Re: disklabel support

[tripun goel]

On Thu, Apr 12, 2012 at 8:17 PM, Vladimir 'φ-coder/phcoder' Serbinenko
<address@hidden> wrote:
> On 12.04.2012 16:43, tripun goel wrote:
>> Please see if this helps ?
>> http://leaf.dragonflybsd.org/cgi/web-man?command=disklabel64&section=8
> It doesn't. You need on-disk format.
>
72/*
73 * A disklabel64 starts at slice relative offset 0, NOT SECTOR 1.  In
74 * otherwords, d_magic is at byte offset 512 within the slice, regardless
75 * of the sector size.
76 *
77 * The d_reserved0 area is not included in the crc and any kernel writeback
78 * of the label will not change the d_reserved area on-disk.  It is purely
79 * a shim to allow us to avoid sector calculations when reading or
80 * writing the label.  Since byte offsets are used in our 64 bit disklabel,
81 * the entire disklabel and the I/O required to access it becomes
82 * sector-agnostic.
83 */
84struct disklabel64 {
85      char      d_reserved0[512];     /* reserved or unused */
86      u_int32_t d_magic;              /* the magic number */
87      u_int32_t d_crc;                /* crc32() d_magic thru last part */
88      u_int32_t d_align;              /* partition alignment requirement */
89      u_int32_t d_npartitions;        /* number of partitions */
90      struct uuid d_stor_uuid;        /* unique uuid for label */
91
92      u_int64_t d_total_size;         /* total size incl everything (bytes) */
93      u_int64_t d_bbase;              /* boot area base offset (bytes) */
94                                      /* boot area is pbase - bbase */
95      u_int64_t d_pbase;              /* first allocatable offset (bytes) */
96      u_int64_t d_pstop;              /* last allocatable offset+1 (bytes) */
97      u_int64_t d_abase;              /* location of backup copy if not 0 */
98
99      u_char    d_packname[64];
100     u_char    d_reserved[64];
101
102     /*
103      * Note: offsets are relative to the base of the slice, NOT to
104      * d_pbase.  Unlike 32 bit disklabels the on-disk format for
105      * a 64 bit disklabel remains slice-relative.
106      *
107      * An uninitialized partition has a p_boffset and p_bsize of 0.
108      *
109      * If p_fstype is not supported for a live partition it is set
110      * to FS_OTHER.  This is typically the case when the filesystem
111      * is identified by its uuid.
112      */
113     struct partition64 {            /* the partition table */
114             u_int64_t p_boffset;    /* slice relative offset, in bytes */
115             u_int64_t p_bsize;      /* size of partition, in bytes */
116             u_int8_t  p_fstype;
117             u_int8_t  p_unused01;   /* reserved, must be 0 */
118             u_int8_t  p_unused02;   /* reserved, must be 0 */
119             u_int8_t  p_unused03;   /* reserved, must be 0 */
120             u_int32_t p_unused04;   /* reserved, must be 0 */
121             u_int32_t p_unused05;   /* reserved, must be 0 */
122             u_int32_t p_unused06;   /* reserved, must be 0 */
123             struct uuid p_type_uuid;/* mount type as UUID */
124             struct uuid p_stor_uuid;/* unique uuid for storage */
125     } d_partitions[MAXPARTITIONS64];/* actually may be more */
126};


> --
> Regards
> Vladimir 'φ-coder/phcoder' Serbinenko
>
>
>
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