inconsistent timestamp update in rename() of xfs/fat/gfs2/ramfs/jffs2...

[Taesoo Kim <taesoo@xxxxxxxxxx>]

Hi all,

We've cross-checking patches from ext3/ext4, and found out
inconsistent implementations of other fs. We want to ask whether this
is intended or unexpected behavior. We will be able to send patches as
soon as confirmed/acknowledged.

Ref.

(ext4) 53b7e9f6807c1274eee19201396b4c2b5f721553
(ext3) 0b23076988b44b2c165e060248345de6f2337387

 | ext3/4: fix update of mtime and ctime on rename

---------------------------------------------------------------------
We summarized our finding:
  (* means what we believe is correct beahvoir)

<Linux 4.0-rc2>
                                        ramfs   affs    fsplus
                        vfs xfs fat gfs2    jffs2   hfsh
operation          | * |   |   |   |   |   |   |   |   |
===========================================================
new_inode->i_ctime | V | - | - | V | V | - | - | V | - | -
old_inode->i_ctime | V | V | V | - | V | V | - | - | - | -
old_dir->i_ctime   | V | V | V | V | V | V | V | - | V | V
old_dir->i_mtime   | V | V | V | V | V | V | V | - | V | V
new_dir->i_ctime   | V | V | V | V | - | V | V | - | V | V
new_dir->i_mtime   | V | V | V | V | - | V | V | - | V | V
new_dir->i_atime   | - | - | - | V | - | - | - | - | - | -

* Correct behavior in

   ext2, ext3, ext4, btrfs, f2fs, nilfs, reiserfs, cifs, exofs, jfs,
   ubifs, ocfs and minix
---------------------------------------------------------------------

Thanks,
Taesoo