From 4506cfb6f8cad594ac73e0df2b2961ca10dbd25e Mon Sep 17 00:00:00 2001 From: Ryan Ding Date: Fri, 25 Mar 2016 14:21:06 -0700 Subject: [PATCH] ocfs2: record UNWRITTEN extents when populate write desc To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock. There is still one issue in the direct write procedure. phase 1: alloc extent with UNWRITTEN flag phase 2: submit direct data to disk, add zero page to page cache phase 3: clear UNWRITTEN flag when data has been written to disk When there are 2 direct write A(0~3KB),B(4~7KB) writing to the same cluster 0~7KB (cluster size 8KB). Write request A arrive phase 2 first, it will zero the region (4~7KB). Before request A enter to phase 3, request B arrive phase 2, it will zero region (0~3KB). This is just like request B steps request A. To resolve this issue, we should let request B knows this cluster is already under zero, to prevent it from steps the previous write request. This patch will add function ocfs2_unwritten_check() to do this job. It will record all clusters that are under direct write(it will be recorded in the 'ip_unwritten_list' member of inode info), and prevent the later direct write writing to the same cluster to do the zero work again. Signed-off-by: Ryan Ding Reviewed-by: Junxiao Bi Cc: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/aops.c | 104 ++++++++++++++++++++++++++++++++++++++++++++--- fs/ocfs2/inode.c | 3 ++ fs/ocfs2/inode.h | 3 ++ fs/ocfs2/super.c | 1 + 4 files changed, 106 insertions(+), 5 deletions(-) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 7b268c357cf3..c29d06634fd6 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -1201,6 +1201,13 @@ int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno, #define OCFS2_MAX_CLUSTERS_PER_PAGE (PAGE_CACHE_SIZE / OCFS2_MIN_CLUSTERSIZE) +struct ocfs2_unwritten_extent { + struct list_head ue_node; + struct list_head ue_ip_node; + u32 ue_cpos; + u32 ue_phys; +}; + /* * Describe the state of a single cluster to be written to. */ @@ -1275,6 +1282,8 @@ struct ocfs2_write_ctxt { struct buffer_head *w_di_bh; struct ocfs2_cached_dealloc_ctxt w_dealloc; + + struct list_head w_unwritten_list; }; void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages) @@ -1313,8 +1322,25 @@ static void ocfs2_unlock_pages(struct ocfs2_write_ctxt *wc) ocfs2_unlock_and_free_pages(wc->w_pages, wc->w_num_pages); } -static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc) +static void ocfs2_free_unwritten_list(struct inode *inode, + struct list_head *head) +{ + struct ocfs2_inode_info *oi = OCFS2_I(inode); + struct ocfs2_unwritten_extent *dz = NULL, *tmp = NULL; + + list_for_each_entry_safe(dz, tmp, head, ue_node) { + list_del(&dz->ue_node); + spin_lock(&oi->ip_lock); + list_del(&dz->ue_ip_node); + spin_unlock(&oi->ip_lock); + kfree(dz); + } +} + +static void ocfs2_free_write_ctxt(struct inode *inode, + struct ocfs2_write_ctxt *wc) { + ocfs2_free_unwritten_list(inode, &wc->w_unwritten_list); ocfs2_unlock_pages(wc); brelse(wc->w_di_bh); kfree(wc); @@ -1346,6 +1372,7 @@ static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp, wc->w_large_pages = 0; ocfs2_init_dealloc_ctxt(&wc->w_dealloc); + INIT_LIST_HEAD(&wc->w_unwritten_list); *wcp = wc; @@ -1795,6 +1822,66 @@ static void ocfs2_set_target_boundaries(struct ocfs2_super *osb, } } +/* + * Check if this extent is marked UNWRITTEN by direct io. If so, we need not to + * do the zero work. And should not to clear UNWRITTEN since it will be cleared + * by the direct io procedure. + * If this is a new extent that allocated by direct io, we should mark it in + * the ip_unwritten_list. + */ +static int ocfs2_unwritten_check(struct inode *inode, + struct ocfs2_write_ctxt *wc, + struct ocfs2_write_cluster_desc *desc) +{ + struct ocfs2_inode_info *oi = OCFS2_I(inode); + struct ocfs2_unwritten_extent *dz = NULL, *new = NULL; + int ret = 0; + + if (!desc->c_needs_zero) + return 0; + +retry: + spin_lock(&oi->ip_lock); + /* Needs not to zero no metter buffer or direct. The one who is zero + * the cluster is doing zero. And he will clear unwritten after all + * cluster io finished. */ + list_for_each_entry(dz, &oi->ip_unwritten_list, ue_ip_node) { + if (desc->c_cpos == dz->ue_cpos) { + BUG_ON(desc->c_new); + desc->c_needs_zero = 0; + desc->c_clear_unwritten = 0; + goto unlock; + } + } + + if (wc->w_type != OCFS2_WRITE_DIRECT) + goto unlock; + + if (new == NULL) { + spin_unlock(&oi->ip_lock); + new = kmalloc(sizeof(struct ocfs2_unwritten_extent), + GFP_NOFS); + if (new == NULL) { + ret = -ENOMEM; + goto out; + } + goto retry; + } + /* This direct write will doing zero. */ + new->ue_cpos = desc->c_cpos; + new->ue_phys = desc->c_phys; + desc->c_clear_unwritten = 0; + list_add_tail(&new->ue_ip_node, &oi->ip_unwritten_list); + list_add_tail(&new->ue_node, &wc->w_unwritten_list); + new = NULL; +unlock: + spin_unlock(&oi->ip_lock); +out: + if (new) + kfree(new); + return ret; +} + /* * Populate each single-cluster write descriptor in the write context * with information about the i/o to be done. @@ -1879,6 +1966,12 @@ static int ocfs2_populate_write_desc(struct inode *inode, desc->c_needs_zero = 1; } + ret = ocfs2_unwritten_check(inode, wc, desc); + if (ret) { + mlog_errno(ret); + goto out; + } + num_clusters--; } @@ -2215,9 +2308,8 @@ int ocfs2_write_begin_nolock(struct address_space *mapping, * and non-sparse clusters we just extended. For non-sparse writes, * we know zeros will only be needed in the first and/or last cluster. */ - if (clusters_to_alloc || extents_to_split || - (wc->w_clen && (wc->w_desc[0].c_needs_zero || - wc->w_desc[wc->w_clen - 1].c_needs_zero))) + if (wc->w_clen && (wc->w_desc[0].c_needs_zero || + wc->w_desc[wc->w_clen - 1].c_needs_zero)) cluster_of_pages = 1; else cluster_of_pages = 0; @@ -2296,7 +2388,7 @@ int ocfs2_write_begin_nolock(struct address_space *mapping, ocfs2_commit_trans(osb, handle); out: - ocfs2_free_write_ctxt(wc); + ocfs2_free_write_ctxt(inode, wc); if (data_ac) { ocfs2_free_alloc_context(data_ac); @@ -2406,6 +2498,8 @@ int ocfs2_write_end_nolock(struct address_space *mapping, handle_t *handle = wc->w_handle; struct page *tmppage; + BUG_ON(!list_empty(&wc->w_unwritten_list)); + if (handle) { ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh, OCFS2_JOURNAL_ACCESS_WRITE); diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c index ba495beff1c2..12f4a9e9800f 100644 --- a/fs/ocfs2/inode.c +++ b/fs/ocfs2/inode.c @@ -1170,6 +1170,9 @@ static void ocfs2_clear_inode(struct inode *inode) mlog_bug_on_msg(!list_empty(&oi->ip_io_markers), "Clear inode of %llu, inode has io markers\n", (unsigned long long)oi->ip_blkno); + mlog_bug_on_msg(!list_empty(&oi->ip_unwritten_list), + "Clear inode of %llu, inode has unwritten extents\n", + (unsigned long long)oi->ip_blkno); ocfs2_extent_map_trunc(inode, 0); diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h index 01635e016b3e..68e8cf9bda97 100644 --- a/fs/ocfs2/inode.h +++ b/fs/ocfs2/inode.h @@ -57,6 +57,9 @@ struct ocfs2_inode_info u32 ip_flags; /* see below */ u32 ip_attr; /* inode attributes */ + /* Record unwritten extents during direct io. */ + struct list_head ip_unwritten_list; + /* protected by recovery_lock. */ struct inode *ip_next_orphan; diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c index ccc9386c42c5..d142fb75740e 100644 --- a/fs/ocfs2/super.c +++ b/fs/ocfs2/super.c @@ -1745,6 +1745,7 @@ static void ocfs2_inode_init_once(void *data) spin_lock_init(&oi->ip_lock); ocfs2_extent_map_init(&oi->vfs_inode); INIT_LIST_HEAD(&oi->ip_io_markers); + INIT_LIST_HEAD(&oi->ip_unwritten_list); oi->ip_dir_start_lookup = 0; mutex_init(&oi->ip_unaligned_aio); init_rwsem(&oi->ip_alloc_sem); -- 2.45.2