jfs_xtree.c

jfs-2.4-1.1.7.tar.gz jfs 2.4－1.1.7 源码

			/* init for parent page split */
			split->mp = smp;
			split->index = skip;	/* index at insert */
			split->flag = XAD_NEW;
			split->off = offsetXAD(&rcp->xad[XTENTRYSTART]);
			split->len = JFS_SBI(ip->i_sb)->nbperpage;
			split->addr = rcbn;

			/* unpin previous right child page */
			XT_PUTPAGE(rcmp);

			/* The split routines insert the new entry,
			 * and acquire txLock as appropriate.
			 * return <rp> pinned and its block number <rpbn>.
			 */
			rc = (sp->header.flag & BT_ROOT) ?
			    xtSplitRoot(tid, ip, split, &rmp) :
			    xtSplitPage(tid, ip, split, &rmp, &rbn);
			if (rc) {
				XT_PUTPAGE(smp);
				return rc;
			}

			XT_PUTPAGE(smp);
			/* keep new child page <rp> pinned */
		}
		/*
		 * parent page is not full - insert in parent page
		 */
		else {
			/*
			 * insert router entry in parent for the right child
			 * page from the first entry of the right child page:
			 */
			/*
			 * acquire a transaction lock on the parent page;
			 *
			 * action: router xad insertion;
			 */
			BT_MARK_DIRTY(smp, ip);

			/*
			 * if insert into middle, shift right remaining entries
			 */
			if (skip < nextindex)
				memmove(&sp->xad[skip + 1], &sp->xad[skip],
					(nextindex -
					 skip) << L2XTSLOTSIZE);

			/* insert the router entry */
			xad = &sp->xad[skip];
			XT_PUTENTRY(xad, XAD_NEW,
				    offsetXAD(&rcp->xad[XTENTRYSTART]),
				    JFS_SBI(ip->i_sb)->nbperpage, rcbn);

			/* advance next available entry index. */
			sp->header.nextindex =
			    cpu_to_le16(le16_to_cpu(sp->header.nextindex) +
					1);

			/* Don't log it if there are no links to the file */
			if (!test_cflag(COMMIT_Nolink, ip)) {
				tlck = txLock(tid, ip, smp,
					      tlckXTREE | tlckGROW);
				xtlck = (struct xtlock *) & tlck->lock;
				xtlck->lwm.offset = (xtlck->lwm.offset) ?
				    min(skip, (int)xtlck->lwm.offset) : skip;
				xtlck->lwm.length =
				    le16_to_cpu(sp->header.nextindex) -
				    xtlck->lwm.offset;
			}

			/* unpin parent page */
			XT_PUTPAGE(smp);

			/* exit propagate up */
			break;
		}
	}

	/* unpin current right page */
	XT_PUTPAGE(rmp);

	return 0;
}


/*
 *      xtSplitPage()
 *
 * function:
 *      split a full non-root page into
 *      original/split/left page and new right page
 *      i.e., the original/split page remains as left page.
 *
 * parameter:
 *      int		tid,
 *      struct inode    *ip,
 *      struct xtsplit  *split,
 *      struct metapage	**rmpp,
 *      u64		*rbnp,
 *
 * return:
 *      Pointer to page in which to insert or NULL on error.
 */
static int
xtSplitPage(tid_t tid, struct inode *ip,
	    struct xtsplit * split, struct metapage ** rmpp, s64 * rbnp)
{
	int rc = 0;
	struct metapage *smp;
	xtpage_t *sp;
	struct metapage *rmp;
	xtpage_t *rp;		/* new right page allocated */
	s64 rbn;		/* new right page block number */
	struct metapage *mp;
	xtpage_t *p;
	s64 nextbn;
	int skip, maxentry, middle, righthalf, n;
	xad_t *xad;
	struct pxdlist *pxdlist;
	pxd_t *pxd;
	struct tlock *tlck;
	struct xtlock *sxtlck = 0, *rxtlck = 0;

	smp = split->mp;
	sp = XT_PAGE(ip, smp);

	INCREMENT(xtStat.split);

	/*
	 * allocate the new right page for the split
	 */
	pxdlist = split->pxdlist;
	pxd = &pxdlist->pxd[pxdlist->npxd];
	pxdlist->npxd++;
	rbn = addressPXD(pxd);
	rmp = get_metapage(ip, rbn, PSIZE, 1);
	if (rmp == NULL)
		return -EIO;

	jfs_info("xtSplitPage: ip:0x%p smp:0x%p rmp:0x%p", ip, smp, rmp);

	BT_MARK_DIRTY(rmp, ip);
	/*
	 * action: new page;
	 */

	rp = (xtpage_t *) rmp->data;
	rp->header.self = *pxd;
	rp->header.flag = sp->header.flag & BT_TYPE;
	rp->header.maxentry = sp->header.maxentry;	/* little-endian */
	rp->header.nextindex = cpu_to_le16(XTENTRYSTART);

	BT_MARK_DIRTY(smp, ip);
	/* Don't log it if there are no links to the file */
	if (!test_cflag(COMMIT_Nolink, ip)) {
		/*
		 * acquire a transaction lock on the new right page;
		 */
		tlck = txLock(tid, ip, rmp, tlckXTREE | tlckNEW);
		rxtlck = (struct xtlock *) & tlck->lock;
		rxtlck->lwm.offset = XTENTRYSTART;
		/*
		 * acquire a transaction lock on the split page
		 */
		tlck = txLock(tid, ip, smp, tlckXTREE | tlckGROW);
		sxtlck = (struct xtlock *) & tlck->lock;
	}

	/*
	 * initialize/update sibling pointers of <sp> and <rp>
	 */
	nextbn = le64_to_cpu(sp->header.next);
	rp->header.next = cpu_to_le64(nextbn);
	rp->header.prev = cpu_to_le64(addressPXD(&sp->header.self));
	sp->header.next = cpu_to_le64(rbn);

	skip = split->index;

	/*
	 *      sequential append at tail (after last entry of last page)
	 *
	 * if splitting the last page on a level because of appending
	 * a entry to it (skip is maxentry), it's likely that the access is
	 * sequential. adding an empty page on the side of the level is less
	 * work and can push the fill factor much higher than normal.
	 * if we're wrong it's no big deal -  we will do the split the right
	 * way next time.
	 * (it may look like it's equally easy to do a similar hack for
	 * reverse sorted data, that is, split the tree left, but it's not.
	 * Be my guest.)
	 */
	if (nextbn == 0 && skip == le16_to_cpu(sp->header.maxentry)) {
		/*
		 * acquire a transaction lock on the new/right page;
		 *
		 * action: xad insertion;
		 */
		/* insert entry at the first entry of the new right page */
		xad = &rp->xad[XTENTRYSTART];
		XT_PUTENTRY(xad, split->flag, split->off, split->len,
			    split->addr);

		rp->header.nextindex = cpu_to_le16(XTENTRYSTART + 1);

		if (!test_cflag(COMMIT_Nolink, ip)) {
			/* rxtlck->lwm.offset = XTENTRYSTART; */
			rxtlck->lwm.length = 1;
		}

		*rmpp = rmp;
		*rbnp = rbn;

		ip->i_blocks += LBLK2PBLK(ip->i_sb, lengthPXD(pxd));

		jfs_info("xtSplitPage: sp:0x%p rp:0x%p", sp, rp);
		return 0;
	}

	/*
	 *      non-sequential insert (at possibly middle page)
	 */

	/*
	 * update previous pointer of old next/right page of <sp>
	 */
	if (nextbn != 0) {
		XT_GETPAGE(ip, nextbn, mp, PSIZE, p, rc);
		if (rc) {
			XT_PUTPAGE(rmp);
			return rc;
		}

		BT_MARK_DIRTY(mp, ip);
		/*
		 * acquire a transaction lock on the next page;
		 *
		 * action:sibling pointer update;
		 */
		if (!test_cflag(COMMIT_Nolink, ip))
			tlck = txLock(tid, ip, mp, tlckXTREE | tlckRELINK);

		p->header.prev = cpu_to_le64(rbn);

		/* sibling page may have been updated previously, or
		 * it may be updated later;
		 */

		XT_PUTPAGE(mp);
	}

	/*
	 * split the data between the split and new/right pages
	 */
	maxentry = le16_to_cpu(sp->header.maxentry);
	middle = maxentry >> 1;
	righthalf = maxentry - middle;

	/*
	 * skip index in old split/left page - insert into left page:
	 */
	if (skip <= middle) {
		/* move right half of split page to the new right page */
		memmove(&rp->xad[XTENTRYSTART], &sp->xad[middle],
			righthalf << L2XTSLOTSIZE);

		/* shift right tail of left half to make room for new entry */
		if (skip < middle)
			memmove(&sp->xad[skip + 1], &sp->xad[skip],
				(middle - skip) << L2XTSLOTSIZE);

		/* insert new entry */
		xad = &sp->xad[skip];
		XT_PUTENTRY(xad, split->flag, split->off, split->len,
			    split->addr);

		/* update page header */
		sp->header.nextindex = cpu_to_le16(middle + 1);
		if (!test_cflag(COMMIT_Nolink, ip)) {
			sxtlck->lwm.offset = (sxtlck->lwm.offset) ?
			    min(skip, (int)sxtlck->lwm.offset) : skip;
		}

		rp->header.nextindex =
		    cpu_to_le16(XTENTRYSTART + righthalf);
	}
	/*
	 * skip index in new right page - insert into right page:
	 */
	else {
		/* move left head of right half to right page */
		n = skip - middle;
		memmove(&rp->xad[XTENTRYSTART], &sp->xad[middle],
			n << L2XTSLOTSIZE);

		/* insert new entry */
		n += XTENTRYSTART;
		xad = &rp->xad[n];
		XT_PUTENTRY(xad, split->flag, split->off, split->len,
			    split->addr);

		/* move right tail of right half to right page */
		if (skip < maxentry)
			memmove(&rp->xad[n + 1], &sp->xad[skip],
				(maxentry - skip) << L2XTSLOTSIZE);

		/* update page header */
		sp->header.nextindex = cpu_to_le16(middle);
		if (!test_cflag(COMMIT_Nolink, ip)) {
			sxtlck->lwm.offset = (sxtlck->lwm.offset) ?
			    min(middle, (int)sxtlck->lwm.offset) : middle;
		}

		rp->header.nextindex = cpu_to_le16(XTENTRYSTART +
						   righthalf + 1);
	}

	if (!test_cflag(COMMIT_Nolink, ip)) {
		sxtlck->lwm.length = le16_to_cpu(sp->header.nextindex) -
		    sxtlck->lwm.offset;

		/* rxtlck->lwm.offset = XTENTRYSTART; */
		rxtlck->lwm.length = le16_to_cpu(rp->header.nextindex) -
		    XTENTRYSTART;
	}

	*rmpp = rmp;
	*rbnp = rbn;

	ip->i_blocks += LBLK2PBLK(ip->i_sb, lengthPXD(pxd));

	jfs_info("xtSplitPage: sp:0x%p rp:0x%p", sp, rp);
	return rc;
}


/*
 *      xtSplitRoot()
 *
 * function:
 *      split the full root page into
 *      original/root/split page and new right page
 *      i.e., root remains fixed in tree anchor (inode) and
 *      the root is copied to a single new right child page
 *      since root page << non-root page, and
 *      the split root page contains a single entry for the
 *      new right child page.
 *
 * parameter:
 *      int		tid,
 *      struct inode    *ip,
 *      struct xtsplit  *split,
 *      struct metapage	**rmpp)
 *
 * return:
 *      Pointer to page in which to insert or NULL on error.
 */
static int
xtSplitRoot(tid_t tid,
	    struct inode *ip, struct xtsplit * split, struct metapage ** rmpp)
{
	xtpage_t *sp;
	struct metapage *rmp;
	xtpage_t *rp;
	s64 rbn;
	int skip, nextindex;
	xad_t *xad;
	pxd_t *pxd;
	struct pxdlist *pxdlist;
	struct tlock *tlck;
	struct xtlock *xtlck;

	sp = &JFS_IP(ip)->i_xtroot;

	INCREMENT(xtStat.split);

	/*
	 *      allocate a single (right) child page
	 */
	pxdlist = split->pxdlist;
	pxd = &pxdlist->pxd[pxdlist->npxd];
	pxdlist->npxd++;
	rbn = addressPXD(pxd);
	rmp = get_metapage(ip, rbn, PSIZE, 1);
	if (rmp == NULL)
		return -EIO;

	jfs_info("xtSplitRoot: ip:0x%p rmp:0x%p", ip, rmp);

	/*
	 * acquire a transaction lock on the new right page;
	 *
	 * action: new page;
	 */
	BT_MARK_DIRTY(rmp, ip);

	rp = (xtpage_t *) rmp->data;
	rp->header.flag =
	    (sp->header.flag & BT_LEAF) ? BT_LEAF : BT_INTERNAL;
	rp->header.self = *pxd;
	rp->header.nextindex = cpu_to_le16(XTENTRYSTART);
	rp->header.maxentry = cpu_to_le16(PSIZE >> L2XTSLOTSIZE);

	/* initialize sibling pointers */
	rp->header.next = 0;
	rp->header.prev = 0;

	/*
	 * copy the in-line root page into new right page extent
	 */
	nextindex = le16_to_cpu(sp->header.maxentry);
	memmove(&rp->xad[XTENTRYSTART], &sp->xad[XTENTRYSTART],
		(nextindex - XTENTRYSTART) << L2XTSLOTSIZE);

	/*
	 * insert the new entry into the new right/child page
	 * (skip index in the new right page will not change)
	 */
	skip = split->index;
	/* if insert into middle, shift right remaining entries */
	if (skip != nextindex)
		memmove(&rp->xad[skip + 1], &rp->xad[skip],
			(nextindex - skip) * sizeof(xad_t));

	xad = &rp->xad[skip];
	XT_PUTENTRY(xad, split->flag, split->off, split->len, split->addr);

	/* update page header */
	rp->header.nextindex = cpu_to_le16(nextindex + 1);

	if (!test_cflag(COMMIT_Nolink, ip)) {
		tlck = txLock(tid, ip, rmp, tlckXTREE | tlckNEW);
		xtlck = (struct xtlock *) & tlck->lock;
		xtlck->lwm.offset = XTENTRYSTART;
		xtlck->lwm.length = le16_to_cpu(rp->header.nextindex) -
		    XTENTRYSTART;
	}

	/*
	 *      reset the root
	 *
	 * init root with the single entry for the new right page
	 * set the 1st entry offset to 0, which force the left-most key
	 * at any level of the tree to be less than any search key.
	 */
	/*
	 * acquire a transaction lock on the root page (in-memory inode);
	 *
	 * action: root split;
	 */
	BT_MARK_DIRTY(split->mp, ip);

	xad = &sp->xad[XTENTRYSTART];
	XT_PUTENTRY(xad, XAD_NEW, 0, JFS_SBI(ip->i_sb)->nbperpage, rbn);

	/* update page header of root */
	sp->header.flag &= ~BT_LEAF;
	sp->header.flag |= BT_INTERNAL;

	sp->header.nextindex = cpu_to_le16(XTENTRYSTART + 1);

	if (!test_cflag(COMMIT_Nolink, ip)) {
		tlck = txLock(tid, ip, split->mp, tlckXTREE | tlckGROW);
		xtlck = (struct xtlock *) & tlck->lock;
		xtlck->lwm.offset = XTENTRYSTART;
		xtlck->lwm.length = 1;
	}

	*rmpp = rmp;

	ip->i_blocks += LBLK2PBLK(ip->i_sb, lengthPXD(pxd));

	jfs_info("xtSplitRoot: sp:0x%p rp:0x%p", sp, rp);
	return 0;
}


/*
 *      xtExtend()
 *
 * function: extend in-place;
 *
 * note: existing extent may or may not have been committed.
 * caller is responsible for pager buffer cache update, and
 * working block allocation map update;
 * update pmap: alloc whole extended extent;
 */
int xtExtend(tid_t tid,		/* transaction id */
	     struct inode *ip, s64 xoff,	/* delta extent offset */
	     s32 xlen,		/* delta extent length */
	     int flag)
{
	int rc = 0;
	int cmp;
	struct metapage *mp;	/* meta-page buffer */
	xtpage_t *p;		/* base B+-tree index page */
	s64 bn;
	int index, nextindex, len;
	struct btstack btstack;	/* traverse stack */
	struct xtsplit split;	/* split information */
	xad_t *xad;
	s64 xaddr;
	struct tlock *tlck;
	struct xtlock *xtlck = 0;
	int rootsplit = 0;

	jfs_info("xtExtend: nxoff:0x%lx nxlen:0x%x", (ulong) xoff, xlen);

	/* there must exist extent to be extended */
	if ((rc = xtSearch(ip, xoff - 1, &cmp, &btstack, XT_INSERT)))
		return rc;

	/* retrieve search result */
	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);

	if (cmp != 0) {
		XT_PUTPAGE(mp);
		jfs_error(ip->i_sb, "xtExtend: xtSearch did not find extent");
		return -EIO;
	}

	/* extension must be contiguous */
	xad = &p->xad[index];
	if ((offsetXAD(xad) + lengthXAD(xad)) != xoff) {
		XT_PUTPAGE(mp);
		jfs_error(ip->i_sb, "xtExtend: extension is not contiguous");
		return -EIO;
	}

	/*
	 * acquire a transaction lock on the leaf page;
	 *
	 * action: xad insertion/extension;
	 */
	BT_MARK_DIRTY(mp, ip);
	if (!test_cflag(COMMIT_Nolink, ip)) {
		tlck = txLock(tid, ip, mp, tlckXTREE | tlckGROW);
		xtlck = (struct xtlock *) & tlck->lock;
	}

	/* extend will overflow extent ? */
	xlen = lengthXAD(xad) + xlen;
	if ((len = xlen - MAXXLEN) <= 0)
		goto extendOld;