From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tao Ma Date: Mon, 25 Jan 2010 10:12:34 +0800 Subject: [Ocfs2-devel] [PATCH 1/1] Ocfs2: Treat ocfs2 truncate as a special case of punching holes v1. In-Reply-To: <1264148107-9341-1-git-send-email-tristan.ye@oracle.com> References: <1264148107-9341-1-git-send-email-tristan.ye@oracle.com> Message-ID: <4B5CFE12.9010503@oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com Hi Tristan, Thanks for the work. Some comments inlined. Tristan Ye wrote: > As we known, truncate is just a special case of punching holes(from new i_size > to end), we therefore could take advantage of existing ocfs2_remove_extent() codes > to reduce the comlexity and redundancy in alloc.c, the goal here is to make truncate > codes more generic and straightforward. > > Several former functions only used by ocfs2_commit_truncate() will be simply wiped off. > New logic for truncating will remove extents from truncate_size to file end one by one, > just like punching holes did. > > v1 patch didn't include the codes for refcount supporting in truncate and holes punching, > it will be added in next series. > > Signed-off-by: Tristan Ye > --- > fs/ocfs2/alloc.c | 630 ++++-------------------------------------------------- > 1 files changed, 40 insertions(+), 590 deletions(-) > > diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c > index 38a42f5..8598452 100644 > --- a/fs/ocfs2/alloc.c > +++ b/fs/ocfs2/alloc.c > @@ -7409,198 +6986,73 @@ int ocfs2_commit_truncate(struct ocfs2_super *osb, > struct buffer_head *fe_bh, > struct ocfs2_truncate_context *tc) > { > - int status, i, credits, tl_sem = 0; > - u32 clusters_to_del, new_highest_cpos, range; > - u64 blkno = 0; > - struct ocfs2_extent_list *el; > - handle_t *handle = NULL; > - struct inode *tl_inode = osb->osb_tl_inode; > - struct ocfs2_path *path = NULL; > + int status, i; > + u32 trunc_start, trunc_end, trunc_len, cpos, phys_cpos, alloc_size; > struct ocfs2_dinode *di = (struct ocfs2_dinode *)fe_bh->b_data; > - struct ocfs2_alloc_context *meta_ac = NULL; > - struct ocfs2_refcount_tree *ref_tree = NULL; > + struct ocfs2_extent_tree et; > + struct buffer_head *eb_bh; > + struct ocfs2_extent_block *last_eb; > + struct ocfs2_extent_list *el; > > mlog_entry_void(); > > - new_highest_cpos = ocfs2_clusters_for_bytes(osb->sb, > - i_size_read(inode)); > - > - path = ocfs2_new_path(fe_bh, &di->id2.i_list, > - ocfs2_journal_access_di); > - if (!path) { > - status = -ENOMEM; > - mlog_errno(status); > - goto bail; > - } > - > - ocfs2_extent_map_trunc(inode, new_highest_cpos); > + ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), fe_bh); > > -start: > - /* > - * Check that we still have allocation to delete. > - */ > - if (OCFS2_I(inode)->ip_clusters == 0) { > - status = 0; > - goto bail; > - } > - > - credits = 0; > - > - /* > - * Truncate always works against the rightmost tree branch. > - */ > - status = ocfs2_find_path(INODE_CACHE(inode), path, UINT_MAX); > - if (status) { > - mlog_errno(status); > - goto bail; > - } > - > - mlog(0, "inode->ip_clusters = %u, tree_depth = %u\n", > - OCFS2_I(inode)->ip_clusters, path->p_tree_depth); > - > - /* > - * By now, el will point to the extent list on the bottom most > - * portion of this tree. Only the tail record is considered in > - * each pass. > - * > - * We handle the following cases, in order: > - * - empty extent: delete the remaining branch > - * - remove the entire record > - * - remove a partial record > - * - no record needs to be removed (truncate has completed) > - */ > - el = path_leaf_el(path); > - if (le16_to_cpu(el->l_next_free_rec) == 0) { > - ocfs2_error(inode->i_sb, > - "Inode %llu has empty extent block at %llu\n", > - (unsigned long long)OCFS2_I(inode)->ip_blkno, > - (unsigned long long)path_leaf_bh(path)->b_blocknr); > - status = -EROFS; > - goto bail; > - } > + trunc_start = ocfs2_clusters_for_bytes(osb->sb, i_size_read(inode)); > + if (le64_to_cpu(di->i_last_eb_blk)) { > + eb_bh = tc->tc_last_eb_bh; > + last_eb = (struct ocfs2_extent_block *)eb_bh->b_data; > + el = &last_eb->h_list; why not just check tc->tc_last_eb_bh? It is more readable. Say you check tc_last_eb_bh and then it has value, set el to it. btw, do we really need eb_bh? Minor issue. > + } else > + el = &di->id2.i_list; > > i = le16_to_cpu(el->l_next_free_rec) - 1; > - range = le32_to_cpu(el->l_recs[i].e_cpos) + > - ocfs2_rec_clusters(el, &el->l_recs[i]); > - if (i == 0 && ocfs2_is_empty_extent(&el->l_recs[i])) { > - clusters_to_del = 0; > - } else if (le32_to_cpu(el->l_recs[i].e_cpos) >= new_highest_cpos) { > - clusters_to_del = ocfs2_rec_clusters(el, &el->l_recs[i]); > - blkno = le64_to_cpu(el->l_recs[i].e_blkno); > - } else if (range > new_highest_cpos) { > - clusters_to_del = (ocfs2_rec_clusters(el, &el->l_recs[i]) + > - le32_to_cpu(el->l_recs[i].e_cpos)) - > - new_highest_cpos; > - blkno = le64_to_cpu(el->l_recs[i].e_blkno) + > - ocfs2_clusters_to_blocks(inode->i_sb, > - ocfs2_rec_clusters(el, &el->l_recs[i]) - > - clusters_to_del); > - } else { > - status = 0; > - goto bail; > - } > > - mlog(0, "clusters_to_del = %u in this pass, tail blk=%llu\n", > - clusters_to_del, (unsigned long long)path_leaf_bh(path)->b_blocknr); > + trunc_end = le32_to_cpu(el->l_recs[i].e_cpos) + > + ocfs2_rec_clusters(el, &el->l_recs[i]); > > - if (el->l_recs[i].e_flags & OCFS2_EXT_REFCOUNTED && clusters_to_del) { > - BUG_ON(!(OCFS2_I(inode)->ip_dyn_features & > - OCFS2_HAS_REFCOUNT_FL)); > + if (trunc_end >= trunc_start) > + trunc_len = trunc_end - trunc_start; > + else > + trunc_len = 0; > > - status = ocfs2_lock_refcount_tree(osb, > - le64_to_cpu(di->i_refcount_loc), > - 1, &ref_tree, NULL); > - if (status) { > - mlog_errno(status); > - goto bail; > - } > + cpos = trunc_start; > + while (trunc_len) { > > - status = ocfs2_prepare_refcount_change_for_del(inode, fe_bh, > - blkno, > - clusters_to_del, > - &credits, > - &meta_ac); > - if (status < 0) { > - mlog_errno(status); > + if (OCFS2_I(inode)->ip_clusters == 0) { > + status = 0; > goto bail; > } > - } > > - mutex_lock(&tl_inode->i_mutex); > - tl_sem = 1; > - /* ocfs2_truncate_log_needs_flush guarantees us at least one > - * record is free for use. If there isn't any, we flush to get > - * an empty truncate log. */ > - if (ocfs2_truncate_log_needs_flush(osb)) { > - status = __ocfs2_flush_truncate_log(osb); > - if (status < 0) { > + status = ocfs2_get_clusters(inode, cpos, &phys_cpos, > + &alloc_size, NULL); > + if (status) { > mlog_errno(status); > goto bail; > } > - } > > - credits += ocfs2_calc_tree_trunc_credits(osb->sb, clusters_to_del, > - (struct ocfs2_dinode *)fe_bh->b_data, > - el); > - handle = ocfs2_start_trans(osb, credits); > - if (IS_ERR(handle)) { > - status = PTR_ERR(handle); > - handle = NULL; > - mlog_errno(status); > - goto bail; > - } > + if (alloc_size > trunc_len) > + alloc_size = trunc_len; > > - status = ocfs2_do_truncate(osb, clusters_to_del, inode, fe_bh, handle, > - tc, path, meta_ac); > - if (status < 0) { > - mlog_errno(status); > - goto bail; > - } > - > - mutex_unlock(&tl_inode->i_mutex); > - tl_sem = 0; > - > - ocfs2_commit_trans(osb, handle); > - handle = NULL; > - > - ocfs2_reinit_path(path, 1); > - > - if (meta_ac) { > - ocfs2_free_alloc_context(meta_ac); > - meta_ac = NULL; > - } > + if (phys_cpos != 0) { > + status = ocfs2_remove_btree_range(inode, &et, cpos, > + phys_cpos, alloc_size, > + &tc->tc_dealloc); > + if (status) { > + mlog_errno(status); > + goto bail; > + } > + } I would really appreciate it if we can start from the end to the beginning. You know, if we start from cpos, when we remove an extent, the b-tree codes will try to rotate_tree_left. So if there are many extents for us to truncate, the performance will decrease a lot. While in the old implementation, we remove extents from the tail, so no b-tree rotation at all. Regards, Tao