include/linux/ext4_fs_i.h

   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 */
  25 typedef int ext4_grpblk_t;
  26
  27 /* data type for filesystem-wide blocks number */
  28 typedef unsigned long long ext4_fsblk_t;
  29
  30 struct 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
  35 struct 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
  42 struct 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 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  */
  68 struct 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  */
  78 struct ext4_inode_info {
  79         __le32  i_data[15];     /* unconverted */
  80         __u32   i_flags;
  81 #ifdef EXT4_FRAGMENTS
  82         __u32   i_faddr;
  83         __u8    i_frag_no;
  84         __u8    i_frag_size;
  85 #endif
  86         ext4_fsblk_t    i_file_acl;
  87         __u32   i_dir_acl;
  88         __u32   i_dtime;
  89
  90         /*
  91          * i_block_group is the number of the block group which contains
  92          * this file's inode.  Constant across the lifetime of the inode,
  93          * it is ued for making block allocation decisions - we try to
  94          * place a file's data blocks near its inode block, and new inodes
  95          * near to their parent directory's inode.
  96          */
  97         __u32   i_block_group;
  98         __u32   i_state;                /* Dynamic state flags for ext4 */
  99
 100         /* block reservation info */
 101         struct ext4_block_alloc_info *i_block_alloc_info;
 102
 103         __u32   i_dir_start_lookup;
 104 #ifdef CONFIG_EXT4DEV_FS_XATTR
 105         /*
 106          * Extended attributes can be read independently of the main file
 107          * data. Taking i_mutex even when reading would cause contention
 108          * between readers of EAs and writers of regular file data, so
 109          * instead we synchronize on xattr_sem when reading or changing
 110          * EAs.
 111          */
 112         struct rw_semaphore xattr_sem;
 113 #endif
 114 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
 115         struct posix_acl        *i_acl;
 116         struct posix_acl        *i_default_acl;
 117 #endif
 118
 119         struct list_head i_orphan;      /* unlinked but open inodes */
 120
 121         /*
 122          * i_disksize keeps track of what the inode size is ON DISK, not
 123          * in memory.  During truncate, i_size is set to the new size by
 124          * the VFS prior to calling ext4_truncate(), but the filesystem won't
 125          * set i_disksize to 0 until the truncate is actually under way.
 126          *
 127          * The intent is that i_disksize always represents the blocks which
 128          * are used by this file.  This allows recovery to restart truncate
 129          * on orphans if we crash during truncate.  We actually write i_disksize
 130          * into the on-disk inode when writing inodes out, instead of i_size.
 131          *
 132          * The only time when i_disksize and i_size may be different is when
 133          * a truncate is in progress.  The only things which change i_disksize
 134          * are ext4_get_block (growth) and ext4_truncate (shrinkth).
 135          */
 136         loff_t  i_disksize;
 137
 138         /* on-disk additional length */
 139         __u16 i_extra_isize;
 140
 141         /*
 142          * truncate_mutex is for serialising ext4_truncate() against
 143          * ext4_getblock().  In the 2.4 ext2 design, great chunks of inode's
 144          * data tree are chopped off during truncate. We can't do that in
 145          * ext4 because whenever we perform intermediate commits during
 146          * truncate, the inode and all the metadata blocks *must* be in a
 147          * consistent state which allows truncation of the orphans to restart
 148          * during recovery.  Hence we must fix the get_block-vs-truncate race
 149          * by other means, so we have truncate_mutex.
 150          */
 151         struct mutex truncate_mutex;
 152         struct inode vfs_inode;
 153
 154         unsigned long i_ext_generation;
 155         struct ext4_ext_cache i_cached_extent;
 156 };
 157
 158 #endif  /* _LINUX_EXT4_FS_I */