lfdballoc.c File Reference

ディスク上の空きリストから新しいデータブロック割当を行う。 More...

#include <xinu.h>

Include dependency graph for lfdballoc.c:

Go to the source code of this file.

Macros
#define	DFILL   '+' /* character used to fill a disk block */

Functions
dbid32	lfdballoc (struct lfdbfree *dbuff)

Detailed Description

ディスク上の空きリストから新しいデータブロック割当を行う。

Definition in file lfdballoc.c.

Macro Definition Documentation

DFILL

#define DFILL   '+' /* character used to fill a disk block */

Definition at line 12 of file lfdballoc.c.

Referenced by lfdballoc().

Function Documentation

lfdballoc()

dbid32 lfdballoc

(

struct lfdbfree *

dbuff

)

Definition at line 19 of file lfdballoc.c.

References DFILL, FALSE, LF_AREA_DIR, LF_BLKSIZ, Lf_data, lfdata::lf_dir, lfdata::lf_dirdirty, LF_DNULL, lfdata::lf_dskdev, lfdir::lfd_dfree, memset(), panic(), read(), SYSERR, and write().

Referenced by lfsetup().

{
    dbid32 dnum;  /* ID of next d-block on the free list    */
    int32 retval; /* Return value               */

    /* Get the ID of first data block on the free list */

    dnum = Lf_data.lf_dir.lfd_dfree;
    if (dnum == LF_DNULL)
    { /* Ran out of free data blocks */
        panic("out of data blocks");
    }
    retval = read(Lf_data.lf_dskdev, (char *)dbuff, dnum);
    if (retval == SYSERR)
    {
        panic("lfdballoc cannot read disk block\n\r");
    }

    /* Unlink d-block from in-memory directory */

    Lf_data.lf_dir.lfd_dfree = dbuff->lf_nextdb;
    write(Lf_data.lf_dskdev, (char *)&Lf_data.lf_dir, LF_AREA_DIR);
    Lf_data.lf_dirdirty = FALSE;

    /* Fill data block to erase old data */

    memset((char *)dbuff, DFILL, LF_BLKSIZ);
    return dnum;
}

Here is the call graph for this function:

Here is the caller graph for this function: