xfs_attr_leaf.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,154 行 · 第 1/5 页

	oldblk->hashval = xfs_attr_leaf_lasthash(oldblk->bp, NULL);
	newblk->hashval = xfs_attr_leaf_lasthash(newblk->bp, NULL);
	return(error);
}

/*
 * Add a name to the leaf attribute list structure.
 */
int
xfs_attr_leaf_add(xfs_dabuf_t *bp, xfs_da_args_t *args)
{
	xfs_attr_leafblock_t *leaf;
	xfs_attr_leaf_hdr_t *hdr;
	xfs_attr_leaf_map_t *map;
	int tablesize, entsize, sum, tmp, i;

	leaf = bp->data;
	ASSERT(INT_GET(leaf->hdr.info.magic, ARCH_CONVERT)
						== XFS_ATTR_LEAF_MAGIC);
	ASSERT((args->index >= 0)
		&& (args->index <= INT_GET(leaf->hdr.count, ARCH_CONVERT)));
	hdr = &leaf->hdr;
	entsize = xfs_attr_leaf_newentsize(args,
			   args->trans->t_mountp->m_sb.sb_blocksize, NULL);

	/*
	 * Search through freemap for first-fit on new name length.
	 * (may need to figure in size of entry struct too)
	 */
	tablesize = (INT_GET(hdr->count, ARCH_CONVERT) + 1)
					* sizeof(xfs_attr_leaf_entry_t)
					+ sizeof(xfs_attr_leaf_hdr_t);
	map = &hdr->freemap[XFS_ATTR_LEAF_MAPSIZE-1];
	for (sum = 0, i = XFS_ATTR_LEAF_MAPSIZE-1; i >= 0; map--, i--) {
		if (tablesize > INT_GET(hdr->firstused, ARCH_CONVERT)) {
			sum += INT_GET(map->size, ARCH_CONVERT);
			continue;
		}
		if (INT_ISZERO(map->size, ARCH_CONVERT))
			continue;	/* no space in this map */
		tmp = entsize;
		if (INT_GET(map->base, ARCH_CONVERT)
				< INT_GET(hdr->firstused, ARCH_CONVERT))
			tmp += sizeof(xfs_attr_leaf_entry_t);
		if (INT_GET(map->size, ARCH_CONVERT) >= tmp) {
			tmp = xfs_attr_leaf_add_work(bp, args, i);
			return(tmp);
		}
		sum += INT_GET(map->size, ARCH_CONVERT);
	}

	/*
	 * If there are no holes in the address space of the block,
	 * and we don't have enough freespace, then compaction will do us
	 * no good and we should just give up.
	 */
	if (!hdr->holes && (sum < entsize))
		return(XFS_ERROR(ENOSPC));

	/*
	 * Compact the entries to coalesce free space.
	 * This may change the hdr->count via dropping INCOMPLETE entries.
	 */
	xfs_attr_leaf_compact(args->trans, bp);

	/*
	 * After compaction, the block is guaranteed to have only one
	 * free region, in freemap[0].  If it is not big enough, give up.
	 */
	if (INT_GET(hdr->freemap[0].size, ARCH_CONVERT)
				< (entsize + sizeof(xfs_attr_leaf_entry_t)))
		return(XFS_ERROR(ENOSPC));

	return(xfs_attr_leaf_add_work(bp, args, 0));
}

/*
 * Add a name to a leaf attribute list structure.
 */
STATIC int
xfs_attr_leaf_add_work(xfs_dabuf_t *bp, xfs_da_args_t *args, int mapindex)
{
	xfs_attr_leafblock_t *leaf;
	xfs_attr_leaf_hdr_t *hdr;
	xfs_attr_leaf_entry_t *entry;
	xfs_attr_leaf_name_local_t *name_loc;
	xfs_attr_leaf_name_remote_t *name_rmt;
	xfs_attr_leaf_map_t *map;
	xfs_mount_t *mp;
	int tmp, i;

	leaf = bp->data;
	ASSERT(INT_GET(leaf->hdr.info.magic, ARCH_CONVERT)
						== XFS_ATTR_LEAF_MAGIC);
	hdr = &leaf->hdr;
	ASSERT((mapindex >= 0) && (mapindex < XFS_ATTR_LEAF_MAPSIZE));
	ASSERT((args->index >= 0)
		&& (args->index <= INT_GET(hdr->count, ARCH_CONVERT)));

	/*
	 * Force open some space in the entry array and fill it in.
	 */
	entry = &leaf->entries[args->index];
	if (args->index < INT_GET(hdr->count, ARCH_CONVERT)) {
		tmp  = INT_GET(hdr->count, ARCH_CONVERT) - args->index;
		tmp *= sizeof(xfs_attr_leaf_entry_t);
		memmove((char *)(entry+1), (char *)entry, tmp);
		xfs_da_log_buf(args->trans, bp,
		    XFS_DA_LOGRANGE(leaf, entry, tmp + sizeof(*entry)));
	}
	INT_MOD(hdr->count, ARCH_CONVERT, 1);

	/*
	 * Allocate space for the new string (at the end of the run).
	 */
	map = &hdr->freemap[mapindex];
	mp = args->trans->t_mountp;
	ASSERT(INT_GET(map->base, ARCH_CONVERT) < XFS_LBSIZE(mp));
	ASSERT((INT_GET(map->base, ARCH_CONVERT) & 0x3) == 0);
	ASSERT(INT_GET(map->size, ARCH_CONVERT)
				>= xfs_attr_leaf_newentsize(args,
					     mp->m_sb.sb_blocksize, NULL));
	ASSERT(INT_GET(map->size, ARCH_CONVERT) < XFS_LBSIZE(mp));
	ASSERT((INT_GET(map->size, ARCH_CONVERT) & 0x3) == 0);
	INT_MOD(map->size, ARCH_CONVERT,
		-xfs_attr_leaf_newentsize(args, mp->m_sb.sb_blocksize, &tmp));
	INT_SET(entry->nameidx, ARCH_CONVERT,
					INT_GET(map->base, ARCH_CONVERT)
				      + INT_GET(map->size, ARCH_CONVERT));
	INT_SET(entry->hashval, ARCH_CONVERT, args->hashval);
	entry->flags = tmp ? XFS_ATTR_LOCAL : 0;
	entry->flags |= (args->flags & ATTR_SECURE) ? XFS_ATTR_SECURE :
			((args->flags & ATTR_ROOT) ? XFS_ATTR_ROOT : 0);
	if (args->rename) {
		entry->flags |= XFS_ATTR_INCOMPLETE;
		if ((args->blkno2 == args->blkno) &&
		    (args->index2 <= args->index)) {
			args->index2++;
		}
	}
	xfs_da_log_buf(args->trans, bp,
			  XFS_DA_LOGRANGE(leaf, entry, sizeof(*entry)));
	ASSERT((args->index == 0) || (INT_GET(entry->hashval, ARCH_CONVERT)
						>= INT_GET((entry-1)->hashval,
							    ARCH_CONVERT)));
	ASSERT((args->index == INT_GET(hdr->count, ARCH_CONVERT)-1) ||
	       (INT_GET(entry->hashval, ARCH_CONVERT)
			    <= (INT_GET((entry+1)->hashval, ARCH_CONVERT))));

	/*
	 * Copy the attribute name and value into the new space.
	 *
	 * For "remote" attribute values, simply note that we need to
	 * allocate space for the "remote" value.  We can't actually
	 * allocate the extents in this transaction, and we can't decide
	 * which blocks they should be as we might allocate more blocks
	 * as part of this transaction (a split operation for example).
	 */
	if (entry->flags & XFS_ATTR_LOCAL) {
		name_loc = XFS_ATTR_LEAF_NAME_LOCAL(leaf, args->index);
		name_loc->namelen = args->namelen;
		INT_SET(name_loc->valuelen, ARCH_CONVERT, args->valuelen);
		memcpy((char *)name_loc->nameval, args->name, args->namelen);
		memcpy((char *)&name_loc->nameval[args->namelen], args->value,
				   INT_GET(name_loc->valuelen, ARCH_CONVERT));
	} else {
		name_rmt = XFS_ATTR_LEAF_NAME_REMOTE(leaf, args->index);
		name_rmt->namelen = args->namelen;
		memcpy((char *)name_rmt->name, args->name, args->namelen);
		entry->flags |= XFS_ATTR_INCOMPLETE;
		/* just in case */
		INT_ZERO(name_rmt->valuelen, ARCH_CONVERT);
		INT_ZERO(name_rmt->valueblk, ARCH_CONVERT);
		args->rmtblkno = 1;
		args->rmtblkcnt = XFS_B_TO_FSB(mp, args->valuelen);
	}
	xfs_da_log_buf(args->trans, bp,
	     XFS_DA_LOGRANGE(leaf, XFS_ATTR_LEAF_NAME(leaf, args->index),
				   xfs_attr_leaf_entsize(leaf, args->index)));

	/*
	 * Update the control info for this leaf node
	 */
	if (INT_GET(entry->nameidx, ARCH_CONVERT)
				< INT_GET(hdr->firstused, ARCH_CONVERT)) {
		/* both on-disk, don't endian-flip twice */
		hdr->firstused = entry->nameidx;
	}
	ASSERT(INT_GET(hdr->firstused, ARCH_CONVERT)
				>= ((INT_GET(hdr->count, ARCH_CONVERT)
					* sizeof(*entry))+sizeof(*hdr)));
	tmp = (INT_GET(hdr->count, ARCH_CONVERT)-1)
					* sizeof(xfs_attr_leaf_entry_t)
					+ sizeof(xfs_attr_leaf_hdr_t);
	map = &hdr->freemap[0];
	for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; map++, i++) {
		if (INT_GET(map->base, ARCH_CONVERT) == tmp) {
			INT_MOD(map->base, ARCH_CONVERT,
					sizeof(xfs_attr_leaf_entry_t));
			INT_MOD(map->size, ARCH_CONVERT,
					-sizeof(xfs_attr_leaf_entry_t));
		}
	}
	INT_MOD(hdr->usedbytes, ARCH_CONVERT,
				xfs_attr_leaf_entsize(leaf, args->index));
	xfs_da_log_buf(args->trans, bp,
		XFS_DA_LOGRANGE(leaf, hdr, sizeof(*hdr)));
	return(0);
}

/*
 * Garbage collect a leaf attribute list block by copying it to a new buffer.
 */
STATIC void
xfs_attr_leaf_compact(xfs_trans_t *trans, xfs_dabuf_t *bp)
{
	xfs_attr_leafblock_t *leaf_s, *leaf_d;
	xfs_attr_leaf_hdr_t *hdr_s, *hdr_d;
	xfs_mount_t *mp;
	char *tmpbuffer;

	mp = trans->t_mountp;
	tmpbuffer = kmem_alloc(XFS_LBSIZE(mp), KM_SLEEP);
	ASSERT(tmpbuffer != NULL);
	memcpy(tmpbuffer, bp->data, XFS_LBSIZE(mp));
	memset(bp->data, 0, XFS_LBSIZE(mp));

	/*
	 * Copy basic information
	 */
	leaf_s = (xfs_attr_leafblock_t *)tmpbuffer;
	leaf_d = bp->data;
	hdr_s = &leaf_s->hdr;
	hdr_d = &leaf_d->hdr;
	hdr_d->info = hdr_s->info;	/* struct copy */
	INT_SET(hdr_d->firstused, ARCH_CONVERT, XFS_LBSIZE(mp));
	/* handle truncation gracefully */
	if (INT_ISZERO(hdr_d->firstused, ARCH_CONVERT)) {
		INT_SET(hdr_d->firstused, ARCH_CONVERT,
				XFS_LBSIZE(mp) - XFS_ATTR_LEAF_NAME_ALIGN);
	}
	INT_ZERO(hdr_d->usedbytes, ARCH_CONVERT);
	INT_ZERO(hdr_d->count, ARCH_CONVERT);
	hdr_d->holes = 0;
	INT_SET(hdr_d->freemap[0].base, ARCH_CONVERT,
					sizeof(xfs_attr_leaf_hdr_t));
	INT_SET(hdr_d->freemap[0].size, ARCH_CONVERT,
				INT_GET(hdr_d->firstused, ARCH_CONVERT)
			      - INT_GET(hdr_d->freemap[0].base, ARCH_CONVERT));

	/*
	 * Copy all entry's in the same (sorted) order,
	 * but allocate name/value pairs packed and in sequence.
	 */
	xfs_attr_leaf_moveents(leaf_s, 0, leaf_d, 0,
				(int)INT_GET(hdr_s->count, ARCH_CONVERT), mp);

	xfs_da_log_buf(trans, bp, 0, XFS_LBSIZE(mp) - 1);

	kmem_free(tmpbuffer, XFS_LBSIZE(mp));
}

/*
 * Redistribute the attribute list entries between two leaf nodes,
 * taking into account the size of the new entry.
 *
 * NOTE: if new block is empty, then it will get the upper half of the
 * old block.  At present, all (one) callers pass in an empty second block.
 *
 * This code adjusts the args->index/blkno and args->index2/blkno2 fields
 * to match what it is doing in splitting the attribute leaf block.  Those
 * values are used in "atomic rename" operations on attributes.  Note that
 * the "new" and "old" values can end up in different blocks.
 */
STATIC void
xfs_attr_leaf_rebalance(xfs_da_state_t *state, xfs_da_state_blk_t *blk1,
				       xfs_da_state_blk_t *blk2)
{
	xfs_da_args_t *args;
	xfs_da_state_blk_t *tmp_blk;
	xfs_attr_leafblock_t *leaf1, *leaf2;
	xfs_attr_leaf_hdr_t *hdr1, *hdr2;
	int count, totallen, max, space, swap;

	/*
	 * Set up environment.
	 */
	ASSERT(blk1->magic == XFS_ATTR_LEAF_MAGIC);
	ASSERT(blk2->magic == XFS_ATTR_LEAF_MAGIC);
	leaf1 = blk1->bp->data;
	leaf2 = blk2->bp->data;
	ASSERT(INT_GET(leaf1->hdr.info.magic, ARCH_CONVERT)
						== XFS_ATTR_LEAF_MAGIC);
	ASSERT(INT_GET(leaf2->hdr.info.magic, ARCH_CONVERT)
						== XFS_ATTR_LEAF_MAGIC);
	args = state->args;

	/*
	 * Check ordering of blocks, reverse if it makes things simpler.
	 *
	 * NOTE: Given that all (current) callers pass in an empty
	 * second block, this code should never set "swap".
	 */
	swap = 0;
	if (xfs_attr_leaf_order(blk1->bp, blk2->bp)) {
		tmp_blk = blk1;
		blk1 = blk2;
		blk2 = tmp_blk;
		leaf1 = blk1->bp->data;
		leaf2 = blk2->bp->data;
		swap = 1;
	}
	hdr1 = &leaf1->hdr;
	hdr2 = &leaf2->hdr;

	/*
	 * Examine entries until we reduce the absolute difference in
	 * byte usage between the two blocks to a minimum.  Then get
	 * the direction to copy and the number of elements to move.
	 *
	 * "inleaf" is true if the new entry should be inserted into blk1.
	 * If "swap" is also true, then reverse the sense of "inleaf".
	 */
	state->inleaf = xfs_attr_leaf_figure_balance(state, blk1, blk2,
							    &count, &totallen);
	if (swap)
		state->inleaf = !state->inleaf;

	/*
	 * Move any entries required from leaf to leaf:
	 */
	if (count < INT_GET(hdr1->count, ARCH_CONVERT)) {
		/*
		 * Figure the total bytes to be added to the destination leaf.
		 */
		/* number entries being moved */
		count = INT_GET(hdr1->count, ARCH_CONVERT) - count;
		space  = INT_GET(hdr1->usedbytes, ARCH_CONVERT) - totallen;
		space += count * sizeof(xfs_attr_leaf_entry_t);

		/*
		 * leaf2 is the destination, compact it if it looks tight.
		 */
		max  = INT_GET(hdr2->firstused, ARCH_CONVERT)
						- sizeof(xfs_attr_leaf_hdr_t);
		max -= INT_GET(hdr2->count, ARCH_CONVERT)
					* sizeof(xfs_attr_leaf_entry_t);
		if (space > max) {
			xfs_attr_leaf_compact(args->trans, blk2->bp);
		}

		/*
		 * Move high entries from leaf1 to low end of leaf2.
		 */
		xfs_attr_leaf_moveents(leaf1,
				INT_GET(hdr1->count, ARCH_CONVERT)-count,
				leaf2, 0, count, state->mp);

		xfs_da_log_buf(args->trans, blk1->bp, 0, state->blocksize-1);
		xfs_da_log_buf(args->trans, blk2->bp, 0, state->blocksize-1);
	} else if (count > INT_GET(hdr1->count, ARCH_CONVERT)) {
		/*
		 * I assert that since all callers pass in an empty
		 * second buffer, this code should never execute.
		 */

		/*
		 * Figure the total bytes to be added to the destination leaf.
		 */
		/* number entries being moved */
		count -= INT_GET(hdr1->count, ARCH_CONVERT);
		space  = totallen - INT_GET(hdr1->usedbytes, ARCH_CONVERT);
		space += count * sizeof(xfs_attr_leaf_entry_t);

		/*
		 * leaf1 is the destination, compact it if it looks tight.
		 */
		max  = INT_GET(hdr1->firstused, ARCH_CONVERT)
						- sizeof(xfs_attr_leaf_hdr_t);
		max -= INT_GET(hdr1->count, ARCH_CONVERT)
					* sizeof(xfs_attr_leaf_entry_t);
		if (space > max) {
			xfs_attr_leaf_compact(args->trans, blk1->bp);
		}

		/*
		 * Move low entries from leaf2 to high end of leaf1.
		 */
		xfs_attr_leaf_moveents(leaf2, 0, leaf1,
				(int)INT_GET(hdr1->count, ARCH_CONVERT), count,
				state->mp);

		xfs_da_log_buf(args->trans, blk1->bp, 0, state->blocksize-1);
		xfs_da_log_buf(args->trans, blk2->bp, 0, state->blocksize-1);
	}

	/*
	 * Copy out last hashval in each block for B-tree code.
	 */
	blk1->hashval =
	    INT_GET(leaf1->entries[INT_GET(leaf1->hdr.count,
				    ARCH_CONVERT)-1].hashval, ARCH_CONVERT);
	blk2->hashval =
	    INT_GET(leaf2->entries[INT_GET(leaf2->hdr.count,
				    ARCH_CONVERT)-1].hashval, ARCH_CONVERT);

	/*
	 * Adjust the expected index for insertion.
	 * NOTE: this code depends on the (current) situation that the
	 * second block was originally empty.
	 *
	 * If the insertion point moved to the 2nd block, we must adjust
	 * the index.  We must also track the entry just following the
	 * new entry for use in an "atomic rename" operation, that entry
	 * is always the "old" entry and the "new" entry is what we are
	 * inserting.  The index/blkno fields refer to the "old" entry,
	 * while the index2/blkno2 fields refer to the "new" entry.
	 */
	if (blk1->index > INT_GET(leaf1->hdr.count, ARCH_CONVERT)) {
		ASSERT(state->inleaf == 0);
		blk2->index = blk1->index
				- INT_GET(leaf1->hdr.count, ARCH_CONVERT);
		args->index = args->index2 = blk2->index;
		args->blkno = args->blkno2 = blk2->blkno;
	} else if (blk1->index == INT_GET(leaf1->hdr.count, ARCH_CONVERT)) {
		if (state->inleaf) {
			args->index = blk1->index;
			args->blkno = blk1->blkno;
			args->index2 = 0;
			args->blkno2 = blk2->blkno;
		} else {