fs/xfs/linux-2.6/xfs_export.h

   1 /*
   2  * Copyright (c) 2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #ifndef __XFS_EXPORT_H__
  19 #define __XFS_EXPORT_H__
  20
  21 /*
  22  * Common defines for code related to exporting XFS filesystems over NFS.
  23  *
  24  * The NFS fileid goes out on the wire as an array of
  25  * 32bit unsigned ints in host order.  There are 5 possible
  26  * formats.
  27  *
  28  * (1)  fileid_type=0x00
  29  *      (no fileid data; handled by the generic code)
  30  *
  31  * (2)  fileid_type=0x01
  32  *      inode-num
  33  *      generation
  34  *
  35  * (3)  fileid_type=0x02
  36  *      inode-num
  37  *      generation
  38  *      parent-inode-num
  39  *      parent-generation
  40  *
  41  * (4)  fileid_type=0x81
  42  *      inode-num-lo32
  43  *      inode-num-hi32
  44  *      generation
  45  *
  46  * (5)  fileid_type=0x82
  47  *      inode-num-lo32
  48  *      inode-num-hi32
  49  *      generation
  50  *      parent-inode-num-lo32
  51  *      parent-inode-num-hi32
  52  *      parent-generation
  53  *
  54  * Note, the NFS filehandle also includes an fsid portion which
  55  * may have an inode number in it.  That number is hardcoded to
  56  * 32bits and there is no way for XFS to intercept it.  In
  57  * practice this means when exporting an XFS filesystem with 64bit
  58  * inodes you should either export the mountpoint (rather than
  59  * a subdirectory) or use the "fsid" export option.
  60  */
  61
  62 /* This flag goes on the wire.  Don't play with it. */
  63 #define XFS_FILEID_TYPE_64FLAG  0x80    /* NFS fileid has 64bit inodes */
  64
  65 /* Calculate the length in u32 units of the fileid data */
  66 static inline int
  67 xfs_fileid_length(int hasparent, int is64)
  68 {
  69         return hasparent ? (is64 ? 6 : 4) : (is64 ? 3 : 2);
  70 }
  71
  72 /*
  73  * Decode encoded inode information (either for the inode itself
  74  * or the parent) into an xfs_fid2_t structure.  Advances and
  75  * returns the new data pointer
  76  */
  77 static inline __u32 *
  78 xfs_fileid_decode_fid2(__u32 *p, xfs_fid2_t *fid, int is64)
  79 {
  80         fid->fid_len = sizeof(xfs_fid2_t) - sizeof(fid->fid_len);
  81         fid->fid_pad = 0;
  82         fid->fid_ino = *p++;
  83 #if XFS_BIG_INUMS
  84         if (is64)
  85                 fid->fid_ino |= (((__u64)(*p++)) << 32);
  86 #endif
  87         fid->fid_gen = *p++;
  88         return p;
  89 }
  90
  91 /*
  92  * Encode inode information (either for the inode itself or the
  93  * parent) into a fileid buffer.  Advances and returns the new
  94  * data pointer.
  95  */
  96 static inline __u32 *
  97 xfs_fileid_encode_inode(__u32 *p, struct inode *inode, int is64)
  98 {
  99         *p++ = (__u32)inode->i_ino;
 100 #if XFS_BIG_INUMS
 101         if (is64)
 102                 *p++ = (__u32)(inode->i_ino >> 32);
 103 #endif
 104         *p++ = inode->i_generation;
 105         return p;
 106 }
 107
 108 #endif  /* __XFS_EXPORT_H__ */