FreeBSD/Linux Kernel Cross Reference
sys/fs/ext2fs/ext2_extents.h

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2012, 2010 Zheng Liu <lz@freebsd.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    #ifndef _FS_EXT2FS_EXT2_EXTENTS_H_
    #define _FS_EXT2FS_EXT2_EXTENTS_H_
    
    #include <sys/types.h>
    
    #define EXT4_EXT_MAGIC  0xf30a
    #define EXT4_MAX_BLOCKS 0xffffffff
    #define EXT_INIT_MAX_LEN (1UL << 15)
    #define EXT4_MAX_LEN    (EXT_INIT_MAX_LEN - 1)
    #define EXT4_EXT_DEPTH_MAX 5
    
    #define EXT4_EXT_CACHE_NO       0
    #define EXT4_EXT_CACHE_GAP      1
    #define EXT4_EXT_CACHE_IN       2
    
    /*
     * Ext4 extent tail with csum
     */
    struct ext4_extent_tail {
            uint32_t et_checksum;   /* crc32c(uuid+inum+extent_block) */
    };
    
    /*
     * Ext4 file system extent on disk.
     */
    struct ext4_extent {
            uint32_t e_blk;                 /* first logical block */
            uint16_t e_len;                 /* number of blocks */
            uint16_t e_start_hi;            /* high 16 bits of physical block */
            uint32_t e_start_lo;            /* low 32 bits of physical block */
    };
    
    /*
     * Extent index on disk.
     */
    struct ext4_extent_index {
            uint32_t ei_blk;        /* indexes logical blocks */
            uint32_t ei_leaf_lo;    /* points to physical block of the
                                     * next level */
            uint16_t ei_leaf_hi;    /* high 16 bits of physical block */
            uint16_t ei_unused;
    };
    
    /*
     * Extent tree header.
     */
    struct ext4_extent_header {
            uint16_t eh_magic;              /* magic number: 0xf30a */
            uint16_t eh_ecount;             /* number of valid entries */
            uint16_t eh_max;                /* capacity of store in entries */
            uint16_t eh_depth;              /* the depth of extent tree */
            uint32_t eh_gen;                /* generation of extent tree */
    };
    
    /*
     * Save cached extent.
     */
    struct ext4_extent_cache {
            daddr_t ec_start;               /* extent start */
            uint32_t ec_blk;                /* logical block */
            uint32_t ec_len;
            uint32_t ec_type;
    };
    
    /*
     * Save path to some extent.
     */
    struct ext4_extent_path {
            int index_count;
            uint16_t ep_depth;
           uint64_t ep_blk;
           char *ep_data;
           struct ext4_extent *ep_ext;
           struct ext4_extent_index *ep_index;
           struct ext4_extent_header *ep_header;
   };
   
   #define EXT_FIRST_EXTENT(hdr) ((struct ext4_extent *)(((char *)(hdr)) + \
       sizeof(struct ext4_extent_header)))
   #define EXT_FIRST_INDEX(hdr) ((struct ext4_extent_index *)(((char *)(hdr)) + \
       sizeof(struct ext4_extent_header)))
   #define EXT_LAST_EXTENT(hdr) (EXT_FIRST_EXTENT((hdr)) + le16toh((hdr)->eh_ecount) - 1)
   #define EXT_LAST_INDEX(hdr) (EXT_FIRST_INDEX((hdr)) + le16toh((hdr)->eh_ecount) - 1)
   #define EXT4_EXTENT_TAIL_OFFSET(hdr) (sizeof(struct ext4_extent_header) + \
       (sizeof(struct ext4_extent) * le16toh((hdr)->eh_max)))
   #define EXT_HAS_FREE_INDEX(path) \
       (le16toh((path)->ep_header->eh_ecount) < le16toh((path)->ep_header->eh_max))
   #define EXT_MAX_EXTENT(hdr) (EXT_FIRST_EXTENT(hdr) + le16toh((hdr)->eh_max) - 1)
   #define EXT_MAX_INDEX(hdr) (EXT_FIRST_INDEX((hdr)) + le16toh((hdr)->eh_max) - 1)
   
   struct inode;
   struct m_ext2fs;
   void    ext4_ext_tree_init(struct inode *ip);
   int     ext4_ext_in_cache(struct inode *, daddr_t, struct ext4_extent *);
   void    ext4_ext_put_cache(struct inode *, struct ext4_extent *, int);
   int ext4_ext_find_extent(struct inode *, daddr_t, struct ext4_extent_path **);
   void ext4_ext_path_free(struct ext4_extent_path *path);
   int ext4_ext_remove_space(struct inode *ip, off_t length, int flags,
       struct ucred *cred, struct thread *td);
   int ext4_ext_get_blocks(struct inode *ip, int64_t iblock,
       unsigned long max_blocks, struct ucred *cred, struct buf **bpp,
       int *allocate, daddr_t *);
   #ifdef EXT2FS_PRINT_EXTENTS
   void ext4_ext_print_extent_tree_status(struct inode *ip);
   #endif
   
   #endif  /* !_FS_EXT2FS_EXT2_EXTENTS_H_ */

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