《操作系统》的实验代码。
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#include <defs.h>
#include <string.h>
#include <dev.h>
#include <sfs.h>
#include <iobuf.h>
#include <bitmap.h>
#include <assert.h>
//Basic block-level I/O routines
/* sfs_rwblock_nolock - Basic block-level I/O routine for Rd/Wr one disk block,
* without lock protect for mutex process on Rd/Wr disk block
* @sfs: sfs_fs which will be process
* @buf: the buffer uesed for Rd/Wr
* @blkno: the NO. of disk block
* @write: BOOL: Read or Write
* @check: BOOL: if check (blono < sfs super.blocks)
*/
static int
sfs_rwblock_nolock(struct sfs_fs *sfs, void *buf, uint32_t blkno, bool write, bool check) {
assert((blkno != 0 || !check) && blkno < sfs->super.blocks);
struct iobuf __iob, *iob = iobuf_init(&__iob, buf, SFS_BLKSIZE, blkno * SFS_BLKSIZE);
return dop_io(sfs->dev, iob, write);
}
/* sfs_rwblock - Basic block-level I/O routine for Rd/Wr N disk blocks ,
* with lock protect for mutex process on Rd/Wr disk block
* @sfs: sfs_fs which will be process
* @buf: the buffer uesed for Rd/Wr
* @blkno: the NO. of disk block
* @nblks: Rd/Wr number of disk block
* @write: BOOL: Read - 0 or Write - 1
*/
static int
sfs_rwblock(struct sfs_fs *sfs, void *buf, uint32_t blkno, uint32_t nblks, bool write) {
int ret = 0;
lock_sfs_io(sfs);
{
while (nblks != 0) {
if ((ret = sfs_rwblock_nolock(sfs, buf, blkno, write, 1)) != 0) {
break;
}
blkno ++, nblks --;
buf += SFS_BLKSIZE;
}
}
unlock_sfs_io(sfs);
return ret;
}
/* sfs_rblock - The Wrap of sfs_rwblock function for Rd N disk blocks ,
*
* @sfs: sfs_fs which will be process
* @buf: the buffer uesed for Rd/Wr
* @blkno: the NO. of disk block
* @nblks: Rd/Wr number of disk block
*/
int
sfs_rblock(struct sfs_fs *sfs, void *buf, uint32_t blkno, uint32_t nblks) {
return sfs_rwblock(sfs, buf, blkno, nblks, 0);
}
/* sfs_wblock - The Wrap of sfs_rwblock function for Wr N disk blocks ,
*
* @sfs: sfs_fs which will be process
* @buf: the buffer uesed for Rd/Wr
* @blkno: the NO. of disk block
* @nblks: Rd/Wr number of disk block
*/
int
sfs_wblock(struct sfs_fs *sfs, void *buf, uint32_t blkno, uint32_t nblks) {
return sfs_rwblock(sfs, buf, blkno, nblks, 1);
}
/* sfs_rbuf - The Basic block-level I/O routine for Rd( non-block & non-aligned io) one disk block(using sfs->sfs_buffer)
* with lock protect for mutex process on Rd/Wr disk block
* @sfs: sfs_fs which will be process
* @buf: the buffer uesed for Rd
* @len: the length need to Rd
* @blkno: the NO. of disk block
* @offset: the offset in the content of disk block
*/
int
sfs_rbuf(struct sfs_fs *sfs, void *buf, size_t len, uint32_t blkno, off_t offset) {
assert(offset >= 0 && offset < SFS_BLKSIZE && offset + len <= SFS_BLKSIZE);
int ret;
lock_sfs_io(sfs);
{
if ((ret = sfs_rwblock_nolock(sfs, sfs->sfs_buffer, blkno, 0, 1)) == 0) {
memcpy(buf, sfs->sfs_buffer + offset, len);
}
}
unlock_sfs_io(sfs);
return ret;
}
/* sfs_wbuf - The Basic block-level I/O routine for Wr( non-block & non-aligned io) one disk block(using sfs->sfs_buffer)
* with lock protect for mutex process on Rd/Wr disk block
* @sfs: sfs_fs which will be process
* @buf: the buffer uesed for Wr
* @len: the length need to Wr
* @blkno: the NO. of disk block
* @offset: the offset in the content of disk block
*/
int
sfs_wbuf(struct sfs_fs *sfs, void *buf, size_t len, uint32_t blkno, off_t offset) {
assert(offset >= 0 && offset < SFS_BLKSIZE && offset + len <= SFS_BLKSIZE);
int ret;
lock_sfs_io(sfs);
{
if ((ret = sfs_rwblock_nolock(sfs, sfs->sfs_buffer, blkno, 0, 1)) == 0) {
memcpy(sfs->sfs_buffer + offset, buf, len);
ret = sfs_rwblock_nolock(sfs, sfs->sfs_buffer, blkno, 1, 1);
}
}
unlock_sfs_io(sfs);
return ret;
}
/*
* sfs_sync_super - write sfs->super (in memory) into disk (SFS_BLKN_SUPER, 1) with lock protect.
*/
int
sfs_sync_super(struct sfs_fs *sfs) {
int ret;
lock_sfs_io(sfs);
{
memset(sfs->sfs_buffer, 0, SFS_BLKSIZE);
memcpy(sfs->sfs_buffer, &(sfs->super), sizeof(sfs->super));
ret = sfs_rwblock_nolock(sfs, sfs->sfs_buffer, SFS_BLKN_SUPER, 1, 0);
}
unlock_sfs_io(sfs);
return ret;
}
/*
* sfs_sync_freemap - write sfs bitmap into disk (SFS_BLKN_FREEMAP, nblks) without lock protect.
*/
int
sfs_sync_freemap(struct sfs_fs *sfs) {
uint32_t nblks = sfs_freemap_blocks(&(sfs->super));
return sfs_wblock(sfs, bitmap_getdata(sfs->freemap, NULL), SFS_BLKN_FREEMAP, nblks);
}
/*
* sfs_clear_block - write zero info into disk (blkno, nblks) with lock protect.
* @sfs: sfs_fs which will be process
* @blkno: the NO. of disk block
* @nblks: Rd/Wr number of disk block
*/
int
sfs_clear_block(struct sfs_fs *sfs, uint32_t blkno, uint32_t nblks) {
int ret;
lock_sfs_io(sfs);
{
memset(sfs->sfs_buffer, 0, SFS_BLKSIZE);
while (nblks != 0) {
if ((ret = sfs_rwblock_nolock(sfs, sfs->sfs_buffer, blkno, 1, 1)) != 0) {
break;
}
blkno ++, nblks --;
}
}
unlock_sfs_io(sfs);
return ret;
}