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 sector_t ext4_fsblk_t;
  29
  30 #if BITS_PER_LONG == 64
  31 #define E3FSBLK "%lu"
  32 #else
  33 #define E3FSBLK "%llu"
  34 #endif
  35
  36 struct ext4_reserve_window {
  37         ext4_fsblk_t    _rsv_start;     /* First byte reserved */
  38         ext4_fsblk_t    _rsv_end;       /* Last byte reserved or 0 */
  39 };
  40
  41 struct ext4_reserve_window_node {
  42         struct rb_node          rsv_node;
  43         __u32                   rsv_goal_size;
  44         __u32                   rsv_alloc_hit;
  45         struct ext4_reserve_window      rsv_window;
  46 };
  47
  48 struct ext4_block_alloc_info {
  49         /* information about reservation window */
  50         struct ext4_reserve_window_node rsv_window_node;
  51         /*
  52          * was i_next_alloc_block in ext4_inode_info
  53          * is the logical (file-relative) number of the
  54          * most-recently-allocated block in this file.
  55          * We use this for detecting linearly ascending allocation requests.
  56          */
  57         __u32                   last_alloc_logical_block;
  58         /*
  59          * Was i_next_alloc_goal in ext4_inode_info
  60          * is the *physical* companion to i_next_alloc_block.
  61          * it the the physical block number of the block which was most-recentl
  62          * allocated to this file.  This give us the goal (target) for the next
  63          * allocation when we detect linearly ascending requests.
  64          */
  65         ext4_fsblk_t            last_alloc_physical_block;
  66 };
  67
  68 #define rsv_start rsv_window._rsv_start
  69 #define rsv_end rsv_window._rsv_end
  70
  71 /*
  72  * storage for cached extent
  73  */
  74 struct ext4_ext_cache {
  75         __u32   ec_start;
  76         __u32   ec_block;
  77         __u32   ec_len; /* must be 32bit to return holes */
  78         __u32   ec_type;
  79 };
  80
  81 /*
  82  * third extended file system inode data in memory
  83  */
  84 struct ext4_inode_info {
  85         __le32  i_data[15];     /* unconverted */
  86         __u32   i_flags;
  87 #ifdef EXT4_FRAGMENTS
  88         __u32   i_faddr;
  89         __u8    i_frag_no;
  90         __u8    i_frag_size;
  91 #endif
  92         ext4_fsblk_t    i_file_acl;
  93         __u32   i_dir_acl;
  94         __u32   i_dtime;
  95
  96         /*
  97          * i_block_group is the number of the block group which contains
  98          * this file's inode.  Constant across the lifetime of the inode,
  99          * it is ued for making block allocation decisions - we try to
 100          * place a file's data blocks near its inode block, and new inodes
 101          * near to their parent directory's inode.
 102          */
 103         __u32   i_block_group;
 104         __u32   i_state;                /* Dynamic state flags for ext4 */
 105
 106         /* block reservation info */
 107         struct ext4_block_alloc_info *i_block_alloc_info;
 108
 109         __u32   i_dir_start_lookup;
 110 #ifdef CONFIG_EXT4DEV_FS_XATTR
 111         /*
 112          * Extended attributes can be read independently of the main file
 113          * data. Taking i_mutex even when reading would cause contention
 114          * between readers of EAs and writers of regular file data, so
 115          * instead we synchronize on xattr_sem when reading or changing
 116          * EAs.
 117          */
 118         struct rw_semaphore xattr_sem;
 119 #endif
 120 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
 121         struct posix_acl        *i_acl;
 122         struct posix_acl        *i_default_acl;
 123 #endif
 124
 125         struct list_head i_orphan;      /* unlinked but open inodes */
 126
 127         /*
 128          * i_disksize keeps track of what the inode size is ON DISK, not
 129          * in memory.  During truncate, i_size is set to the new size by
 130          * the VFS prior to calling ext4_truncate(), but the filesystem won't
 131          * set i_disksize to 0 until the truncate is actually under way.
 132          *
 133          * The intent is that i_disksize always represents the blocks which
 134          * are used by this file.  This allows recovery to restart truncate
 135          * on orphans if we crash during truncate.  We actually write i_disksize
 136          * into the on-disk inode when writing inodes out, instead of i_size.
 137          *
 138          * The only time when i_disksize and i_size may be different is when
 139          * a truncate is in progress.  The only things which change i_disksize
 140          * are ext4_get_block (growth) and ext4_truncate (shrinkth).
 141          */
 142         loff_t  i_disksize;
 143
 144         /* on-disk additional length */
 145         __u16 i_extra_isize;
 146
 147         /*
 148          * truncate_mutex is for serialising ext4_truncate() against
 149          * ext4_getblock().  In the 2.4 ext2 design, great chunks of inode's
 150          * data tree are chopped off during truncate. We can't do that in
 151          * ext4 because whenever we perform intermediate commits during
 152          * truncate, the inode and all the metadata blocks *must* be in a
 153          * consistent state which allows truncation of the orphans to restart
 154          * during recovery.  Hence we must fix the get_block-vs-truncate race
 155          * by other means, so we have truncate_mutex.
 156          */
 157         struct mutex truncate_mutex;
 158         struct inode vfs_inode;
 159
 160         unsigned long i_ext_generation;
 161         struct ext4_ext_cache i_cached_extent;
 162 };
 163
 164 #endif  /* _LINUX_EXT4_FS_I */