46 lines
943 B
C
46 lines
943 B
C
//
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// ramdisk that uses the disk image loaded by qemu -rdinit fs.img
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//
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#include "types.h"
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#include "riscv.h"
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#include "defs.h"
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#include "param.h"
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#include "memlayout.h"
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#include "spinlock.h"
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#include "sleeplock.h"
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#include "fs.h"
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#include "buf.h"
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void
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ramdiskinit(void)
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{
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}
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// If B_DIRTY is set, write buf to disk, clear B_DIRTY, set B_VALID.
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// Else if B_VALID is not set, read buf from disk, set B_VALID.
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void
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ramdiskrw(struct buf *b)
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{
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if(!holdingsleep(&b->lock))
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panic("ramdiskrw: buf not locked");
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if((b->flags & (B_VALID|B_DIRTY)) == B_VALID)
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panic("ramdiskrw: nothing to do");
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if(b->blockno >= FSSIZE)
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panic("ramdiskrw: blockno too big");
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uint64 diskaddr = b->blockno * BSIZE;
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char *addr = (char *)RAMDISK + diskaddr;
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if(b->flags & B_DIRTY){
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// write
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memmove(addr, b->data, BSIZE);
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b->flags &= ~B_DIRTY;
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} else {
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// read
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memmove(b->data, addr, BSIZE);
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b->flags |= B_VALID;
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}
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}
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