jfs_dtree.c

jfs-2.4-1.1.7.tar.gz jfs 2.4－1.1.7 源码

 *	dtDeleteUp()
 *
 * function:
 *	free empty pages as propagating deletion up the tree
 *
 * parameter:
 *
 * return:
 */
static int dtDeleteUp(tid_t tid, struct inode *ip,
	   struct metapage * fmp, dtpage_t * fp, struct btstack * btstack)
{
	int rc = 0;
	struct metapage *mp;
	dtpage_t *p;
	int index, nextindex;
	int xlen;
	struct btframe *parent;
	struct dt_lock *dtlck;
	struct tlock *tlck;
	struct lv *lv;
	struct pxd_lock *pxdlock;
	int i;

	/*
	 *      keep the root leaf page which has become empty
	 */
	if (BT_IS_ROOT(fmp)) {
		/*
		 * reset the root
		 *
		 * dtInitRoot() acquires txlock on the root
		 */
		dtInitRoot(tid, ip, PARENT(ip));

		DT_PUTPAGE(fmp);

		return 0;
	}

	/*
	 *      free the non-root leaf page
	 */
	/*
	 * acquire a transaction lock on the page
	 *
	 * write FREEXTENT|NOREDOPAGE log record
	 * N.B. linelock is overlaid as freed extent descriptor, and
	 * the buffer page is freed;
	 */
	tlck = txMaplock(tid, ip, tlckDTREE | tlckFREE);
	pxdlock = (struct pxd_lock *) & tlck->lock;
	pxdlock->flag = mlckFREEPXD;
	pxdlock->pxd = fp->header.self;
	pxdlock->index = 1;

	/* update sibling pointers */
	if ((rc = dtRelink(tid, ip, fp))) {
		BT_PUTPAGE(fmp);
		return rc;
	}

	xlen = lengthPXD(&fp->header.self);
	ip->i_blocks -= LBLK2PBLK(ip->i_sb, xlen);

	/* free/invalidate its buffer page */
	discard_metapage(fmp);

	/*
	 *      propagate page deletion up the directory tree
	 *
	 * If the delete from the parent page makes it empty,
	 * continue all the way up the tree.
	 * stop if the root page is reached (which is never deleted) or
	 * if the entry deletion does not empty the page.
	 */
	while ((parent = BT_POP(btstack)) != NULL) {
		/* pin the parent page <sp> */
		DT_GETPAGE(ip, parent->bn, mp, PSIZE, p, rc);
		if (rc)
			return rc;

		/*
		 * free the extent of the child page deleted
		 */
		index = parent->index;

		/*
		 * delete the entry for the child page from parent
		 */
		nextindex = p->header.nextindex;

		/*
		 * the parent has the single entry being deleted:
		 *
		 * free the parent page which has become empty.
		 */
		if (nextindex == 1) {
			/*
			 * keep the root internal page which has become empty
			 */
			if (p->header.flag & BT_ROOT) {
				/*
				 * reset the root
				 *
				 * dtInitRoot() acquires txlock on the root
				 */
				dtInitRoot(tid, ip, PARENT(ip));

				DT_PUTPAGE(mp);

				return 0;
			}
			/*
			 * free the parent page
			 */
			else {
				/*
				 * acquire a transaction lock on the page
				 *
				 * write FREEXTENT|NOREDOPAGE log record
				 */
				tlck =
				    txMaplock(tid, ip,
					      tlckDTREE | tlckFREE);
				pxdlock = (struct pxd_lock *) & tlck->lock;
				pxdlock->flag = mlckFREEPXD;
				pxdlock->pxd = p->header.self;
				pxdlock->index = 1;

				/* update sibling pointers */
				if ((rc = dtRelink(tid, ip, p))) {
					DT_PUTPAGE(mp);
					return rc;
				}

				xlen = lengthPXD(&p->header.self);
				ip->i_blocks -= LBLK2PBLK(ip->i_sb, xlen);

				/* free/invalidate its buffer page */
				discard_metapage(mp);

				/* propagate up */
				continue;
			}
		}

		/*
		 * the parent has other entries remaining:
		 *
		 * delete the router entry from the parent page.
		 */
		BT_MARK_DIRTY(mp, ip);
		/*
		 * acquire a transaction lock on the page
		 *
		 * action: router entry deletion
		 */
		tlck = txLock(tid, ip, mp, tlckDTREE | tlckENTRY);
		dtlck = (struct dt_lock *) & tlck->lock;

		/* linelock header */
		if (dtlck->index >= dtlck->maxcnt)
			dtlck = (struct dt_lock *) txLinelock(dtlck);
		lv = & dtlck->lv[dtlck->index];
		lv->offset = 0;
		lv->length = 1;
		dtlck->index++;

		/* linelock stbl of non-root leaf page */
		if (!(p->header.flag & BT_ROOT)) {
			if (dtlck->index < dtlck->maxcnt)
				lv++;
			else {
				dtlck = (struct dt_lock *) txLinelock(dtlck);
				lv = & dtlck->lv[0];
			}
			i = index >> L2DTSLOTSIZE;
			lv->offset = p->header.stblindex + i;
			lv->length =
			    ((p->header.nextindex - 1) >> L2DTSLOTSIZE) -
			    i + 1;
			dtlck->index++;
		}

		/* free the router entry */
		dtDeleteEntry(p, index, &dtlck);

		/* reset key of new leftmost entry of level (for consistency) */
		if (index == 0 &&
		    ((p->header.flag & BT_ROOT) || p->header.prev == 0))
			dtTruncateEntry(p, 0, &dtlck);

		/* unpin the parent page */
		DT_PUTPAGE(mp);

		/* exit propagation up */
		break;
	}

	return 0;
}

#ifdef _NOTYET
/*
 * NAME:        dtRelocate()
 *
 * FUNCTION:    relocate dtpage (internal or leaf) of directory;
 *              This function is mainly used by defragfs utility.
 */
int dtRelocate(tid_t tid, struct inode *ip, s64 lmxaddr, pxd_t * opxd,
	       s64 nxaddr)
{
	int rc = 0;
	struct metapage *mp, *pmp, *lmp, *rmp;
	dtpage_t *p, *pp, *rp = 0, *lp= 0;
	s64 bn;
	int index;
	struct btstack btstack;
	pxd_t *pxd;
	s64 oxaddr, nextbn, prevbn;
	int xlen, xsize;
	struct tlock *tlck;
	struct dt_lock *dtlck;
	struct pxd_lock *pxdlock;
	s8 *stbl;
	struct lv *lv;

	oxaddr = addressPXD(opxd);
	xlen = lengthPXD(opxd);

	jfs_info("dtRelocate: lmxaddr:%Ld xaddr:%Ld:%Ld xlen:%d",
		   (long long)lmxaddr, (long long)oxaddr, (long long)nxaddr,
		   xlen);

	/*
	 *      1. get the internal parent dtpage covering
	 *      router entry for the tartget page to be relocated;
	 */
	rc = dtSearchNode(ip, lmxaddr, opxd, &btstack);
	if (rc)
		return rc;

	/* retrieve search result */
	DT_GETSEARCH(ip, btstack.top, bn, pmp, pp, index);
	jfs_info("dtRelocate: parent router entry validated.");

	/*
	 *      2. relocate the target dtpage
	 */
	/* read in the target page from src extent */
	DT_GETPAGE(ip, oxaddr, mp, PSIZE, p, rc);
	if (rc) {
		/* release the pinned parent page */
		DT_PUTPAGE(pmp);
		return rc;
	}

	/*
	 * read in sibling pages if any to update sibling pointers;
	 */
	rmp = NULL;
	if (p->header.next) {
		nextbn = le64_to_cpu(p->header.next);
		DT_GETPAGE(ip, nextbn, rmp, PSIZE, rp, rc);
		if (rc) {
			DT_PUTPAGE(mp);
			DT_PUTPAGE(pmp);
			return (rc);
		}
	}

	lmp = NULL;
	if (p->header.prev) {
		prevbn = le64_to_cpu(p->header.prev);
		DT_GETPAGE(ip, prevbn, lmp, PSIZE, lp, rc);
		if (rc) {
			DT_PUTPAGE(mp);
			DT_PUTPAGE(pmp);
			if (rmp)
				DT_PUTPAGE(rmp);
			return (rc);
		}
	}

	/* at this point, all xtpages to be updated are in memory */

	/*
	 * update sibling pointers of sibling dtpages if any;
	 */
	if (lmp) {
		tlck = txLock(tid, ip, lmp, tlckDTREE | tlckRELINK);
		dtlck = (struct dt_lock *) & tlck->lock;
		/* linelock header */
		ASSERT(dtlck->index == 0);
		lv = & dtlck->lv[0];
		lv->offset = 0;
		lv->length = 1;
		dtlck->index++;

		lp->header.next = cpu_to_le64(nxaddr);
		DT_PUTPAGE(lmp);
	}

	if (rmp) {
		tlck = txLock(tid, ip, rmp, tlckDTREE | tlckRELINK);
		dtlck = (struct dt_lock *) & tlck->lock;
		/* linelock header */
		ASSERT(dtlck->index == 0);
		lv = & dtlck->lv[0];
		lv->offset = 0;
		lv->length = 1;
		dtlck->index++;

		rp->header.prev = cpu_to_le64(nxaddr);
		DT_PUTPAGE(rmp);
	}

	/*
	 * update the target dtpage to be relocated
	 *
	 * write LOG_REDOPAGE of LOG_NEW type for dst page
	 * for the whole target page (logredo() will apply
	 * after image and update bmap for allocation of the
	 * dst extent), and update bmap for allocation of
	 * the dst extent;
	 */
	tlck = txLock(tid, ip, mp, tlckDTREE | tlckNEW);
	dtlck = (struct dt_lock *) & tlck->lock;
	/* linelock header */
	ASSERT(dtlck->index == 0);
	lv = & dtlck->lv[0];

	/* update the self address in the dtpage header */
	pxd = &p->header.self;
	PXDaddress(pxd, nxaddr);

	/* the dst page is the same as the src page, i.e.,
	 * linelock for afterimage of the whole page;
	 */
	lv->offset = 0;
	lv->length = p->header.maxslot;
	dtlck->index++;

	/* update the buffer extent descriptor of the dtpage */
	xsize = xlen << JFS_SBI(ip->i_sb)->l2bsize;
#ifdef _STILL_TO_PORT
	bmSetXD(mp, nxaddr, xsize);
#endif /* _STILL_TO_PORT */
	/* unpin the relocated page */
	DT_PUTPAGE(mp);
	jfs_info("dtRelocate: target dtpage relocated.");

	/* the moved extent is dtpage, then a LOG_NOREDOPAGE log rec
	 * needs to be written (in logredo(), the LOG_NOREDOPAGE log rec
	 * will also force a bmap update ).
	 */

	/*
	 *      3. acquire maplock for the source extent to be freed;
	 */
	/* for dtpage relocation, write a LOG_NOREDOPAGE record
	 * for the source dtpage (logredo() will init NoRedoPage
	 * filter and will also update bmap for free of the source
	 * dtpage), and upadte bmap for free of the source dtpage;
	 */
	tlck = txMaplock(tid, ip, tlckDTREE | tlckFREE);
	pxdlock = (struct pxd_lock *) & tlck->lock;
	pxdlock->flag = mlckFREEPXD;
	PXDaddress(&pxdlock->pxd, oxaddr);
	PXDlength(&pxdlock->pxd, xlen);
	pxdlock->index = 1;

	/*
	 *      4. update the parent router entry for relocation;
	 *
	 * acquire tlck for the parent entry covering the target dtpage;
	 * write LOG_REDOPAGE to apply after image only;
	 */
	jfs_info("dtRelocate: update parent router entry.");
	tlck = txLock(tid, ip, pmp, tlckDTREE | tlckENTRY);
	dtlck = (struct dt_lock *) & tlck->lock;
	lv = & dtlck->lv[dtlck->index];

	/* update the PXD with the new address */
	stbl = DT_GETSTBL(pp);
	pxd = (pxd_t *) & pp->slot[stbl[index]];
	PXDaddress(pxd, nxaddr);
	lv->offset = stbl[index];
	lv->length = 1;
	dtlck->index++;

	/* unpin the parent dtpage */
	DT_PUTPAGE(pmp);

	return rc;
}

/*
 * NAME:	dtSearchNode()
 *
 * FUNCTION:	Search for an dtpage containing a specified address
 *              This function is mainly used by defragfs utility.
 *
 * NOTE:	Search result on stack, the found page is pinned at exit.
 *		The result page must be an internal dtpage.
 *		lmxaddr give the address of the left most page of the
 *		dtree level, in which the required dtpage resides.
 */
static int dtSearchNode(struct inode *ip, s64 lmxaddr, pxd_t * kpxd,
			struct btstack * btstack)
{
	int rc = 0;
	s64 bn;
	struct metapage *mp;
	dtpage_t *p;
	int psize = 288;	/* initial in-line directory */
	s8 *stbl;
	int i;
	pxd_t *pxd;
	struct btframe *btsp;

	BT_CLR(btstack);	/* reset stack */

	/*
	 *      descend tree to the level with specified leftmost page
	 *
	 *  by convention, root bn = 0.
	 */
	for (bn = 0;;) {
		/* get/pin the page to search */
		DT_GETPAGE(ip, bn, mp, psize, p, rc);
		if (rc)
			return rc;

		/* does the xaddr of leftmost page of the levevl
		 * matches levevl search key ?
		 */
		if (p->header.flag & BT_ROOT) {
			if (lmxaddr == 0)
				break;
		} else if (addressPXD(&p->header.self) == lmxaddr)
			break;

		/*
		 * descend down to leftmost child page
		 */
		if (p->header.flag & BT_LEAF) {
			DT_PUTPAGE(mp);
			return -ESTALE;
		}

		/* get the leftmost entry */
		stbl = DT_GETSTBL(p);
		pxd = (pxd_t *) & p->slot[stbl[0]];

		/* get the child page block address */
		bn = addressPXD(pxd);
		psize = lengthPXD(pxd) << JFS_SBI(ip->i_sb)->l2bsize;
		/* unpin the parent page */
		DT_PUTPAGE(mp);
	}

	/*
	 *      search each page at the current levevl
	 */
      loop:
	stbl = DT_GETSTBL(p);
	for (i = 0; i < p->header.nextindex; i++) {
		pxd = (pxd_t *) & p->slot[stbl[i]];

		/* found the specified router entry */
		if (addressPXD(pxd) == addressPXD(kpxd) &&
		    lengthPXD(pxd) == lengthPXD(kpxd)) {
			btsp = btstack->top;
			btsp->bn = bn;
			btsp->index = i;
			btsp->mp = mp;

			return 0;
		}
	}

	/* get the right sibling page if any */
	if (p->header.next)
		bn = le64_to_cpu(p->header.next);
	else {
		DT_PUTPAGE(mp);
		return -ESTALE;
	}

	/* unpin current page */
	DT_PUTPAGE(mp);

	/* get the right sibling page */
	DT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
	if (rc)
		return rc;

	goto loop;
}
#endif /* _NOTYET */

/*
 *	dtRelink()
 *
 * function:
 *	link around a freed page.
 *
 * parameter:
 *	fp:	page to be freed
 *
 * return:
 */
static int dtRelink(tid_t tid, struct inode *ip, dtpage_t * p)
{
	int rc;
	struct metapage *mp;
	s64 nextbn, prevbn;
	struct tlock *tlck;
	struct dt_lock *dtlck;
	struct lv *lv;

	nextbn = le64_to_cpu(p->header.next);
	prevbn = le64_to_cpu(p->header.prev);

	/* update prev pointer of the next page */
	if (nextbn != 0) {
		DT_GETPAGE(ip, nextbn, mp, PSIZE, p, rc);
		if (rc)
			return rc;

		BT_MARK_DIRTY(mp, ip);
		/*
		 * acquire a transaction lock on the next page
		 *
		 * action: update prev pointer;
		 */
		tlck = txLock(tid, ip, mp, tlckDTREE | tlckRELINK);
		jfs_info("dtRelink nextbn: tlck = 0x%p, ip = 0x%p, mp=0x%p",
			tlck, ip, mp);
		dtlck = (struct dt_lock *) & tlck->lock;

		/* linelock header */
		if (dtlck->index >= dtlck->maxcnt)
			dtlck = (struct dt_lock *) txLinelock(dtlck);
		lv = & dtlck->lv[dtlck->index];
		lv->offset = 0;
		lv->length = 1;