LXR linux/include/linux/ext4_fs

   1/*
   2 *  linux/include/linux/ext4_fs_i.h
   3 *
   4 * Copyright (C) 1992, 1993, 1994, 1995
   5 * Remy Card (card@masi.ibp.fr)
   6 * Laboratoire MASI - Institut Blaise Pascal
   7 * Universite Pierre et Marie Curie (Paris VI)
   8 *
   9 *  from
  10 *
  11 *  linux/include/linux/minix_fs_i.h
  12 *
  13 *  Copyright (C) 1991, 1992  Linus Torvalds
  14 */
  15
  16#ifndef _LINUX_EXT4_FS_I
  17#define _LINUX_EXT4_FS_I
  18
  19#include <linux/rwsem.h>
  20#include <linux/rbtree.h>
  21#include <linux/seqlock.h>
  22#include <linux/mutex.h>
  23
  24/* data type for block offset of block group */
  25typedef int ext4_grpblk_t;
  26
  27/* data type for filesystem-wide blocks number */
  28typedef unsigned long long ext4_fsblk_t;
  29
  30struct ext4_reserve_window {
  31        ext4_fsblk_t    _rsv_start;     /* First byte reserved */
  32        ext4_fsblk_t    _rsv_end;       /* Last byte reserved or 0 */
  33};
  34
  35struct ext4_reserve_window_node {
  36        struct rb_node          rsv_node;
  37        __u32                   rsv_goal_size;
  38        __u32                   rsv_alloc_hit;
  39        struct ext4_reserve_window      rsv_window;
  40};
  41
  42struct ext4_block_alloc_info {
  43        /* information about reservation window */
  44        struct ext4_reserve_window_node rsv_window_node;
  45        /*
  46         * was i_next_alloc_block in ext4_inode_info
  47         * is the logical (file-relative) number of the
  48         * most-recently-allocated block in this file.
  49         * We use this for detecting linearly ascending allocation requests.
  50         */
  51        __u32 last_alloc_logical_block;
  52        /*
  53         * Was i_next_alloc_goal in ext4_inode_info
  54         * is the *physical* companion to i_next_alloc_block.
  55         * it the physical block number of the block which was most-recentl
  56         * allocated to this file.  This give us the goal (target) for the next
  57         * allocation when we detect linearly ascending requests.
  58         */
  59        ext4_fsblk_t last_alloc_physical_block;
  60};
  61
  62#define rsv_start rsv_window._rsv_start
  63#define rsv_end rsv_window._rsv_end
  64
  65/*
  66 * storage for cached extent
  67 */
  68struct ext4_ext_cache {
  69        ext4_fsblk_t    ec_start;
  70        __u32           ec_block;
  71        __u32           ec_len; /* must be 32bit to return holes */
  72        __u32           ec_type;
  73};
  74
  75/*
  76 * third extended file system inode data in memory
  77 */
  78struct ext4_inode_info {
  79        __le32  i_data[15];     /* unconverted */
  80        __u32   i_flags;
  81        ext4_fsblk_t    i_file_acl;
  82        __u32   i_dir_acl;
  83        __u32   i_dtime;
  84
  85        /*
  86         * i_block_group is the number of the block group which contains
  87         * this file's inode.  Constant across the lifetime of the inode,
  88         * it is ued for making block allocation decisions - we try to
  89         * place a file's data blocks near its inode block, and new inodes
  90         * near to their parent directory's inode.
  91         */
  92        __u32   i_block_group;
  93        __u32   i_state;                /* Dynamic state flags for ext4 */
  94
  95        /* block reservation info */
  96        struct ext4_block_alloc_info *i_block_alloc_info;
  97
  98        __u32   i_dir_start_lookup;
  99#ifdef CONFIG_EXT4DEV_FS_XATTR
 100        /*
 101         * Extended attributes can be read independently of the main file
 102         * data. Taking i_mutex even when reading would cause contention
 103         * between readers of EAs and writers of regular file data, so
 104         * instead we synchronize on xattr_sem when reading or changing
 105         * EAs.
 106         */
 107        struct rw_semaphore xattr_sem;
 108#endif
 109#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
 110        struct posix_acl        *i_acl;
 111        struct posix_acl        *i_default_acl;
 112#endif
 113
 114        struct list_head i_orphan;      /* unlinked but open inodes */
 115
 116        /*
 117         * i_disksize keeps track of what the inode size is ON DISK, not
 118         * in memory.  During truncate, i_size is set to the new size by
 119         * the VFS prior to calling ext4_truncate(), but the filesystem won't
 120         * set i_disksize to 0 until the truncate is actually under way.
 121         *
 122         * The intent is that i_disksize always represents the blocks which
 123         * are used by this file.  This allows recovery to restart truncate
 124         * on orphans if we crash during truncate.  We actually write i_disksize
 125         * into the on-disk inode when writing inodes out, instead of i_size.
 126         *
 127         * The only time when i_disksize and i_size may be different is when
 128         * a truncate is in progress.  The only things which change i_disksize
 129         * are ext4_get_block (growth) and ext4_truncate (shrinkth).
 130         */
 131        loff_t  i_disksize;
 132
 133        /* on-disk additional length */
 134        __u16 i_extra_isize;
 135
 136        /*
 137         * truncate_mutex is for serialising ext4_truncate() against
 138         * ext4_getblock().  In the 2.4 ext2 design, great chunks of inode's
 139         * data tree are chopped off during truncate. We can't do that in
 140         * ext4 because whenever we perform intermediate commits during
 141         * truncate, the inode and all the metadata blocks *must* be in a
 142         * consistent state which allows truncation of the orphans to restart
 143         * during recovery.  Hence we must fix the get_block-vs-truncate race
 144         * by other means, so we have truncate_mutex.
 145         */
 146        struct mutex truncate_mutex;
 147        struct inode vfs_inode;
 148
 149        unsigned long i_ext_generation;
 150        struct ext4_ext_cache i_cached_extent;
 151        /*
 152         * File creation time. Its function is same as that of
 153         * struct timespec i_{a,c,m}time in the generic inode.
 154         */
 155        struct timespec i_crtime;
 156};
 157
 158#endif  /* _LINUX_EXT4_FS_I */
 159