From b46637d59f1160dee5d8e03498e667ab36c2be04 Mon Sep 17 00:00:00 2001 From: Ryan Ding Date: Fri, 25 Mar 2016 14:20:55 -0700 Subject: [PATCH] ocfs2: use c_new to indicate newly allocated extents To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock. There is a problem in ocfs2's direct io implement: if system crashed after extents allocated, and before data return, we will get a extent with dirty data on disk. This problem violate the journal=order semantics, which means meta changes take effect after data written to disk. To resolve this issue, direct write can use the UNWRITTEN flag to describe a extent during direct data writeback. The direct write procedure should act in the following order: 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 This patch is to change the 'c_unwritten' member of ocfs2_write_cluster_desc to 'c_clear_unwritten'. Means whether to clear the unwritten flag. It do not care if a extent is allocated or not. And use 'c_new' to specify a newly allocated extent. So the direct io procedure can use c_clear_unwritten to control the UNWRITTEN bit on extent. 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 | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 69d7392f56d8..516ea896f13c 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -1212,7 +1212,7 @@ struct ocfs2_write_cluster_desc { * filled. */ unsigned c_new; - unsigned c_unwritten; + unsigned c_clear_unwritten; unsigned c_needs_zero; }; @@ -1588,19 +1588,19 @@ out: * Prepare a single cluster for write one cluster into the file. */ static int ocfs2_write_cluster(struct address_space *mapping, - u32 phys, unsigned int unwritten, + u32 phys, unsigned int new, + unsigned int clear_unwritten, unsigned int should_zero, struct ocfs2_alloc_context *data_ac, struct ocfs2_alloc_context *meta_ac, struct ocfs2_write_ctxt *wc, u32 cpos, loff_t user_pos, unsigned user_len) { - int ret, i, new; + int ret, i; u64 v_blkno, p_blkno; struct inode *inode = mapping->host; struct ocfs2_extent_tree et; - new = phys == 0 ? 1 : 0; if (new) { u32 tmp_pos; @@ -1610,9 +1610,9 @@ static int ocfs2_write_cluster(struct address_space *mapping, */ tmp_pos = cpos; ret = ocfs2_add_inode_data(OCFS2_SB(inode->i_sb), inode, - &tmp_pos, 1, 0, wc->w_di_bh, - wc->w_handle, data_ac, - meta_ac, NULL); + &tmp_pos, 1, !clear_unwritten, + wc->w_di_bh, wc->w_handle, + data_ac, meta_ac, NULL); /* * This shouldn't happen because we must have already * calculated the correct meta data allocation required. The @@ -1629,7 +1629,7 @@ static int ocfs2_write_cluster(struct address_space *mapping, mlog_errno(ret); goto out; } - } else if (unwritten) { + } else if (clear_unwritten) { ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), wc->w_di_bh); ret = ocfs2_mark_extent_written(inode, &et, @@ -1712,7 +1712,8 @@ static int ocfs2_write_cluster_by_desc(struct address_space *mapping, local_len = osb->s_clustersize - cluster_off; ret = ocfs2_write_cluster(mapping, desc->c_phys, - desc->c_unwritten, + desc->c_new, + desc->c_clear_unwritten, desc->c_needs_zero, data_ac, meta_ac, wc, desc->c_cpos, pos, local_len); @@ -1857,11 +1858,12 @@ static int ocfs2_populate_write_desc(struct inode *inode, if (phys == 0) { desc->c_new = 1; desc->c_needs_zero = 1; + desc->c_clear_unwritten = 1; *clusters_to_alloc = *clusters_to_alloc + 1; } if (ext_flags & OCFS2_EXT_UNWRITTEN) { - desc->c_unwritten = 1; + desc->c_clear_unwritten = 1; desc->c_needs_zero = 1; } -- 2.20.1