akpm at linux-foundation.org
2016-Mar-23 20:11 UTC
[Ocfs2-devel] [patch 03/25] ocfs2: test target page before change it
From: Ryan Ding <ryan.ding at oracle.com>
Subject: ocfs2: test target page before change it
To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock.
Direct io data will not appear in buffer. The w_target_page member will
not be filled by direct io. So avoid to use it when it's NULL. Unlinke
buffer io and mmap, direct io will call write_begin with more than 1 page
a time. So the target_index is not sufficient to describe the actual
data. change it to a range start at target_index, end in end_index.
Signed-off-by: Ryan Ding <ryan.ding at oracle.com>
Reviewed-by: Junxiao Bi <junxiao.bi at oracle.com>
Cc: Joseph Qi <joseph.qi at huawei.com>
Cc: Mark Fasheh <mfasheh at suse.de>
Cc: Joel Becker <jlbec at evilplan.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---
fs/ocfs2/aops.c | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)
diff -puN fs/ocfs2/aops.c~ocfs2-test-target-page-before-change-it
fs/ocfs2/aops.c
--- a/fs/ocfs2/aops.c~ocfs2-test-target-page-before-change-it
+++ a/fs/ocfs2/aops.c
@@ -1406,12 +1406,13 @@ static void ocfs2_write_failure(struct i
to = user_pos + user_len;
struct page *tmppage;
- ocfs2_zero_new_buffers(wc->w_target_page, from, to);
+ if (wc->w_target_page)
+ ocfs2_zero_new_buffers(wc->w_target_page, from, to);
for(i = 0; i < wc->w_num_pages; i++) {
tmppage = wc->w_pages[i];
- if (page_has_buffers(tmppage)) {
+ if (tmppage && page_has_buffers(tmppage)) {
if (ocfs2_should_order_data(inode))
ocfs2_jbd2_file_inode(wc->w_handle, inode);
@@ -1541,11 +1542,13 @@ static int ocfs2_grab_pages_for_write(st
wc->w_num_pages = 1;
start = target_index;
}
+ end_index = (user_pos + user_len - 1) >> PAGE_CACHE_SHIFT;
for(i = 0; i < wc->w_num_pages; i++) {
index = start + i;
- if (index == target_index && mmap_page) {
+ if (index >= target_index && index <= end_index &&
+ wc->w_type == OCFS2_WRITE_MMAP) {
/*
* ocfs2_pagemkwrite() is a little different
* and wants us to directly use the page
@@ -1564,6 +1567,11 @@ static int ocfs2_grab_pages_for_write(st
page_cache_get(mmap_page);
wc->w_pages[i] = mmap_page;
wc->w_target_locked = true;
+ } else if (index >= target_index && index <= end_index
&&
+ wc->w_type == OCFS2_WRITE_DIRECT) {
+ /* Direct write has no mapping page. */
+ wc->w_pages[i] = NULL;
+ continue;
} else {
wc->w_pages[i] = find_or_create_page(mapping, index,
GFP_NOFS);
@@ -1665,6 +1673,12 @@ static int ocfs2_write_cluster(struct ad
for(i = 0; i < wc->w_num_pages; i++) {
int tmpret;
+ /* This is the direct io target page. */
+ if (wc->w_pages[i] == NULL) {
+ p_blkno++;
+ continue;
+ }
+
tmpret = ocfs2_prepare_page_for_write(inode, &p_blkno, wc,
wc->w_pages[i], cpos,
user_pos, user_len,
@@ -2266,7 +2280,8 @@ try_again:
ocfs2_free_alloc_context(meta_ac);
success:
- *pagep = wc->w_target_page;
+ if (pagep)
+ *pagep = wc->w_target_page;
*fsdata = wc;
return 0;
out_quota:
@@ -2400,18 +2415,23 @@ int ocfs2_write_end_nolock(struct addres
goto out_write_size;
}
- if (unlikely(copied < len)) {
+ if (unlikely(copied < len) && wc->w_target_page) {
if (!PageUptodate(wc->w_target_page))
copied = 0;
ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
start+len);
}
- flush_dcache_page(wc->w_target_page);
+ if (wc->w_target_page)
+ flush_dcache_page(wc->w_target_page);
for(i = 0; i < wc->w_num_pages; i++) {
tmppage = wc->w_pages[i];
+ /* This is the direct io target page. */
+ if (tmppage == NULL)
+ continue;
+
if (tmppage == wc->w_target_page) {
from = wc->w_target_from;
to = wc->w_target_to;
_