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Commit 2242c689 authored by Adrian Hunter's avatar Adrian Hunter Committed by Artem Bityutskiy
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UBIFS: improve znode splitting rules 



When inserting into a full znode it is split into two
znodes.  Because data node keys are usually consecutive,
it is better to try to keep them together.  This patch
does a better job of that.

Signed-off-by: default avatarAdrian Hunter <ext-adrian.hunter@nokia.com>
parent 2953e73f

fs/ubifs/tnc.c

+33 −21
Original line number Diff line number Diff line
@@ -1962,7 +1962,7 @@ static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode, 
{

	struct ubifs_znode *zn, *zi, *zp;

	int i, keep, move, appending = 0;

	union ubifs_key *key = &zbr->key;

	union ubifs_key *key = &zbr->key, *key1;



	ubifs_assert(n >= 0 && n <= c->fanout);
@@ -2003,20 +2003,33 @@ static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode, 
	zn->level = znode->level;



	/* Decide where to split */

	if (znode->level == 0 && n == c->fanout &&

	    key_type(c, key) == UBIFS_DATA_KEY) {

		union ubifs_key *key1;



		/*

		 * If this is an inode which is being appended - do not split

		 * it because no other zbranches can be inserted between

		 * zbranches of consecutive data nodes anyway.

		 */

	if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {

		/* Try not to split consecutive data keys */

		if (n == c->fanout) {

			key1 = &znode->zbranch[n - 1].key;

			if (key_inum(c, key1) == key_inum(c, key) &&

		    key_type(c, key1) == UBIFS_DATA_KEY &&

		    key_block(c, key1) == key_block(c, key) - 1)

			    key_type(c, key1) == UBIFS_DATA_KEY)

				appending = 1;

		} else

			goto check_split;

	} else if (appending && n != c->fanout) {

		/* Try not to split consecutive data keys */

		appending = 0;

check_split:

		if (n >= (c->fanout + 1) / 2) {

			key1 = &znode->zbranch[0].key;

			if (key_inum(c, key1) == key_inum(c, key) &&

			    key_type(c, key1) == UBIFS_DATA_KEY) {

				key1 = &znode->zbranch[n].key;

				if (key_inum(c, key1) != key_inum(c, key) ||

				    key_type(c, key1) != UBIFS_DATA_KEY) {

					keep = n;

					move = c->fanout - keep;

					zi = znode;

					goto do_split;

				}

			}

		}

	}



	if (appending) {
@@ -2046,6 +2059,8 @@ static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode, 
			zbr->znode->parent = zn;

	}



do_split:



	__set_bit(DIRTY_ZNODE, &zn->flags);

	atomic_long_inc(&c->dirty_zn_cnt);
@@ -2072,14 +2087,11 @@ static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode, 


	/* Insert new znode (produced by spitting) into the parent */

	if (zp) {

		i = n;

		if (n == 0 && zi == znode && znode->iip == 0)

			correct_parent_keys(c, znode);



		/* Locate insertion point */

		n = znode->iip + 1;

		if (appending && n != c->fanout)

			appending = 0;



		if (i == 0 && zi == znode && znode->iip == 0)

			correct_parent_keys(c, znode);



		/* Tail recursion */

		zbr->key = zn->zbranch[0].key;