On Wed, Nov 21, 2012 at 05:47:55PM -0800, Darrick J. Wong wrote: > On Thu, Nov 22, 2012 at 08:47:13AM +1100, NeilBrown wrote: > > On Wed, 21 Nov 2012 22:33:33 +0100 Jan Kara <[email protected]> wrote: > > > > > On Wed 21-11-12 13:13:19, Darrick J. Wong wrote: > > > > On Wed, Nov 21, 2012 at 03:15:43AM +0100, Jan Kara wrote: > > > > > On Tue 20-11-12 18:00:56, Darrick J. Wong wrote: > > > > > > ext3 doesn't properly isolate pages from changes during writeback. > > > > > > Since the > > > > > > recommended fix is to use ext4, for now we'll just print a warning > > > > > > if the user > > > > > > tries to mount in write mode. > > > > > > > > > > > > Signed-off-by: Darrick J. Wong <[email protected]> > > > > > > --- > > > > > > fs/ext3/super.c | 8 ++++++++ > > > > > > 1 file changed, 8 insertions(+) > > > > > > > > > > > > > > > > > > diff --git a/fs/ext3/super.c b/fs/ext3/super.c > > > > > > index 5366393..5b3725d 100644 > > > > > > --- a/fs/ext3/super.c > > > > > > +++ b/fs/ext3/super.c > > > > > > @@ -1325,6 +1325,14 @@ static int ext3_setup_super(struct > > > > > > super_block *sb, struct ext3_super_block *es, > > > > > > "forcing read-only mode"); > > > > > > res = MS_RDONLY; > > > > > > } > > > > > > + if (!read_only && > > > > > > + queue_requires_stable_pages(bdev_get_queue(sb->s_bdev))) { > > > > > > + ext3_msg(sb, KERN_ERR, > > > > > > + "error: ext3 cannot safely write data to a disk > > > > > > " > > > > > > + "requiring stable pages writes; forcing > > > > > > read-only " > > > > > > + "mode. Upgrading to ext4 is recommended."); > > > > > > + res = MS_RDONLY; > > > > > > + } > > > > > > if (read_only) > > > > > > return res; > > > > > > if (!(sbi->s_mount_state & EXT3_VALID_FS)) > > > > > Why this? ext3 should be fixed by your change to > > > > > filemap_page_mkwrite()... Or does testing show otherwise? > > > > > > > > Yes, it's still broken even with this new set of changes. Now that I > > > > think > > > > about it a little more, I recall that writeback mode was actually fine, > > > > so this > > > > is a little harsh. > > > > > > > > Hm... looking at the ordered code a little more, it looks like > > > > ext3_ordered_write_end is calling journal_dirty_data_fn, which (I > > > > guess?) tries > > > > to write mapped buffers back through the journal? Taking it out seems > > > > to fix > > > > ordered mode, though I have a suspicion that it might very well break > > > > ordered > > > > mode too. > > > Oh, right. kjournald writing buffers directly (without setting > > > PageWriteback) will break things. So please, change warning to: > > Maybe we should just fix this anyway? > > I still have the patch that adds PG_stable (and changes the
Page flags are in short supply. If you need a page flag to fix a bug in a single filesytem, there's a couple of reserved private page flags that can be used. i.e PG_owner_priv_1. I don't think using a glbal page flag for just this purpose will fly, though... Cheers, Dave. -- Dave Chinner [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
