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 /* data type for file logical block number */
  31 typedef __u32 ext4_lblk_t;
  32
  33 /* data type for block group number */
  34 typedef unsigned long ext4_group_t;
  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         ext4_lblk_t 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 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         ext4_fsblk_t    ec_start;
  76         ext4_lblk_t     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         ext4_fsblk_t    i_file_acl;
  88         __u32   i_dir_acl;
  89         __u32   i_dtime;
  90
  91         /*
  92          * i_block_group is the number of the block group which contains
  93          * this file's inode.  Constant across the lifetime of the inode,
  94          * it is ued for making block allocation decisions - we try to
  95          * place a file's data blocks near its inode block, and new inodes
  96          * near to their parent directory's inode.
  97          */
  98         ext4_group_t    i_block_group;
  99         __u32   i_state;                /* Dynamic state flags for ext4 */
 100
 101         /* block reservation info */
 102         struct ext4_block_alloc_info *i_block_alloc_info;
 103
 104         ext4_lblk_t             i_dir_start_lookup;
 105 #ifdef CONFIG_EXT4DEV_FS_XATTR
 106         /*
 107          * Extended attributes can be read independently of the main file
 108          * data. Taking i_mutex even when reading would cause contention
 109          * between readers of EAs and writers of regular file data, so
 110          * instead we synchronize on xattr_sem when reading or changing
 111          * EAs.
 112          */
 113         struct rw_semaphore xattr_sem;
 114 #endif
 115 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
 116         struct posix_acl        *i_acl;
 117         struct posix_acl        *i_default_acl;
 118 #endif
 119
 120         struct list_head i_orphan;      /* unlinked but open inodes */
 121
 122         /*
 123          * i_disksize keeps track of what the inode size is ON DISK, not
 124          * in memory.  During truncate, i_size is set to the new size by
 125          * the VFS prior to calling ext4_truncate(), but the filesystem won't
 126          * set i_disksize to 0 until the truncate is actually under way.
 127          *
 128          * The intent is that i_disksize always represents the blocks which
 129          * are used by this file.  This allows recovery to restart truncate
 130          * on orphans if we crash during truncate.  We actually write i_disksize
 131          * into the on-disk inode when writing inodes out, instead of i_size.
 132          *
 133          * The only time when i_disksize and i_size may be different is when
 134          * a truncate is in progress.  The only things which change i_disksize
 135          * are ext4_get_block (growth) and ext4_truncate (shrinkth).
 136          */
 137         loff_t  i_disksize;
 138
 139         /* on-disk additional length */
 140         __u16 i_extra_isize;
 141
 142         /*
 143          * truncate_mutex is for serialising ext4_truncate() against
 144          * ext4_getblock().  In the 2.4 ext2 design, great chunks of inode's
 145          * data tree are chopped off during truncate. We can't do that in
 146          * ext4 because whenever we perform intermediate commits during
 147          * truncate, the inode and all the metadata blocks *must* be in a
 148          * consistent state which allows truncation of the orphans to restart
 149          * during recovery.  Hence we must fix the get_block-vs-truncate race
 150          * by other means, so we have truncate_mutex.
 151          */
 152         struct mutex truncate_mutex;
 153         struct inode vfs_inode;
 154
 155         unsigned long i_ext_generation;
 156         struct ext4_ext_cache i_cached_extent;
 157         /*
 158          * File creation time. Its function is same as that of
 159          * struct timespec i_{a,c,m}time in the generic inode.
 160          */
 161         struct timespec i_crtime;
 162 };
 163
 164 #endif  /* _LINUX_EXT4_FS_I */