85 lines
1.6 KiB
C
85 lines
1.6 KiB
C
#include "stpdfs.h"
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <unistd.h>
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#include <time.h>
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size_t
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stpdfs_write(int fd, uint32_t blocknum, void *data, size_t size)
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{
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uint8_t buffer[STPDFS_BLOCK_SIZE];
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if (size > STPDFS_BLOCK_SIZE) return (-1);
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lseek(fd, blocknum * STPDFS_BLOCK_SIZE, SEEK_SET);
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if (size > 0)
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{
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memcpy(buffer, data, size);
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return (write(fd, buffer, STPDFS_BLOCK_SIZE));
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}
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return (write(fd, data, size));
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}
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size_t
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stpdfs_read(int fd, uint32_t blocknum, void *data, size_t size)
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{
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lseek(fd, blocknum * STPDFS_BLOCK_SIZE, SEEK_SET);
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return (read(fd, data, size));
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}
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uint32_t
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stpdfs_alloc_block(int fd, struct stpdfs_sb *sb)
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{
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uint32_t blocknum;
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struct stpdfs_free freelist;
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sb->state = STPDFS_DIRTY; /* mark state dirty */
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redo:
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sb->nfree--;
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blocknum = sb->free[sb->nfree];
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if (sb->nfree == 0 && blocknum != 0)
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{
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stpdfs_read(fd, blocknum, &freelist, sizeof(struct stpdfs_free));
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memcpy(sb->free, &freelist, sizeof(uint32_t) * 100);
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sb->nfree = freelist.nfree;
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goto redo;
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}
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sb->time = time(NULL);
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return (blocknum);
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}
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int
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stpdfs_free_block(int fd, struct stpdfs_sb *sb, uint32_t blocknum)
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{
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struct stpdfs_free copy;
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if (blocknum == 0 || blocknum >= sb->fsize)
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{
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return (-1);
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}
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sb->state = STPDFS_DIRTY; /* mark state dirty */
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if (sb->nfree == 100)
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{
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memcpy(©, sb->free, sizeof(uint32_t) * 100);
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copy.nfree = sb->nfree;
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stpdfs_write(fd, blocknum, ©, sizeof(struct stpdfs_free));
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sb->nfree = 1;
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sb->free[0] = blocknum;
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}
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else
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{
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sb->free[sb->nfree++] = blocknum;
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}
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sb->time = time(NULL);
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return (0);
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} |