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
  21 /*
  22  * second extended file system inode data in memory
  23  */
  24 struct ext3_inode_info {
  25         __le32  i_data[15];     /* unconverted */
  26         __u32   i_flags;
  27 #ifdef EXT3_FRAGMENTS
  28         __u32   i_faddr;
  29         __u8    i_frag_no;
  30         __u8    i_frag_size;
  31 #endif
  32         __u32   i_file_acl;
  33         __u32   i_dir_acl;
  34         __u32   i_dtime;
  35
  36         /*
  37          * i_block_group is the number of the block group which contains
  38          * this file's inode.  Constant across the lifetime of the inode,
  39          * it is ued for making block allocation decisions - we try to
  40          * place a file's data blocks near its inode block, and new inodes
  41          * near to their parent directory's inode.
  42          */
  43         __u32   i_block_group;
  44         __u32   i_state;                /* Dynamic state flags for ext3 */
  45
  46         /*
  47          * i_next_alloc_block is the logical (file-relative) number of the
  48          * most-recently-allocated block in this file.  Yes, it is misnamed.
  49          * We use this for detecting linearly ascending allocation requests.
  50          */
  51         __u32   i_next_alloc_block;
  52
  53         /*
  54          * i_next_alloc_goal is the *physical* companion to i_next_alloc_block.
  55          * it the the physical block number of the block which was most-recently
  56          * allocated to this file.  This give us the goal (target) for the next
  57          * allocation when we detect linearly ascending requests.
  58          */
  59         __u32   i_next_alloc_goal;
  60 #ifdef EXT3_PREALLOCATE
  61         __u32   i_prealloc_block;
  62         __u32   i_prealloc_count;
  63 #endif
  64         __u32   i_dir_start_lookup;
  65 #ifdef CONFIG_EXT3_FS_XATTR
  66         /*
  67          * Extended attributes can be read independently of the main file
  68          * data. Taking i_sem even when reading would cause contention
  69          * between readers of EAs and writers of regular file data, so
  70          * instead we synchronize on xattr_sem when reading or changing
  71          * EAs.
  72          */
  73         struct rw_semaphore xattr_sem;
  74 #endif
  75 #ifdef CONFIG_EXT3_FS_POSIX_ACL
  76         struct posix_acl        *i_acl;
  77         struct posix_acl        *i_default_acl;
  78 #endif
  79
  80         struct list_head i_orphan;      /* unlinked but open inodes */
  81
  82         /*
  83          * i_disksize keeps track of what the inode size is ON DISK, not
  84          * in memory.  During truncate, i_size is set to the new size by
  85          * the VFS prior to calling ext3_truncate(), but the filesystem won't
  86          * set i_disksize to 0 until the truncate is actually under way.
  87          *
  88          * The intent is that i_disksize always represents the blocks which
  89          * are used by this file.  This allows recovery to restart truncate
  90          * on orphans if we crash during truncate.  We actually write i_disksize
  91          * into the on-disk inode when writing inodes out, instead of i_size.
  92          *
  93          * The only time when i_disksize and i_size may be different is when
  94          * a truncate is in progress.  The only things which change i_disksize
  95          * are ext3_get_block (growth) and ext3_truncate (shrinkth).
  96          */
  97         loff_t  i_disksize;
  98
  99         /*
 100          * truncate_sem is for serialising ext3_truncate() against
 101          * ext3_getblock().  In the 2.4 ext2 design, great chunks of inode's
 102          * data tree are chopped off during truncate. We can't do that in
 103          * ext3 because whenever we perform intermediate commits during
 104          * truncate, the inode and all the metadata blocks *must* be in a
 105          * consistent state which allows truncation of the orphans to restart
 106          * during recovery.  Hence we must fix the get_block-vs-truncate race
 107          * by other means, so we have truncate_sem.
 108          */
 109         struct semaphore truncate_sem;
 110         struct inode vfs_inode;
 111 };
 112
 113 #endif  /* _LINUX_EXT3_FS_I */