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In case of "not sure" if the removable media has changed, the

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IBM PCDOS technical reference says to call BLDBPB if there are no used
buffers, so we only do it then, instead of flushing the buffers.


git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@1458 6ac86273-5f31-0410-b378-82cca8765d1b
This commit is contained in:
Bart Oldeman 2009-06-26 20:12:33 +00:00
parent e597bb20d4
commit 924f6d1bfd
3 changed files with 23 additions and 2 deletions
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18
kernel/blockio.c
View File

@ -259,6 +259,24 @@ VOID setinvld(REG COUNT dsk)
while (FP_OFF(bp) != FP_OFF(firstbuf));
}
/* Check if there is at least one dirty buffer */
/* */
BOOL dirty_buffers(REG COUNT dsk)
{
struct buffer FAR *bp = firstbuf;
do
{
if (bp->b_unit == dsk &&
(bp->b_flag & (BFR_VALID | BFR_DIRTY)) == (BFR_VALID | BFR_DIRTY))
return TRUE;
bp = b_next(bp);
}
while (FP_OFF(bp) != FP_OFF(firstbuf));
return FALSE;
}
/* */
/* */
/* Flush all buffers for a disk */
/* */

6
kernel/fatfs.c
View File

@ -1687,8 +1687,10 @@ COUNT media_check(REG struct dpb FAR * dpbp)
/* If it is forced or the media may have changed, */
/* rebuild the bpb */
case M_DONT_KNOW:
/* hazard: no error checking! */
flush_buffers(dpbp->dpb_unit);
/* IBM PCDOS technical reference says to call BLDBPB if */
/* there are no used buffers */
if (dirty_buffers(dpbp->dpb_unit))
return SUCCESS;
/* If it definitely changed, don't know (falls through) */
/* or has been changed, rebuild the bpb. */

1
kernel/proto.h
View File

@ -38,6 +38,7 @@ struct buffer FAR *getblk(ULONG blkno, COUNT dsk, BOOL overwrite);
#define getblock(blkno, dsk) getblk(blkno, dsk, FALSE);
#define getblockOver(blkno, dsk) getblk(blkno, dsk, TRUE);
VOID setinvld(REG COUNT dsk);
BOOL dirty_buffers(REG COUNT dsk);
BOOL flush_buffers(REG COUNT dsk);
BOOL flush(void);
BOOL fill(REG struct buffer FAR * bp, ULONG blkno, COUNT dsk);