vinumconfig.c

基于组件方式开发操作系统的OSKIT源代码

		    if (fe < (drive->freelist_entries - 1)) /* not the last one, */
			bcopy(&drive->freelist[fe + 1],
			    &drive->freelist[fe],
			    (drive->freelist_entries - fe) * sizeof(struct drive_freelist));
		    drive->freelist_entries--;		    /* one less entry */
		} else {
		    drive->freelist[fe].sectors -= sd->sectors;	/* this much less space */
		    drive->freelist[fe].offset += sd->sectors; /* this much further on */
		}
		drive->sectors_available -= sd->sectors;    /* and note how much less space we have */
		break;
	    }
	}
	if (sd->driveoffset < 0)
	    /*
	     * Didn't find anything.  Although the drive has
	     * enough space, it's too fragmented
	     */
	    throw_rude_remark(ENOSPC, "No space for %s on %s", sd->name, drive->label.name);
    } else {						    /* specific offset */
	/*
	 * For a specific offset to work, the space must be
	 * entirely in a single freelist entry.  Look for it.
	 */
	u_int64_t sdend = sd->driveoffset + sd->sectors;    /* end of our subdisk */
	for (fe = 0; fe < drive->freelist_entries; fe++) {
	    u_int64_t dend = drive->freelist[fe].offset + drive->freelist[fe].sectors; /* end of entry */
	    if (dend >= sdend) {			    /* fits before here */
		if (drive->freelist[fe].offset > sd->driveoffset) /* starts after the beginning of sd area */
		    throw_rude_remark(ENOSPC,
			"No space for subdisk %s on drive %s at offset %lld",
			sd->name,
			drive->label.name);

		/*
		 * We've found the space, and we can allocate it.
		 * We don't need to say that to the subdisk, which
		 * already knows about it.  We need to tell it to
		 * the free list, though.  We have four possibilities:
		 *
		 * 1.  The subdisk exactly eats up the entry.  That's the
		 *     same as above.
		 * 2.  The subdisk starts at the beginning and leaves space
		 *     at the end.
		 * 3.  The subdisk starts after the beginning and leaves
		 *     space at the end as well: we end up with another
		 *     fragment.
		 * 4.  The subdisk leaves space at the beginning and finishes
		 *     at the end.
		 */
		drive->sectors_available -= sd->sectors;    /* note how much less space we have */
		if (sd->driveoffset == drive->freelist[fe].offset) { /* 1 or 2 */
		    if (sd->sectors == drive->freelist[fe].sectors) { /* 1: used up the entire entry */
			if (fe < (drive->freelist_entries - 1))	/* not the last one, */
			    bcopy(&drive->freelist[fe + 1],
				&drive->freelist[fe],
				(drive->freelist_entries - fe) * sizeof(struct drive_freelist));
			drive->freelist_entries--;	    /* one less entry */
		    } else {				    /* 2: space at the end */
			drive->freelist[fe].sectors -= sd->sectors; /* this much less space */
			drive->freelist[fe].offset += sd->sectors; /* this much further on */
		    }
		} else {				    /* 3 or 4 */
		    drive->freelist[fe].sectors = sd->driveoffset - drive->freelist[fe].offset;
		    if (dend > sdend) {			    /* 3: space at the end as well */
			if (fe < (drive->freelist_entries - 1))	/* not the last one */
			    bcopy(&drive->freelist[fe],	    /* move the rest down */
				&drive->freelist[fe + 1],
				(drive->freelist_entries - fe) * sizeof(struct drive_freelist));
			drive->freelist_entries++;	    /* one less entry */
			drive->freelist[fe + 1].offset = sdend;	/* second entry starts after sd */
			drive->freelist[fe + 1].sectors = dend - sdend;	/* and is this long */
		    }
		}
		break;
	    }
	}
    }
    drive->opencount++;					    /* one more subdisk attached */
}

/* Get an empty drive entry from the drive table */
int 
get_empty_drive(void)
{
    int driveno;
    struct drive *drive;

    /* first see if we have one which has been deallocated */
    for (driveno = 0; driveno < vinum_conf.drives_allocated; driveno++) {
	if (DRIVE[driveno].state == drive_unallocated)	    /* bingo */
	    break;
    }

    if (driveno >= vinum_conf.drives_allocated)		    /* we've used all our allocation */
	EXPAND(DRIVE, struct drive, vinum_conf.drives_allocated, INITIAL_DRIVES);

    /* got a drive entry.  Make it pretty */
    drive = &DRIVE[driveno];
    bzero(drive, sizeof(struct drive));
    drive->driveno = driveno;				    /* put number in structure */
    drive->flags |= VF_NEWBORN;				    /* newly born drive */
    strcpy("unknown", drive->devicename);		    /* and make the name ``unknown'' */
    return driveno;					    /* return the index */
}

/*
 * Find the named drive in vinum_conf.drive, return a pointer
 * return the index in vinum_conf.drive.
 * Don't mark the drive as allocated (XXX SMP)
 * If create != 0, create an entry if it doesn't exist
 */
/* XXX check if we have it open from attach */
int 
find_drive(const char *name, int create)
{
    int driveno;
    struct drive *drive;

    if (name != NULL) {
	for (driveno = 0; driveno < vinum_conf.drives_allocated; driveno++) {
	    drive = &DRIVE[driveno];			    /* point to drive */
	    if ((drive->label.name[0] != '\0')		    /* it has a name */
&&(strcmp(drive->label.name, name) == 0)		    /* and it's this one */
	    &&(drive->state > drive_unallocated))	    /* and it's a real one: found */
		return driveno;
	}
    }
    /* the drive isn't in the list.  Add it if he wants */
    if (create == 0)					    /* don't want to create */
	return -1;					    /* give up */

    driveno = get_empty_drive();
    drive = &DRIVE[driveno];
    if (name != NULL)
	bcopy(name,					    /* put in its name */
	    drive->label.name,
	    min(sizeof(drive->label.name),
		strlen(name)));
    drive->state = drive_referenced;			    /* in use, nothing worthwhile there */
    return driveno;					    /* return the index */
}

/*
 * Find a drive given its device name.
 * devname must be valid.
 * Otherwise the same as find_drive above
 */
int 
find_drive_by_dev(const char *devname, int create)
{
    int driveno;
    struct drive *drive;

    for (driveno = 0; driveno < vinum_conf.drives_allocated; driveno++) {
	drive = &DRIVE[driveno];			    /* point to drive */
	if ((strcmp(drive->devicename, devname) == 0)	    /* it's this device */
	&&(drive->state > drive_unallocated))		    /* and it's a real one: found */
	    return driveno;
    }

    /* the drive isn't in the list.  Add it if he wants */
    if (create == 0)					    /* don't want to create */
	return -1;					    /* give up */

    driveno = get_empty_drive();
    drive = &DRIVE[driveno];
    bcopy(devname,					    /* put in its name */
	drive->devicename,
	min(sizeof(drive->devicename),
	    strlen(devname)));
    drive->state = drive_referenced;			    /* in use, nothing worthwhile there */
    return driveno;					    /* return the index */
}

/* Find an empty subdisk in the subdisk table */
int 
get_empty_sd(void)
{
    int sdno;
    struct sd *sd;

    /* first see if we have one which has been deallocated */
    for (sdno = 0; sdno < vinum_conf.subdisks_allocated; sdno++) {
	if (SD[sdno].state == sd_unallocated)		    /* bingo */
	    break;
    }
    if (sdno >= vinum_conf.subdisks_allocated)
	/*
	 * We've run out of space.  sdno is pointing
	 * where we want it, but at the moment we
	 * don't have the space.  Get it.
	 */
	EXPAND(SD, struct sd, vinum_conf.subdisks_allocated, INITIAL_SUBDISKS);

    /* initialize some things */
    sd = &SD[sdno];					    /* point to it */
    bzero(sd, sizeof(struct sd));			    /* initialize */
    sd->flags |= VF_NEWBORN;				    /* newly born subdisk */
    sd->plexno = -1;					    /* no plex */
    sd->driveno = -1;					    /* and no drive */
    sd->plexoffset = -1;				    /* and no offsets */
    sd->driveoffset = -1;
    return sdno;					    /* return the index */
}

/* return a drive to the free pool */
void 
free_drive(struct drive *drive)
{
    if (drive->state > drive_referenced) {		    /* real drive */
	LOCKDRIVE(drive);
	if (drive->vp != NULL)				    /* device open */
	    vn_close(drive->vp, FREAD | FWRITE, FSCRED, drive->p);
	if (drive->freelist)
	    Free(drive->freelist);
	bzero(drive, sizeof(struct drive));		    /* this also sets drive_unallocated */
	unlockdrive(drive);
    }
}

/*
 * Find the named subdisk in vinum_conf.sd.
 *
 * If create != 0, create an entry if it doesn't exist
 *
 * Return index in vinum_conf.sd
 */
int 
find_subdisk(const char *name, int create)
{
    int sdno;
    struct sd *sd;

    for (sdno = 0; sdno < vinum_conf.subdisks_allocated; sdno++) {
	if (strcmp(SD[sdno].name, name) == 0)		    /* found it */
	    return sdno;
    }

    /* the subdisk isn't in the list.  Add it if he wants */
    if (create == 0)					    /* don't want to create */
	return -1;					    /* give up */

    /* Allocate one and insert the name */
    sdno = get_empty_sd();
    sd = &SD[sdno];
    bcopy(name, sd->name, min(sizeof(sd->name), strlen(name)));	/* put in its name */
    return sdno;					    /* return the pointer */
}

/* Return space to a drive */
void 
return_drive_space(int driveno, int64_t offset, int length)
{
    struct drive *drive;
    int fe;						    /* free list entry */
    u_int64_t sdend;					    /* end of our subdisk */
    u_int64_t dend;					    /* end of our freelist entry */

    drive = &DRIVE[driveno];
    if (drive->state == drive_up) {
	sdend = offset + length;			    /* end of our subdisk */

	/* Look for where to return the sd address space */
	for (fe = 0;
	    (fe < drive->freelist_entries) && (drive->freelist[fe].offset < offset);
	    fe++);
	/*
	 * Now we are pointing to the last entry, the first
	 * with a higher offset than the subdisk, or both.
	 */
	if ((fe > 1)					    /* not the first entry */
&&((fe == drive->freelist_entries)			    /* gone past the end */
	||(drive->freelist[fe].offset > offset)))	    /* or past the block were looking for */
	    fe--;					    /* point to the block before */
	dend = drive->freelist[fe].offset + drive->freelist[fe].sectors; /* end of the entry */

	/*
	 * At this point, we are pointing to the correct
	 * place in the free list.  A number of possibilities
	 * exist:
	 *
	 * 1.  The block to be freed starts at the end of the
	 *     block to which we are pointing.  This has two
	 *     subcases:
	 *
	 * a.  The block to be freed ends at the beginning
	 *     of the following block.  Merge the three
	 *     areas into a single block.
	 *
	 * b.  The block is shorter than the space between
	 *     the current block and the next one.  Enlarge
	 *     the current block.
	 *
	 * 2.  The block to be freed starts after the end
	 *     of the block.  Again, we have two cases:
	 *
	 * a.  It ends before the start of the following block.
	 *     Create a new free block.
	 *
	 * b.  It ends at the start of the following block.
	 *     Enlarge the following block downwards.
	 *
	 * When there is only one free space block, and the
	 * space to be returned is before it, the pointer is
	 * to a non-existent zeroth block. XXX check this
	 */
	if (offset == dend) {				    /* Case 1: it starts at the end of this block */
	    if ((fe < drive->freelist_entries - 1)	    /* we're not the last block in the free list */
	    &&(sdend == drive->freelist[fe + 1].offset)) {  /* and the subdisk ends at the start of the
																			   * next block */
		drive->freelist[fe].sectors = drive->freelist[fe + 1].sectors; /* 1a: merge all three blocks */
		if (fe < drive->freelist_entries - 2)	    /* still more blocks after next */
		    bcopy(&drive->freelist[fe + 2],	    /* move down one */
			&drive->freelist[fe + 1],
			(drive->freelist_entries - 2 - fe) * sizeof(struct drive_freelist));
		drive->freelist_entries--;		    /* one less entry in the free list */
	    } else					    /* 1b: just enlarge this block */
		drive->freelist[fe].sectors += length;
	} else {					    /* Case 2 */
	    if (offset > dend)				    /* it starts after this block */
		fe++;					    /* so look at the next block */
	    if ((fe < drive->freelist_entries)		    /* we're not the last block in the free list */
	    &&(sdend == drive->freelist[fe].offset)) {	    /* and the subdisk ends at the start of
																		   * this block: case 4 */
		drive->freelist[fe].offset = offset;	    /* it starts where the sd was */
		drive->freelist[fe].sectors += length;	    /* and it's this much bigger */
	    } else {					    /* case 3: non-contiguous */
		if (fe < drive->freelist_entries)	    /* not after the last block, */
		    bcopy(&drive->freelist[fe],		    /* move the rest up one entry */
			&drive->freelist[fe + 1],
			(drive->freelist_entries - fe) * sizeof(struct drive_freelist));
		drive->freelist_entries++;		    /* one less entry */
		drive->freelist[fe].offset = offset;	    /* this entry represents the sd */
		drive->freelist[fe].sectors = length;
	    }
	}
	drive->sectors_available += length;		    /* the sectors are now available */
    }
}

/*
 * Free an allocated sd entry
 * This performs memory management only.  remove()
 * is responsible for checking relationships.
 */
void 
free_sd(int sdno)
{
    struct sd *sd;

    sd = &SD[sdno];
    if ((sd->driveno >= 0)				    /* we have a drive, */
    &&(sd->sectors > 0))				    /* and some space on it */
	return_drive_space(sd->driveno,			    /* return the space */
	    sd->driveoffset,
	    sd->sectors);
    bzero(sd, sizeof(struct sd));			    /* and clear it out */
    sd->state = sd_unallocated;
}

/* Find an empty plex in the plex table */
int 
get_empty_plex(void)
{
    int plexno;
    struct plex *plex;					    /* if we allocate one */

    /* first see if we have one which has been deallocated */
    for (plexno = 0; plexno < vinum_conf.plexes_allocated; plexno++) {
	if (PLEX[plexno].state == plex_unallocated)	    /* bingo */
	    break;					    /* and get out of here */
    }

    if (plexno >= vinum_conf.plexes_allocated)
	EXPAND(PLEX, struct plex, vinum_conf.plexes_allocated, INITIAL_PLEXES);

    /* Found a plex.  Give it an sd structure */
    plex = &PLEX[plexno];				    /* this one is ours */
    bzero(plex, sizeof(struct plex));			    /* polish it up */
    plex->sdnos = (int *) Malloc(sizeof(int) * INITIAL_SUBDISKS_IN_PLEX); /* allocate sd table */