54 lines
1.6 KiB
HTML
54 lines
1.6 KiB
HTML
<!-- X-URL: http://step.polymtl.ca/~ldd/ext2fs/ext2fs_5.html -->
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<!-- This HTML file has been created by texi2html 1.29
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from ext2fs.texi on 3 August 1994 -->
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<TITLE>Analysis of the Ext2fs structure - Group Descriptors</TITLE>
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<P>Go to the <A HREF="ext2fs_4.html">previous</A>, <A HREF="ext2fs_6.html">next</A> section.<P>
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<H1><A NAME="SEC5" HREF="ext2fs_toc.html#SEC5">Group Descriptors</A></H1>
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<P>
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On disk, the group descriptors immediately follow the superblock and
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each descriptor has the following layout:
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<P>
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<PRE>
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struct ext2_group_desc
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{
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unsigned long bg_block_bitmap;
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unsigned long bg_inode_bitmap;
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unsigned long bg_inode_table;
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unsigned short bg_free_blocks_count;
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unsigned short bg_free_inodes_count;
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unsigned short bg_used_dirs_count;
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unsigned short bg_pad;
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unsigned long bg_reserved[3];
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};
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</PRE>
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<P>
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<DL COMPACT>
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<DT><CODE>bg_block_bitmap</CODE>
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<DD>points to the blocks bitmap block for the group.
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<P>
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<DT><CODE>bg_inode_bitmap</CODE>
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<DD>points to the inodes bitmap block for the group.
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<P>
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<DT><CODE>bg_inode_table</CODE>
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<DD>points to the inodes table first block.
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<P>
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<DT><CODE>bg_free_blocks_count</CODE>
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<DD>number of free blocks in the group.
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<P>
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<DT><CODE>bg_free_inodes_count</CODE>
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<DD>number of free inodes in the group.
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<P>
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<DT><CODE>bg_used_dirs_count</CODE>
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<DD>number of inodes allocated to directories in the group.
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<P>
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<DT><CODE>bg_pad</CODE>
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<DD>padding.
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</DL>
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<P>
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The information in a group descriptor pertains only to the group it is
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actually describing.
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<P>
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<P>Go to the <A HREF="ext2fs_4.html">previous</A>, <A HREF="ext2fs_6.html">next</A> section.<P>
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