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       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                 :            : #include <linux/blkdev.h>
      11                 :            : 
      12                 :            : struct address_space;
      13                 :            : struct fiemap_extent_info;
      14                 :            : struct inode;
      15                 :            : struct iov_iter;
      16                 :            : struct kiocb;
      17                 :            : struct page;
      18                 :            : struct vm_area_struct;
      19                 :            : struct vm_fault;
      20                 :            : 
      21                 :            : /*
      22                 :            :  * Types of block ranges for iomap mappings:
      23                 :            :  */
      24                 :            : #define IOMAP_HOLE      0x01    /* no blocks allocated, need allocation */
      25                 :            : #define IOMAP_DELALLOC  0x02    /* delayed allocation blocks */
      26                 :            : #define IOMAP_MAPPED    0x03    /* blocks allocated at @addr */
      27                 :            : #define IOMAP_UNWRITTEN 0x04    /* blocks allocated at @addr in unwritten state */
      28                 :            : #define IOMAP_INLINE    0x05    /* data inline in the inode */
      29                 :            : 
      30                 :            : /*
      31                 :            :  * Flags for all iomap mappings:
      32                 :            :  *
      33                 :            :  * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
      34                 :            :  * written data and requires fdatasync to commit them to persistent storage.
      35                 :            :  */
      36                 :            : #define IOMAP_F_NEW             0x01    /* blocks have been newly allocated */
      37                 :            : #define IOMAP_F_DIRTY           0x02    /* uncommitted metadata */
      38                 :            : #define IOMAP_F_BUFFER_HEAD     0x04    /* file system requires buffer heads */
      39                 :            : #define IOMAP_F_SIZE_CHANGED    0x08    /* file size has changed */
      40                 :            : 
      41                 :            : /*
      42                 :            :  * Flags that only need to be reported for IOMAP_REPORT requests:
      43                 :            :  */
      44                 :            : #define IOMAP_F_MERGED          0x10    /* contains multiple blocks/extents */
      45                 :            : #define IOMAP_F_SHARED          0x20    /* block shared with another file */
      46                 :            : 
      47                 :            : /*
      48                 :            :  * Flags from 0x1000 up are for file system specific usage:
      49                 :            :  */
      50                 :            : #define IOMAP_F_PRIVATE         0x1000
      51                 :            : 
      52                 :            : 
      53                 :            : /*
      54                 :            :  * Magic value for addr:
      55                 :            :  */
      56                 :            : #define IOMAP_NULL_ADDR -1ULL   /* addr is not valid */
      57                 :            : 
      58                 :            : struct iomap_page_ops;
      59                 :            : 
      60                 :            : struct iomap {
      61                 :            :         u64                     addr; /* disk offset of mapping, bytes */
      62                 :            :         loff_t                  offset; /* file offset of mapping, bytes */
      63                 :            :         u64                     length; /* length of mapping, bytes */
      64                 :            :         u16                     type;   /* type of mapping */
      65                 :            :         u16                     flags;  /* flags for mapping */
      66                 :            :         struct block_device     *bdev;  /* block device for I/O */
      67                 :            :         struct dax_device       *dax_dev; /* dax_dev for dax operations */
      68                 :            :         void                    *inline_data;
      69                 :            :         void                    *private; /* filesystem private */
      70                 :            :         const struct iomap_page_ops *page_ops;
      71                 :            : };
      72                 :            : 
      73                 :            : static inline sector_t
      74                 :            : iomap_sector(struct iomap *iomap, loff_t pos)
      75                 :            : {
      76                 :          0 :         return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
      77                 :            : }
      78                 :            : 
      79                 :            : /*
      80                 :            :  * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
      81                 :            :  * and page_done will be called for each page written to.  This only applies to
      82                 :            :  * buffered writes as unbuffered writes will not typically have pages
      83                 :            :  * associated with them.
      84                 :            :  *
      85                 :            :  * When page_prepare succeeds, page_done will always be called to do any
      86                 :            :  * cleanup work necessary.  In that page_done call, @page will be NULL if the
      87                 :            :  * associated page could not be obtained.
      88                 :            :  */
      89                 :            : struct iomap_page_ops {
      90                 :            :         int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,
      91                 :            :                         struct iomap *iomap);
      92                 :            :         void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
      93                 :            :                         struct page *page, struct iomap *iomap);
      94                 :            : };
      95                 :            : 
      96                 :            : /*
      97                 :            :  * Flags for iomap_begin / iomap_end.  No flag implies a read.
      98                 :            :  */
      99                 :            : #define IOMAP_WRITE             (1 << 0) /* writing, must allocate blocks */
     100                 :            : #define IOMAP_ZERO              (1 << 1) /* zeroing operation, may skip holes */
     101                 :            : #define IOMAP_REPORT            (1 << 2) /* report extent status, e.g. FIEMAP */
     102                 :            : #define IOMAP_FAULT             (1 << 3) /* mapping for page fault */
     103                 :            : #define IOMAP_DIRECT            (1 << 4) /* direct I/O */
     104                 :            : #define IOMAP_NOWAIT            (1 << 5) /* do not block */
     105                 :            : 
     106                 :            : struct iomap_ops {
     107                 :            :         /*
     108                 :            :          * Return the existing mapping at pos, or reserve space starting at
     109                 :            :          * pos for up to length, as long as we can do it as a single mapping.
     110                 :            :          * The actual length is returned in iomap->length.
     111                 :            :          */
     112                 :            :         int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
     113                 :            :                         unsigned flags, struct iomap *iomap);
     114                 :            : 
     115                 :            :         /*
     116                 :            :          * Commit and/or unreserve space previous allocated using iomap_begin.
     117                 :            :          * Written indicates the length of the successful write operation which
     118                 :            :          * needs to be commited, while the rest needs to be unreserved.
     119                 :            :          * Written might be zero if no data was written.
     120                 :            :          */
     121                 :            :         int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
     122                 :            :                         ssize_t written, unsigned flags, struct iomap *iomap);
     123                 :            : };
     124                 :            : 
     125                 :            : /*
     126                 :            :  * Main iomap iterator function.
     127                 :            :  */
     128                 :            : typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
     129                 :            :                 void *data, struct iomap *iomap);
     130                 :            : 
     131                 :            : loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
     132                 :            :                 unsigned flags, const struct iomap_ops *ops, void *data,
     133                 :            :                 iomap_actor_t actor);
     134                 :            : 
     135                 :            : /*
     136                 :            :  * Structure allocate for each page when block size < PAGE_SIZE to track
     137                 :            :  * sub-page uptodate status and I/O completions.
     138                 :            :  */
     139                 :            : struct iomap_page {
     140                 :            :         atomic_t                read_count;
     141                 :            :         atomic_t                write_count;
     142                 :            :         DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
     143                 :            : };
     144                 :            : 
     145                 :            : static inline struct iomap_page *to_iomap_page(struct page *page)
     146                 :            : {
     147                 :          0 :         if (page_has_private(page))
     148                 :          0 :                 return (struct iomap_page *)page_private(page);
     149                 :            :         return NULL;
     150                 :            : }
     151                 :            : 
     152                 :            : ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
     153                 :            :                 const struct iomap_ops *ops);
     154                 :            : int iomap_readpage(struct page *page, const struct iomap_ops *ops);
     155                 :            : int iomap_readpages(struct address_space *mapping, struct list_head *pages,
     156                 :            :                 unsigned nr_pages, const struct iomap_ops *ops);
     157                 :            : int iomap_set_page_dirty(struct page *page);
     158                 :            : int iomap_is_partially_uptodate(struct page *page, unsigned long from,
     159                 :            :                 unsigned long count);
     160                 :            : int iomap_releasepage(struct page *page, gfp_t gfp_mask);
     161                 :            : void iomap_invalidatepage(struct page *page, unsigned int offset,
     162                 :            :                 unsigned int len);
     163                 :            : #ifdef CONFIG_MIGRATION
     164                 :            : int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
     165                 :            :                 struct page *page, enum migrate_mode mode);
     166                 :            : #else
     167                 :            : #define iomap_migrate_page NULL
     168                 :            : #endif
     169                 :            : int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
     170                 :            :                 const struct iomap_ops *ops);
     171                 :            : int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
     172                 :            :                 bool *did_zero, const struct iomap_ops *ops);
     173                 :            : int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
     174                 :            :                 const struct iomap_ops *ops);
     175                 :            : vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
     176                 :            :                         const struct iomap_ops *ops);
     177                 :            : int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
     178                 :            :                 loff_t start, loff_t len, const struct iomap_ops *ops);
     179                 :            : loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
     180                 :            :                 const struct iomap_ops *ops);
     181                 :            : loff_t iomap_seek_data(struct inode *inode, loff_t offset,
     182                 :            :                 const struct iomap_ops *ops);
     183                 :            : sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
     184                 :            :                 const struct iomap_ops *ops);
     185                 :            : 
     186                 :            : /*
     187                 :            :  * Flags for direct I/O ->end_io:
     188                 :            :  */
     189                 :            : #define IOMAP_DIO_UNWRITTEN     (1 << 0)  /* covers unwritten extent(s) */
     190                 :            : #define IOMAP_DIO_COW           (1 << 1)  /* covers COW extent(s) */
     191                 :            : 
     192                 :            : struct iomap_dio_ops {
     193                 :            :         int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
     194                 :            :                       unsigned flags);
     195                 :            : };
     196                 :            : 
     197                 :            : ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
     198                 :            :                 const struct iomap_ops *ops, const struct iomap_dio_ops *dops);
     199                 :            : int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
     200                 :            : 
     201                 :            : #ifdef CONFIG_SWAP
     202                 :            : struct file;
     203                 :            : struct swap_info_struct;
     204                 :            : 
     205                 :            : int iomap_swapfile_activate(struct swap_info_struct *sis,
     206                 :            :                 struct file *swap_file, sector_t *pagespan,
     207                 :            :                 const struct iomap_ops *ops);
     208                 :            : #else
     209                 :            : # define iomap_swapfile_activate(sis, swapfile, pagespan, ops)  (-EIO)
     210                 :            : #endif /* CONFIG_SWAP */
     211                 :            : 
     212                 :            : #endif /* LINUX_IOMAP_H */