[PATCH v1 2/5] ntfs: preserve timestamps when creating hard links

[Baolin Liu <liubaolin12138@163.com>]

From: Xuewen Wang <wangxuewen@kylinos.cn>

ntfs_link() resets atime, mtime and ctime on both the source file and
the destination directory after creating a hard link. This overwrites
the source file's atime and mtime and the directory's atime.

Update only the source ctime and the destination directory mtime/ctime.
Mark both inodes dirty so these changes are queued for writeback instead
of relying on the earlier FILE_NAME write.

Signed-off-by: Xuewen Wang <wangxuewen@kylinos.cn>
---
Tested with the complete five-patch series in QEMU. Explicitly assigned
atime and mtime are preserved across ordinary hard-link creation and
O_TMPFILE publication. A separate persistence check set and synced
atime/mtime on the published file, then verified those values after
cache eviction, remount and a fresh boot.

 fs/ntfs/namei.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/ntfs/namei.c b/fs/ntfs/namei.c
index 0c84a5c..4442e1d 100644
--- a/fs/ntfs/namei.c
+++ b/fs/ntfs/namei.c
@@ -1663,12 +1663,13 @@ static int ntfs_link(struct dentry *old_dentry, struct inode *dir,
 	}
 
 	inode_inc_iversion(dir);
-	simple_inode_init_ts(dir);
+	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
+	mark_inode_dirty(dir);
 
 	inode_inc_iversion(vi);
-	simple_inode_init_ts(vi);
+	inode_set_ctime_current(vi);
+	mark_inode_dirty(vi);
 
-	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
 	d_instantiate(dentry, vi);
 	mutex_unlock(&dir_ni->mrec_lock);
 	mutex_unlock(&ni->mrec_lock);