include/linux/ext3_fs_i.h

   1 /*
   2  *  linux/include/linux/ext3_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_EXT3_FS_I
  17 #define _LINUX_EXT3_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 */
  25 typedef int ext3_grpblk_t;
  26
  27 /* data type for filesystem-wide blocks number */
  28 typedef unsigned long ext3_fsblk_t;
  29
  30 #define E3FSBLK "%lu"
  31
  32 struct ext3_reserve_window {
  33         ext3_fsblk_t    _rsv_start;     /* First byte reserved */
  34         ext3_fsblk_t    _rsv_end;       /* Last byte reserved or 0 */
  35 };
  36
  37 struct ext3_reserve_window_node {
  38         struct rb_node          rsv_node;
  39         __u32                   rsv_goal_size;
  40         __u32                   rsv_alloc_hit;
  41         struct ext3_reserve_window      rsv_window;
  42 };
  43
  44 struct ext3_block_alloc_info {
  45         /* information about reservation window */
  46         struct ext3_reserve_window_node rsv_window_node;
  47         /*
  48          * was i_next_alloc_block in ext3_inode_info
  49          * is the logical (file-relative) number of the
  50          * most-recently-allocated block in this file.
  51          * We use this for detecting linearly ascending allocation requests.
  52          */
  53         __u32                   last_alloc_logical_block;
  54         /*
  55          * Was i_next_alloc_goal in ext3_inode_info
  56          * is the *physical* companion to i_next_alloc_block.
  57          * it the physical block number of the block which was most-recentl
  58          * allocated to this file.  This give us the goal (target) for the next
  59          * allocation when we detect linearly ascending requests.
  60          */
  61         ext3_fsblk_t            last_alloc_physical_block;
  62 };
  63
  64 #define rsv_start rsv_window._rsv_start
  65 #define rsv_end rsv_window._rsv_end
  66
  67 /*
  68  * third extended file system inode data in memory
  69  */
  70 struct ext3_inode_info {
  71         __le32  i_data[15];     /* unconverted */
  72         __u32   i_flags;
  73 #ifdef EXT3_FRAGMENTS
  74         __u32   i_faddr;
  75         __u8    i_frag_no;
  76         __u8    i_frag_size;
  77 #endif
  78         ext3_fsblk_t    i_file_acl;
  79         __u32   i_dir_acl;
  80         __u32   i_dtime;
  81
  82         /*
  83          * i_block_group is the number of the block group which contains
  84          * this file's inode.  Constant across the lifetime of the inode,
  85          * it is ued for making block allocation decisions - we try to
  86          * place a file's data blocks near its inode block, and new inodes
  87          * near to their parent directory's inode.
  88          */
  89         __u32   i_block_group;
  90         __u32   i_state;                /* Dynamic state flags for ext3 */
  91
  92         /* block reservation info */
  93         struct ext3_block_alloc_info *i_block_alloc_info;
  94
  95         __u32   i_dir_start_lookup;
  96 #ifdef CONFIG_EXT3_FS_XATTR
  97         /*
  98          * Extended attributes can be read independently of the main file
  99          * data. Taking i_mutex even when reading would cause contention
 100          * between readers of EAs and writers of regular file data, so
 101          * instead we synchronize on xattr_sem when reading or changing
 102          * EAs.
 103          */
 104         struct rw_semaphore xattr_sem;
 105 #endif
 106
 107         struct list_head i_orphan;      /* unlinked but open inodes */
 108
 109         /*
 110          * i_disksize keeps track of what the inode size is ON DISK, not
 111          * in memory.  During truncate, i_size is set to the new size by
 112          * the VFS prior to calling ext3_truncate(), but the filesystem won't
 113          * set i_disksize to 0 until the truncate is actually under way.
 114          *
 115          * The intent is that i_disksize always represents the blocks which
 116          * are used by this file.  This allows recovery to restart truncate
 117          * on orphans if we crash during truncate.  We actually write i_disksize
 118          * into the on-disk inode when writing inodes out, instead of i_size.
 119          *
 120          * The only time when i_disksize and i_size may be different is when
 121          * a truncate is in progress.  The only things which change i_disksize
 122          * are ext3_get_block (growth) and ext3_truncate (shrinkth).
 123          */
 124         loff_t  i_disksize;
 125
 126         /* on-disk additional length */
 127         __u16 i_extra_isize;
 128
 129         /*
 130          * truncate_mutex is for serialising ext3_truncate() against
 131          * ext3_getblock().  In the 2.4 ext2 design, great chunks of inode's
 132          * data tree are chopped off during truncate. We can't do that in
 133          * ext3 because whenever we perform intermediate commits during
 134          * truncate, the inode and all the metadata blocks *must* be in a
 135          * consistent state which allows truncation of the orphans to restart
 136          * during recovery.  Hence we must fix the get_block-vs-truncate race
 137          * by other means, so we have truncate_mutex.
 138          */
 139         struct mutex truncate_mutex;
 140         struct inode vfs_inode;
 141 };
 142
 143 #endif  /* _LINUX_EXT3_FS_I */