Re: [PATCH v1 0/9] do not use s_dirt in ext4

On Tue 27-03-12 16:29:58, Artem Bityutskiy wrote:

On Thu, 2012-03-22 at 11:33 +0100, Jan Kara wrote:

quoted

  Then we have ext4_mark_super_dirty() call from 4 places - I forgot about
these originally... I kind of miss their purpose. Originally they were used
so that we write total number of free blocks and inodes in the superblock
but when we do not maintain them in the journal mode I don't see a reason
to periodically sync them in no-journal mode. Ted, what is the purpose of
these calls?

I do not understand what's the fundamental difference between journal
and non-journal mode. Why when we do have the journal we do not mark the
super-block as dirty in many places (e.g., in 'ext4_file_open()' - if we
do have the journal, when do we make sure we save the mount point path
change?).

  We write it at least during ext4_put_super().

May be it has something to do with behaving like the ext2 driver when
mounting ext2-formatted media with the the ext4 driver?

  I'm not really sure about this...

Jan, since Ted did not answer, may be you can figure out the reasons
from this commit message, which actually introduced the
'ext4_mark_super_dirty()' function?

  Anyway, attached are two patches which you can include in your series
and which should make your cleanups simpler.

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR