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
  23 struct ext3_reserve_window {
  24         __u32                   _rsv_start;     /* First byte reserved */
  25         __u32                   _rsv_end;       /* Last byte reserved or 0 */
  26 };
  27
  28 struct ext3_reserve_window_node {
  29         struct rb_node          rsv_node;
  30         __u32                   rsv_goal_size;
  31         __u32                   rsv_alloc_hit;
  32         struct ext3_reserve_window      rsv_window;
  33 };
  34
  35 struct ext3_block_alloc_info {
  36         /* information about reservation window */
  37         struct ext3_reserve_window_node rsv_window_node;
  38         /*
  39          * was i_next_alloc_block in ext3_inode_info
  40          * is the logical (file-relative) number of the
  41          * most-recently-allocated block in this file.
  42          * We use this for detecting linearly ascending allocation requests.
  43          */
  44         __u32                   last_alloc_logical_block;
  45         /*
  46          * Was i_next_alloc_goal in ext3_inode_info
  47          * is the *physical* companion to i_next_alloc_block.
  48          * it the the physical block number of the block which was most-recentl
  49          * allocated to this file.  This give us the goal (target) for the next
  50          * allocation when we detect linearly ascending requests.
  51          */
  52         __u32                   last_alloc_physical_block;
  53 };
  54
  55 #define rsv_start rsv_window._rsv_start
  56 #define rsv_end rsv_window._rsv_end
  57
  58 /*
  59  * third extended file system inode data in memory
  60  */
  61 struct ext3_inode_info {
  62         __le32  i_data[15];     /* unconverted */
  63         __u32   i_flags;
  64 #ifdef EXT3_FRAGMENTS
  65         __u32   i_faddr;
  66         __u8    i_frag_no;
  67         __u8    i_frag_size;
  68 #endif
  69         __u32   i_file_acl;
  70         __u32   i_dir_acl;
  71         __u32   i_dtime;
  72
  73         /*
  74          * i_block_group is the number of the block group which contains
  75          * this file's inode.  Constant across the lifetime of the inode,
  76          * it is ued for making block allocation decisions - we try to
  77          * place a file's data blocks near its inode block, and new inodes
  78          * near to their parent directory's inode.
  79          */
  80         __u32   i_block_group;
  81         __u32   i_state;                /* Dynamic state flags for ext3 */
  82
  83         /* block reservation info */
  84         struct ext3_block_alloc_info *i_block_alloc_info;
  85
  86         __u32   i_dir_start_lookup;
  87 #ifdef CONFIG_EXT3_FS_XATTR
  88         /*
  89          * Extended attributes can be read independently of the main file
  90          * data. Taking i_sem even when reading would cause contention
  91          * between readers of EAs and writers of regular file data, so
  92          * instead we synchronize on xattr_sem when reading or changing
  93          * EAs.
  94          */
  95         struct rw_semaphore xattr_sem;
  96 #endif
  97 #ifdef CONFIG_EXT3_FS_POSIX_ACL
  98         struct posix_acl        *i_acl;
  99         struct posix_acl        *i_default_acl;
 100 #endif
 101
 102         struct list_head i_orphan;      /* unlinked but open inodes */
 103
 104         /*
 105          * i_disksize keeps track of what the inode size is ON DISK, not
 106          * in memory.  During truncate, i_size is set to the new size by
 107          * the VFS prior to calling ext3_truncate(), but the filesystem won't
 108          * set i_disksize to 0 until the truncate is actually under way.
 109          *
 110          * The intent is that i_disksize always represents the blocks which
 111          * are used by this file.  This allows recovery to restart truncate
 112          * on orphans if we crash during truncate.  We actually write i_disksize
 113          * into the on-disk inode when writing inodes out, instead of i_size.
 114          *
 115          * The only time when i_disksize and i_size may be different is when
 116          * a truncate is in progress.  The only things which change i_disksize
 117          * are ext3_get_block (growth) and ext3_truncate (shrinkth).
 118          */
 119         loff_t  i_disksize;
 120
 121         /* on-disk additional length */
 122         __u16 i_extra_isize;
 123
 124         /*
 125          * truncate_sem is for serialising ext3_truncate() against
 126          * ext3_getblock().  In the 2.4 ext2 design, great chunks of inode's
 127          * data tree are chopped off during truncate. We can't do that in
 128          * ext3 because whenever we perform intermediate commits during
 129          * truncate, the inode and all the metadata blocks *must* be in a
 130          * consistent state which allows truncation of the orphans to restart
 131          * during recovery.  Hence we must fix the get_block-vs-truncate race
 132          * by other means, so we have truncate_sem.
 133          */
 134         struct semaphore truncate_sem;
 135         struct inode vfs_inode;
 136 };
 137
 138 #endif  /* _LINUX_EXT3_FS_I */