include/linux/iomap.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef LINUX_IOMAP_H
   3 #define LINUX_IOMAP_H 1
   4
   5 #include <linux/atomic.h>
   6 #include <linux/bitmap.h>
   7 #include <linux/mm.h>
   8 #include <linux/types.h>
   9 #include <linux/mm_types.h>
  10
  11 struct address_space;
  12 struct fiemap_extent_info;
  13 struct inode;
  14 struct iov_iter;
  15 struct kiocb;
  16 struct page;
  17 struct vm_area_struct;
  18 struct vm_fault;
  19
  20 /*
  21  * Types of block ranges for iomap mappings:
  22  */
  23 #define IOMAP_HOLE      0x01    /* no blocks allocated, need allocation */
  24 #define IOMAP_DELALLOC  0x02    /* delayed allocation blocks */
  25 #define IOMAP_MAPPED    0x03    /* blocks allocated at @addr */
  26 #define IOMAP_UNWRITTEN 0x04    /* blocks allocated at @addr in unwritten state */
  27 #define IOMAP_INLINE    0x05    /* data inline in the inode */
  28
  29 /*
  30  * Flags for all iomap mappings:
  31  *
  32  * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
  33  * written data and requires fdatasync to commit them to persistent storage.
  34  */
  35 #define IOMAP_F_NEW             0x01    /* blocks have been newly allocated */
  36 #define IOMAP_F_DIRTY           0x02    /* uncommitted metadata */
  37 #define IOMAP_F_BUFFER_HEAD     0x04    /* file system requires buffer heads */
  38
  39 /*
  40  * Flags that only need to be reported for IOMAP_REPORT requests:
  41  */
  42 #define IOMAP_F_MERGED          0x10    /* contains multiple blocks/extents */
  43 #define IOMAP_F_SHARED          0x20    /* block shared with another file */
  44
  45 /*
  46  * Flags from 0x1000 up are for file system specific usage:
  47  */
  48 #define IOMAP_F_PRIVATE         0x1000
  49
  50
  51 /*
  52  * Magic value for addr:
  53  */
  54 #define IOMAP_NULL_ADDR -1ULL   /* addr is not valid */
  55
  56 struct iomap_page_ops;
  57
  58 struct iomap {
  59         u64                     addr; /* disk offset of mapping, bytes */
  60         loff_t                  offset; /* file offset of mapping, bytes */
  61         u64                     length; /* length of mapping, bytes */
  62         u16                     type;   /* type of mapping */
  63         u16                     flags;  /* flags for mapping */
  64         struct block_device     *bdev;  /* block device for I/O */
  65         struct dax_device       *dax_dev; /* dax_dev for dax operations */
  66         void                    *inline_data;
  67         void                    *private; /* filesystem private */
  68         const struct iomap_page_ops *page_ops;
  69 };
  70
  71 /*
  72  * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
  73  * and page_done will be called for each page written to.  This only applies to
  74  * buffered writes as unbuffered writes will not typically have pages
  75  * associated with them.
  76  *
  77  * When page_prepare succeeds, page_done will always be called to do any
  78  * cleanup work necessary.  In that page_done call, @page will be NULL if the
  79  * associated page could not be obtained.
  80  */
  81 struct iomap_page_ops {
  82         int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,
  83                         struct iomap *iomap);
  84         void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
  85                         struct page *page, struct iomap *iomap);
  86 };
  87
  88 /*
  89  * Flags for iomap_begin / iomap_end.  No flag implies a read.
  90  */
  91 #define IOMAP_WRITE             (1 << 0) /* writing, must allocate blocks */
  92 #define IOMAP_ZERO              (1 << 1) /* zeroing operation, may skip holes */
  93 #define IOMAP_REPORT            (1 << 2) /* report extent status, e.g. FIEMAP */
  94 #define IOMAP_FAULT             (1 << 3) /* mapping for page fault */
  95 #define IOMAP_DIRECT            (1 << 4) /* direct I/O */
  96 #define IOMAP_NOWAIT            (1 << 5) /* do not block */
  97
  98 struct iomap_ops {
  99         /*
 100          * Return the existing mapping at pos, or reserve space starting at
 101          * pos for up to length, as long as we can do it as a single mapping.
 102          * The actual length is returned in iomap->length.
 103          */
 104         int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
 105                         unsigned flags, struct iomap *iomap);
 106
 107         /*
 108          * Commit and/or unreserve space previous allocated using iomap_begin.
 109          * Written indicates the length of the successful write operation which
 110          * needs to be commited, while the rest needs to be unreserved.
 111          * Written might be zero if no data was written.
 112          */
 113         int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
 114                         ssize_t written, unsigned flags, struct iomap *iomap);
 115 };
 116
 117 /*
 118  * Structure allocate for each page when block size < PAGE_SIZE to track
 119  * sub-page uptodate status and I/O completions.
 120  */
 121 struct iomap_page {
 122         atomic_t                read_count;
 123         atomic_t                write_count;
 124         DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
 125 };
 126
 127 static inline struct iomap_page *to_iomap_page(struct page *page)
 128 {
 129         if (page_has_private(page))
 130                 return (struct iomap_page *)page_private(page);
 131         return NULL;
 132 }
 133
 134 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
 135                 const struct iomap_ops *ops);
 136 int iomap_readpage(struct page *page, const struct iomap_ops *ops);
 137 int iomap_readpages(struct address_space *mapping, struct list_head *pages,
 138                 unsigned nr_pages, const struct iomap_ops *ops);
 139 int iomap_set_page_dirty(struct page *page);
 140 int iomap_is_partially_uptodate(struct page *page, unsigned long from,
 141                 unsigned long count);
 142 int iomap_releasepage(struct page *page, gfp_t gfp_mask);
 143 void iomap_invalidatepage(struct page *page, unsigned int offset,
 144                 unsigned int len);
 145 #ifdef CONFIG_MIGRATION
 146 int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
 147                 struct page *page, enum migrate_mode mode);
 148 #else
 149 #define iomap_migrate_page NULL
 150 #endif
 151 int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
 152                 const struct iomap_ops *ops);
 153 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
 154                 bool *did_zero, const struct iomap_ops *ops);
 155 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
 156                 const struct iomap_ops *ops);
 157 vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
 158                         const struct iomap_ops *ops);
 159 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 160                 loff_t start, loff_t len, const struct iomap_ops *ops);
 161 loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
 162                 const struct iomap_ops *ops);
 163 loff_t iomap_seek_data(struct inode *inode, loff_t offset,
 164                 const struct iomap_ops *ops);
 165 sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
 166                 const struct iomap_ops *ops);
 167
 168 /*
 169  * Flags for direct I/O ->end_io:
 170  */
 171 #define IOMAP_DIO_UNWRITTEN     (1 << 0)        /* covers unwritten extent(s) */
 172 #define IOMAP_DIO_COW           (1 << 1)        /* covers COW extent(s) */
 173 typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
 174                 unsigned flags);
 175 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 176                 const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
 177 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
 178
 179 #ifdef CONFIG_SWAP
 180 struct file;
 181 struct swap_info_struct;
 182
 183 int iomap_swapfile_activate(struct swap_info_struct *sis,
 184                 struct file *swap_file, sector_t *pagespan,
 185                 const struct iomap_ops *ops);
 186 #else
 187 # define iomap_swapfile_activate(sis, swapfile, pagespan, ops)  (-EIO)
 188 #endif /* CONFIG_SWAP */
 189
 190 #endif /* LINUX_IOMAP_H */