Sanchayan Maity
b28eba04a8
Use 10 direct block numbers, 2 indirect block numbers and one double indirect block number to increase the maximum file size to around 8MB. Using this scheme, we can address a total of blocks 10 + 2 * 128 + 128 * 128 = 16650 blocks or just over 8MB.
39 lines
767 B
C
39 lines
767 B
C
struct file {
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enum { FD_NONE, FD_PIPE, FD_INODE } type;
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int ref; // reference count
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char readable;
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char writable;
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struct pipe *pipe;
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struct inode *ip;
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uint off;
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};
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// in-memory copy of an inode
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struct inode {
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uint dev; // Device number
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uint inum; // Inode number
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int ref; // Reference count
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int flags; // I_BUSY, I_VALID
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short type; // copy of disk inode
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short major;
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short minor;
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short nlink;
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uint size;
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uint addrs[NDIRECT+3];
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};
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#define I_BUSY 0x1
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#define I_VALID 0x2
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// table mapping major device number to
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// device functions
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struct devsw {
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int (*read)(struct inode*, char*, int);
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int (*write)(struct inode*, char*, int);
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};
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extern struct devsw devsw[];
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#define CONSOLE 1
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