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Subject[PATCH 2/2] Revert "f2fs: move i_size_write in f2fs_write_end"
Date
From: Chao Yu <yuchao0@huawei.com>

This reverts commit a2ee0a300344a6da76186129b078113354fe13d2.

When testing with generic/032 of xfstest suit, failure message will be
reported as below:

generic/032 8s ... [failed, exit status 1] - output mismatch (see results/generic/032.out.bad)
--- tests/generic/032.out 2015-01-11 16:52:27.643681072 +0800
+++ results/generic/032.out.bad 2016-08-06 13:44:43.861330500 +0800
@@ -1,5 +1,5 @@
QA output created by 032
-100 iterations
-0000000 cdcd cdcd cdcd cdcd cdcd cdcd cdcd cdcd
-*
-0100000
+1: [768..775]: unwritten
+Unwritten extents found!
...
(Run 'diff -u tests/generic/032.out results/generic/032.out.bad' to see the entire diff)
Ran: generic/032
Failures: generic/032
Failed 1 of 1 tests

In write_end(), we should update i_size of inode before unlock page,
otherwise, we will lose newly updated data in following race condition.

Thread A Thread B
- write_end
- unlock page
- writepages
- lock_page
- writepage
if page is out-of-range of file size,
we will skip writting the page.
- update i_size

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
fs/f2fs/data.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index e262427..5bb0bd2 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1700,11 +1700,11 @@ static int f2fs_write_end(struct file *file,
trace_f2fs_write_end(inode, pos, len, copied);

set_page_dirty(page);
- f2fs_put_page(page, 1);

if (pos + copied > i_size_read(inode))
f2fs_i_size_write(inode, pos + copied);

+ f2fs_put_page(page, 1);
f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
return copied;
}
--
2.7.2
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