sanchayanmaity/xv6-cs450
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use ftable like btable and itable

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This commit is contained in:
rsc 2009-05-31 02:07:26 +00:00
parent ce72cadbe0
commit 7f399ccaa4
1 changed files with 21 additions and 22 deletions
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41
file.c
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@ -6,31 +6,32 @@
#include "dev.h"
struct devsw devsw[NDEV];
struct spinlock file_table_lock;
struct {
struct spinlock lock;
struct file file[NFILE];
} ftable;
void
fileinit(void)
{
initlock(&file_table_lock, "file_table");
initlock(&ftable.lock, "file_table");
}
// Allocate a file structure.
struct file*
filealloc(void)
{
int i;
struct file *f;
acquire(&file_table_lock);
for(i = 0; i < NFILE; i++){
if(file[i].type == FD_CLOSED){
file[i].type = FD_NONE;
file[i].ref = 1;
release(&file_table_lock);
return file + i;
acquire(&ftable.lock);
for(f = ftable.file; f < ftable.file + NFILE; f++){
if(f->ref == 0){
f->ref = 1;
release(&ftable.lock);
return f;
}
}
release(&file_table_lock);
release(&ftable.lock);
return 0;
}
@ -38,11 +39,11 @@ filealloc(void)
struct file*
filedup(struct file *f)
{
acquire(&file_table_lock);
if(f->ref < 1 || f->type == FD_CLOSED)
acquire(&ftable.lock);
if(f->ref < 1)
panic("filedup");
f->ref++;
release(&file_table_lock);
release(&ftable.lock);
return f;
}
@ -52,24 +53,22 @@ fileclose(struct file *f)
{
struct file ff;
acquire(&file_table_lock);
if(f->ref < 1 || f->type == FD_CLOSED)
acquire(&ftable.lock);
if(f->ref < 1)
panic("fileclose");
if(--f->ref > 0){
release(&file_table_lock);
release(&ftable.lock);
return;
}
ff = *f;
f->ref = 0;
f->type = FD_CLOSED;
release(&file_table_lock);
f->type = FD_NONE;
release(&ftable.lock);
if(ff.type == FD_PIPE)
pipeclose(ff.pipe, ff.writable);
else if(ff.type == FD_INODE)
iput(ff.ip);
else
panic("fileclose");
}
// Get metadata about file f.