tfsclean3.c

完整的Bell实验室的嵌入式文件系统TFS

/* tfsclean3.c:
 *
 *  --- NOT READY YET ---
 *
 *  This version of defragmentation is power-hit safe and requires
 *  that there be double the amount of flash as is needed for use by
 *  TFS.  The basic idea is similar to tfsclean2.c...
 *  Copy all of the good files over to the "other" flash bank, then have
 *  TFS use the "other" bank as the storage area.
 *  The idea is that the defrag is simply a copy of the good stuff to
 *  the alternate flash block.  This requires that after the
 *  good stuff is copied, the now-dirty flash block must be erased in
 *  the background prior to the next tfsclean() call.  The fact that
 *  there is no sector erase is what makes this faster.
 *
 *  If both of these flash banks are in the same flash device, then
 *  having a background erase in progress means that it must be an
 *  interruptible erase (device specific).  This is necessary because
 *  while the background erase is in progress there may be a need to
 *  interact with the flash and most devices don't let you do both at the
 *  same time.
 *  
 *  Note that this "background-erase" is what makes this method the
 *  fastest defrag method.  It does require that the erase operation be
 *  interruptible, and it requires that the application will provide the
 *  hooks to do this...
 *
 *  General notice:
 *  This code is part of a boot-monitor package developed as a generic base
 *  platform for embedded system designs.  As such, it is likely to be
 *  distributed to various projects beyond the control of the original
 *  author.  Please notify the author of any enhancements made or bugs found
 *  so that all may benefit from the changes.  In addition, notification back
 *  to the author will allow the new user to pick up changes that may have
 *  been made by other users after this version of the code was distributed.
 *
 *  Note1: the majority of this code was edited with 4-space tabs.
 *  Note2: as more and more contributions are accepted, the term "author"
 *         is becoming a mis-representation of credit.
 *
 *  Original author:    Ed Sutter
 *  Email:              [e-mail]
 *  Phone:              908-582-2351
 */
#include "config.h"
#include "cpu.h"
#include "stddefs.h"
#include "genlib.h"
#include "tfs.h"
#include "tfsprivate.h"
#include "flash.h"
#include "monflags.h"

#if INCLUDE_TFS

int
tfsfixup(int verbose, int dontquery)
{
    return(TFSERR_NOTAVAILABLE);
}

#if DEFRAG_TEST_ENABLED
int
dumpDhdr(DEFRAGHDR *dhp)
{
    return(TFSERR_NOTAVAILABLE);
}

int
dumpDhdrTbl(DEFRAGHDR *dhp, int ftot)
{
    return(TFSERR_NOTAVAILABLE);
}
#endif


/* _tfsclean():
 *  This is an alternative to the complicated defragmentation above.
 *  It simply scans through the file list and copies all valid files
 *  to RAM; then flash is erased and the RAM is copied back to flash.
 *  <<< WARNING >>>
 *  THIS FUNCTION SHOULD NOT BE INTERRUPTED AND IT WILL BLOW AWAY
 *  ANY APPLICATION CURRENTLY IN CLIENT RAM SPACE.
 */
int
_tfsclean(TDEV *tdp, int notused, int verbose)
{
    TFILE   *tfp;
    uchar   *tbuf;
    ulong   appramstart;
    int     dtot, nfadd, len, err, chkstat;

    if (TfsCleanEnable < 0)
        return(TFSERR_CLEANOFF);

    appramstart = getAppRamStart();

    /* Determine how many "dead" files exist. */
    dtot = 0;
    tfp = (TFILE *)tdp->start;
    while(validtfshdr(tfp)) {
        if (!TFS_FILEEXISTS(tfp))
            dtot++;
        tfp = nextfp(tfp,tdp);
    }

    if (dtot == 0)
        return(TFS_OKAY);

    printf("Reconstructing device %s with %d dead file%s removed...\n",
        tdp->prefix, dtot,dtot>1 ? "s":"");

    tbuf = (char *)appramstart;
    tfp = (TFILE *)(tdp->start);
    nfadd = tdp->start;
    while(validtfshdr(tfp)) {
        if (TFS_FILEEXISTS(tfp)) {
            len = TFS_SIZE(tfp) + sizeof(struct tfshdr);
            if (len % TFS_FSIZEMOD)
                len += TFS_FSIZEMOD - (len % TFS_FSIZEMOD);
            nfadd += len;
            err = tfsmemcpy(tbuf,(uchar *)tfp,len,0,0);
            if (err != TFS_OKAY)
                return(err);
            
            ((struct tfshdr *)tbuf)->next = (struct tfshdr *)nfadd;
            tbuf += len;
        }
        tfp = nextfp(tfp,tdp);
    }

    /* Erase the flash device: */
    err = _tfsinit(tdp);
    if (err != TFS_OKAY)
        return(err);

    /* Copy data placed in RAM back to flash: */
    err = AppFlashWrite((ulong *)(tdp->start),(ulong *)appramstart,
        (tbuf-(uchar*)appramstart));
    if (err < 0)
        return(TFSERR_FLASHFAILURE);

    /* All defragmentation is done, so verify sanity of files... */
    chkstat = tfscheck(tdp,verbose);

    return(chkstat);
}
#endif