From b46637d59f1160dee5d8e03498e667ab36c2be04 Mon Sep 17 00:00:00 2001
From: Ryan Ding <ryan.ding@oracle.com>
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 <ryan.ding@oracle.com>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
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 69d7392f56d83..516ea896f13c0 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 @@ static int ocfs2_grab_pages_for_write(struct address_space *mapping,
* 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;
}
--
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