomap_iter(). Treat as read-only in the body. + * @len: The remaining length of the file segment we're operating on. + * It is updated at the same time as @pos. + * @iter_start_pos: The original start pos for the current iomap. Used for + * incremental iter advance. + * @status: Status of the most recent iteration. Zero on success or a negative + * errno on error. + * @flags: Zero or more of the iomap_begin flags above. + * @iomap: Map describing the I/O iteration + * @srcmap: Source map for COW operations + */ +struct iomap_iter { + struct inode *inode; + loff_t pos; + u64 len; + loff_t iter_start_pos; + int status; + unsigned flags; + struct iomap iomap; + struct iomap srcmap; + struct folio_batch *fbatch; + void *private; +}; + +int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops); +int iomap_iter_advance(struct iomap_iter *iter, u64 count); + +/** + * iomap_length_trim - trimmed length of the current iomap iteration + * @iter: iteration structure + * @pos: File position to trim from. + * @len: Length of the mapping to trim to. + * + * Returns a trimmed length that the operation applies to for the current + * iteration. + */ +static inline u64 iomap_length_trim(const struct iomap_iter *iter, loff_t pos, + u64 len) +{ + u64 end = iter->iomap.offset + iter->iomap.length; + + if (iter->srcmap.type != IOMAP_HOLE) + end = min(end, iter->srcmap.offset + iter->srcmap.length); + return min(len, end - pos); +} + +/** + * iomap_length - length of the current iomap iteration + * @iter: iteration structure + * + * Returns the length that the operation applies to for the current iteration. + */ +static inline u64 iomap_length(const struct iomap_iter *iter) +{ + return iomap_length_trim(iter, iter->pos, iter->len); +} + +/** + * iomap_iter_advance_full - advance by the full length of current map + */ +static inline int iomap_iter_advance_full(struct iomap_iter *iter) +{ + return iomap_iter_advance(iter, iomap_length(iter)); +} + +/** + * iomap_iter_srcmap - return the source map for the current iomap iteration + * @i: iteration structure + * + * Write operations on file systems with reflink support might require a + * source and a destination map. This function retourns the source map + * for a given operation, which may or may no be identical to the destination + * map in &i->iomap. + */ +static inline const struct iomap *iomap_iter_srcmap(const struct iomap_iter *i) +{ + if (i->srcmap.type != IOMAP_HOLE) + return &i->srcmap; + return &i->iomap; +} + +/* + * Return the file offset for the first unchanged block after a short write. + * + * If nothing was written, round @pos down to point at the first block in + * the range, else round up to include the partially written block. + */ +static inline loff_t iomap_last_written_block(struct inode *inode, loff_t pos, + ssize_t written) +{ + if (unlikely(!written)) + return round_down(pos, i_blocksize(inode)); + return round_up(pos + written, i_blocksize(inode)); +} + +/* + * Check if the range needs to be unshared for a FALLOC_FL_UNSHARE_RANGE + * operation. + * + * Don't bother with blocks that are not shared to start with; or mappings that + * cannot be shared, such as inline data, delalloc reservations, holes or + * unwritten extents. + * + * Note that we use srcmap directly instead of iomap_iter_srcmap as unsharing + * requires providing a separate source map, and the presence of one is a good + * indicator that unsharing is needed, unlike IOMAP_F_SHARED which can be set + * for any data that goes into the COW fork for XFS. + */ +static inline bool iomap_want_unshare_iter(const struct iomap_iter *iter) +{ + return (iter->iomap.flags & IOMAP_F_SHARED) && + iter->srcmap.type == IOMAP_MAPPED; +} + ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from, - const struct iomap_ops *ops); -int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len, - const struct iomap_ops *ops); + const struct iomap_ops *ops, + const struct iomap_write_ops *write_ops, void *private); +void iomap_read_folio(const struct iomap_ops *ops, + struct iomap_read_folio_ctx *ctx); +void iomap_readahead(const struct iomap_ops *ops, + struct iomap_read_folio_ctx *ctx); +bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count); +struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len); +bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags); +void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len); +bool iomap_dirty_folio(struct address_space *mapping, struct folio *folio); +int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, + const struct iomap_ops *ops, + const struct iomap_write_ops *write_ops); +loff_t iomap_fill_dirty_folios(struct iomap_iter *iter, loff_t offset, + loff_t length); int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, - bool *did_zero, const struct iomap_ops *ops); + bool *did_zero, const struct iomap_ops *ops, + const struct iomap_write_ops *write_ops, void *private); int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, - const struct iomap_ops *ops); -int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops); + const struct iomap_ops *ops, + const struct iomap_write_ops *write_ops, void *private); +vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops, + void *private); +typedef void (*iomap_punch_t)(struct inode *inode, loff_t offset, loff_t length, + struct iomap *iomap); +void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, + loff_t end_byte, unsigned flags, struct iomap *iomap, + iomap_punch_t punch); + int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, - loff_t start, loff_t len, const struct iomap_ops *ops); + 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); + +/* + * Flags for iomap_ioend->io_flags. + */ +/* shared COW extent */ +#define IOMAP_IOEND_SHARED (1U << 0) +/* unwritten extent */ +#define IOMAP_IOEND_UNWRITTEN (1U << 1) +/* don't merge into previous ioend */ +#define IOMAP_IOEND_BOUNDARY (1U << 2) +/* is direct I/O */ +#define IOMAP_IOEND_DIRECT (1U << 3) +/* is DONTCACHE I/O */ +#define IOMAP_IOEND_DONTCACHE (1U << 4) + +/* + * Flags that if set on either ioend prevent the merge of two ioends. + * (IOMAP_IOEND_BOUNDARY also prevents merges, but only one-way) + */ +#define IOMAP_IOEND_NOMERGE_FLAGS \ + (IOMAP_IOEND_SHARED | IOMAP_IOEND_UNWRITTEN | IOMAP_IOEND_DIRECT | \ + IOMAP_IOEND_DONTCACHE) + +/* + * Structure for writeback I/O completions. + * + * File systems can split a bio generated by iomap. In that case the parent + * ioend it was split from is recorded in ioend->io_parent. + */ +struct iomap_ioend { + struct list_head io_list; /* next ioend in chain */ + u16 io_flags; /* IOMAP_IOEND_* */ + struct inode *io_inode; /* file being written to */ + size_t io_size; /* size of the extent */ + atomic_t io_remaining; /* completetion defer count */ + int io_error; /* stashed away status */ + struct iomap_ioend *io_parent; /* parent for completions */ + loff_t io_offset; /* offset in the file */ + sector_t io_sector; /* start sector of ioend */ + void *io_private; /* file system private data */ + struct bio io_bio; /* MUST BE LAST! */ +}; + +static inline struct iomap_ioend *iomap_ioend_from_bio(struct bio *bio) +{ + return container_of(bio, struct iomap_ioend, io_bio); +} + +struct iomap_writeback_ops { + /* + * Performs writeback on the passed in range + * + * Can map arbitrarily large regions, but we need to call into it at + * least once per folio to allow the file systems to synchronize with + * the write path that could be invalidating mappings. + * + * An existing mapping from a previous call to this method can be reused + * by the file system if it is still valid. + * + * If this succeeds, iomap_finish_folio_write() must be called once + * writeback completes for the range, regardless of whether the + * writeback succeeded or failed. + * + * Returns the number of bytes processed or a negative errno. + */ + ssize_t (*writeback_range)(struct iomap_writepage_ctx *wpc, + struct folio *folio, u64 pos, unsigned int len, + u64 end_pos); + + /* + * Submit a writeback context previously build up by ->writeback_range. + * + * Returns 0 if the context was successfully submitted, or a negative + * error code if not. If @error is non-zero a failure occurred, and + * the writeback context should be completed with an error. + */ + int (*writeback_submit)(struct iomap_writepage_ctx *wpc, int error); +}; + +struct iomap_writepage_ctx { + struct iomap iomap; + struct inode *inode; + struct writeback_control *wbc; + const struct iomap_writeback_ops *ops; + u32 nr_folios; /* folios added to the ioend */ + void *wb_ctx; /* pending writeback context */ +}; + +struct iomap_ioend *iomap_init_ioend(struct inode *inode, struct bio *bio, + loff_t file_offset, u16 ioend_flags); +struct iomap_ioend *iomap_split_ioend(struct iomap_ioend *ioend, + unsigned int max_len, bool is_append); +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 iomap_sort_ioends(struct list_head *ioend_list); +ssize_t iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct folio *folio, + loff_t pos, loff_t end_pos, unsigned int dirty_len); +int iomap_ioend_writeback_submit(struct iomap_writepage_ctx *wpc, int error); + +void iomap_finish_folio_read(struct folio *folio, size_t off, size_t len, + int error); +void iomap_finish_folio_write(struct inode *inode, struct folio *folio, + size_t len); + +int iomap_writeback_folio(struct iomap_writepage_ctx *wpc, struct folio *folio); +int iomap_writepages(struct iomap_writepage_ctx *wpc); + +struct iomap_read_folio_ctx { + const struct iomap_read_ops *ops; + struct folio *cur_folio; + struct readahead_control *rac; + void *read_ctx; +}; + +struct iomap_read_ops { + /* + * Read in a folio range. + * + * If this succeeds, iomap_finish_folio_read() must be called after the + * range is read in, regardless of whether the read succeeded or failed. + * + * Returns 0 on success or a negative error on failure. + */ + int (*read_folio_range)(const struct iomap_iter *iter, + struct iomap_read_folio_ctx *ctx, size_t len); + + /* + * Submit any pending read requests. + * + * This is optional. + */ + void (*submit_read)(struct iomap_read_folio_ctx *ctx); +}; /* * 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) */ -typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret, - unsigned flags); + +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) + +/* + * Ensure each bio is aligned to fs block size. + * + * For filesystems which need to calculate/verify the checksum of each fs + * block. Otherwise they may not be able to handle unaligned bios. + */ +#define IOMAP_DIO_FSBLOCK_ALIGNED (1 << 3) + ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, - const struct iomap_ops *ops, iomap_dio_end_io_t end_io); + 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 */ + +extern struct bio_set iomap_ioend_bioset; + +#ifdef CONFIG_BLOCK +extern const struct iomap_read_ops iomap_bio_read_ops; + +static inline void iomap_bio_read_folio(struct folio *folio, + const struct iomap_ops *ops) +{ + struct iomap_read_folio_ctx ctx = { + .ops = &iomap_bio_read_ops, + .cur_folio = folio, + }; + + iomap_read_folio(ops, &ctx); +} + +static inline void iomap_bio_readahead(struct readahead_control *rac, + const struct iomap_ops *ops) +{ + struct iomap_read_folio_ctx ctx = { + .ops = &iomap_bio_read_ops, + .rac = rac, + }; + + iomap_readahead(ops, &ctx); +} +#endif /* CONFIG_BLOCK */ #endif /* LINUX_IOMAP_H */ |