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efs_extent.h revision 1.3.2.2 
      1  1.3.2.2  ad /*	$NetBSD: efs_extent.h,v 1.3.2.2 2007/07/15 16:15:22 ad Exp $	*/
      2  1.3.2.2  ad 
      3  1.3.2.2  ad /*
      4  1.3.2.2  ad  * Copyright (c) 2006 Stephen M. Rumble <rumble (at) ephemeral.org>
      5  1.3.2.2  ad  *
      6  1.3.2.2  ad  * Permission to use, copy, modify, and distribute this software for any
      7  1.3.2.2  ad  * purpose with or without fee is hereby granted, provided that the above
      8  1.3.2.2  ad  * copyright notice and this permission notice appear in all copies.
      9  1.3.2.2  ad  *
     10  1.3.2.2  ad  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     11  1.3.2.2  ad  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     12  1.3.2.2  ad  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     13  1.3.2.2  ad  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     14  1.3.2.2  ad  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     15  1.3.2.2  ad  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     16  1.3.2.2  ad  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     17  1.3.2.2  ad  */
     18  1.3.2.2  ad 
     19  1.3.2.2  ad /*
     20  1.3.2.2  ad  * EFS extent descriptor format and sundry.
     21  1.3.2.2  ad  *
     22  1.3.2.2  ad  * See IRIX inode(4)
     23  1.3.2.2  ad  */
     24  1.3.2.2  ad 
     25  1.3.2.2  ad #ifndef _FS_EFS_EFS_EXTENT_H_
     26  1.3.2.2  ad #define _FS_EFS_EFS_EXTENT_H_
     27  1.3.2.2  ad 
     28  1.3.2.2  ad /*
     29  1.3.2.2  ad  * EFS on-disk extent descriptor (8 bytes)
     30  1.3.2.2  ad  *
     31  1.3.2.2  ad  * SGI smushed this structure's members into bit fields, but we have to
     32  1.3.2.2  ad  * be a little more portable. Therefore we use the efs_extent (see below)
     33  1.3.2.2  ad  * type for in-core manipulation and convert immediately to and from disk.
     34  1.3.2.2  ad  */
     35  1.3.2.2  ad struct efs_dextent {
     36  1.3.2.2  ad 	union {
     37  1.3.2.2  ad 		uint64_t ex_magic:8,	/* magic number (always 0) */
     38  1.3.2.2  ad 			 ex_bn:24,	/* bb number in filesystem */
     39  1.3.2.2  ad 			 ex_length:8,	/* length of extent (in bb) */
     40  1.3.2.2  ad 			 ex_offset:24;	/* logical file offset (in bb) */
     41  1.3.2.2  ad 		uint8_t  bytes[8];
     42  1.3.2.2  ad 		uint32_t words[2];
     43  1.3.2.2  ad 	} ex_muddle;
     44  1.3.2.2  ad } __packed;
     45  1.3.2.2  ad #define ex_bytes ex_muddle.bytes
     46  1.3.2.2  ad #define ex_words ex_muddle.words
     47  1.3.2.2  ad 
     48  1.3.2.2  ad /*
     49  1.3.2.2  ad  * In-core, unsquished representation of an extent.
     50  1.3.2.2  ad  */
     51  1.3.2.2  ad struct efs_extent {
     52  1.3.2.2  ad 	uint8_t  ex_magic;
     53  1.3.2.2  ad 	uint32_t ex_bn;			/* NB: only 24 bits on disk */
     54  1.3.2.2  ad 	uint8_t  ex_length;
     55  1.3.2.2  ad 	uint32_t ex_offset;		/* NB: only 24 bits on disk */
     56  1.3.2.2  ad };
     57  1.3.2.2  ad 
     58  1.3.2.2  ad #define EFS_EXTENT_MAGIC	0
     59  1.3.2.2  ad #define EFS_EXTENT_BN_MASK	0x00ffffff
     60  1.3.2.2  ad #define EFS_EXTENT_OFFSET_MASK	0x00ffffff
     61  1.3.2.2  ad 
     62  1.3.2.2  ad #define EFS_EXTENTS_PER_BB	(EFS_BB_SIZE / sizeof(struct efs_dextent))
     63  1.3.2.2  ad 
     64  1.3.2.2  ad #endif /* !_FS_EFS_EFS_EXTENT_H_ */
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