On Thu, Aug 07, 2008 at 06:31:33AM +0800, Tao Ma wrote:
> +/*
> + * Add a new cluster for xattr storage.
> + *
> + * If the new cluster is contiguous with the previous one, it will be
> + * appended to the same extent record, and num_clusters will be updated.
> + * If not, we will insert a new extent for it and move some xattrs in
> + * the last cluster into the new allocated one.
> + * We also need to limit the maximum size of a btree leaf, otherwise we'll
> + * lose the benefits of hashing because we'll have to search large leaves.
> + * So now the maximum size is OCFS2_MAX_XATTR_TREE_LEAF_SIZE(or clustersize,
> + * if it's bigger).
> + *
> + * first_bh is the first block of the previous extent rec and header_bh
> + * indicates the bucket we will insert the new xattrs. They will be updated
> + * when the header_bh is moved into the new cluster.
> + */
> +static int ocfs2_add_new_xattr_cluster(struct inode *inode,
> + struct buffer_head *root_bh,
> + struct buffer_head **first_bh,
> + struct buffer_head **header_bh,
> + u32 *num_clusters,
> + u32 prev_cpos,
> + u64 prev_blkno,
> + int *extend)
> +{
> + int ret, credits;
> + u16 bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
> + u32 prev_clusters = *num_clusters;
> + u32 clusters_to_add = 1, bit_off, num_bits, v_start = 0;
> + u64 block;
> + handle_t *handle = NULL;
> + struct ocfs2_alloc_context *data_ac = NULL;
> + struct ocfs2_alloc_context *meta_ac = NULL;
> + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> + struct ocfs2_xattr_block *xb =
> + (struct ocfs2_xattr_block *)root_bh->b_data;
> + struct ocfs2_xattr_tree_root *xb_root = &xb->xb_attrs.xb_root;
> + struct ocfs2_extent_list *root_el = &xb_root->xt_list;
> + enum ocfs2_extent_tree_type type = OCFS2_XATTR_TREE_EXTENT;
> +
> + mlog(0, "Add new xattr cluster for %llu, previous xattr hash = %u, "
> + "previous xattr blkno = %llu\n",
> + (unsigned long long)OCFS2_I(inode)->ip_blkno,
> + prev_cpos, prev_blkno);
> +
> + ret = ocfs2_lock_allocators(inode, root_bh, root_el,
> + clusters_to_add, 0, &data_ac,
> + &meta_ac, type, NULL);
> + if (ret) {
> + mlog_errno(ret);
> + goto leave;
> + }
> +
> + credits = ocfs2_calc_extend_credits(osb->sb, root_el, clusters_to_add);
> + handle = ocfs2_start_trans(osb, credits);
> + if (IS_ERR(handle)) {
> + ret = PTR_ERR(handle);
> + handle = NULL;
> + mlog_errno(ret);
> + goto leave;
> + }
> +
> + ret = ocfs2_journal_access(handle, inode, root_bh,
> + OCFS2_JOURNAL_ACCESS_WRITE);
> + if (ret < 0) {
> + mlog_errno(ret);
> + goto leave;
> + }
> +
> + ret = __ocfs2_claim_clusters(osb, handle, data_ac, 1,
> + clusters_to_add, &bit_off, &num_bits);
> + if (ret < 0) {
> + if (ret != -ENOSPC)
> + mlog_errno(ret);
> + goto leave;
> + }
> +
> + BUG_ON(num_bits > clusters_to_add);
> +
> + block = ocfs2_clusters_to_blocks(osb->sb, bit_off);
> + mlog(0, "Allocating %u clusters at block %u for xattr in inode %llu\n",
> + num_bits, bit_off, (unsigned long long)OCFS2_I(inode)->ip_blkno);
> +
> + if (prev_blkno + prev_clusters * bpc == block &&
> + (prev_clusters + num_bits) << osb->s_clustersize_bits <=
> + OCFS2_MAX_XATTR_TREE_LEAF_SIZE) {
> + /*
> + * If this cluster is contiguous with the old one and
> + * adding this new cluster, we don't surpass the limit of
> + * OCFS2_MAX_XATTR_TREE_LEAF_SIZE, cool. We will let it be
> + * initialized and used like other buckets in the previous
> + * cluster.
> + * So add it as a contiguous one. The caller will handle
> + * its init process.
> + */
> + v_start = prev_cpos + prev_clusters;
> + *num_clusters = prev_clusters + num_bits;
> + mlog(0, "Add contiguous %u clusters to previous extent rec.\n",
> + num_bits);
> + } else {
> + ret = ocfs2_adjust_xattr_cross_cluster(inode,
> + handle,
> + first_bh,
> + header_bh,
> + block,
> + prev_blkno,
> + prev_clusters,
> + &v_start,
> + extend);
> + if (ret) {
> + mlog_errno(ret);
> + goto leave;
> + }
> + }
> +
> + mlog(0, "Insert %u clusters at block %llu for xattr at %u\n",
> + num_bits, block, v_start);
> + ret = ocfs2_xattr_tree_insert_extent(osb, handle, inode, root_bh,
> + v_start, block, num_bits,
> + 0, meta_ac);
I think we need to do something down in the extent insertion code to prevent
merging in the OCFS2_MAX_XATTR_TREE_LEAF_SIZE cases - what's preventing it
from appending that allocation to the end of an extent (any extent) in the
btree?
--Mark
--
Mark Fasheh
_______________________________________________
Ocfs2-devel mailing list
[email protected]
http://oss.oracle.com/mailman/listinfo/ocfs2-devel
